[PLMONROE]

New room for listening. Unfortunately only 11 2/3 X 17 x 9.  RM-40s along the short wall, in four feet from the end wall and about 7 feet apart  (in about 2 feet from the side walls). The long walls are lined with base cabinets  30 inches high topped with book shelves going up to within 3 feet of the ceiling. These are pretty much filled with books, CDs, and DVDs.  Floor is light weight concrete covered with carpet, walls and ceiling are plasterboard with one door and two windows (which ara covered by the bookshelves).  I listen to the RM-40s, nearfield sitting about 4 feet from the back wall. I  need to make some corrections. I seem to have a big spike at both 31.5 and at 80 cps which calls for some acoustic treatiment.  With the exception of the spikes, sound pressure readings at 1/3 octive intervals range from 57 1/2 to 59 up to 400cps. 500cps is 61, and 630cps is 63 1/2. Then the readings  in the range of 800 to 6,300cps are from 66 1/2 to 69. Readings in the 8K to 20K range  run from 62 to 64. The speakers sound too "bright" Mid range and treble controls on the speakers are at about  1:45 and 2:30.  Which of these would more likely reduce my 800 to 6,300 plateau? At present I have no acoustic treatments. Suggestions VERY welcome.

[Brian Cheney]

Typical "starter" situation for a small room.  Set the mid at 12 o'clock, the treble at 12:15, and undamp the PR to take care of the humps.  Very little putty needs to be removed, so go slowly.

[Sedona Sky Sound]

Hello PLMONROE,
11 feet is pretty tight. Have you tried putting the speakers on the long wall? You could have the speakers out in the room  few feet placed about 8-10 feet wide. Your listening position should be relatively close to the back wall to minimize rear reflection time (a concept that John Dunlavy was a big fan of). Having staggered books behind you or the speakers (or both) is OK since it makes a really good diffuser. Another side benefit to this design is that you will minimize the first room mode you are currently experiencing.    

I agree with Brian that your settings are currently too high for an undamped room. My room is relatively damped and my settings are just a little higher than what Brian recommends. I think John Casler mentioned that his room is pretty live so he has his turned way down.

For the high frequencies, make sure and do the "mirror test". While sitting in the sweet spot, look for the reflections of your tweeters in a mirror held against the wall by a friend. At each location that you can see the tweeter, you need some room treatment to break up or absorb the reflection (a wool rug works well).

For your lower frequency humps, you will need to determine if a bass trap or a helmholtz resonator is what you need. Look on the net for a Sabin calculator to figure out how much your room absorbs sound at each frequency. If your walls are already absorbing lots of bass frequencies, then a bass trap may make your room too dead.    

The other thing you can do is move your listening position to a null location in the room (the greatest null is directly in the center of the room). Things around you might be vibrating but in a null position you wil not hear these peaks (or they will be greatly reduced). I prefer correcting the problem but thought I would just throw this out.  

Best of luck.

Julian
www.sedonaskysound.com

[John Casler]

Hi Pl,

I think Julian nailed it.

I would certainly try setting the room up on the long wall if you can.

Place the speakers at least 8-9 feet apart with the rear of the speaker 1 foot off the front wall.

You can place your listening chair/sofa within 6-10 inches of the back wall as long as you have one or two 24x48x3 pyramid or wedge acoustic foam panels right behind your head.

These will pretty much dampen or absorb most of the major reflections and acoustic hash.  

Bass should be rather strong and you will have a soundstage to die for.

Julian's idea of staggering the books was exactly what I thought of earlier today when I saw your post.  It might look a little strange but it is a cheap diffuser.

I would also place two of the same size acoustic foam panels directly in front of you almost like a movie screen (at least for serious listening)

I would also try converging the RM40s directly on axis and take a peak at my "Sonic Director" tweak, I posted recently to help the midbass blending at nearfield.

I would also use Big B's suggestion of starting at 12 noon on the pots.

I have a feeling you will like the way this sounds and it will probably smooth out most of your other problems.

Now initially it will feel like the speakers are too far apart and way to close,   but wait until you have them converged and are sitting in the sweet spot.

If it is too boomy, move the couch out another 6" or more until the boom is gone.

You should, with this set up, have a center image that will totally deny reality.  You and all your friends will swear that when they/you are in the sweet spot that a center speaker is hidden behind the books or the acoustic foam directly in front of you.

I'll e-mail you privately with a tweak that will help you get lazer precision in the convergence.

For aesthetic purposes you might find tacking some heavy velvet over the acoustic foam is attractive or just the heavy velvet itself may be adequate over the books when you are facing it from the sweet seat.

Even if just for "shits and giggles"   as the brits say (don't they?) it could be an interesting set up.

If you can try it (I know it might be less pelaesing to the SO) let us know how it works for you.

[PLMONROE]

WOWWWW!   I ask a question and back come three responses from no less than  Big B, Julian, and John. How much more expert advice could one hope for? Brian, you know this whole #%&%^@*# mess is all your fault don't you?  Up untill a year ago I spent about 80% of my leisure time watching video in my home theater and 20% listening to music. All I wanted  was a couple of better speakers for my front left and rights and since the  RM-40s had swept the field at Vegas, I  thought I would give them a shot. I became so thoroughly seduced by their sound that now I seem to be spending ALL my time listening to music!  Along the way I got 4 626Rs from Brian and the the center from you  John to complete a 7.1 setup. But I still seem to keep coming back to music. Arggh!
However since I do still watch some video and (don't tell my wife)  have 25K or so investsed in the front projector setup, I am stuck with the present room layout.  Last night I adjusted the controls on the RM-40s  to 12:00 and 12:15 per Brians advice. This reduced my plateau by about half. Guess I am going to have to go down to 10:00 or so, something I would never have believed. Also Its obvious that I am going to have to look at some room treatments as well. John I have already employed your tweeks and they do wonders. Since I am stuck with my present room orientation what further suggestions might I consider  (short of moving the PJ to the basement)? Thanks.
Paul

[Horsehead]

Up untill a year ago I spent about 80% of my leisure time watching video in my home theater and 20% listening to music. All I wanted was a couple of better speakers for my front left and rights and since the RM-40s had swept the field at Vegas, I thought I would give them a shot. I became so thoroughly seduced by their sound that now I seem to be spending ALL my time listening to music!

How true!  My projector only seems to be getting fired up only a couple of times a month now.  The sound of the RM40s is truly enjoyable with no listening fatigue.  One thing must be said also, when the RM40s are required to do home theater- they kick a$$!  The same qualities that make them exceptional music speakers work just as well with movie soundtracks.  I've laughed at myself quite a bit doing some embarassing things during some intense movie soundtracks, like jumping up from my listening postion in a fighting stance when I thought someone had "entered" my room!      I wasn't   either!

[audiochef]

Your initial  placement seems too far apart which in my past experiments would tend to emphasise  brightness. Try moving about six inches closer together. You also didn't mention what tweets and caps your're using.
     Take alook at my pics on page 2. Very well balanced sound there.
     Good luck, I'm sure you'll find a happy medium.

     Stan

[flintstone]

I would move each speaker out from the rear wall another 12-18 inches and about 6 inches more away from the side walls. Face them straight ahead and then toe-in slowly until image snaps into place, to much toe-in can make for a brighter sound. Treat the other side wall so as to more match the wall with all the books, put a couple bass traps in the corners behind the speakers and you may need to add some treatment to the center of the wall behind your speakers as well as upper corner treatment. Once you get the room together, tune the speakers.

Dave

[John Casler]

Since I am stuck with my present room orientation what further suggestions might I consider (short of moving the PJ to the basement)? Thanks.
Paul

What are:

1) distances of RM40 from front and side walls
2) Listening distance from front of RM40 to your sweet seat
3) How far apart
4) What are the surfaces like on the right and left walls from speaker to listener
5) what is your rear wall like?
6) Are you using any Acoustic Treatment at all?
7) What is in each of the 4 corners?
8)What is the ceiling made of
9) What tweaks have you already tried?
10) How are you currently converged?
11) Is there any furniture in the listening area? What and where?
12) Where is the equipment?

That should keep you busy for a while  

[audiochef]

I need to express my appreciation for this lite hearted fun we are all enjoying through VMPS. It's really special to me. Wish more could see the light.  Very entertaining Horsehead.
          Stan