Welcome, Guest
Username: Password: Remember me

TOPIC: Unwanted volume boost

Unwanted volume boost 2 years 2 months ago #981

  • ucfanrg
  • ucfanrg's Avatar
  • OFFLINE
  • New Member
  • Posts: 12
  • Thank you received: 7
  • Karma: 2
Hi there!

I've completed the pedalshield for STM32 (without Jumper1 it sounds better) and I'm pretty sure my circuit is the same as the schematics.
I've tested it and the only things that bugs me (appart from the noise, because im on a breadboard) is that the volume is boosted, which cause it to clip a little bit.

With the clean guitar example, without the volume programmed, I do a direct adc read to dac write. I've tried turning the RV1 (500k) pot all the way down but the signal is still 25% louder.
I can achieve a good result by turning down the volume knob on my guitar, but it's not ideal.

Is that a normal problem? Am I missing a part or can I add a part to cancel the boost?

Thanks!
The administrator has disabled public write access.

Unwanted volume boost 2 years 2 months ago #982

  • Ray
  • Ray's Avatar
  • OFFLINE
  • Moderator
  • Posts: 692
  • Thank you received: 146
  • Karma: 41
This volume boost is not a bug, it is the default "behavior" of the pedal.
In order to have an optimal ADC span I recommend you to have the RV1 pot as "high" as possible so you will digitalize a good analog signal.
Then, after the DSP, the DACs will work in parallel and they usually general an output signal that is louder than the input.

The best way to manage this volume change in case that it bothers you is to include the code
  //Add volume feature with POT2
  out_DAC0=map(in_ADC0,0,4095,1, "your level here");
  out_DAC1=map(in_ADC1,0,4095,1,"your level here");
right before the DAC writing, where "your level here" should be a number between 1 and 4095, maybe around 3000 is good for you (try higher or lower depending on your guitar pickups level)
The administrator has disabled public write access.

Unwanted volume boost 2 years 2 months ago #983

  • ucfanrg
  • ucfanrg's Avatar
  • OFFLINE
  • New Member
  • Posts: 12
  • Thank you received: 7
  • Karma: 2
I've tried this solution before but the problem is that the sound clips before going in the ADC. Reducing the volume on the software parts keeps the clipping. If it is the normal behavior of the pedal, I will work with it (reducing the volume pot of my guitar).

Thank you!
The administrator has disabled public write access.

Unwanted volume boost 2 years 2 months ago #984

  • BowDown
  • BowDown's Avatar
  • OFFLINE
  • Senior Member
  • Posts: 55
  • Thank you received: 6
  • Karma: 2
Hi BloodStyle!
Thanks a lot for your efforts!
Do you plan on releasing the code/schematics after you are done?
The administrator has disabled public write access.

Unwanted volume boost 2 years 2 months ago #986

  • ucfanrg
  • ucfanrg's Avatar
  • OFFLINE
  • New Member
  • Posts: 12
  • Thank you received: 7
  • Karma: 2
For sure!

Once everything is decided on the schematics, I'll post something similar to what Electrosmash has done.

On the software side, I think the first effect I want to make is a Noise Supressor (Noise Gate), which will help a lot I think.
The administrator has disabled public write access.
The following user(s) said Thank You: BowDown

Unwanted volume boost 2 years 2 months ago #987

  • BowDown
  • BowDown's Avatar
  • OFFLINE
  • Senior Member
  • Posts: 55
  • Thank you received: 6
  • Karma: 2
Thanks a lot!
The administrator has disabled public write access.
Time to create page: 0.298 seconds
Powered by Kunena Forum
Joomla SEF URLs by Artio