[6.42] Inconsistent ReaDelay sound with diff. sample rates

[thenickname]

ReaDelay sounds significantly different depending on wether Reaper / the audio interface is set to 48khz or 96khz sample rate (see provided example file). That alone is strange. However, even more strange is Reapers track-freezing and rendering behavior. Depending on the sample rate set in reaper settings, frozen tracks and the rendered output will also sound differently. The freezing and rendering behaviors are inconsistent and can produce two different sounding files even though the export settings are exactly the same. The audible differences are not subtle, but quite noticable.

The bug has two parts:
1. ReaDelay sounds significantly different when used at 48khz and at 96khz
2. Freezing tracks and exporting/rendering behaves inconsistently and produces different sounding results depending on the sample rate of the audio interface


Steps to reproduce while working / listening in reaper:
1. add a ReaDelay plugin to a track
2. set Reaper (respectively sound card / audio interface) to 96khz
3. listen to the ReaDelay sound and note how it sounds (produces a lot of high end / or a more pronounced delay effect)
4. set Reaper (respectively sound card / audio interface) to 48khz
5. listen to the ReaDelay track again and note the dull sounding result / as if a significant portion of the high frequencies just vanished or the delay is much weaker

Steps to reproduce during freezing of tracks:
using the same overall setup as descibed above:
1. set Reaper (respectively sound card / audio interface) to 96khz
2. freeze track and listen to the result: Note the clear sound with lots of high end
3. set Reaper (respectively sound card / audio interface) to 48khz
4. freeze track and listen to the result: Note the dull sound.
5. Once the track is frozen, switching the audio interface from 48khz to 96khz won't make an audible difference for the frozen tracks. One will sound dull and the other will appear to have much more high end (regardless of current sample rate setting in Reaper)

Steps to reproduce during rendering:
using the same overall setup as described above:
1. set Reaper (respectively sound card / audio interface) to 96khz
2. render a .wav with 48khz and note the dull sound
3. render a .wav with 96khz and note the clearer sound
4. before rendering, freeze the track (while Reaper is set to 96khz)
5. render a .wav with 48khz and note the CLEARER sound (!)


Expected:
- ReaDelay does not produce vastly different results in 48khz and 96khz
- when freezing a track or exporting a file targeted for 48khz, the rendered audio file will sound the same, regardless of whether Reaper / the audio interface uses 48khz or 96khz sample rate at the time of export

Actual:
- while working in reaper, ReaDelay will sound significantly different depending on sample rate
- the render result depends on both the render settings and the currently used sample rate in the audio interface
- frozen tracks behave differently during rendering compared to "live" tracks

Also: Which of the two ReaDelay outputs is the "correct" one? Is it the 48khz version or the 96khz version?

## Example file
https://drive.google.com/file/d/1Dv9...ew?usp=sharing

## Info / specs
- MacBook Air (M1, 2020), 16GB RAM
- macOS Monterey 12.0.1
- Reaper ARM beta v6.42
- using MOTU M2 audio interface or internal sound card (makes no difference)

[thenickname]

one additional note: To clearly hear the significant difference between both frozen tracks, unmute them in the provided example file and phase invert one of the tracks. Ideally, the two signals would cancel out. But they surely don't.

[Justin]

Ah, it looks like the filters do not handle changing samplerates properly. Fixing!

[thenickname]

wow that was quick, thank you!