[sdiy] Stereo Audio CODEC ICs

[Seb Francis]

Ingo Debus wrote:

>
> Am 28.01.2006 um 22:45 schrieb Seb Francis:
>
>> Yeah, I assumed as much.  Luckily this is what I want for my  
>> application.  I want to keep the sound quality the same while  
>> varying the delay time, so I will do this by changing the buffer  
>> size in software not the clock rate.
>
>
> Changing the buffer size is ok if you want a fixed delay. If you want  
> to modulate the delay time in real-time for flanging, chorus etc it's  
> much better to have separate read and write pointers and change the  
> offset between the two (and have a fixed buffer size all the time).  
> Imagine what happens when you suddenly increase the buffer size: you  
> might play back samples that are hours old, or even uninitialised.
>
> Using two pointers shouldn't be too difficult if the thing is done in  
> software.
>
I do want just a fixed delay .. but even so it would be preferable if 
the delay time can be changed without major glitches.

I hadn't actually thought of the details of the software yet, but what 
you say makes perfect sense .. having a read and write pointer both 
looping around the total buffer, and change the relative position of the 
read pointer when the delay time changes.

Seb