Rational Acoustics



Jivey1303
May 10th, 2011, 01:19 PM
The other day I had the privilege of working with a very experienced FOH engineer, who tunes everything by ear rather than with measurement systems. We had a fairly simple rig with 9 boxes of Nexo GeoT a side, Nexo S12 front fills, and 4 Nexo S2 subs per side. Nothing crazy. Now as he was tuning the rig he mentioned that he uses one track to test the concussion of the PA and to dial it in. Then uses another track to dial in the stereo imaging of the PA. Now at no point did we make any adjustments to our hangs or splay angles.

So my question is: How do you tune a PA to have better stereo imaging without re-assessing your rigging points? Is it merely a matter of dialing in the high frequencies to ensure that the various reflections aren't being covered up by other areas of the spectrum that are overly present?

How do you tune for concussion? Again, is it merely dialing in the mids and lows to ensure things aren't being covered up?

I didn't get the opportunity to ask, so I figured I would try here first.

Thanks,

J>R

Arthur Skudra
May 10th, 2011, 04:35 PM
So my question is: How do you tune a PA to have better stereo imaging without re-assessing your rigging points? Is it merely a matter of dialing in the high frequencies to ensure that the various reflections aren't being covered up by other areas of the spectrum that are overly present?Maybe he was doing something else, but correcting an issue in the time domain is completely different than correcting something in the frequency domain. Awfully difficult if not impossible to do anything like this by ear. IMHO Stereo imaging, or any kind of imaging issue has a time element involved, not something you can tweak an eq knob to change. Maybe he was just tweaking the HF to bring a bit more presence to the mix? Hard to say.


How do you tune for concussion? Again, is it merely dialing in the mids and lows to ensure things aren't being covered up?
Hmmm, concussion is the phenomenon that occurs to my head when someone cranks the system up to 125 dB SPL and I don't have my earplugs in!!! But I digress! LOL :D
I think you're maybe talking about transient response and/or tightness of the low end? A number of factors at play, including room acoustics, speaker design, careful LF optimization, amp selection, heavy enough wire gauge to the speaker to take care of damping to name a few.

Arthur Skudra
May 11th, 2011, 10:57 PM
Excellent new article here that's very relevant to this thread:
http://www.prosoundweb.com/article/conventional_wisdom_i_can_eq_a_sound_system_better _by_ear/

Jivey1303
May 12th, 2011, 11:02 AM
Arthur, Thank you for your response. I too was still very confused and didn't have the time to dig further. We were at an outdoor venue, basically and open field with a traditional roof...nothing crazy. Tweaking the EQ was all that I could think off. I'm a young gun that fully understands the physics and computer based measurement side of the equation. Just trying to balance with the science with the art of the old guard.

I appreciate your input and thank you for the article.

PrestonSoper
May 21st, 2011, 05:48 PM
Here is another relevant article.
http://www.prosoundweb.com/article/when_hearing_starts_to_drift/

Kip Conner
May 26th, 2011, 11:37 PM
J-R, how did it sound to you? Curious if you thought it sounded both concussive and imaged?

I applaud the efforts of people who can tune a PA by ear, I, myself, cannot hear things such relative phase between two drivers. I can hear dips at the acoustic crossover, but could not tell you if the driver was out of polarity or the speaker just lacked a usable frequency response.

it also helps that you gave him a decent PA!