Sample playback speed from different sources

[JotaEfe13]

Hi. After some search, I have not found how different playback sources compare to each other regarding speed. Are there any benchmarks? I understand that there are some factors to take into account, such as the chip specs, different configurations and buffering strategies, but generally, would this be correct?

internal RAM > PSRAM > Flash > SD

I am trying to find the best way to play up to 16 simultaneous samples of up to 1MB in a reliable manner and with minimum latency.

 

[h4yn0nnym0u5e]

Yes, that assessment of the relative memory speeds is broadly correct; there’s probably little difference between PSRAM and Flash, if both are fitted to the QPI pads on Teensy 4.1.

If 16 samples of 1Mbyte is a definite upper limit then using 2x PSRAM is the simplest way to go. With Teensyduino 1.60 (currently in beta) there will be support for 16MByte PSRAM parts, though it’s unclear what hardware availability will be like.

If you might need more flexibility, then I’ve done an SD playback library which can achieve minimal latency (as good as samples entirely in memory). PSRAM is still useful as buffer memory, and is 100% required for the 88-note x 3 level piano example!

 

[JotaEfe13]

Thank you h4yn0nnym0u5e, I think then I will go for PSRAM, but I will definitely have a look at your lib, as I am also interested in playing from SD card for a preview of the samples.