BMS+DSS+RS225=? HT Mains

[NEO Dan]

I've got no room for dipole, and no budget for the C90.

The BMS 4540ND+DSS 1-90ENG combo sounds like just the ticket for an over the top box speaker.

Is 2 way WWTWW with the 4 ohm RS225 feasible?
After a look at the impedance control circuit, I know the X-overs won't be cheap.
I'm looking at a baffle width of 11" and I want go ~80" tall. I've not settled on a bass alignment but I'm looking at what I can do in ~200 liters

Drawn 11" x 80" x 20"

[ThomasW]

It probably needs to be a WMTMW or a 2.5 way to avoid comb-filter effects

[NEO Dan]

Would I be able to avoid it (comb filter effect) by crossing over lower than the wavelength of the C-T-C spacing? Originally I had 11" spacing. Now I'm considering going ~10" and lengthening the line source to achieve full line array loading for the woofers. I'd like to crossover between 1-1.2K.

Any suggestions welcome

90" 11"

[augerpro]

Cool idea. If you cross low enough to the RS225 just above and below the CD you should be ok. Just be sure the other RS225s are either crossed as a 2.5 way or 3 way woofers.

Earl Geddes has indicated that the B&C DE250 can be crossed as low as 800Hz so maybe that would ease your spacing problem, although I would have to the math to see exactly what you need. And PE has them on sale right now.

[coctostan]

Why not check out some pro drivers for the mids? They would keep up better on efficiency.

[JoshK]

The DDS ENG 1-90 has been independently verified a few times by different DIY'ers that it looses directivity control around 1.2Khz so the crossover has to be around 1.2-1.4Khz. That puts the constraint on the c-t-c spacing.

[NEO Dan]

Why not check out some pro drivers for the mids? They would keep up better on efficiency.

That's exactly what I was thinking at this point, A good 8" or 10" would be just the ticket. A little trimming of the horn flange to blend them together.

Any suggestions? Mabey CIARE or B&C?

[NEO Dan]

I was looking around on US Speaker they have a few 16 ohm Drivers that might be goos for the 4 driver setup 8NW51-16 and 8PS21-16. Anyone test any of them?

18 sound has a preview up of a 10NMB420 that's 16 ohm, looks interesting.

None of these really are capable of going as low as I am interested in going. OTOH if you were planning on crossing over at 80hz you could be good to go.

[augerpro]

If you are looking to stay with a slim line and use 8" woofers, you are probably not going to get the bass response you are looking for without buying a lot of drivers. I think matching the CD to the RS225 is still a great idea, and a reasonable price. A 2.5 way would be perfect for this design. Good pro drivers will up the cost considerably.

If you do go that route though I would suggest the B&C 8NDL51 or 10NW64 for a high performance mid. The 18 Sound xxNMB420 drivers are good too, but from the testing I've done so far I think the B&C are overall a little better, especially as mids. But you're talking a totally different speaker now, and totally different looking.

Joshk if the DDS loses control around 1.2k doesn't that imply a crossover point considerably higher? Or is fairly gradual loss of control? Not too happy to hear this, I had planned on using this for a pro audio dipole soon :M Although Geddes is importing some of his WG's to the US. So maybe I'll wait and see what the pricing is on the 10"

[NEO Dan]

Brandon,
I think you are right on about the RS225, and I may go with the 4 driver 2.5 way setup to get my feet wet. I had really wanted a full line array and high sensitivity. But my wallet says :rofl: NO.

If you think the Sale @ PE on the B&C DE250 is a good deal take a look at the BMS 4540ND + DSS ENG 1-90 Pro combo in the Tiny Kit section over at assistance audio. :T

[A9X]

I18 sound has a preview up of a 10NMB420 that's 16 ohm, looks interesting.

I hadn't seen that one. Interesting. Cheers.

[JoshK]

Joshk if the DDS loses control around 1.2k doesn't that imply a crossover point considerably higher? Or is fairly gradual loss of control? Not too happy to hear this, I had planned on using this for a pro audio dipole soon :M Although Geddes is importing some of his WG's to the US. So maybe I'll wait and see what the pricing is on the 10"

Well maybe I am intermixing the two. I understand the point, but I think people have been suggesting 1.2-1.4k xo but I think this is also where you start to loose directivity control. I'll punt to those who've more experience with this WG. I was just commenting on what I've read but maybe I've mixed up what I've read. I'm getting old it seems.

[Paul W]

My measurement PC is in storage now, but I did find this one screen shot for a BMS 4552ND on a DDS. Don't remember if this is 0-40 degrees or 0-60 degrees (probably 60) but you can see directivity falling apart below 1.4k or so...which is about what I used for an 8th order XO.

[NEO Dan]

Ok so the RS225 is gonna need to get intimate with the DSS, It's not like it can't be done.

[Dennis H]

Brandon, the DDS does lose directivity at 1-2K or so but an 8" woofer is pretty directive in that range so the combo isn't so bad with a cross somewhere in there. PE doesn't show a 60 degree curve for the RS225 but here's a CA22 at 0, 30 and 60.

[augerpro]

Paul thanks for the plots-very helpful.

Dennis I was hoping to match directivity through the crossover not "balance" a less directive driver with a more directive one , ya know? I'll have to measure both teh DDS and B&C 8NDL51 off to see if there is a happy compromise in there. Those graphs of the RS225 suggest maybe 1.5-1.8k Hz or so...I was hoping to go lower but...