Taperssection.com

Gear / Technical Help => Ask The Tapers => Topic started by: T.J. on March 25, 2008, 10:59:08 PM

Title: Reducing Bass in Post
Post by: T.J. on March 25, 2008, 10:59:08 PM
I know there is a couple threads already about this, but I have a specific recording I would like to reduce the bass. I read those threads and didn't really get a clear answer to my question.

here is a short 24/48 sample:

http://www.mediafire.com/?jxrx49mnrca (http://www.mediafire.com/?jxrx49mnrca)

I want to do this using a minimalist approach. I don't really want to get into any sort of EQ. All I want to do is roll-off the bass a little. I have Wavelab at my disposal. The problem I have is that there seems to be a lot of options and I'm unfamiliar because of inexperience. So I'm looking for advice.

Somewhere on this board I saw mention of going Process>Dynamics>Presets>Hard and Soft Limiters. I don't know the difference. Plus I'm not sure how to actually apply them. Am I on the right track or should I be looking elsewhere?

After I trim the bass a little I would just add some gain and be good from there hopefully. So essentially I guess I'm looking for the quick fix  ;D

Thanks In Advance!
Title: Re: Reducing Bass in Post
Post by: KLowe on March 26, 2008, 08:02:59 AM
do a spectral analysis and see where the big bump is in the bass world.
go into EQ and "flatten out the bump" to taste.....
or...just run a high pass filter and set it to 120Hz.....
Title: Re: Reducing Bass in Post
Post by: T.J. on March 26, 2008, 08:44:30 AM
thanks kevin +T

where is the HPF in wavelab? is it a plug-in?
Title: Re: Reducing Bass in Post
Post by: easy jim on March 26, 2008, 12:58:03 PM
or...just run a high pass filter and set it to 120Hz.....

^ That may be a bit heavy handed.  I rarely set a high pass filter any higher than 80Hz.  If the frequencies above that are too strong/resonant, a notch filter is probably best to flatten the bump (or even possibly a shelf filter if all frequencies below or above __ frequency are too strong).  With a high pass filter, it is good in my experience to start at around 40hz and slowly move it up the frequency band until 'it sounds right.'  'Mud' usually resides in the region of ~ 40-80Hz.  If your ParaEQ allows for controlling the slope of the high pass filter, you can also try changing the filter rate and make the curve steeper (seems -12dB/octave is the common 'default' rate, though -6/-18/-24/-30/-36dB/octave filter settings are also available on a lot of the 'better' ParaEQ plug-ins).

Like KLowe suggested, spectral analysis is your friend.  I would not try any limiting or compression if this is just a 2 track aud and your primary goal is to trim the low end.
Title: Re: Reducing Bass in Post
Post by: aegert on March 26, 2008, 02:26:08 PM
Here is a picture of a good eq with the roll off set to 50hz -12db/octave  I circled the spot in red that that change was made with:
(http://www.motb.org/rolloff.JPG)
Title: Re: Reducing Bass in Post
Post by: Dede2002 on March 26, 2008, 04:30:57 PM
do a spectral analysis and see where the big bump is in the bass world.
go into EQ and "flatten out the bump" to taste.....
or...just run a high pass filter and set it to 120Hz.....

A little bit off topic. Does Audacity has the Spectral Analysis feature? Maybe with some other name.
Thanks in advance ;)
Title: Re: Reducing Bass in Post
Post by: KLowe on March 26, 2008, 05:32:26 PM
do a spectral analysis and see where the big bump is in the bass world.
go into EQ and "flatten out the bump" to taste.....
or...just run a high pass filter and set it to 120Hz.....

A little bit off topic. Does Audacity has the Spectral Analysis feature? Maybe with some other name.
Thanks in advance ;)

I KNOW Cool Edit Pro has spectral analysis (audacity is CEP right?)...anyways.  I've used it and it is very pretty.

Title: Re: Reducing Bass in Post
Post by: intpseeker on March 26, 2008, 08:00:35 PM
I am doing some post work in Audacity that is really bass-heavy. I selected the entire set and opened the GLAME Butterworth ( ?) Highpass and ended up with this cutoff frequency (hz) setting: 341.700012 with a resonance of 0.755000.

It did what I wanted and the recording sounds really good, but I don't have a freaking clue what the settings are.

Folks have talked about cutting out anything below 40, so any idea what these settings mean?
Title: Re: Reducing Bass in Post
Post by: Sunday Driver on March 26, 2008, 08:45:44 PM
do a spectral analysis and see where the big bump is in the bass world.
go into EQ and "flatten out the bump" to taste.....
or...just run a high pass filter and set it to 120Hz.....

A little bit off topic. Does Audacity has the Spectral Analysis feature? Maybe with some other name.
Thanks in advance ;)

I KNOW Cool Edit Pro has spectral analysis (audacity is CEP right?)...anyways.  I've used it and it is very pretty.



Audacity is freeware. Adobe Audition is the continuation of Cool Edit Pro.
Title: Re: Reducing Bass in Post
Post by: T.J. on March 26, 2008, 09:22:45 PM
Did I ever say how much I love this freakin' site?  ;D

Okay, I think I have a better understanding about how this all works. I've never really used a spectral analysis, but after analyzing a couple sections where there is heavy bass it appears my "spikes" occur b/w 40-60Hz. So I set the Q equalizer in Wavelab to 50Hz and -12dB (please check out the attached image to let me know if I did have the settings right). That sounded pretty good because it cut the bass causing the muddy sound, I think  :P I tried a couple other settings (50Hz and -6dB / 60Hz and -12dB / 120Hz and -12dB). They all yielded different results. Since my "spikes" were occurring around 50Hz, I think I'm going to stick with that.

My questions are:

-For people who use Wavelab: Am I doing this correctly?
-Is 50Hz and -12dB considered a "modest rolloff"?
-I think I understand what I'm looking for in the Hz "spikes" on the spectral analysis. How can I determine what kind of db slope to use by looking at the spectral analysis?
-I guess this is technically considered applying EQ?

Thanks for all the advise so far. +T's.
It's just another case of trial and error with no right or wrong answer....just like everything else involved in this hobby  ;D
Title: Re: Reducing Bass in Post
Post by: KLowe on March 26, 2008, 09:28:49 PM
yes....that is considered EQ.  ;D....and I REALLY hope you learn that EQ is not a bad word.  If faced with the choice of listening to "mud" b/c that is was the room sounded like or listening to an EQ'd tape that is balanced....then your damn right I'm gonna EQ (everytime).

also....I don't consider -12db to kill mud that bad.  I usually chop off anything below 40hz on principal.  Then I adjust the "mud" to what my ears like.  It may only be -3db or -20....but I generally play around with bumps in the mid/highs and cuts in the lows.  I screw around with it until it sounds "right" (whatever that may be to you).

I release tapes into the free world.  If people like em...then hells yeah.  If they don't....then I'll gladly hook em up with the masters and they can do what they please.

most imp...have fun with it.

KLowe
Title: Re: Reducing Bass in Post
Post by: RobertNC on March 26, 2008, 10:15:06 PM
Going forward, I suggest you give the on-board low cut filter of the 722 at least a try for any kind of amplified recording. 

At first I was really reluctant to try it it myself.  One because I kind of agree with Moke on the -12dB slope seeming a little steep.  Two because I also labored under the concept of you can always take away later.

But once I got over my initial trepidation and decided to try it at a show, I was really pleased with the results.  The 722 gives you a mixed analog/digital filter.   I run  it at the minimum setting -12dB/40Hz.  The first -6dB at 40 Hz is in the pre-amp stage, all the rest is in digital.  But wow!  That first analog pole really seems to put the 722 in a sweet spot.

For the stuff I tape - Dead Family and electric bluegrass mostly - I feel like the onboard filter really cleans up my recordings without stepping on the low end at all.  I have not recorded a show without the low cut filter since I started using it.

Give it a try some time.
Title: Re: Reducing Bass in Post
Post by: BayTaynt3d on March 26, 2008, 11:58:35 PM
Why do it during recording when you've got much more control in post?

Isn't the only reason to do this related to if you're overloading? If you're not overloading, why not wait?
Title: Re: Reducing Bass in Post
Post by: RobertNC on March 27, 2008, 10:18:56 AM
I don't know enough about how pre-amps, capacitor coupled filters, etc work to be able to give any kind of scientific explanation.

But for the kind of music I record, to my ears, I think the low cut filter on the 722 sounds better than the same amount of low cut done in post.
Title: Re: Reducing Bass in Post
Post by: T.J. on March 27, 2008, 10:30:17 AM
Thanks for the opinions Robert. It has crossed my mind to use the on board low cut on the 722. I agree that you can lock into the 722's "sweet spot" when using it as an all-in-one box. Case in point would be running my levels peaking around -7 to -9dB at 24bit (I guess this goes without saying with other recorders doing 24 bit too). I am hesitant to try it because I am affraid my recording *may* not have enught bass bump when all's said and done.  

Do you think band or venue ultimately influence your decision to run the low cut filter? I have a couple specific bands and venues where I think it could be beneficial, just trying to gauge your opinion.

Title: Re: Reducing Bass in Post
Post by: Dede2002 on March 27, 2008, 11:08:10 AM
Thanks for the opinions Robert. It has crossed my mind to use the on board low cut on the 722. I agree that you can lock into the 722's "sweet spot" when using it as an all-in-one box. Case in point would be running my levels peaking around -7 to -9dB at 24bit (I guess this goes without saying with other recorders doing 24 bit too). I am hesitant to try it because I am affraid my recording *may* not have enught bass bump when all's said and done.  

Do you think band or venue ultimately influence your decision to run the low cut filter? I have a couple specific bands and venues where I think it could be beneficial, just trying to gauge your opinion.



My humble 2 cents here. Yes, band and venue should be considered in your roll-off decision. I've had my share of bad experiences leaving all the bass work for post. But never had a bad experience running bass roll-off in really bass heavy shows. In such concerts ( really heavy) the bass will be preserved. But a much more controled bass.
Again, I'm not a scientist. This is just my experience. ;)
Title: Re: Reducing Bass in Post
Post by: RobertNC on March 27, 2008, 11:11:36 AM
Outdoors so far is the only place I've really considered not runnning the low cut since I started using it, and that has only been two shows.  One was Ratdog and one was Phil Lesh.  

I was thinking about not running it for the Bob show, but ended up not making the decision one way or another.  My partner decided she wanted to go to the show, something I generally don't encourage, lol, and argghh, of course I was waiting on her at the bathroom when the show started.  Luckily I was taping with another guy and he started my deck rolling, and the low cut was enabled in my default config, so I just ran with it.   I don't think it hurt to have it on at all.

Phil even outdoors definitely benefitted from a little low cut.

Pretty much everything else I have taped since I started using it has been either pretty loud, in a boomy room or both.
Title: Re: Reducing Bass in Post
Post by: easy jim on March 27, 2008, 12:32:55 PM
My questions are:

-For people who use Wavelab: Am I doing this correctly?
-Is 50Hz and -12dB considered a "modest rolloff"?
-I think I understand what I'm looking for in the Hz "spikes" on the spectral analysis. How can I determine what kind of db slope to use by looking at the spectral analysis?
-I guess this is technically considered applying EQ?

-If you're happy with the results, T.J., I think that is what's most important.  To try and aswer your questions, I do not use/know Wavelab but the image/settings look correct to me for applying a -12dB/octave hpf @ 50Hz.

-I'd consider a -12dB/octave hpf @ 50Hz relatively "modest," especially since most standard speakers/playback systems do not respond well below 60Hz anyways.  What matters, of course, is that it sounds good to you.  Double checking it on another (substandard) playback system is always helpful, however, to make sure the adjustments 'translate' well - for instance, listening on a crappy boombox or in your car.

-I do not think the spikes you see on the spectral analysis will give you the specific settings you want to apply so much as a guide of which frequency/frequency band is resonant and an indication of where to start with making adjustments.  Getting to the specifics, trust your ears and play with lots of alternative settings doing a/b comparisons until you get it 'dialed' in a way that sounds 'right' to you.

-Yep; applying a hpf is definitely applying EQ - though I would consider it more of a light touch in this case.
Title: Re: Reducing Bass in Post
Post by: T.J. on March 27, 2008, 12:57:57 PM
thanks again jim! it's funny to me that whenever i get some new equipment i end up learning something new.

i worked primarily with a small 5 minute section with heavy bass. i haven't applied it to the entire show yet, but i think i'm pretty dialed in. while doing this, in the back of my mind i was thinking, "how is this going to sound in my car?" b/c that's where i do most of my listening during the work commute. it's nice listening to my adjustments though a quality set of cans, but that's not always going to be the case.

i guess i have one last question about work flow. since i will be losing a little gain i plan on adding a little back. so what does everyone think abou this work flow:

24 bit file >>> HPF >>> add gain >>> fades @ beginning/end of each set >>> resample >>> dither >>> save 24 and 16 bit files (keep the original/untouched file too) >>> cdwave
Title: Re: Reducing Bass in Post
Post by: Dede2002 on March 27, 2008, 01:30:07 PM
thanks again jim! it's funny to me that whenever i get some new equipment i end up learning something new.

i worked primarily with a small 5 minute section with heavy bass. i haven't applied it to the entire show yet, but i think i'm pretty dialed in. while doing this, in the back of my mind i was thinking, "how is this going to sound in my car?" b/c that's where i do most of my listening during the work commute. it's nice listening to my adjustments though a quality set of cans, but that's not always going to be the case.

i guess i have one last question about work flow. since i will be losing a little gain i plan on adding a little back. so what does everyone think abou this work flow:

24 bit file >>> HPF >>> add gain >>> fades @ beginning/end of each set >>> resample >>> dither >>> save 24 and 16 bit files (keep the original/untouched file too) >>> cdwave

That's exactly what I do  ;)
Title: Re: Reducing Bass in Post
Post by: easy jim on March 27, 2008, 01:30:58 PM
i guess i have one last question about work flow. since i will be losing a little gain i plan on adding a little back. so what does everyone think abou this work flow:

24 bit file >>> HPF >>> add gain >>> fades @ beginning/end of each set >>> resample >>> dither >>> save 24 and 16 bit files (keep the original/untouched file too) >>> cdwave

Seems like the appropriate workflow to me.  8)
Title: Re: Reducing Bass in Post
Post by: T.J. on March 27, 2008, 01:39:54 PM
thanks gents another round of +t's in 12
Title: Re: Reducing Bass in Post
Post by: F.O.Bean on April 05, 2008, 09:15:50 PM
TJ, i use the VST MultiBand Compressor plugin and LOVE IT :) PM if you want it altho you already should :)