Monday, September 11, 2006


Can anyone explain what bypass and hold do exactly?
I guess I forgot...

And one more question,
My feedback level is only 0.25 max per channel, and my output level is 0.5 max per channel. But if I input some signal with 0.25 feedback and 0.5 output, I get feedback getting louder and louder. My gain inspecters are set to 128, which shouldn't add any amplitude.

Does anyone know why it's happening??


Blogger Colin Holter said...

"Bypass" turns the delay off as long as the toggle is on. I made mine by assigning a toggle to a) set the feedback to 0 and b) store a fedback value immediately before it's set to 0 that is recalled when the Bypass toggle is hit again (i.e. turned off). It might have been more elegant to just disable the adc; did anyone else do it that way?

"Hold" keeps new signals from entering the delay line and old signals from decaying - in other words, Hold needs the feedback to be 1 (i.e. no decay) and the input to be disabled (i.e. no new signals added to the delay line). Implicit here again is that you'd store the old feedback so it can be recalled when you turn the Hold off.

As for the output issue: If your output is set up like mine, you're not dealing with maximum levels per se but with multipliers; your output has the potential to reach any level, which is why your feedback gets louder and louder - there's no ceiling, just a graded floor (bad analogy, I know). There may be an easy solution to this one, but I don't know it - I just keep an eye on my feedback level and try to avoid situations that might result in deafness.

7:09 AM, September 11, 2006  
Blogger Juri said...

I guess if we use cardioid microphone facing away from the speaker, the feedback wouldn't get louder as long as the feedback level is set equal or lower than 1..(but I'm not sure) Anyway, thanks for your comment, but I don't understand your graded floor analogy. Sorry about that~!

7:17 PM, September 11, 2006  
Blogger Steve Taylor said...

Hmm. If you multiply your signal by a number less than 1, it will always get softer (it does add to the sound already present, so if your source signal is really loud you need to lower the feedback). You may want to double check that all your wires are connected correctly.

7:45 PM, September 11, 2006  
Blogger Juri said...

I guess it's my laptop mic getting feedback from its speakers. I found out that it doesn't get louder when I use headphones.

10:49 PM, September 11, 2006  
Blogger Steve Taylor said...

Yes, you have to plug in your headphones - that built-in speaker feedback is nasty, I know it well!

10:54 PM, September 11, 2006  

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