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anonymous 27 August 2008

Hey everyone - first time poster here!

So, the short story is that my new job wants me to trouble shoot a problem with their voice over studio. I have some experience as I have a very nice home studio and record a lot, but I am not a pro, and don't know all that much about voice over work.

Here goes:

We are using a Shure SM7B / MBox / SoundBooth setup and there is a problem with low level distortion. I know the SM7B is a great choice for voice over (industry standard), however, being a dynamic mic it's output is low. I am guessing that the pres on the MBoxes have some inherent distortion, and the volume difference between the signal level to the distortion level just isn't big enough to mask it. The distortion is through out the entire track, and doesn't appear to be related to digital overs (as far as I can tell), and I can hear it, albeit faintly, on the latency free monitoring on the MBox which means it's happening before the signal gets to the PC. It's not too loud... until the necessary compression goes on the track, and then it's problematic.

I have tested the mic at home (works fine) and swapped cables (no improvement). I just think the Mboxes aren't up to this particular task. I am think we either need to a) run a separate higher gain pre before the Mbox and defeat the Mbox's pre (if even possible) or b) get a better interface with louder / cleaner pres. Or c) get a high gain pre and a new interface with defeatable pres. I am leaning toward the second option, but am not sure what interface would work best. I'd like to keep the mic (it's a very noisy room) if possible. I sure could use some advice from people who have worked with this mic before as to what to get. Oh, and I'd like to keep USB *if possible*, so as not to have IT freak when I ask them to install a card.

Any advice would certainly be appreciated!

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Comments

anonymous Wed, 08/27/2008 - 14:00

You mean noise, not distortion right? A hum or static that is not dependent on how loud the person talks?

It could happen if you are running the pre's too low.

When you swapped cables, where they the same make? It could be cheep cables, or perhaps they aren't balanced?

And also I have heard that the pre's in the MBOX 2 aren't as good as it's predecessors.

What MBOX version do you have?
What is the dB level of the noise?
What is the dB level of the voice typically?
What does the noise sound like? Can you post a sample?
On the M-Box is there just one gain adjustment? (I don't know, I don't use one)

anonymous Wed, 08/27/2008 - 14:48

I mean distortion, not noise. Not hum, not static, but buzzing distortion. And it doesn't *seem* to be tied to clipping - it appears in both louder and quieter portions of the recordings, and I see no overs (on the input monitoring in Soundbooth or the Mbox itself). It's the weirdest thing I have ever heard.

To answer questions:

Swapped cables were different makes. One of the cables was Monster, one was Mogami (iirc).

It's the original Mbox.
The noise floor is at about -50db, but the distortion present on the spoken words *sounds* louder than that, but it is hard to tell.
The voice, before gain adjustment or compression, is from -20 to -6ish.
I will post samples tomorrow.
Yes, just one gain adjustment.

I am bringing in a bunch of gear tomorrow (different mic, cables and an outboard pre) to see if I can't get any further on this.

Not to ask a stupid question, but aren't all mic cables balanced?

Thanks!!

anonymous Wed, 08/27/2008 - 15:23

agreatheight wrote: Not to ask a stupid question, but aren't all mic cables balanced?

They should be, but occasionally I find one at a pub, or church that isn't. XLR's on both ends, but only two conductors. Cheaper to make. The cold is floating.

The line that made me think you were talking about noise was:

"the volume difference between the signal level to the distortion level just isn't big enough to mask it."

Does that mean the distortion is apparent? or is there more to it then that?

Sounds is weird. Looking forward to hearing a sample. Sorry I couldn't help.

Good luck,

Steve

anonymous Thu, 08/28/2008 - 09:01

Ug! Still having problems, and running out of time to fix stuff!

Let me ask this - let's say I was to start from scratch (I think it would be quicker than trying to find the problem). For voice over work in a very noisy room, what would you all suggest? I am still leaning toward keeping the mic, but I think everything else may go.

Suggestions?

Codemonkey Thu, 08/28/2008 - 20:56

Example. Now!

"I mean distortion, not noise. Not hum, not static, but buzzing distortion. And it doesn't *seem* to be tied to clipping - it appears in both louder and quieter portions of the recordings,"
So it happens despite the input level. Does it keep happening if you have no input at all (ie not speaking)?

I've heard something like this on an onboard sound card. What I would describe that as, is a buzzing that becomes more apparent with more input signal.
Seem anything like it?

Get a recording starting with nothing being said, then speak quietly, loudly, quietly, leave some more silence, whatever.

Kev Fri, 08/29/2008 - 13:38

can you run a new known mic cable around the hall and go straight to the Mbox.

now do the same but use the external mic-pre

do use both left then right inputs

do you best to think one issue at a time

now the hail marry pass
can you move to another room
either or both
mic room and computer room
get what I mean
( I know that will probably show more about noise induced stuff rather than distortion issues)

but I fear you may have a faulty Mbox and without one handy to swap with, could be difficult to proove

anonymous Wed, 09/10/2008 - 04:59

here's a question. You said that it worked fine when you brought it home.

I'm assuming that you meant the mic.

Have you brought the MBox home and tried it with the mic?

I can't help but to think that the problem is the environment and not necessarily the gear. This would put that argument to rest very quickly.

For what it's worth, that'd be my first piece of advice.

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