This thread is in part question and in part a memoir of an experience with me learning to ring out a room. As always, GIYF is not always spot on. So many ideas and half-baked advice can really mess up with you. For those who want to avoid foreplay, here's the question:

Have you ever rung out your rehearsal space or anywhere else where you use microphones? If you have, how do you go around it?

What i'm about to describe is two different ways to ring out a room based on my experience. Recently, I have bought my first digital mixer, an Allen & Heath Qu-16. I use the HUI mode capabilities to control faders, and mute and solo functions in my DAW. No biggie, but I also have a rehearsal space and I rent it for bands to practice. I have treated my room with rock wool panels and although it's no professional work, it's been working for me for the last four years. Anyway, once I setup the mixer, I needed to ring out the room and tame feedback loops. Cool.

ONE: I hired a professional live mixer friend to do the job. The mixer has all the tools for the job: a signal generator, RTA analyser, and a 31-band graphic equaliser all built in. My friend asked which mics I intended to use and then he started listening in for frequencies and then he started shaping the parametric EQ of each mic until they began ringing and compensated for it. once he found his sweet spot for each mic, he turned up the master fader until feedback started to appear. At that point, he started to notch down the parametric EQ filters until the room was feedback free. He moved several filters back and forth until done. It was quite an EQ curve! I didn't like the results. The system sounded weak and the sound wasn't right to my gut. He said that was the limit of my system and room. End of his story.

TWO: The next weekend, I played a gig and the sound man rang out the mics for the stage. Of course, I curiously peeped at his process. He took the lead singer's mic and aimed at the wedges. He started to get crazy ringing, but he moved the mic back until he isolated the main frequency prone to feedback and he lowered that filter. He did this two more times and he was done. Then he added the backing vocal mics, and the problem was minimal. A few notches here and there and the sound was awesome. We enjoyed the backline that night. Then I went back to the studio and replicated his method. I only needed to pull 7dB at 1.6k and 4 dB at 5k. That's all. All the 4 mics I use for vocals were left flat, ready to be EQ'ed at the singers' heart's content with plenty of headroom to pull up the gain in any mic if needed. I had previously set up the gain staging properly, with the master fader never going up beyond zero at any moment. BTW, 0 at the meter equals -18 dBFS, fixed.

CONCLUSION: I feel scammed by this 'friend' I hired. I know he knows his crap, he's been the sound man to countless gigs and he delivers. All I can conclude is that he took me for a long journey to justify his charging for a challenging job. What do you think?

Peace.

My rehearsal space/tracking room/makeshift bedroom when it's late to go home:

 

Last edited: May 27, 2016

Method One ignored the mic locations; thus it was next to impossible to wring (pun intended) the last dB of sweetness out of the room.

Method Two shows how the mics require a little bit of juggling around in order to get them out of place with a room's natural acoustic nodes and anti-nodes. Pointing the frontline mics at the foldback speakers and dealing with the ensuing howlround shows great savvy.

I would have done one more, tiny thing with PA at a venue. Pink noise test. Long time since I last set up a Rock PA at a live venue but I always used to leave a small amount of ringing in the sound whilst the audience space was empty. Then, when the crowds came in, their lovely soft clothing and squishy bodies soaked up the nastiness and left one with a nice crisp mid and top end.

 

Last edited: May 27, 2016

Always remember to wear ear plugs when tuning a room with loud pink noise. I found out the hard way. My ears rang for several days.

 

this is called ringing out the monitors, and should be done for every gig.
i am a live sound engineer and this is common practice you don't want a singer to be too quiet and then having to push them up to get terrible feedback. around 1k always seems to be a problem for wedges, although taking too much out can make them sound flat and lifeless.

i have never seen your friends method done. and it sounds stupid. having silly curves that are just going to make them selves sound stupid.
tailored rooms shouldn't need to have a 31 band for the p.a unless you have some serious ringing issues or standing waves.

but you should always have a 31 band on the monitors.

 

How do you use pink noise in testing the acoustics of a room? I've read the web, but Google doesn't seem to be my friend on this. I can't find a straight forward answer. Thank you for your time on this.

 

That's the great thing about Allen & Heath's Qu-16. I have ten master faders to run alternative mixes for different wedges and each one has a parametric and graphic 31-band EQ. And you get global RTA and signal generator. My room has only one pair of speakers for vocals, but if I wanted to add more speakers, I could have multiple graphic EQ settings. I'm sure other digital mixers feature the same, but this is my first digital desk. I couldn't be happier.

 

Did you discover the article at the link below...
http://hyperphysics.phy-astr.gsu.edu/hbase/audio/equal.html

 

Thank you, DF. Very simple and straight forward definitions.