How do I RTA and EQ to obtain flat response?

[Paul]

I am a QU-16 newbie. I’ve got the basic mixer navigation down, and now I am ready to start tackling the more advanced stuff.

I am currently trying to set the EQ response flat using RTA and a RTA mic. So far I’ve managed to output a pink noise signal to the speakers, plug in a RTA mic into one of the channels, turn on the phantom power, and get it working. And then I got interrupted last night, so I will be taking it up again this evening after work. Last night once I got the mic plugged in I pointed it at the speakers, but when I went to look at the RTA signal it didn’t seem to display any output. What am I missing? Is there some routing issues I need to tweak? What are the steps? Thanks,

Paul

BTW, I love the board so far. I am getting pretty excited about putting it into production.

[Anonymous]

WOW
What a very subjective can of worms you are opening up here.
However GOOD on you for asking this question.
I will watch with enthusiasm.
I used to do this (tune the PA to a display) once upon a time by watching the graph
until singer came up to me at a job and asked “please turn down the treble!”
I thought what? sounds fine to me…
Those were the days of self tutoring reading the Yamaha Sound Reinforcement Book.(The old black book that cost $140! One of the “sound Bible’s” from my era

I think the RTA is really handy for foldback!

[Nicola A&H]

Hi Paul,

The RTA follows PAFL selection. Make sure your measurement mic is PAFL’d and the gain structure right.

When using GEQ Fader Flip on any Mix or LR, you can also see the RTA on the fader strip meters, matching the frequency bands on faders, to help you identify frequencies and tweak accordingly.

Hope this helps.

[Paul]

Nicola,

Thanks for the tips. I pecking away at this in snatches of time, and I think I am closer.

I am trying to RTA the LR mix for starters. With the RTA mic channel I was having feedback issues which I solved by turning off that channel for the LR mix (duh). I then had to turn up the gain and fader quite a bit to get the gain structure right for the channel. I PAFL’d that channel per your tips. I could then see the RTA level registering and was seeing a pretty flat response with tapering to zero on both ends (what I should see, yes?).

I then got it into GEQ Fader Flip mode but was not seeing that changing the GEQ was having any effect on my pink noise as the RTA output remained static. And that was as far as I got. Riding into work on my bike this morning, it occurred to me that maybe GEQ was toggled off for the LR mix. I will check that next.

Getting closer! …

Once I get over the learning curve, if this is as easy as I think it is, it’s going to rock. I just do sound for my own band, so I am always behind the FOH speakers. RTA-EQing has saved our a**es many a time. Where it’s not as good as a pro soundman, it’s way better than guessing from the stage and can give you a great starting place.

[Paul]

Yes indeed, I got it working and the only problem left to tackle was that I had the GEQ toggled off for the LR mix. I could then hear and see the effects of changing the GEQ on the RTA output.

Once I’ve done this a few times and am over the learning curve, I think it should be pretty painless and efficient to use. I can just save my settings for the measurement mic channel along with the rest of my mix, so I don’t have to start from scratch.

I should take the time to write up a recipe for how to do this, if someone hasn’t already.

[Billy]

Hi Paul thanks for your posts. i would like to understand this process as well and am starting from scratch. If you can post a recipe for this it would be great. . . or even better would be a youtube video showing how you do it!

[mamerica]

Take a look at this video. On it, Dave Rat, a very well respected sound engineer and one of my personal heroes, explains how to EQ a system with nothing more than a good pair of headphones and a good set of ears.

Hope this helps.

[Billy]

Ok thanks I will check that out tonight.

Paul – what RTA mic are you using? Have you tried using an RTA app on an ipad/iphone?

[Author]

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