Custom JBL S1 Aquarius tri-amped design

[lattiboy]

Hey all,

I saw these pop up for sale locally and figured I had nothing else to do tonight, so I went and got them on a lark.

Holy Moses!

Apparently, these were gifts to a professor at University of Washington (the seller) decades ago. One of his students was getting his doctorate in acoustic engineering and these were a custom design. The seller couldn't remember any specifics, except that the two mid/tweeter combos were coated with "a very exotic material used in ultrasound technology".

I have never heard separation and sound stage like this in my life. I have a pair of Dahlquist DQ-20s which are no slouch in this department, but these are on another level. The instrumentation is highly separated, but the vocals appear to come from nowhere. As if there were an invisible center channel speaker plugging away.

At any rate, this is the best $50 I've spent in a very long time. Pictures and obligatory video:

Bonus points if you can tell me what the device hanging off the top speaker in the third picture is. Guessing a filter of some type?

 

[nedseg]

Waay cool find! Seems like its 'odd-duck JBL' week!
Sure am curious about those HF drivers & weird coatings. Too bad you didn't get more info on the back story.
What a neat find!

 

[toddalin]

Just looks like a resistor to me to reduce the volume to the top speaker a bit.

 

[Tom Brennan]

Sure am curious about those HF drivers & weird coatings. Too bad you didn't get more info on the back story.
What a neat find!

The tweeters appear to be Audax "direct drive" tweeters. They were very inexpensive but IMO sounded pretty good.

 

[bshorey]

Interesting find.

I'm curious, where does the tri amping come in? Looks like the speakers are all wired in parallel. It also looks like the pairs of speakers on the top each have their own midrange and tweeter, so driver placement across those looks interesting as well (and less than ideal?).

I'd be curious to learn more about these.

bs

 

[lattiboy]

Interesting find.

I'm curious, where does the tri amping come in? Looks like the speakers are all wired in parallel. It also looks like the pairs of speakers on the top each have their own midrange and tweeter, so driver placement across those looks interesting as well (and less than ideal?).

I'd be curious to learn more about these.

bs

Tri amped was a poor choice of words. I suppose "bi-amped x 1.5" would be better?

A lot of people have said I should flip the top speaker, and based on every other speaker I own this seems correct, but they sound so good I'm not in a rush to mess with them.

I honestly wish I had a better mic so I could convey how impressive the imaging is. It's frustrating, as I've been A/Bing them with my DQ-20s and they actually surpass them in some respects. Obviously the DQ-20s have a fuller sound and slightly wider sweet spot, but not by a ton.

Perhaps there is some other dark magic at play here I don't understand?

 

[bshorey]

Tri amped was a poor choice of words. I suppose "bi-amped x 1.5" would be better?

A lot of people have said I should flip the top speaker, and based on every other speaker I own this seems correct, but they sound so good I'm not in a rush to mess with them.

I honestly wish I had a better mic so I could convey how impressive the imaging is. It's frustrating, as I've been A/Bing them with my DQ-20s and they actually surpass them in some respects. Obviously the DQ-20s have a fuller sound and slightly wider sweet spot, but not by a ton.

Perhaps there is some other dark magic at play here I don't understand?

Not sure what 'biamped x 1.5" means, you're either running one, two, or three amps, right? Looking at the wiring, is there an active crossover between the bass modules and the mid/tweeter modules?

It might be worth trying to flip the top speaker, who knows, they might sound even better. It would seem like tweeter/mid/tweeter/mid would have an adverse effect on imaging, but if they work well that way, then who knows?

bs