quote: Louis Bornwasser

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The roll off specified is designed for all rooms.

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And that is a problem. Smaller rooms, when using an RTA and pink niose, require {LESS} roll-off to avoid sounding {dull}.

Edited text in {}

The manual for a Goldline RTA goes into detail explaining the differences in roll off for large and small rooms, and the reasons why. (Has to do a lot with reflection times affecting the response at higher frequencies.)

I think there is a Goldline manual in our "Manuals" section here.. unfortunately, I sold my Goldline and don't have the manual anymore.

[ 12-05-2008, 07:08 PM: Message edited by: Tony Bandiera Jr ]
 

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Posted by Max Biela (Member # 1919) on 12-05-2008, 02:56 PM:
 
It is the other way around: very small rooms require an almost flat EQ with very little roll off. See SMPTE paper published in the "Technical Guidelines for Dolby Stereo Theaters" in the manual section.
 

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Posted by Cameron Glendinning (Member # 3516) on 12-05-2008, 03:05 PM:
 
I agree with Max, close to flat in a small room
 

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Posted by Tony Bandiera Jr (Member # 2365) on 12-05-2008, 07:06 PM:
 
Yep, Max is right, I had that backwards.. my bad.. I'll edit the original post..

Sucks getting old...
 

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Posted by Pete Naples (Member # 761) on 12-09-2008, 03:39 AM:
 
OK Here's a quandry.

Define a small room?

Dimensions/Volume, or Nº of seats?
 

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Posted by Bernie Anderson Jr (Member # 410) on 12-11-2008, 06:44 PM:
 
Small room: small screening room with maybe 10 seats to a small multiplex auditorium with maybe 50 seats (35'x50')
 

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Posted by Steve Guttag (Member # 268) on 12-11-2008, 07:06 PM:
 
I tend to sub-divide the small rooms into the less than 40-feet from screen to rear wall. The Very-Small room for me is on the order of 20-feet from screen to rear-wall.

Like any EQ...use the analyzer but you best listen to your result with known film (a track you have heard in several rooms) and preferrably with several different pieces of material and dialog as well as music better be part of the material.

Steve
 

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Posted by Scott Norwood (Member # 30) on 12-12-2008, 08:09 AM:
 
Semi-related question: some setups and rooms seem to sound really great for music and lousy for dialogue, while others are the opposite. Why? Is it the extend to which the room is "too live" or "too dead" (what is the technical term for this?)? Is it the setup (EQ, crossover points, etc.) of the system?

Large rooms also seem to have low-frequency issues. I'm familiar with one (large 1920s house) that has a nasty bump at around 200-250Hz. How does one go about fixing something like this? Is it wrong to try to fix these issues with EQ alone? Is there material that absorbs certain frequencies that can be installed and, if so, how does one know where to install it and how much to use? Is it just a matter of trial-and-error? What about rooms that have dips at certain frequencies?
 

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Posted by Louis Bornwasser (Member # 3063) on 12-12-2008, 10:12 AM:
 
The larger, the more reflective room; you will have dialog problems. (if it is really large and reflective, you may have to EQ the normal way, then corrupt the eq to aid articulation.) You do this with all channels off except center; work only with dialog; when finished eq the other channels normally. Lastly, raise the center only 3-6 db if needed.

I feel like a real old timer on this since this was normal procedure in the 1930-1950's. Louis
 

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Posted by Robert Minichino (Member # 3495) on 12-12-2008, 01:04 PM:
 
From the opposite perspective (3000 seat house), Louis is absolutely right. Our theatre sounds great on music with minimal EQ, but dialog is unintelligible without a substantial and wide hump around 400Hz in the center channel.

For deciding what a small room is, my guide would be a combination of the largest dimension and room volume. The larger the largest dimension is, the lower in frequency the lowest room mode is, so that dictates your bass frequency response. The larger the volume of the room the less high frequency reverberation there is with respect to low frequencies.

In almost any conceivable home theatre or equivalently-sized screening room I'd run without EQ (or EQ so speaker's near field response is flat) on the high frequencies, and use a combination of room treatments and EQ to get a slightly rising response as you go down in frequency from 120Hz (3dB/oct) with no obvious interaction from room modes. It's been my experience that this combination gives the most "real" bass response in smaller rooms.
 

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Posted by John Hawkinson (Member # 1135) on 12-12-2008, 05:12 PM:
 
So, err, why are people asking what defines a small room? EQ the room to the curve and see how it sounds!

--jhawk
 

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Posted by Pete Naples (Member # 761) on 12-13-2008, 02:26 AM:
 
Just interested in what people consider a small room, nothing more.

I've got one tiddler in the Republic of Ireland, it aligns with very little action from the equalizers and sounds great. I put a lot of this down to the fact that you are sitting practically in the throat of the speakers. You are hearing more direct sounds as opposed to the predominantly reverberant field you would hear in a large room. The room being very well damped is helping matters too.
 

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Posted by Christos Mitsakis (Member # 143) on 12-13-2008, 03:03 AM:
 

quote: Scott Norwood

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some setups and rooms seem to sound really great for music and lousy for dialogue, while others are the opposite. Why? Is it the extend to which the room is "too live" or "too dead" (what is the technical term for this?)?

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quote: Scott Norwood

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Large rooms also seem to have low-frequency issues. I'm familiar with one (large 1920s house) that has a nasty bump at around 200-250Hz. How does one go about fixing something like this?

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