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Author Topic: How to properly use the RTA for eq-ing the PA?  (Read 22021 times)

Sayan Ghosh

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How to properly use the RTA for eq-ing the PA?
« on: May 13, 2012, 02:23:50 AM »

This is my first post in PSW. I work for an audio rental company. I have never gone to an audio engineering school, kind of self and internet taught.

One thing that i would like to know is how to properly read an RTA(say SMAART) and eq the PA. Because everytime i have tried tuning the system using the RTA and chopping down the frequencies that are peaking, i seem to get an eq shape that looks pretty weird and it makes me feel like this can't be what you call a properly tuned PA. I trust the sound of my voice through an SM58 more for eq-ing the system. I seem to get a more natural sounding PA.

It might be absolutely my inefficiency in using the RTA that i can't really get to sound the PA natural and more often than not i seem to chop down the 100 120hz as the RTA show those two frequencies peaking at almost all venues. So i would really appreciate if someone could tell me how exactly to read the RTA and eq the PA accordingly.
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Langston Holland

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Re: How to properly use the RTA for eq-ing the PA?
« Reply #1 on: May 13, 2012, 02:30:23 AM »

Hello:

The PSW forums require you to post using your real name - thanks. :)
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God bless you and your precious family - Langston

Sayan Ghosh

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Re: How to properly use the RTA for eq-ing the PA?
« Reply #2 on: May 27, 2012, 01:54:48 AM »

Bump!
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Patrick Tracy

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Re: How to properly use the RTA for eq-ing the PA?
« Reply #3 on: May 27, 2012, 02:49:44 AM »

Although SMAART may have an RTA function in it that isn't the best tool for system tuning. Since RTA operates in real time (as in Real Time Analyzer) it can't distinguish the direct sound of the system from the indirect sound of the room. That's why you get results that don't sound right. You need to use the tools in SMAART that do make a distinction between the direct and indirect sound. And although you can adapt the system to the room somewhat, you can't truly fix room issues with signal processing.

Ivan Beaver

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Re: How to properly use the RTA for eq-ing the PA?
« Reply #4 on: May 27, 2012, 08:29:42 AM »


One thing that i would like to know is how to properly read an RTA(say SMAART) and eq the PA. .
The FIRST thing you have to do is to erase your mind of the word (and tool) RTA.  Yes it has a few applications-sound system alignment is NOT one of them.

You will find all kinds of posts on this and other boards about how frustrated people are with trying to use an RTA to "tune" their systems.

This is because you are using the wrong tool.

I would argue that a large number of people using Smaart are only using the RTA function-which is WRONG!

This is probably due to the fact that using the TRANSFER function is "more work" and takes a greater understanding.  HOWEVER that is the RIGHT tool-and doing things PROPERLY often takes a bit more effort than the "quick/automatic" way out.

There are THREE sides to the whole measurement process.  The EASY one is learing how ot operate the program (be it Smaart-Systune-EASRA-TEF or any of the various other platforms).  The HARD part is understanding what the program (through the various "displays" (such as amplitude-phase-impulse etc) are telling you. And the third (also the hard part) is knowing what you can and CANNOT DO to improve/change things that are displayed.

You have to know if you have GOOD DATA.  Just because it is shown on the screen DOES NOT mean that it is real.  You have to dig a bit deeper to know that.

It is NOT a simple do this-then do that type of thing.  Those of us that have been doing it for awhile-realize more and more everyday what the various programs are showing us.

ALSO the program will NOT tell you what you to do to "fix" the problem you may see on the screen.  If you have good data (that is the first hard thing to do for most people-having a good measurement position) then it is UP TO YOU AND YOUR KNOWLEDGE to go about "fixing" the problem.  THEN the program will tell you if you have done it right or wrong. FOR THE PARTICULAR MEAUSREMENT POSITION. 

I CANNOT STRESS that enough!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!  Just because it "appears" you have fixed the problem in one spot-can ALSO mean that you have actually MADE IT WORSE in others!  That requires MORE measurement positions to be sure that are are actually fixing something that can be fixed.  Another of the "hard" parts.

The FIRST thing you have to do is to get the program-start making measurements- READ ALL of the tutorials available.  Post measurements on forums and have people critique them.

It is a lot harder than most people realize-and takes awhile to even start to understand what the programs are telling you.

HOWEVER you will get better results out of it.

Have you already forgotten the RTA?  if you haven't- STOP USING IT!




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Timo Beckman

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Re: How to properly use the RTA for eq-ing the PA?
« Reply #5 on: May 27, 2012, 11:58:05 AM »

The FIRST thing you have to do is to erase your mind of the word (and tool) RTA.  Yes it has a few applications-sound system alignment is NOT one of them.

You will find all kinds of posts on this and other boards about how frustrated people are with trying to use an RTA to "tune" their systems.

This is because you are using the wrong tool.

I would argue that a large number of people using Smaart are only using the RTA function-which is WRONG!

This is probably due to the fact that using the TRANSFER function is "more work" and takes a greater understanding.  HOWEVER that is the RIGHT tool-and doing things PROPERLY often takes a bit more effort than the "quick/automatic" way out.

There are THREE sides to the whole measurement process.  The EASY one is learing how ot operate the program (be it Smaart-Systune-EASRA-TEF or any of the various other platforms).  The HARD part is understanding what the program (through the various "displays" (such as amplitude-phase-impulse etc) are telling you. And the third (also the hard part) is knowing what you can and CANNOT DO to improve/change things that are displayed.

You have to know if you have GOOD DATA.  Just because it is shown on the screen DOES NOT mean that it is real.  You have to dig a bit deeper to know that.

It is NOT a simple do this-then do that type of thing.  Those of us that have been doing it for awhile-realize more and more everyday what the various programs are showing us.

Have you already forgotten the RTA?  if you haven't- STOP USING IT!

I second this .
The rta mode within SMAART only runs during show time during all jobs i do for SPL levels and every now and than to locate feedback problems sometimes .
For the rest of it i'll only use the tranfer function .
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John Roberts {JR}

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Re: How to properly use the RTA for eq-ing the PA?
« Reply #6 on: May 27, 2012, 12:57:56 PM »

The RTA is a measurement tool and you need to understand the limits of that measurement.

It can tell you the frequency response for that one mic in that one spot, but this is a little like the ten blind men trying to describe an elephant by feel.  It doesn't give you the whole picture for the entire room, just one spot measurement.

Taking multiple measurements from different spots and averaging the result helps but simply combining multiple mics can cause other issues with summation.

So it is not completely worthless, but be careful about following it too literally.

JR
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Ivan Beaver

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Re: How to properly use the RTA for eq-ing the PA?
« Reply #7 on: May 27, 2012, 02:34:28 PM »

The RTA is a measurement tool and you need to understand the limits of that measurement.

It can tell you the frequency response for that one mic in that one spot, but this is a little like the ten blind men trying to describe an elephant by feel.  It doesn't give you the whole picture for the entire room, just one spot measurement.

Taking multiple measurements from different spots and averaging the result helps but simply combining multiple mics can cause other issues with summation.

So it is not completely worthless, but be careful about following it too literally.

JR
Totally agreed.  And as Timo says-there are some applications.

But I bet most people who are "attempting" to use an RTA-are not using it for the proper applications.

As with ANY measurement-you have to understand the limitations of what it can and cannot do-at least accurately.

System alignment is NOT one of those applications.
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A complex question is easily answered by a simple-easy to understand WRONG answer!

Ivan Beaver
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ProSoundWeb Community

Re: How to properly use the RTA for eq-ing the PA?
« Reply #7 on: May 27, 2012, 02:34:28 PM »


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