JBL Array 2235 Be project

translation -

The membrane will cost 500 €. Delivery within Europe is included.
On request, we build the membranes in your driver. This service is charged at € 49 per cone. An examination of the field strength, cleaning the air gap and an impedance sweep are included.
It is now possible with these membranes, a world-class large beryllium compression driver to get under 1,000 €. The only other large beryllium compression driver are the major TAD's, but which are priced above 2,000 euros per driver. You can hear us TAD drivers and JBL / Truextent drivers in direct comparison to a high-quality chain. Hear and judge for themselves what is the better alternative!
If we have piqued your interest, simply register, feel free to call maybe to dispel any doubt. Please allow at least 2-3 weeks for delivery one, because the membranes are in high demand.


They talk about TAD here, but I am uncertain whether they are saying the diaphragms work in TAD drivers, or whether they think them better value for money.

Any native german language speakers here?

 

I think they mean compare the TAD with the JBL/Truextent.
The guys name is Guido you can talk/pm him on the Lansing Heritage forum.

 

Yep.

 

Danke.

 

Recharging the ferrofluid

The use of ferrofluid in the pro 2435HPL does more than wick away heat it also helps further damp any resonances.

The 'pros' have a habit of over filling the vc gap, the drivers can also suffer a thickening of fluid as some esthers in the fluid boil off under very high power.
In sample tests the fluid contents varied widely due to sloppy PA teching.
The precise amount as spec'd is 100uL and is critical to the performance of these units.

That's the easy part, sourcing the correct ferrofluid in sensible volumes can be a problem as the manufacturer supplies in bulk quantities.
Some inside info established the correct spec as APG S38n.

Fortunately a few of us got together on Lansing HF and divi'd up a batch-the manufacturer kindly supplied charge packs of 100uL and 10cc bottles.[/url]

After dismantling the driver the first task was to remove the old fluid. The recharge packs contain a kind of blotting paper for the purpose;
[/url]

 

I had 4 drivers to work on; 2x 2435HPL's and 2x 2431 HPL's. I practiced on the 2431's first-I'd rather make my mistakes on £200 Aluminium dias/drivers than the Beryllium versions!
As it turned out the process is very straight forward if a little time consuming to clear the fluid.
The amounts varied across all 4 drivers so t'was a wise thing to recharge.
This shows the silly amount I pulled from one 2435;
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After removal the next thing is a thorough gap clean using masking tape(sticky side out) and one final wipe with isop soaked tape.
Then, snip the vial, hold over the gap taking great care not to let the mag suck it into the phase plug.
And the magnet just sucks it in.
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After that, reassemble the driver.
Was it worth it? To my ears most definately.

 

You should have been a surgeon...

 

If I was I wouldn't have to DIY I could afford to buy TOTL.

 

Finally

Been meaning to post this RTA response of the mid/hf horn since recharging Ferrofluid and going fully 3 way.

Mic @1m on axis with uhf.

Xover @750/10.4k, 2nd order bass/mid,4th mid /hf, minimal PEQ via XTA.

+/- 1dB ;-)



This project has been well worth the effort, the sound is wonderful, IMO they out perform the Array 1400 thanks to the Be mid/hf, the move from 2 to 3 way was well worth it too-that extra sparkle and air from the 045 Ti is very beguiling. They were great as a 2 way but perceived wisdom being not to push the 2435hpl out beyond 14-15k seems on the money to my ears.
Some criticise the K2 9800's horn/imaging in some rooms, the SAM1HF when rotated through 90' sorts the latter and it's newer profile/flare contour when used with the same Be driver offers a real improvement over the former, now if I could get my hands on some 1500al bass drivers.....

I'm more than happy.

Improvements would come from a 475Mg/Be or modern 4" JBL compression driver with a Truextent Be dia.
The other project has been stalled for way too long, it is an opportunity to build a more stylish smaller cab and
use a variation on the TAD horn or just sell the spare drivers and go for a 4" Be with the dosh.....

Cooky

 

I have started a little DIY project with some large 12 sided conical horns and am Awaiting 2435 drivers to mount on them.
Birch ply used for the horns naturally

Was going to use them with the GRF as bass unit and the Tannoy X/O to start with.

Should start a DIY thread about them really...

 

Wood mmmm nice, that'd be cool Steve, love to see what you come up with.
Cooky

 

Do I get a gold watch when we hit 10,000 views?

Having central heating installed so got speakers disconnected/moved.On reconnection I
thought I'd leave UHF off and open 2435 out all the way again-There is something very right about these running 2 way-could be the hf section power amp I suppose-but 2 way sounds more focussed, tighter, smooth as silk if slightly lacking some very high end sparkle.
Cooky

 

I think it means that we all come around to your place for a listen and cookies.

 

You are most welcome.

 

As good a time as any.

Plan for 2011 is to source some JBL 24** series(pref the latest 1.5" exit/coherent phase plug) comp drivers and recone with Brush Wellman Truextent Be dias.

Cooky

 

My plan for MMXI is to take your advice and build a pair of sealed boxes for the CPAs.

 

Dev, you could go the whole hog.....http://pteacoustics.com/

 

$44k? gulp!

We'll make that plan c.

 

Update

Decided after much research to investigate the Precision Devices PDN15BR40 bass/mid driver after hearing very good things about their midrange performance.[
Called for extensive cabinet mods. the new baffle is a 48mm thick ply/mdf/chipboard/mdf sandwich.The polygonal rebate cut out for the driver was easily done prior to assembling the baffle sandwich.
While I was at it I'd long wanted to reduce the height of the cabs so I removed 6 ins with a saw! Squaring everything off and re-bracing with a new base the internal volume is now 130L. The port was repositioned and reduced in length to 48mm.

Impressions;
After a run in these drivers are very quick with a lucid and detailed midrange. They sound more clean/modern than the JBL's but are lacking some of their character(colourations?) They're staying, the bass is phenomenal, the mids are really sweet and smooth, blending with the horns at 850 hz on 2nd order butterworth curves.The higher Fs and 38hz tuning is more room friendly sounding clean and flat down low. Power handling/xmax would allow some serious LF eq below 30 hz if needed but I'm missing nothing tbh.

Should change thread title now to PDN/Be Arrays

 

Very interesting.

(filed away for possible future use in a project of my own)