Strong hissing atmospherics when capturing sound

[JowiKrause]

Hi again,
yesterday I got wonderful help to revive my sound cards. Thanks again!
However, I had got them bungled up because I did not get a clear recording from microphone - from the onboard sound card. And when I used the external USB sound card , the recording was clear, no hissing, but very low volume.
The audio hardware is described in this excerpt of my "inxi":
Audio:
Device-1: Intel 6 Series/C200 Series Family High Definition Audio
vendor: ASUSTeK P8H67 driver: snd_hda_intel v: kernel bus ID: 00:1b.0
Device-2: Creative type: USB driver: hid-generic,snd-usb-audio,usbhid
bus ID: 1-1.5.1:4
Sound Server: ALSA v: k4.15.0-45-lowlatency
I am using two microphones, which are obviously not the best, one stands on the table, one is attached to my shirt. No difference in the recording quality.

Now I would need at least one good quality recording device. And I cannot believe, that the on-board sound card absolutely has to record all those atmospherics. It is not crackling, it is simply a rather loud, constant hiss.

What config files could give a hint as to the cause of the problem?

[MrEen]

Hi again, JowiKrause.

For the hissing issue, you probably have too much mic boost happening. In the terminal, type alsamixer and when it opens, press F6 to select the appropriate device. Now look for a column named Mic Boost. Use the left arrow key to select it, then the down arrow key to lower the level.

For the USB device, while still in alsamixer , hit F6 again and check the input levels for the USB device.

Hope those help.

[JowiKrause]

Hi again MrEen!
Thanks for your attention again.
Unfortunately, these hints do not take me far.
I have opened the alasamixer in the terminal, but for the Realtek card there is no MicBoost.
I have uploaded the screenshot here:

When I press F6 to look at the Soundblaster USB, I get this picture:

When I press F4 here for the recoding devices only, I get this picture:

Sorry, all this is in German, but that's how I have set up my computer. Essentially the last message is that this sound appliance has no input control.

And now?
Cheers
Jowi

[MrEen]

From your first image, go back to Alle (F5) and keep hitting the right arrow key. There are probably more options available off screen. Mic Boost is the tenth column for me on the Playback tab (F3) and the thirteenth under Alle.

Still thinking about the USB card.

[JowiKrause]

Ok, did that. Found the Micro Boost (2 channels) on the far right (a place where I hate to go... ) and turned them down completely. Put the Mic to 100%

Result: Yes, the hissing is gone, but so is the microphone, or nearly so. Just now I had the table micro and that recording was very weak. I have to hold the Mic in front of my mouth to get a proper recording.
So probably it really just a bad microphone....
But you got me on the right track now for the Realtek and I can go on experimenting. Thanks a lot!
I will try the other micro later, and hope for some information about the Sundblaster 1240....
Cheers!

[MrEen]

Here's another thing. That onboard sound card has mic ports for front and back. From your last image, you're using the back I assume. Try disabling the front mic (left arrow twice from the presently selected Rear Mic in that image) by using the down arrow on that column. Also, raise the Mic Boost to maybe 50 or so, and lower the mic level to 75 and test it. Might take more experimentation.

Also, that Rear Mic has stereo input set (the 100<>100 under the column.) Use the z key to lower the left side all the way to 0 then test the mic. Use the q key to raise it again if that didn't help, then the c key to lower the right side all the way to 0 and test again. The e key will raise the right side if that didn't help either. That might fix the issue if it's just a mono mic.

[MrEen]

For the Soundblaster, how is the volume level set on the Input Devices tab of pavucontrol? Is it at or near 100%(0dB)?

[JowiKrause]

For the Soundblaster:
I did not get around to replugging it to another port, because I saw your question.
Yes, in pavucontrol I had the input level a100%, and I could barely hear that. Setting it up 150% takes it to a nearly tolerable level,, but I definitely have to shout to make myself heard an recorded.
I also changed between the 2 profiles "Analog Stereo Dupolex" and "Analog Stereo Input" but got no audible changes.

[JowiKrause]

OK, now I'm back after replugging the Soundblaster into a direct USB2 port (no hub)
It took 2x restarting the computer until pavucontrol recognized the USB device again. Second time round it did.
I went to alsamixer and set the input level control at 100% maximum
I went to pavucontrol and set the USB input level to 150% maximum
I did a little recording wit my tabletop microphone - absolutely no changes or improvements.
When I do the recording, I watch the sound level in my Linux Sound Control Center (3rd UI to use) and I can barely see movementin the level bar. Only when I shout or hold it in front of my mouth the level goes up.
The only positive thing about the sound blaster is that there is no hissing.

So in effect both sound devices have the same problem: They need more input. At the level of input they get, they both record a a low sound level. The Realtek can be turned up to record louder, but then the hissing comes back - not as bad as it was before you showed me the Mic Booster control, but still well audible.

Any ideas what else we can try? Or wait until I get a better microphone that provides more input from the start?

Of course some better software to control the sound blaster would be something to try - but from where?

Or maybe I have to try my luck in Windows? The point is: I hate Windows, and I only have one running in a virtual machine. Which will probably cause other problems again....

[MrEen]

As a test, do you have a regular kernel you could try booting into?

I'm afraid sound input is a weak area for me.

Maybe I'll spot something if you run the alsa info script. In the terminal, type cd followed by wget http://www.alsa-project.org/alsa-info.sh -O alsa-info.sh && bash alsa-info.sh then paste the link it will give you. It will take a moment to run.

[JowiKrause]

Hi again,
some time ago I had not seen your response about playing around in the alsamixer, about disabling front mic, and then turning uo and down the mic boost and the mic.
Well, I tried all possible combinations for boost, no boost, little boost, mic up or down, but really get no improvements
Re turning off the front mic, I am not quite shure.
Right now this is what the right part of my a-samixer looks like:

I have some questions:
Why are there 2 capture channels? What do they do actually?
What are the 2 input sources, which you can change for front mic, rear mic and line?
Why do I have 2 rear mic channels, when I only have one rear mic. And when I do any changes, both seem locked together.

Re changing between left and right channels, I have not tried that yet. Where should I try? Mic, mic boost, capture? Or all?

[MrEen]

The changing between channels is on Rear Mic.

This assumes your mic is plugged into the rear (back) of your computer. If it's plugged into the front, we're doing this all wrong.

Where are you plugging the mic in?

[JowiKrause]

OK, I have tried once more with different setting for those channels. I can reduce or strengthen the volume of the recording, but the hissing is always there. Realtek just hisses, that's it.
Re different kernel.... no, I don't have another machine, and I am not sure that I will want to switch to a different kernel.
Actually, I am not sure that I have not switched kernel already without really knowing what I was doing. For some reason, I have a "low latency kernel now, and I am not really sure where it comes from. I think, some days ago there was one of the many steps I took to try and find a driver for that USB device which made me install a kernel which was supposed to include that. But well, you know the results, I am not keen n repeating that.
But I will try to get the ALSA information as you posted. See if something helpful turns up....

[MrEen]

When you installed the low latency kernel, that wouldn't remove the kernel you were using before that.

To get to it, if you have a grub screen when you boot up, you select Advanced Options and I think use the arrow key to select the previous (non low latency) kernel.

If grub doesn't show when you boot up, hold the Shift key down while booting and hopefully it will appear.

[JowiKrause]

Well, I' m afraid that is a lot of information and I have no idea where to look, and for what. I have stored the output of the ASLA info here:
https://drive.google.com/open?id=1FszkH ... 6Ja-ngJwvp
I' m a bit surprised that I have a sound server called jack. Yes, at some point I did install an app that included "jack", but it didn't work and I uninstalled it. Obviously not completely. Synaptic?
And what is this story about the "lowlatency" kernel and the "lowlatency" driver version? Is that something I wanted to know? I' m not sure...
Yes, one thing I do see is that there is supposed to be a module snd_usb_audio, which would be taking care of my Soundblaster., But it doesn' t do a very good job with that!
Wonder if you can get any additional information from all those data? Guess you must know what to look for.
Chers!
Johann

[JowiKrause]

Re front or rear mic.
I only have the sound card and it's connectors in the back panel.
The card would, I presume, support a special front panel, but I haven't got that. So no, I do not think there was a mistake here.

[JowiKrause]

Well ....
I did restart the machine with the former kernel, no "lowlatency", I went into alsamixer, switched to the Soundblaster and turned the microphone up. The picture is this:

And with this setting, the mic volume also at 150% in pavucontrol, with the profile analog stereo duplex, both microphones actually seem to work good enough for me to continue on my project. Although I have ordered a hopefully better one already.
So I will try and rid of that other kernel, do some tidying up tomorrow and take it as it is. Could be better, but I will be able to survive. If need be, I can do some postprocessing to push up the volume of my recordings a little - there is no hissing on the Soundblaster.
And I will dismiss the Realtek as a piece of equipment that I will not use if I can avoid it.
Thank you so much again for all your suggestions - at least my understanding of the different apps I can use to get my sound going has been improved a bit..... and the situation has been improved!
Cheers!
Johann

[MrEen]

Sounds good JowiKrause.

The next time a kernel upgrade comes along, don't be afraid to give the Realtek another try. It may get that card issue free.