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Score following with piezos and contact microphones

Antescofo
#1

Hello,
I compared the Antescofo behavior between two contact pickups mounted on each side of an electric cello bridge (Yamaha SVC silent).
The first one is an AKG-C411 (electrostatic contact microphone with fantom power).
The second one is a cheap piezo pickup (from the brand IMELOD).

I’m really puzzled with the score following results I get from the same recording with these two source signals.
As you’ll notice it in the provided Max patch, the score following is quite good with the AKG-C411 whereas quite bad with the piezo IMELOD.
I suppose it may be due to the problems of electromagnetical interferences, that are known to be difficult to reduce with piezos pickups.
This permanent residual noise may prevent Antescofo from identifying the notes in a correct way.
I tried to reduce it with a high-pass filter cutting the 50 Hz of electric sector, but it didn’t improve the result.
So would it mean that Antescofo cannot work correctly with the contact piezo pickups in general ?

Regarding the AKG, it should be noticed that a residual noise also exists in the signal, like a continuous blow, but it doesn’t seem to perturbate a lot the audio pitch tracking…
The only problem I reported with Antescofo following the AKG is a tendency to anticipate a little bit more by switching to the following note before the end of the current one.
Maybe an idea to improve that ?

#2

Hello @jojocello and thanks for providing a clean working example.

The problem with the piezo (as far as I can “hear” it) comes from its frequency response. If AudioSculpt was working on my machine I bet I could even “see” it! :slight_smile: The Piezo IMELOD sounds filtered and I assume that it’s because it’s a piezo!

In general, I do not recommend using piezo type microphones for score following as they “pick up” unuseful info from the instrument body for a score follower.

Now the AKG is a Pickup mic. That’s what you want! It’s actually picking up the sound and it doesn’t “sound filtered”.

You don’t necessarily need expensive microphones for score following! Anything that can pickup “sound” and not too much noise.

Hope this helps.

#3

Hello Arshia,
Thanks you very much for this answer.
It confirms what I thought : piezo pickups are not relevant source signals for score following.
So I will spare more time now :sweat_smile:

As a little sum up, it seems that a suitable source signal for Antescofo should be:

  1. Non-filtered (to preserve a maximum of details of the instrumental frequency response)
  2. Non-noisy (cleaned up from every electromagnetic interference)

Thanks again for your help.
Jocelyn

#4

:+1:
and maybe some other criteria:
3. Not necessarily an expensive mic! :slight_smile:
4. Try to isolate your instrument as much as possible from your live electronics: e.g. avoid pointing your Monitor to the mic!