Manage a trois?:P

[raypalmer]

Always wanted a 3 way....



What say you, kind gentlemen of sound? I want to make a 3 way of original design, and I was hoping the forum could give me a jumping off point. With advice on crossover etc. I hope to fiddle some lovely speakers out of this endeavour.

The parts I want to use are thus:


Tweeter, Dayton ND20FB-4
Midrange, Tang Band W3-319SF
Woofer Dayton, DC200-8


Reasons for choices: I have used the ND20 before and like it, used the 319 before and loved it, also they are cheap. I know the TB is a fullranger but it should work wonderfully crossed in to a 3 way I think. The woofer is just a guess, it's cheap which is crucial and I'd rather use an 8" than a 6.5" if possible.

I would plan on building a two-tiered tower with the lower section a BR for the woofer and the upper a BR for the M and T. Before I go nuts crunching enclosure volume numbers what type of XO would be good? Any suggestions?

I like the high end, and enjoy a little sparkle of brightness. Any XO I build will doubtless be tweaked and re-tweaked so if someone could even just tell me what type (1st, 2nd, 3rd order, butter?), seemingly ideal crossing points would also be greatly welcomed.



P.S. I'd be driving them with LM3886 Monoblocks ala chipamp.com.

[PeteMcK]

if you need BSC, to avoid padding the mid, I'd go for a more sensitive woofer, or use two...
xover points, ~200Hz, 4-5Khz?

[raypalmer]

Originally Posted by PeteMcK

if you need BSC, to avoid padding the mid, I'd go for a more sensitive woofer, or use two...
xover points, ~200Hz, 4-5Khz?

I was a bit worried that that 88dB number would be an issue... what about this silver flute with 91.5dB sens?
But I prefer an 8" woofer if I can. You say that if I were to use two of the Daytons that could help? I'm not sure I understand why.

[PeteMcK]

you get +3dB because of double Sd, and another +3dB from the amp because you're driving half the impedance, assuming parallel connection...

Have you though about room placement, and how wide you want to make your cabinets?
if they're wide &/or against the wall , you may not need any BSC...unless you like heaps of bass like me...

[raypalmer]

Ahhhh so in parallel they're 4R and I get the plus 3. I was considering front firing ports to allow me to tuck against the wall. And with the 8" woofer I was thinking 9 or 10 inch width.

Sounds like doubling up on the Daytons is the way to go. But I'll need an L-Pad to attenuate them back down owing to the low sensitivity of the Tang band won't I?

[PeteMcK]

No, don't pad woofers, that'll just waste power...
If they're against the wall, you won't need BSC, so single driver is OK & will match the mid well.
Are you going for an all passive xover? - Bi-amping is a really good way to go if you've got a spare amp, as well as eliminating the woofer matching problem. Simple to do with a PLLXO.

Woah! just did a quick sim in Unibox, those woofers are gonna need a very large box....at least close to 100L; maybe look for something similar with a smaller Vas?

[PeteMcK]

sims in unibox for pairs of the dayton 6":
2x dayton DC160S-8 in parallel, 27L tuned to 42Hz > 89dB
2x dayton DC160s-4 in series, 32L tuned to 41Hz > 90dB

[raypalmer]

Hmmm. As a money saver. If I'm going to use 4 woofers I may as well use a woofer I already have two of. This peerless specifically. I'll unibox these and see what comes out...

If bi-amping I would match the woofer section to the mid-highs by attenuating one of the amps correct?

[raypalmer]

Okay unibox doesn't work in openoffice.... this is sad for me.

[dantheman]

would plan on building a two-tiered tower with the lower section a BR for the woofer and the upper a BR for the M and T. Before I go nuts crunching enclosure volume numbers what type of XO would be good? Any suggestions?

I don't think I'd do BR for the MR driver if you plan on using a speaker level passive crossover. Taming the impedance peak will be expensive. I assume you're trying to do this on the cheap--aren't we all. A damped line or aperiodic box would be better I'd think with the aperiodic possibly easier to implement.

I'm a big fan of line level filters, but it's hard to get a steep passive w/o a ton of loss. Active filters will add some noise, but the benefits in my system well outweigh the drawbacks. Fourth order seems to be plenty steep and you could probably get away with less. Typology seems too much of a personal and system choice for me to go any further.

What do you think?

Dan