Tuning with a contact microphone

Frank Illenberger

Inspired by a post on the pianoworld forum, I started experimenting using a cheap Korg CM-300 contact microphone for directly picking up the sound from a soundboard rib.

I used a batteryless iRig HD 2 at full gain to connect the Korg CM-300 to my iPhone. I tried it on an upright, but it should similarly work on a grand.

So this could be a relatively cheap solution for somebody who wants to tune in very loud environments. The Korg CM-300 costs 12€ and the iRig 79€. An even cheaper alternative could be to use a TC-Helicon Go Solo instead of the iRig, which is only 39€, but I have not tried it yet.

Burkhard

Frank Illenberger Interesting. That could save your day.
I have already wished for something like this a few times.

For example, at open air events or when the stage workers make noise during the mood. What would bother me would be the additional cables.
Couldn’t you somehow use the Apple Air Pods Pro as a microphone?

Burkhard

I just recorded something with the Voice Memos app. It works when you open the case of the Air Pods Pro and use it as a microphone.

Then this should also work with Pianoscope??

Frank Illenberger

Burkhard AirPods are a good idea. Let's hope that their sample rate is high enough for piano tuning purposes. I will check this.

Frank Illenberger

Burkhard Today, I experimented with allowing pianoscope to get the audio input from a pair of AirPods. In principle, it works, but I doubt that it will help to be able to tune in a loud environment. To achieve this, one would need to embed the AirPods on one side inside a sound insulating material and on the other side put them in direct contact with the soundboard. A contact microphone clamped to a soundboard rib is far more resilient against background noise because it does not pick up sound from the air but only from body vibrations. In principle, it is possible to create a wireless setup with a Korg CM-300. One would need to connect it with a bluetooth transmitter.

Burkhard

Hello Frank. You’re right. Unfortunately, the AirPodsPro are not suitable for absorbing loud noise. Too bad, because I have the things with me all the time.

The Korg CM-300 makes much more sense.

I also experimented a little. Just for Fun…..I still had a few Lightning-Headphones lying around. It actually works. I was able to get a stable display despite loud radio music. 😆

Frank Illenberger

Burkhard Did you also clamp its microphone against a soundboard rib? The cable seems a little bit short for it.

navindra

Burkhard Thank you for this! I have the 3.5 mm version of these earphones and it took your post to realize that these work quite well as a sort of contact mic. I simply tape the mic portion down on the piano and it helps a lot with getting reliable readings in the high treble.

Burkhard

No, I only attached the microphone to the housing.

Frank Illenberger

Burkhard Can you make a photo of the setup?

Burkhard

This was just a short test of whether it basically works.

I clean up and try to tune the piano....

Burkhard

@Frank Illenberger Is it possible with the iRig HD2 to have the signal simultaneously in the app and in headphones?

Frank Illenberger

Burkhard The iRig always routes the audio output of the iPhone/iPad to the headphone jack. So to monitor the microphone input on the headphones, I would need to implement a live monitoring switch inside pianoscope, so that the apps mirros the input signal to the output. This would be some work but possible.

Burkhard

Frank Illenberger Then it would be possible for the tuner and the app to hide a noisy environment? I would love to try it out.

Could you also get Pianoscope to send the audio signal via the AirPodsPro? Then you could use noise cancelling....

Rick

Wouldn’t the noise cancelling cancel the piano as well? Is this all necessary?

Frank Illenberger

Rick You would be hearing everything the device mic is picking up, but every direct noise to your ears would be blocked. So this would sound like putting your ear very close to the piano. I don't know if this is necessary as I have never tuned in a loud environment.

Burkhard

Frank Illenberger

It is certainly not the everyday life of a piano tuner. But every now and then it would be very useful.
One or the other reason comes to mind.
Schools - kindergartens - churches (aftertaste) - open air - audience in the room - room attendants in the theater - sound checks - stage workers - ect.

Rick

I use -17dB custom made earplugs when tuning. In noisy environments I just put my head closer to the piano.

Stefan Borowicz

Reviving this thread!

I was doing floor tunings in a local piano store when a customer came in and started playing different instruments around me which essentially stopped me in my tracks from completing my tuning...and then I remembered reading this thread and thought this might be the solution.

Frank, do you feel the hardware you mentioned worked well enough to use this with accuracy? If I understand this setup correctly, absent the ability to have simultaneous monitoring via earbuds, you need to rely on the visual display? I find I use pianoscope to tune one string and then aurally tune the others to it—it would be really valuable to be able to continue this method in a noisy environment using the contact mic and earbuds.

Frank Illenberger

I don't have much experience with this technique. I tried it once and it worked nicely. The accuracy should not be a problem. It should be possible to monitor the audio picked up by the contact mic through the earbuds, but I need to write some code for that. I will definitely put that on my list of things to try but I cannot promise you a release date.

Burkhard

Frank Illenberger

Hello Frank,
Did you continue to pursue this thought?
Today I had the pleasure of fighting against 2 vacuum cleaners.
In order to make clean unison in noisy surroundings, it would be a great help.

Stefan Borowicz

I just received my iRig HD2 and Korg CM-300 contact mic and tried it on my grand at home and it seems to work well so far. I will be tuning pianos on a couple of cruise ships over the next couple of days (which can be very noisy, distracting environments with people milling about) and will test it in the field to see how this goes. Cautiously optimistic but excited about the possibilities this could unlock.