Jazzman's ESL/TL speakers

IslandPink · Post by **IslandPink** » Mon Sep 15, 2014 9:50 pm

Hi Charlie -
I've just started at :
http://jazzman-esl-page.blogspot.co.uk/ ... ables.html
- Can you tell us a little bit more about these speakers, especially ( for my purposes ) the TL section ?
I've just started to explore the pages, but you could point us to the best postings a bit more quickly.
Looks very interesting and original .

Mark

Jazzman53 · Post by **Jazzman53** » Mon Sep 15, 2014 11:11 pm

Scottmoose · Post by **Scottmoose** » Tue Sep 16, 2014 5:03 pm

Here's a simple to use Excel spreadsheet derived from Martin King's alignment tables:

http://www.quarter-wave.com/TLs/Alignme ... 3_3_09.xls

I strongly advise this is used over the above mentioned methodology, since it accounts for the driver's electromechanical characteristics, and thus its volume and tuning requirements. TLs are like any other vented enclosure in that the volume and tuning vary in accordance with the driver parameters. 0.5lbs ft^3 is the default packing density employed in the tables / the above spread sheet, assuming Dacron hollow-fibre material.

Heavily stuffing a line does not make it appear much longer -a little, but not much. Holdover from Bradbury, which was a lovely bit of maths, but sadly doesn't work too well. Usually, line CSA will want to be > 1.25*Sd, which, especially if the line is quite long & heavily damped, will tend to choke the output. Not necessarily a bad thing if you want a ~aperiodic line, but if the latter is wanted, a shorter, more heavily stuffed pipe is usually more practical. You may also wish to look at George Augspurger's work on the subject.

rowuk · Post by **rowuk** » Wed Sep 17, 2014 5:27 am

My best TL results were when I stuffed for flattest impedance around resonance.

I do admire the fine job here. Both the ESL and TL are beautiful and fit together well. I am pretty sure that the sound of the ESL will dictate how the line needs to be stuffed-otherwise the transition would be very audible.

Jazzman53 · Post by **Jazzman53** » Wed Sep 17, 2014 10:13 am

Scottmoose wrote:Here's a simple to use Excel spreadsheet derived from Martin King's alignment tables:

http://www.quarter-wave.com/TLs/Alignme ... 3_3_09.xls

I strongly advise this is used over the above mentioned methodology, since it accounts for the driver's electromechanical characteristics, and thus its volume and tuning requirements. TLs are like any other vented enclosure in that the volume and tuning vary in accordance with the driver parameters. 0.5lbs ft^3 is the default packing density employed in the tables / the above spread sheet, assuming Dacron hollow-fibre material.

Heavily stuffing a line does not make it appear much longer -a little, but not much. Holdover from Bradbury, which was a lovely bit of maths, but sadly doesn't work too well. Usually, line CSA will want to be > 1.25*Sd, which, especially if the line is quite long & heavily damped, will tend to choke the output. Not necessarily a bad thing if you want a ~aperiodic line, but if the latter is wanted, a shorter, more heavily stuffed pipe is usually more practical. You may also wish to look at George Augspurger's work on the subject.

Thank you Scottmoose for that easy TL calculator. It will come in handy if and when I design another speaker. I've not seen anything like your calculator before. When I designed my speaker in 2008 the data and multiple worksheets on MJK's website at that time seemed quite complicated and confusing to a math-dummy like myself. Fortunately, the bass from my speaker sounds really good anyway.

One odd thing I do in all of my speaker builds [before I install the woofer into the box] is to place my head near or in the box's woofer cutout and start humming up and down scale until I excite the box resonance, to determine how resonant the box is. All of the woofer box's I've built in the past, no matter how well dampened with stuffing, would resonate rather loudly and some would rattle my skull quite uncomfortably.

However, with this TL box (my first TL build), when I stuck my head in the woofer opening and hummed, I heard nothing at all-- graveyard dead it seemed. I deduced from this that the curvature of the line behind the woofer gave no parallel surfaces from which to bounce any sound back to my ears (or woofer cone). And perhaps the open-ended terminus helped as well. In any case, the sound from this TL is remakably less colored than any of the sealed or ported woofer box's I had previously built.

Thanks again, Charlie

Jazzman53 · Post by **Jazzman53** » Wed Sep 17, 2014 11:29 am

rowuk wrote:My best TL results were when I stuffed for flattest impedance around resonance.

I do admire the fine job here. Both the ESL and TL are beautiful and fit together well. I am pretty sure that the sound of the ESL will dictate how the line needs to be stuffed-otherwise the transition would be very audible.

Thanks Rowuk,
The woodwork was the hard part. The simple stat panels and power supplies I built from scratch over a long weekend but it took me over a month of evenings/weekends to complete the woodwork.

If people knew how easy the ESL components are to build, perhaps more DIY'ers would take the plunge into ESL's. And it's become my mission to facilitate that thru my website. As you can see from the attached photo, the electronics interface in my speaker is so simple that even an electronics dummy like me could do it.

And having now experienced bi-amping thru and active crossover, I will never use a passive crossover again. I really admire guys that know how to tweak passive crossovers to get good results but for me going active greatly simplified fine tuning the speaker.

By a huge margin, these speakers surpass anything I've built before. Their clarity and speed are astounding. And they sound even better since I added the Ripole subs, crossing in at 50Hz on a 48/db slope [now a tri-amp setup]. The Ripoles unloaded the TL woofers considerably and their cardroid radiation pattern doesn't excite room modes very clean.

The knock on hybrid ESL's is their typical poor blending between the woofer and ESL. But mine blend so seamlessly that the woofer and panel sound like a single driver"in the sweet spot, that is. I think the TL and high quality woofer made the difference here.

Anything said about a flat-panel ESL should include the caveat "in the sweet spot". These are the most directional speakers I've ever heard like two laser beams giving an intense sweet spot at the focal point. As such, they have great slam and spooky-real imaging (in the sweet spot). Moving out of the sweet spot the highs fall off a cliff and the sound goes from perfectly balanced to bass-heavy. But when you move far enough outside of the sweet spot that room reflections become dominant, the sound again becomes balanced.

My website is a labor of love. Now that I'm pushing retirement age with scary little savings, I can no longer afford to indulge this hobby of ours-- but at least I can live vicariously through others via my website. And it's hugely rewarding when someone on the other side of the planet is inspired to build their own ESL's and they write to me raving about how fantastic they sound" because I know what the effort and the results meant for them.

Scottmoose · Post by **Scottmoose** » Wed Sep 17, 2014 11:35 am

Very nice work indeed.

Not my calculator (sadly) -the spread sheet was written by Keith Webb, using the equations in Martin King's alignment tables. One of these days, I keep meaning to do something similar for Augspurger's, but his tables were far more abbreviated in comparison to Martin's, at least in terms of driver Q, Vas et al, so there would be somewhat more extrapolation involved.

Well, you would if you stuck your head into a vented box & hummed.

They're Helmholtz resonators. If it's a nominal sealed box, sticking your bonce through the driver cut-out & humming will still produce that same effect, since you haven't got any kind of air-seal between cut-out and your head / neck, so it's immediately become a vented enclosure / Helmholtz resonator, albeit inadvertently.

TLs are slightly different. The term has become such a catch-all that it is often used to describe boxes that are the functional opposites of each other. A 'pure' TL is a line stuffed or otherwise damped with the sole objective of providing the flattest possible impedance load. Zero other considerations. It will have in practical terms no audible output from the terminus. Very few (including Bailey's) are so extreme though, and they tend to be variations of resonant pipes, stuffed / damped to preserve some of the fundamental resonance (in this case eigenmodes rather than Helmholtz cavity resonance, which assumes a uniform air-particle density and no standing waves) while attenuating the unwanted harmonics. Since the alignment itself is usually well damped, and you've got a large amount of stuffing in there rapidly attenuating the shorter wavelengths, you tend to get a reasonably clean response with little ringing.

IslandPink · Post by **IslandPink** » Wed Sep 17, 2014 6:46 pm

Thanks for the spreadsheet , Scott. Have been running off a few examples today in gaps between work

Charlie - been reading the blog a bit more - great work there , such a lot of detail goes into those ESLs, you must have put in some hours there !
The TL bass solution is inspired . It may just give me the neatest solution to my combo if I decide to go TL for the lower octaves. I have been mulling over how a TL bass unit could be shaped underneath OB mids , without putting the OB/horn too high, or filling up floor space with a big box you could trip over ( into the exposed 500V power supply ).
To consider putting the TL line directly behind, but have the 'V' front to deflect the back wave, is a really original idea .

Jazzman53 · Post by **Jazzman53** » Wed Sep 17, 2014 9:01 pm

IslandPink wrote: The TL bass solution is inspired ....To consider putting the TL line directly behind, but have the 'V' front to deflect the back wave, is a really original idea .

Yeah, I was really proud of myself for dreaming that up-- until about six months ago when I came across the sketch below. It was quite deflating to learn that Shackman had done exactly the same thing 25 years ago. Oh well-- I suppose I should not be surprised that someone else came up with the same solution to the same problem, as I can't imagine another way of doing it.

Scottmoose · Post by **Scottmoose** » Wed Sep 17, 2014 10:27 pm

As Tom Danley has been known to complain, 'the ancients keep stealing all my best ideas.'

Greg · Post by **Greg** » Wed Sep 17, 2014 11:03 pm

Jazzman, if you could reduce the size of your photo's, it would make this interesting thread much more readable.

Jazzman53 · Post by **Jazzman53** » Wed Sep 17, 2014 11:13 pm

Greg wrote:Jazzman, if you could reduce the size of your photo's, it would make this interesting thread much more readable.

I agree... I just don't know how to do it.... OK, how about now?

Greg · Post by **Greg** » Thu Sep 18, 2014 9:51 am

Excellent! Thank you

Jazzman53 · Post by **Jazzman53** » Thu Sep 18, 2014 9:59 am

Greg wrote:Excellent! Thank you

BTW, forgot to mention: These speakers blow women's panties right off.
My GF says that could happen anyway but I'm just saying...

steve s · Post by **steve s** » Thu Sep 18, 2014 10:27 am

Jazzman53 wrote:
Greg wrote:Excellent! Thank you
BTW, forgot to mention: These speakers blow women's panties right off.
My GF says that could happen anyway but I'm just saying...

So you have to be careful what you wear then...
Interesting speakers i would say, And a whole new level of ingenuity

Scott thats a challenge for your next design

audio-talk

Jazzman's ESL/TL speakers

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