Bookshelf Speaker Boundary Problem

[GO-NAD!]

I originally posted this in the "Amps, Pre-Pro & Receiver" section (although the thread should've started here, I suppose) because I was thinking of getting an active crossover for my living room 2.1 system. But, after being informed that it probably wouldn't solve my boundary effects issues, I have to look at taking other measures.

Well, here's my system. Boy, those photos sure look grainy when they're compressed that much. So far, I've been able to keep my wife from putting more stuff on the shelves beside the speakers. As you can see, putting those speakers on stands will stand out like a really sore thumb. There's just no space for them. The other end of the room opens up to the hallway and the dining room.

I still have to build a cabinet for my components. It'll go directly opposite the present position, to where the end table currently resides. The subwoofer will stay where it is.

So, it boils down to the following options:

1) Buy or make wall-mount brackets for the speakers and mount them out on the side walls.

2) Put some acoustic panels behind the RC-10s. The space is about 16" x 32", but the treatment could only be about 3" thick max. Would that be of much benefit? I just don't want to go through the expense, time and effort to put something in there that won't make any practical difference.

3) Buy in-wall speakers. The ones I have in mind are the Axiom M-22 in-walls. They have a backer box already, so I wouldn't have to mess around with that. I'm thinking the dual woofers would do a better job of moving the air in such a large space. I could probably convince my wife that the expense is worthwhile, since I'll be freeing up the shelf to do whatever she wants with it.

There are two concerns with this option though.

These are the exterior walls, which are not insulated , as it's an older house, built of brick. Brick requires an air space so that any dampness, due to condensation, on the inside face of the brick can dry out. Makes it easy to run wires though . It gets pretty cold here in the winter - should I be concerned about the drivers getting quite cold? I should probably ask Axiom about that...

Plus, installing in-wall speakers would require that the tweeters be very high up the wall. I could build a wedge-shaped box frame to angle them down a bit.

Those M22's really appeal to me though...

4) Leave well enough alone. Maybe I'm just being anal in thinking that I need to do something to improve my SQ. I've looked at a lot of the photos of members systems and many of them have subwoofers in corners and floorstanders just a few inches from the back wall. They don't seem to complain much about SQ, due to speaker placement.

Any thoughts?

 

[jostenmeat]

I still have to build a cabinet for my components. It'll go directly opposite the present position, to where the end table currently resides. The subwoofer will stay where it is.

So, it boils down to the following options:

1) Buy or make wall-mount brackets for the speakers and mount them out on the side walls.

Sure. Have you played with the speakers further out, and with toe-in experimentation as well? I've heard some Ascends pretty far apart, and the imaging was excellent, as wall mounted.

2) Put some acoustic panels behind the RC-10s. The space is about 16" x 32", but the treatment could only be about 3" thick max. Would that be of much benefit? I just don't want to go through the expense, time and effort to put something in there that won't make any practical difference.

Not of significant benefit. The best places to treat first are the first reflections (usually/most likely sidewall, possibly rear wall, or perhaps ceiling) and corner trapping for bass (with the front wall getting the priority).

3) Buy in-wall speakers. The ones I have in mind are the Axiom M-22 in-walls. They have a backer box already, so I wouldn't have to mess around with that. I'm thinking the dual woofers would do a better job of moving the air in such a large space. I could probably convince my wife that the expense is worthwhile, since I'll be freeing up the shelf to do whatever she wants with it.

If willing to do bookshelves wall mounted, I'd vote for that over in-walls, for more performance per dollar.

4) Leave well enough alone. Maybe I'm just being anal in thinking that I need to do something to improve my SQ. I've looked at a lot of the photos of members systems and many of them have subwoofers in corners and floorstanders just a few inches from the back wall. They don't seem to complain much about SQ, due to speaker placement.

Any thoughts?

I wonder how much experimenting some of these people have done. I wonder how much experimentation you have done. I myself have found that even with entry level ~$200-300 bookshelves, that getting them a few feet, or more, from the front wall has great benefit. However, I completely understand that people don't want speakers way out in the usable living area. But, due to ergonomic/aesthetic issues, I still wonder if some people have even tried.


for a cheaper thing to try for now: some auralex mopads to decouple from the wood shelf top?

 

[GO-NAD!]

Sure. Have you played with the speakers further out, and with toe-in experimentation as well? I've heard some Ascends pretty far apart, and the imaging was excellent, as wall mounted.



Not of significant benefit. The best places to treat first are the first reflections (usually/most likely sidewall, possibly rear wall, or perhaps ceiling) and corner trapping for bass (with the front wall getting the priority).

If willing to do bookshelves wall mounted, I'd vote for that over in-walls, for more performance per dollar.

I wonder how much experimenting some of these people have done. I wonder how much experimentation you have done. I myself have found that even with entry level ~$200-300 bookshelves, that getting them a few feet, or more, from the front wall has great benefit. However, I completely understand that people don't want speakers way out in the usable living area. But, due to ergonomic/aesthetic issues, I still wonder if some people have even tried.

for a cheaper thing to try for now: some auralex mopads to decouple from the wood shelf top?

I would only get away with room treatment in the space behind the speakers. Anywhere else is a non-starter.

I had experimented with placement before I built the cabinets, while the speakers were on stands, but not after. Of course, they sounded better when pulled out from the back wall. If I take a shot at wall mounting, I'll have to do some experimenting with placement for that location - before I start drilling holes for brackets. Can you tell me how the auralex pads work with the speakers? Right now, I have just soft rubber feet under them.

 

[the grunt]

Looks like you are good at woodworking (nice room BTW) have you thought about making slide out shelves for them rather than using stands. You could keep them right were they are now when not using them or worried about critical listening. It would then be easy enough just to slide them out a foot or so to get them further off the front wall and out from the fireplace a bit. Might help and wouldn’t be in the way normally.

Similarly you could buy or make a swing out mounting bracket attached to either side of the fireplace allowing you to swing the speakers out into listening position or push them back above the cabinets for storage. This might get you more extension out into the room than slide out shelves.

If you did shelf mount them on the walls you could build a sound treatment to catch the first reflection of the wall right into the shelf and make it just look like part of the shelf.

I’m with jostenmeat in that I’d take wall mounted bookshelf over in-wall.

Plus, installing in-wall speakers would require that the tweeters be very high up the wall. I could build a wedge-shaped box frame to angle them down a bit.

I you went this route there’s no reason you can’t mount a speaker upside down to keep the tweeters lower. I’ve done it and didn’t notice any effect on the SQ.

More than happy to offer up any more weird ideas if I think of them.

Cheers,
Dean

 

[GO-NAD!]

Looks like you are good at woodworking (nice room BTW) have you thought about making slide out shelves for them rather than using stands. You could keep them right were they are now when not using them or worried about critical listening. It would then be easy enough just to slide them out a foot or so to get them further off the front wall and out from the fireplace a bit. Might help and wouldn’t be in the way normally.

Similarly you could buy or make a swing out mounting bracket attached to either side of the fireplace allowing you to swing the speakers out into listening position or push them back above the cabinets for storage. This might get you more extension out into the room than slide out shelves.

If you did shelf mount them on the walls you could build a sound treatment to catch the first reflection of the wall right into the shelf and make it just look like part of the shelf.

I’m with jostenmeat in that I’d take wall mounted bookshelf over in-wall.

I you went this route there’s no reason you can’t mount a speaker upside down to keep the tweeters lower. I’ve done it and didn’t notice any effect on the SQ.

More than happy to offer up any more weird ideas if I think of them.

Cheers,
Dean

Now you're talkin'!! The slide out shelf is a brilliant suggestion! Maybe even a telescopic bracket mounted to the wall. Ooooh...the gears in my head are turning now! I just need to come up with something rigid enough to support the weight and not to vibrate.

IF, I were to consider the in-walls, I'm not sure about puting them upside down. I would think that the mantle would deflect the high frequencies over the heads of anybody sitting down. Is that a possibility?

Thanks for the suggestions!

 

[the grunt]

IF, I were to consider the in-walls, I'm not sure about puting them upside down. I would think that the mantle would deflect the high frequencies over the heads of anybody sitting down. Is that a possibility?

As long as the tweeters have a direct line of sight to the listeners ears they will hear the direct sounds properly. The problem with the mantel will be the same thing as the walls if you mount them there which is the first reflection is going to be so close to the source it will cause worse comb filtering. The interference pattern will colour the sound of the speakers by reinforcing and canceling certain frequencies unless something is done to absorb or diffuse it.

Just remember in-wall speakers are still going to have boundary effect issues do to the proximity to the wall they are mounted on. So if your finding that a problem I don’t see in-wall being a good solution.

Now you're talkin'!! The slide out shelf is a brilliant suggestion! Maybe even a telescopic bracket mounted to the wall. Ooooh...the gears in my head are turning now! I just need to come up with something rigid enough to support the weight and not to vibrate.

I’m planning to something similar with my surround speakers but with sliding mounts. I prefer 5.1 with the surrounds farther back for games, but will likely use 7.1 with the surrounds right out from the seating for movies. Best thing I’ve come up with to avoid using another set of speakers is to mount them on a sliding bracket.

Cheers,
Dean