Which Frequencies to Frequent the Most Frequently?

**aj113** · 06-30-2012, 03:37 AM

Do certain frequencies take up more of that precious limiter headroom than others? My ears are telling me that the lower frequencies take up a lot more real estate than the higher ones. Is that right, or are my ears just jerking themselves off?

**Jeronimo Mora** · 06-30-2012, 04:13 AM

That's my understanding. I made a small parametric cut to lowest of the low frequencies on my master bus and I got it like 1-2 db louder instantly. It kind of makes sense too. If you look at a frequency response curve of a song, you'll tend do see a negative slope from low to higher frequencies. Our ears are more sensitive to the upper midrange, so I guess we require much less of it in a mix than low end. But the computer is equally sensitive to all frequencies. It recognizes that there is X of this frequency and Y of this frequency. Which lends itself to the amount of low end being present affecting limiting. The more balanced the mix is, the louder it will be. If the curve had the opposite slope (more high end) it would REALLY hurt. Ignoring that, in this scenario, the high end would be the one taking up all the real estate.

Just my conspiracy theory. Hope I'm right hahaha.

**garww** · 06-30-2012, 04:15 AM

Bass is a energy hog. I don't think you can get into engineering school without understanding that. You simply mute your bass heavy tracks and watch your level meters go on lunch break to roll some transients at the bus station.

**fHumble fHingaz** · 06-30-2012, 07:16 AM

My ears are telling me that the lower frequencies take up a lot more real estate than the higher ones.

As I understand it, this is related to the sensitivity of our hearing at different frequencies... Bass needs more volume (& thus energy) to be perceived as equaling the level of instruments further up in the midrange where human hearing is most sensitive.

The original studies done into this developed the "Fletcher-Munson" curve describing relative sensitivity to frequencies - There is quite a bit of information on Wiki about it: Equal-loudness contour - Wikipedia, the free encyclopedia

**acidfrost** · 06-30-2012, 07:17 AM

Low frequencies will take more of the limiter headroom, you're right.
Also, Highs will take less headroom but will give the illusion of being louder when raising them. So if you bring up the top end on a vox track, You won't get much db but you'll hear the illusion of the vox being louder.

**aj113** · 06-30-2012, 08:28 AM

OK got it - so in summary, bass frequencies at face value don't take up any more headroom, but because we need more of them in order to hear them as well as we hear mid/high frequencies, then typically they DO take up more headroom?

**brandondrury** · 06-30-2012, 09:08 AM

As I understand it, this is related to the sensitivity of our hearing at different frequencies...

That's half of it. The other half is getting that big, damn woofer to move takes some serious energy. When compared to that little bitty tweeter, the woofer is a dump truck. Between the two, we just need a crap load more low end energy to get where we are going.

If you look at a frequency response curve of a song, you'll tend do see a negative slope from low to higher frequencies

I've been analyzing a lot of modern house/electronic whatever stuff (Dada Life, Deadmau5, etc) and 85% of the time I'm seeing a BUNCH in the 40-50Hz range, a dip in the 80-160Hz range and a slow and almost linear rise up to about 10k where it drops off again. Food for thought. Not sure what that's worth in the big picture.

If the curve had the opposite slope (more high end) it would REALLY hurt

Be a little careful with this or at least apply a certain "opacity" to the concept. The pain stuff generally kicks in at 2k-5k.

OK got it - so in summary, bass frequencies at face value don't take up any more headroom, but because we need more of them in order to hear them as well as we hear mid/high frequencies, then typically they DO take up more headroom?

Yeah, that sounds about right to me.

Brandon

**garww** · 06-30-2012, 10:31 AM

Originally Posted by aj113

OK got it - so in summary, bass frequencies at face value don't take up any more headroom, but because we need more of them in order to hear them as well as we hear mid/high frequencies, then typically they DO take up more headroom?

You can use the data about the ears abilities - like F-M at low listenting levels - but it's not just about hearing it. There is a relationship between volts and current and that is all our gear can deal with( or fry)

A speaker box will have a limiter in the form of a fuse. This is to protect the driver coil wire from overheating and carboning-up or burning through. In practice, it protects against bass frequencies. A flute or recorder note could fry your tweeter. but, generally, bass is the demon. Typically, in a 60 year old car or a modern home stereo, you can increase the preceived headroom by turning the bass down.

With bass processing in modern pop/rock, you may want to envision a 6-pack ab muscle commercial. By trimming away what might not be needed, you can make better use of your heavy processing as there is less to process. You could practice you limiting skill on a hi-quality pipe organ recording that typically hits 15-25Hz and also has recorder(instrument)-like energy levels in the higher registers

**bobbybovine** · 06-30-2012, 11:40 AM

Most of this can be explained by the Fletcher Munsen Curves. Fletcher Munson Curves - Wikipedia
To summarize it takes more energy (louder db level) for bass to sound as loud as 1k to 10k range. Take into consideration what garww is saying as well from the electronic aspect, it also physically takes more energy to move a 15" woofer than a 1" tweeter.

edit: Sorry fHumble, didn't realize you already said what I postedf.