Microphone pre-amp?

Hi everyone !

Been lurking now & then… :slight_smile: I’m currently using a big PC setup under Linux with an external USB card with microphone pre-amplifier to record my singing (have fun with looping & overlapping tracks), guitar and play synthesizers / piano through USB-MIDI.

Wondering if the current Zynthian hardware specs would allow me to do the same ? I’m really looking forward to a way of not having a full computer constantly turned on (cannot focus !).

Do I still need an external microphone pre-amplifier ? Can I get rid of my Focusrite Scarlett 3G ?

Is the jack delay better with the RPi 4 ? (with my current PC I can get as low as 0,666 ms of audio delay ! for simple stuff of course).

Best regards & thanks again to everyone involved !!!
Sorry for all those questions :wink:

Yes … and no! I mean, you can do synthesis, recording, processing and looping with zynthian, but probably you use different tools for doing that with your PC … different tools, different interface, different hardware … i think there are too many differences for doing the same :wink:

The HifiBerry DAC+ADC, the current official soundcard, has a preamp that can be configured by jumper like that:

  • Balanced Input, Gain +12 db
  • Unbalanced Input
    • Gain 0 db
    • Gain +12 db
    • Gain +32 db

You can check the full specs here:

https://www.hifiberry.com/docs/data-sheets/datasheet-dac-adc/

Please, read the specs and the documentation, and search the forum…

Regarding the latency, you should know that in digital audio processing:

lower latency = lower audio-processing performance

You can adjust the latency to the value you want, but the lower the latency, the lower the audio processing power you can use before having XRUNs. So, you shouldn’t use a lower latency than you can perceive (and you can be sure: nobody in the earth can perceive a latency of 0.666 ms, my friend!)

Have you calculated the time that sound take to travel from your monitor-speakers to your ears?
Let’s suppose a short distance of 1.5 m between your ears and the speakers …

t = 1.5m / 350m/s = 4.3 ms

Regards,

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Hi ! Thanks for your reply and sorry for the newbie questions.

I actually checked for terms like “microphone” and “pre-amp” on the forum to no avail. Sorry !

Regarding the latency / xruns, I ask this because it really seems to also depend on the hardware (not only in terms of raw cpu power).

For instance, on my Linux PC, when using the integrated DAC (which is quite good actually), I get tons of xruns unless I set a delay of approximately 40 ms while I can reach less than 1 ms with the USB soundcard on the same machine for simple tasks. Of course 1 ms is ridiculously low, that was just a test :slight_smile: ; but with 40 ms I could hear a very disturbing echo when monitoring the microphone for instance :slight_smile:

Thank you again so much for all you’ve been doing in the past few years !!

Audio input is quite recent. For sure we need more info about it … jeje! But we have some entries:

Regarding the latency, zynthian “hardware” latency is quite low when using I2S, although i can’t give you a number. Anyway, is low enough so you don’t need to worry about it. Normally, in zynthian, “software” latency is bigger than hardware one, and software latency can be adjusted via jackd parameters. By default it’s configured to 5.8 ms but it can be changed easily …

Regards,

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@jofemodo : that sounds absolutely perfect for my use case. v3 kit ordered :slight_smile:
Thanks again so much !

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