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Topic: Midi - Musical Instrument Shield - Volume Problem (Read 2724 times) previous topic - next topic

RufusTheFirefly

Hi, beginner here.  I'm using a joystick to play Midi notes with an arduino and a Musical Instrument Shield (https://www.sparkfun.com/products/10587) but the volume is too low.  I want to be able to play over an acoustic guitar so I need a pretty strong sound. 

It's so weak with just the shield setup and a speaker that I have to hold the speaker up against my ear to hear it at all.

At first I checked the internal volume, but I have the midi volume set at 120 out of 127.  If there's any other way to increase the internal volume though I'd love to hear it.

So then I used this Mono Audio Amp Breakout board (https://www.sparkfun.com/products/11044) powered with 5v and a 8 ohm, 0.5 watt speaker to amplify it some.  Now I don't need to hold it against my ear but it's still very weak.  I'd like it to be as much as 10x louder then it is now with the small amp.

Does anyone have any ideas on how to increase the volume dramatically or a suggestion for a good amp to build that wouldn't destroy my circuit?  Nothing too crazy, I am a beginner after all.  Also, could I hook this up to a regular guitar amp or would that cause a problem?

Thanks for the help!

semicolo

what kind of midi commands are you sending? maybe you set the note on velocity too low

RufusTheFirefly

I've been setting the velocity to 60, which I took to be medium.

semicolo

You could use a higher velocity, if the volume control is logarithmic it can make a huge difference.
If it's still not enough you can try to boost the gain of your amplifier
https://www.sparkfun.com/tutorials/392#gain_resistors

RufusTheFirefly

Sorry forgot to mention I already boosted the gain/volume with a pair of 10K resistors I had around.  That did make a difference.

Also, following your suggestion, I tried it with the velocity at 90 and it was a little louder, thanks.

I'm still looking for a way to dramatically increase the volume though.  While both of these things have helped, they have been tweaks.  I need something that will increase the volume ten fold.  At this point I'm assuming I'll have to build another amp but maybe someone could point me to one that's much more powerful and wouldn't wreck the circuit?

Would this work if I plugged it into a guitar amp (changing it to 1/4 output pin)?

Thanks again

semicolo

#5
Apr 08, 2013, 05:22 pm Last Edit: Apr 08, 2013, 05:29 pm by semicolo Reason: 1
There must be something wrong somewhere, with an half watt speaker you should hear the sound quite well.

Maybe you damaged the vs1053 output, I can't help more since I don't have this device.

RufusTheFirefly

I think you're right that something must be damaged.  If it helps, when I plug headphones into the Musical Instrument Shield, the sound is good.  It's only when I try to use speakers that the problem arises.

Any ideas on tests I can run to try and figure this out?

Thanks


semicolo

Looks like the instrument shield is ok and it's quite normal that it's not able to drive a speaker withouth an amplifier.

Does your amp works well if you plug it to an mp3 player/cell phone?

You can try plugging the instrument shield in a guitar amp.

RufusTheFirefly

I have it working pretty well now.  Thanks semicolo!  It was, as you suggested, just a matter of maximizing the velocity (127) and volume in the midi commands and adding bigger resistors to increase the volume/gain.

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