Are there any recommended "room dimensions" for B&w 800s speakers ?

[Eliav]

Hey
I have read several threads where members consider buying/not buying B&W 800s speakers based on their room dimensions. Others have indicated that this parameter should not play an important factor when choosing a speaker.
Focusing on the bigger 800 series (803 and higher), what would be your take on "ideal" room dimension to get the best out of the speakers ? (please exclude cosmetic/wife considerations..)

Thanks
Eliav

[Kobus]

I have a 4m x 7m "closed" room which really feels perfect for my N803's. Seating position +- 1-2m from the rear.

A friend has got 803d in a openish 5 x 4m room with good room treatment and it sounds perfect to me.

That said, neither of these might be ideal. ????

Kobus

[Eliav]

Hi
see, that's my question, what's ideal ? is there a scientific support for a minimum room size to match a certain speaker ? for example, I have read here in this forum memebers saying that the 802d ( compared to the 804s) "move more air" and hence require more room, or, that a certain member who had a 4x4m room was told that his room was "way too small for th 802d" and so forth.
having read most of the threads discussing room size it seems that room size never indeed was found to play a role in how the system sounded, rather , room acoustics and room treatment seemed to play a more important role.
I have not found in the B&W manual any indication for minimal room size for any of their 800 series.
More input on this ?
Thanks
Eliav

[JKalman]

Room dimensions are important for any speaker. Some proportions support modes that correspond to frequencies that are musical notes.

If a room is too small, in order to place the speakers with minimal room interaction, you will find yourself sitting too close to the speakers. You will also have early reflection problems that will skew the original sound.

The two web pages I am posting together give a good explanation of why too small a room won't work very well, with a little consideration. Since there are very few places in a room where speaker placement is least colored by the rooms dimensions and since you can't do much to change low frequency interaction with the room, you will have to sit close to the speakers in order to utilize a position that isn't colored by the room dimensions. The reason you shouldn't sit too far back is because once you go past the critical distance; the direct sound field loses dominance to the reverberant sound field. Of course, if you are willing to spend a lot of money you could have an acoustical engineer design you a sound studio that allows you to break some of these conventions, but it won't be the kind of pleasant sound you would want for personal enjoyment, but rather a good sound environment for editing music, quite dead sounding. Also, as the room gets smaller, your speakers get closer to the walls; with the 802D this would cause heavy bass reinforcement as well.

Link 1

Link 2

Why not be close to the back wall? If you are positioning your speakers for least room interaction, and you are sitting in the sweet spot, and you are near the back wall, then your room is likely cuboid, or you are placing your speakers symmetrically along the long wall, which is not preferable to placing your speakers facing lengthwise. Broadband diffusion (on say the back wall) when you sit too close does not have enough space to take effect, making lengthwise placement in a small room difficult. Also you are increasing the colorations due to room interactions. Cuboid rooms reinforce already dominant resonant modes because of shared or similar wall lengths.

Literally, you can place those 802Ds in a 5' x 8' space, but where will you sit, and how will it sound? Then, think about placing them in a 18.375' x 33.5' space which is similar to my dimensions. I don't feel I have enough width in my space for my comfort even with a little more than 18', I'm still a little close to the speakers in my speaker setup for my comfort (around 9'), but it gives the least skewed sound I've found so far. I started using the Cardas method for speaker placement (approx 5' from side walls and 8' from front wall) with my seating around 1.1 times the distance between the speakers, where the distance between them is 8.1 because it measured the flattest (my room has a few anomalies which make it not perfectly rectangular). I've moved them around a lot listening to the sound and taking a lot of ETF measurements, it eventually ended up back near the Cardas position... My ideal space would be big enough to put me more than ten feet from the speakers, which would also extend the soundstage more as well. In my current setup I would increase resonance at certain frequencies as well as extending them to a larger bandwidth by moving my speakers out further.

Many speakers are not built for near-field listening, so they won't do well in a small space where you have to sit very close to the speakers, especially when you consider many large speakers won't have time for the sound from the different drivers to integrate outside the cabinet. So, yeah, certain speakers are better for certain spaces. Many monitors are designed for near-field listening. Of course, there are always sacrifices, finding what speaker will fit your room with the least amount of sacrifices is key. Hope that all helped a little, there is more to it than I listed so I will list some additional sources. Sorry for anything I left out and any errors, I'm not an acoustical engineer after all. :P

Some good sources for a deeper understanding are, Master Handbook of Acoustics (F. Alton Everest) and Total Recording (David Moulton). Or articles on the AES website, if you are willing to pay for access. :W

On that website I gave you the link to, you can also take free courses, or take courses for credit if you want to pay for it.

[JKalman]

Here is one more link that explains why large rooms can have better frequency response due to clustering of modes.

Link 3

[Eliav]

Hi Jeff
Thanks for the detailed post. I think it answered at least part of my questions. I will be looking at the links you've listed and see if I can extract some more information out of them.
BTW ,I have used the Cardas formula to place my 803s in my 21'x19' room, I found this placement to yield the best imaging and bass-tight lower frequencies. I have also invested some time and money in acoustic traps which made a huge difference IMHO. Recently i have been thinking about the 802d, however, I am not sure how these big guys will sound in my room. how can one tell before making an actual move ??

Cheers
Eliav

[JKalman]

Your dimensions are fairly cuboid, so any speaker you put in there will have similar issues. With an electrostatic or magneplanar speaker you could place them closer to the back wall and avoid the problems you would have with using the Cardas method for cabinet speakers (e.g. - shared distance between the front and side walls causing frequency reinforcement).

You could probably get better results shaving width off the room. Then of course you will be sitting closer to the speakers if you want the least room interference. Unfortunately you can't get rid of a rooms resonant modes. The good news is, it isn't really a small room. The bad news, the 802D and up have a lot of bass output which would only further accentuate the reinforced bass frequencies in a cuboid room, especially if the distance from the front and side walls are similar enough. Likewise, if you use a speaker with less bass, you will still have areas in the low frequency spectrum that are not reinforced and you will lose out on nice bass output in those ranges. A sort of lose/lose situation.

The room dimensions themselves will effect any speaker you put in there though, just to be clear. I wouldn't agree "not to let your room decide what speaker you choose", but this is a situation where any speaker will have similar issues. Also, most speaker setup systems, such as Cardas, because of the room shape will place you either in the center of the room where critical distance will be at its peak, or further back where the reverberant sound field will be dominant. As you can see, these are all problems with the room itself, not the speaker, though with some types, like electrostatic or magneplanar, the Cardas formulas change placing the speakers closer to the back wall. you might want to check that out to see what kind of difference it might make as to your seating position. Good broadband diffusion on that backwall would probably be very helpful in your setup. I'm just using bookshelves in my room, but the length is already very long anyway, possibly too long.

Room treatment made a huge difference for me, both perceived and measured. Using ETF I found a nice lessening of the decay times when comparing before and afters. I've been using mineral fiber board 4" x 4' x 2' at the first reflection points and in the room corners temporarily, while I get professional consultation on renovating my entire room from Rives audio. With your situation, if you can throw down $1-2k, consultation might be a positive thing. I figured with all the money I spent on gear, I might as well go the extra steps and have an acoustical engineering expert fine tune my room, especially since it has irregularities.

Here is my setup in case you are curious, sans room treatments: My Setup

[JKalman]

Oh, here is a link on the same site as the first two links which lists the best room ratios, two spreadsheets on the site list all of the best ratios and all of the second best ratios as well. These apply to all speakers.

Link 4

[JKalman]

Oh, here is a link to an Excel file you can use to get theoretical information on perfectly rectangular room dimensions by plugging them into the worksheet.

Link 5

[Eliav]

"The room dimensions themselves will effect any speaker you put in there though, just to be clear. I wouldn't agree "not to let your room decide what speaker you choose", but this is a situation where any speaker will have similar issues"
Jeff, I have treated my room already with both bass traps and higher frequency traps. with the 803s in it's current position imaging and lower ends are EXCELLENT ! my question is if the 802d comes in,with same room, same position, same acoustics - is there a chance for a "boomy sound" instead of a great improvemnt ?
You see, my problem is a rich man's one :W ; my current setup sound great, I would however like to upgrade the speakers, Am I going to get disappointed by bringing in a too big speaker ? or, as you have mentioned, if the room sounds good with the 803s - is it reasonable to expect it to behave the same with the 802d?

Thanks
Eliav

[JKalman]

It depends. Do you feel that generally you could benefit from more "boom" in your room? Hehehe. There will be more "boom" in your room compared to the 803S because of the differences in the cabinets and woofer sizes. I don't know your preference for "boom", so I can't really say whether it will be too much for you.

I think you will receive great improvement over the 803S because of the marlin head, diamond tweeter and improved drivers. I would say, if you treated the room well, and the room is built, or treated, to relieve the pressure caused by excessive bass buildup, then go for it. If you didn't though, you might have large bass buildup in the resonant frequencies, the kind that might make your ears fatigued quickly. I can't give you a certain 100% yes because I don't know all of the particularities of your room and I wouldn't want to presume to be that much of an expert on your room or you.

I know it works well in my space, but mine is a lot longer while having similar width. You certainly have the width, it is the length of your room which worries me. I wish I could be more help.

Sorry if I don't reply for a few days, I'll be on vacation in Nantucket with my wife until Thursday.

[Eliav]

Jeff
Thanks, your input is very much appreciated. Have a great vacation ! 8)
Eliav