TASCAM M-312B Calibration Question...

[Ignatius-]

Hey guys...

I have had this m-312b for a little more than a week and have been having a little trouble with getting the levels set properly. I was calibrating it with the free version of True RTA last night (1kHz test tone [at -10db] from my computer to a channel via 1/8'' -> 1/4" cable), and the levels seemed unusually low. I kept the channel fader in the shaded area (like the manual said - in between 7 and 8) - my computer was at max volume - but I had to crank the line TRIM almost to the max to get the level to 0 on all four channels. And the PGM faders were all up around 9. This seems off (?).

Also, there is pretty harsh crackling whenever I move any of the faders (channel/PGM/stereo master). And when I move a PGM fader the level on whatever respective VU meter jumps all over the place before it settles on a level - it is not a nice, smooth ascent or descent. The stereo master faders, however, do have a smooth ascent/descent when they are moved.

I feel like I am doing something wrong, but I can't figure out what it is. I have been reading through the manual for the past week, and I feel like I might be using the monitor function(s) incorrectly... but I don't know. Should the test tone be at 0db instead of -10db (since it is going into the 1/4" input)? Should I just try and clean out the faders (like sweetbeats' video explains) - could it be signal interference from dirty faders?

Any help would be appreciated...

 

[The Ghost of FM]

Your faders do sound noisy and in need of cleaning, so yes, follow the advice that sweatbeats has layed out. Or, prior to doing that, rapidly move the faders back and forth several times to see if you can get the faders to self clean by being exercised a bit, which in many cases can clean up the issue you described. If that doesn't work, then follow sweatbeat's cleaning advice.

About the level issue. I wouldn't bother trying to calibrate the mixer to a tone generator program from your computer unless all of your signals that you're going to be put through the mixer are also originating from your computer which is obviously not outputting a standard -10db line level signal that the mixer's line inputs are looking for. Ordinarily, when a normal sound source like a keyboard or drum machine is plugged into those inputs, you should be able to have the trim control at somewhere abound the 1 o'clock position on that knob and achieve a 0 VU meter reading with the channel and PGM fader in the shaded area of the fader.

What is your recording regime, equipment wise? Are you tracking to a reel to reel analog deck or are you just using the mixer as a front end to a computer based recording system? And what instruments and microphones will you be using with the mixer?

Cheers!

 

[Ignatius-]

I wouldn't bother trying to calibrate the mixer to a tone generator program from your computer unless all of your signals that you're going to be put through the mixer are also originating from your computer which is obviously not outputting a standard -10db line level signal that the mixer's line inputs are looking for.

That makes sense... the only thing is that I was calibrating an M-216 using the same program - and the same method - and I really didn't have any problems with it being too quiet. However, I could have been pumping the gain somehow and not known it. I am relatively new to analog recording (a little more than a year) and have absolutely no experience with the digital world of recording - except for some extremely frustrating attempts with some free software. ... which is one of the reasons I was asking about this method of calibration.

I am tracking to a Tascam 34b and [once I get tape, which is on the way] mixing down/"mastering" to a 32. I mostly do electronic-type stuff - hardware samplers, synths, and amps (for the keyboards and guitars), but I also [have] record[ed] piano, drums, brass and woodwind insturments (when I borrow some decent microphones)... kind of a mix of everything. I haven't tried using the XLR/MIC inputs yet because they look pretty rough. I will have to take a weekend and clean this board up a little bit!

Any idea about the PGM faders and the funky readings on the VU meters? I have to say it was kind of concerning... could that have been from the gain being boosted a lot? It just seemed like they were ultra-sensitive... I would simply put my finger on the fader and the meter would move. Not to mention when I actually moved it... any ideas?

Thanks for the reply!

 

[The Ghost of FM]

About the program faders acting jumpy with the level, again, this is a sign that they're dirty and need to be cleaned.

About the odd low levels even with the trim control all the way up, ensure that the PAD button is not depressed as this will reduce the incoming signal strength by 20 or 30 db. If it isn't pressed in and on, I would try the test again with a different device such as one of your keyboards which has a standard line output.

The problem with the computer method is that the program on screen can tell you anything it wants to with respect to level strength but if your sound card is not up to standard levels, via its on screen mixer controls, it doesn't actually mean anything.

Also, you said that you tried this method with a different mixer previously. Was this also with the same computer and sound card, with the computer's mixer levels at the exact same settings? I assume something is not consistent with that.

Cheers!

 

[Ignatius-]

Yeah... the computer setup was exactly the same when I was calibrating the other mixer, and the 30db pad was not on. Also, I tried out some of my keyboards and the levels were still low - but still only on the channel/PGM faders. When I engage to yellow L/R button the stereo faders seem to be showing the proper VU measurement, and the monitor section (with the tape returns) is also monitoring normally. So I'm just thinking that I really need to clean these faders up.

I didn't notice it at first, but it seems like the guy I bought it from sprayed/wiped it down with something before he gave it to me to "clean" it... so maybe whatever that substance was got into the faders. I don't know. I guess I will have to see when I get it open.