recording woes

I recently got myself an M-Audio FireWire Solo and an average quality ribbon microphone. Got the RTkernel+JACK+Ardour combination to run without too much trouble (using Fedora 12). I have used JACK previously, years ago, but Ardour never before. All and all, I’m not very experienced with this kind of stuff (Linux yes, sound engineering no).

Now, when recording, I only get very low volume in Ardour, even if the M-Audio Solo indicator says the signal should be clipping. I can turn the M-Audio gain all the way up and scream at the mic, and it still gives only like -20dB in Ardour.

If I keep the M-Audio input gain low, I get a clean recording, but it’s way too quiet. If I turn the gain up too much, the recording becomes distorted (as if it actually did clip seriously on the way) but the volume is still pretty low (like it was lowered after the clipping).

I can’t trace where this clipping takes place. The M-Audio clipping indicator is not blinking, and the volume levels in Ardour are way too low to clip, so that leaves (as far as I can tell) JACK or my output(?).

Also, I tried to export one recording into a wav-file to listen to it through my onboard soundcard and some other software (just to see if the sound data has distortion, or just the playback from Ardour to my M-Audio), but the export resulted in an empty file (just silence). Probably did something wrong there…

I realise that the above doesn’t give too much information. Ask if you need to know more. What I’m hoping to hear are some educated guesses as to what might cause my problem.

P.S. I also could not run jackdmp even though I have a dual-core processor. Any ideas as to why this is? It didn’t give any special error message, just the usual “failed to start Jack, sorry”.

I am still puzzled about the distortion, as there should not be any digital clipping unless Ardour indicates it. So to me it seems more likely that the distortion happens inside the M-Audio, but the interface gives only the described weak signal through Jack to Ardour. However this appears really unlikely to me. I suppose you use the ffado driver? Have you had a look at the ffado-mixer? I don’t know the device, but there might be some interesting settings to check out there.
However, I think I can help you with your exporting problem. In the export dialog, you have to decide which channels’ output you want to export into the file. In your case you probably have to check the top-left (master: out-1 left) and bottom right (master: out-2 right) box.

Hope I can help. Just ask if something is unclear.

Actually I was not using ffado but its predecessor freebob. And qjackctl doesn’t list ‘ffado’ as a possible driver but instead ‘firewire’ which I suppose refers to ffado.

Anyhow, I switched the setting from ‘freebob’ to ‘firewire’, and after JACK restart the whole interface works. Now I don’t get the odd distortion anymore, so it was probably caused by freebob somehow. BUT: the volume is still too low.

ffado-mixer doesn’t let me do anything useful. It just shows me “FW Solo (Dummy)”, and “Nickname: unsupported”, and an otherwise empty panel with the text “this panel is merely a placeholder for devices that don’t have a mixer panel yet”. I can change the sample rate and the clock source, but that’s it. Does this perhaps mean that the FW Solo isn’t fully supported by ffado? From the stdout output of ffado I gathered that the device was correctly identified. And well, it works, so there has to be some support.

The distortion being away lets me record at least tolerably audible sounds, so I can live with the current situation. I read somewhere that I could plug the M-Audio device to a Win/Mac machine and set the levels there, but for obvious reasons I’m reluctant to resort to that.

Oh, and thanks for the info on exporting! I had missed the check-boxes.

Volume being too low might simply be related to the fact that ribbon mics, historically, have very low output, and require mis preamps with quite a bit of gain.

What ribbon mic do you have?

Ricardus is right with the fact that ribbon mics have very low output due to the fact that there is only a tiny peace of aluminum moving inside the magnet. However, you have mentioned before that the M-Audio indicates clipping when you yell at the microphone (you must have a pretty loud voice being able to get that much output out of a ribbon mic!), but Ardour still shows low levels.
I have checked on the ffado website and found that the Firewire Solo is only “Reported to work” not “Fully Supported”. So it seems likely that the interface works fine, but there is no mixer panel for all the internal routing and stuff.
I have also had a look at the manual of the interface and read that the internal mixer allows attenuation of the input signal. I am afraid you have no other choice but hooking your M-Audio up to a PC running Windows, installing the mixer software there and setting the inputs to no attenuation. That way you would only control the input levels with the hardware gain poti.