Adding 23A1024 RAM chip to audio board for "Reverb" effect?

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mcooi77

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I'm working on a project similar to Blackaddr: a guitar effects box. I'm using a Teensy 3.2, I ordered one (and an audio board) after watching the tutorial video.

I've found nearly similar threads on these forums asking about RAM and the "reverb" effect in the Audio Library. Despite reading through several times, I am still unclear whether adding a RAM chip (as suggested on the audio board page) will free more RAM to use effects like "reverb" or "chorus" etc.. From what I gleaned, the optional RAM chip doesn't actually do anything, in which case, I'm terribly confused and would love to learn why adding a RAM chip won't increase the number of blocks available to store a 1-2s reverb.

Sidenote: I tried using the audio library "reverb" effect for a delay of only 0.2s and I got the following error (which I kind of expected if I understand that it's telling me the Teensy 3.2 doesn't have enough free space to use this effect.)

Code:
d:/program files/arduino/hardware/tools/arm/bin/../lib/gcc/arm-none-eabi/5.4.1/../../../../arm-none-eabi/bin/ld.exe: C:\Users\Matt\AppData\Local\Temp\arduino_build_433202/sketch_oct28a.ino.elf section `.bss' will not fit in region `RAM'

d:/program files/arduino/hardware/tools/arm/bin/../lib/gcc/arm-none-eabi/5.4.1/../../../../arm-none-eabi/bin/ld.exe: region `RAM' overflowed by 23532 bytes

collect2.exe: error: ld returned 1 exit status

Multiple libraries were found for "SD.h"
 Used: D:\Program Files\Arduino\hardware\teensy\avr\libraries\SD
 Not used: D:\Program Files\Arduino\libraries\SD
Error compiling for board Teensy 3.2 / 3.1.
 
I am still unclear whether adding a RAM chip (as suggested on the audio board page) will free more RAM to use effects like "reverb" or "chorus" etc..

Simply adding the RAM chip will not do anything at all. It is *not* automatically detected and used.

Currently only the DelayExt object uses the RAM chip. That's it. Nothing else makes use of that 23LC1024 chip.

So, if you are using a delay line in your audio system, and if you change it from the regular delay to delayext, then you will free up RAM for other uses. Currently that is the only case where the 23LC1024 helps.

At some point in the future, there's likely to be play & record objects for that chip, so you can use it like a sampler. But those have not yet been written, so unless you intend to dive into the audio library code and write these (or something else) yourself, the only way to make use of the RAM chip is with the external delay object.
 
Okay, that really clears things up. Thank you, Paul!

You made a comment in some other similar thread from years ago, advising the poster to just opt for a Teensy 3.5 or 3.6 instead of working through such a headache--that makes sense now.
 
@Paul, Thanks for being taking the time to answer newbie questions, I try to do my researching before asking. But as the implementer for the "Reverb" effect to the audio library, what is your hardware recommendation for using this "effect" as part of a larger project? I only have a basic understanding of how the Teensy RAM does not function like PC RAM, but by this thought: sketch-code will either work or it won't depending on how much memory you allocate, so then is it safe to say that an overflow of roughly 24k, plus the Teensy 3.2 64k means I should expect to use hardware with no less than 90-100k memory (accounting for very small overhead)?
 
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