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Gear / Technical Help => Post-Processing, Computer / Streaming / Internet Devices & Related Activity => Topic started by: Mr.Scully on November 22, 2011, 09:45:53 AM

Title: Bass drum distortion due to bad placement of mics
Post by: Mr.Scully on November 22, 2011, 09:45:53 AM
I know the usual distortion caused by clipping at too loud gigs cannot be repaired in any way. But my recording was volume-wise okay, I just had my omnis (SP-CMC-8 + battery box) almost at a waist level in quite a bad sounding venue so I got this distortion on bass drum and possibly also on bass guitar. Would anybody be so kind to check the four samples and let me know if there's anything that could be done with that? (I use Goldwave). I tried to lower the bass level but it doesn't help much (and being an amateur, I usually use only preset options when using sound editors). Don't know if any noise reduction filters would help...

http://www.QueenConcerts.com/tmp/rammstein01.flac
http://www.QueenConcerts.com/tmp/rammstein02.flac
http://www.QueenConcerts.com/tmp/rammstein03.flac
http://www.QueenConcerts.com/tmp/rammstein04.flac

(Normally I wouldn't care but I'd like to use a good sounding audio for a video of this concert and I haven't come across any other source yet (Rammstein live in Prague - November 12, 2011).

Thanks
Title: Re: Bass drum distortion due to bad placement of mics
Post by: Mr.Scully on November 30, 2011, 03:57:27 PM
Nothing at all? Is anybody at least able to tell me if remastering is possible in this case or if I should give up?
Title: Re: Bass drum distortion due to bad placement of mics
Post by: Gutbucket on November 30, 2011, 04:14:50 PM
I haven't listened but noise reduction will not help.  Some DAW software and plugins have a 'clipping repair' algorithm which attempts to re-draw the clipped peaks on the waveforms.  I've not used that myself, but something like it may or may not help- it's worth a try but probably no silver bullet. 

More of a hail-marry pass would be to run a highpass filter in an attempt to eliminate the distorted bass frequencies, the result will sound quite thin and you will probably still hear distortion in the higher frequencies and bass harmonics.  If the mid and highs sound OK after filtering, you could try a bass synthesis type plugin which attempts to re-create missing fundamentals below still-existing, higher bass harmonics.  If that all sounds Greek to you, it's probably not worth putting the effort into as it is likely to not work very well anyway.
Title: Re: Bass drum distortion due to bad placement of mics
Post by: Mr.Scully on December 01, 2011, 02:23:39 PM
There doesn't seem to be any clipping, the waveforms look okay but the distortion is still there.

I played with the sample a bit today. The right channel seems to have slightly less bass (and distortion) than the left channel so I can spread the right channel over both channels and then run a highpass set around 120 Hz which seems to give a compromise - half of the distortion is gone and yet it doesn't sound THAT bad without all those missing bass frequencies.

I've always thought bass distortion appeared when the volume was too loud and the waveforms were clipped, the peaks were gone. But in this case the waveforms look okay and yet there's a lot of distortion. From now on I'll be using only cardioids, they always sound good.
Title: Re: Bass drum distortion due to bad placement of mics
Post by: newplanet7 on December 01, 2011, 02:33:53 PM
Distortion and levels a lot of time don't coincide. When that happens
I'm in the camp about placement, either location, or configuration is the culprit.
Because you had them at waist level is why you got the distortion.
Also, the omnis should have been fine in this situation with a direct or semi-direct line to the source.
Cards would've fared just as bad IMO.

Have you tried rolling off starting at 80Hz? 
Title: Re: Bass drum distortion due to bad placement of mics
Post by: Gutbucket on December 01, 2011, 03:33:54 PM
From now on I'll be using only cardioids, they always sound good.

Really? That's a pretty broad brush. Cardioids are generally less sensitive to the lowest freqencies than omnis, which can compensate for less than ideal bass-heavy mic placements or PA mixes. But that doesn't necessarily mean the problem is the low frequency sensitivity of omnis, or omnis verses cardioids in general.

Cards would've fared just as bad IMO.

Title: Re: Bass drum distortion due to bad placement of mics
Post by: Mr.Scully on December 01, 2011, 04:08:03 PM
Well I have used cardioids about 30 times in various venues without a single problem. Used omnis twice and got distortion twice (once without battery box, I admit). Maybe I should have set the bass roll off to 80 Hz as suggested.
Title: Re: Bass drum distortion due to bad placement of mics
Post by: Gutbucket on December 01, 2011, 04:21:41 PM
It could either be the mics themselves distorting (which would be a problem of that particular omni, not all omnis as a class of mics), for which bass rolloff on the battery box or recorder won't help, or it could be the recorder input stage distorting, which could be helped either with bass rolloff or by attenuating the signal before the recorder or possibly recording at a lower level.

If the cards you have work and give you good results use them instead.  I'm just trying to clarify some aspects of your problem while pointing out that the issue you are having isn't a problem of omnis in the general sense, but something specific to your particular setup, situation or settings.
Title: Re: Bass drum distortion due to bad placement of mics
Post by: newplanet7 on December 01, 2011, 09:03:35 PM
But my recording was volume-wise okay, I just had my omnis (SP-CMC-8 + battery box) almost at a waist level in quite a bad sounding venue so I got this distortion on bass drum and possibly also on bass guitar.
Unless you were running onstage on a stand, I'd say the waist level of the omnis was the culprit.

Edit to add, I've had the bass drum overload once with cardioids running open when
levels looked normal. I chalk it up to placement and configuration.
I rolled off @80hz and ran a HPF with salvageable results.

Title: Re: Bass drum distortion due to bad placement of mics
Post by: TimeBandit on December 02, 2011, 09:36:51 AM
Maybe test an new battery on the bbox or at least another battery box from which you know it works.+

Your mics got lowsens / 4k7 mod?



Title: Re: Bass drum distortion due to bad placement of mics
Post by: Mr.Scully on December 02, 2011, 10:13:22 AM
Maybe test an new battery on the bbox or at least another battery box from which you know it works.+

Your mics got lowsens / 4k7 mod?

No idea, to be honest. I think I bought them here in the yard section. I know the SP-CMC-8 omnis without the mod can handle about 125 dB but it's very well possible some rock gigs are even louder.

I ordered the CA-14 omnis from Chris together with his ugly battery box. Is that with the lowsens mod or would I have to buy the preamp as well? I like my SP-CMC-8 cardiods but I'm not quite happy about the bass so I've always wanted to give a chance to the omnis but with no luck so far...
Title: Re: Bass drum distortion due to bad placement of mics
Post by: F.O.Bean on December 11, 2011, 04:39:33 AM
Maybe test an new battery on the bbox or at least another battery box from which you know it works.+

Your mics got lowsens / 4k7 mod?

No idea, to be honest. I think I bought them here in the yard section. I know the SP-CMC-8 omnis without the mod can handle about 125 dB but it's very well possible some rock gigs are even louder.

I ordered the CA-14 omnis from Chris together with his ugly battery box. Is that with the lowsens mod or would I have to buy the preamp as well? I like my SP-CMC-8 cardiods but I'm not quite happy about the bass so I've always wanted to give a chance to the omnis but with no luck so far...

What I would do, is sell the SP mics and get the CA14[cards AND omnis], and you'll be covered for any situation. Besides, isnt Chris from Church Audio STILL running a killer deal for both CA14s+Battery Box/9100 ??? I just sold my CA14[card/omni] setup into an SP Battery Box and a CA 9100, and after listening and doing an A/B test w/ my big boy mics, ala Schoeps mk41>KCY>Sonosax, and I really was/am BLOWN AWAY, that you can get such a KILLER SOUND, with a pair of mics I scored for less than $100.00 smackaroos :) I already posted to the LMA, the mk41/sonosax source from Papadosio on 11/25, and now that I have a lil free time, I will post the CA-14[Cards]>CA 9100 source so you can see how well they performed :) I certainly dont hear a 4k-5k difference in sound, thats for sure. I'm kinda kicking myself in the arse for selling my CA14[cards/omnis], an SP Battery Box, and a CA 9100. I can def see myself buying them back rather soon, just as long as I get my Busman Actives first :)
Title: Re: Bass drum distortion due to bad placement of mics
Post by: Mr.Scully on December 12, 2011, 07:20:21 AM
Yes, I have took advantage of the November sale and ordered the CA-14 (omnis + cardioids + ugly BB) so I'm curious what they sound like. Haven't received any email from Chris since my paypal payment (not even any order confirmation) but he has a good reputation so I'll just wait and see :-)

In the meantime I used my SP-CMC-8 cardioids in a London club (approx. 2000 people) and got a very nice result. But each microphone in this price range is a compromise. My "old" Sony ECM-719 offers a nice "full" sound but with too much audience noise. This SP-CMC-8 gives a great clean sound but somehow lacks "power" and "drive". I'm really curious where these CA-14s stand.
Title: Re: Bass drum distortion due to bad placement of mics
Post by: TimeBandit on December 12, 2011, 09:10:45 AM
Yes, I have took advantage of the November sale and ordered the CA-14 (omnis + cardioids + ugly BB) so I'm curious what they sound like. Haven't received any email from Chris since my paypal payment (not even any order confirmation) but he has a good reputation so I'll just wait and see :-)

You should contact Chris again he posted he had some computer issues and lost some emails, just for being sure your order has arrived.