288-8K purchased:Now,which High frequency Driver?

**theophile** · March 30th, 2009, 04:02 AM

G'day fellow Altec Users.

I just bought a 288-8k driver.I plan to use this in an Azura horn(Aussie company)from approximately 350Hz to 6KHz.
The bass will be provided by 416Zs(below 350 Hz)which will remain in place in my Altec Valencia 846As.The Valencias are already used by me in a diy active system using the Accuphase F-25 active crossover.
I'd like some opinions about a high frequency driver to take over from the 288,above 6KHz.

I already have at hand two B&C DE250-8 drivers.
Would they be suitable to use with the 288s?Or would you guys recommend another brand of treble driver.I would be using an Azura Horn with the treble driver also.
I'd prefer to use a compression driver above 6KHz,and I realise that they quite often don't have much usable response above 13-15 KHz.
I am prepared to utilise another(non-compression)driver above(let's say) 14 KHz if I feel the need to obtain 20KHz.
I'm trying to keep the drivers from covering too wide a bandwidth,in order to minimise the horns' upper range beaming and get(somewhat) better dispersion.
I realise that compression drivers and horns aren't renowned for wide dispersion,and I am not seeking wide dispersion,just a reasonable dispersion hand-over between the drivers at the crossover points.

Am I thinking in a screwy way about this?Or do my ambitions seem reasonable.

PS the 288-8Ks I bought don't have diaphragms.Would any particular diaphragm be more suitable for this project.I'd buy GPA diaphragms(naturally).

**Vathek** · March 30th, 2009, 09:13 AM

Have you looked at BMS drivers? I have a similar setup and am quite happy with the BMS 4538 on a small tractrix taking over at 6-8K. Crossing over lower I didn't like them too much but as pure tweeters I think they're really very good and hard to beat. From the Altec family, IMO the 902's are the only driver suited for tweeter duties, but they do have the typical aluminum breakup at their top end. I find the BMS smoother and more extended. But that's only for tweeter use, in a two way I much prefer the Altecs.

The 18sound NSD1095N is supposed to have a great top-end with its treated diaphragm, but I have not heard it in person.

For the 288's I'd go with Alu. I've recently heard both Alu and Pascalites on 288K's on small Multicells (forgot what model) at a friend and for me the Pascalites don't have the 'snap' (for lack of a better word) that I like about Altec Drivers. But then my friend preferred the pascalites giving a smoother performance, so as usual it's all a matter of taste. Plus I don't know if there would be an audible difference when you take them out at 6K anyway. Personally I'd go with Pascalite only if a) your system sounds harsh to you or b) you really need the power capability.

**theophile** · March 30th, 2009, 09:50 AM

Thanks for the reply Vathek.
A friend is getting some BMS drivers(I don't know which ones),and has ordered me a pair.
I'll see how they go when I get them.

**magnarc** · March 30th, 2009, 09:57 AM

Ahah, thats who got them.

He has another pair on now, were the ones you got in good nick?

Nat

**theophile** · March 30th, 2009, 10:04 AM

I don't know he hasn't sent them yet.

**Vathek** · March 30th, 2009, 10:58 AM

They differ quite a lot. IMO the ones best fitted for tweeter use are the ferrite 4538 and its neo-successor 4540nd. They both have a high recommended crossover point and extended frequency response. I also once tested the old model of their standard 1.5K-crossover two-way driver (forgot the number) and didn't like it too much.. I chose the 4538 because the 4540 is a screw-on model and would need an adapter for my horn (and your azura too, probably).

**RonSSS** · March 30th, 2009, 04:03 PM

I'd use Altec 902-8A. Or, if you prefer alnico, 902-8g.
I believe the 902-8A was the best Altec small format driver.
Keep it all Altec!
Ron

**theophile** · March 30th, 2009, 04:24 PM

Originally Posted by RonSSS

I'd use Altec 902-8A. Or, if you prefer alnico, 902-8g.
I believe the 902-8A was the best Altec small format driver.
Keep it all Altec!
Ron

What about the GPA driver?

**theophile** · March 30th, 2009, 04:27 PM

My mistake:
The902-8A is the GPA driver.That may well be the one I will get.
The B&C driver has the option of 3 or 4 bolt hole pattern.I could get the GPA driver,compare the two,and use the one I like the best.

**gearfreak** · March 31st, 2009, 10:49 AM

I am using GPA 902-16A, on 511B, and now (just recently) experimenting with Dayton's:
H12RW 12" Round Waveguide 1" Threaded.

This also requires e.g. the Selenium ADM25-25* Horn Adapter for a 2 bolt driver.

* If used, I suggest filing or drilling the 2 bolt mounting holes very very slightly. Out of the box, mine 'grabbed' on the 902's mounting studs. So test fit it gentley, and don't push down all the way.

The 288's are mated with smaller altec MR horns. Model TBD.
Active Xover @ ~7k.

Initial impressions drive me towards the waveguide for nearfield use like mine.
(Perhaps that is obvious), but the jury is still out pending more experimentation.