The JBL 4345 Club

[Ian Mackenzie]

Zilch,

When are you going to show us your new Threads??

[Ian Mackenzie]

[quote=Tom Loizeaux]

"I can't belive all the interest in this 30 year old system."

Greg, Thanks gain for your post on the 4345.

Though the 4345 is popular with some members here, and the 4344 is the latest version (US) of the 434X series, the 4343 seems to be the most prevalent version of these great 434X series studio monitors. Since so many of us are using, restoring and refining 4343s, I wonder if you would comment on this 43 series in terms of how they differ sonically from the character and nuances of the 4345s you commented on earlier.
Specifically:
Are the 15" woofers better suited to the 10s and how do the 2231, 2231H and 2235Hs compare in this monitor. (Bi-amping a given)
Can you comment on the 2121 verses the 2122H in this application and how the inverted dust cap contributes.
And finally, which compression driver/ diaphragm fits into this 4-way configuration best?

There has been a great deal of interest and discussion on these points, and much good information expressed, but your comments are highly valued, for obvious reasons, and would make a great contribution to this Forum.

Thanks again for all your efforts!

Tom

P.S. I love my 4343s

Hi Tom,

About the 10 inch matching/mating I think its fair to say that you need to watch boundary effects with the larger woofer in the 4345 more so than the 4343 to ensure the system does not bloom in the bass and muddy the integration with the mid cone. This has been discussed elsewhere by Giskard and Greg.

There is also factual information on the 2121 vs 2122 in various threads posted by Giskard if you care to do a search.

You may wish to pm porschedpm who as I understand it has completed all the driver and crossover upgrades from the 4343 to 4344 for his comments on the subjective differences.

Since the crossover and Mid & Hf components were lifted from the 4345 (by another engineer) and used for the 4344 it is reasonable to assume they are tonally very similar in that regard (however the placement of the 15 inch driver in the 4344 was apparently not ideal).

Greg designed the 2245H and tuned the enclosure empirically for the 4345 system. Some details of this are given in Greg's earlier post.

As I understand it the 4343 was designed by another engineer(s).

Don may may be able to document more on this at a later stage.

Ian

[4313B]

As I understand it the 4343 and 2231/2235H was designed by another engineer(s).

Don may may be able to document more on this at a later stage.

Don will have to elaborate. Greg has said that he didn't do the 4343 several times over the years. Mark Gander did the 136H/2231H and Greg did the LE14H-1 and 2235H, as well as the 2245H. I have no idea who did the 2121, never asked, but Greg did the 2122H.

[Ian Mackenzie]

Thanks for the tip. My settings are close to that. My room is different from yours, probably smaller and better damped.


Absolutely!

Chas, Ken, schloerch and others, thank you for the kind words. I will be reporting on progress when I can.

David

David,

Can you please post a picture?

[Ian Mackenzie]

I am proposing to build a black magic box for the 4345.

Inside it will have a dedicated active crossover for the woofer/midrange and a high pass filter for the slot. There will be a charge coupled passive network and a small chip amp for the slot.

It may sound complicated but with some thought I think it will be fairly straight forward.

I will post details as the concept develops

Ian

[Robh3606]

Now that sounds like a good idea! Combines several significant changes into one upgrade.

Rob

[Ian Mackenzie]

Now that sounds like a good idea! Combines several significant changes into one upgrade.

Rob

No doubt it could be applied to the 4344/4343.

My last back boxes.

The key will be to bring together and combine the essentials.

Pending space and budget I might add an X Aleph >75 watts for the mid + horn and and Mini Aleph <10 watts for the Slot for my personal version.

Ian

[Ducatista47]

I am proposing to build a black magic box for the 4345.

I will post details as the concept develops

Ian

You have my attention, Ian. I wish I knew enough to contibute.

Clark in Peoria

[speakerdave]

David,

Can you please post a picture?

Of the settings? Tomorrow.

I've moved the speakers into the larger room (only Widget has seen it, I think), and that has had a very rewarding result. The speakers are not tracking, so tomorrow I may steal the time to bring my audio generator in and juggle tonality and tracking for a while.

David

[boputnam]

The speakers are not tracking...

This syntax is new to me. What are you describing...?

[speakerdave]

This syntax is new to me. What are you describing...?

All fixed. I hooked up my Krohn-Hite, set the preamp to mono and had my son turn the dial slowly, calling out the hundreds while I sat in the focus. It only took a few minutes, and I had them climbing straight up. Now when Anne-Sophie Mutter plays, the only movement in the imaging is her body sway. Yesterday she was walking back and forth behind the conductor as she went up and down the scales. Part of the problem was differential absorption and reflection of the upper mids in the fields of the two speakers. I usually like to sit back farther than the point of best focus because I like the blended sound more than the sharp imaging. So,when I sat on focus I found the tracking was better than I had thought and I only needed to make a minor adjustment to one level control.

David

[grumpy]

I'm thinkin' amplitude balance (L/R level tracking) vs. frequency was the point. -grumpy

[speakerdave]

I'm thinkin' amplitude balance (L/R level tracking) vs. frequency was the point. -grumpy

What he said.

[speakerdave]

Here they are in their new spot.

[Zilch]

I like the blended sound more than the sharp imaging.

Rob's kinda saying similar over in "PT Waveguides."

Something more "natural" about a slighly diffused (defocused) image, is how I read it.

Also, somewhat more comfortable listening without a head brace....