Looking for a good resource for EQ adjustments for equal loudness

[tjmicsak]

Where can I find sort of baseline EQ adjustments for maintaining equal loudness at increasing DBSL?

I have the ISO 226:2003 revission graph but was wondering if there is any established rule of thumb when any source that sounds great at say normal room level then gets bumped by 1db increments up to any higher value for large venues.

I'm running a guitar into a MFX both direct to FOH and into a powered speaker for stage monitor and want to use an outboard EQ between the MFX and powered speaker to maintain the sounds of the program patches while they get louder than the room volume they are made in. I want to maintain equal loudness so those presets maintain that same sound through low to high volumes.
Right now when I get loud they are getting way too high end and low end heavy so I obvioulsy boost some mids but with a chart of some sort for each octave through the spectrum I would know exactly where to cut on a graphic EQ based on the db level percieved changes.
Then I could further tweak for the room changes from that baseline I establish.

 

[Rex Anderson]

You can look at Fletcher Munson equal loudness contour curves, but it will be very hard to use for live sound purposes.

The ear is most linear around 85 dB SPL. We rarely listen at that level unless you are in a studio and are mixing and know to work at that level.

In live sound, it's pretty much mix at the level you want and use your ears to determine how much bass and treble (low end and high end) you need to balance with the mids.

A good tech will tune the system in the room so it is fairly flat, but not crazy with the amount of top octave.

The system will limit to a large degree what is possible anyway with producing deep bass (lowest octave or two) and you don't really want the top octave too bright or sizzly.

Maybe a good way to work would be to develop your patches in a more real world environment with your monitor and mains at real world SPL's rather than on headphones or with your monitors at low SPL's. At least try creating your sounds at 85 dB SPL.

 

[tjmicsak]

Thanks for the great advice.

 

[Rex Anderson]

Here's a few more thougths after I mulled it over last night.

You have been making your sounds at too low volume because you are applying the "loudness button curve", adding bass and low end to compensate for working at low volumes.

There is a methodology to calibrate your monitoring level so you can mark you playback volume knob and have a reference.

Go to Bob Katz's website, digido.com (Digital Domain mastering). He has a good read on playback level calibration and describes how to do it and gives you a band limited pink noise .wav file to use. You need an SPL meter. Radio Shack analog meter works OK.

Once you get on to how it works, it will change your way of working so you don't have the problems you are experienceing now.

An easier way, though not as accurate, is to play a well mastered CD through your system (I use Donald Fagen's "Morph the Cat") and set your playback volume control so it averages around 85 dB SPL on the SPL meter (C weighting).

If you create your sounds working at this level, they should hold up pretty well at louder volumes, though you may need to add bass and treble it you are playing live at lower volumes (doubtful that you will be gigging at that level).

 

[barhrecords]

+1 on Bob Katz's monitor loudness calibration and advice about levels.

I just leveled the monitors in my mix room using his white paper advice.

He advises to playback -20dbFs pink noise and calibrate the loudness of each speaker to read 83db SPL C weighted slow response from the listening position.

Mark that as your "0" setting.

Mix (aka create patches) at -6 from that or 77db SPL.

I found a K-Meter plugin that has the pink noise generator builtin and the Katz style metering.

http://www.vsonics.com/vmeters.php

Note: You will need FXpansion's VST -> RTAS wrapper to use this in Pro Tools.

The idea is mix and create your patches at a known loudness. That will let you compare apples to apples.

Richard