Upgrading an L-200

[witoman]

I have a very good working pair of L-200's, but after reading this and other forums, I decided to experiment with upgrading it. I have purchased:

- a pair of 136A woofers that the seller said came from L-300's,

- a pair of 2405 slot drivers, and

- a BBE Max-X3 2-way stereo electronic crossover.

I like to replace the L-200's LE-15A woofers with the 136A's, keep the LE85 driver with the H91/L91 horn/lens combo and then add the 2405's in an outboard box made especially for them.

I would use the crossover to feed the upgraded L-200's frequencies below say 7KHz (I would use the single L-200 inputs, not the bi-amp ones), and feed the higher frequencies to the 2405's. The crossover has separate gain controls for the high and low frequencies, so I can match the efficencies of the L-200 and 2405.

I have some questions:

1) Am I setting myself up for disaster, or is this a good plan?

2) I've never pulled the drivers out of the L-200 cabinent before. To remove the LE-15A, do I just unscrew the 8 bolts around the periphery of the surround and then pull the speaker outwards, or do I need to go into the back of the cabinent first?

3) I see that the L-300 has only one port and the L-200 has two. Should I stop up one of the L-200 ports?

Thanks

[duaneage]

I would run the two woofers througha box design program first and see what it says. Boxplot is a free progam that let's you see what changes in volume and tuning do and the price is right, just download it from here

http://www.diamondcut.com/boxplot.htm

and see what will happen before you take things apart. The driver TS parameters are available from the JBLPRO.com website under technical library and driver parameters/

My gut instinct tells me that you would be better off leaving the 200s alone and building new cabinets for the 136a woofers.

[speakerdave]

Hi,

I think the L300, like my 4333A's, crosses over at 800 Hz and therefore uses a different horn, the longer H92/2312. Total depth may be too long for that cabinet, so if you are looking to be exactly like the L300, there's a problem. I also think, going from the LE15 to the 136 you may not be happy with the existing crossover frequency, because the 136 will not be as good up there as the LE15. You might consider just adding the super tweeter. Or you might consider building your own cabinets and selling these off. LE85's are not hard to find.

David

[Zilch]

Standard LF driver in L200 is LE15B (cloth surround), not LE15A (lansaloy surround), and the crossover frequency is 1200 Hz. I last calculated the internal volume as 4.9755 cuft. It' different every time I do it.

136A's will play nicely in that box with one of the ports closed for extended bass (~25 Hz), or both open for tighter, punchier bass (~35 Hz). I'm using 2235H's in them right now, with proprietary port closure technology so's I can choose bass tuning as desired.

You'll want to move the crossover frequency down to 800 Hz with, say, 3110 crossovers. The rear panel crossover cutout size is the same.

However, as stated above, if you're thinking L300, you'll not be fitting the longer horn in there unless you're willing to punch the LE85 out the back, a mess.

The long horn may be optimum, but JBL used the short one down to 500 Hz in the "legendary" S7 system.

L200B used the shorter horn crossed at 800 Hz with 136A woofers, and several members have successfully added 2405 UHF to them using 3106 crossovers. It can be cut into the baffle space above the present horn if you want to forego the external box.

There is no biamp input on L200 that I'm aware of, but you should be able to use your active crossover. Feed everything below 7 kHz to the 3110's, and the VHF to the 2405's.

The 8 bolts will remove the woofer, but it may require gentle persuasion to come free if it's not been removed before. Lay the cabinet on its back to work on it.

There's no "going into the back of the cabinet" option available.

See my avatar for an alternative formula for L200 upgrade if you want to get radical....

[witoman]

Thanks for the feedback. I've looked at the L-200's again and I see:

- The woofer does have the cloth, accordian style surround, so that makes it an LE 15B.

- I would use a GAS Grandson (40 wpc) amp to drive the 2405

- The L-200 crossover is an LX-16 which has three stereo sets of inputs, a) one marked "Input" which is the way that I have connected the speaker to the amp (a 200 wpc GAS Ampzilla, BTW), b) one marked "LF", and c) one marked "HF".

I am assuming that input option a) takes the full spectrum audio signal and splits it between the LE 15B and LE85 drivers at 1200 Hz and that b) and c) are for biamping with an external crossover and separate amps, i.e. the LCR passive crossover circuitry of the LX-16 would be bypassed.

I will have to live with the short 1200 Hz H91 horn and hope that the 136A can reach that last half octave between 800 and 1200 Hz.

An alternative is if the LX-16 crossover allows for biamping, then I can run two BBE Max-X3 electroinc crossovers in 3-way mono mode and cross the 136A at 800 Hz and the 2405 at 7KHz using the Max-X3's. I would have to run 3 amps. I have a GAS Son of Ampzilla (80 wpc) and a GAS Grandson (40 wpc) to do this so the amps will be of the same "family" of circuitry topology.

I will plug up one of the ports as I really do want lower extension. I'll let you know how things turn out.

[Zilch]

b) and c) are merely the wires going to the drivers. I you want to drive them directly, you have to disconnect the leads entirely from the crossover for use.

Trust the Zilchster on this, now: If you aren't going full active triamp, spend about $100 on eBay and get a pair of JBL 3110 (800 Hz) crossovers to replace the LX16's. You don't need 3110A's since you're using a separate tweeter.

A primary reason JBL used the LE15B instead of the extended bass LE15A or 136A in L200 was because they don't play well to 1200 Hz. 2235's don't even do it; that's why 2234H is the recommended replacement, and even that is a compromise. JBL abandoned the attempt soon thereafter.

Max recommended crossover frequency is 800 Hz:

http://www.lansingheritage.org/image...2231/page2.jpg

Note also, they soon published a mandatory modification for LX16, as well, to protect the LE85 drivers. The original L200 design was compromised in these several ways. Your upgrades will improve them substantially.

http://manuals.harman.com/JBL/HOM/Te.../L200%20ts.pdf

http://manuals.harman.com/JBL/HOM/Te...L200B%20ts.pdf

[My proprietary port closure devices are 4" plumber's test plugs from the hardware store. Don't tell anybody, tho.... ]