Focus Fidelity Filter Designer

[Jean-Marie]

The length of the filter, number of taps generated by FFFD is selectable, choosing the 0.743/0.683 seconds option (on the view filter screen) will mean it generates 65536 taps for sample rates of 88200 and 96000. The generated files for sample rates 176400 and 192000 will be twice as many taps, 44100 and 48000 half as many.
Modern PCs can EASILY run filters of these lengths at these sample rates doing 64-bit double-precision math.

David - Thanks for the information, my learning curve continues! 

To put the above into perspective, I have actually checked the CPU usage of my PC running HQPlayer upsampling to 24/192 and using 192000 sample rate Focus Fidelity Convolutions.

The load on the PC seems to be surprisingly trivial, with HQPlayer requiring less than 1% CPU usage. (it actually flicks between 0.3% and 0.4%, occasionally reaching 0.5%) This is with an i9-9900K PC.

In my earlier post I was asking is there was a "simple hardware solution will run 65536 tap length FIR filters". Here I was thinking about a miniDSP style product rather than a PC. So something that you could conceivably place on a hifi rack between a turntable / phono stage and the digital input of the DAC / Amp, and hence get the benefit of DRC convolutions with a turntable as source. Someone had mentioned to me that there was product that could do this, miniDSP "OpenDRC". This sounded promising, but I have subsequently checked this out, and the OpenDRC is limited to a relatively lowly sounding 6148 taps. Maybe one day miniDSP will bring out a project that is a little more powerful?

Also, the relatively low CPU usage of HQPlayer with convolutions makes me wonder if the Devialet CI board is actually capable of running convolutions like this. OK, the CI board does not have an i9-9900K processor, but neither would it need one based on the very low CPU usage that the convolutions seem to require.

Just a thought.

I am quite convinced that the embedded processing capacity of the DSPs in the Devialet is sufficient for executing those filters. After all this is just bread and butter for those kind of DSP. 

I think that the real ‘issue’ from Devialet’s perspective is the interface that would need to be offered, and the potential for problems and troubleshooting that they could have to face from a support perspective. 

My two cents,

Jean-Marie