Topp's ZDT3.5 Build

[topp]

I am going to start making my ZDT3.5's today and start with my center channel and I have decided to start with the vented center. But in order to fit in my TV stand and get WAF I narrowed up the width of the speaker and moved the ports to the back. I also had to reduce the baffle height by 0.5", not ideal, but I had to. I modified the depth in order to maintain the same internal volume. However I do have a question, does it matter where the ports are located? Right now I plan on them almost lining up right behind the RS 180's. I wasn't sure if it mattered, I figured it did not, but I wanted to check. Also, for the people who have build the ZDT3.5 towers and/or centers, what frequency did you choose to tune your enclosure for (what length did you make your ports)?

[ThomasW]

Are you using a sub? If so there's nothing to be gained by porting a center channel speaker.

[JonW]

However I do have a question, does it matter where the ports are located? Right now I plan on them almost lining up right behind the RS 180's.

Thomas is right. But if you do use the port... I'm no expert, but I think you don't want to have it behind the woofers like that. If you need to put it on the rear, line up the port behind the tweeter. Or behind the mid if the mid is sealed. And make sure the port is the same distance from both RS180's. So in the middle.

Wow. This is really turning out to be a very popular speaker. Zaph has made another appealing design. :T

[topp]

I was debating the sealed versus ported center. I am going to use a sub too. My thought was if the mains were ported I might as well port the center too. However, since it will be crossed over anyways I am not sure how much I will gain.

[stangbat]

I tuned mine to the lowest option, 41 Hz. So this means that when you butt the ports together the overall length is 4". I listen to 2 channel audio and I don't have a sub, so I wanted the lowest tuning. I'm actually very happy with the bass performance without a sub, although I realize that for HT a sub is needed.

I agree that if you are using a sub, there really isn't any reason to port the center. No problem if you do, but no real advantages. You could sigh and tell your wife that to make her happy you will compromise and build the sealed version. That might earn you some pity points? :T

[ThomasW]

If you're going to run a sub and use the standard 80Hz XO point, you gain nothing by building a ported box.

Mains or a center with midwoofer drivers this size should be run as "small" this means all the bass is steered to the sub....

[Dennis H]

And the RS180 is one of those drivers that's 'custom made' for an 80Hz 'THX' crossover in a sealed box. To work with recent receivers, you want the box tuned to Q=.7 at 80Hz and that works out about perfect for a pair of RS180 in 17 liters or so with light stuffing. The ported box will give you better bass extension without a sub but the blend to a sub with an 80Hz receiver crossover won't be as good.

[topp]

stangbat, I like your idea about trying to earn some pity points.

Since I am going to use a sub and cross over the center at 80 HZ I will make the sealed center.

I ordered all my crossover and drivers last week, and of course the RS 180's and a couple of the restitors were back ordered. Does anyone know what diameter they made the through hole for the RS 180's along with the diameter and depth to flush mount them?

[Jed]

I don't think the RS180s are backordered anymore. I just got a bunch of them.

[topp]

Okay, I have had some progress on building my center's and mains. Since the wife decided she wanted them black, and I am cheap at heart, I decide to paint the baffles textured black and use some of the Partsexpress's Black Ash Vinyl Laminate. I had enough left over from when I did my AV-2's to do the center. I was really surprised how easy the textured paint coated.

I didn't order any of the Sonic Barrier yet, but I was wondering if putting any of this, http://www.edesignaudio.com/product_...products_id=51, on the internal walls was would do anything? I have quite a bit left over when I used it on my doors of my car. Also, does anyone know if any cheaper alternatives to the Sonic Barrier?

Thanks,
Topp

[ThomasW]

but I was wondering if putting any of this, http://www.edesignaudio.com/product...&products_id=51, on the internal walls was would do anything?

It's designed to mass load metal, that's not the kind of damping a wooden box needs.

Use plain old fiberglass insulation nothing is cheaper and very few things work better

[topp]

When you say plain old fiberglass insulation, do you mean the pink stuff? Would carpet pad be any different? Just thinking that would be cleaner, and less itchy.

Thanks,
Bryan