New ESL Project

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Jazzman53

Re: New ESL Project
« Reply #20 on: 13 Jun 2018, 11:48 pm »
These are indeed very nice looking.  At what frequency do you cut over the woofer?  Sorry if I missed this detail from earlier.

I had intended to cross the panel to the woofer around 220Hz but since I apparently over-tensioned the diaphragm (the 160Hz peak is the diaphragm's drum-head resonance)--so I had to raise the X-over frequency to 260Hz using  a 48db filter slope, so as to minimize exciting the resonance.  On the bottom end, the woofer crosses into the subs at 60Hz with a 24db filter slope.

Jazzman53

Re: New ESL Project
« Reply #21 on: 14 Jun 2018, 12:36 am »
Fantastique handy work Jazzman congratulations :thumb:
There is any way you can adjust the planar decay resonance time?

The diaphragm's drum-head resonance can be dampened to a degree by adding a cloth covering or felt pad strip (acoustic impedance) on the rear stator.  I'm not aware of any other technique to manipulate the resonance.  A rule of thumb for hybrid ESL's is to avoid exciting the resonance by setting the crossover frequency at least one octave above the resonance with a 48/octave filter, or 2 octaves above resonance with a 24db filter.     

PDR

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Re: New ESL Project
« Reply #22 on: 14 Jun 2018, 12:48 am »
Beautiful as always, thanks for sharing Charlie....... :thumb:

JakeJ

Re: New ESL Project
« Reply #23 on: 14 Jun 2018, 01:25 am »
You are a true craftsman, Jazzman.  Quite the amazing accomplishment.

<SNIP>
it will be a difficult decision (rather like selecting one of your children to sell). 

Sorry, I couldn't resist.
https://www.youtube.com/watch?v=AsWxkU0g9Z4

FullRangeMan

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Re: New ESL Project
« Reply #24 on: 14 Jun 2018, 01:35 am »
How much SPL it will have?

Jazzman53

Re: New ESL Project
« Reply #25 on: 14 Jun 2018, 11:54 am »
How much SPL it will have?

The ESL Calculator shows max SPL of 102 decibels at 3 meters (that's for the panel-- it doesn't calculate the woofer's output )

FullRangeMan

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Re: New ESL Project
« Reply #26 on: 14 Jun 2018, 12:27 pm »
This is amazing, my Carver Amazing have only 89dB, requiring a 300W monster amp.

Jazzman53

Re: New ESL Project
« Reply #27 on: 14 Jun 2018, 03:51 pm »
This is amazing, my Carver Amazing have only 89dB, requiring a 300W monster amp.

I've heard the Carver ribbons at Carverfest... the sound great but they do need a stout amp.  Most people cant believe how loud my speakers can play.  As a general rule, hybrid ESL's with close diaphragm to stator spacing (like mine) can play much louder than [let's say] a Quad 57 or 63.  And mine are very efficient (even for a hybrid) because the wire size and spacing yield high field density and optimum open area (42%).  I haven't measured the SPL myself but they can play to painful volume.  The 102 decibels I quoted was derived with Steve Bolser's ESL Calculator Excel spreadsheet (see screen shot below), which I used to determine the segmentation resistor values.  The green lines are panel frequency response and SPL with @ 1 watt input power at 3 meters.  The red line is max potential output at 3 meters.  Of course, the mechanical portions of the speaker won't produce sound out to 100kHz but the driving electrical output feeding the wire groups can extend that high.



« Last Edit: 14 Jun 2018, 05:42 pm by Jazzman53 »

FullRangeMan

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Re: New ESL Project
« Reply #28 on: 14 Jun 2018, 08:07 pm »
What is your membrane diafragm?
Any idea why the Amazing Kapton/alu Carver used sound so good?

Jazzman53

Re: New ESL Project
« Reply #29 on: 14 Jun 2018, 11:51 pm »
What is your membrane diafragm?
Any idea why the Amazing Kapton/alu Carver used sound so good?

The diaphragm is 6-micron (0.00025" thick) Mylar C, with 10.5" x 46.5" radiating area and weighing just under a gram (absent the coating).  The Licron Crystal conductive coating adds about 1.5 -2.0 microns and a bit more weight-- still lightening fast.

My friend Ed rebuilds those Carver ribbons at a reasonable price.  Unfortunately, Ed says the original 1 mil Kapton material is no longer available but he found a company willing to make up a batch of 2-mil Kapton with bonded aluminum conductors.  Ed made up a little hand powered rotary thingy that corrugates the film, like the originals.  It's a bit heavier ribbon than the originals but it sounds really good--- extends to about 15kHz, I think.   

 

FullRangeMan

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Re: New ESL Project
« Reply #30 on: 15 Jun 2018, 12:24 am »
The original 60'' respond to 40kHz according the factory specs.
The Amazing weak point was detail were not great by current standards, it needs a new ligther material.

There is a service manual here:
https://www.turntableneedles.com/Carver_Amazing_Dynamic_Loudspeaker_Instant_PDF_Download_English_Service_Manual

Tritium

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Re: New ESL Project
« Reply #31 on: 25 Jul 2018, 08:55 pm »
Nice job.

Excellent construction.

Thanks for posting this.

Jazzman53

Re: New ESL Project
« Reply #32 on: 16 Sep 2018, 01:31 am »
I figured it’s about time to update this thread:
As previously mentioned, this speaker was built for a friend who imposed a requirement that the speaker pair had to fit into his 2008 Audi for transport.   Hence; the OB bass section.

I had so many reservations about the design that I was hesitant to post anything more about it until I had confirmed that it works.  The low-qts woofer on an OB was a risky choice; giving priority to blending well with the ESL at the expense of requiring separate subs for the bottom two octaves—but my friend has DSP and awesome subs, so it’s not a problem. 

In the end the speakers turned out esthetically gorgeous, and thanks to some really smart people on the DIY Audio Forum who helped me along the way, they sound really nice too.  The video link below shows the speakers playing this past week at the 2018 Carverfest retreat in NC.  They made a big hit and the Bobfather (Bob Carver) raved about them. 

https://youtu.be/67Flmub-dYo