4343 VS 4345 network?

[Bill Shenefelt]

Hi Bill,

- Here are the two schematics for the networks that I previously mentioned .

- It would be constructive to compare your 4-way networks to this N3143 network & then report back any deviations which might have been made.
( There's a possibility that JBL had you build a different network . )

I have the same as the 3143 you linked (less the 15 inch lo pass section up thru the 52uF input to the upper pass.) I enter at the 1.7mh coil. They sent me that schematic to assemble the parts they sold me. Now I need to update the caps and resistors in the MF. HF and UHF sections I have. What type caps are the 4, 13.5 and 20uF. Look like a wax in a paper cylinder.

[Chas]

What type caps are the 4, 13.5 and 20uF. Look like a wax in a paper cylinder.

Bill, I think the original JBL OEM caps were mylar back then.

[Bill Shenefelt]

[quote=Earl K;156734]

Hi Bill

BTW; nice woodgrain from what I can see .

I ordered ClarityCap SA for all crossover caps adding a 9500 pF ppolystyrene jumpers to all and Dayton .47 (to add the .5 on the one cap, 0.1 for two others and .01 polypropylene jumpers for all. Also using Mills resistors. I am just going with the 4343 stock values, JBL inductors and schematic. To properly space the 10 and 15 inch driver baffle positions, I can just flip the bass box cabinet upside down. That will give me real close to the 18 inch JBL spacing for these two drivers (but will move the large port nearer to the floor). I may also add some width to the baffle of the 10 inch and horn to simulate the 25 inch width of the JBL cabinet. Don't want to get into any reconing or changing coils. For info, the veneer on the faces of all my cabinets is straight grain walnut with all end surfaces done in walnut burl or crotch. All heavily tung oiled not coated with any kind of polymer. The speaakers and wall enclosure for the electronics is done the same including the inner alcove for the sota saphire table. Kind of gives a neat "hogged out of a log" look. Boxes are 7/8 inch high density cabinet grade particle board glued and screwed to 2 by 2 inch white poplar frames and bracing. The bass cabinet is 6 cu ft as opposed to the 5.5 of the 4343 (they gave up half a cu ft for the 10 inch which I did not have to do)
Now all I have to do is wait for parts including the 3 way Marchand active xover. Once all balanced I may replace the JBL volume pots with fixed resistors. I'm not sure if I am going to do more than the 300 cps point but will have the option of going active with the 9k to the slot radiator with delay or a 1200 for the whole horn set. I'll need some switches for that unless I rewire things though. I did have it done that way before using a 240 McIntosh tube amp for the horns. Thought it might make them a bit smoother. Thanks to you and all, I think I am on my way to a nice sounding system. Once all is done, I will post some photo links. Should keep me busy for a few weeks though since the MArchand is a partial kit and I have a ton of tropical fish work to keep going on the 160 tanks in the basement.
Again, thanks all.

[speakerdave]

Heather-

I see you have the 2308 upside down (I expect you know this). Would be interested to know why this is your preference.

David

[hjames]

Heather-
I see you have the 2308 upside down (I expect you know this). Would be interested to know why this is your preference.
David

Well- from reading a white paper someone linked here a few weeks back, it seems that the lens purpose is to slightly delay the horn signal in relation to the woofer, so when they designed for it, its recommended to use it. It seems the lenses don't "bend" the signal, they merely offset it up or down by the height of the lens (which is related to the wavelength). See - http://www.lansingheritage.org/image...ens/page02.jpg

On exiting the lens it basically travels straight forward from that point.

So, from our sitting position on the sofa, the lens shifted down would put the signal at just about knee level, shifting it up puts it close to chin level.
If I used the lens in a "normal" slant down mode, I could compensate by putting an short platform under the cabinet to lift the system say - about a foot. But then the bass would diminish from such a change.

I had confirmation of that when I used the wheeled skids (usually used for plants) under the 4320 boxes previously. When I put the components in the L200 cabinets and put them flat on the floor, I had a greatly improved bass response.

It seems to work fine for us.

Currently in full passives mode using 2215/2420/2405 and 3133 equiv network ... (awaiting new receiver and my own JBL M552 active crossover).
(24 sounded really good tonight, as did the new Casino Royale DVD we watched Sunday night, and all the music I've been playing lately.)

[ivica]

[QUOTE]

Well- from reading a white paper someone linked here a few weeks back, it seems that the lens purpose is to slightly delay the horn signal in relation to the woofer, so when they designed for it, its recommended to use it. It seems the lenses don't "bend" the signal, they merely offset it up or down by the height of the lens (which is related to the wavelength). See - http://www.lansingheritage.org/image...ens/page02.jpg

On exiting the lens it basically travels straight forward from that point.

The point is "V" shape 'opening' on the lenses, so the sound from middle of "V" has less delay the the sound from 'peripheral part' of "V", and all together produce "bending" of sound 'front' so the dispersion of the sound instead, of say +/- 25 deg, rises almost double, say +/- 45 deg.

[hjames]

And, of course, since my 2007 post below, I gutted the upper cabinet, mounted the 2405 slot into the L200 cabinet, put a 2441 driver and walnut horn on top, and then moved that 3-way speaker to another room when I got a pair of actual 4341 monitors to take the place of the hybrids ...

But I'm running them with the original 3141 crossovers, that I really should replace with a pair of replacement 3145-equivalent crossovers! I just have to buy parts and build them!