Room Treatment Help

[rigma]

Below is a link to my room layout.

http://www.jubilation.ws/Room.html

I have 10 of these on order.

https://www.readyacoustics.com/index.php?go=products.configure-chameleon-bass-traps

and will be building some QRD RPG style diffusers and willing to buy some RPG Skyline diffusers.

I now have the RplusD software working and have identified some early reflections and there location (thanks miketn). The early reflections were off the angled ceiling just above and behind the listing position and at about 4.5 ms and only about 6 db down.

I would appreciate input from others on possible improvements I could make to the room and location for the traps and diffusers.

rigma

[gaspr]

Great looking room Marion!! Looks like you must have some good hunting stories as well...(Former Whitetail trophy hunter myself). I am certainly no expert and am quite sure sure the real experts will weigh in soon...but it looks like the steeply sloped ceiling is going to cause you some grief because it wants to focus the sound energy down onto your listening area. Have you looked into phase gratings such as Auralex's "Spacecoupler"? I really like the way they look and with your woodworking skills, you could easily build your own. I would suggest suspending a layer of them somewhere above where your ceiling fan is. I also like the look of their Spacearray diffusor...maybe something to consider on your back wall/ceiling??

I would be a little bit careful about putting to many "bass" traps into the room. These would be more accurately described as broadband absorbers and as such, will be absorbing over a wide range of frequencies and may start to make the room sound too dead. You are definately on the right track with the measuerments you are doing. Good luck with your project!

Garth

[mas]

Yes, I was hesitant to jump in initially for the above reason...

Are you open to re-orienting the room along the long axis so that the ceiling ridge runs perpendicular to the plane of the KHorns? In other words, so that the primary speakers are not playing into the sloping ceiling that is going to return the specular reflections directly back into the listening space...

As is, the rear sloping ceiling is going to create a very serious problem.

Oriented along the long axis, you have quite a few options, and the ceiling is largely removed as a detrimental factor and can in fact become an asset.

[rigma]

Mas,

I have temporarily tried turning the room as you suggested
several times. It did help the imagining but it killed my bass
response. I think it was due to all the open areas behind the listing
position, 2 sets of stairs and bar area etc. It would also be a major
headache to do on a permanent basics because of inaccessible under
floor
wiring... satellite, antenna, speaker, power etc.

I would much rather keep the orientation as is and use treatments if that will not be too much of a negative.

rigma

[rigma]

Garth,

Thanks for your response. We are no longer hunters
since we sold our share in the hunting club on the Mississippi river
about 6 years ago.

I will look into the devices you mentioned as I am not familiar with them.

rigma

[gaspr]

Are you open to re-orienting the room along the long axis so that the ceiling ridge runs perpendicular to the plane of the KHorns?

Now Mark...those aren't just KHorns...[:|]

[Colin]

RealTraps has a product similar to the ones you chose and a room like yours:

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

They say “Generally speaking, most rooms need as many bass traps as you can fit and afford. Although it is definitely possible to make a room too dead at midrange and high frequencies, you probably can't have too much low frequency absorption. The effectiveness of bass traps is directly related to how much of the room's total surface area you treat, which includes the walls, floor, and ceiling.”

In stereo speak, the front wall is behind the equipment, while the back wall is behind your head. My guess is that your high, angled attic ceiling on the front wall provides excellent reflections, directing sound down towards the listener. While high, angled ceiling on the back wall greatly confounds the sound, sending late reflections that muddy the music.

As you can see from the pictures at the RealTraps site, their panels are distributed not just on the back wall, but also at the peak and the corners.

BTW, what color fabric and frame did you get? And what is the material inside the panels?

[rigma]

Actually the Khorns are no longer there, the Jubilees have taken their place.

Colin I ordered the Sand color frames and Bone colored fabric from Guliford of Maine. By the way I am using Owens Corning 705 fiberglass instead of the 703.

rigma

[mas]

[][:$]

OK, granted My bad...

I didn't examine the speakers in a great amount of detail except to note that they were oriented along the long wall.

Yes, you absolutely can apply too much absorption in the name of bass traps. Too much absoprtion is too much absorption. And OC705 simply is more effective in absorbing a broader range of frequencies. It just absorbs 'more'. More absorption is NOT better. It is detrimental.

You can fight the room or you can turn problems into assets. Playing to the inwardly sloped ceiling that is in effect the short wall is not a winning proposition for a number of reasons. You are going to need substantial diffusion MORE than absorption. PM me and I can give you a few specific techniques that you can use on the ceiling.

Just what are the vertical polars of the 402s??? []

Edit:

After talking, aside from feeling pretty silly for a number of reasons, I think we can turn lemons into lemonade...Call me or leave your number in a PM and I will give you a shout!

[DrWho]

I would much rather keep the orientation as is and use treatments if that will not be too much of a negative.

You would have to do some real funky stuff to fix the problems imposed by that ceiling. Acoustically speaking, I agree with Mark that the other orientation will be far superior.

The bass problems you experienced with the other configuration are more likely a function of standing waves - not necessarily that you have open space behind you. However, with your listening position pushed up to the rear wall like that, you're probably sitting in a pressure zone, which will certainly accentuate the lows...which is great if you like bass, but not too great if you like clear mids/highs (due to the very strong comb-filtering / smearing).

Are you trying to treat for a single listening position, or multiple listening positions? You might be able to get aggressive with the treatment if it's just one listening position...

[gaspr]

Pardon my ignorance if I am wrong here but the fact that there is good bass response in the present setup but not when they are on the short wall tells me that the lack of bass has to be caused by some large cancellations?? You might think about concentrating or stacking your traps so that they might help remove some of the modal issues. It would be a lot of work but if they could be stacked at the ceiling peak, they might be in a good place to help the bass.

[mas]

Pardon my ignorance if I am wrong here but the fact that there is good bass response in the present setup but not when they are on the short wall tells me that the lack of bass has to be caused by some large cancellations?? You might think about concentrating or stacking your traps so that they might help remove some of the modal issues. It would be a lot of work but if they could be stacked at the ceiling peak, they might be in a good place to help the bass.

You can't restore a null with traps nor equalization.

Also, your perceived lack of bass may also be a result of the room loading of the bass bins due to their placement relative to the walls and surfaces.

Traps are not a magic solution. They can be used to reduce bass resonance (persistence in the time domain) and they can be used as simple absorption. But the tendency here to run for more and more absorption, be it called absorption or bass traps, is not a panacea. The focus on this one technique is akin to using amputation to cure whatever ails ya. And it should be rather obvious that this is not a very future oriented solution.

Especially if you are going to persist in playing to the short wall with an inwardly sloping ceiling, you NEED to get measurements. Lots of things are going to be dependent upon the polars of the speakers and the interaction in a very complex space. And you are going to need to measure the modes and identify their location, as this is a very convoluted space. But my off hand guess is to line the horizontal vaulted ceiling intersections with corner traps of OC705 or Roxul.

Except as absolutely necessary based upon measurements, I would avoid using panel bass traps, as you are going to very quickly deaden a room that is going to be dominated by some very nasty focused specular reflections and interacting coupled tuned spaces.

I normally prefer the long wall for speaker placement, but the ceiling presents an overwhelming challenge and is the 60 ton elephant in the room..

Short of a concave sloped ceiling, I honestly would have a hard time creating a more problematic space oriented as it is. How's that for sugar coating? []

I know there are lots of personal precedence for leaving the room oriented as is, but I personally would not - but then I have the luxury of dealing with this from a purely voyeuristic perspective concerned only with the acoustics of the space...[]

If you want to explore a few ideas and options - regarding whatever orientation you ultimtely choose. PM me and we can chat..

EDIT: As mentioned above: I think there is a nifty and elegant solution that can turn this space into an asset! Call me.

[mikebse2a3]

I thought I would add a few more current pictures of Marion's room setup.

No doubt rotating the setup 90 degree to the right using the right wall for the Jubs would simplify things and I personelly would consider building a large area false wall(composed of difussers) to locate 10' to 15' behind the new listening position and thus blocking the stair/wall from the direct signals. I believe this would help support the lower frequencies since otherwise the listening seat is really located approx. in the very center of the room and the rear diffusion created would be a large benefit also.

I do understand why Marion is hesitant to shift things around based on how they want to use the space and video setup.

Back Wall Cavity is also a complication area that might be of some help by centering the couch more in front of it since as you can see from were we had placed one pillow to help curb sum of the early reflections.

mike tn

[mikebse2a3]

Right Jub Area

[mikebse2a3]

Front/TV

[mikebse2a3]

Another shot of right wall.

You can see why they really hate to shift the Video setup to the right wall.

Marion begining to look at the ETC with RPusD.

[mikebse2a3]

Left Wall / Stairs and my Linda (see real evidence you can have a girlfriend or wife and Jubilees) with Marion and Becky's beautiful Jubilee.

Becky and Linda the Jub Girls[]

Hey Richard can you get your wife to pose with the Jubs?[]

mike tn

[Chris A]

RealTraps has a product similar to the ones you chose and a room like yours:

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

They say “Generally speaking, most rooms need as many bass traps as you can fit and afford. Although it is definitely possible to make a room too dead at midrange and high frequencies, you probably can't have too much low frequency absorption. The effectiveness of bass traps is directly related to how much of the room's total surface area you treat, which includes the walls, floor, and ceiling.”

In stereo speak, the front wall is behind the equipment, while the back wall is behind your head. My guess is that your high, angled attic ceiling on the front wall provides excellent reflections, directing sound down towards the listener. While high, angled ceiling on the back wall greatly confounds the sound, sending late reflections that muddy the music.

As you can see from the pictures at the RealTraps site, their panels are distributed not just on the back wall, but also at the peak and the corners.

BTW, what color fabric and frame did you get? And what is the material inside the panels?

I was very surprised at the effectiveness of two Ready Acoustics "Ultra Bass Traps" in the front corners above the speakers for my room. Rigma - I understand this won't really work for your pitched ceiling - there isn't really a good corner at the speakers but any corner is probably much better than a floor/wall line or a flat-wall-mounted trap.

In looking at the pix of your room I see your listening position fairly close to the back wall. I don't know if traps or diffusers are going to strongly affect the balance for this position. If the path length from your speakers to the pitched ceiling behind your head then down to your listening position is less than about 50 feet, then that reflective pitched ceiling area behind your head probably isn't your friend. If you experience loss of bass in any position then I think you are probably sitting in some sort of mode null--and this is almost inconceivable for extreme low-bass frequencies but check those ceiling reflection modes and consider trial bass traps hung up high with diffusers/reflectors hung below that. I really can't find much in the way of a deep bass null point in my listening area but I don't have a pitched ceiling. That in itself is probably a clue--arranging reflective panels to approximate a flat ceiling could be one thread of pursuit.

[update: I see from the pix that your ceiling has a horizontal peak section. I'm sure you've thought about it but suspending traps from that center section would be a prime location. Some pretty aggressive wall-mount diffusers along the ceiling (both surfaces) might also help to break up those strong reflections. Try shining a flashlight from each speaker location upwards from horizontal to 30 degrees up angle at night with lights out in different directions. Look at the reflection bounce areas of max brightness - those are candidate areas for diffusers (higher frequencies).

From Geddes, et al:

"It appears then that the best rooms for serious
listening would have a great deal of low frequency absorption accompanied by
very low amounts of high frequency absorption (i.e., the exact opposite of what
is usually done). Also consider the fact that absorbing material placed in a
small room is orders of magnitude more effective than this same material placed
in a larger room. That’s because virtually all sound absorption takes place at
the enclosure boundaries and a sound wave in a small room strikes these boundaries
many more times in a given time period than it does in a large room. Thus, even
small amounts of sound absorption in a small room can lead to an over-damped
condition - especially at the higher frequencies.

The earlier and the greater in level the first reflections are, the
worse they are. This is true up to a point - about 20 ms - after
which the perception of a refection is usually positive and perceived as early
reverberation and spaciousness. In small rooms, the first reflections can never
occur later than 10-20 ms (basically the definition of a small room), so the
first reflections in small rooms must be thought of as problems that cause
coloration and image blurring. These reflections must be considered in the design.

Reflections become less of a problem as coloration and image shift at
lower frequencies.
Below about 500 Hz. early reflections are not as much of an issue. The ear has
a longer integration time at lower frequencies and it has a poorer ability to localize
resulting in a lower sensitivity to early reflections. Image location is
strongly weighted towards higher frequencies.]

Regards,

Chris

[mas]

If you have a free minute, give me a call back.

I think I have a solution that can make that room really compliment those great looking speakers!!!![]

[]

[Coytee]

Hey Richard can you get your wife to pose with the Jubs?

Would it be politically incorrect to have her standing there with a scowel on her face flipping me (the camera) the bird with both hands?

Cause I could probably get that shot!

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