Topic: Newb question about mic distortion

[scottspur]

Hey, I recently got a marantz pmd670 digital recorder that I've been using to record some classical recitals for a college, and it has been working great for that.  However, I wanted to use it to record some of my bands performances too, but have had serious problems with the recordings coming out distorted to the point where they are unusable.  I am using a pair of oktava 012s with the -10 pad straight into the marantz pres.  Looking at the levels in ProTools on the waveform I've recorded, everything looks fine, but every time there is a deep bass note or if I'm in a club that's really pumping the kick through the subs, everything distorts.  Is this the mic diaphragm distorting?  Could the vibrations in the room be overloading the circuitry somewhere?  It seems like a lot of people are using this mic to record rock shows so I'm kind of stumped.  Any idea what's causing the distortion?  Thanks!

Scott
www.hotspurmusic.com

[scottspur]

That was my first instinct too, but like I said, everything looks kosher in ProTools when I drop the WAV file in.  None of the waveforms look like they've been flattened out, the WAV peaks around -10, and the meters on my recorder looked ok with no clipping.  I found some specs on the mics that say they are good for 125db from 250hz on up.. thats pretty irrellevant imho, since the high SPL stuff is going to be below 250hz, right?  Is it still possible that this is a preamp issue?

Line in isn't really a great option since that means external phantom power or external pres..I'd prefer to avoid that.

Scott

[bluegrass_brad]

Your brickwalling the pre's in the Marantz. It wont show any clipping, cause thats not what is happening.  It's just overloading the pre's.

[ethan]

Your brickwalling the pre's in the Marantz. It wont show any clipping, cause thats not what is happening.  It's just overloading the pre's.

You should still be able to see brickwalling if you zoom in and look at the peaks.

So what is the playback device here? Not headphones right? Some distortion can be a playback system not being able to duplicate the wavform.

=e

[ethan]

None of the waveforms look like they've been flattened out, the WAV peaks around -10, and the meters on my recorder looked ok with no clipping. 

Ding! ok this is classic brickwalling

[bluegrass_brad]

None of the waveforms look like they've been flattened out, the WAV peaks around -10, and the meters on my recorder looked ok with no clipping.

Ding! ok this is classic brickwalling

[scottspur]

Playback device is a PT LE rig, I do studio work on it all the time.  I can rule that out pretty definitively.

Is everyone thoroughly convinced that I was overloading the pres?  I had some gain dialed in but I guess what you're saying is that the input circutry (before gain) was being overloaded?  Can anyone recommend a solution?  I could do external pres into the line in, but what a pain.

Scott

[Javier Cinakowski]

Oade does the basic mod on any Marantz, regardless of where it was purchased.  I am not sure if that mod would increase the mic-pre headroom.  It is certainly worth emailing Oade imo....

[ethan]

Playback device is a PT LE rig, I do studio work on it all the time.  I can rule that out pretty definitively.

Is everyone thoroughly convinced that I was overloading the pres?  I had some gain dialed in but I guess what you're saying is that the input circutry (before gain) was being overloaded?  Can anyone recommend a solution?  I could do external pres into the line in, but what a pain.

Scott

Put a preamp infront of your marantz and go line in, you could buy line tranformers and put them infront of your marantz and go line in or you could try as others have suggest and go directly line in. How are you powering your mics? with the marantz? if so than the last option is probably not an option without using a power supply like the PS-2.

[scottspur]

I'm powering the mics with the phantom from the marantz, so line-in isn't a great option.  Plus they're phono plugs.  I'd prefer not to use external preamps if at all avoidable.  Maybe an inline pad?  Anyone had any experience with that?

I've been doing live and studio audio for about 5 years now and I've never heard of a mic overloading the input circuitry on a preamp before the gain stage...nuts!

Scott

[BobW]

Try applying an HPF from 150hz @ 6db / octave on a short sample that has the distortion  in your editor and play it back
Brickwalling should splatter across the spectrum, if I understand it correctly
That would mean that it has affected the upper registers on the recording, as well as the low
Hence, if the HPF causes the problem to disappear, I'd be less inclined to think it that

Post what happens, if you can