I'm posting here for more visibility even though I did the testing in JRiver 23 for Windows. I suspect this happens in JRiver 25 as well since I've never seen a changelog that mentions improved audio performance.
I'm using JRiver's DSP studio to make an active speaker, and it looks like I have to stop using it. This post is to inform JRiver engineers of the bugs I've seen.
This is the loopback measurement using JRiver's WDM + DSP Studio, with a single 48dB/octave high pass filter at 30Hz. There are multiple problems.
1. The clearest problem is the strange low shelf filter around 700Hz. After multiple testing, this is an artifact caused by the high pass filter. What's interesting is that if I use a VST that does the same high pass filter, it shows the exact same problem. This seems to indicate a numerical stability problem in JRiver's audio pipeline.
2. Look at the wiggles in the measurement. This should not happen at all. A loopback measurement with Equalizer APO shows a clean flat line.
3. There is a slight rise in treble for some reason. Again, I think this is due to numerical instability
Other audio bugs.
1. The subwoofer limiter has lots of problems too, and that's been documented on this forum before, but no action was taken.
2. Every time the FIR files are changed, the first 30 seconds are kind of off, and then sound will jump 1-2 times and get back into proper timing. Also, the delay is huge, almost exactly 4x longer than it should be. But it seems JRiver is aware of this and corrects it properly when playing videos within JRiver.
I've suspected JRiver has sound quality issues for some time now. I've verified it with double blind listening tests. The difference is quite obvious compared to Equalizer APO. I suspect the problems are non linear as well. There's clearly something going on with the DSP processing in JRiver. For now, I'm moving to Equalizer APO. I hope the engineering team can find it.
