System #525 (DIY ESL)

[Jazzman53]

1. Member Name: Charlie Mimbs

2. Location: Savannah, GA (USA)

3. Speakers: DIY Hybrid Electrostats

4. Year - Cab/Frame built in 2008, newest panels in 2016

5. Mods/Changes:
- ESL panels upgraded with segmented wire stators
- Amps: Recapped / Service Bulletin upgrades /gold 5-way binding posts

6. Associated Electronics:

Source Components:
- Logitech Transporter
- Carver DTL-100 CDP
- Carver TX-11a Tuner

Preamp:
- Logitech Transporter
- Carver C1

Processors:
Behringer DEQ2496 EQ
Behringer DCX2496 Crossover

Amplifiers:
- Bob Carver Signature TFM-25's

Speakers:
- Homebuilt wire stator hybrid electrostats
- Homebuilt Ripol subs (Peerless SLS 12's)

Interconnects:
- Dayton Gold

Speaker Cables:
- Homebuilt cross-connected Belden coaxial

Rack:
Homebuilt red oak

7. Comments and/or stories about your Martin Logan experience:
I don't actually own any Martin Logan gear (yet) but auditioning a pair of ML Summits started my whole obsession with ESL's. I was immediately hooked by the ML's spooky coherence and clarity. After that, everything else was two Dixie cups and a string.

My first homebuilt ESL's had flat perf metal panels which gave great slam and imaging but beamed like crazy (head-in-a-vise). The next iteration eliminated the head-in-a-vise effect using electrically segmented welding rod stators with switch-selectable wide and narrow dispersion modes. These had a nice balanced sound but were visually just butt ugly. Finally, my newest panels are beautiful and more finely segmented to project a perfectly curved, lobe-free wave front using oak lattice supported wire stators that look and sound like fine musical instruments.

The segmented stators tailor dispersion somewhat like a Quad ESL 63, except where the 63's stators used concentric ring conductors driven by stepped-phase signals to emulate a point-source projecting a spherical wave front, my stators use symmetrically arrayed vertical wire groups driven by stepped-phase/stepped-frequency signals to emulate a line-source projecting a cylindrical wave front.
For details and build photos see my webpage: Jazzman's Electrostatic Loudspeaker Page

The rest of my gear is mostly vintage Bob Carver and even though I'm a dummy with electronics, I managed to learn enough to recap & refurbish my Carver amps, preamp and CDP. I hauled my rig to the annual Carverfest retreat in NC last year-- the Bobfather loved my speakers and put his signature on my Carver amps.

Cellphone video from Carverfest

8. Image:


At Carverfest 2016

 

[Jazzman53]

I just built my dream speakers and I'm updating my system post to show them:

My system is now fully dipole, with OB mid-bass woofers and Ripol subs. The panels are wide-dispersion, symmetrically segmented wire-stator electrostats, and the mid-bass woofers are Peerless SLS 12's on semi-H baffles formed by the triangular base. The front and rear grills are magnetically attached. The step-up transformers, bias supplies, and segmentation resistor networks are under plexiglass at the rear of the speakers.

A video of the new speaker:


Full write up of the speaker design and build pics on my website:
http://jazzman-esl-page.blogspot.com/
A few system pics:

 

[Jazzman53]

Update 4/27/22:
Since my previous post; I've replaced the Behringer DEQ2496 & DCX2496 with a DBX Driverack Venu 360 DSP/Crossover.

The DBX is the coolest piece of gear I own. With it; I can tweak crossover frequencies & slopes, driver time alignments, parametric & graphic EQ's, etc, all in real-time from my listening spot on the sofa, using the iPad control app. The Behringers were good units but the user interface and room correction EQ'ing are downright primitive compared to the DBX Venu 360.

I've also replaced my original DIY Ripole subs with a pair of my latest design Ripole subs, which are a bit slimmer and much prettier. The unique coloration of the oak is a natural oil stain tinted with powdered turmeric root.

Ripole bass seems to arise from nowhere and recede back to nowhere, with very little interaction with the room-- unobtrusive and very, very clean.

 

[Robert D]

I enjoy seeing your creations. Are there any subs today in production that have woofers facing inward like that? I've never seen that before. The box has a port in the middle? Reminds me a bit of bandpass sub design. Back in the late 80s I had a big band pass in my car stereo.

Really cool designs you have. Has anyone ever asked you to make them speakers?

 

[Jazzman53]

The German speaker designer Axel Ridtahler holds the patent on this type of subwoofer, which is essentially a folded baffle dipole. In fact; the name "Ripole" is short for a Ridtahler dipole. Here's a commercial version made by Modal Acoustik under license from Axel Ridtahler.

BTW; Ripoles are open on the back:

Many people have requested my ESL speakers and Ripoles and I have built several pairs for close friends. Three years ago I built 4 pairs of my ESLs for my audio friends at Carverfest.

Last year I built two additional pairs of the MkIII ESLs, just to use use up the materials I had lying round. I still have these and I will sell them to anyone willing to pick them up in Savannah, GA (shipping costs would be prohibitive). They come magnetic grills, my 30-day full refund satisfaction guarantee, plus a 5-year warrantee (identical to Martin Logan's warranty. I've decided not to build any more speakers after these are gone-- they weren't designed to be commercially viable (too much work to build them) and I'm getting too old for this.

Below is something you will never see anywhere else... the four pairs I built for my Caverfest friends, all lined up in my living room. It took me the best part of a year to complete them:

 

[JonFo]

Since my previous post; I've replaced the Behringer DEQ2496 & DCX2496 with a DBX Driverack Venu 360 DSP/Crossover.

The DBX is the coolest piece of gear I own. With it; I can tweak crossover frequencies & slopes, driver time alignments, parametric & graphic EQ's, etc, all in real-time from my listening spot on the sofa, using the iPad control app. The Behringers were good units but the user interface and room correction EQ'ing are downright primitive compared to the DBX Venu 360.

Congrats on the new DriveRack!!!!

It is indeed an amazing tool for the role of Speaker Processor duties.
One of the things I love is the ability to save a ton of presets and quickly switch between them.

Do try the 'autowarmth' feature, it is very helpful on recordings from the 60's and 70's. Good old DBX120 emulation right there.
I keep a preset with that enabled for when I play recordings that either still has the RIAA EQ from mastering, or where they intentionally cut the bass before mastering.

At one point Harman had an iPad app where one could 'build' remote control layouts, but that went dead years ago.

Here's the one I had that allowed toggling the AutoWarmth and quickly adjusting the level. Added a mute for demo purposes:

 

[BigGuy]

Masterful cabinet-making, Jazzman. Beautiful!

 

[Jazzman53]

Congrats on the new DriveRack!!!!

It is indeed an amazing tool for the role of Speaker Processor duties.
One of the things I love is the ability to save a ton of presets and quickly switch between them.

Do try the 'autowarmth' feature, it is very helpful on recordings from the 60's and 70's. Good old DBX120 emulation right there.
I keep a preset with that enabled for when I play recordings that either still has the RIAA EQ from mastering, or where they intentionally cut the bass before mastering.

At one point Harman had an iPad app where one could 'build' remote control layouts, but that went dead years ago.

Here's the one I had that allowed toggling the AutoWarmth and quickly adjusting the level. Added a mute for demo purposes:

View attachment 22678

The Venu 360 doesn't have an "AutoWarmth" but it does have an adjustable subharmonic synthesizer which, when enabled, enhances the low bass on those older albums recorded before digital media that couldn't hold a lot of bass energy. It makes a huge difference and sounds natural when applied with discretion.

 

[Robert D]

Masterful cabinet-making, Jazzman. Beautiful!

I wish I had the skill to do that. I dont even own the tools either. My neighbor is like that and builds a lot of stuff. I have just a few tools and learn stuff as I go along.

 

[JonFo]

The Venu 360 doesn't have an "AutoWarmth" but it does have an adjustable subharmonic synthesizer which, when enabled, enhances the low bass on those older albums recorded before digital media that couldn't hold a lot of bass energy. It makes a huge difference and sounds natural when applied with discretion.

Glad to hear you are enjoying the feature.

The 4800 has both features, so I'm sad to hear the 360 dropped the AutoWarmth, but not surprised. With AV processors offering features like DynamicEQ, the need for that in a non-integrated speaker processor is lower.

I will be replacing the existing Driveracks with either a Trinnov Altitude32 (so I can do everything in one box), or get four Venu360's. My 4800 is now 14 years old (May 2008), so getting ready to have a plan B in case it dies, but it seems bullet-proof.

 

[Jazzman53]

Since my last update I've replaced the RiPol subs yet again, with a third version which are even more compact (1/2" less height & depth). I also angled the wood grain directions for aesthetics.

A RiPol has a cardioid radiation pattern which tends to not excite the room's resonance, but it's really unique feature is that it forces the woofers' resonance (FS) downward, about 10Hz lower than it would be in free air-- and the smaller you make the chambers, the lower the resonance goes!

In this case; the woofer's resonance is reduced to below 20Hz, and since most music doesn't contain any energy down that low anyway, it's unlikely the woofers' resonance would ever be excited, or even occur, let alone heard.

The new subs are look and sound wonderful!

 

[Robert D]

Since my last update I've replaced the RiPol subs yet again, with a third version which are even more compact (1/2" less height & depth). I also angled the wood grain directions for aesthetics.

A RiPol has a cardioid radiation pattern which tends to not excite the room's resonance, but it's really unique feature is that it forces the woofers' resonance (FS) downward, about 10Hz lower than it would be in free air-- and the smaller you make the chambers, the lower the resonance goes!

In this case; the woofer's resonance is reduced to below 20Hz, and since most music doesn't contain any energy down that low anyway, it's unlikely the woofers' resonance would ever be excited, or even occur, let alone heard.

The new subs are look and sound wonderful!

View attachment 25593

How do the subs perform for home theater? Have you tried yet? Some frequencies may be lower in home theater audio?

 

[Jazzman53]

How do the subs perform for home theater? Have you tried yet? Some frequencies may be lower in home theater audio?

My system is left/right stereo and only used for music.

RiPol's may not be the best choice for home theater sound effects because, being dipoles, they are less efficient than conventional mono-poles and they don't pressurize the room with energy that hits you in the chest like a sledgehammer.

Perhaps supplimenting the Ripol's by adding a mono-pole sub could be a best-of-both-worlds solution for a home theater application? Something to think about...

The RiPol's can play profoundly low, with remakably fast, clear, and non-boomy bass. Just keep in mind that 85db efficiency and no room gain won't sound as loud in the room as a mono-pole sub, so a typical system would need more than one. I use and recommend a pair (4 x 12" woofers).

The Modal Akustik company in Germany sells a commercial RiPol sub which uses the same woofers that I use in mine. A review of the Modal Akustik sub by Six Moons Audio includes the following statement:

"For music-first listeners who prioritize speed, articulation and annunciated clarity, it's the long awaited messisah".

I feel the same way about my DIY RiPol's, and I won't ever go back to conventional box subs.