High SPL Design Ideas

[theriam]

Greetings!

I'm a long time JBL fan and I'm in the process of designing a new system for a 50' x 30' room in our barn where we hold several large parties per year.

I currently have (2) 2446H drivers and am planning to order (2) 2242H 18" drivers shortly. I also have two JBL 5235 electronic crossovers and several amplifier choices (multiple Crown MA600, PS-400 and Ashly FTX-2001 units) available to build a tri-amplified system.

Space is not a problem and the ceiling is open to the roof structure - about 24' high. The horns and mid bass drivers will likely be suspended on a back wall with the subs on the floor.

Here are my questions:

Which 12" or 15" JBL driver (possibly 2 per cabinet) would be my best choice for optimal mid range and mid bass performance and efficency to complement the 2446H?

Which horn should I look for to mount the 2446H and at what crossover frequency and slope?

I'm thinking about building sub cabinets similar to the 4645C. Is this the optimal bass reflex cabinet design for the 2242H for the deepest, flatest response? Where would you cross it over to match the above?

I will likely buy used, late model parts to complete this system.

Sorry for the long post... I'm really looking forward to this project and would appreciate some advice and ideas from the forum.

Thanks in advance for the help!

Mike

[louped garouv]

how many folks generally gather for these events?

and is the entire space used as the main listening area,
or is the space used in fragments?

bar area, seating, dining, "dance floor", etc?

[pos]

Drew Daniels' system would fit your needs:
http://www.audioheritage.org/html/pe...ues/system.htm
http://www.audioheritage.org/vbullet...ystem&p=320498

[Lee in Montreal]

Theriam, are you open to suggestions? I am asking because using a pair of 2242 as sub-only means you will be missing 80Hz-to-500Hz.

Also, what will be the purpose of that system? If you mention SPL, I suppose it is for house parties...

Here's what I would do (I suspect you will be building your own enclosures and are handy).

Low bass ----- 2242-based Bertha subwoofer with Levan extensions (you need to build them)
Bass ----- 2225/2226-based 4520 scoops (used scoops are dirt cheap)
Low mid ----- 2225/2226-based 4560 (used enclosures are dirt cheap)
Mid ----- 2246 on 2350 long throw horns (very cheap too)
High ----- 2405 Ultra high frequencies

[louped garouv]

"berthas" are dual 18s per cabinet, correct?

[Lee in Montreal]

"berthas" are dual 18s per cabinet, correct?

Correct. And a modular design. The horn itself is an add-on. So moving them around is not that hard ;-)





Bertha and Waldorf.


If making a big Bertha is not a possiblity, then I would built two Waldorfs with four 2242

Also Theriam, if you don't already have purchased your 2242, may I suggest you purchase good used 2240s instead as they go lower by at least 5Hz and are dirt cheap. You can buy them for around $250 a pair on original JBL cones. Expect $500 for four drivers, which is less tha one single 2242... Build scoops with them and feel the thump. In each enclosure, one drivers can do 25Hz to 120Hz while the other does 25Hz to 50Hz. For really high SPL, then build four Waldorf/4520 (with eight 2240).

[Eaulive]

If making a big Bertha is not a possiblity, then I would built two Waldorfs with four 2242

The Waldorf is a dual 18???

[Lee in Montreal]

The Waldorf is a dual 18???

Obviously not, but they can be adapted to the better 18" 2240 just like the 4520 was also adapted for 18" 2240. 15" driver are great, but an 18" is better.

[louped garouv]

Obviously not, but they can be adapted to the better 18" 2240 just like the 4520 was also adapted for 18" 2240. 15" driver are great, but an 18" is better.

and the waldorf is based on the Jensen Imperial, right?

[Lee in Montreal]

and the waldorf is based on the Jensen Imperial, right?

Correct. With a bigger rear chamber and about the same horn length. But much, much simpler path, which avoids a lot of nulls. The Jensen/Waldorf were a great design.

[Lee in Montreal]

and the waldorf is based on the Jensen Imperial, right?

http://www.myspace.com/soundmanshort...-30-08/2305250

[reVintage]

Correct. With a bigger rear chamber and about the same horn length. But much, much simpler path, which avoids a lot of nulls. The Jensen/Waldorf were a great design.

Hey Lee,

Would you mind helping us with the drawing/plan? Or is this the original:

http://www.audioheritage.org/vbullet...l=1#post316853

A little confused if it is, as the chamber looks smaller than Imperials.

[Lee in Montreal]

Hey Lee,

Would you mind helping us with the drawing/plan? Or is this the original:

http://www.audioheritage.org/vbullet...l=1#post316853

A little confused if it is, as the chamber looks smaller than Imperials.

Here's the original design.
http://www.dcaudiodiy.com/jensen_imperial/page_11.jpg

I woud be very interested in developping that project. The drawing you linked is an old version. Since then I have slightly modified the upper right corner to a rounder shape to avoid any reflection. I guess it will take a few modelizations until the optimal shape is found. Or an original Waldorf to take measures from...

Differences could be throat and back chamber volume.

[reVintage]

Hi again Lee,

Thanks! I know the original Imperial very well and have the plans, never heard of the Jensen/Waldorf though. Same, same?

[theriam]

how many folks generally gather for these events?

and is the entire space used as the main listening area,
or is the space used in fragments?

bar area, seating, dining, "dance floor", etc?

We usually see between 100 to 200 people, depending on the event.

Yes, the entire space would be the listening area and is wide open. The dance floor starts out as a 30 'x 30' area but takes over the entire floor late into the night!