Recent content by phofman

Is it actually possible? https://github.com/mikebrady/shairport-sync?tab=readme-ov-file#latency-stuffing-timing :

I agree, IMO the same effect is here - 120R of the mux vs. the 10k of the other resistor, times the mux THD => 0.2% THD * 0.01 ratio => some 0.002%, rough calculation. Absolutely inaudible. Yet IMO worse than performance of a good DAC chip. IIRC Ivan talked about using FETs as input attenuator...

I am afraid I do not understand. If a wire (zero resistance) has 0V potential against some common ground, such information does not say anything about a current running through that wire. A neutral wire from a 240V 2kW heater has zero voltage (against ground, you can touch it :) ) all the time...

Hm, please correct me if I am wrong. The analog mux is part of a voltage divider between outputs of U3A and U7A where U7A tries to keep its inverting input at virtual GND (i.e. equal to its noninverting input). To get 0V at the inv. input, a current must flow through the voltage divider, i.e...

@Frunse: Do you have any data to support those circuits would be better than the digital VC in your DAC chips? CD4051 analog switch has THD of 0.15% - 0.3% - check the datasheet. No noise figure, but I kind of do not think your circuit with so many resistors and opamps in the signal path will...

Very nice. Just a note - since the newer kernel has async UAC2 gadget, the CDSP config should enable rate adjust. CDSP will hit (sooner or later) xruns without that. If the gadget were adaptive (as in older android kernels), it would require rate adjust and async resampler.

Does your RPi airplay receiver or your airplay source have volume control? Maybe your RPi3 analog output is too weak for your amp. Easy to check e.g. with speaker-test -t sine - for details https://linux.die.net/man/1/speaker-test

You can try hw devices - hw:CARD=Headphones, DEV=0 for playback and hw:CARD=Loopback,DEV=0 or 1 for capture, depending what device you use on the other side https://henquist.github.io/0.6.2/backend_alsa.html#alsa-loopback

Fix that russian if you want my help, please.

I wonder what the default:CARD=XXX actually does. IMO it's mixing dsnoop on capture and dmix on playback + plug. IMO it should be changed to hw:CARD=XXX, or optionally plughw:CARD=XXX. Rate adjust - Loopback runs at RPi clock. The "headphones" PWM device integrated in the GPU part is most...

So do I. RK3308 is designed specifically for audio and its feature set is quite unique. But Pi S does not expose all the handy capabilities of the SoC. The low consumption which allows to power the SoC from standard USB port even when running at full 4 cores @1.3GHz is very handy too. I am...

@godmax: Making any non-RPi ARM board work properly with any reasonably new kernel is ALWAYS a major fight. Most of SoC manufacturers care about android kernel only, android is their market. Very few customers actually request/run non-android linux on non-RPi SoCs. If you are not deeper into...

That's correct behavior - the gadget alsa device provides data only when the USB host plays some audio. If not, the device is stalled. CDSP handles the stall gracefully. Or you can start CDSP with projects like https://github.com/pavhofman/gaudio_ctl or...

Robert, I am not comparing digital vs. analog volume control, but digital in the player/DSP vs. digital in the DAC. Volume control in vast majority of DACs is digital too. If your tweeters hiss at zero volume, simply your analog chain (including the DAC) is electrically too noisy. Of course...

I am afraid the latter is the case - if you arduously calculate an operation at gazilion precision and then throw away most of the precision (explicit truncation to 32 bits samples, implicit truncation to 22bit noise/signal resolution), the resultant number will be identical to making the...