Lexicon Alpha - Shure SM58

M

mad_dk

New member
Hi
I am recording using a Lexicon Alpha connected to a Macbook with Logic Pro 9.
I recently bought a Shure SM58 and thought that the preamp of the external sound card would be enough.
However when connecting the mic to the Lexicon Alpha, the signal I get is really low, especially when recording an acoustic guitar, but even for vocals. I tried to turn up the Mic knob on the Alpha but the result just noise with the signal remaining at a very low level.

Will i need further mic preamp like

http://www.thomann.de/index.html?partner_id=97926&page=gb/digidesign_mbox_2_mini.htm

or
ART Tube MP Original Tube Mic Preamp W/ 48V Phantom Power
http://www.dv247.com/studio-equipme...al-tube-mic-preamp-w-48v-phantom-power--20338

cheers
 
The entry-level Lexicon interfaces are notorious for not having the most powerful preamps in the world. You won't get quite as much gain out of them as you can some other brands.

But the best answer is NOT to put a secondr inexpensive preamp in line, IMHO, though that is possible. If you keep the Lexicon, just record at a bit lower of a level, with the gain maybe somewhere around 2/3rds - 3/4ers up at most. Don't boost it higher than that; it might boost the noise level higher than you need to. Then make your adjustments when mixing on your computer.

Remember, you don't want/need to record with your levels peaking up around 0dBFS on your computer; that's an old and untrue wife's tale of digital recording. Recording low is just fine, there's plenty of room on your computer for that without problem. The key is to find the right level in your Alpha where you're getting the most gain from it that you can without pushing it's own noise level up higher than you have to.

G.
 
Note that the lexicon Alpha does not have phantom power, youl need a preamp to supply this :)
The Mbox you linked is an audio interface, and having 1 of those connected to the lexicon alpha would be a little weird. your condensor mic needs phantom power to run, hooking up the preamp that you linked would work. thats the exact combi I run with right now, and it works just fine :)
 
I missed the part where he said he had a condenser mic:confused: the sm58 is dynamic and won't need phantom power though he may want to record with one in the future;)

Wives tale or not, it's nice to start the project with a strong signal...gives you more options down the road. Just don't go into the red with the peaks!
 
Klagen said:
Note that the lexicon Alpha does not have phantom power, youl need a preamp to supply this :)
The Mbox you linked is an audio interface, and having 1 of those connected to the lexicon alpha would be a little weird. your condensor mic needs phantom power to run, hooking up the preamp that you linked would work. thats the exact combi I run with right now, and it works just fine :)
Click to expand...
The only problem with that is that the SM58 is a dynamic mic, and does not require phantom power.

Adding a second preamp in-line would boost the signal, yes, but in this case the phantom power itself is needless. And if the 2nd preamp is any good, he could probably use that alone without the Lexicon and be just fine.

The OP's problem isn't that he needs phantom power or that he needs two preamps, it's simply that the Lexicon preamp is a relatively anemic preamp providing only a spec'd maximum of 50dB of gain. Considering the SM58 has a rated sensitivity of -54dBV/Pa, even at maximum gain, one could probably expect a digital signal out of the Alpha somewhere in the -15 to -20dbFS range (ballpark).

G.
 
Last edited:
i managed to get the knobs on the lexicon fine
and the playback i get is just fine as well
back when actually recording in logic pro the recorded signal is really terrible again.
So i tried recording with the mic in GarageBand and the quality is optimum.
Does anyone have any idea of how the problem in Logic can be fixed?
 
The recording software itself should not make a difference. A few questions and musings:

Just what do you mean by "terrible"? Are you referring strictly to recording level, or is there a problem with the quality of the sound itself, or both?

Are you sure you have everything set properly in Logic, including the levels at all the gain stages on the way in, and in having the proper driver selected and set properly?

Have you gone to the Lexicon web site to make sure that you have the latest and/or best driver updates for your OS version and Logic software version?

G.
 
Yeah it sounds like you still have the inputs on Logic set-up to use the built-in mic on the Macbook.

Logic is really just Garageband on steroids...make sure they both are using the Lexicon as the source in the preferences.

Logic Pro>Preferences>Audio>Devices>Core Audio>[Device=Lexicon Alpha]
 
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