real wood paneling- artto??

[colterphoto1]

Well, gang, I've been moving into and remodeling this old 1950's ranch home for several months now, and it's time to make some major decisions. The living room will be my photography gallery, with minor sound system and projection tv beautiful new hardwood floors but it's VERY live. I've decided against putting any major system in basement until further landscaping and waterproofing can be done.

So I'm stuck using this enormous room in center of home for my main listening station and HT. Here's the basics, and I'll try to forward a diagram and photos shortly.

The room is rectangular 26' long by 17-6 wide. Ceilings are 1" real plaster and flooring is very thick carpet and pad over framed floor over basement. The walls are very unique however. They are 3/4 " thick real 'knotty' pine that are original to the house and are nailed directly to the studs. The best I can tell there is almost no insulation in the two smaller walls which are exterior walls of the home. Both these narrow walls contain entry doors and very large window units. There is a doorway or hallway in each corner of the room. Along the center of one of the long walls is a masonry fireplace unit 11' wide, floor to ceiling Bedford (limestone) cut stone.

Right now I've got my setup along the back wall, one of the short walls which puts it right in front of one of the large windows. There are heavy curtains which are okay to keep closed and I may put some insulation board behind them. Nothing vibrates though. I've got my seating position about 2/3 back from this, so I can visually see the fireplace to the left, yet view the 35" tv in front of me. The Cornwalls are about 8' apart, centered on a 17' wall and toed in pretty heavily. RC7 under TV and RB3II as surrounds slightly behind listening positons.

So far I'm pretty happy with things, but of course the ears will adjust to the acoustics. Does this room have any hope? Or should I just sod it all and move the basement and start over?

Suggestions would be helpful. I'm up to the challenge of building whatever bass traps are necesssary although I'd rather not cover up the paneling very much if I can help it. Furniture and draperies have not yet been purchased so they could be used for acoustical purposes if necessary.

Thanks, and I WILL LISTEN TO YOUR SUGGESTIONS!!!!

Michael

[colterphoto1]

sorry, I know you need ceiling height to compute. standard 8'.

[artto]

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On 8/19/2004 2:46:48 AM colterphoto1 wrote:

So far I'm pretty happy with things, but of course the ears will adjust to the acoustics. Does this room have any hope? Or should I just sod it all and move the basement and start over?

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This depends on what you want out of the system, how important music/sound reproduction is to you, and what kind of compromises you are willing to live with.

I dont see any problems with a room being live. Its more about how reflections are controlled. And its not about one range of frequencies or another, its about broadband, the full audio range.

Your room is similar in size and proportions to my room, so it should be in the ball park.

I guess my first comment is the location of the Cornwalls. IMHO its a shame to have such large and powerful speakers only 8 apart in such a spacious room, especially if youre going to be sitting so far back from them. And if youre sitting 2/3 of the way back into the room (relative to the long wall), I dont see the need for toeing them in so much as you wont be in the direct sound field of the speakers, which is the primary reason for toe-in.

The curtain in the front of the room is not a bad thing, but I would avoid too much absorption on the front (speaker) wall. That technique (dead end/live end) is used primarily in small recording/mixing studios where the engineer is using near-field monitors, and is usually sitting much closer to both the speakers and control room front wall/window.

A lot of what can be done depends on what level of performance you desire and what you are willing to do with the room. There really is no substitute for starting from scratch. That being said, even then, you will still most likely make mistakes along the way. Everyone does. Many will be correctable, some will not.

[colterphoto1]

Thanks Artto,

I take it that your post menas that in terms of room dimensions and nodes then, I'm in the ballpark means that I've got many nodes, therefore no serious bass problems re standing waves, etc? I worked out the ratios and 8x17-4x 26 is 1:2.13:3.25, all of which are a long ways off from the 'ideal' ratios I've been reading about. They do seem to have nothing in common in terms of doubles/halves which seems to be a good thing. Would you run these through your calculator please?

From my old PA days, I noticed that lots of studios installed rooms with wood walls for a 'warm' tone when recording acoustical instruments like guitars, cellos, etc. I was hoping that this would be advantageous. I do like the sound of this room better than those in the house that are entirely plaster walls. Plaster is much denser and live than drywall. Better for construction, worse for sound IMO.

The curtains behind speakers aren't especially heavy, they just shield the glass behind. I'd say it's about equal to a solid wall. Not looking to make that wall especially 'dead'. WIth the amount of door ways and especially with the grand fireplace, there's almost no other place for the system except the short wall adjacent to FP. I'm actually sitting maybe 1/2 way down room, the far end of the room is the 'dining hall' and entry as the home has no formal dining room.

My only other possible room layout would involve facing the fireplace (on long wall), which would put the Corns about 15' apart, then I'd have to get flat panel or proj. tv to mount on beautiful stone hearth. I could then sit about 12 ' from that wall, view FP, tv, and have spacious sound field. I could also then open the curtains on what now is the equipment end of the room. This might also be good karma as my back won't be to the front door. Does this sound like a better plan?

Thanks for your valuable input!

Michael

[artto]

Theres more than one opinion on the range of ideal room proportions. The one youve probably read about most was developed by Richard Bolt in the 1940s and is based on his preferences. Another popular and more recent one developed by Richard Walker of the BBC in 1996 is the one I currently use. Its a bit more complicated. Your room meets its criteria.

Wood varies greatly in hardness and absorption/acoustical qualities. My favorite concert hall, The Foellinger Great Hall, U of I, Urbana, (designed by architect Max Abramovitz, who Bolt consulted with on the United Nations Headquarters), uses Butternut for much of the interior wood surfaces and was choosen for its specific acoustical properties. The finish used on the wood will also affect its acoustical properties. Keep in mind that there are also special acoustical plasters (which you can be quite sure you probably dont have).

In all seriousness, its very unlikely that the curtains are providing anything equal to a solid wall. Curtains typically absorb while solid walls primarily reflect sound. Most curtains need to be rather thick and heavy to provide much absorption, otherwise the sound mostly goes right through and gets reflected off the surface behind it.

I like your second plan better.

[DrWho]

ditto on the second plan idea

[colterphoto1]

Okay, lets presume I like the furniture placement options and wider soundfield that placing my system along the long wall on either side of the fireplace. I have the 3/4 knotty pine walls, heavily padded carpet floors, and plaster ceiling of the above given dimensions. I am starting with a clean slate in terms of viewing medium, since it would look awkward to have a 35" direct view monitor either beside or over my fireplace. (the firebox is at floor level, built flush into bedford stone wall floor to ceiling and about 8 feet wide in center of room). The Left Cornwall will be in front of the stone wall, and there is a 3 foot offset to the right of firebox that would be ideal for equipment tower and right Cornwall. I'll either have to use a second projection system or or go to flat screen for this to look 'right' (there is already a Canon projection system in the adjacent photo gallery room.)

Acoustically, none of the surfaces can change drastically for now, other than I am open to putting bass trap units behind the curtains on right wall (about 6' wide x 6' tall), as they don't let in much light anyway. I would be willing to place diffusers/bass traps on other wall surfaces so long as they don't take up a large % of wall surface. There are doorways or halls to every corner, so no speakers or diffusers can be placed there. Furniture is wide open. I may go fairly modern for the sake of the 50's home, but placement is not decided and I can purchase furniture in terms of it's sound deadening properties if necessary.

What should I consider at this point? I'm probably going to upgrade Dolby ProLogic Yamaha RVS850 for a bigger 6.1 Yamaha, probably 2400. Center for now is RC7 and surrounds are RB3II's, although I'd like to upgrade to more Corns or at lease RB5? for surrounds. Center may change to heritage line per all the heat I'm getting about timbre. Sub will definitely be upgraded from current inaudible KSW-15. I have two JBL 4562 (single 18" in ported cabinet) that I could install in the offset behind the right Cornwall and power with QSC or Crown amp. The sub could point out to the right, so it would bounce off the right wall, about 6 feet away.

Any help would be appreciated. I'm looking to moving forward with curtain/furniture purchases fairly soon. THANKS!

Architecturally, what can/should I do?

[DrWho]

I personally would wait until you've purchased all the equipment that you plan to use for an extended amount of time. The reason being is that different speakers will have different resonances, dispersion patterns, blah blah blah. A "treatment" for one speaker, may very likely hurt the sound of another speaker.

[colterphoto1]

The only major change for now will be the receiver. With the same compliment of speakers, couldn't I get 'close' with any acoustical controls?

[DrWho]

Oh, here I thought you were planning on purchasing all of the new toys within the next year...

For starters, I would suggest starting with some bass traps. Bass tends to be how most people rate sound systems and it usually results in the biggest bang for the buck. Diffusion and absorbtion for controlling early reflections and reverberation tend to be not as noticeable. The main reason is that when you walk into a room, psychoacoustics tells us that your brain automatically compensates for the room and anticipates the sound in consideration of the environment. Also, some reflections and reverb are indeed very good attributes to a good sounding room which means it takes some work (or trial and error) to decide what sounds best.

[colterphoto1]

I've done some reading on the bass traps subject. Hey, it's practically required reading in this Forum per artto! Read Edwin's and others so I understand the theory of bass building up and controlling it via the suprisingly heavy membranes of various sized traps.

Question: How do I determine which frequencies need 'taming' and how do I determine which size/membrane thickness trap to build to make the necessary correction. I'm absolutely certain some of this is required in EVERY listening room (thanks artto) but obviously wish to keep it to a minimum for the sake of aesthetics. I do have test tones and ratshack SPL meter. Is more testing equipment necessary to locate the offending frequencies? How do I engineer the bass traps?

Thanks,

Michael

[edwinr]

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On 8/23/2004 7:58:13 PM colterphoto1 wrote:

The only major change for now will be the receiver. With the same compliment of speakers, couldn't I get 'close' with any acoustical controls?

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It's always a problem balancing the 'ideal' location for your speakers vis a vis sound quality,against the need to fit in your audio visual needs. My room size is similar to yours, probably around a yard shorter, but I've got double brick construction, and no real door or window impingement to worry about. I just set my speakers up first in the best sounding location, and then installed my projector screen, equipment rack, and furniture to suit my listening position. You obviously have a more complex room setup, and it won't be so easy.

I had a thought. I can't contribute technically to this discussion, but if you were going to buy a new receiver, why not consider one of the new Yamaha models that have a built in room correction mode? I know that the room correction is adjusted via a limited number of freqency bands, but the end result, apparently, is quite workable. In this way you would avoid getting too tied up in matters technical for the time being, and concentrate on renovating the basement for a future music/home theatre room. Just a thought for what it's worth.

[colterphoto1]

Thanks for the input Edwin. Yes, I'm planning on getting one of the Yamaha receivers that has the 9 band parametric eq with calibrated mic. However, after reading artto's posts for several months, I'd rather get the room right if at all possible. It sounds like eq is only a partial solution to boomy bass. I wonder if the receiver gives a channel of eq for each of 6 amp channels or just the main two? ?? It would also be nice if you could run the eq 'program' then still get in and tweak the eq a bit for personal taste.

Yes, placement is going to have to be based on aesthtics, I won't be able to move the Cornwalls very much other than scooting them out from back wall a bit.

[artto]

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On 8/25/2004 1:15:46 AM colterphoto1 wrote:

Question: How do I determine which frequencies need 'taming' and how do I determine which size/membrane thickness trap to build to make the necessary correction. I'm absolutely certain some of this is required in EVERY listening room (thanks artto) but obviously wish to keep it to a minimum for the sake of aesthetics. I do have test tones and ratshack SPL meter. Is more testing equipment necessary to locate the offending frequencies? How do I engineer the bass traps?

Thanks,

Michael

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Thats the reason broadband frequency treatment is advocated. So that all frequencies get treated relatively equally. Its very rare that only one or two acoustical problems exist in any particular situation. And many acoustical problems are interrelated. In other words, the same thing thats causing some kind of frequency response anomaly may also involve reverberation time or impulse response, etc. It may be helpful to think of it like a teeter-totter, bringing the level down on one side brings the level up on the other. The areas closest to the middle which dont need any treatment stay relatively the same.

So basically, IMO if you start trying to engineer very specific solutions to very specific problems in such small spaces, youre probably going to make the situation worse in another area, hence the use of broadband treatment.

Master Handbook of Acoustics by F. Alton Everest has pre-prepared tables/data of various type of bass trap construction/sizes. But quite frankly, unless you have access to a calibrated microphone of known response, and some more sophisticated real-time analyzer equipment/software (and know how to interpret the data), youre probably not going to be to successful at sorting out specific problem areas using a more technical approach, much less deciding how to best treat it (even I use the technical aspect to simply confirm what I'm hearing). Following the basics initially (getting good uniform BROADBAND diffusion and absorption) and using your ears is the best approach. Look at all the predetermined acoustical engineering that was put into Lincoln Centers Avery Fisher Hall. It was supposed to be an acoustic marvel. Years later it had to be gutted and acoustically rebuilt because someone decided to ignore some very basic acoustic principals, and tried to reinvent the wheel on their own terms.

[colterphoto1]

Thanks Artto, unfortunately its not what I wanted to hear. I was hoping that a few, well placed traps could help my room. I'm willing to do so room modification to improve sound, but I cannot justify covering large areas of my homes beautiful wood paneling with massive sheets of fabric and plywood bass traps as I've seen in some of the articles you've pointed out. I would not be able to obtain a seal between the sides of the trap and the wood paneling because I can't apply sealant to paneling.

Is there some type of all-purpose free-standing trap I could construct, maybe as a low table behind sofa or room divider? I'm thinking maybe something around 5-6 feet long, up to 4 feet high and between 6-18 inches wide. It could possibly be stuffed with the dense fibreglass and each side could be a different thickness 'membrane' to help trap broadband sounds.

If I'm willing to lose a large window area, could I construct a 6x6 foot trap arrangement that would be braced within the window opening. It would be behind a curtain, but I don't think that would affect the low-freq control we're talking about here.

Artto, I'm not looking for an easy, cheap fix to a problem I'm not sure exists. I'm just trying to get an understanding for what can be done to improve an average home listening room.

Thanks,

Michael

[colterphoto1]

Thanks for the discussion gang, but again I ask, is there NOTHING I can do architecturaly/acoustically for my listening room that will improve the sound without adding massive square footage of bass traps?

Thanks.

[colterphoto1]

okay, I'm moving furniture right now, so from left to right across my hearth room (26x 17) on the long wall, it's the following:

4'dual doors to gallery, then in front of stone hearth it's Cornwall L/ 35"sony over RC7 2'stand, 1'space, firebox, then off to the right slightly inset in wall (hearth juts out 2 ') it's CornwallR, and equipment rack.

Problem is that no matter what I do, until I can hang plasma over firebox or get another projection system, I can't quite get 35" centered between Corns, but at least I can get the 12' equilateral triangle between both Corns and prime seating position. RB3II's will be temporarily on back wall about 5 ' behind me, on tall antique cabinet or upright piano, which would be about 4 1/2' above floor, but only about 5-6 feet apart, hope this works for now.

I'm also off to pickup a Yamaha RXV2400 receiver this afternoon. Any hints for a new DVD player? I know to get progressive scan and I like Sony for it's slow motion and remote control. Not so much interested in SACD, etc. Any hints??

thanks.

Michael

[colterphoto1]

just bring this back up top, so is there NOTHING I can do to improve my room?

[artto]

OK, lets start over. First some basic concepts. Room modes primarily affect the lower frequencies. However, the bass range comprises nearly half of the audio range. Below 200 Hz the acoustics of different locations in the room are dominated by discrete resonances (modes). Above 200Hz these resonances become so tightly packed in frequency and space that the room behaves quite uniformly and is best described by its reverberation time. 20-200Hz still comprises the first 3.5 octaves of music.

Low frequencies have longer wavelengths. Where do the longest possible dimensions in an enclosed space occur? They occur between opposite room corners. Just as a Klipschorn uses these corner intersections to produce low frequencies more efficiently, the same is true of the rooms resonant modes, they tend to build up in the corners. The walls reflect the sound back towards the speaker where it coincides with the next cycle of the same frequency, reinforcing it. However, on its way back to the speaker, at one or more locations (depending on the frequency), the wave will be out of phase with next cycle coming from the speaker. This causes a null, or attenuation of the sound pressure at that location. The purpose of a bass trap is absorb the low frequency build up in the corner so it doesnt reflect back to the speaker and cause as much cancellation in other parts of the room. Therefore, the corners are the first logical place to install bass traps. These are typically broadband devices. They absorb mid and high frequencies too. Trying to engineer a bass trap to absorb specific frequencies for a specific situation is relatively time consuming, difficult, and not necessary. At this point were not as much concerned about attenuating peaks as we are reducing the dips in frequency response. There are many commercially available bass traps of many different designs with a wide variety of aesthetics. Use them in the vertical corners first. If more trapping is needed, use the horizontal corners.

The rest of the frequency range (above 200Hz) is most characterized by the rooms reverberation time. Here both absorption and/or diffusion can be used, preferably some combination of both. In most domestic situations things like carpeting, curtains and various furniture act as absorption and diffusion devices. This is the point at which rooms like mine begin to separate themselves from the typical home listening environment. Furniture, while helping to diffuse the sound, can also cause unwanted near term reflections which dilute imaging and definition. Therefore, if you want the ultimate in sound reproduction in a relatively small space (acoustically speaking), you need to get rid of the furniture near the listening position. If you do this, the smooth, flat surfaced walls then become a problem causing ping or flutter echo between the parallel surfaces. How much absorption and/or diffusion treatment your room needs is dependent on whats in the room. From a strategic standpoint, the first reflection points should be determined. This can be done by having someone hold a small mirror (6 or so is fine) flat against ceiling and wall surfaces and move the mirror around until you can see the (mid and treble) speakers reflection in the mirror from the listening position(s). These reflection points are candidates for absorption or diffusion treatment. Keep in mind that various absorption/diffusion treatments can be camouflaged as artwork, architectural details or be furniture such as book cases.

[colterphoto1]

Thanks for your gentle reflections on this topic. As it currently stands, my system is now centered about 1/3 from right along the fireplace (long) wall of my hearth room. I had to do this for asthetic reasons and will post diagram/photos shortly. Basically, along one long wall, it's about 10' of wall, Cornwall, fireplace, 35"tv with RC7 underneath, rack of components, door to garage, corner of room. Then along the adjacent short wall to the right, I have the other Cornwall about 6 ' from corner angled heavily towards listening position. This fits the asthetics of the room and I now have two Corns with about 15 feet between them, with 35" Sony pretty well centered and listeners about 10-12 feet from TV. Pretty close to the equilateral triangle, even if I've 'turned the corner' to do so. The Yamaha RXV2400 seems to have taken care of the slight timing differences and I've yet to fine tune the positions of the rear surrounds RB3II. Wondering if this slightly askew approach is possibly helping in the reduction of standing waves/ corner problem? Of course the Corns are now working into somewhat different sonic spaces, but I can't seem to notice after eqing. The Yamaha calibrated mic unfortunately has only 7 parametric bands which stop at about 60 Hz, so it does nothing to tune or tame any problematic lower frequencies.