4333A....Can I Improve Them?

[Jeff M]

I am pretty happy with my 4333A's as they have great sound, but have been wondering if ther is anything that I can do to improve them in any way? I know it is a loaded question, but I would like to hear any suggestions. They seem to sound better when I couple them with my L-166's and I was looking for a way to get around this(living room space is a factor:blink: )Maybe crossover mods? Should I stay with the mid horns? Also, does anyone use the expensive supertweeters available now?

[boputnam]

...They seem to sound better when I couple them with my L-166's...Describe how.

[speakerdave]

As with all well-engineered speakers, the 4333A is the product of a set of compromises within a preset overall configuration and price point. Besides the usual compromises involved in designing driver parameters, crossover points, etc, the known compromises on price in the 4333A as well as other 43XX speakers include the input posts, the switches for biamping, the level control L-pads for the mid and tweet. Subsequent engineering by JBL has created the charge-coupled crossover. A circuit to use for creating a charge-coupled replacement crossover for this speaker has been published in the forums.

Some have reconed the 2231A with a 2235 kit or replaced the woofer with a 2235H and have appreciated the improved bass, but others, including me, have noticed a problem in the midrange with that change. I think I know what the problem is, but have not had time to check out my idea, so I will not pass it on at this point.

When I first got my 4333A's I ran them with a pair of 2225H's while the 2231A's were being refoamed. That woofer has a lot more punch in that enclosure than the 2231/2235, but the deep bass was missing, and the blending with the midrange did not work well.

Most would admit that the ultimate upgrade for a 4333A would be to somehow make it into a 4343, but please don't let my little hyperbole mislead you into carving up the cabinet.

I think the things to appreciate about the 4333A as-is are the overall balanced sound, the liveliness of the presentation and the smooth treble. It's a plenty-good speaker as-is.

The first and easiest improvement would be to raise it off the floor at least 8 or 10 inches to eliminate that little bump in the bass. Then biamp, with an 800 cycle low pass on the woofer; you don't need a high pass on the treble because that part of the crossover/filter stays in the circuit, as does the zobel on the woofer. After that you could build a charge-coupled crossover and redo the input panel. If your speakers are in "collectable" condition, do these changes so they can be reversed. Some would say to "upgrade" the diaphragm in the 2420 to the 2421 type. I have not done it because I'm skeptical, and I don't think it's worth my $400 to find out who's right.

David