7

I'm running Debian (10.5) with the 5.7.0 kernel and Gnome. I've previously asked this question here, without luck: http://forums.debian.net/viewtopic.php?f=7&t=147161

Here's the situation: I have a Samson XDP2 wireless Lavalier microphone (http://www.samsontech.com/samson/products/wireless-systems/xpd-series/xpd2lav/). It consists of a transmitter pack, to which a lavalier microphone is connected, and a USB receiver, which also has a headset output.

If I listen in on the receiver using the headset port the sound is fine -- strong and clear.

However, the sound that I receive in linux is very, very weak.

By default Pulseaudio allows you to boost via GUI to 153% (norm*2). Using pactl set-source-volume in the terminal I can boost the input enough that I get a good signal (ca 270% -- no clipping, and the dynamic range sounds fine to me).

I will have to go in and do this manually each time, and if I touch the slider in pavucontrol or gnome-settings then I lose the boost.

My questions are:

Can I set the default boost permanently (to 270%) for this device via a pulseaudio configuration file, so that it applies every time I plug in the device?

AND/OR

Can I change the allowable volume range in the GUI (pavucontrol or gnome-settings) so that I can use the slider up to e.g. 300%?

What I've done: I've fiddled with the pulseaudio source code -- I changed volume.h from PA_VOLUME_UI_MAX (pa_sw_volume_from_dB(+11.0)) to PA_VOLUME_UI_MAX (pa_sw_volume_from_dB(+35.0))

but it changed nothing. I've also changed org/gnome/desktop/sound/allow-volume-above-100-percent to true via dconf. The sliders are limited to 153%. I've even done the window-y thing and rebooted for the first time in months.

So what can I do to make a solution as hands-off as possible? I use the mic for lectures and there are enough distractions (students asking questions, cleaning up after the previous lecturer, setting up cameras and computer) before a lecture that it's easy to forget to adjust the input volume.

Cheers in advance.

1
  • 1
    I have the same issue just now I was trying to solve it and this was one of the first search hit. I did not tested yet and I'm not sure I will be able to do today, but is seems that "set-source-volume" can be used also in /etc/pulse/default.pa. So something like: set-source-volume 1 300000 could work. Since I did not tested yet I don't know if it works and you can still use volume slider without losing the volume.
    – tuxfan77
    Sep 9, 2020 at 20:37

1 Answer 1

5

I'm an Arch user but the issue you have faced is common to any distribution and seems to occur depending on the hardware support and driver's side.

There are workarounds and maybe with time it will be fixed by someone skilled enough to code a few lines.

There are two approaches to this case, one easy and one less so:

1. Via app (the easy one)

The 150% of override incoming volume is not enough for many. For what I discovered there is no boost in neither pavucontrol, alsamixer, nor ecc that can do the job of raising the mic rec sound level to decent numbers.

But you can use PulseEffects!

PulseEffects screenshot 1

PulseEffects screenshot 1

It's a very good equalizer that allows to control the boost channel for input and output. If you are a PulseAudio user you have to install PulseEffect-Legacy-git that still uses the PulseAudio core.

The last version of this equalizer use PipeWire and you should substitute PulseAudio with PipeWire to make it work.

In the program:

  • icon top left playback and microphone (each for the sum gain)
  • Limiter setting (enable the checkbox left of the "Limiter" label)
  • move the input to 36db. Then you can fine the right combo between the PulseAudio override and the equalizer. I'm using it on an Asus Xonar AE with a cheap mic and the result is very good, no rustling at all.

2. The coder approach

ALSA offers the "softvol" solution. This one should be the cleaner solution. I would like to apply it but I'd need to learn too many new things, that takes time.

https://alsa.opensrc.org/How_to_use_softvol_to_control_the_master_volume

In ~/.asoundrc or in /etc/asound.conf we can make the modifications. aplay -L will show us the devices to use and redirect.

See the link for the rest.

We can create a redirect control that applies the gain we want to the input source (personal "db" range). So with just a permanent control we can use the mic as we want. This guy made something similar for the SPi:

https://raspberrypi.stackexchange.com/questions/89966/how-do-i-increase-the-input-volume-of-a-microphone-connected-to-pi-its-using-th

This second solution could be integrated into ALSA libraries to make it useful for other distros.

1

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .