Tune your system the way live pro sound people do for cheap

I not denying that one should treat the room first, that is absolutely the correct procedure, what bugs me is people who refuse to measure, and insist that no tone controls are better, and do their EQing by switching out expensive speakers, turntables, amp, etc. Some knowledge of the way professionals proceed would break a lot of pointless log jams in the home audio hobby IMO.

I've never met anybody like that, but that might bug me a bit, too...however, if that's their idea of an enjoyable hobby it doesn't effect me very much at all.

je
 
I not denying that one should treat the room first, that is absolutely the correct procedure, what bugs me is people who refuse to measure, and insist that no tone controls are better, and do their EQing by switching out expensive speakers, turntables, amp, etc. Some knowledge of the way professionals proceed would break a lot of pointless log jams in the home audio hobby IMO.

I agree but its too late. I have a couple friends that are pro sound guys and they make more sense than many home guys I know. But I get annoyed with the "room ideas". The problem I have is I have lived and worked with the rooms I have. I have owned some very expensive room treatment material and found no advantage to it. I do think that some rooms sound better simply due to dimensions. But I sit very close (max 8ft) with every set up.

The point I like about having control over adjustment levels is they are usualy needed. I got into trouble on another thread with my vote in favor of the adustablity of active crossovers but thats life.


marc mc
 
Just saw this thread for the first time today. I used a modded Behringer DEQ2496 today to AutoEQ/Room Correct two sets of amps and speakers running off the same analog front end. Certainly agree with barredowl's on room treatment and EQing.

Wouldn't using two sets of full-range speakers in the same room cause enough comb filtering/cancellation that the Auto EQ function changes pretty significantly with any movement in the mic's location? Do you tend to sit in exactly the same location every time you listen to music on that system?

je
 
Thread moved, welcome listening space sub forum readers. I welcome any comments relating measuring rooms to treating rooms.
 
Is this essentially what the room correction/dynamic eq systems do in modern HT receivers? I have an Onkyo sr-606 with Audyssey EQ and I've been less impressed with what it does with Surround sound set up (it's intended purpose) and more impressed with it's ability to improve the 2-channel listening experience. Especially when integrating a sub. Sometimes I wonder why this technology doesn't seem to exist with modern stereo receivers.
 
Sorry if the answer to this question is really obvious, but wouldn't you want to measure your speakers' performance first and then measure the room? Someone earlier in the thread mentioned testing your speakers outside. How would you go about that? And then would you just subtract your speakers' known performance from the RTA reading to get only the performance of your room? Sorry, this is a pretty new topic to me and I'm a little confused...
 
Sorry if the answer to this question is really obvious, but wouldn't you want to measure your speakers' performance first and then measure the room? Someone earlier in the thread mentioned testing your speakers outside. How would you go about that? And then would you just subtract your speakers' known performance from the RTA reading to get only the performance of your room? Sorry, this is a pretty new topic to me and I'm a little confused...

This is one of the most sensible and valid inquiries Ive seen on this thread......I gave a detailed insight on how Professionals Tune their sound systems, since thats what I do for a living.......however the thread is still going, which is amazing so obviously the interest is there.

First question....Yes you do want to measure the speakers performance, you want to know what they are doing so you can then understand the effect they are having on the room.......IE; is it the room or the speakers, and that is a very important factor...
You could test the speakers outside, and reason for that is to eliminate reflections, like a basic anechoic chamber, but to really look at what speakers are doing you need more than an RTA, you need to look at phase as well as response.....
With the program I use, I can look at what the speakers are doing by using whats called a transfer function. We use Pink noise which is fed to the system and played through the speakers....The program has a sound card which has the analyzer mic which listens to the speakers, and the other channel listens to the noise going into the system, its quite involved but very basically I use a function in there to listen to both sources, which O can then line up with a snapshot if time, with a few settings (coherency and magnitude threshold), we can almost eliminate the room form the readings so we can see what the system is doing....
Because we use active sound systems with subs on the ground, and Mid high cabinets flown in the air nearly 30ft above the subs, we have to use time to line the phase between the cabinets on the ground and in the air.....
We also do this with the smaller "fill" speakers which we put along the front of the stage........
Back into your listening room....most people probably have passive systems so theres not much you can really do except use EQ....
I DO NOT use an RTA to tune my systems. I use my ears, and that is very important.... I used to use an RTA to help me ID frequencies, but Im a musician and I have 25 years of sound engineering, so I hardly ever look at the RTA unless Im lazy.....I like to use the spectrograph, I find them great because you never miss anything, it stays on the screen long enough for you to think about what is happening.
What you were heading towards in your post was pretty much on the money, and that is what the transfer function does, you can see what the speakers are doing and you can also tell if it is a reflection in the room......

One thing to consider, is you cannot fix a room with EQ, it is possible to greatly increase the performance of you speakers in a room, but one needs to remember, when you are taking chunks of EQ out, you are removing part of the music, so it needs to be done carefully......
I would say an average listening space is a lot better acoustically than a 12,000 seat arena, so you are already most of the way there.....

Heres a picture of my computer with SIA Smaart live 5 on it (dedicated computer) when I was phase aligning my L'acoustic SB115 subs to my JBL4410A.....
Theres two windows, the top one is the phase window, and the bottom one is the response window with the coherency trace.......
Thats a whole different topic.....
My analyser mic is a B&K4007, they are very fragile and very expensive....
img0371kk.jpg
 
Thanks for your reply kevzep! It's obvious that you really know what you're talking about (and it's probably obvious that I don't...). Do you have any suggestions for people like me who don't have an RTA but have good ears? (I'm also a musician, and I have absolute pitch which helps in identifying frequencies--I just look up the frequency corresponding to the note and I'm pretty much there)
Personally, my goal is to get the best response by passive means like speaker placement and maybe some acoustic treatments. I'm not really interested in using EQ unless there is something completely out of whack that can't be fixed otherwise. I don't need perfection, just the best I can get on a tight budget. With that in mind, what would you say would be the most important thing(s) (in general) to take care of? Maybe a step by step plan... if that won't divulge to many of your hard-earned professional secrets :D

On a related note, it seems as if you don't think an RTA is essential to tune a room; am I right? What tools, if any, are essential in your opinion for optimizing the average Joe's room?
 
Thanks for your reply kevzep! It's obvious that you really know what you're talking about (and it's probably obvious that I don't...). Do you have any suggestions for people like me who don't have an RTA but have good ears? (I'm also a musician, and I have absolute pitch which helps in identifying frequencies--I just look up the frequency corresponding to the note and I'm pretty much there)
Personally, my goal is to get the best response by passive means like speaker placement and maybe some acoustic treatments. I'm not really interested in using EQ unless there is something completely out of whack that can't be fixed otherwise. I don't need perfection, just the best I can get on a tight budget. With that in mind, what would you say would be the most important thing(s) (in general) to take care of? Maybe a step by step plan... if that won't divulge to many of your hard-earned professional secrets :D

On a related note, it seems as if you don't think an RTA is essential to tune a room; am I right? What tools, if any, are essential in your opinion for optimizing the average Joe's room?

I think the best thing to do, is to do exactly as you suggest, treat the room......I dont think it takes much, carpet floors, have rugs and mats, hang mats or rugs on the walls and make sure they are free hanging.....never have a wooden polished floor, have soft furniture, my room is sort of an L shape carpeted, I have drapes and net curtains, it works well.....its not a huge area, if it was bigger with higher ceilings I might have to treat the walls, but I dont find it to be a problem the way it is.......

If you have a good amplifier and decent speakers I think you cant go wrong.....I went the sub route because I like a lot of weight in my music, I mix live all the time and Im kind of used to it sounding this way, live for the want of a better expression.......you know bass guitar sounding like a bass guitar, it just doesnt work for me having kick drums and bass guitars through 8inch speakers........but thats personal preference.......

If you are musical and looks like you are, you will be able to tell immediately if the room has reflections or resonances, and thats when you start treating the room...I think you can even buy acoustic foam for walls and the likes fairly easily these days......but I believe if you have the system you like and you know, if the room is a problem you will know.......

I had my analyzing equipment at home working out what the system was doing and how best to integrate the subs with the 4410A's......
Once I know what the speakers do, thats my reference, I dont need an RTA, I can hear what I want to do with my EQ (BSS parametric FCS926, FPC900i, FPC900r) it has a remote which follows me round and sits nest to me on the couch, as it is right now while Im typing......
Below is the Equalizer
p1050826u.jpg

and the interface
p1050828.jpg

and the remote
p1050825e.jpg

The reason I have a EQ is not to correct the room, I have it because everything is mixed and mastered differently, and I like to massage the sound a bit with the EQ to get it the way I like it, and Im not talking about using a lot of EQ, just little bits....it changes depending on whether its cold or hot and humid, and the type of music Im listening to......one minute its BB King live at the Regal, then its Stampede by the Doobie Brothers, or Guess Who.....and all this stuff needs a tweak in the right place.....to do that I dont need an RTA, HOWEVER, if you arent experienced at listening and converting what you are hearing into EQ language (knowing what to apply or remove and how much) then an RTA could be useful, and to be honest, the ones you get as iPhone apps are pretty good actually, I have a couple but never use them.....but theres no harm and certainly no rule that says they dont work........and not to use them....
For someone like yourself an RTA would teach you iso frequency language quickly because you are musical....but seem as you arent EQing you probably dont really need one....
Ive been talking about this topic in another thread today as well, and even posted the same pictures.....oh well, at least its all covered.....
I been through a lot of listening to albums while typing today!!!

I dont really have any secrets, the gift is in the ability to translate what you hear, to what to do.....thats where I have the talent, when I started doing sound I always impressed guys who had been doing it far far longer than I had, so I got told I had an unusual talent for system tuning, and consequently it also worked well for my audio engineering....
It probably seems ridiculous for me to sit here with a parametric equalizing my music......but you know, I enjoy music more when Im getting the best out of the system and the recording........
I always when using eq, reference what Im doing with what it sounds like with the EQ flat......this is essential to monitor what improvement if any is being made, and that is where I see a lot of people go wrong........

I hope this answers your questions.......
 
Hi kevzep;

Will you explain the screen shot in post 147 a bit? I have not used SMAART and am trying to understand exactly what I'm seeing. In the top half of the screen is the yellow trace the sub run from the bottom up to about 200hz and the blue the 4410's from the top down to about 60? Can you manipulate the receive delay to unwrap the phase or is that the preferred display?

On the lower half of the screen what is shown in the 200 Hz and down range? Coherant summation? Why are the traces at about zero above that? It's not the noise floor I suppose as the traces and scale go negative as well? Is that just a set reference level?

Are these tests sampled with the mic at a boundary?

Thank you in advance,
Barry.
 
Hi kevzep;

Will you explain the screen shot in post 147 a bit? I have not used SMAART and am trying to understand exactly what I'm seeing. In the top half of the screen is the yellow trace the sub run from the bottom up to about 200hz and the blue the 4410's from the top down to about 60? Can you manipulate the receive delay to unwrap the phase or is that the preferred display?

On the lower half of the screen what is shown in the 200 Hz and down range? Coherant summation? Why are the traces at about zero above that? It's not the noise floor I suppose as the traces and scale go negative as well? Is that just a set reference level?

Are these tests sampled with the mic at a boundary?

Thank you in advance,
Barry.

Sorry for the slow reply, this part of the forum is tucked away and I only come in here every few days.....

Welcome to AK, best forum on the internet........:thmbsp:

Okay, one thing to realize about particularly this older version of Smaart, is that it works best outdoors, or in large arenas, using it in a lounge like I am can be a bit misleading if you dont know what you are looking for, because of the confined space creating early reflections, and some of the information which shows up isnt as accurate as the newer version 7 (will be getting a copy soon).....particularly in the coherency department......
But, if you use it all the time like I do, then you know what to believe and what not to believe......

The setup is this, Smaart is looking at two signals, one is a reference signal, which is directly from the source (pink noise generator), and then the microphone, which is positioned in this case at the listening position.....
Smaart looks at both signals, the dry signal, and the signal being picked up by the microphone, the response is the result of a comparison of the two signals so we can see what is actually coming from the system, rather than looking at all the sound being picked up by the mic including reflections and background noise, we use the transfer function to tune the system, we are not interested in what the room is doing when we tune the system, if we try to tune the system with the RTA, we could be looking at room nodes or nulls and trying to compensate these by compromising the performance of the system......after we have the system optimized, we can then look at the performance of the system with regards to the room, but in the case say of looking at the phase relationship of the subs in the system, we dont want the room screwing up the readings.....

The object here was to make sure the sub was showing a compatible phase correlation to the low end of the 4410A's.....(moot now, because I have my JBL L5's back in service, so I went through the whole process again)

What you are seeing in the top window, is indeed the phase trace of the SB-115 sub. (I think that picture might have been before I moved the crossover point down). In this case you can see the 0 degrees is in the middle and it goes to 180 degrees either side, so of course as the frequency goes higher the phase shifts, this is a typical trend for a driver of this size producing these frequencies....
When you see a wrap, its showing 360 degrees phase shift....it wraps and continues on from the opposite side of the display....
You can change the display to unwrap the trace, but we use this as the default display, this is more useful for what we are doing and less likely to give the "wrong impression"......
So this trace is whats active currently.........I have the 4410A's off at this point.....

The blue trace is the 4410A phase trace which I captured as a snapshot. The reason I am looking at this, is to see how the sub phase trace on its own, lines up with the lower range of the 4410A. As you can see, in the area of its active response it lines up, especially at the crossover point, so its all good....If it doesnt line up, I would have to use some delay to effectively push the sub into a position where it is lined up......
Some care is needed because it is easy to apply too much delay and think you have it lined up, but in actual fact, you have it lined up a whole wavelength behind where it should be.......you can tell by the amount of wraps, which will basically double over the same frequency range as the captured trace....

On the lower window, the yellow trace is the frequency response on the SB-115 sub, and the blue trace is the captured frequency response of the 4410A.
When I turn the 4410A on I can then see how the response is affected at the crossover point.....
When both speakers are going at the same time it becomes all too obvious if you have got your alignment wrong.....or right for that matter.....
So you see why we dont want the room to interfere with the readings......
The red trace, is the coherency trace, this is supposed to tell us if what we are seeing is actually coming from the system, or whether it is a reflection of some other interference......
The coherency in this version of smaart is a bit rudimentary and cant always be taken at face value......
For example, it says there is something weird happening at 250hz, but I know from experience using this version, and my ears, that its just an anomaly in the coherency calculation within smaart....could have been a random reflection off the wall behind the mic, although in this case unlikely..
The level is at zero when the two signals are at the same level, I have turned the sub up a bit from the trace I took of the 4410A because of the lack of sensitivity to the low frequencies, the readings tend to be more accurate and defined for the low frequencies with the system producing a bit more SPL.......

The microphone was sitting pretty much where I took the photo from....
The B&K4007, very important to use a good mic, I think these are upwards of $2500US.....but if you want high accuracy......

I hope it all makes sense Barry, and again welcome to Audio Karma!!!
 
Thanks for the explanation, and the welcome.

I use the TEF measurement system and it is the only one that I am intimately familiar with. I am interested in SMAART in part because a friend of mine has it and could use some help with it. I know all these systems have their strengths and weaknesses so learning any other system will be of value to me as well.

Thanks again,
Barry.
 
Thanks for the explanation, and the welcome.

I use the TEF measurement system and it is the only one that I am intimately familiar with. I am interested in SMAART in part because a friend of mine has it and could use some help with it. I know all these systems have their strengths and weaknesses so learning any other system will be of value to me as well.

Thanks again,
Barry.

You are most welcome......
The latest version of smaart V7, is very good and many improvements have been made, the only down side is the price really......
The best part is its available for Mac OS now.......Im not an advocate for PC's....
http://www.rationalacoustics.com/pages/Smaart_Landing_Page
 
An amazing thread to say the least. Very informative! I too will play around with the theory and some of the equipment /programs mentioned. If for nothing else, the experience. Thanks to all who contributed to this excellent read. Two thumbs up! :thmbsp: :thmbsp:
 
When I read the title of this thread, I was filled with horror. After reading through this entire thread, I am more horrified than I thought I would be. I have been tuning systems in movie theaters, dubbing stages, churches, and high end audio and home theaters for 20 years, and the way the original poster describes tuning a system for a room is not the way the pro's do it.

First, EQ alone cannot do the job, it requires several acoustical tools. EQ does great in the frequency domain, but fails miserably in the time domain. My practice is to always measure first, move seats or subs, measure again, add acoustical material, measure again, and the use EQ to tweak the final response. Every time I change something, I measure to see its effects.

Tuning a system(you don't tune rooms) is not a cheap affair if it is done correctly. In order to do it correctly, you need the right tools. A iphone app. and the iphone microphone does not have the resolution or accuracy to effectively identify room issues. Online software(with the exception of REW) also does not have the resolution to proper identify room problems. Also the sound card included on most PC's are not very good, even when the software is optimized for its drawbacks. You need a high quality soundcard, a lab grade calibrated microphone, and some high resolution software to get the job done. I use between 2 and 8 DPA lab grade microphones, a multiplexing system, and the MLSSA measuring system. I also use Audyssey XT32 Multi-EQ Pro on my home systems.

There are several ways to measure a room, and it depends on whether you are measuring for a single place, or averaging for several places in the room. There is only one ideal spot where all of the output converges at the ears in the time domain. I use this place as my target area to tweak, and try to get as many seats as possible close to that reference spot. The worst problems you find in small rooms are room modes(resonances) at bass frequencies. The modes are loudest in corners, and close to the walls. The goal is to neutralize the acoustical abnormalities of the room, not to make it dead. Dead rooms do not sound very good, and they require huge increases in the power of the system. You only want to lower or remove resonances in the room, not totally remove the rooms influence.

When fixing acoustical issues in rooms, it is best to divide the measurements into two frequency domains. One for the upper and mid frequencies, and another for low frequencies. I use 1/3 octave resolution for the mid and upper frequencies, and 1/10, 1/12 and even 1/20 octave resolution for bass frequencies. You also must take into consideration modal ringing, reverb, and impulse response in your measurements. You may see a close to flat response on the RTA, but some frequencies may ring longer than others so it is helpful to get a waterfall plot along with a raw frequency measurement.

I find sine wave sweeps much more helpful at identifying acoustical problems than pink noise.

Once you measure, you have to decide which acoustical tools you need to fix the problem. You must have knowledge of how to read an RTA, as it is not as straight forward as it seems. The most common misused tool is absorption. One of the most un-used tools is diffusion. Both should be used together along with EQ to get the system response on target.

When one has done system tuning as long as I have, you know that acoustical problems are very complex, and cheap EQ cannot fix it.
 
. The worst problems you find in small rooms are room modes(resonances) at bass frequencies. The modes are loudest in corners, and close to the walls. The goal is to neutralize the acoustical abnormalities of the room, not to make it dead...

Nice post, please tell me the best practice to help a small room with regard to resonance? I'm loosing some bass in my listening room. Oh and I don't have a EQ.

Cheers,

Bob
 
When I read the title of this thread, I was filled with horror. After reading through this entire thread, I am more horrified than I thought I would be. I have been tuning systems in movie theaters, dubbing stages, churches, and high end audio and home theaters for 20 years, and the way the original poster describes tuning a system for a room is not the way the pro's do it.

First, EQ alone cannot do the job, it requires several acoustical tools. EQ does great in the frequency domain, but fails miserably in the time domain. My practice is to always measure first, move seats or subs, measure again, add acoustical material, measure again, and the use EQ to tweak the final response. Every time I change something, I measure to see its effects.

Tuning a system(you don't tune rooms) is not a cheap affair if it is done correctly. In order to do it correctly, you need the right tools. A iphone app. and the iphone microphone does not have the resolution or accuracy to effectively identify room issues. Online software(with the exception of REW) also does not have the resolution to proper identify room problems. Also the sound card included on most PC's are not very good, even when the software is optimized for its drawbacks. You need a high quality soundcard, a lab grade calibrated microphone, and some high resolution software to get the job done. I use between 2 and 8 DPA lab grade microphones, a multiplexing system, and the MLSSA measuring system. I also use Audyssey XT32 Multi-EQ Pro on my home systems.

There are several ways to measure a room, and it depends on whether you are measuring for a single place, or averaging for several places in the room. There is only one ideal spot where all of the output converges at the ears in the time domain. I use this place as my target area to tweak, and try to get as many seats as possible close to that reference spot. The worst problems you find in small rooms are room modes(resonances) at bass frequencies. The modes are loudest in corners, and close to the walls. The goal is to neutralize the acoustical abnormalities of the room, not to make it dead. Dead rooms do not sound very good, and they require huge increases in the power of the system. You only want to lower or remove resonances in the room, not totally remove the rooms influence.

When fixing acoustical issues in rooms, it is best to divide the measurements into two frequency domains. One for the upper and mid frequencies, and another for low frequencies. I use 1/3 octave resolution for the mid and upper frequencies, and 1/10, 1/12 and even 1/20 octave resolution for bass frequencies. You also must take into consideration modal ringing, reverb, and impulse response in your measurements. You may see a close to flat response on the RTA, but some frequencies may ring longer than others so it is helpful to get a waterfall plot along with a raw frequency measurement.

I find sine wave sweeps much more helpful at identifying acoustical problems than pink noise.

Once you measure, you have to decide which acoustical tools you need to fix the problem. You must have knowledge of how to read an RTA, as it is not as straight forward as it seems. The most common misused tool is absorption. One of the most un-used tools is diffusion. Both should be used together along with EQ to get the system response on target.

When one has done system tuning as long as I have, you know that acoustical problems are very complex, and cheap EQ cannot fix it.

I agree with your post, but there is more than one way to skin a cat....as they say....

I work in the live sound reinforcement industry and have done for about 22 years as an engineer, and system tech, I gave an account of how many accomplished system engineers tune systems......

Im hoping you are horrified at the OP's posts and not mine, I think there are many similarities in our (yourself and myself) understanding ......
But we use different tools and have different methods, and there are very valid reasons for this....... I respect yours, and I hope you respect mine.....
I thought your post was very good.....I appreciate your taking the time to share.
I think its good to see other methods at work.....

I agree EQ cannot do the job alone, but in the case of a touring live sound reinforcement system, EQ and Array prediction and steering is all we have, so we are up against it from the start......
Where you point those cabinets is more important than ever....
So its a compromise, the first thing for anyone in my position is that you cannot EQ your way out of it.......people try, and it always ends in what I call a "sound accident".

Must be wonderful to be able to change the acoustics of a room to make improvements, I have never had that luxury.......I wish I put some diffusers in our local 12,000 seat arena here, it would make the concert going experience much better than it is now....

I and most live guys, use Smaart Live, which is up to version 7, its very versatile and quick to use.......I assume you may have checked it out, it possible not the right tool for the way you like to work.....but none the less it is an extremely good professional tool
http://www.rationalacoustics.com/pag...t_Landing_Page

I like to use pink noise, purely because with the time constraints we are up against, we just wouldnt have the time to do sine sweeps......
Also there is other work happening as well putting the show up, lighting, video, backline etc....so I can use pink noise in bursts which doesnt annoy people too much, and with the impulse measurements for time aligning it uses pink noise......

It is important to understand what you are looking at on an RTA, spectrograph, impulse, transfer functions......and there are many people out there fooling around with this stuff that dont understand it........I use the transfer function to tune the system and then after the system is tuned, I will then have a look at the RTA......and make some minor adjustments....

Yes, acoustical problems are very complicated, but understanding the equipment you use, providing you are using good equipment, how to implement it, and the limitations of the physics involved will yield some great results....
 
I agree with your post, but there is more than one way to skin a cat....as they say....

You are certainly correct. Especially when dealing with a house cat as opposed to a Lion.

I work in the live sound reinforcement industry and have done for about 22 years as an engineer, and system tech, I gave an account of how many accomplished system engineers tune systems......

I have done just about everything sound related over my 25 years of recording and mixing. I do live sound every Sunday at my church(which includes lights and a huge projection system), was the lead house mixer for the Paramount Theater in Oakland, and the Greek Theater in Los Angeles. I have done more live shows than I can remember. Currently I work for a major Hollywood studio mixing soundtracks for DVD and Bluray. I have recorded hundreds of film scores and audio tracks over the years.

Im hoping you are horrified at the OP's posts and not mine, I think there are many similarities in our (yourself and myself) understanding ......
But we use different tools and have different methods, and there are very valid reasons for this....... I respect yours, and I hope you respect mine.....
I thought your post was very good.....I appreciate your taking the time to share.
I think its good to see other methods at work.....

Actually, I agreed with your post. An arena, and our rooms at home have very different acoustical properties, so each would naturally have a different methods and tools to tune a system.

I agree EQ cannot do the job alone, but in the case of a touring live sound reinforcement system, EQ and Array prediction and steering is all we have, so we are up against it from the start......
Where you point those cabinets is more important than ever....
So its a compromise, the first thing for anyone in my position is that you cannot EQ your way out of it.......people try, and it always ends in what I call a "sound accident".

Tuning a line array in a arena or concert hall is quite different than tuning a home theater or audio system in a average size listening room at home. I have done both, and you really have to have a different mindset and approach for each.

Must be wonderful to be able to change the acoustics of a room to make improvements, I have never had that luxury.......I wish I put some diffusers in our local 12,000 seat arena here, it would make the concert going experience much better than it is now....

In the home, you have a far smaller space with speakers a lot closer to walls than in a arena. In order to get good sound in smaller rooms, you have to use tools that changes the way the system interacts with the room. IMO, a line array flown in space is far easier to contend with than a home theater or audio system placed in a smaller room. Aside from reverberation time, there is far less to worry about than in the home.

I and most live guys, use Smaart Live, which is up to version 7, its very versatile and quick to use.......I assume you may have checked it out, it possible not the right tool for the way you like to work.....but none the less it is an extremely good professional tool
http://www.rationalacoustics.com/pag...t_Landing_Page

I am very familiar Smaart Live. Great software package for aligning a system in a large space. I would not use it on home theaters or audio systems, but would and have for P.A. systems.

I like to use pink noise, purely because with the time constraints we are up against, we just wouldnt have the time to do sine sweeps......
Also there is other work happening as well putting the show up, lighting, video, backline etc....so I can use pink noise in bursts which doesnt annoy people too much, and with the impulse measurements for time aligning it uses pink noise......

Sine wave sweeps would not be appropriate for a touring system. The reverberation qualities of a large room would skew the measurement results. You guys do have time restraints during set up that don't exist when doing home theaters and audio systems.

It is important to understand what you are looking at on an RTA, spectrograph, impulse, transfer functions......and there are many people out there fooling around with this stuff that dont understand it........I use the transfer function to tune the system and then after the system is tuned, I will then have a look at the RTA......and make some minor adjustments....

This is why you cannot tune your system like the pro's do for cheap. If you cannot read the cheap RTA accurately(like a cheap one will be accurate), then your EQ will not be effective, or will likely make things worse.

Yes, acoustical problems are very complicated, but understanding the equipment you use, providing you are using good equipment, how to implement it, and the limitations of the physics involved will yield some great results....

I absolutely agree. It is not as easy as the OP makes it, but thanks to technology it is a lot easier than it use to be.
 
Nice post, please tell me the best practice to help a small room with regard to resonance? I'm loosing some bass in my listening room. Oh and I don't have a EQ.

Cheers,

Bob

Is your system a 2.0 or 5.1 system?

In small rooms, I recommend placing the subwoofer where the frequency response is the smoothest - and then adding a room curve to the equation. The place where the sub has the flattest frequency response is in the front center wall area. This position(aside from the center of the room) excites fewer room modes and nodes, but lacks deep bass support that a corner location provides. So if you sub is up to the task, I would add some equalization to support the roll off point of the subwoofer - below 40hz or so. Bass traps are also helpful to tame extra energy above 80hz, depending on the asorption material of the trap itself.

You really need some parametric EQ to deal with modes below 80hz, which are problem frequencies in small rooms.
 
I not denying that one should treat the room first, that is absolutely the correct procedure, what bugs me is people who refuse to measure, and insist that no tone controls are better, and do their EQing by switching out expensive speakers, turntables, amp, etc. Some knowledge of the way professionals proceed would break a lot of pointless log jams in the home audio hobby IMO.

But if it wasn't for people doing just that, I and a lot of other people in this hobby would not have the benefit of purchasing said cast offs.

Take care,

Rob
 
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