Active Cross-overs

[GO-NAD!]

I'm on a new quest now. I'll be constructing backerboxes for my in-ceilling speakers when I do some other work in the attic (kill two birds with one stone). Going 7.1 in the rec room has to wait until I renovate down there.

Here's my quest. I want to improve the SQ of my living room stereo system. My bookshelf speakers (Energy RC-10s) are in fact, on a shelf. and due to WAF, that is where they will stay. They are also powered by my C-372. That leads to two problems. 1) They are too close to the wall and I'm not happy with the bass response as a result. 2) The amp has a lot of ponies I can't really take advantage of, because it's just too much to ask of a single 5-and-a-half-inch woofer.

Therefore, I'm thinking about buying a CX2310, hoping that it will mitigate, if not actually solve the two problems. This is how I envision the results:

1) Cutting off the bass frequencies below 80 Hz will even out the bass response (bass trapping is a non-starter, due to aforementioned WAF). I realize that the room mode issues can extend up to higher frequencies, but I'm guessing that the lowest frequencies are the worst culprits?

2) By not asking the speakers to reproduce the lowest frequencies, I'll reduce the stress on the drivers and get cleaner output at higher volumes.

So, for those of you with knowledge of active cross-overs, do you think it's a worthwhile investment of money and effort to utilize an active cross-over, such as the CX2310? If the concensus is yes, I'm gonna have some questions about installation. I've read the manual for the CX2310 and it isn't perfectly clear to me...

I will, as promised several times, post photos of my setup. I just need to build a component stand first...

 

[TLS Guy]

I'm on a new quest now. I'll be constructing backerboxes for my in-ceilling speakers when I do some other work in the attic (kill two birds with one stone). Going 7.1 in the rec room has to wait until I renovate down there.

Here's my quest. I want to improve the SQ of my living room stereo system. My bookshelf speakers (Energy RC-10s) are in fact, on a shelf. and due to WAF, that is where they will stay. They are also powered by my C-372. That leads to two problems. 1) They are too close to the wall and I'm not happy with the bass response as a result. 2) The amp has a lot of ponies I can't really take advantage of, because it's just too much to ask of a single 5-and-a-half-inch woofer.

Therefore, I'm thinking about buying a CX2310, hoping that it will mitigate, if not actually solve the two problems. This is how I envision the results:

1) Cutting off the bass frequencies below 80 Hz will even out the bass response (bass trapping is a non-starter, due to aforementioned WAF). I realize that the room mode issues can extend up to higher frequencies, but I'm guessing that the lowest frequencies are the worst culprits?

2) By not asking the speakers to reproduce the lowest frequencies, I'll reduce the stress on the drivers and get cleaner output at higher volumes.

So, for those of you with knowledge of active cross-overs, do you think it's a worthwhile investment of money and effort to utilize an active cross-over, such as the CX2310? If the concensus is yes, I'm gonna have some questions about installation. I've read the manual for the CX2310 and it isn't perfectly clear to me...

I will, as promised several times, post photos of my setup. I just need to build a component stand first...

I very much doubt that what you propose will solve your problem. Your difficulty with your speaker placement will be between 80 Hz and 600 Hz principally.

Here are the reasons: - most speakers are voiced and corrected to be away from boundaries. When you put most commercial speakers near a boundary, the frequencies I mentioned become over emphasised, and worse the immediate boundaries cause peaks and nulls from the proximity of the reflected waves.

If you have to have your speakers stay where they are, then a custom build and custom crossover is your only route to better sound. In other words you have to design and voice a speaker for that location.

 

[GO-NAD!]

If you have to have your speakers stay where they are, then a custom build and custom crossover is your only route to better sound. In other words you have to design and voice a speaker for that location.

Well, I'm glad I asked. I don't think that's going to happen

If I built/bought mounting brackets and attached them to side walls (which are 11 feet apart), a couple of feet from the back wall, might I be any further ahead? I have doubts about that - the speakers would be quite close to the side walls and very far apart.

 

[ski2xblack]

all hope is not lost

You could always try to find your wife's weakness and indulge it. My woman's weakness is Dave freakin Matthews. We get a new disc like every week in the mail, and I'm soon to be off to have my hearing shattered in the front row at the Gorge for three straight nights.

Anyway, I used her fondness for live DMB to get somewhat of an allowance in the form of reduced WAF. Once she got a taste of what I had in mind, the dam broke and she allowed me to do pretty much whatever I wanted. (Of course, I may be one of the lucky ones. Her father has been a professional musician for decades, and a gear-head who has about $100K of audio equipment throughout his home. So perhaps extravagant audio is not a big shocker for her, given her upbringing. This may also indicate to you dads to prime the future generations by getting them accustomed to great sound.)

To the OP: getting those speakers out of the shelves should help, if you can sell the wifie on the idea. It should be much easier to deal with one boundary (side wall) than the bass-trashing and midrange-garbling effects of shelf placement. Good luck!

 

[GO-NAD!]

You could always try to find your wife's weakness and indulge it. My woman's weakness is Dave freakin Matthews. We get a new disc like every week in the mail, and I'm soon to be off to have my hearing shattered in the front row at the Gorge for three straight nights.

Anyway, I used her fondness for live DMB to get somewhat of an allowance in the form of reduced WAF. Once she got a taste of what I had in mind, the dam broke and she allowed me to do pretty much whatever I wanted. (Of course, I may be one of the lucky ones. Her father has been a professional musician for decades, and a gear-head who has about $100K of audio equipment throughout his home. So perhaps extravagant audio is not a big shocker for her, given her upbringing. This may also indicate to you dads to prime the future generations by getting them accustomed to great sound.)

To the OP: getting those speakers out of the shelves should help, if you can sell the wifie on the idea. It should be much easier to deal with one boundary (side wall) than the bass-trashing and midrange-garbling effects of shelf placement. Good luck!

I'm under no illusions about wearing her down much.

But yeah, I was thinking that I could get some improvement by only having side wall issues, rather than back wall issues. The RC-10s have threaded inserts, so a wall bracket arrangement is something to consider. I was wondering though - the speakers would have to be mounted higher than they are now, so would angling them down a bit compensate for the height change. Or am I just going to be trading my present SQ problems for others?

 

[highfigh]

You could always try to find your wife's weakness and indulge it. My woman's weakness is Dave freakin Matthews. We get a new disc like every week in the mail, and I'm soon to be off to have my hearing shattered in the front row at the Gorge for three straight nights.

I always wondered what his middle name was.

Take ear plugs. Get them at a music store and look for the ones that don't carve holes in the frequency response. They're not cheap but they can save your ears without making everything sound as if you stuffed sheep in there.

Hey- it works but they have to be very small.

 

[ski2xblack]

Or am I just going to be trading my present SQ problems for others?

It's always a comrpomise somewhere, unless your living room is a perfect replica of your favorite venue and your favorite band stops by to perform. But I think you're on the right track by getting the speakers off the shelf and into the room, as that should involve fewer compromises. I assume you could experiment with speaker placement without actually installing wall mounts, to see if it is worth pursuing. Since you are using a C372 I assume this is limited to 2 channel. You are not worried about the height issue due to center channel placement are you? Widening the distance between mains will necessitate experiments with toe-in (in addition to aiming them down if mounted up high) to maintain central image integrity, and also to address side wall early reflections (some strategicly placed art could help this too). Moving them from the back wall should improve image depth, which would compensate for the loss of depth typically experienced by widening their position. (Wider speaker placement equals bigger sweet spot, often at the expense of image depth.) Spend time experimenting and let us know what you come up with.

As an aside, I also have a C372 used to power some older M&K monitors, and I've used them both with and without an active crossover. While the crossover did allow for better devotion of amp power and added margin of safety for the drivers, the only time this was ever an issue was during ridiculously loud listening sessions. If you find yourself overdriving your Energy's, an active crossover would certainly be warranted. If, on the other hand, you are experiencing shelf-boom, simply moving the speakers off the shelf would fix the issue. (Without boundary reinforcement, you may be inclined to turn it up louder, in which case you would may need the crossover after all. I say work with what you got first, to wring the most out of it, before adding components.)

 

[ski2xblack]

I always wondered what his middle name was.

Take ear plugs. Get them at a music store and look for the ones that don't carve holes in the frequency response. They're not cheap but they can save your ears without making everything sound as if you stuffed sheep in there.

Hey- it works but they have to be very small.

Got 'em already. Now I think I may be able to withstand those incessant trumpet driven rocked out climaxes which permeate his shows and sound awfully repetitive after a while (kind of like Mike Houser guitar solos did).

To all you DMB fans, don't get me wrong. For a guy who's songs are all in the same key, he's pretty good.

 

[lsiberian]

I'm under no illusions about wearing her down much.

But yeah, I was thinking that I could get some improvement by only having side wall issues, rather than back wall issues. The RC-10s have threaded inserts, so a wall bracket arrangement is something to consider. I was wondering though - the speakers would have to be mounted higher than they are now, so would angling them down a bit compensate for the height change. Or am I just going to be trading my present SQ problems for others?

Why not go all in ceiling then? Better than having junk sound due to placement. I know it's not ideal, but it's something.

I personally will never use in ceiling speakers, but My wife knows my obsession and let's me enjoy it.

Not sure why your wife is so against speakers in an entertainment area. You can get some really nice speakers that look good and don't take away from aesthetics too. I wouldn't have speakers or a sound system if it came to that.

I think an EQ can help, but only so much. Boundary effects are nasty. Our Sunday School teacher's home setup is the painful demonstration of this when we hear stuff at his house.

 

[GO-NAD!]

Why not go all in ceiling then? Better than having junk sound due to placement. I know it's not ideal, but it's something.

I personally will never use in ceiling speakers, but My wife knows my obsession and let's me enjoy it.

Not sure why your wife is so against speakers in an entertainment area. You can get some really nice speakers that look good and don't take away from aesthetics too. I wouldn't have speakers or a sound system if it came to that.

I think an EQ can help, but only so much. Boundary effects are nasty. Our Sunday School teacher's home setup is the painful demonstration of this when we hear stuff at his house.

The thought of going in-ceilling or in-wall has crossed my mind as well, in-wall preferably. I think in-ceilling would really restrict the listening position to a very small area. That's for future consideration.

My wife is not against speakers - she's against speakers "stuck out in the middle of the room". And, in our living room it really would be awkward. I tried to post a couple of photos to indicate my placement conundrum, but I don't know how to reduce the file size of the photos, so that they could be attached.

 

[GO-NAD!]

It's always a comrpomise somewhere, unless your living room is a perfect replica of your favorite venue and your favorite band stops by to perform. But I think you're on the right track by getting the speakers off the shelf and into the room, as that should involve fewer compromises. I assume you could experiment with speaker placement without actually installing wall mounts, to see if it is worth pursuing. Since you are using a C372 I assume this is limited to 2 channel. You are not worried about the height issue due to center channel placement are you? Widening the distance between mains will necessitate experiments with toe-in (in addition to aiming them down if mounted up high) to maintain central image integrity, and also to address side wall early reflections (some strategicly placed art could help this too). Moving them from the back wall should improve image depth, which would compensate for the loss of depth typically experienced by widening their position. (Wider speaker placement equals bigger sweet spot, often at the expense of image depth.) Spend time experimenting and let us know what you come up with.

As an aside, I also have a C372 used to power some older M&K monitors, and I've used them both with and without an active crossover. While the crossover did allow for better devotion of amp power and added margin of safety for the drivers, the only time this was ever an issue was during ridiculously loud listening sessions. If you find yourself overdriving your Energy's, an active crossover would certainly be warranted. If, on the other hand, you are experiencing shelf-boom, simply moving the speakers off the shelf would fix the issue. (Without boundary reinforcement, you may be inclined to turn it up louder, in which case you would may need the crossover after all. I say work with what you got first, to wring the most out of it, before adding components.)

This is a 2.1 arrangement. I have the sub turned down more than I'd like, due to the bass issues I have from the speaker placement. I like to get them off the shelf but I don't have space for stands.

 

[TLS Guy]

The thought of going in-ceilling or in-wall has crossed my mind as well, in-wall preferably. I think in-ceilling would really restrict the listening position to a very small area. That's for future consideration.

My wife is not against speakers - she's against speakers "stuck out in the middle of the room". And, in our living room it really would be awkward. I tried to post a couple of photos to indicate my placement conundrum, but I don't know how to reduce the file size of the photos, so that they could be attached.

It would really be helpful to have a pictures of your living room and set up.

This is how you can easily compress pictures to post on the web. Open the photo in Microsoft office picture manager. Click on edit picture. Click on compress pictures. Under the heading compress for, select the circle against web pages. Then click OK. Now click save as, and save in another file so you don't over write your original picture. That is the easiest way I know how to do it.

Off all the solutions I have heard, in walls sounds as if it may be your best option. I would hate watching TV or listening to music via ceiling speakers. What a dreadful thought?

If you have a basement or bonus room, that might be your best solution for dedicated viewing or music listening. I was relegated to the basement for three houses. But in this house, I have a room with views!

We have had sound systems in living areas, but I have designed them for the purpose, and they have been very successful against the odds.

These corner speakers were in our last home, in the main living room.

They were inspired by Gilbert Briggs famous Airedale speakers.

My speakers though very different, worked very well in that difficult location.
The corners augmented the bass of the KEF B 139s well, not a bass shy driver in any event, and no sub was required. Imaging and perspective were surprisingly good. I really enjoyed my music fireside! We all used that system a lot. The new owners of that home certainly wanted those speakers.

The "works" could be totally hidden by closing a door.

In one of the main living areas of this home, again there had to be compromise and this ended up being the solution.

Since Raymond Cooke founder of KEF was GAB's protege, and I have always held the KEF B 139 driver in high regard, the appearance was to suggest one of Raymond's early designs form the early 60s, the KEF Concord.

The corner speaker and these new ones have the same driver complement except for the tweeter, but the crossovers are very different, because of location. with the loss of the corner location, gentle supplementation by two subs has been required.

So for WAF factor accommodation, the DIY builder and designer can pull a lot of tricks from the hat. This is another good reason for becoming a DIY builder.

 

[skers_54]

Have you thought of placing some custom acoustic treatments inside the shelf? I remember an earlier thread where Chris suggested using foam and rockwool to dampen a cabinet a subwoofer was placed in. Obviously, moving the speakers would be a better solution. I don't know how effective this method would be since the peaks and nulls are probably large, but it might be worth consideration given your tight WAF restrictions.

 

[GO-NAD!]

Have you thought of placing some custom acoustic treatments inside the shelf? I remember an earlier thread where Chris suggested using foam and rockwool to dampen a cabinet a subwoofer was placed in. Obviously, moving the speakers would be a better solution. I don't know how effective this method would be since the peaks and nulls are probably large, but it might be worth consideration given your tight WAF restrictions.

That also occured to me, but from what I've read about it, you need a LOT of material to make any practical difference. There is only six inches between the back of each speaker and the wall. That's with the front of the speaker at the front edge of the shelf. So, there isn't much room behind it for acoustic treatment. Sigh...

 

[GO-NAD!]

It would really be helpful to have a pictures of your living room and set up.

This is how you can easily compress pictures to post on the web. Open the photo in Microsoft office picture manager. Click on edit picture. Click on compress pictures. Under the heading compress for, select the circle against web pages. Then click OK. Now click save as, and save in another file so you don't over write your original picture. That is the easiest way I know how to do it.

Off all the solutions I have heard, in walls sounds as if it may be your best option. I would hate watching TV or listening to music via ceiling speakers. What a dreadful thought?

If you have a basement or bonus room, that might be your best solution for dedicated viewing or music listening. I was relegated to the basement for three houses.
We have had sound systems in living areas, but I have designed them for the purpose, and they have been very successful against the odds.


So for WAF factor accommodation, the DIY builder and designer can pull a lot of tricks from the hat. This is another good reason for becoming a DIY builder.

I will get some photos up when I get a chance (I'm at work right now). I have a fireplace in my living room, similar to your last home. I used to have my Monitor 9's on either side and there was room to keep them well away from the walls. But, I few months ago, I installed built-in cabinets on each side of the fireplace, going right to the side walls. There was no more room for floorstanders, so I went with the bookshelf speakers.

I really wish I'd thought through incorporating speakers into the design of the cabinets before I built them. It could've been so much simpler. I noticed on Axiom's website recently, that they have a version of the M60 for installing in cabinetry! That could've been an option worth exploring.

I'm mulling over the in-wall route right now. The big problem with that option is that they would have to be quite high on the wall, because of the cabinetry. The tweeters would be about 6 feet from the floor! I don't know if a shallow, wedge-shaped enclosure, fastened to the wall in order to point the tweeters down a bit would work. Any opinions on that?

 

[gs222]

Not ideal but.....

Have you tried using the port plugs that came with your RC-10's?

 

[GO-NAD!]

Have tried using the port plugs that came with your RC-10's?

I don't have the port plugs. The speakers were display models that I bought "as is".

 

[gs222]

I don't have the port plugs. The speakers were display models that I bought "as is".

I'm Dartmouth NS. I have RC-10's packed up in a box and I'm sure I have the port plugs. I'd be willing to loan them to you if want to see if that will help.

Send me an email at:
gshort at boyneclarke dot ca

 

[lsiberian]

Have you thought of placing some custom acoustic treatments inside the shelf? I remember an earlier thread where Chris suggested using foam and rockwool to dampen a cabinet a subwoofer was placed in. Obviously, moving the speakers would be a better solution. I don't know how effective this method would be since the peaks and nulls are probably large, but it might be worth consideration given your tight WAF restrictions.

I think it would help, but you'll still want to design it for that little spot.

I also remind you Chris is a perfectionist when it comes to response. It's good for helping us make better speakers, but sometimes things can become impractical. This is where a good engineer makes a tradeoff.

 

[GO-NAD!]

Figured out the photo thing!

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.
(gs222, thanks for the offer of the port plugs, but I don't think they'll be helpful in this location. I appreciate it though).

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, as mentioned before, 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?