Recording to PC: low mic level

[Joel Glassman]

Hi everyone--
I've got a frustrating but probably basic problem! Signal path:
AKG condenser mic to Mackie 1202--from 1202 MAIN-OUT to LINE-IN on Soundblaster Live Platinum card to Cakewalk Pro Audio 9. [Windows mixer app seems to be set correctly and the signal out of the Mackie to a PA is fine.] When I record an audio track the software console VU gets up to only -48db. The recording is at a very low level & somewhat distorted. I'm stumped. Should I be sending a mic level signal from the 1202 to the soundcard's mic input? [how?] Hopefully its not necessary to buy another mic preamp instead! Any thoughts you have would be gratefully appreciated. --Joel

 

[DonF]

What kind of cable are you using to connect the Mackie to the SoundBlaster? If you're doing this wrong, you might be getting a phase cancellation effect, which might explain the extremely low levels you're seeing.

You don't need another preamp (not for the sake of getting a hotter level, anyway!), and you absolutely do not want to plug anything into the sound card's microphone input.

 

[Joel Glassman]

Hi Don,
I'm using a standard instrument 1/4" plug to mini plug cable.
thanks--Joel

 

[DonF]

I think that's your problem, then. What you need is a "Y" cable such as is used to connect a portable CD player to a receiver. It has two RCA plugs on one end (one each for L and R), and a 1/8" stereo plug on the other end. If the Mackie doesn't have RCA outputs, you'll need a couple of 1/4" to RCA adapters.

 

[Chibi Nappa]

The Mackie should be able to give plenty of signal from its 1/4 inch outputs. I don't think that is the problem...

 

[DonF]

Yes, the Mackie is capable of providing an adequate signal level. But you won't get squat on the other end if you don't use the right cable.

 

[Chibi Nappa]

I'm not quite following here.... A cable is just a wire. Different ends on that wire shouldn't change the sound properties at all.

Look on the Mackie and see if there is a +4/-10 switch anywhere. Maybe that is in the wrong position....

 

[DonF]

Chibi,

In general, the ends would not have too great an effect. But there is one common exception: if you connect a balanced differential output to a stereo input using a TRS patch cable, you wind up with identical, but phase-reversed, signals appearing at the L and R inputs. If these are then combined, Poof! the signal disappears.

Since the Mackie's outputs are balanced, but not differential, that is clearly not what's going on here.

I suspect that Joel is using a TS-to-mini, single-conductor patch cable. This should give him a signal on one input channel at the SBLive. I can't remember off the top of my head which channel that would be, but if the software uses the other channel as its mono input, he's hosed. At any rate, using the right connectors can never be a bad thing.

BTW most (all?) Mackie boards have fixed outputs at 0dBu.

 

[bgavin]

Consumer sound cards are -10dBV (0.316 volts rms). If the Mackie is a pro-audio level of +4 dBu (1.23 volts rms), there is a voltage mismatch.

There is also an impedance issue between the two.

If you use the RCA connectors on TAPE OUT, that should be an impedance and voltage match for your sound card. Both are referenced to -10dBV.

 

[DonF]

Both the 1/4" and RCA outs on the 1202 are at the same nominal level, 0dBu (not +4!). At any rate, this would not explain the low-level/distortion problem that Joel described. A wrong cable, on the other hand, might lead to these problems, since you could be driving the wrong output channel like mad, and hearing only the low-level, horribly distorted crosstalk coming from the other output channel. (I'd think that you'd see some red lights flashing in this case, though.)

In general, a low-impedance output will have no trouble driving a high-impedance input, so I doubt that impedance is an issue here.

I can't wait to find out what the problem actually is/was! Joel?