[gkinberg]

Hello,

I am planning to treat my room with panels to tame some livelyness and first reflections.

It is probably obvious but it occurred to me that I should measure my room with a program such as Room EQ Wizzard or something equivalent before I acoustically treat it. If my room measures poorly will the program and its measurements guide me as to how to treat my room?

Thanks, Garth

[JohnR]

I don't have an answer but I think it's a fabulous question.

[bpape]

REW will not directly tell you what you need to do. It's simply a tool that will assist you in getting the best possible response from your setup based on tweaking speaker/sub/chair positions.  It will also show you the overall decay time in the room which can imply which is modal and not modal.  Lastly, it can help via impulse response show you where in time your reflections are coming from.

The data is all there - just a matter of understanding how to interpret it.

Bryan

[Levi]

I seek Brian on this one.

Once you have your measurements providing your equipment are properly calibrated.  You need to analyze the graphs which gives you hints what you need to do next.  Treat your room and measure it again to see if there are improvements.  It is trial and error type thing. 

[Ethan Winer]

If my room measures poorly will the program and its measurements guide me as to how to treat my room?

This is a common question, right up there with "Will a mode calculator tell me how to treat my room?" The answer to both is No. The main reasons to measure your room are:

1) To see how bad it really is. Most people used to seeing frequency response graphs for electronics and speakers have no idea how badly all rooms skew the response.

2) To see how much better the response and ringing became after adding treatment. Of course, the improvement from adding room treatment is always very obvious by ear.

I never suggest not measuring! Some people enjoy learning the theory behind room acoustics. But for those who just want a solution, measuring is not really needed. Regardless of what you measure, the basic solution will be the same anyway: corner bass traps plus absorbers at the side-wall and ceiling reflection points.

--Ethan

[Tyson]

Try HOLM Impulse - it's free and more comprehensive.  It will show you where your major nodes are.  There are 3 major dimensional nodes in every room - Front to Rear, Side to Side, and Floor to Ceiling.

The thing to be aware of - the side to side and front to rear bass nodes will change depending on your listening location.  These are iffy when it comes to correction.  However, there's also a floor to ceiling mode which will stay fairly consistent throughout the room, and that should definitely be attacked with EQ or a bass trap.

This is one reason people like Open Baffle subs so much - it acoustically deals with one of the room modes (side to side), leaving only the floor-ceiling and Front-Rear wall modes to deal with.  Floor-Ceiling can be dealt with via EQ or Bass traps, and so you are only left with a single troublesome node.  Still not perfect, but a lot better than three bad nodes!

[jtwrace]

Try HOLM Impulse - it's free and more comprehensive. 

and it doesn't crash all of a sudden.

This is one reason people like Open Baffle subs so much - it acoustically deals with one of the room modes

..and one of the reasons that a multiple sub (3 or more) approach works really well.

[Tyson]

One doesn't really preclude the other.  But yes, multiple subs are the way to go, if you can do it.  I like both methods because it deals with the problem in the acoustic realm, not in the electronic realm; that's always the way to go if you can.

[KJ]

I used REW when capturing measurements for treating my entire room quite successfully.  However, I needed the expertise of an "acoustician" to know how and where to treat specific frequency peaks and nulls.

Jeff Hedback might have some good insight.  I worked with him to treat my room and wanted to use REW since I had it on hand.  However, this might not have been his preferred tool of choice when importing the measurements.  I'm sure he and other acoustic experts can indicate the pros/cons of using this when importing the files into their tool sets.

[etcarroll]

Tyson - What mic did you use with HOLM product?

Try HOLM Impulse - it's free and more comprehensive.  It will show you where your major nodes are.  There are 3 major dimensional nodes in every room - Front to Rear, Side to Side, and Floor to Ceiling.

The thing to be aware of - the side to side and front to rear bass nodes will change depending on your listening location.  These are iffy when it comes to correction.  However, there's also a floor to ceiling mode which will stay fairly consistent throughout the room, and that should definitely be attacked with EQ or a bass trap.

This is one reason people like Open Baffle subs so much - it acoustically deals with one of the room modes (side to side), leaving only the floor-ceiling and Front-Rear wall modes to deal with.  Floor-Ceiling can be dealt with via EQ or Bass traps, and so you are only left with a single troublesome node.  Still not perfect, but a lot better than three bad nodes!

[Tyson]

Originally used a Behringer, calibrated from Cross-Spectrum but I could never get the calibration file to load up properly to HOLM.  So I sold it and got a "real" mic, the Earthworks M23, which is pretty much perfect out of the box (even though they provide a calibration file too - the correction is so minor as to be pointless).  Plus the M23 is phase and impulse perfect and the Behringer is not (and that cannot be addressed via calibration files).

[jtwrace]

Originally used a Behringer, calibrated from Cross-Spectrum but I could never get the calibration file to load up properly to HOLM. 

Strange.  I'm able to load my cross spectrum cal file with no issue into Holm.

Plus the M23 is phase and impulse perfect and the Behringer is not (and that cannot be addressed via calibration files).

You might be interested in this link especially the comments from Herb from Cross Spectrum.  http://www.hometheatershack.com/forums/spl-meters-mics-calibration-sound-cards/31380-ecm8000-phase-response.html

[gkinberg]

Thanks to everyone for all the input. I haven't even looked at REW yet so I don't know what is required but I don't have a "real" microphone. What I do have is the setup mic that came with my onkyo receiver. I know it is probably heresy but that is the microphone that I was planing on using initially. Depending on the results and if necessary, I might set up to a behringer or something. Good, bad or indeed, heresy?

Garth

[jtwrace]

Thanks to everyone for all the input. I haven't even looked at REW yet so I don't know what is required but I don't have a "real" microphone. What I do have is the setup mic that came with my onkyo receiver. I know it is probably heresy but that is the microphone that I was planing on using initially. Depending on the results and if necessary, I might set up to a behringer or something. Good, bad or indeed, heresy?

Garth

If you own a Radio Shack SPL Digital meter you can use that to start with.  They're really not bad.

http://www.realtraps.com/art_microphones.htm

Download from Home Theater Shack for the RS Meter http://www.hometheatershack.com/forums/downloads-area/19-downloads-page.html

[Ethan Winer]

I can't imagine why the phase response of a microphone matters when measuring a room.

--Ethan

[Tyson]

Oh, phase doesn't matter with room measurement.  Some people might question why the Earthworks is more expensive, and I was simply pointing out a couple of reasons why.

[Nyal Mellor]

This is a common question, right up there with "Will a mode calculator tell me how to treat my room?" The answer to both is No. The main reasons to measure your room are:

1) To see how bad it really is. Most people used to seeing frequency response graphs for electronics and speakers have no idea how badly all rooms skew the response.

2) To see how much better the response and ringing became after adding treatment. Of course, the improvement from adding room treatment is always very obvious by ear.

I never suggest not measuring! Some people enjoy learning the theory behind room acoustics. But for those who just want a solution, measuring is not really needed. Regardless of what you measure, the basic solution will be the same anyway: corner bass traps plus absorbers at the side-wall and ceiling reflection points.

--Ethan

What Ethan said, except above a certain level I think you need measurements to see what is left to be done / how far away you are from targets, otherwise you are shooting in the dark so to speak. You might hit the target but you will probably end up hitting stuff that didn't need to be hit (meaning lots of surface area covered with treatments) and wasting ammo (money in the case of acoustic treamtent).

[Ethan Winer]

above a certain level I think you need measurements to see what is left to be done / how far away you are from targets

Agreed, and emphasis mine to further agree.

--Ethan

[Glenn Kuras]

I do agree with Ethan and Byran, but it can tell you things like SBIR or if problem is coming from back/side/ceiling area. 

Glenn
GIK Acoustics

[gkinberg]

I am trying to use REW with my laptop. REW instructions state that an external soundcard is usually required with a laptop. Is there a way to determine if my internal soundcard is sufficient to use REW?
As an alternative, does HOLM Impulse also have this same idiosyncrasy? Is an external soundcard needed or can one use their laptop and the internal soundcard? Thanks for your help.

Garth