Taperssection.com

Gear / Technical Help => Battery Boxes, Preamps, Mixers, ADCs, and Processors => Topic started by: hardrain62 on July 20, 2011, 01:48:44 PM

Title: Holy bass distortion ... will a bass roll-off pre-amp fix this?
Post by: hardrain62 on July 20, 2011, 01:48:44 PM
Hey gang,

So it's been a long time since I've stealth-taped ever since buying my first open taping rig a few years back, but being that we're in festival season, and many festivals don't allow open taping, I pulled out my Sound Pros croakie mounts which suited me well many years ago. So I'm taping at BOMB Fest in Hartford, and my rig is Sound Pros SP-BMC-12 Binaural Mics (in croakies) > Sound Professionals SP-SPSB-10 Battery Module > Sony PCM-M10 (Mic Sens. Low @ 16-bit). I love the croakie mounts for festivals because you can pretty much wear them all day and it's not really a hassle for you, and the mics inside my croakies I found have always been crisp and reliable. But taping at BOMB Fest yielded less than desirable results. At the main stage, the bass was so intense, I swear my eyeballs were vibrating. I've never once had a problem with bass on a recording though, so I thought nothing of it, and came home to find that a day's worth of recording had very noticeable bass distortion. I'm off to another festival this weekend, and cannot go through the emotional distress of coming home and reviewing a day's worth of taping to find similar results, haha. So! What are my options? Do I just need to order the SPSB-11 w/ bass roll-off mod? I was also reading on this forum that recording in 24-bit (which the M10 is capable of) can alleviate the need for bass roll-off? Would be very curious in exploring that option as well. As it is the free option.  ;D

Any advice would be greatly appreciated! I've attached two samples below for you all to review, so you can see what kind of distortion I'm talking about. (The band is Best Coast)

http://www.mediafire.com/?mdubu2ja7ob7rry

http://www.mediafire.com/?bsayi5aasse57pa

-David
Title: Re: Holy bass distortion ... will a bass roll-off pre-amp fix this?
Post by: jlykos on July 20, 2011, 02:02:59 PM
Without listening to the samples, my guess is that the mic capsules were overloading and could not handle the bass put out at the concert if the volume was as loud as you say it was.  In that instance, a bass rolloff filter will not work because the distortion from the capsules would not be affected by the rolloff applied at the recorder.  The only way around this, IMHO, is to purchase new microphones that are not as sensitive.  If you record concerts that have that level of consistent SPL levels, you may want to check out the dpa 4061 microphones or something like that.
Title: Re: Holy bass distortion ... will a bass roll-off pre-amp fix this?
Post by: hardrain62 on July 21, 2011, 08:09:08 PM
Thanks for your input! I also spoke with Chris from Sound Pros and he basically said the same thing. It makes sense to me, but I guess I never really stopped to think about exceeding max sound levels, because I've never once experienced the problem. But I just ordered a set of AT943's (CMC-8) w/ low sensitivity mod. for overnight delivery. I can't wait 8)
Title: Re: Holy bass distortion ... will a bass roll-off pre-amp fix this?
Post by: TimeBandit on July 22, 2011, 10:05:46 AM
record in 24 bit, brings really a bit more headroom.
but if it´s really the case the mics overloaded, 24 bit can do nothing when the signal is already damaged on it´s way to the recorder.

how old was the battery on your BBOx which you used on the festival? if too old maybe not strong enough anymore to feed the mics.

Title: Re: Holy bass distortion ... will a bass roll-off pre-amp fix this?
Post by: F.O.Bean on July 22, 2011, 08:07:41 PM
I would run 24bit and record rather low to medium levels(-20>-12db), then you simply add the rest of the gain or normalize in post ;)
Title: Re: Holy bass distortion ... will a bass roll-off pre-amp fix this?
Post by: Gutbucket on July 22, 2011, 10:18:13 PM
I would run 24bit and record rather low to medium levels(-20>-12db), then you simply add the rest of the gain or normalize in post ;)

Yep, the additional headroom available with 24bit is entirely from running lower levels.  If you peak just as high as recording to 16 bit there is no additional headroom.. only more foot room that is probably nothing but a bunch of useless noise.