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