Has anyone had experience using Sigma in connection with long L/R audio delays, on the order of 10 to 12 seconds? Far in excess of what can be done internally, but any ideas how to implement this simply and suggestions for memory parts?
Nothing is ever (that) easy. Finally resolved with lots of RAM and a PIC to run it.
I was pulled into several high-priority, time-critical projects at work over the past few weeks and unfortunately I had to de-prioritize my participation in the forum as a result. So, I apologize for making you wait so long for an answer. I am going to try to respond to everybody's questions within the next few days.
There was, at one time, an IC from a Japanese audio company - perhaps Yamaha - that I found floating around on the internet. It had an I2S input and an I2S output, and its sole function was to act as a delay line. However, I went searching for the device recently when a customer asked about it, and I was unable to find a trace of it anywhere. I fear that the device has become obsolete and is out of production.
The only remedy I can think of would be to use a more general purpose like a Sharc or Blackfin (or, of course, DSP offerings from other companies), because they typically have some kind of advanced memory interface that will allow them to hook up to external RAM for extremely long delay times.
Just happened to take a look at a similar device this morning, Texas TPA5050 ... but if I remember well it has only 170 ms of delay.
At CD audio sampling speed for 10 seconds you will need a very large memory, and I think the only way to go is an Arm microcontroller with a large enough RAM bank.
Retrieving data ...