Highend bookshelf with matchin centre design?

[SoundEngine355]

Hi All,

I want to build a pair of bookshelf speakers with a matching center.

A pair of Zaph ZD5 is on top of my list with a third on its side as a center, would this work? Any other recommendations?

[Jed]

You could do the ZD5 pair as mains, but don't put the center on it's side. Keep it vertical as designed for the best performance.

[SoundEngine355]

What about a centre? I would like to use matching drivers.

[Hdale85]

He said just make a 3rd of the ZD5 but don't lay it on its side just stick it on top of your TV the way it should be or under or wherever. Will make a good center this way. Other then this I don't think you'll find a matching center design.

[Landroval]

The best matching center design for a bookshelf speaker is a third identical speaker oriented the same way as the mains...

[LunarD]

You want to put a ZD5 on its side because you have a height restriction. What is the height restriction? If you want ZD5's as your mains, you have two choices. Use a ZD5 as your center(vertically oriented), or use a phantom center. There are no other designs out there that will match a ZD5. That being said, lets see if we can't modify the ZD5 to fit your needs as a center.

The ZD5 has three requirements: 1) The front baffle must have a width of 7 inches with at least a 1/2" round over. 2) The center of the tweeter must be 3.5 inches below the top of the cabinet. 3) The sealed design, which you should use for the center, is in a .5 cubic foot enclosure.

For the sealed design, which you should use for the center because of the size, the example enclosure is 7"W x 16"H x 13.5"D which is 957 cubic inches. Since we can't modify the width of the enclosure, let’s modify the height and depth. The simplest suggestion would be to flip flop the height and depth which gives us a height of 13.5" and a depth of 16". If 13.5" is still too tall, you can remove up to another 1.5" from the bottom. Remember, you can't move the tweeter closer to the top than it already is.

Here are some sample height and depths:
13.5"H x 16"D
13.0"H x 16 5/8"D
12.5"H x 17 3/8"D
12.0"H x 18"D

Try to go for the tallest enclosure that will work for you.

Hopefully you aren't saying 12" is still too tall. If you are, it is possible to make it shorter. It won't be a true ZD5 anymore, but it will still be better than putting it on its side. It is possible to take up to 3/4" from top, so that the center of the tweeter will be 2.75" from the top of the cabinet. This will give you a height of 11.25" with a depth of 19 3/8". If that is still too tall, you are SOL. Just use a phantom center.

Shrinking the height increases the depth quite a bit. What if you have a depth restriction as well? As with the above modification, the speaker will no longer be a true ZD5, but hopefully it will be close enough. Keep the front baffle 7", but make the back width larger. This will give your enclosure a trapezoid shape, and will decrease the depth of the cabinet.

Here is the calculation for the volume of a trapezoid:
V = (FW + BW)/2 * H * D

V = Volume
FW = Front Width
BW = Back Width
H = Height
D = Depth

Be sure to subtract for the thickness of the walls. FW should always be 5.5(7 - 1.5), and your volume 957 inches.

So...
957 = (5.5 + BW)/2 * H * D

If you know your maximum height and depth and need to know your back width:

BW = (957/(H*D)*2) - 5.5

Which give us:

BW = 1914/(H*D) - 5.5

If my formula is wrong, please let me know.

With either of the last two modifications, it really should have a different crossover. However, since I doubt anyone will design one for you, the modifications are definitely better than lying one on its side. And who knows, you might not even be able to tell the difference.

If you do go this route, swap the center with one of the mains and try to compare the two. Also, post some pictures and give your impressions.

I've never listened to any of Zaph's designs, but the ZD5 looks like one of his most thought involved loudspeaker. I really like the fact that he pulled off an LR2 crossover. Off topic, I'm actually suprised he didn't use an LR2 in his newer ZRT.

John

"As a math atheist, I should be excused from this."

[cjd]

There are going to be more issues here than just fit - you pretty much shouldn't change tweeter-to-top dimension or width - look to the two options Zaph already has posted for the limits of change here.

Mounting this above or below a glass box (TV) will also change things quite a bit and may not result in sound to suit the quality of components being used here. Of course, we don't have any information about how this might be used relative to other equipment, so this is a guess without any way of knowing for sure.

C

[David_D]

I would be remiss if I didn't suggest the Statement Monitor / Center design. Jim, Curt & Wayne are awesome!