Topic: Split Omnis - Reducing Extra Bass in Post vs. Avoiding It All Together

[cottle]

I ran split omnis the other night at Isbell/Mule, and the tapes (Mule moreso than Isbell) have a little too much bass.  Everything else sounds clear, but when the bass drum hits, it rumbles pretty good. 

Can someone tell me:
A) how to avoid this from the get-go (i.e. should I have used bass rolloff  or something?)
and
B) can this be dealt with in post?  I've examined some threads, and I've tried playing with a high-pass filter or compression, but neither seems to make much difference in the end result. (I'm using Audacity)

Nothing sounds muddy until the bass drum hits, and when it does, ONLY the bass drum sound muddy.  It doesn't wash out the highs or mids.  I'm at work now, but I'll edit this post later this afternoon and add a sample track of the raw audio from each set for an example.

If responding with advice, please dumb it down...I'm a noob.

Thanks!

[Scooter123]

You have the right idea on the high pass filter.  I typically make a couple passes at it, starting at 40htz, then 50htz, then 60htz if necessary.  I might even go up to 70htz.  After that, I'd start fiddling around with EQ. 

My bet is the typical bass drum is around 80-90Htz in a large room. 

[taperj]

you also have the right idea with the rolloff, I run a Sound Devices Mixpre so this is based on that device. It has 2 rolloffs, I usually use the 80Hz rolloff @ 6dB per octave which has a nice natural effect in heavy bass situations. I would use things like this discriminatingly though, in the wrong situation these rolloffs can contribute to making your recording too thin.

[boojum]

My experience is to fix it in post.  You can undo the damage there if you take out too much.  Take out too much while recording and it is just too bad.     

[cottle]

If I were to use a rolloff while recording, would it be better to set the rolloff on the mics (AKG 460) which have an option of 75Hz or 150Hz, or to use the low-cut filter on my recorder (PMD-661)?

Thanks.

[momule]

IMO.  your always better off using the low cut filter/rolloff on the input source (mic in this case) I agree with some posts that state you can roll it off in post using software but I find it not truly the same.

[easy jim]

^ I usually find that I would set the roll off setting in post at a different point, and maybe also with a different slope, than the mics' setting(s).  I think using the roll off settings on the mics is more applicable to live mixing and/or sound reinforcement, and we should take advantage of the greater precision possible via post-processing.

[datmike]

I use large diaphragm mics (Microtech Gefell UM70S) so I have to be very careful using them in boomy rooms, etc.  I've ruined many-a-recording with blown out base over the last 20 years and I've tried just about every combination of setting for different situations. 

I'd say, in general, it is better to roll the bass off at the source and/or while recording, rather than during post processing.  Blown out bass bleeds over many lower frequencies and distortion (thud, thud, thud) is hard to hide...plus the higher frequencies are not going to be recorded using a lot of available headroom, making you compensate for it in post.

It sounds a lot cleaner, imo, to kick the bass up a little, rather than roll-off post-recording.

Here is a little sample of 2 recent shows I recorded at a local venue.  The first is Steve Kimock Crazy Engine recorded with bass roll-off at 80Hz.  This recording kicks ass. 
http://www.archive.org/details/skce2009-04-02.aud_albright

The second is Strings For Industry (Scott law with Bill Nershi).  A quieter ensemble in the same location but some weeks later. Same setup, different sound guy and no bass roll-off.  The kick drum is a little blown on this one, partly due to the sound guy....but anyway...I should have rolled off on this one!
http://www.archive.org/details/pt2009-05-04.aud_gefell_albright

[cottle]

Thanks guys.  I was able to clean up the recordings a little in post.  There's still some remnants of the distorted low-end, but not too bad compared to the original recording.

[easy jim]

...Blown out bass bleeds over many lower frequencies and distortion (thud, thud, thud) is hard to hide...plus the higher frequencies are not going to be recorded using a lot of available headroom, making you compensate for it in post...

I think that statement - especially with respect to using up headroom - is not so true if capturing in 24 vs. 16 bit resolution, and harmonic distortion from sloppy lower frequencies not affected by a roll off filter (in capture or in post) will still be there.

It sounds a lot cleaner, imo, to kick the bass up a little, rather than roll-off post-recording.

If you have a way of doing it that works for you, that's cool.  It's results that matter.  But, in my experience, subtractive EQ (low end roll off, and notch filtering in general) pretty much always sounds cleaner to my ears and seems to translate better across multiple playback systems.

[guysonic]

I don't feel there should be a difference in sound quality from mic rolloff setting from doing this in post ONLY if two conditions are met when doing the original recording.

1) Mics used have adequate loudness handling of at least 130 dB SPL for moderately loud pop/rock, and more loudness handling for loud and very loud bass venues for getting clean signal into the recorder. 

2) Recorder input (either MIC or LINE) can handle peak mic output signals.

As most of you already know, the 1st stage of the recorder (mostly talking mic input, but on some decks also line) can get clipped distortions but show good VU while producing a 'muddy' bass result. 

So if the mic can handle the loudness, and the deck is marginal, engage the mic's pad, or insert a 10-15 dB in-series one between the mic and the deck's input.  I think if these conditions are met, and taking advantage of 24bit depth, post bass reduction should sound as-good-as-it-gets and has advantage of tailering the bass to exact taste.