music, guitars & other obsessions

New Speakers – JBL 4730A

[Update 7/31/2014]

After listening to the speakers for a few days, I could not stand them! So I had to take them down – the frequency response was just too far off for the EQ to work out the kinks. They were very hard to listen to, sigh… So there are few things that I can try to address the problem:

  1. re-work the passive crossover to smooth out the response – however I don’t think this is a trivial problem and would require a lot of measurements and component fine-adjustments;
  2. re-wire the speakers for bi-amping with electronic crossover (via foobar2000’s DSP) – this probably is a bit easier to do than the passive crossover, since I think a lot of the problem were due to the poor interaction between the drivers – which could be potentially dialed out with DSP;
  3. replace either the woofers or the mid-woofers – but this kind of defeat the purpose of having “JBL” speakers;
  4. get rid of the bullet tweeter – I think they are too directional in my small space;
  5. a combination of 3 & 4 above.

In any case, the poor frequency response was not easily dealt with equalization as I originally thought, oh well, worst case, I can always part out the drivers, which are actually worth quite a few dollars… seems a shame though.

===

Scored a pair of vintage JBL PA speakers yesterday, the JBL 4730A is a 3-way design with 2226H 15″ woofer, 2118H 8″ mid-woofer and the 2402 bullet tweeter replacing the original 2403 super tweeter with bi-radial horn in the original design.

4730A With & Without Grill

4730A With & Without Grill

The first impression upon listening to them was that these speakers were too bright, a quick check of the data sheets of the tweeters revealed the reason why – the 2402 was 5dB more sensitive than the 2403, so the HF response was drastically exaggerated from about 2.5kHz and up.

2402 Bullet Super Tweeter

2402 Bullet Super Tweeter

So right off the bat, the crossover needs to be modified a bit to tame the 2402.  In the meantime, I am just using the built-in EQ of the audio player; which reveal another thing, that these speakers were very analytical, i.e., they reveal the recording – warts and all – many recordings were just poorly done and very hard to listen to without some equalization so forget about “natural reproduction”…

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