ZRT Update and Impressions and Google Sketchup Help

[djn04]

So I've had the ZRT's completed for a month or so and I am very impressed with them. I've listened to them next to a pair of Sonus Faber Cremona's and while not as full a sound they do compete nicely and are just as detailed. Well worth the money in my opinion.

So that got me to thinking. Sonically they are very impressive, but aesthetically/cosmetically.....not so much right now. My new plan is to build a cabinet to replicate the Magico V3's with translam baltic birch and a curved baffle made of MDF.

Image not available

I've been messing around with Sketchup trying to make some CAD files that I will get CNC routed. I've got the cabinets complete but I'm having trouble with the baffles. Does anyone know how to make the curved part extend all the way up the baffles unlike in this picture? Or a forum that could help me out?



Here's what they look like now. They're the white ones. :W

[Rolex]

Could you talk a little bit more about the comparison between the Cremona's and ZRT?

[tktran]

Since you've already built them, why not build different speakers if you are going to build new cabinets?

With all that work going into new cabinets, you may as well try the 2.5 MMT
ZRT...

[djn04]

Rolex-

I'm not sure how to describe it but the ZRT's and Cremona's share the same woofer but the Cremona's have 2, they have similar tweeters and the Cremona's are 3.5 way where the ZRT's are 2 way.

The result is that the ZRT's have a similar sound just not as full. At the same volume the Cremona's sound fuller like there is more sound reaching you without an increase in volume. I think the ZRT's have a similar amount of detail and a deeper bass (probably due to the tuning of the cabinet).

tktran-

The good thing about the new cabs is the baffles will be removable and the sealed 2.5 ZRT fits in the same enclosure as the ported 2 way. So I'm going to make a baffle for the ported 2 way and then in the future if I want to go 2.5 I can just make a new baffle and crossover.

Picture of the nearly completed baffle.

[lunchmoney]

Love the look of that baffle... but doesn't the ZRT's design require that the tweeter be flush to a flat baffle? Perhaps the curve in the baffle is slight enough that it doesn't matter... but Zaph is quite adamant about the tweeter being flush.

Also, how do you plan on making that baffle?

[sdl2112]

I was curious how you plan to do the Baltic Birch translam portion of the cabinet? I have something similar in mind but I am finding it difficult in how to do the stack up of the BB without over-constraining it. After seeing this thread I want to make sure the appropriate panels can float.

[djn04]

Lunchmoney-

I'm only doing this because my painted cabinets didn't come out nearly as good as yours :B You can see in the picture below that with the tweeter flush on the sides the baffle is raised on the top and bottom. At the highest point in the curve the baffle is 3/16 of an inch above the tweeter. I would plan to roundover the edges of the hole slightly as well. Do you think this will adversely affect the design?

[djn04]

sdl2112-

I read that thread as well. I think the difference with this cabinet is the lamination is vertical as opposed to horizontal. Also with this design I will have threaded tubing running from the front to the back and bolts on either side. This will keep tension on the lamination and I hope will not allow it to separate. That's how the magico v3's are made so it should work.

Lunchmoney-
I'm going to export the sketchup file to a CAD file and I have someone local who can do all the cnc routing for a reasonable price. The baltic birch on the other hand....not so cheap.

[djn04]

So this is what I'm thinking it will look like in the end

[djn04]

This is the latest and it ready to have the cnc routing done. I'm still nervous about the tweeter and the flush mount issue Lunchmoney brought up. Does anyone have an opinion about that?

[Chris7]

This is the latest and it ready to have the cnc routing done. I'm still nervous about the tweeter and the flush mount issue Lunchmoney brought up. Does anyone have an opinion about that?

That's a fantastic aesthetic design.

You will get some frequency response irregularities due to diffraction from the ridge around the tweeter. You'll also get some from the edges of the cabinet not being rounded. However the curved baffle may help to smooth out others. Overall the FR will probably be slightly rougher than a flush mounted tweeter on a flat baffle with rounded edges. However the aesthetics may be worth it.

[djn04]

Chris-

Thanks. I'm excited to put this plan in action. Another possible issue is the overall width of the cabinet. The original design is 9 inches wide. The new design is 10 inches wide with the baffle being 9 inches wide. The internal dimensions of the cabinet are identical to the original design it's just the external width and the baffle that are different.

Other than the diffraction issue Chris spoke of does anyone see any issues with increase in width.

Thanks.

[Chris7]

Chris-

Thanks. I'm excited to put this plan in action. Another possible issue is the overall width of the cabinet. The original design is 9 inches wide. The new design is 10 inches wide with the baffle being 9 inches wide. The internal dimensions of the cabinet are identical to the original design it's just the external width and the baffle that are different.

Other than the diffraction issue Chris spoke of does anyone see any issues with increase in width.

Thanks.

The increase of width affects the baffle step frequency. However it won't be a huge difference.