4343 Owner's Manual for bi-amp beginner.

[Steve K]

I would appreciate it if somebody can post a copy of the 4343B owner's manual, as I'm looking for information on bi-amping my newly acquired pair (owned a pair of L220 before this).
I presently drive them with a Mac 6900 integrated, and although pretty much satisfied with the sound coming out of the system, I feel that bi-amping could improve it in terms of more clarity in the mid thru high frequencies, and a more tauter, cleaner bass. What other equipments do I need to get to build a low budget bi-amped 4343 system besides the integrated amp I've already got? What other factors should I be aware of?
Any advice/suggestions are truly welcome. Thanks!

Steve

[Ian Mackenzie]

Hi Steve,

Welcome,

Your sure going to have some fun bi amping your 4343's.

There are a number of factors to be aware of and much of this information can be gathered from many valuable threads using the serach.

I am not aware of a manual for the 4343.

Ian

[Ian Mackenzie]

Steve,

.I'll post a link to the JBL schematic of the 4343 here:

http://www.jblproservice.com/pdf/Network%20Schematics/3143%20Network.pdf

There are a number of low cost improvements that can be done. Some of the links are below.

There are many other threads with valuable information on getting the best out of your 4343's so enjoy browsing the forums.

http://www.audioheritage.org/vbulletin/showpost.php?p=69827&postcount=123

http://www.audioheritage.org/vbulletin/showpost.php?p=69830&postcount=124

http://www.audioheritage.org/vbulletin/showpost.php?p=69836&postcount=127


http://www.audioheritage.org/vbulletin/showpost.php?
p=69854&postcount=133


Here is a link to the JBL 5235 manual which thoroughly describes bi amping.

http://www.jblproservice.com/pdf/Vintage%20JBL-UREI%20Electronics/JBL-5235%20manual.pdf

Nice to see the Lansing Heritage Forums reaches Japan.

Please let me know if we can be of any further assistance.

regards

Ian

[porschedpm]

Here's a copy of the 4343 brochure although there's not much on bi-amping in there:

http://www.lansingheritage.org/html/jbl/specs/pro-speakers/1977-4343.htm

Here's a generic article on the basics of biamping:

http://sound.westhost.com/bi-amp.htm#elect_xovers


I would suggest you approach bi-amping the 4343B monitors with the thought that bi-amping can improve your system but it's not guaranteed. In other words, as you add different components, be prepared to critically listen to your system with and without bi-amping to determine what sounds better to you. In my own case, I first bi-amped my 4343B's well over a year ago. I was using a Mac MC-150 (150w/ch) and a Pass X250 (250w/ch) amp. For the active xover I was using an Ashly XR1001. I thought it all sounded great and was an improvement over the the non-biamped set up. Then another LH forum member dared me to try my system non-biamped running thru just the 250w/ch amp. What I found was that I lost a little bit in bass authority and definition, but it was more than made up by the improvement in the clarity and detail in the mids and highs. What I found was that the active xover can either make or break your bi-amped set up. I'm convinced that bi-amping is certainly not the cheapest way to go and if you try to economize too much, and introduce a weak link into the system, you may be better off not bi-amping at all. Ultimately I believe bi-amping is the best way for the large format studio monitors, but it takes a lot of adjusting and comparison listening to really get it right.

[Steve K]

Thank you to both Ian and porschedpm for your informative replies.

What I'm aiming for is to have more clarity and definition in the vocal range, as well as more delineation when playing sources with broader range - i.e. Marty Paich orchestra versus a piano trio. I don't know, but it could be a number of reasons why my 4343 seems to sound a bit muddled in the mid to low-highs to me. For one it could be the room acoustics, all wooded floors and a high arched ceiling (all using pine wood which is relatively soft.) When directly placed on the floor the bass sounded too boomy and smeared the total sound. So I placed each of the 4343 on a pair of cast iron bases that lift the speakers about 7 inches. They then are placed on an inch thick MDF type 2' x 2' board over the floor to add mass to the floor. This defined the bass and the highs sounded more forthright, and the mids to low highs definitely improved, but still they aren't as clean as I feel they should be. It could be the electronics, too, for both my MacIntosh integrated and Linn Ikemi CD player may not be ideal for giving 'crystalline' sound as I understand it. But I'm not ready to swap these for other systems yet as I think that they do deliver very musical sounds, and they worked fine when I had the L100 and L220 before I 'moved up' to the 4343s.

Anyway, I'm enjoying this puzzle very much, and it makes life a bit more enjoyable.

Thanks again!
Steve

[morbo!]

maybe some rugs or tapestry`s hanging behind your listening position

[Ian Mackenzie]

Steve,

In my experience bi amping* will clean up the muddled sound you speak of and add definition to the bass.

Tehnically, the issue is the choke in series and large capacitor in parrellel with the woofer and large capacitor in series with the mid cone.(refer to 3143 crossover schematic)

I noticed siginificantly improved transparency and delineation of vocal harmonies and bass overtones when I biamped.

If you can hold off for a little while porschedpm will be reviewing a new active crossover on his 4343 - 4344 updated system. The details will be in the 4343 -4344 upgrade thread in the General forums.

The unit under development is pictured in the centre of the image below.


Ian


*The active bi amp crossover must be specific for this design and of the highest quality.