Hi I read the recent thread Quick and Dirty 4430 'shttp://audioheritage.org/vbulletin/showthread.php?t=3838'
thread with great interest. However as a JBL novice it has raised some questions that may be found in a JBL tech note etc on the evolution of their xovers etc. Can anyone help me locate this info?

Anyway my specific questions are as follows

1. There appear to be three series of Pro passive xovers
(a) 3105, 3106, 3110, 3115 & 3120

(b) the "A" models 3110A, 3115A, 3120A and

(c) 3150, 3160, 3180, 3152, 3182 etc

My understanding is that (a) are for use with pre CD horns and that (b) have a HF boost option which I guess is for some CD horns (eg 2360, 2380)

I have no real understanding of what (c) can be used for other than that they appear to have higher power ratings and more tap options.

I would appreciate advice on the suitability of all three types for home use. It can be taken as granted that I understand the need for differing freq xover points and therefore different xovers depending on which driver and horn combination is used. I have some CD horns I am currently using (2380A) but also some earlier 2" (eg 2390 and 2397 Smith horns) and 1" (2392) that I want to play with.

2. Would also appreciate some advice on the evolution of the JBL active xovers.

(a) What is the essential difference between the 5234 and 5235 xovers?
Can they both use the same card plug ins? and

(b) Are the later M552/ M553 significantly better? I am aware these have options for CD horns (2360 & 2380) but I noted from the earlier thread these options are not considered ideal for 2344.

Would also appreciate any insights into earlier or later JBL active xovers other than the digital ones which are really beyond, and in a different ball park to, the above.

3. Running the risk of asking too much in one post, I would really appreciate advice on the efficiency of the earlier pre CD 2" (eg 2390, 2397 ) and 1" (2392 etc) mid difraction horns say for simplicity assuming they were all driven with a 2440, or a 2420 (in the case of the 1" ) horns. Believe I read in an earlier post that they were all about 108 dB/1W/1m. Also do any of these require any equalisation?

TIA

Aust-ted