Crossover folk, lend me your assistance

[joeybutts]

Going to build the enclosures for my master bath speakers this week while things are gluing up for my subwoofer builds.

I'm using the CSS WR125s as the woofer. I know supposedly I can just run it full range, but I also know it will be a lot better if I make it a TM.

http://www.google.com/url?sa=t&rct=j...jqZRJg&cad=rja

These will be completely in wall.

I was hoping to choose a budget to midrange tweeter, and was looking at the ND16. I've seen other designs where people allow the WR125S to run open and they just crossover the tweeter. Can I just borrow any crossover for the ND16 and pair it? For instance -

Maybe something like this?

ND16FA hi pass 2nd order:

R1 - 2 Ohms
C1 - 1.5 uF
L1 - 250 uH

These will be mated with just a T-amp, and my master bath is only about 640 cu ft.

If you guys think another tweeter would be better please let me know! There is a design out there using a Fostex tweeter, but at $50/ea, WAY more than I want to spend for the master bath. I'm crazy, not stupid.

[BOBinGA]

Joey,
Are you sure you want to use the paper coned WR125S? In the wet atmosphere of a bathroom, I would use a poly cone woofer. Your idea to use the ND16 would be fine if you were building this for a dry location.

-Bob

[5th element]

I second the recommendation for the poly cone, poly cone and a moulded poly basket if possible.

With regards to the tweeter xover there are three different ways, I see it, in which this can be done.

The first, is that you use the full range driver full range without any crossover at all. Then you cross in a small helper tweeter as high as is necessary to give you the top end sparkle that you want.

The second is that you make a proper 2 way out of it, but still crossover reasonably high, like 3-5k or so you can still use the same tweeter for this.

The third is that you decide to crossover to a reasonably capable tweeter, quite low (2kHz) and with steep slopes.

In terms of what's best. The first is the easiest and simplest to implement so has big bonuses just because of that, but it is also the most performance limited as it will suffer from off axis issues, both vertically and horizontally.

The second basically trades simplicity for a more complex design but in doing so puts the crossover in a place where you crossover the full range driver before any off axis issues would occur, but you're still free to use a very cheap and cost effective tweeter, you can also use shallower slopes to keep the xover costs down.

The third design, I see as the best of the three, but is harder to get right then the first, is more complicated and its execution is probably the most important. The idea here is to pick a more robust tweeter, that can crossover around 2k, this doesn't have to be overly expensive, the DQ25 will easily handle something like this, but it is obviously far more expensive then the cheap Dayton. What you do here, is keep the full range and tweeter as close together as you can and then crossover low and steep, 4th order etc. This means that you will have virtually no issues in the horizontal off axis, but as the C2C spacing is low vs the crossover frequency, if designed right, you will have a very large primary lobe and only small nulls either side of the lobe. This kind of design is very well suited to locations where you're likely to be moving around a bit and will will tolerate different listening heights far more gracefully then the other two. It is the hardest to design as it uses the tweeter right on the edge of its limitations and will require more xover components.

As to which I would recommend, well that depends on your skill level The in wall aspect does at least mean you don't have any bafflestep, or any gross diffraction issues to deal with.

[joeybutts]

Yes, it is in the bathroom but my bathroom does an excellent job of not holding moisture. I'm not overly concerned. My backyard paper cone speakers have held up fine to the VA rain storms, I think these will be ok in the bathroom. Appreciate the thought!!

Thanks 5th! I did indirectly get Johnny on PETT to draw me up a prelim crossover that I am going to try and see how it comes out. I believe he stated a x-over around 3k utilizing Bagby's program.

[5th element]

Yeah I figured Bagby's stuff would work well here as BS and the standard diffraction ripple before it shouldn't be present, making the design work slightly easier. 3k is good for those little dayton tweeters and should work well. Pushing the xover down to 2k with better tweeters would be the icing on the cake, but really that's me just nitpicking for the last couple of% that you might be able to pull out of the design and then that's only if you move around a lot too.