Khanspires for behind AT screen?

[Bigdaddy]

Hi everyone, long time (sort of) viewer, first time poster. Great forum!!!

I've done the obligatory searching and think I've found what I want but I would like everyone's opinions.

I am currently building a 14'6" x 23'6" x 7'8" dedicated home theater. Double studs on interior walls, single studs over exterior walls (poured concrete) Double 5/8" drywall with green glue on ceilings and interior walls. Ceiling will have isolation clips also. Carpeted floor, two row seating, second on a 8"ish riser. Have plans for acoustic panels as needed as well as bass traps.

Equipment - is or will be Panasonic 1080p PJ with HTB anamorphic lens, Seymour AT (curved?) screen (120"ish 2.35:1), Onkyo TX-SR875 (140wpc), Sony PS3, Direct TV HD DVR, probably some sort of bass management also (SMS-1?)

I have two 15" TC-2000s that will go in large ported boxes (320l) and will be tuned to 14 hz or so. These will be driven by one each EP2500 - not purchased yet.

I will be building the LCRs exactly the same, the rear of the cabinet needs to be within 12" from the front wall, less would be better. It will be within 6" of the screen.

This is 100% HT, no two channel. I am willing to build around HT and will accept the compromises with music.

Dynamics are most important to me, I want to take advantage of the new DTs and Dolby lossless formats. I tend to like clean speakers with good high end, not overly bright. Everyone says that though, don't they?

Budget - I can go for maybe 2k for the 7.0 system, not including the subs, they are paid for. This needs to include the other 4 small wall mounted surrounds which will be the subject of my next post.

WAF - no issues, this is my room (and the LCRs are hidden)

Size - not an issue.

WWing skills - I am a somewhat accomplished woodworker with a decent shop. None of the speaker cabinets I've seen intimidate me in the least, although I don't want to build something fancy that won't be seen unless there are sonic benefits.

Questions:

Is the Khanspire the right choice?
Due to the loss of highs through the AT screen, can the tweeters handle some EQ boost to help out? The receiver has the Audyssey EQ system which I think works well with high frequencies.


I like the statements but am unsure about the transmission line mids being so close to the wall (which will be treated with OC703(or 705?)

I also like the maxx speakers, the 3way Daytons, just about everything.

I have no desire to reinvent the wheel, I want to use an existing design unless someone is willing to handle the design portion and the consensus is that a new design is needed.

Let me know what you think.

Thanks in advance.

Phil

[---k---]

I think you are correct, the Statements wouldn't be the right choice. Between being that close to the back wall and then the screen, I think the magic of the open back will be lost.

Of the other projects here, I think the Khans would be the best, but I am biased. If size is no object, I think the Khans will be better than the standard LineUp Maxx. I bases this primarily on the woofer. I believe the Khans are also a hair cheaper. And, if you're willing to spend on the Khans or the LineUps Maxx, then I wouldn't even consider the less expensive speakers suchas the RS TMWW or NatP.

The only other project I would suggest you consider is Jon's Modula Neo CC. I hear that these are pretty special and designed to be pretty close to the wall. They will be a bit more limited on the total spl and bass when compared to the larger designs, but likely not a real issue. They are quite pricey though (I think the BOM can be tamed, but don't let Jon see you doing it! )

My Khans currently have the back of the speaker about 10" from the wall and sound good. With the speakers being 14" deep, that puts the front about 24" from the back wall. I've moved them around a bit, and I don't remember them being too chesty when back more.

All the projects are going to suffer the same from tweeter attenuation and I believe some comb filtering. CJD can probably give better advice in this area, since he has speakers behind a screen (curved even).

[Bigdaddy]

OK - I'm committed to the Khanspires. I looked at the Modula's but would rather have a three way design.

I've heard a lot about the comb filtering on these forums but how dramatic is the problem? The AT screen people only refer to the frequency response change of their fabric, not this phenomenon. Will the tweeter handle some EQ to compensate or will this not work (it sounds as if I'll have to live with it based on my AT screen choice.

Phil

[dumaresq]

Since you are not going to be playing 2 channel audio you have no need for something as big as the Khanspires. Your subs will take care of all that you could easily build 5 (or 7) of one of the lineup series. I am not suggesting you shouldn't build something as big as the Khanspires... just that you don't "need" to it will save you some money and you can have 5 (or 7) identical speakers.

[cjd]

What AT screen? The SeymourAV or SMX material is about the only AT screen material I'd consider. It'll add 2-3dB of droop but if you use a receiver or pre-pro with any kind of EQ you can fix that perfectly.

The placement sounds ideal for the Khans, too.

And, I have found that the 3-ways I built for behind my screen don't quite have the oomph I want sometimes - that's dual RS180's for woofage. So, I do not agree at all with the statement that there is no need for something as big as the Khans. Besides, they're not big!

C

[Bigdaddy]

What AT screen? The SeymourAV or SMX material is about the only AT screen material I'd consider. It'll add 2-3dB of droop but if you use a receiver or pre-pro with any kind of EQ you can fix that perfectly.

I was looking at the Seymour AT material, I didn't think you could get the SMX fabric alone, only on a screen.

The placement sounds ideal for the Khans, too.

And, I have found that the 3-ways I built for behind my screen don't quite have the oomph I want sometimes - that's dual RS180's for woofage. So, I do not agree at all with the statement that there is no need for something as big as the Khans. Besides, they're not big!

C

I need a lot of oomph - the Khans are the way I want to go, I love overkill.


Can the size of the box be changed? I'd like to make is a bit taller, keep the front the same and lose some of the depth.

For that matter, can the Khans be easily modified for in wall use? I know there would be some x-over changes that are way beyond me but that solves a lot of my issues.

Phil

[cjd]

SMX and SeymourAV are very very similar materials - only Seymour if you're doing the screen yourself, yeah. Good stuff. It's what I used.

Box size can be changed some, but you gotta be careful not to get to a square build and not to get the rear wall too close. Driver layout should remain the same on the baffle, and width/edge treatment should be the same. You could always add a little height and put a "crossover box" under.

In-wall tweaks, I can probably work up a crossover based on simulated data - close but not exact. The RS28A would be out for sensitivity reasons I think (too low). Would be a new crossover though, not really a tweak.

C

[Dennis H]

Seymour if you're doing the screen yourself, yeah. Good stuff. It's what I used.

Chris, did you rotate the material a bit on the frame to help with moire problems?

[---k---]

I need a lot of oomph - the Khans are the way I want to go, I love overkill.

Can the size of the box be changed? I'd like to make is a bit taller, keep the front the same and lose some of the depth.

Phil

I used to think bookshelves with a sub was the same as big 3-ways. Not anymore. There is a big difference between using 2-RS225 for 80hz - 350hz and straining 1 or 2 RS180s in this region.

As for the size, yes you can reduce the depth and increase the height, but not much. I told this to someone else somewhere, but the problem is the space behind the mids. There is just 5.5" back there. I think that 4" is the least I would want to narrow that up to. So, if you line it with 1" of foam, then you got 2" of clear space to connect the top and bottom woofer.

I would think the best you could do is: 62"Hx11Wx13"D

[cjd]

Chris, did you rotate the material a bit on the frame to help with moire problems?

Yup. I think it ended up being 12.5 degrees. I opted to go for only 3 yards of screen material for a ~8' wide screen. HUGE pain to stretch to the BACK of a curved screen. I'm not sure I'd ever want to do what I tried here again.

If you go too shallow what I'd recommend is simply going full depth on the mid chamber and separate compartments for each RS225.

C

[Dennis H]

Getting off topic but I wonder if you even need to stretch the material around to the back. It's fiberglass so I'd think staples on the front side should hold pretty well. Then just wrap some molding (streamline door/base trim?) with black fabric and nail it to the front to cover the staples and the edge of the screen material.

[cjd]

No no, I have a velvet wrapped frame with the material stapled to the back of it. I won't bother trying to explain my line of thinking, though I will say getting a smooth curve is vital - so, what I did wasn't entirely out of line. But were I to try again, I have better ideas. Maybe.

C

[dumaresq]

I wasn't saying there was no reason to build something bigger, just that it wasn't needed... I have 16 cubic foot sub tuned to 14.5 and I am building statements for a room that is used 90% of the time for HT... I totally get the overkill option

[Bigdaddy]

Size matters

Size isn't a big issue with what I need, the LCRs will be behind an AT screen and there is enough room for just about anything. I will have two subs so I don't think I need to go really low with the mains.

On the other hand, I don't think bookshelf speakers can handle the headroom that I need.

I'm modeling up the boxes so I can make them work best for my situation, as I understand it, I want about 50l for each woofer, 15l for the mids and the tweeters don't care. I will be keeping the width of the front baffle as small as I can (11 1/4") in width and I will be increasing the height of the speaker to save some depth. I'm not going to get crazy. I think I could do an odd shaped box and really decrease the depth but I think this will hurt my performance by being too close to close to the wall.

Am i correct in the above numbers?

Thanks

Phil

[Bigdaddy]

In-wall Khans

OK - sorry to change midstream, I have my mind made up about the Khans, however, I keep coming back to the in/on wall options. I know the crossover would have to be changed, but how significant is that? Can someone (subtle hint) just change things based on modeling or is it a "start from scratch" thing?

I have a depth issue (3 1/2") in the wall that the speakers would be mounted so they would have to protrude from the wall or I could add false depth to it.

Let me know what you think.

Thanks

Phil

[cjd]

That much in-wall would require more than just a crossover redesign, i'm not sure if the RS225's would like being that close to the rear-wall of the box. My in-walls are 8.5" deep using the RS180 as woofer and I thought that a bit shallow...

C

[---k---]

I'm modeling up the boxes so I can make them work best for my situation, as I understand it, I want about 50l for each woofer, 15l for the mids and the tweeters don't care. I will be keeping the width of the front baffle as small as I can (11 1/4") in width

Phil

You don't need that much. My box is 100L total, then minus the 15L for the mids. So, each woofer should have ~42L. Its all sealed, so it isn't a big deal.

Also, note mine are 11" wide.

[---k---]

I know the crossover would have to be changed, but how significant is that? Can someone (subtle hint) just change things based on modeling or is it a "start from scratch" thing?

Phil

It will require a very different crossover. I think I'm hearing CJD say that because of sensitivities, it would require some padding (which he likes to avoid) and likely switching the tweeter. To do right, it would probably take remeasuring everything.

I've been around long enough to see that when a crossover change is easy, CJD usually has it done within in a day or two with little prodding.

[Bigdaddy]

OK - it looks as if the in wall version isn't going to happen because it would require a custom x-over and this would be very room specific.

Can I make the speaker significantly wider without ruining the sound? I need to keep the speaker as shallow as possible.

If the width of the speaker needs to be narrow for sound reasons (baffle diffraction?) can I make just the tweeter and mid area narrow and make the woofer area wider?

Can I space the woofers differently than what is shown?

Thanks

Phil

[---k---]

OK - it looks as if the in wall version isn't going to happen because it would require a custom x-over and this would be very room specific.

Can I make the speaker significantly wider without ruining the sound? I need to keep the speaker as shallow as possible.

no

If the width of the speaker needs to be narrow for sound reasons (baffle diffraction?) can I make just the tweeter and mid area narrow and make the woofer area wider?

no

Can I space the woofers differently than what is shown?

Thanks

Phil

How would that help? Probably best to keep them the same too, but there is a little bit more wiggle room here.