Pro JBL question

[Andyoz]

Hi,

I am working on a music venue refurbishment and have a chance to buy a pair of JBL I732, 15" 2-way boxes. They are from JBL's 1990's "Sound Power I-series". http://www.jblproservice.com/pdf/Systems%20Reference%20Charts/Sound%20Power%20I-Series.pdf

For my work, we somethimes need to generate high levels of pink noise or music in medium sized rooms for sound insulation testing. Our existing kit (http://www.bksv.com/pdf/Bp1689.pdf) only has limited capacity so I have been on the lookout for some decent 2-way boxes.

I understand they are fitted with 2227H woofers and 2447H highs. Any opinions about their quality/worth. It's not sound quality I am after, just ruggedness!!

[Guido]

I haven't heard them but the components are bulletproof :)

[Andyoz]

Yes, that's my reading of the spec's as well. Trust me, these things get some serious abuse - pink noise is a killer.

There's isn't much info available on the I-series, but I think they are designed to be bi-amped (no passive x-over). Will find out when I get a good look at them.

[Mike Caldwell]

Regardless of the speakers you find and use I would recommend the use of a high pass and low filter in the system. Something like 50hz and 16,000hz. That will help preserve the drivers...unless your testing needs extended band width. Also when bi-amping you could move the crossover up to around 1700hz and that will enable the driver to handle more power.
How much shear output are you looking for and in what size of test area. You'll need some good amps of adequate power so your not driving them into clip, doing that for any length of time no drivers will last very long!

Use ear protection!!!!

Mike Caldwell

[Andyoz]

Most of the testing is for the R'w parameter and that is bandwidth limited to 100Hz and 3.15kHz.

The seller is asking too much for the JBLs's so I am thinking I may buy some (near) new active 2-ways. Something decent, I like EAW but they are not big on actives. I also plan to use them occassionally for parties etc.

I basically need to generate about 100dB flat through the 1/3 octaves in rooms up to 1000 cubic meters. Anything bigger than that (i.e. cinema commissioning) and we hire in a big PA rig like two EAW "stacks" - it's a real blast to hear them going hard on pink noise in a big room (even when wearing hearing protection).

[Hoerninger]

.. just ruggedness!!
Both drivers are high efficiency drivers, you can hardly get more per speaker.
Both have a 100 mm voice coil good for heat dissipation.
The bass unit has max 50 mm excursion peak peak before damage (5 mm Xmax)
The bass driver nearly makes the bandwidth alone (with changing directivity) with 600 W continous pink noise.
http://www.jblpro.com/pages/pub/components/2227.pdf

I would try them. ( Use ear protection!!!! Mike Caldwell)
__________
Peter

[Andyoz]

The seller wants too much for them! And I know from contacts that they got a very good deal on the whole rig when they bought it new 15 keays ago so they are just being tight buggers.

I have a contact that bought up a load of superseded EAW gear in April (JF560z at 40% RRP) so will probably go with them and match them to a Crown XTI 4000. The amp has on board EQ, crossover, shelf filtering - I will probably get a XTI 4000 first and run them passive for a while and add an XTI 2000 later and use that to run the horn in a bi-amped system.

[Mike Caldwell]

Hello
The XTi amps work well and offer a lot of processing in the amp, I have used many in installs with not problems. To fully use the DSP processing you need to download the Crown/Harmon HQnet software and connect the amp vis USB to your computer. The front panel control is very limited.

Mike Caldwell

[sa660]

Andy,

A friend of mine has a few pieces for sale made by Electrovoice. He is based near Clonnell.
They are old and abused but I am sure that they will give you more than 100db from 100Hz to 3.5 KHz. the cabinet are 15" and 1" compression drivers.
He also have 18" Cerwinvega subwoofer used in Cinema if you want to extend below 100Hz at 100dB.

The JBL is a very good buy and the 2227H can be update in a top class subwoofer ME150HS. It is the same magnet assembly and frame as the 2227. You just need a recone. You can find the ME150HS in the 4344MKII and the S3600 (mini version of the Everest DD55000).
Do you mind me asking what pricefor the 2227 and 2447?
I have a JBL 6260amp if you are struggling for power amplification.

[Andyoz]

Thanks,

They want nearly €1,500 for the pair of 2-way JBL's. I can get very good new gear for that!

Re. the EV's, I will also be using the gear for some other (personal) stuff so I don't want it too banged-up. Still hot on the tale of the EAW's as they seem a very good buy and they are definitely a rugged design. Still checking out amp options. I may be able to get a good deal on a Crest Pro 7200 and outboard DSP (Ashly Protea) but really need to think if I need something THAT good!!!

I have decided I need one of the lightweight amps around 10kg. My Bryston at home is 22kg and that's about twice the weight of anything I want to lug around (when including for flight case and external DSP 1RU module).

There are mnay power amps on eBay but can be risky as you don't know what many of them have been through..