new project, need input please

[drfrink24]

I'm considering building a two-way system with the following parts:

Tweeter: Dayton 1 1/8" silk dome

http://www.partsexpress.com/pe/pshow...=275-070&DID=7

Woofer: Dayton 6" Reference Drivers

http://www.partsexpress.com/pe/pshow...=295-362&DID=7

What I want to know is, do these look like a good combo? Also, does anyone have a crossover design that they think would work good with these?

I'm thinking ported design, because I'd like to have them floorstanding, however, sealed is also an option, with stands.

[cytokine]

I think those 6" drivers just came out so I'm not sure anyone has a proven design with them yet.

For what it's worth, I just built these which use the silk dome tweeter you are contemplating.

I've only read one bad opinion of that tweeter and I think it's very nice for what it costs.

I suspect that the 6" driver will sound very nice. Let us know if you find something, or better yet, if you design it yourself and it works.

[drfrink24]

Thats the problem... I've got very little knowledge on creating crossovers.

From what I'm reading, sometimes I feel like its as easy as just selecting two drivers with similar efficiency, then choose a crossover point thats not to close the the limits of the drivers, and you're set.

Other times, the articles I read talk about in phase/out phase axis response, coupled with baffle considerations, peak impeadance with voice coil temps, discombobulator shafts being in line.... It just goes WAYYY over my head....

[wintermute]

Hi Drfink,

The thing I would be worried about considering your lack of experience with crossover design (which I also lack).... are the very substantial peaks in FR of the woofer at around 6Khz, 9Khz and a bit over 10Khz.

I think these could cause you some greif..... If the midbass just started rolling off nicely at 3Khz (ideally a bit higher than this...) and didn't have the peaks, I'd say it would be a much better proposition.

You could consider crossing it around 2.5Khz which I think both the tweeter and the midbass would be ok with, but those peaks look nasty!

Tony.

[drfrink24]

Yes, that was what I was thinking myself. Crossover at 2500 hz, but, is it really as simple as following some charts for the given 8 ohms?

[Hybrid fourdoor]

in my opinion, with the new RS line, if you go with 2.5Khz, you may want to consider 3rd order....but if your gonna go there, you may as well go 4th order. With a 4th order at 2K, the tweeter and woofer should be really happy.

[joe carrow]

I'm no expert at crossover design, but I've read about it on the internet.

A few things to consider that might improve your success-

First of all, the driver might have a "nominal" impedance of 8 ohms- but at the crossover frequency it could be somewhat higher or lower due to the resonant properties of the system. The impedance graph provided at PE should be a big help.

I would recommend using a 4th order crossover. The reason why is because (so I've read) it is in phase at crossover, and because it will help with those peaks up high. I've always heard that a good way to avoid nastiness outside of your passband is to use a steep crossover.

If you really want to take that impedance thing to the next level, you've got to remember that your box is part of the system, and will affect impedance (frequency dependent). You may want to measure that yourself. Remember- going bonkers over the exact impedance is NOT necessary- just a possible way to get the last little bit of perfection.

I've been looking at these drivers as the middle of a 3-way, but I do believe that you can get some good sound out of them in a 2-way. They're not going to have a lot of bass (that's why I'm looking for a 3-way).

That's just my two cents- I'll be watching the thread, because they seem like a very promising line of drivers.

[drfrink24]

I've got a pretty good idea of the cabinet I'm intending to make, and I think it will have a QTc of .707, however, I may drop to .5XX if I want to make them floor standing.

The cabinet itself, I'm going for something different. Maybe you guys will have insight into this as well.

The cabinet will be narrow, possibly as narrow as 6.5 inches. The face will be two 3/4" MDF thick. But, here is the unique part:

I plan on using 6" PVC pipe, bisected, as the entire back of the cabinet. The bottom, front, and top will have 1/4" grooves cut 1/8" deep, where the PVC piping will slide into (caulked), with a final top cap installed.


I've haven't seen/read anything to say that this would be a bad design. My impression of using tubes as cabinets are OK, as long as you still have an adequate baffle (which this will have).

Does anyone forsee any unwanted anonomlies or problems with this design? I will be padding it as well, I assume there won't be as many corners for standing waves either....

[drfrink24]

Oh, another thing...

4th order crossover.. What type will that be? Does anyone know of a good reference for a scematic, also, where I will be able to find the correct values for the components?

Besides the design goals of the speakers, I'm looking to build my first crossover, so, that is 50% of my goal to this project.

[joe carrow]

try searching google for "passive crossover design" "crossover calculator" and things like that. There are a lot of resources.

Also- your idea that a curved back baffle could help against standing waves.. it seems more likely that you'll have problems with waves along the long dimension. Look into the "golden ratio" box. That is- the longest dimension is 1.618 x the middle, and the middle dimension is 1.618 x the shortest.

Also, what sort of bass performance are you looking for? I don't really think this will hit 40 hz sealed. Will you be using a sub?