Nice post, but for the original originals, I'll stick with "yuck".
I don't know about your modified version, but not only was the original difficult to listen to, they didn't image worth a damn. The speakers never disappeared; even my Audioengine things do that.
I bought my L100a speakers in 1973. They were part of my first stereo: an AR-Xa turntable, Shure M91 cartridge, a Marantz 2230 receiver, and the L100s. I was looking to buy Advent speakers, but I was in the Navy, and the only US-made speaker the European military exchanges carried was the JBLs. The other speakers they sold were various good looking but poor sounding Japanese-made speakers, Sansui, Pioneer, etc. So I sprung for the expensive JBLs. I kept that stereo for 27 years, with the addition of a cassette recorder, and later a VCR. In 2000 I got my first AVR and DVD player, keeping the JBLs and adding NHT center and surround speakers. After replacing the JBL's crossovers in 2004, I retired them completely in 2007, replacing them with Salk SongTowers. I'd sell them, but most people looking for L100s are scared off by the much improved crossover.
I got quite used to the JBL's sound, and kept them, mainly because I had a wife, 2 kids, a mortgage, and a very demanding job. But I have to agree with Irv. The L100s had 3 major flaws:
- Exaggerated bass, but not as bloated as the bass of many other speakers from the 70s or 80s.
- An rising response as frequency increased, leading to an overall bright & forward sound.
- A big ugly looking & sounding peak at 6-7 kHz, caused by break-up of the mid-range; combined with the lack of a proper mid-range band-pass filter; interference by both the woofer & tweeter, which both lacked any low-pass filter. All of that was made worse by poor placement of the mid-range driver relative to the tweeter and woofer on the front baffle.
The only thing I'll differ with Irv is his comment about imaging. At low to medium volumes the L100s did not cast an image. Their sound came entirely from within the cabinet. At loud volumes, this changed for the better. They could create outside-the-box images, but it required playing them loud. (Of course, that also depended heavily on the recording quality. Most vinyl LPs had a form of analog compression allowing 20 minutes of music per side, while preventing the pick-up needle from jumping out of the record's groves from bass vibrations. In general, this compression worked against good imaging.)
When I first took them to Dennis Murphy, I described their imaging when loud as one aspect of those speakers I really liked. He assured me not to worry, when his new crossover was finished they would create images much better. He wasn't wrong. Most of Dennis's designs, both DIY or commercial, are significantly better at imaging. He really does understand how to achieve that.
