[LAU] Komplete Audio 6 and Jack (solved with alsamixer switches)

[Len Ovens]

On Wed, 13 Aug 2014, David wrote:

> Thanks everyone. I've typed out everything I went through in case someone 
> else stumbles on this with a similar problem

No problem. I learn too.
>> On Tue, 12 Aug 2014, David wrote:
>>> Rode condensor mics.
>> Does the KA6 have phantom power turned on (48v switch on the back)?
>
> The Rode website says that this mic doesn't care either way about phantom 
> power, but in any case I've tried it both on and off. Apparently some mics 
> can be cooked with phantom power!

Generally a condensor mic needs power, either batteries, phantom or a 
power supply of it's own. Ribbon mics are known to be sensitive if the 
cable happens to be miswired.

> In the Audio tab of QJackCtl Connections window, under "system" I get 6 in 
> and 6 out, so I guess that's it.

Right, two mics(1,2), two lines(3,4) and two from s/pdif(5,6). The outputs 
are similar. Perfect.

> I had never heard of meterbridge. I did <$ jack_lsp> and it gave me 
> "system:capture_1" etc etc, but when I started meterbridge I got no signal,

Ya meter bridge is kind of funny, the *.desktop file starts it with two 
meters that are supposed to be connected to alsa_pcm:playback_1 and 2 so 
on my system that means they are not connected to anything. But it is a 
handy signal indicator for trouble shooting when not using it for 
metering.

> Alsamixer proved interesting. I've never used it before. First I had to

It is something to remember as it deals only with the sound card where 
many other mixers deal with psuedo/soft controls.

> select the KA6 using <F6: Select Sound Card> and then I'm presented with an 
> arcane screen. I messed around by tabbing through "monitor control front" 
> "monitor control rear" and "monitor control 1" and typing <m> at each 
> position. That changed the "MM" (mute?) in the box above each item to "00".

Yes M is mute. I have gotten sound out of things using alsamix when 
nothing else works. It shows up interdependancies rather well too. (where 
moving one control affects another - I have one where muting one channel 
mutes three and unmuting only unmutes one)

> This seemed to create some sort of magic because now I'm getting a vu-meter 
> reading on <$ meterbridge system:capture_1>. I can't understand why altering 
> the monitoring should make the input work, but apparently it does. Pressing

Probably routing would be a better word than monitoring.

> <F4> in alsamixer tells me that "this device does not have any capture 
> controls". Very odd.

Quite common actually. You control the level with the physical controls on 
the box... although it seems with this one the volumes that look like 
output may affect the input. The manual was not that clear to me.

>> One wonders which volume control pannel that is, and where within that.
>
> I'm talking about the system settings volume control widget that lives on the 
> taskbar.

Ah, pavucontrol then, controls PA. Fine for desktop stuff like browsing 
though.

> After discovering alsamixer mute switches (thanks!), if I go to
> volume control -> sound setting -> input device
> the item labelled "Built-in Audio Analogue Stereo" is now responding - ie: 
> the level meter moves when I test the mic. I can change the mic level there.

I think it may be a soft level if alsamixer doesn't show it.

> It's a bit obscure and doesn't refer to the KA6 at all - but hey, if it works 
> I'm happy. Does this have something to do with pulseaudio-module-jack being 
> installed??

No, just pulse itself.

> exactly what I needed. Audacity now records sound from the KA6 with a mic 
> plugged in. Next to try some actual recordings!
>
> Where do I send the pizza?

It is just nice to see someone else enjoy linux audio and not go away 
frustrated.


--
Len Ovens
www.ovenwerks.net