System tuning with minimal tools (and skills)

L

Loren Jones

Sophomore
Jun 25, 2011
155
0
16
Hampton Roads VA
Perhaps this has been discussed but I didn't find it on a search.

My only tool for "measuring" the output of the PA at church is StudioSix Digital's RTA software for iphone/ipad. With that as the only tool my method has been to put the RTA on "average" and walk the room back and forth and side to side for 3-4 minutes with pink noise on in the system. I have then used the resultant RTA plot to help guide EQ settings. I have then listened to some music through the system and through some decent headphones as a reality check. I think it sounds pretty good but am always looking to try to get the best possible.

Is there a better method to use with the tools available to me?

FYI, the manufacturer recommended crossover and parametric DSP settings are applied to the system prior to this "tuning" being undertaken.

Thanks for any advice here.
 
Re: System tuning with minimal tools (and skills)

Adjusting a PA based on measurements made with uncalibrated equipment seems like such a waste of time.

Most shows I have a DEQ2496 with a dbx measurement mic. This is mostly for SPL level monitoring. The RTA function impresses the tourists I find it of little use in live sound.

My Goldline RTA seldom sees the light of day anymore.
 
Re: System tuning with minimal tools (and skills)

Tim Perry said:
Adjusting a PA based on measurements made with uncalibrated equipment seems like such a waste of time.

.
Click to expand...
To be honest-I can't think a single alignment I have ever done-in which I "calibrated" my measurement rig.

I really don't see a need for it. After all-what I am concerned with is the DIFFERENCE between seat to seat (relative level)-NOT what the absolute level is.

I totally agree that an RTA is pretty much worthless in sound system alignment.

BUT there are times in which is comes in very handy. Such as rooms that have a long reverb time. I use it (much better than a dual transfer or swept freq) to excite the room, then mute the audio and watch the display (with a fast decay time) die away. If there is one freq area that really stands out (in most rooms there is-not a well designed concert hall for example). Then I put a dip in the response around that area and re test.

Yes when you measure this with a dual FFT or swept type measurement, you will see the "hole". However when you listen to it with music or speech, the room will not get as "excited" at those freq, and since they tend to hang around longer-now they are less of an obvious "issue". Of course you have to play with it a bit to get it where you need it-which is a compromise between flat response and long reverb time.

Yes this can change when the room is full of people-something else that needs to be considered. Don't chase "perfection" in a empty room of that type.
 
Re: System tuning with minimal tools (and skills)

Ok, we'll it seems I'm just wasting my time then for the most part then. Fair enough. I guess we'll just go with the ears and some reference music and take what we get. It's not hypercritical in any case. Thanks guys for the input.

Loren:)~:)~:smile:
 
Re: System tuning with minimal tools (and skills)

I think we might have some semantic differences at play here. We routinely "voice" a system with our ears... we want it to sound "right". That's all VERY subjective - the LF haystack that is a virtual requirement for American rock and roll would be very out of place for other genres or styles. The voicing that sounds perfect for the jazz quartet wouldn't work for rock. This is the reason I try to voice systems in a way that is linear - what comes out of the desk, electrically, is what comes out of the speaker system, acoustically.

"Tuning" seems to have different meanings. Ivan makes that term mostly synonymous with "alignment," while other folks might think it more in line with voicing.

My question, Loren, is what is the goal of your process (whatever it might best be called)?
 
Re: System tuning with minimal tools (and skills)

Tim McCulloch said:
I think we might have some semantic differences at play here. We routinely "voice" a system with our ears... we want it to sound "right". That's all VERY subjective - the LF haystack that is a virtual requirement for American rock and roll would be very out of place for other genres or styles. The voicing that sounds perfect for the jazz quartet wouldn't work for rock. This is the reason I try to voice systems in a way that is linear - what comes out of the desk, electrically, is what comes out of the speaker system, acoustically.

"Tuning" seems to have different meanings. Ivan makes that term mostly synonymous with "alignment," while other folks might think it more in line with voicing.

My question, Loren, is what is the goal of your process (whatever it might best be called)?
Click to expand...

Much more in line with voicing. As you stated I want a source to sound as natural and uncolored as possible though the system. So if I PFL some channel with good headphones I want it to sound as similar as possible through the loudspeakers. And I want that to hold as true as possible for as many seats as possible. This is my goal. I chose to use what "tools" I have the way I did because it seemed to me a reasonable way to try to average the sound across as much of the auditorium as possible. In doing this I did leave the subs a good 6-8 db higher than the rest and shot to smoothe out other major anomalies. So I am aware that I don't have the knowledge and gear to even begin system alignment so just mfr suggested x-over and parametric settings in the DSP are the extent of "alignment" for our system and I am just trying to adjust the voicing a bit I guess. I know we would benefit from having a skilled person like Ivan (or any number of others here) come in and align and voice our system. I have suggested it many times and it will not be embraced mostly because it is "good enough" for our church purposes. Anyway, that can of worms isn't one I hope to open here.

thanks Tim
 
Re: System tuning with minimal tools (and skills)

Your RTA app may come in useful if you use it to quickly identify feedback frequencies.

Reading the software blurb, it seems you can calibrate the SPL reading provided you have a known accurate meter to reference it against. You are still at the mercy of whatever frequency response the built in mic of your device has... kind of like measuring wind speed by spitting on your finger and holding it up.
 
Re: System tuning with minimal tools (and skills)

Tim Perry said:
Your RTA app may come in useful if you use it to quickly identify feedback frequencies.

Reading the software blurb, it seems you can calibrate the SPL reading provided you have a known accurate meter to reference it against. You are still at the mercy of whatever frequency response the built in mic of your device has... kind of like measuring wind speed by spitting on your finger and holding it up.
Click to expand...

I may be wrong but I thought the app used some corrective EQ for typical iPhone mic anomalies. Even if they did the consistency on those is obviously going to be nonexistent. And that's before they have been dropped in a cup of coffee.
 
Re: System tuning with minimal tools (and skills)

Tim Perry said:
Your RTA app may come in useful if you use it to quickly identify feedback frequencies.
Click to expand...

Absolutely. Extremely fast for ringing out. I needed to use 2 podium mics in a tough situation with an LS9. I was able to place four notches in about two minutes and have it be both stable and usable.

I use the "Audio Tools" app for droid which identifies the strongest frequency both numerically and graphically. Very handy.
 
Re: System tuning with minimal tools (and skills)

Dave Rickard said:
I use the "Audio Tools" app for droid which identifies the strongest frequency both numerically and graphically. Very handy.
Click to expand...

Any chance of a link? I did a search on Google Play and didn't find this one specifically (found "AV Tools" and "Audio Toolkit", but by their descriptions, I didn't get that either is what you're using).

-- Mitch
 
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