# "smart" bass limiting/limiter - do such circuits/programs exist yet?



## VERTIGGO (Feb 20, 2009)

I've narrowed down 2 common "annoyances" I've experienced with every audio system I've set up so far:

1 - some albums are mixed with obnoxiously strong bass tracks

It's most noticeable when I pop in most Brian Setzer or even some early Bowie stuff - usually the bass guitar (sometimes kick drum) is mixed so loud I have to constantly switch the EQ (normally in the car on this one) between "vocal" and "super-bass" etc. I assume this is because most people have rolled off response in the lower ranges so artists mix these instruments at higher levels to compensate.

2 - some of these tracks sound like they're just mixed badly and there's a constant resonant frequency that drowns the intonation of the bass

I've only heard this on Brian Setzer's "Red Hot n Live" album. The double bass kicks hard but seems to be badly mic'd or something, since the notes are difficult to differentiate... it just sounds like a mono-tone drum.

Now I'm guessing these are related issues, but I'm hoping for a solution short of editing dozens of .mp3's with Audacity! I guess setting up BFG profiles or something would work as a manual fix, but the point is I don't like having to keep messing with the controls whenever the song changes.

Has anyone heard of or used any kind of equalization that intelligently pulls certain frequencies down (whether specific as in equalization or even just the lower ones in general) only when they cross a certain threshold?


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## GranteedEV (Aug 8, 2010)

A compressor such as this:

http://www.zzounds.com/item--ALE3630

should do what you're asking (may be a learning curve though)....however...I'd still evaluate the measurable accuracy of the reproduction system itself, over multiple seating positions, from 20hz to 300hz with 1/12th of an octave resolution. There is always the possibility that in fact the system is at fault.


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## VERTIGGO (Feb 20, 2009)

Please forgive my noobness here, but how can the system be at fault? Are you saying that the trunk/cabin resonance is deceiving me into thinking certain artists' music is just more "bassy"?

I had thought it was out of the question for the first problem because certain songs are really heavy even though the notes are all over the place---though if the instrument's resonance happens to match my own listening environment I could see that affecting it every time it's plucked...


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## GranteedEV (Aug 8, 2010)

VERTIGGO said:


> Please forgive my noobness here, but how can the system be at fault? Are you saying that the trunk/cabin resonance is deceiving me into thinking certain artists' music is just more "bassy"?


...Have you measured the frequency response inside the car??

You'd be surprised how bad bass response in is in most environments without EQ.

Notes are not individual frequencies... they are made up of fundamentals and harmonics, which span the entire 25hz to ~250hz span. I would not be even remotely surprised if you had response tolerance +/- 20db. It's more than just a single resonance. It's things like standing waves and pressure vessel gain, as well as the native response of the speakers. The final result may be nothing like you predict.

I would advise you to invest in some measurement gear (calibrated mic + USB Sound card). Once you've measured what's actually going on, you can address the specific issues.


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## VERTIGGO (Feb 20, 2009)

GranteedEV said:


> ...Have you measured the frequency response inside the car??
> 
> You'd be surprised how bad bass response in is in most environments without EQ.


No that's a problem, I know, the car's response is bad in certain places, I just didn't think this issue could be completely based on response. I have a BFG, but I don't know where I could fit it in there---I guess it could be fastened in the back with the amp.

If you're curious, I'm currently using the 15" from my DIY build in a sealed box (about 3^2 feet).


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## GranteedEV (Aug 8, 2010)

VERTIGGO said:


> No I know that's my first mistake, I just didn't think my issue could be completely based on response. I have a BFG, but I don't know where I could fit it in there---I guess it could be fastened in the back with the amp...


response below shroeder frequency is always the first culprit to look at, before worrying about other things. Of course there's other fundamental issues (the behaviour of the system itself) that shuold not be ignored.

If a BFD is too large, consider a miniDSP which can be run off of 12V and is small. A few people have had good success with them.


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