restoration 4350

[traveler]

I would like to place the JBL 4350 on their sides due to space restriction. Will this have any affect on their performance and can I relocate the ring radiator so I can accommodate the lens diffusor. Any help would be greatly appreciated.

[ngccglp]

Hi,

I would advise against doing this as this permanent mod would devalue the speakers.

The lens helps with the horizontal dispersion of the 2440. The vertical dispersion is narrower. I would toe in the 4350 so as to compensate for the narrower dispersion of the horn lens when in vertical orientation.

You could rotate the 2405 though to have the slot in the vertical orientation.

I too wanted to put the 4350 on its side but finally decided to just use it as intended in the horizontal position. They were side by side and I had the 2405 on the outside. Still sounded awesome.

[macaroonie]

Try it.

[DogBox]

Saeman came up with this: http://www.audioheritage.org/vbulletin/showthread.php?6684-JBL-NOT!!-DIY-4351-Studio-Monitor

Does require a bit of carpentry though...!!!




DogBox

[sparky2]

I have an idea for using the 4350 on its side. Move the ring radiator to the other blanked-off location, turing it 90 degrees. The blank-off plates usually come off on other models simply by removing 4 screws inside. Then there will be room to rotate the diffuser lens by 90 degrees in the original horn position, as well, using two additional pieces of stick-on Velcro. Also point the diffuser vanes up away from the floor. This should allow you to get good horizontal high frequency dispersion with the cabinet rotated 90 degrees, resting on its side with the ring radiator at the top and the horn with the diffuser on the bottom with the diffuser vanes pointing up. You will not need to modify the cabinet, and would only compromise performance by having the diffuser on the bottom.

[sparky2]

Correcting my previous post, the tweeter is a 2405 slot-type Ultra-High Frequency Transducer, not a ring radiator.

[grumpy]

No correction needed. Still a ring radiator, just configured with a diffraction slot exit.

[sparky2]

Interesting. You just taught me something. Thanks. The slot must give the tweeter good horizontal dispersion by diffraction.

[ivica]

Interesting. You just taught me something. Thanks. The slot must give the tweeter good horizontal dispersion by diffraction.

Regards
ivica

[traveler]

This is my first time to be part of a forum like this one and all I can say is that I appreciate the time and effort that everyone has shown in their answers. Regarding Sparky2 idea-with the horn in a different plane to the slot radiator--would there be a compromise in the performance or as in real life living room --little difference? Thanks again everyone.

[traveler]

I have spent quite a bit of time to work out two concerns about the restoration of my speakers. One is just where can I buy the blue grill cloth and the other is the colour number of the blue paint. Being in Australia something it is hard getting specific things especially when we are going fast, riding on our favourite kangaroo. There is a company in Japan but I am not sure if they will just supply as they specialise in the full restoration of top end speakers. Regards.

[57BELAIRE]

this thread could be helpful....good luck with your project!http://www.audioheritage.org/vbulletin/showthread.php?33007-JBL-Blue-Baffle-Paint&highlight=blue+paint

[sparky2]

To: Traveler

I typed you an earlier response, but it bombed. Anyway, the priority is to have the highest frequency driver, in this case the ring radiator, in the highest position, near level with the listener's ear, because of the increasing directionality with higher frequency. You can just experiment wth the 2420 (or other) horn-with-lens in the top and bottom positions, with the ring radiator disconnected or covered with tape. If you hear a major difference, there is some compromise, but you want to save space in the room by placing the cabinet on it's short-axis side...So compromises are compromises. There is no free-lunch. I would also try this with the ring radiator not blocked, and you may not notice much difference. You can always do tests with a good reference microphone and SPL meter, but my opinion is that the listening test rules. Modification of the cabinet to keep both high-frequency drivers on top may be an option, but I know that we are all trying to keep the old units as near to JBL original as possible. I may invert a 4320 I just restored for an old friend before he picks it up and listen to it to test this idea. Please let me know how your project progresses. This is the fun of this forum, sharing ideas and experiences! -sparky2-

[traveler]

With the restoration nearing completion I am now wondering what to use with these speakers as a "centre" and "rear" speaker. I assume that most surround amplifiers will be ok as I will use my block amps to drive the 4350 and the built in amps of the receiver for the rest. Any experience from the group would be appreciated. Thankyou.

[more10]

:useless:

[traveler]

Thankyou for the not so helpful reply. I am a volunteer teacher in Fiji and the restoration is happening in Australia so that is why I request help from others that have more knowledge than myself. If you fit this criteria then please help in regards to my questions. Regards.