Thank you. I forgot to add, I have a number of other things which may cause latency to be worse than normal.
- JRiver hosts the convolution files for my audio system. It creates the crossover. So it takes a 2ch input and splits it into 8 channels. This goes into an 8ch DAC and then to my 4 way speaker system. I wondered if JRiver's convolver is a little bit slow, so I got JRiver to output 2ch to Acourate Convolver. I get the same result. I think the FIR filters are adding latency.
- I have been upsampling to 192kHz because I get a benefit of improvement in SINAD from -110dB at 44.1kHz to -118dB at 192kHz. Changing this back to 44.1kHz has lowered the latency. Interestingly, if I get JRiver to perform convolution at 192kHz, I get audio stuttering and dropouts, despite CPU usage at 20%. If I get JRiver to upsample to 192kHz and send that to Acourate Convolver, it plays flawlessly.
- I have already been using the BubbleUPNP settings and JRiver settings you recommended. In fact, I was using 5ms buffering in JRiver.
For now, I am going to point the blame at the long FIR filters and the 192kHz upsampling. I can't do anything about the long FIR filters, it took me a lot of effort to make them and they sound excellent - well worth the cost in latency (if that is the cause). But the 44.1kHz -> 192kHz upsampling I can do without, so I have dropped it back to 44.1kHz.
I wonder if there is an explanation for the stuttering and dropouts when I upsample to 192kHz and apply convolution in JRiver instead of Acourate convolver. I mean, CPU usage is only 20% ...