EQ Techniques-Suggestions

[jkowtko]

A more experienced sound guy that came by a few weeks ago to help me EQ the room had a neat trick --

A CD with pink noise separated into the bands of the 1/3 octave EQ. Each track on the CD played a reference band alternating with one of the other bands, switching back and forth about once a second. Each track on the CD compared a different EQ band against the reference band.

This technique allowed him to select a CD track and tune each EQ band individually against the reference band. And you could definitely hear where the speakers were louder or softer than reference

If anyone else has used this technique I'd like to hear your thoughts.

Or, if there are other similar tricks out there that aid in balancing speakers in a room, please share!

Thanks. John

 

[SHARYNF]

The method you have described is now typically considered not to be a good idea

In general you use the Graphic eq as a way to eliminate feedback in monitors, and IN the MAIN FOH speakers to correct for non linearity in the speakers themselves, NOT to correct for Speaker/room interaction. Attempts to do this result in serious distorted response curves, and typically are only valid at a single point in the room if anywhere. In general you are looking for responses issues in the speakers/ or the cross over and attempting to eliminate the room from the measurement
As a rule, use acoustic treatment of the room or speaker placement to correct for speaker/ room interaction.

Sharyn

 

[mixmaster]

A more experienced sound guy that came by a few weeks ago to help me EQ the room had a neat trick --
A CD with pink noise separated into the bands of the 1/3 octave EQ. Each track on the CD played a reference band alternating with one of the other bands, switching back and forth about once a second. Each track on the CD compared a different EQ band against the reference band.
This technique allowed him to select a CD track and tune each EQ band individually against the reference band. And you could definitely hear where the speakers were louder or softer than reference
If anyone else has used this technique I'd like to hear your thoughts.
Or, if there are other similar tricks out there that aid in balancing speakers in a room, please share!
Thanks. John

John,
It is an interesting thought but I wonder how he decided on his "reference" bandwidth.
I prefer to hear the whole spectrum when listening to a room, so I can hear the effects of what I'm doing as it applies to the "big picture". You see, each bandwidth you adjust interacts with the ones on each side of it. If you just listen to, say 80 hz and compare it to 160 hz, then adjust the 160hz to match, you don't really know what's going on at 140hz. Even if your next comparison is at 80 and 140 you never hear 140 and 160 together. There can be all sorts of stuff happening there. The interactions between frequencies is sometimes called "color" (As in: You've overdone the EQ and colored up the mix.) I can see his technique as a tool for finding and working on a specific frequency maybe, but not for a whole room response. The best tool you have is your ear.
When I do a room with pink noise, I play the whole bandwidth, 20 hz to 20khz. I listen to the sytem and try to hear frequecies that stand out and notch them. At first you may need an RTA to help you visualize what's happening, but with practice you will tune your ears and learn to do it without the RTA. At that point you can say "the lower mids are killing me here" and work with a group of filters till you get it right. Eventually, you get to where you can hear a frequency and say "that's 250hz biting us, drop it by 3db" and all the young kids will look at you in amazment.
Play with it, and have fun.