Here’s what I’m trying to do - simply overdub some acoustic guitar onto a pre-recorded mp3 file that I imported. I’ve started Audacity, imported the mp3 and connected my guitar to an MAudio MobilePre, and plugged that into the USB of my Linux box. I have a decent input level set that barely clips into the red and my volume on my acoustic up at 10. I hit Shift-R to record a new track. I have my headphones plugged into the MAudio’s headphone jack. I hear audio from the imported mp3 but I don’t hear anything from the new track while I’m playing thus I can’t record in time. After I stop recording I can playback and I hear both tracks now. My new track is extremely low even though I have the recording level maxed and the level on the MAudio at a decent level.
It’s hard to read some of the things in Audacity since my monitor’s a UDH and I’ve scaled up the text so I can read things and Audacity doesn’t properly render the Audio Host, Recording Device, etc. properly
Yeah, and? You do realize that I’m having a problem hearing my guitar when I am recording right? I can hear stuff when I simply play it back but when I am recording my guitar I can’t hear anything thus I’m flying blind. Also, I can hear the original, imported mp3 track, even when recording. Just not my guitar. That’s the problem!
Here’s what my volume control looks like:
Note that in my example there’s the Starship/Matisse HD Audio Controller Analog Stereo button there which is my sound card on my Linux box and it’s there because there’s another sound card in my HDMI monitor. Also, when I plug the MAudio in that appears too. I can route the audio of the playback to any of those cards. Again, that’s not the problem. The problem is when I’m recording I can’t hear what I’m playing.
Also, note that in the other tabs there are also settings for these soundcards like Recording, Output Devices, etc. I’ve played with each of them trying to get my guitar to make a noise when recording to no avail which is why I’m here asking questions.
To monitor what you are recording while playing, without too much delay, you need to either use hardware that provides zero latency monitoring (you plug your headphones into the recording device), or you will need to use Jack Audio System.
For zero latency (hardware) monitoring, Audacity is irrelevant. I’ve not found any documentation for how to enable hardware monitoring on Linux. M-Audio just say that it is “software controlled”, which I assume means with their (Windows / Mac) control panel app. If you don’t remember how you got it working last time, then perhaps worth asking on https://linuxmusicians.com/ if anyone there uses the MobilePre.
Regardless of zero latency or non-zero latency - why can’t I hear what I’m playing when recording?
I’m only using this MAudio thing because the other guitarist in the band had one. I could invest in something better but I don’t know which I should invest in. If there is no way to enable hardware monitoring on Linux then what’s the point of buying any hardware interface? I also don’t understand what you mean by “M-Audio just say that it is ‘software controlled’”? Isn’t it hardware to start with? Isn’t it an “USB Audio interface” thing? And yet it’s software controlled? Is it somehow not software controlled on Windows/Mac but only software controlled on Linux? Or do Linux drivers lack whatever Windows/Mac drivers have in order for it to perform well?
And why did it work before? Are you saying that in the old system the soundcard (or whatever) was able to control the MAudio so as to make it zero latency? Because I did this before and was able to to record my guitar through it on the old machine, hear it while recording and play in time.
kozikowski, how is my MAudio different from this Behringer thing?
From M-Audio’s website, the MobilePre routes the input signal to the headphone socket when enabled by the M-Audio software, but the official M-Audio software appears to only be available for Windows and Mac. If you had this working previously on Linux, then there must be some way to enable monitoring on Linux, though I have not found any information of how to do that.
The other option is to use “software playthrough”, which is when the input is routed to the output through the computer. The problem with this method is the time it takes for the sound signal to make the round trip (“round trip latency”). To enable software playthrough:
“Transport menu > Transport Options > Software Playthrough”.
The delay is typically around half a second unless you use low latency drivers such as ASIO (Windows) or Jack (Linux).
That’s the million dollar question - what did you do before that is different from this time?
If I remembered exactly what I did before I wouldn’t be here.
I’m not attached to the MobilePre - I’ve only borrowed it. I’m willing to purchase a better one… if it works. As you mention many (most? all?) manufacturers of these units support only Windows and Macs so I don’t want to go out and spend money on some other unit only to find it also doesn’t work.
WRT Software Playthrough, IIRC it either made it so I couldn’t hear anything or when I used it before on the previous system, made it such that the latency was intolerable.
WRT to Jack all I can say is that I don’t know jack about Jack, 'cept it’s yet another way on Linux to handle sound. I think I played with it long, long ago when I was also having problems with pulseaudio and decided to stay with pulseaudio. Jack seemed picky and buggy. Now I’m thinking Jack may be the way to go as you mention it is lower latency. Question: Should I switch my audio usage entirely over to using Jack or only when I want to record stuff? Is it easy to say set up a script to say something like “setsound jack” and “setsound pulse” so I can “toggle” on Jack for recording and toggle back to pulse for normal usage? Can Jack and Pulseaudio be used simultaneously?
Any device that uses standard USB audio should work on Linux. As far as I’m aware, all of the 2 channel Behringer devices work on Linux (I use a UCA-202 which is just a 2 in/out line level interface). There are many other makes / models that work on Linux. The thing to be wary of is anything that requires special drivers or software.
The M-Audio MobilePre USB is standard USB audio compliant except for the monitor level, which is software controlled.
I would recommend asking on Linux audio forums to see what others are using and any issues they have.
Jack is good these days, but it can still be a pain to get it set up. Unless you really need to use Jack, it’s probably not worth the time and effort (if you really do need it, then it’s absolutely worth the time and effort).
As for “any device that uses standard USB audio should work on Linux” as you say M-Audio MobilePre is standard USB 'cept monitor level which I find odd. Secondly, I don’t know how to ascertain that say the Behringer device is standard USB audio compliant including monitor level and M-Audio MobilePre is standard USB audio compliant except for monitor level. How do you determine this?
I’ve see a few reviews of that Behringer and they mentioned it’s a $30 device but I find it on Amazon for $96. I find it at Sweetwater.com for $48 but nowhere for $30. Odd.
Yes that is peculiar. I guess they were saving a couple of cents by not having a physical switch. The Behringer UMC202HD has a push button switch to enable direct monitoring.
For some reason that we are not aware of, the UCA202, UFO202 and UCA222 have recently rocketed in price in the US, They are still available in Europe for well under $30, so perhaps it has something to do with the current US/China trade relations (I believe they are manufactured in China for a German company).