Surround Speaker Placement (AV-1RS vs AV-1) in Hardly Ideal Room

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mr7q

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I've been lurking about here for a bit, trying to suck up all the information around like a sponge, and have pretty much committed myself to getting a GR-Research system in the next month or so.  I'm going to start construction on a theater system in my apartment shortly.  The GR-Research speaker kits seem to be ideal, both because of the numerous positive reviews, as well as the fact I love building my own equipment.  Thankfully I have a friend who's quite the woodworker, and I'll take any excuse to fire up my Weller, so I don't see too many problems on the construction aspect.

However, actually figuring out how to place speakers in my most definitely non-ideal room is where I claim to have absolutely no experience.  Compounded with the fact that the cieling firing AV1-RS speakers aren't exactly traditional, so asking my normal circle of friends that are into speaker design and placement has had them confused as well (they're eager to see how this system turns out - Have to love being the guinea pig  :lol:).

As such, I've managed to mock up my living room using my fantastical graphic designer abilities (Note: I'm an EE).



The black box is the equipment rack, the grey the subwoofer, and the brown are AV-3 floorstanders and an AV-3S as a center on top of a 55" Mitsubishi CRT Rear Projector.  I like to sit on the couch.  The strange looking set of lines along the left wall is a rack with my bicycles mounted on it.  There's about 2' of space between the rack and the wall, but I'm guessing that fitting a AV-1RS in that nook would probably be a bad move.  That's pretty much set up there, and essentially locked in (no real other way to configure the room).  Finding ideal placement for the rears is where I'm starting to find where the fun begins.

I've gone through the different possible configurations and labeled them with letters.

Option #1:Using a 6.1 system, put RS speakers at locations A and C.  However, since I've got no experience with this, the problem is that the side-rear speakers (A), would be in line with the front of the couch.  In what I've picked up, ideal location  would be directly on axis with the listener.  I'm also not sure how having the AV-1RS so close to an open wall (left side position A) would affect the sound of the speaker.  That said, this would be my ideal solution, as it would mount the speakers up and out of the way, but I'd like to have a good sounding and balanced system first.

Option #2A: 6.1 System, but using AV-1 bookshelf speakers side firing on line with the listening position (Position B).  Use a AV-1RS in Position C.

Option #2B: 7.1 System, essentially the same as above.  Except instead of AV-1RS at position C, use two AV-1 bookshelves at Positions D.  This one makes me hesitant, as I can't imagine that pushing a speaker into the right position D would be anything close to ideal.

As such, I was hoping that there'd be someone here that might have some pointers as to which direction I should be looking.  I'm still a complete neophyte to this whole theater design thing, and am eager for any help that anyone can give. :scratch:

Thanks in advance!  I have a bad feeling this is going to be the start of another hobby that I'll be powerless to not sink money into. :cry:

MaxCast

What are the dimentions from tv to d and tv to b?
What are you going to drive this with?

bgewaudio

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Wow, that's quite the room you've got there.

You could use some inexpensive ceiling mount brackets for the rear surrounds, and I would side fire main surrounds left and right overhead at locations B, this way you can have all speaker in approximate vicinity with one another so you don't have to play around with too many channel level adjustments.

mr7q

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I'm at work, so I'll guesstimate as to the distances.  Basing on the width of the door being 36".

The far wall is somewhere around 12'-14'.

TV comes off the wall 2'.

TV to A seems to be about 9'
TV to B seems to be about 12'.
TV to C seems to be about 18'.
TV to D seems to be about 17' (probably a bit less since they'd be off the wall).

The receiver I'd be driving it with is currently up in the air.  Nothing super fancy.  Front runner seems to be a Yamaha HTR-5940, but still trying to figure that one out.  The relatively high sensitivities of the GR speakers seem to indicate that I don't need to throw THAT much power at them.

mr7q

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Wow, that's quite the room you've got there.

You could use some inexpensive ceiling mount brackets for the rear surrounds, and I would side fire main surrounds left and right overhead at locations B, this way you can have all speaker in approximate vicinity with one another so you don't have to play around with too many channel level adjustments.


If there's anything I excell at, it's making my own life difficult.  :lol:

I had my 6.1 system all planned out with bookshelves at B and then a rear at C (probably was going to purchase AV123s).  Then, I had the misfortune to stumble upon the GR-Research site after a coworker said, "Why don't you build your own speakers?" and found the concept of the upwards firing AV-1RS speakers.  Was intrigued enough to see if they'd work in the A positions, or if in fact the B/C/D standard firing speakers were the best arrangement for my room.

I just wish I had infinite time and money, and then I could try both configurations out, but sadly that's never the case.

TomS

I have 2 AV1-RS's on the rear sides and 2 in the back with 8' flat ceilings in a 13x19 room.  Fronts are Merlin TSM-MX's.  When properly placed at 16" the sound hitting the ceiling is quite diffuse, so I don't think a little bit of distance imbalance L/R to the listening position is going to hurt too much.  I would try to get the sides aligned F/R close to where you sit though.  Maybe use A-A and D-D or C.  Mine has the couch against the back wall instead of the middle like yours, and the sides are slightly in front of couch position (~4') with rears right above it/behind the couch 8' apart.  I experimented quite a bit with temporary placements (using 1 small nail to hold them up) before drilling final speaker wire/mounting bracket holes in the walls and found this was the best setup for mine.  They sound terrific and surround effects are downright scary seeming to come out of nowhere sometimes.  Having heard the AV1-RS's I'd have trouble going back to a direct radiated speaker like AV1 for surround/rears.  Perhaps you would for multichannel where you're more concerned with matching all around, but I don't use them for that at all.

On the receiver you might look at the Arcam AVR300 used which is coming down in price due to the new AVR350.  I have the Arcam AVP700/P1000 separates which are a great match for the Merlin/GR's setup.  I doubt I'm using much of the juice the P1000 can deliver in this small room so I suspect the AVR300 would have been just fine.  Very smooth overall with excellent dynamics.  It's also quite low on the typical receiver mid-hf harshness which suits me fine.

Danny Richie

TomS gave a pretty good account for the sound of the A/V-1RS. They are ideal for the surround application. The defuse, non-localized sound field that they produce is just incredible.

I'd go with a pair of them in locations B and mount them as fair back as you can. Then use one in location C.

I think the best bargain going on receivers has to be the all digital Panasonic (I think the latest model is a XR55) . It is a pretty good sounding receiver for very little money.

mr7q

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The problem with sticking the AV-1RS at the location B is on the left side, it'd essentially be back in a channel between the wall and the bicycle rack.  Measuring it last night, It looked like I could get only a couple inches on each side if I stuck a speaker back there (it's about a 3' wall right there between where I have A and B marked on the left side).  Reading everything I could get my hands on from this site, it seemed like 24" per side was optimal for the sound diffusion...  Since placing the RS speaker at position B on the left side, it'd essentially be in an alcove, which by my logic would focus the sound quite a bit, and produce results the opposite of what I was looking for in a rear channel application (of course, I may be horribly wrong, since I'm a complete newbie to this entire thing).

TomS, from the sounds of it, you've got a similar set up to the A-C speaker locations in that your main sides are in front of the listening position.  I measured it last night and it came to around 3' from where my head would be to the center of the speaker point.  However, seeing as you seem to be running 7 channels instead of my 6 (again, the 24" offset limits what I can do on my back wall, and I doubt mounting anything to door on the closet would probably not work so well), I'm hoping the difference wouldn't be something I couldn't compensate for with the amplifier.  Of course, now I'm getting the "bright idea" of seeing if it would be possible to modify a AV-3S in an upward firing mode to serve as the rear-center at position C with a modified network from an AV-1RS.  But, then again, I should probably not try to get too crazy in a subject I'm still learning the basics of.  Curse my mad scientist play-with-it-until-you-know-what-the-heck-you're-doing instincts.

And I wish I could afford that AVR300.  Sadly, it seems to be a couple hundred more dollars than what I was hoping to spend on the entire system...  That said, the receiver will probably be the first thing I replace as I move on down the road.

All, many thanks for the responses so far!  You've been a tremendous help so far.

Danny Richie

Okay, I have an idea.

This discussion and application is really leading towards something I have had on the drawing board for a while. I have made some basic test and have taken measurements of various drivers for this application, and have come to a point where it might be time to start cutting some wood and building a prototype.

Here's the idea. I want a free standing or floor standing omni-directional speaker design. These can be primarily used as surround channel speakers but could be used as main speakers as well.

I tested up firing a lot of different woofers and took measurements at right angles to the woofer, and some vertical off axis ones as well. I measured different 3", 4", and 5" woofers. With some I added extensions to their Aluminum phase plugs that flared out like an inverted umbrella. I used curvilinear shaped woofer cones and filled them with plaster to make them solid. It was interesting.

The smaller the woofer the better the off axis response. But the smaller woofers just didn't have enough power handling. The better sounding one that I tested was the FR-125. But it just won't take any power. 30 watts of full range power and it was maxed out. It had low sensitivity and little bass output too.

The better choice was our M-130. It had a smooth roll off in the top end and decent off axis response. But the bigger the woofer, the lower the crossover point has to be. It looks like 2.5kHz or so is as high as it is going to play. I may have to cross it over in the 1.5kHz to 2kHz range to make it work. This is a pretty low crossover point for most tweeters. I may have to try a Neo 3 pdr first as it can easily be crossed this low.

Keep in mind that without the reinforcement and gain from walls and ceilings it has to do it all in free space.

Next was trying to make a tweeter work. With nothing to reflect off of, like the A/V-1Rs design has, it is pretty much impossible to get high frequency extension with an up firing tweeter. The more I tested it though the more I realized that the tweeter doesn't have to be omni-direction. As frequency increases it is going to play into 2 pie space anyway. It can be aimed to a more or less off axis angle and the top end output level adjusted in that way.

My research has lead me down a path of conclusions similar to those of Siegfried Linkwitz. His omni-direction design can be seen here:

http://www.linkwitzlab.com/Pluto/intro.htm

I am considering up firing one M-130 woofer in a floor standing design only 7.5" square and running it to the floor. It can be ported near the floor and tuned to hit -3db down points in the 55Hz range. The height will be in the 36" to 38" range.

I wonder if I can make it an 8 sided box and still keep it easy to build? I mean 8 sides plus a top and a bottom. This will give it a rounder look. It can have a heavy or wider base to it with floor spikes in the bottom.

I still need to do some experimenting with tweeter locations too.

What do you guys think?

Loftprojection

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Wild!  :o  But very interesting!   :thumb:

MaxCast

would a tube wrapped in veneer work?

TomS

Wow Danny, you need to get more sleep.... :o

I agree with the sonotube sort of idea.  They are cheap and easy to work with.  Maybe in smaller sizes WAF would be better (I have a big SVS sub which is NOT)

Danny Richie

The Sonotube idea works great for the woofer, but my biggest problem is where to put the tweeter.

Everything that I have tried above the woofer has had some effect on the woofers response. If the enclosure is a narrow rectangular shape then I could locate the tweeter on one of the sides right below the woofer. I have to see what the time arrival effects are though.

I'll keep working with it.

MaxCast

Find a tennis ball and mount it so it can rotate.  Maybe velcro.

klh

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Having a floor standing surround speaker that added air without being directional would be great for those who would have difficulty with wall mounting the AV-1RS speakers. I'm sure you'd do very well if you could design a set that would mate well with the OB-7s and OB-5s. I saw those speakers on his website a couple weeks ago and thought the design was very interesting, but that they were a bit ugly. If you could take his idea but come up with something that uses your drivers and actually looks beautiful, well, that would be great.

The one exception to the ugly factor would be this project:





« Last Edit: 18 Aug 2006, 08:14 pm by klh »

Brucemck

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Danny, it's a great idea.  I liked the Linkwitz approach the first time I saw it, and it'd be a great complement to the wall mounted surrounds (which I own and love and recommend.) 

Your practical solutions to placing good surrounds in real world rooms is a welcome addition to the craft!

Danny Richie


TomS

Sorry to resurrect this redirected thread, but I finally got around to taking pix of my AV1-RS's mounted in my home theater room (mentioned above).  After exchanging messages with Danny a while back, I probably have an ideal situation for them as the viewing seat is backed up to the rear wall and the room is a nice clean rectangle (13x19x8 with flat ceiling).  They sound terrific about 16 inches from the ceiling.  I just painted the boxes wall color to blend in.

Here are the 2 AV1-RS on sides and 2 AV1-RS on rear wall above viewing position:






Arcam AVP700/P1000/DV79, JVC D-ILA 1080p, Merlin TSM-MX's (gloss Ruby Red), ACI Titan II subs, and the "red rocket" dog, Riley:






Danny Richie

Wow, those look great Tom. Thanks for posting the pics and the feedback.

TomS

I look forward to stopping by to say hello at RMAF.  See you there.