Definitions of Retrovol/ALSA terms and relationships?

[vtpup]

I've been trying to get a microphone working with my daughter's computer, and finally succeeded with reference to several threads on the old forum. But trying to tune the settings to get the best sound to noise level, etc. I realize I still suffer from a very old problem: not actually knowing what some of the terms (sliders) in Retrovol mean or do, and how they all interrelate to each other. I wonder if someone more knowledgeable than me either has already defined these in an easy to understand way, or if not whether we can come up with some new clear explanation that would help Puppy users.

Examples I'm still confused about are PCM, Digital, Capture, and how they relate to each other and the other more understandably named controls, like mic, mic boost, internal mic, internal mic boost, Headphone and Master.

Which control affects what kind of input or output device, and which control overrides/affects the other?

Thanks!

[mikewalsh]

@vtpup :-

I get round this in an easy fashion. I use a Logitech USB headset - headphones with a built-in "boom" microphone, that swivels down when I need to use it. This thing has a rather chunky connector.....because it has ts own built-in audio card! And just two sliders to worry about; PCM - this controls the headphone volume, and Capture - this controls the microphone input level. Very simple.....very easy to use. And it works perfectly with Puppy.

You can get standalone USB mics, too, though whether these have their own built-in card, I don't know.

PCM - Think of this as your amplifier's 'Master' output control. The higher it's set, the louder everything will be. Mostly, the advice is to crank this one all the way up, so this then gives you the widest range of adjustment on everything else.

Digital - Don't know about this one. Never had any use for it, but I believe it may be related to hardware with an optical fibre 'digital' audio input? Usually for 'audiophiles' who take their music very seriously, and pay for their equipment accordingly. This one's been showing up more & more in recent years, but you have to realise that some of these chips get used in other equipment besides PCs.

Capture - This one is for setting microphone level when using the standard audio jack sockets, AFAIK.....

As you say, most of the others are fairly self-explanatory, if you stop and think about them. Not every machine gives the same range of sliders, 'cos it's all determined by what controls have been provided by the audio chip's manufacturer.

Others can probably elaborate further, if needs be,

Mike.

[vtpup]

Thanks Mike. The struggle was with trying to get the computer's internal mic going after my daughter's combo mic/headphone mic stopped working. This was for a Zoom class today, so I had to work fast.

Oddly, the retrovol controls "internal mic" and "internal mic boost" were not involved, in fact the internal mic now works with both controls unset and at zero. Go figure.

Anyway back to trying to understand the definitions of the Retrovol controls, I read that PCM means pulse code modulation, and I understand what that means as a waveform and a process, but I still don't know what it means to ALSA and Retrovol. What does a slider for it mean? Especially if there already is a slider for Master?

Well one guess, is that maybe "Master" controls not only a PCM sound source, but maybe also an analog sound source in the computer? That would make sense to me and explain the reason you'd need both.

Okay so we're still left with Digital ... what's that? I mean PCM is "digital" so what is the control "Digital" for?

And "Capture" -- why is that needed for a microphone to work. Especially if there are already controls for microphones, both internal and external. Or is that like "Master" (for outputs), in that it controls several different (input) sources? Maybe that's it..........

Oh, also, what does loopback do? Sorry to ask what may seem like basics to others.....

ps. well, a bit of humor, even the home website for ALSA has its confusions.......a sine wave shown in the PCM explanation is referred to as an ordinary sinus wave..... No, it's snot.

[vtpup]

Okay, new discovery:

1.) None of the microphone controls work with either of my two laptops' internal microphones: Mic, Mic Boost, Internal Mic, Internal Mic Boost -- all 4 have no effect. You can turn them off and the microphone still works because:

2.) The internal mic is controlled by both Digital, and Capture. And both of those are linked. If you enable one, you enable both. And both sliders affect the microphone volume independently.

The above was tested on two different laptops (listed in my sig), one running Tahrpup 6.05 and one running Bionic64.

BTW, here's a quick and easy way to test your microphones (internal or external) and Retrovol controls:

1.) Open Retroval
2.) Open MHWaveEdit
3.) In MHWE click on Play>Record
4.) A VU meter monitor panel will open up and you can test your mics and settings. Tap or speak into the mic, and try out different settings.

[mikewalsh]

Here I have two mics.....BOTH 'external'. (Well, when did you last hear of a desktop with a built-in mike..?? )

Either the Logitech headset (has its own card, can be selected from the MultipleSoundCard Wizard), or

The Logitech c920 HD 'Pro' webcam (has stereo mikes, but these can only be selected by entering 'alsamixer' in the terminal, then selecting them from there. Probably it's not seen as a separate card - even though it is - because it's record-only; no 'playback' controls.)

I've customized things a wee bit. I have an icon in the notification area which, when I click on it, brings up a YAD-powered GUI that lets me select which mic I want to use, AND whether or not to set it as default.

Mike.

[vtpup]

That's interesting Mike. I still would like to know if people with laptops or chromebooks are having similar results with either the built-in microphone, or with plug-in mics when using Retrovol. Are they finding that the only controls for those are Capture/Digital, or do they find that the Mic/Internal Mic/Boost controls have any effect? I've actually seen the latter interfere with microphone operation.

Because I have two different laptops with two different puppy generations on them, and yet these controls act the same weird way, I'm wondering if this is a universal trait of Retroval on Puppy. And if it is, this fact might clear up some frequent confusions in getting microphones to work. I mean if all controls labeled "mic" don't work for a user, the computer or operating system will take the blame. But the solution is actually a simple, if paradoxical, one.....turn those microphone controls off and drop their sliders to zero! Bump up Capture/Digital, and the microphone should work.....

[greengeek]

Sometimes the mic volume controls only alter the 'feedback' into the play circuitry. In other words if those controls are maxxed out you should hear your own spoken voice looping into the headphones. This function can be useful for PA uses (if you have a big amp and also feedback control)

Often the only available mic volume adjustment for recording is the capture slider combined with 'source' selection, and sometimes there may also be a 'mic boost' or '20db' tickbox.