My new HISSandaROAR library is officially released now and as it consists solely of contact mic recordings I thought I’d share some of the most important aspects of recording with a contact mic that I’ve discovered the hard way – through experience….
The first rule of using a CONTACT MIC is not actually about the mic itself, its this:
1. WHAT IS IT PLUGGED INTO?
At a guess I’d say I own over a dozen piezo/contact mics of various forms, bought over the last dozen years, but only three of them deliver seriously useable results. And just one of those three ‘good’ contact mics cost ten times more than all the others combined, simply because the people who created them understood rule number one. Its not ‘just’ a contact mic, because the mic is only as good as what it is plugged into, and the only way to insure you get great results is to also match the preamp, and the only way to do that is to sell both as a package. I’m sure the reasoning behind this is very basic for anyone who has studied electronics but THIS ARTICLE spells it out…
“The problem with piezo guitar pickups and contact mics is that they are not well matched to typical audio inputs. By their nature they can generate a lot of signal, but they cannot drive a 50 kilohm typical line input. The pickup needs to work into a much higher impedance, typically 1 megohm or so.
The reason why these devices often sound tinny is because the piezo sensor presents its signal through a series capacitance which is small, typically 15nF or less. When wired to a normal 50 kilohm line input this forms a 200Hz high-pass filter, which eliminates the bass.
If wired to a consumer plug-in-power microphone input of about 7 kilohms impedance, the result is a 1kHz high-pass filter. Hence the reputation for poor bass performance…..”
YES, Its all about IMPEDANCE
I have seen people suddenly ‘discover’ contact mics. And by ‘discover’ I suspect it tends to mean ‘discover the work of someone else who has used one’ who then heads off to an electronics shop, discover piezo mics cost less than $5, buys one, plugs it in, gets a signal but then wonders why they don’t get the same results…. Well now you know, its all about the IMPEDANCE!!! Re-read that quote from the article above:
“When wired to a normal 50 kilohm line input this forms a 200Hz high-pass filter…”
How many times have I seen a piezo element wired up to a 1/4″ jack plug? Many, many times… And now that you know the above tech to be true, what will the results be? Unintentional high pass filter (aka small speaker syndrome) Take anything you’ve ever recorded or listened to, put a HPF on it set to 200HZ and have a second listen…. It suddenly sounds like its coming from a transistor radio from 1973. Great if that is your intention, but otherwise…..
The second rule of using a contact mic is more practical, it’s about attaching it. The results are often surprising – sometimes I’ve found a prop (this happened last weekend) and thought: “THIS will sound AMAZING with a contact mic” and then hooked it up & been thoroughly underwhelmed. What seems resonant & complex through the air may well be singular & far less interesting with a contact mic. But its when the reverse is true that things get exciting.
My old studio at Ropa Lane in Maupuia was originally owned by a metal company (literally, not the music genre) and when I took the lease they left some huge long I-beams in one of my warehouse spaces. When you lightly tap these 5m long beams they rang like bells, I loved them & couldn’t wait to get my contact mics out. But when I did they were WAY less interesting than through the air. I’m sure I’ll work out the pattern at some stage, but in many ways the mystery is actually a pleasant side effect. Not knowing the outcome means when you do stumble across a beautifully resonant body, time slows down… Recording this library for HISSandaROAR I’ve had many moments where through experimenting I’ve stumbled across a sound, and hours have past before I really became conscious again – I had a sore back for three days because of it. The situation generates what calls someone with a complex name I can’t remember calls ‘flow’ and the only other device that does that for me these days is my modular synth, but thats a different kettle of fish – I now know every time I switch it on, three to five hours will pass!
So if there is a rule 2 to CONTACT MIC club it is this:
2. YOU KNOW NOTHING
Keep an open mind & explore. A contact mic makes you look at the world in a different way, and for that alone you should be thankful. The flip side to those I-Beams I mentioned, was another prop I bought for practically nothing and hadn’t found a use for, at all – it was a slightly scodey stainless steel shower tray. The trick with it was suspending it so it was free to resonate, and one listen with a contact mic attached would make you wonder WHAT was creating the beautiful musical tones! It sure wasn’t what the literal description makes you think of, thats for sure!
No doubt I’ll think of more rules at some stage & continue this post, but also when creating the CONTACT MIC library I slowly developed a method for both creating and naming the sounds I was recording. Heres the analogy: when someone plays violin, you could happily define the sound created as consisting of four parts:
1. the human performer
2. the resonant body (the violin)
3. the activator (the bow)
4. the acoustic space
Any HISSandaROAR library you know is me, so I ignored part 1 but one aspect of using a contact mic that bears discussion is rule 3:
3. THERE IS NO ACOUSTIC
Check this video to see what I mean:
Until the drill bit meets the metal surface that the contact mics are attached to, there is no sound. You could hold a contact mic up & scream at it & record nothing! As with the drill that can work to your advantage. You don’t have to worry about extraneous noise – you could be listening to loud music and recording with a contact mic with zero leakage! But it is also a key factor in the use of the sounds – because there is no acoustic to help cue the listener what produced the sound, they appear almost more abstract. But due to their great resonance they work brilliantly as hidden components of complex composite sounds!
Also referring back to that list above, I became fascinated with parts 2 and 3. So maybe rule 4 is this:
4. SEPERATELY CONSIDER THE RESONANT BODY AND THE ACTIVATOR
With experience I collected up various activators (see photo below) and of course, only some activators would work with some resonant bodies… But it gave me a language & a mental model to use when attempting to identify likely candidates, and equally that is invaluable for the imagination.
Most of the resonant bodies and activators I used in the HISSandaROAR library are shown, briefly, in this video:
As far as low end goes, you can hear in that video some of whats possible. Heres some recordings of that big yellow half deflated balloon – the low frequencies created are beautifully expressive:
Rule number 5 isn’t really a rule but requires thought:
5. HOW DO YOU ATTACH A CONTACT MIC?
I use two methods, depending on the resonant body. First I always carry a roll of thin double sided sticky tape which works well if the surface is clean & flat. Its fiddly to apply and can be frustrating if the surface is dirty, because as soona s you move it you have to replace the tape, but when the surface is clean its my preferred method…. The other method I use sometimes is a product called BluTak – its intended for attaching posters to the wall, but it works well when the surface is more irregular or dirty…. It pays to always have both with you when recording, along with the always essential gaffer tape. In some extreme cases I’ve used Blutak between the contact mic and the surface and then wrapped the whole thing in gaffer tape. But you have to be careful as too much tape can deaden the very resonance you are trying to record…
Rule number 6 is
6. PLEASE DON’T EMAIL ME ASKING WHAT MODEL OF CONTACT MIC I USE
I’ll list the models below, just so I can forward this article any such emails in the future!
Most of the recordings in the new library were done with two Barcus Berry Planar Wave contact mics combined with & two of their 4000XL preamp. Here is a link to the Barcus Berry product page. I like the 4000 preamps they come with due to them being phantom powered and having a 12dB switchable pad. I could not have cleanly recorded some of the metal shrieks & creaks in the library without that pad!
The other contact mic I own is a Trance Audio Inducer, which appears has been discontinued (incorrect – see update below) but here is a link to the Trance Audio site. Their preamp runs on two 9volt batteries which I like less than phantom power but I prefer Trance Audios actual contact mic capsule. Here is a photo comparing the two:
There are many other types of contact mics out there, the first I ever heard of was the C-Ducer but the contact mic element seems a bit big & awkward for my applications… Feel free to comment with any others you have experience with?
Lastly rule number 7 is
7. LEARN THROUGH EXPERIENCE
A contact mic is like any microphone, you have to learn to use it… and (hopefully) you never stop learning! So in the meantime here’s a preview of the new library:
check out HISSandaROAR CONTACT MIC Library here!
UPDATED Nov 12: I got an email from Trance Audio: “We still custom make the mono Inducer System, and we also do a custom modification of our stereo Amulet System to make it more useful for SFX work. We don’t list these on our website as they are not stock items, but are happy to enquiries”
UPDATED 2022: Two more Contact Mic Libraries released since:
HISSandaROAR SD018 CONTACT MIC TWO
HISSandaROAR SD049 CONTACT MIC THREE
Tim Prebble = The Good Teacher
Really, I have learned so much reading your blog.
Couldn’t agree more!! This blog is really useful and of course this post also. I already bookmarked it and Thank you so much for the wonderful sharing.
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wow, i just discovered this site through synthtopia, fantastic sounds mate and very useful info re: the 200Hz barrier..
I use contact mics for certain things, but still learned from your article. And the sounds in your library, amazing. Congratulations for this release.
Great article and fantastic sounds, Tim! The balloon sounds are fascinating.
FYI – Trance Audio are actually still making their Inducer, but it is made to order / custom item only. It took about 8 weeks to ship when I purchased mine last spring.
Great article.
One thing I’ve found with piezos is that a drop of superglue gives a closer connection and better transmission than double sided tape.
Obviously this is only relevant if you want a piezo permanently attached to something, but the difference is marked.
I’ve used Glue Dots with a lot of success when attaching a piezo: https://www.amazon.com/Glue-Dots-Permanent-Dot-Dispenser/dp/B004OKTTWM/
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wouldn’t it be way better for all those sounds if you throw the foam away and let it vibrate freely?
sorry, what foam are you referring to?
do you mean underneath the prop? you should try it sometime so you know for yourself, but a metal object sitting on wood that is struck will rattle ie metal against wood, rather than freely resonate – try it sometime
I have used styrofoam to mount metal objects for music… it works wonderfully. The acoustic sound is notably improved… and it provides and excellent surface for a contact mic. You can have multiple objects just sitting on the styrofoam, and the mic pics them up well. The first time I saw this it seemed counterintuitive. I believe the key to the good sound to be due to the lightweight (low-density) nature of the foam structure and slight rigidity of the polymer. But idk.
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Great article, will be very useful, although it needs some time to digest it all!
I think that the complicated name you refer to (“The situation generates what calls someone with a complex name I can’t remember calls ‘flow’…”) is Mihalyi Czikszentmihalyi, and the book is Flow: The Psychology of Optimal Experience (1990).
yes, the book is sitting on my shelf 😉
Too fiddly to type; he’s got what you could call a ‘copy & paste’ name.
heh heh i bet even >he< has a TextExpander shortcut for typing his own name!
Great stuff! I use Silly Putty to stick contact mics to random stuff. Basically the same thing as Blue Tac.
Thanks, you inspired me to solder together a piezo rather than use the cheap clamp thing I’ve been recording with and it’s great:
http://bassling.blogspot.com/2011/11/how-to-make-contact-microphones.html
I looked into getting a Barcus Berry but can’t see any in the country and the shop I asked in the US reckon they don’t freight well.
There’s always some bit of kit one wishes one had, eh?
FWIWI I bought my two Brcue Berrys off Ebay, shipping ll the way to NZ no problem
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Late, as usual, but I’m delighted to have discovered this. A quick question, What do you use for a recorder? I have a Zoom H4n. Will this be compatible with the pick ups you listed above? And why do you use two of them. Thanks ESA
I use Sound Devices recorders – 722 and 744, as they have very clean preamps. I’ve never used a Zoom H4 but I understand they are not so good with very quiet sounds…. I use two contact mics because we have two ears
Thank you Tim! . . . For a cool and informative article ~ I am an electric guitar player.. and I play in stereo, through two amplifiers.. because we have two ears! It’s amazing how much flak I get from recording engineers and soundmen!
Marc, are you stereo mic’ing your guitar at the same time? Otherwise, it would be a very different scenario then what Tim’s taking about.
I love this article Tim. I’m gonna by few of those mics that you’ve mentioned. I’ve really liked the sound of piezo mics. I can see the difference hugely. Also wanted to say, that what if you’d combine contact mic with the X/Y couple for the acoustic feel if you want to get more of it. Since contact mic sounds dry like this, it would be amazing also for an attack of the sound effect, since it’s picks it up so different from usual mics. Cheers.
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1 minute autohypnosis Project
Send us a minute of sound in any system by mail or e-mail.
Visit our webpage
http://www.mutesound.org/?page_id=83
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http://www.youtube.com/watch?v=fXIeFJCqsPs
i think this is who you were referring to when you said “flow”….
and that lecture was PHENOMENAL!!
I am having a problem building this “drawdio” device for the purposes of making a pool of water ‘touch-sensitive’ and contact mics are, maybe, a feasible alternative. Which is how i discovered your site. i wanted to see if i could use a contact mic to trigger a video black out using MAX MSP.
thank you for reminding me of FLOW.
Hello,
I’d like to use contact mics with my (soon to be delivered) iPhone. Do you know which preamp/devices I should invest in?
Many thanks,
Ames
i don’t think there is anything particularly hi rez available as a preamp for an iPhone, but I wouldn’t really know sorry – do a search and/or ask at social sound design
http://socialsounddesign.com/
Thank you, I will do.
Great page on contact mics, thanks for all the info. I just found an interesting contact mic that uses piezo-polymer film (PVDF)and also has a built in preamp/buffer circuit. It’s the Measurement Specialties CM-01B contact mic: http://www.meas-spec.com/product/t_product.aspx?id=5431 and it’s only $32. It has a nice freq response and it’s touted as being extremely sensitive.
Nobody in the country has these in stock so I’m currently putting together a group buy with a few of my audio geek friends to curb their $25 handling and $35 shipping fees. I should have them within a few weeks from now and I’ll report back here what I think of them for hifi applications. Either way, I thought you might be interested in something that’s a little different from the norm.
thanks Derek! Please do let me know how you get on
Thanks Tim for for all the sounds and advice.
I have just recently bought a Cold Gold Buffered XLR Contact mic which should arrive in Sydney in the next week or so from Canada http://www.contactmicrophones.com
Do you have any experience with these? I have a Zoom H4n that I’m to be using it with, and got this particular model because it had it’s own preamp so I didn’t have to rely on the H4n pres. Any advice with this type of contact mic and getting a clean signal with my setup would be appreciated!!
Ben
Hi ben
I’ve never used them so please do let us know how you get on
hey tim,
nice article, i really enjoy reading it.
did the mics differ regarding its frequency respond?
did you compare them?
thanks, Johannes
not hugely….
When I get around to writing a review of the new Trance Audio contact mics I will do a recording using one side of each – the placement creates such huge variance it is otherwise difficult to compare….
with mics i meant the barcus berry and the trans audio…
didint see your reply, thanks.
does the use of xlr on the bb result in greater signal noise ratio?
minimally maybe….. I never compared that aspect – balanced XLR should always be better but it is very short cable run, so not like running 30m of mic cable in an EMF dense area…
hey there. I’ve been trying to get a watch’s ticking sound with a contact mic into arduino’s analog input. I can get heartbeat, but no luck with watch ticking. Any ideas?
What contact mic? What preamp? Do you have a sensitive contact mic and a clean preamp with correct impedance matching?
Hi Desmond. I’d like to know how good was the heartbeat you obtained. Were there any impedance issues?
Well I have no idea how to do find the required impedance matching or required preamp. Contact mic is sensitive enough I think, because when I connect it to a Marshall amplifier, I can hear the watch ticking quite well. Also is there a way to use Marshall amplifier’s speaker output as my analog input?
Compact mic is a piezo mic btw. Forgot to mention.
if you read the article above you would appreciate the necessity for a preamp & for impedance matching…. I think you need to do some learning/study about levels & impedance – i know nothing about arduino ie what level does it expect at its analogue input?
As the link about impedance matching above states, the output from a contact mic is very small. Thats why you need a preamp.
What Marshall amplifier are you talking about? A guitar amp with a speaker output? That is made to drive a speaker impedance….
Read this article for a start:
http://www.soundonsound.com/sos/jan03/articles/impedanceworkshop.asp
and the one linked above ie
http://suite101.com/article/get-better-sound-from-piezo-mics-and-pickups-a72764
Arduino accepts 0-5v from its analog input.
Yes it’s a small (pocket) guitar amplifier. Sorry about my little knowledge on impedance,levels. But I needed a quick way to solve this problem, although now I see it can not be that quick.
build this simple circuit
http://blog.makezine.com/2011/12/20/collins-lab-diy-contact-mic/
mic–>that circuit–>analog input?
yes!
the two outputs form the piezo go to INPUT SIGNAL & GROUND
then the OUPUT of that circuit goes to the Arduino input
its only 4 resistors, a transistor, two capacitors & a 9v battery
I got the sound by salvaging Marshall amplifier’s amplifying circuit and matching its impedance to our Arduino’s analog input by adding high resistances. That was a good improvement on my understanding of impedance over a night. I’m reporting this so it’s helpful for others too. And Tim, thank you for all your help and quick replies.
Desmond
Tim , or who ever els ….
Would you be open to trying this with the DAzzo pickup ?
It has three walls that hear incoming sound waves in 360 .
Thanks
Teddy
thanks Teddy – just received a pair of contact mics from you, will start playing with them the weekend
Very interesting and useful. I recently discovered that by connecting
a jfet very near to the piezo disc it acts as an impedance converter
similar to the efect in an electret mic.This eliminates all the problems
associated with low output impedance and preserves the low freqs.
Have been struggling for years with the issue of how to get your beautiful sounding acoustic instrument to sound less than disappointing through an amplifier, and how to control feedback. I have just got to the stage of running tests, that is, listening to the same sound (the one my ears hear) through different kinds of mics. Attaching piezos to things, hitting and scraping things, singing into mics, piezos. Thought I was losing the plot, then I found your site. Cheers
HI Andy,
I’m a guitarrist,… do you know how to apply all these info to get better sound from my guitar piezo.??
I appreciate your help…cheers
Adrianny
Do you mean acoustic guitar? if yes, then talk to Trance Audio
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Can you suggest a good contact mic for picking up very very quite “sounds”?
I am building an automatic safe cracker for a school project and I need something that can “hear” the “tick” when the correct number is dialed in.
i have included links to the contact mics that I use in the article, the only better one that I know of for very, very quiet sounds is the discontinued Sanken contact mic which used to sell for approx US$3,000
The nikkei acoustics Contact Mic is ideal for this.
Comes with amplifier which has audio filter control.
No mention of frequency response on any of the websites?
how would / does the best of the two worlds work together (the phantom powered barcus berry 4000 preamp with the better transaudio transducers) ?
does the barcus berry pre work well with other piezo bender style mics too?
does it provide gain or is it just a direct box? i only see a knob for monitor out…
interested in the barcus berry pre, but not as interested in the barcus berry transducers (for the mounting difficulties you have already mentioned).
I’ll do some tests when I get time
that would be appreciated, looking forward to it.
Hey there Tim,
I just wondered what that putty stuff is you use to attach the barcus berrys? Is it just blue tack? does it affect the sound much?
Did you read rule #5?
It depends on the object how much it affects the sound… some objects it has no effect, on others it is unusable
Oh dear. I’m very sorry. Thank you for your reply and your patience.
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Hey, awesome article. I have a Mackie Onyx 1620 board which has 1Mohm input impedance (the guitar buttons) on channels 1 & 2. Do I still need a buffer circuit or can I plug right into the board?
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Stumbled across a man on kijiji selling a pair and found this page. Can anyone describe results from an acoustic guitar?
Thank you
Hello 🙂 I don’t know english very well, i read what you write up, but i still want to ask you, if i make a contact mic, and i plug it in to a 2.1 speaker it will have good sound?? or if i connect it to a pc..
Please answer, i have to make a project 🙂
Thanks in advance 🙂
it depends – what contact mic? what preamp? what prop?
Tim,
I’ve contacted Trance Audio and indeed they do still make them. There is quite a price difference. I’m trying to determine which of the two to buy. You say you prefer the Trance Audio mic capsule more than the Barcus Berry. Why is that? Any other arguments towards one or the other if you could only do one?
Thx
Joe
I use my Barcus Berry mics more than the Trance Audio ones
The Barcus Berry preamp is better, the mic is very good but it is breakable – i have broken 3 of them and have had to replace them…
The Trance Audio preamp is good but I hate using 9 volt batteries when I have phantom power available – this is a design issue they have no interest in fixing. The mic element is more robust…
If I was buying only one it would probably be the Barcus Berry
Tim,
Thanks for the quick reply. A two part question now.
What about the Trance Audio mic with the Barcus Berry pre? Could you mix them? If you could would you prefer the Trance Audio mic? Better specs?
Also I have a nice pre that I like. I’m assuming I could use it with the Barcus Berry mic or Trance Audio mic too if the above is possible. My pre is a portable single 9 volt pre from the Sound Professionals that uses 9volt DC bias power.
Thanks again for your time. I love your sound library. I do occasional film and commercial work. How does the licensing work with your sounds.
Joe
Using TA mic element into BB preamp doesnt work well at all, unfortunately. And same vice versa.. I can only presume these preamps are very tightly matched to the mic element.
Both the BB and TA preamps output balanced audio via XLR
re licensing
When an individual or facility buys my libraries they are buying a license to use them, with specific parameters & restrictions (eg cant be resold etc etc) – of course an individual license is quite different to a site license.
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Good for you! The question will be whether the work contact microphone -> Di Box active with linegraund -> manantz pmd 661? I did the test, but only through the audio Mbox 2 mini, sound like, but had a terrible problem with background noise. I understand this because of the ground, or the option can not be used? Thanks)
wouldnt have a clue, sorry – I’ve never used a DI box with a contact mic, & never used a Marantz PMD661
thank you anyway!!then I’ll try and let you know the result))
Great article. I love the heading: You dont know anything. This could apply to all of life eh?
Hello! I read through your article and am fascinated by this topic. In short, I am songwriter turned musician and recently built a wash tub bass as a joke because my friend Tom had one years ago in Texas. And then, something happened. I started trying to improve the volume via mics so I could have a chance to hear what I was doing when our band was performing. Now I am obsessed. My current interest is in finding the right strings that will provide a good pitch as well volume. I have been using para chord and yesterday tried aircraft cable from 1/16″ to 1/8″ because a test revealed the steel wire (wound) provided an exciting new level of actual standout sound! However, when all was said and done, since I have four strings on my forked stick strung to the wash tub, it was almost impossible to tension each one the same given their various diameters. Also, they did not provide much in the way of pitch or tone i.e. different musical notes, so really, steel cable is not the solution. I am using an acoustic guitar pickup (Dean Markley acoustic transducer) since it works better than the dynamic mics including a kick drum mic. So, any ideas. I realize I have two separate problems, string and audio which in your expertise includes the amp or pre amp that drives the pickup. I am wondering if I can wind some thin wire around my para chord which at least provides different notes and I can tension the four strings the same and thus have the transducer pick up more volume? Thank you for your comments in advance! Sincerely, Brad Smith
With either the Trance Audio or Barcus Berry system you could generate bass that would make a sound system shake the foundations of a building!
One consideration is powering – the TA uses 2x9V batteries whereas the BB uses phantom power which may not be available to you when using a bass amp….
I think I prefer the BB, but YMMV
Fantastic article! The best I have seen on the subject. We manufacture The Cortado, a Balanced Output Piezo contact mic, and soon, a phantom power module to accompany it. We saw the need for an affordable contact mic with a strong, clean, quiet balanced output that is impedance-matched to the recording device, eliminating the preamp.
Again, great article! Great sounds.
Thanks – please let me know when its available?
the Cortado is available now, as a kit or ready to use, but it has been selling better than expected and we expect to stock out around October 20. It should be back in stock by the end of October. The Espresso portable phantom power supply should be released by the end of the year, maybe by Christmas. Both come as kits or ready to use, both are cheap.
I’ve bought a couple of your Cortado mics with the Espresso phantom power kits and they are fantastic. Would totally recommend.
Your article has enlightened me quite a bit. I’ve been trying to come up with ways to listen to my watch tick as my hobby is watch making and repair. I can buy the equipment to perform what I need to do but thats not as much fun.
I have come up with some ways to actually hear the tick that I otherwise could hear only by positioning the watch to my ear. Now all of this has me thinking thanks to your enlightenment.
Thanks
glad to hear its not safe breaking 😉
Could Behringer ULTRA-DI DI100 be the solution for the unwanted high-pass filter with line or mic input?
I don’t know – is its impedance matched to a piezo element?
It seems so but I don’t understand very well. I will give it a try!
I have a uni project for in a couple of weeks, I have decided to make tubular bells which have Piezo transducers inside the tubes. My lecturer has recommended i use resisters between the transducer and the output lead. Have anyone got any links or recommendations of a idea resister to use?
Huge thanks!
If anyone can help please email: Benjamin.vennell@dbsstudent.net
you need to match impedance – did you look at that simple circuit I linked to?
How would you characterize performance specifications for contact mics? For all other mics, we have a standard medium through which the audio information is transmitted to the mic (the atmosphere). With contact mics, there is no transmission medium. The performance of the mic is dependent upon the object to which it is stuck. I see little information on the subject online. One fellow suggested sticking the mic directly to a hifi driver and feeding a sine sweep signal to the speaker as a reference, and analyzing the signal picked up by the mic. What do you think?
“With contact mics, there is no transmission medium” – thats not correct, there is a transmission medium: its metal, wood, polystyrene, glass, rubber, plastic, perspex or whatever the contact mic is receiving the source of the vibration through.
Wow, thanks so much for this guide! I’m piecing together all the bits I need to record some original impacts, scrapes, booms, etc. and this is invaluable!
So I was comparing the impedance of the BB pre-amp to what’s typically found in most audio interfaces with a hi-z setting and it seems like this might be sufficient? The Steinberg UR-44 has two hi-z inputs that run at 1 mega ohm, so do you think they’d work for the “stereo” contact recording , and use the two remaining mic inputs for a dynamic and condenser for a close mic sound? Is there any risk of me damaging the pre-amps in my soundcard with contact mics?
And just one other question – I’m seeing a lot of mics online marketed as being for mandolins, violins, etc. Are these essentially the same as what you’re using?
Many thanks again!
Contact mics made for specific instruments are made for specific instruments – so think about the frequency range of a mandolin or violin and then think about the frequency range of a double bass, or piano. They are not the same right?
& sorry but I have no idea about any Steinberg preamps – I’ve never used them & don’t know anything about them. The contact mics I use are matched to the preamps, and I imagine its more than just impedance. If I was making them I would analyse the impedance & frequency response of the contact mic element and then build a preamp accordingly.
Thank you for the swift reply Tim! Oh yeah I get that – I just wondered if maybe they were labelling them as such as that’s the most common use, but if they’re actually purpose built for those instruments I’ll give them a miss and look for something with a wider response.
Yeah I mean the Steinberg stuff, obviously, is suited for conventional music making. I guess my worry was that I could push its pre-amps past their limit and end up trashing a perfectly good interface! I’ll do a little more research then. I’m checking out some of the links to mics and hardware that your other readers have left so maybe I’ll find something there. Cheers anyway!
cant imagine you could do any damage (but dont quote me on that 😉
Hi,
Great post… and impressive blog in it’s entirety… thanks!
I’m an audio student, looking at using some contact mics and hydrophones as part of a major project for my degree. Obviously studying full-time has it’s financial constraints, so I am planning on making use of my existing DR-60mkII recorder and try to balance the quality vs expense on the mics.
I’m interested to see if Tim, or anyone else has had any experience with the C and D series products from http://hydrophones.blogspot.com
Any other economical suggestions welcome.
Cheers!
Thanks for replying Tim. I have had good results with the typical disk piezos using a Tech 21 Para Driver DI (SansAmp). Certainly not as matched as one of your preferred options, but a good place to start given the relatively now cost.
This thread seems somewhat active so hopefully I can contribute AND have a question answered!
I’m interested in using contact mic technology on percussion and have recently been reading up on Zildjian’s Gen16 line of hybrid cymbals. It uses a sensor that Zildjian only refers to as a “vibrational transducer” that is connected to their proprietary preamp. I think Zildjian is being somewhat coy with their description as not to fully broadcast the inner workings of their product. But, I’d like to potentially use only the sensor for some unconventional applications and knowing the general technology the sensor is built on would help.
Any speculation on what the sensor technology generally is? I would assume it’s essentially piezo, but I don’t know enough about the engineering of transducers to know whether there are other types of transducer technologies other than piezo.
Here’s some links to the product!
https://zildjian.com/gear/direct-source-sensor-kit
https://zildjian.com/gear/direct-source-pickup-sensor-thumb-screw
https://zildjian.com/gear/direct-source-pickup
Any speculation would be nothing more than that, but whatever the technology I imagine a lot of R&D has gone into matching the sensitivity/level & frequency response to the specific use. Sound travels very rapidly through metal, and even subtle playing on cymbals is relatively loud so I’d suspect its more of an issue avoiding clipping & distortion, than being sensitive enough. This may or may not limit its use for other recording purposes…
Thanks a lot for a great article.
I wish to enter the world of natural/material sound experiments and I wonder what are the benefits of using contact mics over cardioid condenser mics to record them.
Did you actually read the article? The advantage totally depends on WHAT you are recording and WHY. For some sounds a contact mic is of no use at all
I did read the article and haven’t found the answers I was looking for. I’ll try to do a comparison on different materials/settings with both my Gefell cardio. and the Barcus Berry I’ll hopefully be receiving in a month or so.
so the section on “THERE IS NO ACOUSTIC” had no meaning to you?
Why are we debating on the quality of your post ? I already said I thought it was great. I guess I was just looking for additional experience sharing on the matter, that’s all.
You asked “what are the benefits of using contact mics over cardioid condenser mics” – THERE IS NO ACOUSTIC is an important part of that answer. Think about it
It is very interesting for me, if a contact microphone or accelerometer can be used as noise/noise pollution sensor mounted inside relatively small metal box mounted over the street. Metal box should act as a resonator, I guess.
Thank you very much for great article, Tim!
Would you be so kind to tell, do you use any kind of post-production? (i mean noise reduction maybe … or some eq correction) Or basically, you leave recorded material “as is”? Thank you.
That totally depends on what I am recording the sound for…. if for libraries then no processing, as it would presuppose the use… if for own projects then it depends on the project and how I will use the sound
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Tim,i
I am fascinated by your knowledge and experience. I am a musician that recently lost all of my hearing in my left ear. I will soon be at the point of decision to have a bone anchored hearing implant. Through research I have found that these devices are small and have a low limit of around 400hz up to around 8000khz. I have tried several of the bone conduction headsets on the market such as Aftershokz, They sound tinny and lack bass, just as you mentioned. There is much on the web for building your own bone conducting headphones using piezoelectric transducers from radio shack and other sources. So I have been thinking about what it would take to make a small piezo capable of a greater frequency range. Do you have any ideas on the subject?
Thats tough news, I dont have any experience with bone tranmission of sound although it is a fascinating subject…
It might be worth researching the deaf percussionist Evelyn Glennie as I would suspect you will still feel (and even more so possibly) low freq eg under 200Hz through resonance in your body… The hard part will be losing accuracy in hearing the fundamental freq when hearing and playing music, but a lot of great music was recorded and produced in mono, so hopefully tour other ear is ok?
There is a small vibrator speaker which you attach to a surface and it then uses it as its diaphram, cant remember brand name but I have one at home so could check next week. I bought it on eBay
sorry I cant be more help
I use an acoustic guitar simulator pedal in between my piezo classical guitar jack n my guitar amplifier, using the pedal as a pre-amp. Then I have got real good classical guitar tones.
congrats
Tim: Did you ever get a chance to try and review the Cortado that is mentioned above in communications?
Thanks, Alan
http://zeppelindesignlabs.com/product/cortado-balanced-piezo-contact-mic/
I didnt sorry – busy with other stuff at the time – will find it & be in touch
Hello once again Tim,
Some times ago i saw a video of contact mic performance (kind of electroacoustic improvisation) and guy touched mic by fingers and even took mic itself in hand and moved it on the table surface … i’ve tried do to the same and faced with problem of very spiky transients popping out. Have you ever tried this technique and if so how you deal with possibly spiky sounds (usually in high/high mid area)? I know that when i use (for example) cardioid condenser mic i can move mic a little bit away from the source and it helps to take smooth recordings without being spiky … but contact mic – it’ another story. Yes, i can move contact mic away from the source and sometimes it helps also (but a recorded sound a bit muffled in comparison with sound recorded much closer to contact mic) What when i want to use performance technique when i hold contact mic in my hand and possibly moving it across some surface? How to tame high freq transients? Do you have any experience with it?
Thank you.
Wouldn’t have a clue sorry… I would never hold a contact mic in my hand while recording – it needs good strong direct contact with the resonating body, I don’t see how holding it in your hand is going to help that?
Hello Tim and Happy New Year! 🙂
Today i’m trying to connect main output of my Barcus Berry 4000 XL preamp into Line In of Avid HD Omni interface – but no luck 🙁 I can’t hear any incoming signal … The only sound i hear is when i connect Barcus main output into mic or instrument input of HD Omni – but in this case i have two preamps connected one into another (Barcus preamp —-> HD Omni preamp) thus i have more noise. Strange, but why i can’t hear any incoming if connect in Line In – it’s ordinary thing to put preamp in line input. If it’s not a big secret, how do you connect your Barcus into interface (or portable recorder maybe)?
p.s.: as i understand, second output of Barcus (named Monitor out) is for headphones?
Thank you and Happy 2017!
BB preamp is powered by phantom power isn’t it? Phantom power only exists on microphone input… I plug XLR balanced out from BB preamp to XLR mic input (with phantom power enabled) on my Sound Devices recorder… would be same for Computer io
Hmm … but BB also has it’s own battery inside so it can operate without 48V phantom.
mine doesnt
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Piezo-mic voltage converted to note data, Synth and/or MIDI…
Hi, hopefully you can guide me in the right direction. I need a module that will use incoming piezo mic voltages (from tap dancing on a mic’d surface) to create various pitched notes. I don’t know whether a piezo-voltage to MIDI converter exists, or a synth module that can take the incoming piezo-voltages and use them to generate various pitched notes… do you have any suggestions, ideas of where I can look, what I might use?
Note: Here’s a solution that Nicholas Van Young designed (I asked him how he created the note data, but he wrote only ” I have a different module that has multiple outs that I can do more advanced patches, such as use velocity to pluck filters and so on. Here I’m using a Sample and Hold, attenuated, running to a quantizer. Then typical Filter/FX path. Make Noise O-Coast is my the main voice, and the drums are a pocket operator, clocked from O-coast” – https://www.facebook.com/nicholas.young.372/videos/10155115700334872/
Background: I’m a tap dancer want to use this module with my hardware and software looping setups…. I’ve been working with various sorts of hardware looping: EWI USB to PianoBox USB GM synth + live mic recording to Jamman XTs processed through Digitech Vocalist Live, Zoom G2.nu, Digitech Timebender, with contact mic drum triggers to Drum Modul, etc.. and software looping: Mobius VST in Abelton Live ontrolled by FCB1010 with EWI USB and live mic and MIDI drum pad…
Thanks much, Bob T
Its not ‘piezo voltage’ – it is sound. So you want something to analyse sound for its pitch content, and output MIDI. I sincerely doubt there is hardware existing that can do this but I wouldn’t have a clue as have never wanted to do it…. but it sounds like something Max could be programmed to achieve.
https://cycling74.com/
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The link in part 1 is broken. I couldn’t trace an article by Richard Mudhar with exaclty the same name, but I think that this is probably the one you were linking to: http://www.richardmudhar.com/blog/using-piezo-contact-mics-right/
Dear Team,
I’m Anna. I read seen your blog today and I think you have a lot of awesome articles. Moreover, your site content holds quite a similarity with my blog.
For that reason, I’m interested in connecting with your site through native ways, in the form of content. Do you accept sponsored posts?
To make things easy, please provide me with the estimated cost involved for taking the the following types of links on your site:
1. A link on your homepage
2. A guest post provided by me
3. A sponsored post written by you
4. Link placement on your existing articles
I look forward to hearing from you soon and wish you much success in your endeavors.
Kind regards
no, no, no & no – that all feels completely disingenuous
thank you
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Hi, Tim. Very grateful for your knowledge and expertise!
I’m writing a new piece for the the Australian harpist, Alice Giles, which will be performed outdoors with some live eolian harp sound mixed in. The eolian harps are at at some distance from the performance stage. Is there such a thing as a wireless contact mike? (the more wind, the better the eolian sound . . . and the more direct wind sound interference there is with a standard mic) Any suggestions much appreciated.
Thanks!
Tim G
Well… a contact mic is an audio signal, and there are plenty of options for transmission of audio wirelessly – you should talk to a production sound recordist or prod sound rental company and get advice, as they use wireless for recording actors all the time and will know what sort of range etc is possible… If you use eg a Barcus Berry Planar Wave you will also need phantom power for the preamp, which is near the contact mic so would need to factor that in too
and Happy New Year!
I’m thinking of securing a contact mic piezo/trigger to a drum head by sandwiching it between two strong neodymium magnets. Would magnets affect the voltage/signal at all or adversely? Would it require any special shielding maybe? Thanks for your input.
I dont know sorry, I have never tried & do not know enough physics/electrical engineering to know
I have been using contact microphone in sports for over 20 years.
Check out a small sporting event in South Korea. There are contacts from Audio Technica in the Ice at Figure Skating.
Hi Tim. Thank you for your insightful informations.
I want to ask if it is possible for piezo to pick up a person’s voice in a good quality. I tried doing it, but the voice sounds very dull (like a telephone from 30years ago) and is different from my actual voice. Is there another type of contact microphone/transducer that could do this?
Also, as much as I like how piezo could pick up little sounds details, it annoys when I touch piezo by accident and makes unnecessary sounds. Is there a material that I could put on part of piezo and would block the sound when I touch piezo/surroundings by accident? Your suggestions would be very appreciated.
Thank you,
Angela
Contact mic picks up vibrations – a good way to test a possible location is to lightly put your finger on it & if you can feel vibrations then put the mic there. Therefore for voice I guess you could try sticking it to your throat or voice box. I read a local singer used to put a contact mic between her teeth ie clench/bite it… But I would not expect to pick up ‘normal’ voice sound this way, as part of what gives a voice its character is the size of throat, chest, voice box etc… whereas contact mic picks up just the close resonance/vibrations… But experiment!
I have no idea for material to isolate sound from contact mic – anything is going to transfer the vibrations from you touching it, you just need to be careful with placement of contact mic and the cable, as the cable can also transfer unwanted noise to the mic.
Hi Tim,
Thank you for your reply. I did try putting it on my teeth and did capture my voice a little. I will experiment more. 😀
Hi Tim and thanks a lot for your article, I’ve learned a lot from it and from the subsequent comments!
I am going to make my first experiments and I was wondering if I can overcome the impedance problem for piezo mica by using this small mic preamp found on Amazon:
https://www.amazon.it/dp/B078LYBYZG/ref=cm_sw_r_cp_api_i_end9AbHTE8WRW
Maybe even get power from phantom?
Thanks in advance ^_^
Sorry I dont have enough technical knowledge to advise whether that preamp will solve the impedance issue or not….. After seeing it discussed online I bought a pair of these BigAmp Piezo, which are purposefully designed for use with Piezo contact mics, so might be a safer bet (I havent tested mine yet)
http://tritonaudio.com/bigamp-piëzo.html
Hi Tim,
Great article. I’ve read it several times!
You say they still make the mono version of the Inducer system — is that still so, even today, years later?
Thank you!
Sure, email Trance Audio to check
I’ve been using sound to get back to health , when I listen to music I’m always fascinated by the “click” (think funk guitarist , you hear a click then a tone ) I learn all my instruments not listening to tone but the click , original impact
Your body then synthesises sound from your click , not the instrument , contact mics pick this up which is why they I retest me
Sound travels 4.3 times faster in water than air , ithis is why I could “hear ” or more correctly feel sound a long time before my ears heard it (I do a lot of metronome practice) sounds funny my feet hear better than my ears , I’ve joined them together . Mine were broke .
I’m not yet into mics or synthesis but If you know what I’m talking about , I’m guessing using pure click non acoustic to synthesis with a synth might be interesting.
I’m relating sound / click to weight of instrument , I like the sound of heavy bangs , they work body better eg train on track ,
certainly, click is a crucial part of the attack of any percussive or impact sound…. but that is only a small part of the sound world – there are many many sounds with soft attack and no click…. But fascinating to think about, as with the when ‘dots become a line’ idea, beyond a certain frequency of clicks also becomes a tone… Which makes me think of insects, thei stridulation is perceived as a tone, but is made up of a dense stream of clicks… And then there is the whole 90s music genre of clicks & cuts 😉
Thank you for this great page! I just tried Blu-tack on the bottom of my Cortado mkII contact mic for the first time. Worked like a charm but now I wonder if you have any tips on removing the blu-tack from the mic when done? A thin layer is stuck like gum to the bottom of the contact mic. Thanks for any insight!
BluTak comes off very easily, never had an issue getting it off & more have had issues with it not being sticky enough, especially when dealing with dirty or rough surfaces
Only trying to learn about mics but very pleased to see the experimental contributions in the article videos and the pingback links.
I have some lamellophones, all made in Africa with various African tunings. Some Mbiras from including a new Nyunga Nyunga and a Karimba from Zimbabwe,some Likembes from Congo area, and others that I’m trying to find out about. The actuators are forged or recycled flattened steel or iron rods of different types, and the resonators are carved thick or thin hardwood boards or soundboxes. About half have metal buzzers, either wrapped around the tines, or bottle caps etc attached to the soundboard. One has bamboo tines and soundbox. The lamellophones, at least the ones from Zimbabwe, are tuned to produce overtones caused by changes in width and thickness along the length of each tine.
I’d like to be able to run them all through my guitar amp and pedals. Don’t want to mess them up though, one is a hundred years old.
I have one electric mbira built in Zim. It sounded weak plugged into the guitar amp but sounds OK with a v-twin tube pedal. It’s anything but tinny, it picks up the deeper overtones from the thick hardwood board but the higher metallic sounds don’t come through as well. Can’t hear the bottlecaps at all and they are part of the music. Figured it has a contact mike but don’t know.
I saw a mic at cold gold audio with alligator clip soldered to a piezo, that could be clipped to the bridge or tension bar of a lamellophone to pick up the metallic sound. Most of them have a place to attach the alligator clip. I wonder if those are tough enough to survive a lot of swapping between instruments in my home studio ? The resonant body and buzzer sounds are also important. Maybe something like a ceramic mic would work better, but I like that a contact mic would eliminate ambient noise. I thought of using magnetic guitar pickups, two needed for wider ones, but there is very little space for pickups under the tines. Those guitar tuner pickups that clamp to the headstock look rugged but I wonder if they are sensitive enough since they’re not designed for that.
hmmm really not sure – i have a Hugh Tracy mbira which has a pickup built in it, but it doesnt have the bottle top rattlers… But the problem using a contact mic to try & capture the sound of those rattlers will be how to place the contact mic so it is directly physically connected to the wood where they are hitting, and even then it will only ‘hear’ the rattles when they are connecting to the wood, not when they are rattling in free space (ie not touching the wood)
Another option could be to permanently mount a tiny lavalier mic on to the body, but it will act as a ‘normal’ microphone albeit it very close to the source of sound, so would be fine for recording but it would still have the issues of potential feedback when amplified… tricky! sorry I dont have much else to offer in the way of advice, other than searching to see what others have found works
I tried placing my ear on the soundboards of several lamellophones tonight to approximate the sound that would be picked up by a contact mic. I was surprised at how loud they all were. Also, if my ear was under the left side of the soundboard then the tines on that side would sound louder. Left side / right side didn’t make a noticeable difference if the instrument has an enclosed sound box instead of a solid board. The ones with bottlecaps all have solid sound boards – listening with an ear in contact with the board made the tines sound much louder but didn’t amplify the buzzers at all. On that instrument the bottlecaps are vibrating in mostly free space as you suggested, otherwise they wouldn’t vibrate. On the other hand, when I checked a sound box instrument with cylindrical metal rattles attached to the tines, between the bridge and tension rod, listening with the ear in contact did seem to amplify the buzzing, more so if my ear was against the top of the box.
Double post was unintentional, delete my Oct. 24 post if you like.
Off topic, I remember hiking near a railroad track years ago when a sound emanated from the tracks. I put my ear next to the track and heard a loud musical sound. A few minutes later a train appeared in the distance. Being seen messing around at the tracks might attract the wrong type of attention, but the result may be worth it.
Thats a good approach, pressing your ear to detect vibrations – I often just use my finger and if I can feel vibrations (even gently) then it is a good candidate for contact mic placement… The more difficult situation can be where there is too much vibration, and it becomes a challenge to reliably attach the contact mic without it either falling off, or dampening the very vibrations trying to capture….
re the railway line, I have heard of that phenomena before, and recreated it for a film years ago…. Sure wouldnt want to get caught up in listening, especially if a shinkansen/bullet train was approaching rapidly 😉
Hello! I am trying to build impedance matching pre-amp based on the reference you gave on the comment. One question is can the reference circuit apply to 12mm piezo? Also, would there need to be circuit adjusting, if I combine two piezos, such as https://www.bluestarmusic.com/Shadow-SH-720-Dual-Sensor-Small-Spot-Piezo-Pickup-wJack_p_2413.html
Thank you and I look forward to hearing from you!
Sorry I dont know the answer to either question – its a question for an electronics tech and you may just need to measure the impedance of those piezo elements to verify that circuit is suitable.Did you google for tech specs on them? Bluestar are just resellers, find the company who make them, the tech specs should state the impedance
Hello Tim,
You are right, I contacted and said they don’t have the specs. I will look for the tech specs + company who make them. Thank you!
Great article.
A simple aand cheap buffer/preamp for a piezo element is relatively easily build. For instance this might be a simple but effective solution:
http://www.till.com/articles/GuitarPreamp/
and
http://www.till.com/articles/PreampCable/
I’ve build several of these preamps and used them with piezo discs and it works fine.
Hans
years ago I blue tacked an eletret mic hard up to the wooden frame of a piano…the BT islolated the mic from outside sounds ie, direct contact only. This was a unit with its own 1.5 v battery . Unbeliebable quality and level with zero feedback and great tones from the timber
Hi,
Do you offer advertising space/article placement on musicofsound.co.nz?
If so, how much would it cost for an article placement with a link to a games website in the article?
No I don’t. But you already know this as you do not see any ads on this site, right?
Very interesting article. I love the activators picture 🙂
I recently intended recording sound fx with an AKG C411B sticked on a concrete barbecue pit which I was scraping with a metal rod.
Result was disappointing because of the microphone self noise floor.
On an other hand I doubt C411B is exactly a contact mic because it picks up slightly air sounds.
Also concrete isn’t going to be a very good transmitter of vibrations due to its weight & density… A good rule of thumb is to light palce your finger on an object and see if you feel vibrations with your finger. If not then a contact mic is likely also not going to pick up music. By comparison even a heavy piece of metal you will feel vibrations
Thanks for the tip !
Anyone have experience with the Radial Stagebug SB4? its specifically for piezo mics and supposedly has 10meg ohm impedance. maybe this can then go to a normal preamp?
Having performed a search on this page, it seem I have a unique (within reason) requirement: I race cars as a hobby and having watched many recordings of on-board car-cameras (with built-in mic’s), it is glaringly clear that often the sound (noise) is far from sexy. Wind is a big thing, but it doesn’t stop there; the frequency range that is recorded can be anything from too toppy to too lowwy (is that a word?) and also indistinct. My own camera doesn’t have a port for an external camera and am not interested in buying another, but as a relatively inexperienced DIY electronics fan I am interested in augmenting the experience and could cobble together my own cheap solution. As the engine is an opposed 4 cyl, I have also wondered whether I could “tune” the signal to taste (Ferrari comes to mind!). Ignoring that aspect, are there any insights for peizo (cheap and cheerful variety – I could make the pre-amp) placement? It would be great if I could pick up sound from other cars too when they go passed – I mean when I go passed them!
short answer: put your finger on it! wherever you think might be a candidate for interesting sound using a contact mic, lightly press and hold your thumb against it… do you feel the vibrations through your thumb? if so, then its definitely worth a try…
but its worth appreciating dynamics, eg compare the bridge of a violin with the firewall of a V8… is your thumb ok? not getting burnt? not getting shaken loose?
of course the only answer is to experiment.
try something simple & safe…
if that works, escalate it….
Hello,
Do you offer ad space (or sponsored posts) on musicofsound.co.nz ?
If so, what would you charge?
Thanks in advance,
Steve
Digital Content Zone Group
No.
Hi Tim- Amazing article, very informative. I just wanted to say I think it’s great you actually take the time to answer so many questions, and I really enjoyed your comments regarding advertising and redundant questions already covered in your article, funny shit. The sounds you have captured and quite stunning, keep it up
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Does anyone have experience with using a contact mic to amplify the chimes in a grandfather clock?
People use a single contact mic to pickup the sound of a piano, by attaching the contact mic to the bridge/frame the strings are attached to, so the same would apply to a grandfather clock. As per a previous reply: “Contact mic picks up vibrations – a good way to test a possible location is to lightly put your finger on it & if you can feel vibrations then put the mic there….”
A quick google says “Most chiming, weight-driven, mechanical grandfather clocks have 12 hammers and rods” so you are going to go put your finger on whatever those chimes are attached to, and see if you can feel vibrations, without dampening the chiming itself. Attach a contact mic there and listen. Try it in different positions, see what sounds best.
Amplifying that sound has nothing to do with contact mics. A contact mic provides a weak audio signal, which is amplified by its preamp. Then it is an audio signal which you can record or you can plug it into an amplifier & speaker or a mixing desk and an entire PA sound system if you want to…
Thanks for your info’ generosity Tim . there are some great tips here.
I have a very specific contact mic’ task that I’m aiming to solve with respect to
aeolian wind harps. Please consider the following.
I’m currently refining a wind harp design for a global weather & climate-change monitoring project that kicks off in half a dozen weather reporting stations situated here and on Pacific Island sites where weather and climate is an urgent issue . . ie more urgent than most are aware of.
The aim is for participants at each location to record video and audio responses via cellphones and to record wind harp audio via a contact mic, but getting the signal onto a cellphone & audio recording app that converts analogue to digital and captures the harmonic frequency band as accurately as possible is a tech’ challenge.
I will follow up some of your mic brand links to see what’s on offer by way of cellphone adaptors/ digi converter /pre-amp or whatever . .but if you are open to sharing any pointers or knowledge you have on this, it would be appreciated hugely.
thanks.. . feel free to call if easier.
Phil Dadson
0226357119
Hi Phil (I don’t use phones, but I will email you)
My first thought was that the two models I use are not applicable due to (1) cost, especially for multiples and (2) powering will be an issue (BB needs 48V phantom power and TA needs 2x9V batteries). But the wind harps that I have heard tended to have spectrum dominated by higher frequencies, so maybe a little bass loss due to not using an active preamp may not be a major issue. There are many options for cheap peizo contact mics, whether you make them yourself or source them. A few that spring to mind:
Jez Riley
https://jezrileyfrench.co.uk/contact-microphones.php
Cold Gold
https://www.contactmicrophones.com
Ideally you would still want to match impedance, but the far bigger issue is how to get a contact mic signal or even line level from a preamp into a cell phone. I really have no idea sorry, it is not an issue I have ever had to consider. Anyone can point their phone at an object and record video with sound, but getting line level audio into a phone will require a preamp but that also opens all sorts of other potential issues eg phones by default record from their own mic. So every single user would have to plug into some kind of preamp, AND change their phone or app settings. That does not seem viable to me.
The only practical suggestion I have would be some kind of acoustic amplifier or resonator that makes the sounds audible for normal cellphone capture. I saw a youtube vid of someone bowing a long wire fence, and they used one of those giant plastic water containers as a resonator, which amplified the audio enough to be heard clearly without any electronics involved. Maybe this could be built into the design of the harp? This vid (from the wind on mic noise, presumably recorded with a phone)
https://www.youtube.com/watch?v=W-wRdLjJzA8&t=5s
bestest regards
Tim
Hey Tim! Trance Audio released a stereo phantom-powered system eventually.
I want to buy a contact mic(s) for sound design purposes. What would you suggest?
Indeed. I’ve been using a stereo Trance Audio contact mic for the last 5+ years. I find it more robust than the BB – I have broken maybe 4 or 5 of the BB mic elements. So to answer your question it depends what you’re recording. If its nice clean musical instruments the BB system works great & sounds great. But I mainly use the TA system now as its not so fragile & doesn’t break… YMMV
Thanks for the reply.
So you`re using The Inducer or the new Amulet System?
I first got an Inducer in 2012 as per the article you are commenting on. I got the new stereo system as soon as it became available, don’t remember when but I’ve had it a few years now
Got you. Have you noticed any difference in terms of audio quality between them?
I got an explanation from the Trance Audio why the Inducer is coming without phantom power.
“Unfortunately, phantom power is not an option for the Inducer.
Our preamps are specifically designed to be direct coupled (no capacitors in the
actual audio path) which allows us to create the cleanest and lowest distortion
devices for the preamps. To do this requires that we have a balanced voltage supply,
with both positive and negative voltage sources available. To accomplish this for our
Amulet M phantom powered systems for guitar, we use a specialized circuit to create
the required negative voltages from the positive only voltage available via phantom power.
This circuit operates above the audio frequency at around 22-24khz, so any residual
interference it causes is out of the typical audio band.
In SFX work however, source recordings are sometimes pitched down for certain effects,
which can then make this interference audible. This is the reason we instead use a second
9 volt battery to supply a completely clean source of negative voltage for the Inducer system”
P.S. sorry for a lot of words
I’ve never compared them. Yes I know about the lack of phantom power.
Thank you! And this article is amazing! That`s exactly I was looking for.
Super helpful article! Curious if you have any recommendations for recording a cat purring — I know I’ll need a mic with fairly strong low-end response, and at least somewhat durable (cats are sometimes unpredictable 😅). Is there anything I should keep in mind when looking for a contact mic/doing these recordings?
How will you attach the contact mic to the cat? You’d have to shave the cat but then how do you stick a contact mic to skin without harming it? I’d likely use a shotgun mic, not a contact mic…
HA, I’m imagining the mic being held to a cat that’s laying down, not glueing it on or anything. Another possibility is fixing the mic inside a cat harness (like this http://www.kittyholster.com/photos.html ) so it’s held taught against the chest. I hadn’t considered the fur being an issue, though — would too much of the vibration be lost for a contact mic to pick it up?
Depends on the cat, how much fur etc… Contact mic needs solid direct connection to a vibration source, otherwise you will be recording the sound of the contact mic kocking & rattling around, rather than the clean transferrence of vibration… Experimenting is the only way to know.
One tip: you really need to monitor the contact mic recordings in real time. The difference between normal audio & contact mic is startling – its always good to record both if you can. With a normal mic eg recording ambiences I can ‘set & forget it’ but with contact mic, if I don’t constantly listen to what they are capturing, then I cannot be sure what I am recording. If a contact mic detaches even a few mm, the sound is lost. So eg if you press a contact mic against the cat with your finger, you’ll want to be listening to that so you can vary the placement & pressure etc based on results.