[Jazzman53]

Hello everyone,

On April 17-20 the first annual Jazzman SpeakerFest was held at my friend Stephan's farm, about 30 miles south of Newark, NJ. 

Attending were myself and five other Jazzman MkIII speaker owners, along with their wives.  This get-together and shootout were Stephan's brainchild, and it was so much fun we're considering making it an annual event to be held every April at Stephan's farm.

Most owners had me build their Jazzman MkIII ESLs but Stephan built his pair himself, from a cherry tree that he felled, and my CAD drawings.

In preparation for this event, Stephan had also spent many months researching and restoring an old defunct pair of Soundlab A1 speakers which he got for free because they were in such poor condition. 

Stephan unveiled the fully restored Soundlab A1's, minus grill covers, at the Fest, and we had a weekend listening session and shootout between the A1's and Jazzman MkIII's (see the photos below).

Stephan credits Dr. Roger West at Soundlab for much helpful advice on the restoration.  The Soundlab A1's have about six inches of span between wire supports, which is a bit excessive, whereas the newer Soundlab models corrected this flaw with stouter frames and much closer spans between the wire supports. 

Knowing this; Stephan modified his A1's by adding additional wire supports that he designed and 3D printed.

Dr. West donated several full-width sheets of 3-micron film for the diaphragms.  However, there's apparently a significant learning curve to  install 3-micron diaphragms on these huge speakers-- the thin film was so static-clingy and prone to tearing that Stephan gave up after several failed attempts used up all the 3-micron film, and he ended up splicing together two pieces of 25" 6-micron film for the diaphragms. Licron Crystal was used in lieu of the original conductive coating.

Stephan is quite the DIY'er-- he built a loft in his barn, and turned it into a dedicated man cave / audio listening room-- its acoustics are amazing.  In fact; I've never heard the Jazzman MkIII's sound so good as they do in Stephan's barn loft listening room.

Setups for the shootout:

1. Soundlab A1's powered by a Macintosh 352 amp (320 watts/ch @ 4Ohms).

2. Soundlab A1's (same amp) + a pair of separately powered RiPol subs.  A DBX Venu 360 DSP crossed the subs in and the A1's out at 80Hz.

3. Jazzman MkIII hybrid ESLs + RiPol subs, all driven by a 6-channel, 200W/Ch ATI amp, using a DBX Venu 360 DSP with symmetric 48db/octave crossoves @ 80Hz & 265Hz.

My impressions:
Since the Jazzman MkIII's are my design I would prefer to recuse myself from commenting on the shootout but I'm obliged to report the consensus opinion.

Setup 1 impressions:
The Soundlab A1's sounded fabulous. To say that their sound stage is huge is an understatement.  They are exquisitely articulate and their bass response was the best I've heard in a full range ESL-- in fact; we all agreed that subs really are optional with the big Soundlabs.  The highs were pristine and present across the full sound stage.  The upper mids were a bit bright (in your face) for my taste but that could probably be corrected with an EQ.  We also noticed that the Soundlabs soak up amp power like a sponge; almost pegging the VU meters on the big MAC amp.

The wives preemptively shot down any plans of having such large speakers in their living rooms, and their husbands wisely did not disagree.   

Setup 2 impressions:
With the A1's unloaded below 80Hz and the RiPol subs handling the bottom end, the bass was noticeably deeper and tighter.  Unloading them below 80Hz as we did freed-up some headroom and may partially account for why this setup sounded so much smoother and more at ease with the subs in play.  Everyone preferred this setup over setup #1.

Setup 3 impressions:
I think all of us were predisposed to believe the big Soundlab A1's, by virtue of their much larger radiating area, and rave reviews in the autio magazines, would easily outclass the smaller Jazzman MkIII's in almost every respect but that was not the case at all-- The Jazzman MkIII's filled the room with a more balanced and coherent sound than the A1's in setups 1 and 2. 

The MkIII's Eminence KappaLite 3012LF woofer, which is mounted on a modified-H open baffle, gave superior midbass punch, and its integration is so imperceptibly seamless that it sounds like a single driver that disappears in space.

Since I can't recuse myself, I almost hate to say it but... everyone agreed that the Jazzman MkIII's won the shootout; besting the restored Soundlab A1's.

Me with the Soundlab A1:


Restored Soundlab A1s:



Stephan & Me:



Stephan's self-built Jazzman MkIII's:



 

[FullRangeMan]

Wow fantastique event
Congratulations, nice photos also.

[Early B.]

Total awesomeness!

[mresseguie]

I'll bet that was a lot of fun! Good job, all!

[SteveFord]

You guys have some impressive skills, that's for sure.

I would have guessed wrong about the soundstage, too.

[Tyson]

I’m not surprised the narrower speaker images better.  I am surprised that the smaller speakers were able to scale and match the bigger speakers.  That is impressive.  Well done!!👍🏻

[Jazzman53]

I think the Soundlabs need a really big amp (500 watts/channel) because they pushed a potent Macintosh 352 chip amp to clipping when we cranked the volume. 

Full range ESLs like the big Soundlabs are very inefficient because their diaphragm-to-stator spacing (d/s) must be large enough to accommodate the diaphragm's greater X-max at bass frequencies.  The Soundlab's d/s is 5/32", whereas the hybrid Jazzman MkIII only needs 1/16" of d/s.

Doubling the d/s reduces the drive force by 400% so-- the 1/16" d/s is 600% more efficient than the 5/32" d/s for a given radiating area.  The Jazzman MkIII is smaller than the Soundlab A1 but it's not 600% smaller, which is why it can match and possibly play louder than the larger Soundlab. 

I would love to hear the Soundlabs powered by a pair of the MAC 352's bridged mono. 

One of the guest attendees talked me into selling the last remaining (seventh) pair of Jazzman MkIII's, which had been hording unused in a back room in my house since 2021.  There will only ever be seven pairs.

I returned home happy to know that the Jazzman MkIII performed so well against one of the finest speakers in the world but, after hearing how great they sound in Stephan's excellent loft, I'm now unhappy with my own listening room at home.   

[Don_S]

Jazzman53,

I do not doubt your experience with the McIntosh 352 but your comments on the power Sound Labs require is incorrect. I have driven my SLs to louder than I wanted for sustained listening with various amps (McIntosh, Boulder, and others) rated from 200wpc down to my current favorites, VAC Essence monoblocks rated at 85wpc. I never had any problems with clipping or running out of power.

Congratulations on making great speakers. I only want to make an important point. The Sound Labs used in your test were highly modified and somewhat dated. They are not representative of the best current Sound Labs can do.

[WGH]

I think the Soundlabs need a really big amp (500 watts/channel) because they pushed a potent Macintosh 352 chip amp to clipping when we cranked the volume.
 
I would love to hear the Soundlabs powered by a pair of the MAC 352's bridged mono. 

A pair of MAC MC830 monoblocks just appeared in my TMR newsletter. 480wpc @ 4 ohms for $6,499

https://tmraudio.com/products/mcintosh-mc830-monoblock-power-amplifier-pair?_kx=w-PA7mFcpYmiwsnSHPizII122O-genOhn4zOGfmr_tE.WBMz2Y

Great review BTW.

[Statman72]

Jazzman53,

I do not doubt your experience with the McIntosh 352 but your comments on the power Sound Labs require is incorrect. I have driven my SLs to louder than I wanted for sustained listening with various amps (McIntosh, Boulder, and others) rated from 200wpc down to my current favorites, VAC Essence monoblocks rated at 85wpc. I never had any problems with clipping or running out of power.

Congratulations on making great speakers. I only want to make an important point. The Sound Labs used in your test were highly modified and somewhat dated. They are not representative of the best current Sound Labs can do.

Update & additional info:  Since my initial post, two other SL rebuilders have told me that the older A1's are indeed more power-hungry than the newer SL models, irrespective of the modifications to Stephan's A1's used in the shootout. 

Efficiency improvements in newer SL's include irraditated-PVC insulated wire in the stators for better arc resistance/higher power handling, to accommodate higher ratio transformers providing greater drive voltage per watt of input power, and higher biasing voltage on the diaphragms.   

Efficiency in any ESL is predominantly determined by the diaphram-to-stator spacing (d/s) because the strength of the driving electrostatic force falls off non-linearly, per the inverse square law.  That is; doubling the d/s reduces output by a factor of four (or requires four times the input power to achieve the same SPL), and full-range ESLs require at least twice the d/s of a hybrid design to accommodate the greater diaphragm excursions for low bass.  Whereas higher drive and bias voltages increase SPL linearly (i.e. doubling the bias/drive voltages doubles SPL).   

Hence; a hybrid can be four times more efficient than a full range design, which is why the Jazzman MkIII's played louder, with less power input than the larger SL A1's in the shootout.