Tops to accommodate Xoc1's T18

[weltersys]

Art, how about 4xB&C 6NDL38 w/ 2xBMS 4550 per box?

Panjilaras,

The B&C 6NDL38 dig a little deeper and have more Xmax than the Eminence Alpha 6, but are a lot less sensitive.
They look promising,(given more power) but without hearing a driver in a specific box can't really say much other than 4xB&C 6NDL38 w/ 2xBMS 4550 per box should kick if properly designed and built.

Art

 

[tb46]

Hi Panjilaras,

I don't know if you need two BMS 4550 horn drivers to stay with Xoc1's TH18, maybe one would do it? When I typed "BMS 4550" into google this came up as a picture as the second item on the page: Future Projects That reminded me of all the other data William Cowan has on his website pertaining to "Unity Horn Speakers". That may be an interesting approch. I've never put the numbers to this, but Cowan's work always looks well thought out. Or, maybe 2ea. Eminence Beta-12A with one BMS 4550?

Regards,

 

[panjilaras]

hi Art & Oliver
I intend to do multiple boxes.
to be honest the 6.5x4 arrangement inspired from: Yorkville PSA-1

An externally hosted image should be here but it was not working when we last tested it.

more info on PSA-1
they use 18sound 6ND430
but I like the horn to be like VTC, as Art suggested.

 

[m R g S r]

So what's the consensus on passive tops to accommodate the TH-18's?

I've passed my pair of TH-18's on to a DJ who is looking for me to build him new tops soon.

He would like 4, to be powered off an XTI 2000...and the reason for 4 is so the system will scale. One TH-18 sub and two tops for small parties then Two subs and four tops for larger parties.

Easy portability obviously is key along with clean sound!

 

[m R g S r]

I will try to convince him to grab an XTI 1000 for HF power and go active, but I'm not sure he will go that route....

 

[weltersys]

Hi Panjilaras,
I don't know if you need two BMS 4550 horn drivers to stay with Xoc1's TH18, maybe one would do it?

The BMS 4550 is a nice sounding driver, but has considerably less (about 2 dB up high, 6 dB down low) clean output potential than the EVDH1AMT, I have tested them using identical horns.

http://www.diyaudio.com/forums/multi-way/212240-high-frequency-compression-driver-evaluation.html

I'm using 14 eight inch speakers and 5 EVDH1AMT (1.4" exit 3 inch diaphragms) on top of one 18" B&C18SW115-4 loaded Keystone tapped horn, that is 2 B&C18SW115-4, 28 Eminence Alpha 8, and 10 EVDH1AMT HF drivers total for left and right PA.

Xoc1's TH18 may not have quite the output of the Keystone, but I'd venture to say one BMS 4550 horn driver would not be up to the task unless one uses very little HF or does not mind excessive HF distortion and diaphragm replacement .

Art Welter

 

[tb46]

Hi Art,

Post #46: "...unless one uses very little HF or does not mind excessive HF distortion and diaphragm replacement..."

Thanks for the additional information (hard earned I'm sure). I was looking at DSL's unity horn and tapped horn spec sheets, and there is not much difference between, e.g.: the TH-118 and the SH-46. Now, I don't know what drivers DSL uses but five of the EV DH1AMT per 18" sub isn't that's being a bit extra conservative? The good thing is, they shouldn't be straining.

Regards,

 

[weltersys]

Hi Art,

Post #46: "...unless one uses very little HF or does not mind excessive HF distortion and diaphragm replacement..."

Thanks for the additional information (hard earned I'm sure). I was looking at DSL's unity horn and tapped horn spec sheets, and there is not much difference between, e.g.: the TH-118 and the SH-46. Now, I don't know what drivers DSL uses but five of the EV DH1AMT per 18" sub isn't that's being a bit extra conservative? The good thing is, they shouldn't be straining.

Regards,

Most of my shows are outdoors in hot dry high desert conditions. The combination of heat and low humidity makes for HF air attenuation of up 10 dB or more over sea level humid conditions, requiring a lot more HF level.
HF air attenuation is in addition to the normal inverse distance losses.

That said, the 28 eight inch mid drivers hit clipping about at about the same level as the two subs, and nearly a 3 to 1 ratio of mid drivers to HF drivers is not particularly conservative when trying to keep HF distortion low.
If I were to switch to the tiny BMS drivers, I'd need to double the HF driver count to 20 to "keep it clean".

Art