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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 => LAB Lounge => Topic started by: Bob Kidd on May 18, 2014, 09:28:37 PM

Title: Pink Noise
Post by: Bob Kidd on May 18, 2014, 09:28:37 PM
Looking at using pink noise to flatten EQ response in room. I currently have PA driverack and could use the RTA to accomplish this or do you feel it would just be better to use ear and adjust? I find RTA to be useless. MHO. Would feed pink noise in my Sound Craft compact. Would this acheive what Im looking to do? Have little luck in getting someone to come in that has SMART system to tune system so this would be my only alternative at this point. Thanks for help
Title: Re: Pink Noise
Post by: David Parker on May 18, 2014, 09:30:42 PM
Looking at using pink noise to flatten EQ response in room. I currently have PA driverack and could use the RTA to accomplish this. Would feed pink noise in my Sound Craft compact. Would this acheive what Im looking to do? Have little luck in getting someone to come in that has SMART system to tune system so this would be my only alternative at this point. Thanks for help
the driverack has a pink noise generator
Title: Re: Pink Noise
Post by: Bob Kidd on May 18, 2014, 09:33:15 PM
the driverack has a pink noise generator

True, have not had a whole lot of sleep the past few days. I guess what Im looking at is use PA with pink and RTA or use Pink in Sound Craft and adjust by ear? Thanks
Title: Re: Pink Noise
Post by: Paul G. OBrien on May 18, 2014, 10:35:09 PM
Looking at using pink noise to flatten EQ response in room.
Unless you like to piss off all the patrons in the room you're about to perform in don't go there. Instead use pink noise and the RTA or Smaart to flatten response of the speaker system in a non reverbant environment(outdoors) and save this as your baseline. Then when you setup indoors you know any non linearities(booming bass, piercing highs) are caused by the room and should be fixed with speaker positioning and room treatment first(where possible) or minimized with EQ second.

I find RTA to be useless.
That's because it's like trying to illuminate a large room with a flashlight, in order to see the whole room at once you need some way of taking a snapshot at each flashlight position and pasting them all together in a big collage.
Title: Re: Pink Noise
Post by: Bob Kidd on May 18, 2014, 10:44:07 PM
Unless you like to piss off all the patrons in the room you're about to perform in don't go there. Instead use pink noise and the RTA or Smaart to flatten response of the speaker system in a non reverbant environment(outdoors) and save this as your baseline. Then when you setup indoors you know any non linearities(booming bass, piercing highs) are caused by the room and should be fixed with speaker positioning and room treatment first(where possible) or minimized with EQ second.
 That's because it's like trying to illuminate a large room with a flashlight, in order to see the whole room at once you need some way of taking a snapshot at each flashlight position and pasting them all together in a big collage.

You are correct that would uspet some customers. I was going to perform in morning before venue open. System usually stays in this venue and was trying to avoid taking out to run test but this would give me a good baseline. Thanks for your help
Title: Re: Pink Noise
Post by: David Parker on May 18, 2014, 11:23:02 PM
You are correct that would uspet some customers. I was going to perform in morning before venue open. System usually stays in this venue and was trying to avoid taking out to run test but this would give me a good baseline. Thanks for your help
I pink all my speakers at home, outside, for a baseline, save the settings. I use DR260, it works really well with laptop. I eq to taste live on top of the baseline. The RTA just gets me in the ball park. Never use it at the venue.
Title: Re: Pink Noise
Post by: Jerome Malsack on May 19, 2014, 08:17:00 AM
I have run the pink on my system at home and used True Audio RTA to view the results.  Then when satisfied I pull up my Itouch and use a cheap RTA app loaded there to review the results also.   

When at the location and playing music I can review the Itouch RTA to ensure the room sound and adjust EQ as needed. 

When doing the RTA with True Audio.  I have screen shots of the results of each driver from the speakers to allow me to see the differences and to help when confirming a loss. 
Title: Re: Pink Noise
Post by: Steve Oldridge on May 19, 2014, 10:25:27 AM
I pink all my speakers at home, outside, for a baseline, save the settings. I use DR260, it works really well with laptop. I eq to taste live on top of the baseline. The RTA just gets me in the ball park. Never use it at the venue.

Same here (DRPA).. and trying to convince current band leader (and PA owner) that he should do the same and not RTA the room before every gig.  I took my PA out last week (for one gig) with this band. First use in over a year.  Yes, the bass was a tad boomy - large warehouse-like room - that was easily tamed by judicious EQ. Rest was crystal clear, unlike our normal PA which sounds like it's being choked and not "breathing".   Yes, some rooms are ugly, but most consoles I have used can adequately compensate from baseline RTA.
Title: Re: Pink Noise
Post by: dave briar on May 19, 2014, 12:15:27 PM
Looking at using pink noise to flatten EQ response in room. I currently have PA driverack and could use the RTA to accomplish this or do you feel it would just be better to use ear and adjust? I find RTA to be useless. MHO. Would feed pink noise in my Sound Craft compact. Would this acheive what Im looking to do? Have little luck in getting someone to come in that has SMART system to tune system so this would be my only alternative at this point. Thanks for help
I agree with others that pinking a room full of patrons is a REAL bad idea.  That said, it did  prove useful at a gig last Saturday.  We finished set up in a public-facility ballroom at noon for a 7:00PM show so I had plenty of time with only ~20 or so vendor etc folks around finishing their setup.  I'm sure they didn't really appreciate it but couldn't really complain too much either. 

I fed pink from StudioSix AudioTools on my phone through the mixer and used the built in mic on my iPad to view the FFT display.  Not ideal for sure but more than workable and did allow me to even out some problem frequencies.  I also walked around the venue some to check for variations which I found but nothing that ran against the basic EQ I did from the original front-and-center position.  The event went very well and the music and announcements (this was a high-visibility fund raiser) were clear everywhere so at least I don't think I did any harm <wink>!
Title: Re: Pink Noise
Post by: g'bye, Dick Rees on May 19, 2014, 12:29:18 PM
Looking at using pink noise to flatten EQ response in room. I currently have PA driverack and could use the RTA to accomplish this or do you feel it would just be better to use ear and adjust? I find RTA to be useless. MHO. Would feed pink noise in my Sound Craft compact. Would this acheive what Im looking to do? Have little luck in getting someone to come in that has SMART system to tune system so this would be my only alternative at this point. Thanks for help

I'm often old school/low tech on this...setting up an SM58 out in the room about 7-8 feet in the air pointing directly up.  I then go through the spectrum from LF to HF with a GEQ boosting each band in turn to identify any problem areas/room modes.  For precision (with time) I'll then use the GEQ results as a starting point to go through and set more precise, narroer PEQ filters.

This takes as much or less time as any other method and does not require any noise or even much "feedback" as one can hear the onset of any ringing at a very low level.  Lather, rinse and repeat to taste.
Title: Re: Pink Noise
Post by: David Parker on May 19, 2014, 12:33:18 PM
I'm often old school/low tech on this...setting up an SM58 out in the room about 7-8 feet in the air pointing directly up.  I then go through the spectrum from LF to HF with a GEQ boosting each band in turn to identify any problem areas/room modes.  For precision (with time) I'll then use the GEQ results as a starting point to go through and set more precise, narroer PEQ filters.

This takes as much or less time as any other method and does not require any noise or even much "feedback" as one can hear the onset of any ringing at a very low level.  Lather, rinse and repeat to taste.
back before I got my first rta, long before digital processors were popular, I'd set up a '57 in the room and do the same thing, It was amazing how much I could tell about the room by raising each frequency until it started feeding back. After doing that, anything on a '57 or '58 sounded really good!
Title: Re: Pink Noise
Post by: Bob Kidd on May 19, 2014, 12:44:45 PM
I agree with others that pinking a room full of patrons is a REAL bad idea.  That said, it did  prove useful at a gig last Saturday.  We finished set up in a public-facility ballroom at noon for a 7:00PM show so I had plenty of time with only ~20 or so vendor etc folks around finishing their setup.  I'm sure they didn't really appreciate it but couldn't really complain too much either. 

I fed pink from StudioSix AudioTools on my phone through the mixer and used the built in mic on my iPad to view the FFT display.  Not ideal for sure but more than workable and did allow me to even out some problem frequencies.  I also walked around the venue some to check for variations which I found but nothing that ran against the basic EQ I did from the original front-and-center position.  The event went very well and the music and announcements (this was a high-visibility fund raiser) were clear everywhere so at least I don't think I did any harm <wink>!

That is what I'm going to do in this situation, use the FFT on my iPad and level out problem freq to get room tuned and a flat EQ for house. I do have tech coming up at some point with SMART.