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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => Audio Measurement and Testing => Topic started by: kendallhadden on April 27, 2015, 02:49:12 PM

Title: Dual Channel Analysis Help
Post by: kendallhadden on April 27, 2015, 02:49:12 PM
Hello everyone!  I have a few questions about dual channel analysis.  As a preface:
Before upgrading to my current system, I used a Driverack Auto EQ to help set my sound.  After reading here and talking to different people that know way more than me, I decided to make some upgrades and totally pull the Driverack from my system.  I now use a Xilica XP4080 for DSP and the quality of my sound has gotten exponentially better. 

The main use of my sound system is for my christian vocal band.  We generally are booked in different venues Friday night, Saturday night and Sunday morning and night.  So many times we don't have a lot of time to really tweak the sound. 

Recently I helped supply sound for a Brandon Heath concert.  The sound engineer brought in his computer, hooked up an interface and a Reference mic and used SMAART to analyze a raw audio signal directly from the board into the interface and compared that to the audio coming from the speakers using the Reference mic.  He then used the EQ to adjust the main audio to try to match up the measurements of the two.  This was a relatively quick process and he didn't have to use pink noise.  He just used a high quality recording.  After some research, I read about SMAART DI and that seems to do what I want.  But it is pretty expensive.

I will spend the money if necessary, but I'm curious if there is another program/hardware that will do the same process for less than SMAART and would be just as effective.

Thanks for any  help or input you can give.
Title: Re: Dual Channel Analysis Help
Post by: David Sturzenbecher on April 27, 2015, 02:54:46 PM
Hello everyone!  I have a few questions about dual channel analysis.  As a preface:
Before upgrading to my current system, I used a Driverack Auto EQ to help set my sound.  After reading here and talking to different people that know way more than me, I decided to make some upgrades and totally pull the Driverack from my system.  I now use a Xilica XP4080 for DSP and the quality of my sound has gotten exponentially better. 

The main use of my sound system is for my christian vocal band.  We generally are booked in different venues Friday night, Saturday night and Sunday morning and night.  So many times we don't have a lot of time to really tweak the sound. 

Recently I helped supply sound for a Brandon Heath concert.  The sound engineer brought in his computer, hooked up an interface and a Reference mic and used SMAART to analyze a raw audio signal directly from the board into the interface and compared that to the audio coming from the speakers using the Reference mic.  He then used the EQ to adjust the main audio to try to match up the measurements of the two.  This was a relatively quick process and he didn't have to use pink noise.  He just used a high quality recording.  After some research, I read about SMAART DI and that seems to do what I want.  But it is pretty expensive.

I will spend the money if necessary, but I'm curious if there is another program/hardware that will do the same process for less than SMAART and would be just as effective.

Thanks for any  help or input you can give.

There are many others...  I have experience with a similar slightly cheaper option being EASERA Systune
Title: Re: Dual Channel Analysis Help
Post by: Chris Tsanjoures on April 27, 2015, 04:32:06 PM
There is a program called REW (Room Eq Wizard) which is freeware and supposedly a reasonable place to start for basic transfer function measurements. I don't have any experience with the Systune offerings. There is a demo of Di and v7 available on the Rational Acoustics website, they will both expire after 30 days from launch.

Title: Re: Dual Channel Analysis Help
Post by: Lyle Williams on April 27, 2015, 06:05:56 PM

I don't think REW does real time TF.  I could be wrong.

My cheap and compact transfer function rig is:

Calibrated Mic: Dayton EMM-6
Interface: ART USB Dual Pre
Platform: iPad Mini
Software: Studio Six Digital's AudioTools, with Transfer Function in-app purchase.
Title: Re: Dual Channel Analysis Help
Post by: Jeremy Young on April 30, 2015, 12:38:23 AM
I've got the same setup as lyle, works great, except mine is an iPad 2, which i also use to control my mixer.  very inexpensive if you already own the tablet.
Title: Re: Dual Channel Analysis Help
Post by: Timo Beckman on April 30, 2015, 01:01:35 PM
Speaking for my self i'm happy to have switched over from SIM3 to Smaart7. I do have SIM3 available within my company and use it every now and then along with galileo or when i'm asked to use it.

I have tried sys tune but couldn't get it to work properly which has more to do with me then sys tune (windows and little old me are no friends when it comes to audio). The same goes for LAMA which i also tried but took to long to configure and to get it working properly.

I also have a program called SAT-live which i used along smaart5 before i started working on SIM (tried it again a couple of months ago and i still like it) but Smaart will be and stay "my preferred analyzer". Has to do with the speed of the program multi channel transfer measurements and averages of multiple transfers live on screen among other things.

If you get the chance attend a seminar by one of the rational instructors or maybe a seminar by magu (meyer sound). These seminars are not free but definitely money well spent.
 
Title: Re: Dual Channel Analysis Help
Post by: Lyle Williams on May 02, 2015, 01:04:14 AM
Smaart is undoubtedly better.  The price, accordingly, is higher too.
Title: Re: Dual Channel Analysis Help
Post by: Jay Barracato on May 02, 2015, 02:20:03 AM
I hate the idea of having to do a show without smaart these days.

My total initial investment (computer, mics, interface box, and program) was about $2000 and I have used it for well over 500 shows over 5+ years.

So at this point I figure my cost is under $4 per show.

About the same as gaff tape and less than batteries.

Sent from my DROID RAZR HD using Tapatalk

Title: Re: Dual Channel Analysis Help
Post by: Lyle Williams on May 02, 2015, 04:37:46 AM
My lounge-level per-show economics are quite different.  :-)
Title: Re: Dual Channel Analysis Help
Post by: Tim McCulloch on May 02, 2015, 12:57:31 PM
My lounge-level per-show economics are quite different.  :-)

Jay is typically working venues <400 capacity but doing so for acts that want to be well presented to their audiences. 

If you already own a Win or Mac lappie and have a working audio interface with 2 or more inputs and outputs, all you need is the software and measurement microphone.  Oh, and lots of time to make invalid measurements and to listen to the results of acting upon them.  I made hundreds that were varying degrees of bogus *after* my first SMAART class, but then things started getting better as I practiced more.

It's worth it, Lyle.
Title: Re: Dual Channel Analysis Help
Post by: Ivan Beaver on May 02, 2015, 02:03:16 PM
Just as a friendly reminder-there are TWO aspects of system alignment.

The first and easiest is the software-knowing how to get around on it and so forth.

The second and much HARDER, is determining what the software is showing, and knowing what to do about it.

None of the programs tell you WHAT to do-they only show you the RESULT of your actions.  Just like modeling programs.

Let's say you have a dip in the response somewhere around crossover.  What do you do?  What could it be?

It could be a simple reflection in the measurement-so you simply ignore it-there is little you can do.

It could be signal misalignment time wise between the two freq bands.  Wat does your individual phase responses look like?

It could be something a little eq could fix. or not.

It could be that you don't have the crossover freq close enough to account for the freq response of the individual drivers.  OR it could be that they are to close and the response of one driver is cancelling the other.  Maybe some out of band eq could work better.

And ALWAYS remember to measure in more than 1 location.  You can get "hung up" on trying to make it perfect for one position, while making it WORSE for everybody else.

The one thing to remember is-don't go out and buy a measurement "kit", take a class or two and then think you are an expert and will get great results.

Some of us have been doing this a long time-and we STILL learn new things all the time.

Sometimes it can be frustrating.

BUT, with all that said-you WILL learn a lot more about a lot of things when you start to measure properly. :)