clasic hifi dome tweeter with pa horn

[Biscu]

Hi all,

I want to use the 18 sound XT120 Eighteen Sound - Professional loudspeakers

with a hifi tweeter, in the range 89-93 dB , for 3 way diy project ...

From what I have been able to find , it seems it can be done but with a few restrictions:
- not classical dome, but ring radiator would be recommended
- 3/4" dome diameter due to fit with 1" gauge of the XT120 horn

So, please tell me if I am (very) wrong and what cheap/affordable tweeters would you recommend for this case, 8 ohm impedance if possible but not a must ...

Also if you are kind, a midrange (also hifi drivers) recommendation and crossover point for horn-tweeter and midrange. (also affordable price drivers)

In my plan I think about a 5" midrange in open baffle and a 8" (or 10") bass driver in closed box.

I could by most of the drivers from Europe online shops ... but not from US.

Many thanks

 

[Lojzek]

The right horn for a hifi dome tweeter is a waveguide, like Monacor WG 300. Made to fit a Monacor DT 300 although you could probably use any other unit with a mod or two. As a midrange unit there is so many options that it boils down to a personal preference. I prefer easy to work with polypropylene cones, like Peerless PPB. A xo point between mid and tw should be around 2-2.5 kHz, midrange being 5.25" class.

 

[Patrick Bateman]

SB Acoustics SB19 works great. Check out my projects, I've posted numerous measurements with that dome tweeter and various horns and waveguides.

 

[Biscu]

Thank you!

I know about Monacor and Visaton waveguides, but I worked before with 18 Sound horns (XT1086 with BC DE250) and liked really much and now I would like to try this XT120 but not with PA drivers ... to much spl ... and now I will use mid and bass with rubber surround from hifi speakers.

Nice ideea with SB Acoustics SB19 ! And is affordable too ...
Also heard about : Peerless by Tymphany XT19TD00-04 3/4" Dual Radiator Tweeter - SoundImports
and SB Acoustics SB21RDC-C000-4 3/4" Ring Tweeter - SoundImports

Maybe is worth to mention my plan to use active crossover
234s | dbx Professional Audio
and amplification
A-700 – Emotiva Audio Corporation

So, a good midrange 5" - 5.5" driver for open baffle use ? Any ideas?

 

[Patrick Bateman]

I tried the XT19 and I didn't like it.

A ring radiator has a fraction of the displacement of a dome. So a 3/4" ring radiator barely has any displacement at all. (Because a ring has less area than a circle.)

I guess it depends on what your SPL requirements are, but I personally prefer the 3/4" domes if you're going to use a dome on a waveguide.

And be sure they're silk, titanium and aluminum are a p.i.t.a. on waveguides.

 

[Biscu]

It makes sense ... I will remain at SB19, it is what I was looking for. Thank you Patrick!

Now, I will have to find a nice midrange driver to blend with this combo horn-tweeter (SB19 with XT120) and that midrange will be in open baffle ...

Any good midrange (from closed box) will still be good in open baffle? or for open baffle the midrange driver should have some special qualities/parameters?

It seems this midrange will work between 300 or 400 Hz and 2000 - 2500 Hz.

Maybe the OB group can give me some suggestions ...

 

[Patrick Bateman]

SB19 definitely isn't the only choice, just one of many.

I've tried the neodymium JBL GTO 19T on various waveguides. It's nice, but it's not as extended as the SB Acoustics.

Here's some data, showing the two tweeters on the exact same waveguide at the same level:

JBL

SB Acoustics

Basically the very small back chamber of the JBL is raising it's efficiency, but also raising it's F3. I'm not 100% sure why the JBL runs out of steam at 16khz, I think it's probably the tweeter grille.

Note that the SB Acoustics measurement has been equalized.