Search found 59 matches

by robiwan
Wed Jul 12, 2017 8:23 pm
Forum: Stereo soundcard for the Raspberry Pi
Topic: Lowest possible latency
Replies: 42
Views: 20456

Re: Lowest possible latency

I have used Eigen before, so will probably use that as the front-end for FFTs, so C/C++ it is :) Alas, I'm not very proficient in Linux/ALSA, so the plugin class certainly looks interesting. It's possible to create a standalone SO to load into ALSA with it ? Although, the plugin should be very simpl...
by robiwan
Wed Jul 12, 2017 7:49 pm
Forum: Stereo soundcard for the Raspberry Pi
Topic: Lowest possible latency
Replies: 42
Views: 20456

Re: Lowest possible latency

It is for a room correction application, so 0.3 to 0.5 s length of FIRs usually are adequate, and yes, I'll be writing the software myself. Right now I'm trying to determine where to apply the processing. Since I want to do both in/out low latency and be able to stream audio (like Spotify), I think ...
by robiwan
Wed Jul 12, 2017 6:29 pm
Forum: Stereo soundcard for the Raspberry Pi
Topic: Lowest possible latency
Replies: 42
Views: 20456

Re: Lowest possible latency

Depends, I'm doing FIR filters in the frequency domain, so it can be 4 instances with lengths of up to 0.5 s (24000 taps @48K). I'm planning on a partitioned implementation to remove the latency due to FFTs. Maybe dual-rate to lower the lengths of the IRs. I'll see how it goes. Also, it is possible ...
by robiwan
Wed Jul 12, 2017 5:02 pm
Forum: Stereo soundcard for the Raspberry Pi
Topic: Lowest possible latency
Replies: 42
Views: 20456

Re: Lowest possible latency

Ok, I've setup my Pi with the stereo board (and have been streaming Spotify via Mopidy, sounds really good! :) ) Anyway, built the ALSA latency test and got following results: ./latency -r 96000 -f S32_LE -p Maximum read: 56 frames Maximum read latency: 583.333us, 0.583333ms (1714.2857Hz) Playback t...
by robiwan
Thu Jul 06, 2017 7:35 pm
Forum: Stereo soundcard for the Raspberry Pi
Topic: Lowest possible latency
Replies: 42
Views: 20456

Re: Lowest possible latency

Thanks! Will do so.
by robiwan
Thu Jul 06, 2017 4:40 pm
Forum: Stereo soundcard for the Raspberry Pi
Topic: Lowest possible latency
Replies: 42
Views: 20456

Re: Lowest possible latency

To clarify, I'm seeking to minimize the latency of the audiopath:

ADC -> ALSA -> DAC

:)
by robiwan
Thu Jul 06, 2017 12:56 am
Forum: Stereo soundcard for the Raspberry Pi
Topic: Lowest possible latency
Replies: 42
Views: 20456

Lowest possible latency

I've tried finding the latency of the WM8731 codec, but there's no specific information on this in the datasheet. I suspect it to be low though, on the order of < 0.5 ms. I've bought the soundcard in order to make a system with as low a latency as can be achieved. I suspect a 32 sample ALSA period s...
by robiwan
Wed Jul 05, 2017 5:49 pm
Forum: Stereo soundcard for the Raspberry Pi
Topic: Chipset
Replies: 2
Views: 1673

Re: Chipset

Nevermind, I saw that the Wolfson WM8731 is used. Seems like a very good codec.
by robiwan
Wed Jul 05, 2017 7:19 am
Forum: Stereo soundcard for the Raspberry Pi
Topic: Chipset
Replies: 2
Views: 1673

Chipset

It's said that the AD/DA supports 96 kHz 32 bits, what chipset is used for this ?