I wonder if anyone knows how Electrostatic loudspeakers can have any sort of 
bass response.

An ESL is a doublet that radiates equally front and back. With a normal cone 
loudspeaker on a finite baffle, the bass starts to roll off at a frequency 
whose quarter-wavelength corresponds to the smallest dimension of the 
baffle. Looking at the dimensions of, for example, the ESL63, the bass 
should start rolling off below about 320Hz, but in fact is maintained down 
to a -6dB point of 34Hz.

How is this possible? Is there some extreme EQ built-in to the ESL63 which I 
am unaware of, or does the physics work in a different way for a panel 
driven over its entire width or what?

Similarly, other electrostatics have small dimensions, yet can go fairly 
deep in the bass, even those ultimately assisted by cone woofers.

I have Roger Sander's Electrostatic Cookbook, but he doesn't make clear how 
ESL's bass response is maintained, except to use an external woofer or 
savage EQ. His graphs for the response of an ESL panel shows the output 
dropping from mid-frequencies, then a resonance rise at quite low 
frequencies. It doesn't explain how to fill in the upper-bass/lower mid hole 
except with extreme EQ. In the QUAD ELSs, I wasn't aware of any EQ.


Thanks

S.
-- 
http://audiopages.googlepages.com

"Serge Auckland
>
>I wonder if anyone knows how Electrostatic loudspeakers can have any sort 
>of bass response.
>
> An ESL is a doublet that radiates equally front and back. With a normal 
> cone loudspeaker on a finite baffle, the bass starts to roll off at a 
> frequency whose quarter-wavelength corresponds to the smallest dimension 
> of the baffle. Looking at the dimensions of, for example, the ESL63, the 
> bass should start rolling off below about 320Hz,

** Huh  ???????????????

The width of an ESL 63 is circa 1 metre.

A wave of 4 metres has a frequency of 80 Hz.


> but in fact is maintained down  to a -6dB point of 34Hz.


**  It really does too.

Cos it is taller than 1 metre and there is little back to front sound 
transfer  -   a huge SPL null exists all round at 90 degrees to the central 
axis.


> How is this possible?

** You cannot do math -  or much else,  can you.

BTW:

There are many examples of modest sized speakers which radiate back and 
front and yet have quite good bass output.

Ever seen a combo guitar amplifier  ????

Most have open back cabinets with 2 or maybe 4 x 12inch speakers fitted 
neatly inside  -   so are less than 1 metre square. Output is well 
maintained to at least 80 Hz and is still strong at 60 Hz. Been testing them 
with sine generators most of my life.

Also,  the famous Wharfedale SFB-3 open back 3-way speaker of 1956:

http://www.troelsgravesen.dk/Wharfedale_cat_files/SFB-3.pdf

Pre-dates the Quad ESL57.

Response down to 35 Hz is claimed.

Magic ??



.....    Phil

Phil Allison wrote:
> "Serge Auckland
> 
>>I wonder if anyone knows how Electrostatic loudspeakers can have any sort 
>>of bass response.
>>
>>An ESL is a doublet that radiates equally front and back. With a normal 
>>cone loudspeaker on a finite baffle, the bass starts to roll off at a 
>>frequency whose quarter-wavelength corresponds to the smallest dimension 
>>of the baffle. Looking at the dimensions of, for example, the ESL63, the 
>>bass should start rolling off below about 320Hz,
> 
> 
> ** Huh  ???????????????
> 
> The width of an ESL 63 is circa 1 metre.
> 
> A wave of 4 metres has a frequency of 80 Hz.
> 
> 
> 
>>but in fact is maintained down  to a -6dB point of 34Hz.
> 
> 
> 
> **  It really does too.
> 
> Cos it is taller than 1 metre and there is little back to front sound 
> transfer  -   a huge SPL null exists all round at 90 degrees to the central 
> axis.
> 
> 
> 
>>How is this possible?
> 
> 
> ** You cannot do math -  or much else,  can you.
> 
> BTW:
> 
> There are many examples of modest sized speakers which radiate back and 
> front and yet have quite good bass output.
> 
> Ever seen a combo guitar amplifier  ????
> 
> Most have open back cabinets with 2 or maybe 4 x 12inch speakers fitted 
> neatly inside  -   so are less than 1 metre square. Output is well 
> maintained to at least 80 Hz and is still strong at 60 Hz. Been testing them 
> with sine generators most of my life.
> 
> Also,  the famous Wharfedale SFB-3 open back 3-way speaker of 1956:
> 
> http://www.troelsgravesen.dk/Wharfedale_cat_files/SFB-3.pdf
> 
> Pre-dates the Quad ESL57.
> 
> Response down to 35 Hz is claimed.
> 
> Magic ??
> 
> 
> 
Yep, look out for the books Gilbert Briggs wrote about loudspeaker 
design. Also in the case of the SFB-3 (and for that matter my own open 
baffle speakers) the tapered side panels also increase the front/back 
length.

-- 
Nick

"Nick Gorham"  wrote in message 
news:0072b94f$0$4746$c3e8da3@news.astraweb.com...
> Phil Allison wrote:
>> "Serge Auckland
>>
>>>I wonder if anyone knows how Electrostatic loudspeakers can have any sort 
>>>of bass response.
>>>
>>>An ESL is a doublet that radiates equally front and back. With a normal 
>>>cone loudspeaker on a finite baffle, the bass starts to roll off at a 
>>>frequency whose quarter-wavelength corresponds to the smallest dimension 
>>>of the baffle. Looking at the dimensions of, for example, the ESL63, the 
>>>bass should start rolling off below about 320Hz,
>>
>>
>> ** Huh  ???????????????
>>
>> The width of an ESL 63 is circa 1 metre.
>>
>> A wave of 4 metres has a frequency of 80 Hz.
>>
>>
>>
>>>but in fact is maintained down  to a -6dB point of 34Hz.
>>
>>
>>
>> **  It really does too.
>>
>> Cos it is taller than 1 metre and there is little back to front sound 
>> transfer  -   a huge SPL null exists all round at 90 degrees to the 
>> central axis.
>>
>>
>>
>>>How is this possible?
>>
>>
>> ** You cannot do math -  or much else,  can you.
>>
>> BTW:
>>
>> There are many examples of modest sized speakers which radiate back and 
>> front and yet have quite good bass output.
>>
>> Ever seen a combo guitar amplifier  ????
>>
>> Most have open back cabinets with 2 or maybe 4 x 12inch speakers fitted 
>> neatly inside  -   so are less than 1 metre square. Output is well 
>> maintained to at least 80 Hz and is still strong at 60 Hz. Been testing 
>> them with sine generators most of my life.
>>
>> Also,  the famous Wharfedale SFB-3 open back 3-way speaker of 1956:
>>
>> http://www.troelsgravesen.dk/Wharfedale_cat_files/SFB-3.pdf
>>
>> Pre-dates the Quad ESL57.
>>
>> Response down to 35 Hz is claimed.
>>
>> Magic ??
>>
>>
>>
> Yep, look out for the books Gilbert Briggs wrote about loudspeaker design. 
> Also in the case of the SFB-3 (and for that matter my own open baffle 
> speakers) the tapered side panels also increase the front/back length.
>
> -- 
> Nick

The width of the ELS63 is 66cm, a wavelength of 2.64 metres has a frequency 
of 130Hz (I mistakenly multiplied by 2, not 4 in my original post, my 
apologies.) So, I would expect the ELS63 to have a reducing bass output 
below 130 Hz. Why doesn't it? What about other ELS loudspeakers, like the 
Dutch Audiostatic that were about 30cm wide, and yet had a decent bass 
response. What about the Magneplanar MG3, which were not electrostatic, but 
nevertheless doublets, and had excellent bass response.

What am I missing?

S.


-- 
http://audiopages.googlepages.com

"Serge Auckland"
> "Nick Gorham"
>> Phil Allison wrote:
>>>
>>>>I wonder if anyone knows how Electrostatic loudspeakers can have any 
>>>>sort of bass response.
>>>>
>>>>An ESL is a doublet that radiates equally front and back. With a normal 
>>>>cone loudspeaker on a finite baffle, the bass starts to roll off at a 
>>>>frequency whose quarter-wavelength corresponds to the smallest dimension 
>>>>of the baffle. Looking at the dimensions of, for example, the ESL63, the 
>>>>bass should start rolling off below about 320Hz,
>>>
>>>
>>> ** Huh  ???????????????
>>>
>>> The width of an ESL 63 is circa 1 metre.
>>>
>>> A wave of 4 metres has a frequency of 80 Hz.
>>>
>>>
>>>>but in fact is maintained down  to a -6dB point of 34Hz.
>>>
>>>
>>> **  It really does too.
>>>
>>> Cos it is taller than 1 metre and there is little back to front sound 
>>> transfer  -   a huge SPL null exists all round at 90 degrees to the 
>>> central axis.
>>>
>>>
>>>
>>>>How is this possible?
>>>
>>>
>>> ** You cannot do math -  or much else,  can you.
>>>
>>> BTW:
>>>
>>> There are many examples of modest sized speakers which radiate back and 
>>> front and yet have quite good bass output.
>>>
>>> Ever seen a combo guitar amplifier  ????
>>>
>>> Most have open back cabinets with 2 or maybe 4 x 12inch speakers fitted 
>>> neatly inside  -   so are less than 1 metre square. Output is well 
>>> maintained to at least 80 Hz and is still strong at 60 Hz. Been testing 
>>> them with sine generators most of my life.
>>>
>>> Also,  the famous Wharfedale SFB-3 open back 3-way speaker of 1956:
>>>
>>> http://www.troelsgravesen.dk/Wharfedale_cat_files/SFB-3.pdf
>>>
>>> Pre-dates the Quad ESL57.
>>>
>>> Response down to 35 Hz is claimed.
>>>
>>> Magic ??
>>>
>>>
>>>
>> Yep, look out for the books Gilbert Briggs wrote about loudspeaker 
>> design. Also in the case of the SFB-3 (and for that matter my own open 
>> baffle speakers) the tapered side panels also increase the front/back 
>> length.
>>
>> -- 
>> Nick
>
> The width of the ELS63 is 66cm, a wavelength of 2.64 metres has a 
> frequency of 130Hz (I mistakenly multiplied by 2, not 4 in my original 
> post, my apologies.)

** This is simply not true either.


> So, I would expect the ELS63 to have a reducing bass output below 130 Hz. 
> Why doesn't it?


** Your original assertion is 100%  WRONG.

Go look up the *actual LF behaviour* of speakers mounted on flat rectangular 
baffles.

Allow that a baffle COVERED in similar bass speakers has deeper LF response 
than when only one is sited in the middle.

You really are a clueless turd.



.....    Phil

In article ,
   Serge Auckland  wrote:
> The width of the ELS63 is 66cm, a wavelength of 2.64 metres has a
> frequency of 130Hz (I mistakenly multiplied by 2, not 4 in my original
> post, my apologies.) So, I would expect the ELS63 to have a reducing
> bass output below 130 Hz. Why doesn't it?

Aren't they figure of eight DP - so no output on one axis?

-- 
*The most common name in the world is Mohammed *

    Dave Plowman        dave@davenoise.co.uk           London SW
                  To e-mail, change noise into sound.

In article , Serge Auckland
 wrote:


> The width of the ELS63 is 66cm, a wavelength of 2.64 metres has a
> frequency of 130Hz (I mistakenly multiplied by 2, not 4 in my original
> post, my apologies.) So, I would expect the ELS63 to have a reducing
> bass output below 130 Hz. Why doesn't it? 

> What am I missing?

Note that the 'piston mass' for an ESL is tiny compared with a dynamic
speaker unit. This means that when you apply a drive voltage to the plates
of an ESL you generate a pressure differential between  the front and back
surfaces of the diaphragm. At LF some air can easily whoosh around from
front to back. But this simply allows the diaphragm to move more quickly in
response to the applied E-field, and so maintains the same pressure
difference between front and back.

The effect is to allow the speaker to maintain the ability to generate the
same sound pressures for a given applied field as you lower the frequency.
This can't be perfect, of course, as away from the local soundfield region
you will get cancellation effects. But what you may be missing is that the
relationship between the air (radiation) and mass impedances for the ESL
are unlike those for the conventional dynamic unit.

The real problem is that the diaphragm excursions become too large if you
want high sound pressures at LF

Slainte,

Jim

-- 
Change 'noise' to 'jcgl' if you wish to email me.
Electronics  http://www.st-and.ac.uk/~www_pa/Scots_Guide/intro/electron.htm
Armstrong Audio  http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc  http://www.audiomisc.co.uk/index.html

Serge Auckland wrote:
> 
> "Nick Gorham"  wrote in message 
> news:0072b94f$0$4746$c3e8da3@news.astraweb.com...
> 
>> Phil Allison wrote:
>>
>>> "Serge Auckland
>>>
>>>> I wonder if anyone knows how Electrostatic loudspeakers can have any 
>>>> sort of bass response.
>>>>
>>>> An ESL is a doublet that radiates equally front and back. With a 
>>>> normal cone loudspeaker on a finite baffle, the bass starts to roll 
>>>> off at a frequency whose quarter-wavelength corresponds to the 
>>>> smallest dimension of the baffle. Looking at the dimensions of, for 
>>>> example, the ESL63, the bass should start rolling off below about 
>>>> 320Hz,
>>>
>>>
>>>
>>> ** Huh  ???????????????
>>>
>>> The width of an ESL 63 is circa 1 metre.
>>>
>>> A wave of 4 metres has a frequency of 80 Hz.
>>>
>>>
>>>
>>>> but in fact is maintained down  to a -6dB point of 34Hz.
>>>
>>>
>>>
>>>
>>> **  It really does too.
>>>
>>> Cos it is taller than 1 metre and there is little back to front sound 
>>> transfer  -   a huge SPL null exists all round at 90 degrees to the 
>>> central axis.
>>>
>>>
>>>
>>>> How is this possible?
>>>
>>>
>>>
>>> ** You cannot do math -  or much else,  can you.
>>>
>>> BTW:
>>>
>>> There are many examples of modest sized speakers which radiate back 
>>> and front and yet have quite good bass output.
>>>
>>> Ever seen a combo guitar amplifier  ????
>>>
>>> Most have open back cabinets with 2 or maybe 4 x 12inch speakers 
>>> fitted neatly inside  -   so are less than 1 metre square. Output is 
>>> well maintained to at least 80 Hz and is still strong at 60 Hz. Been 
>>> testing them with sine generators most of my life.
>>>
>>> Also,  the famous Wharfedale SFB-3 open back 3-way speaker of 1956:
>>>
>>> http://www.troelsgravesen.dk/Wharfedale_cat_files/SFB-3.pdf
>>>
>>> Pre-dates the Quad ESL57.
>>>
>>> Response down to 35 Hz is claimed.
>>>
>>> Magic ??
>>>
>>>
>>>
>> Yep, look out for the books Gilbert Briggs wrote about loudspeaker 
>> design. Also in the case of the SFB-3 (and for that matter my own open 
>> baffle speakers) the tapered side panels also increase the front/back 
>> length.
>>
>> -- 
>> Nick
> 
> 
> The width of the ELS63 is 66cm, a wavelength of 2.64 metres has a 
> frequency of 130Hz (I mistakenly multiplied by 2, not 4 in my original 
> post, my apologies.) So, I would expect the ELS63 to have a reducing 
> bass output below 130 Hz. Why doesn't it? What about other ELS 
> loudspeakers, like the Dutch Audiostatic that were about 30cm wide, and 
> yet had a decent bass response. What about the Magneplanar MG3, which 
> were not electrostatic, but nevertheless doublets, and had excellent 
> bass response.
> 
> What am I missing?
> 
> S.
> 
> 

I think yopu have to take both path lengths into account. Also you need 
to consider that as the baffle bass response drops off, thats when the 
room gain starts to kick in.

As it happens, Septembres HiFi world has a article on the SFB-3 with 
some measurements. They find that the bass starts to roll off at about 
100-120hz if you discount the effect of the room.

If you can't find a copy let me know and I will try and scan it in.

My OBs use a 15% base unit, the front panel is aprox 20" * 48" with 
tapering sides that are 24" deep at the base up to zero at the top. They 
measure flat (ish) down to about 40hz in room, when the bass starts to 
fall away at about 6dB/Octave

-- 
Nick

Nick Gorham wrote:

> I think yopu have to take both path lengths into account. Also you need 
> to consider that as the baffle bass response drops off, thats when the 
> room gain starts to kick in.


Does room gain work with an ESL?

-- 
Eiron.

Eiron wrote:

> Nick Gorham wrote:
> 
>> I think yopu have to take both path lengths into account. Also you 
>> need to consider that as the baffle bass response drops off, thats 
>> when the room gain starts to kick in.
> 
> 
> 
> Does room gain work with an ESL?
> 

AFAIK, though it excites a null.

BTW, I am not claming to know that much about this stuff, I have some 
speakers I am happy with, though they are effectivly cardioid in their 
bass response due to the side panels, but that was intentional as they 
have to live in my small listening room.

-- 
Nick

"Serge Auckland"  wrote in
message news:AIednVS21MNlPDPVnZ2dnUVZ8j2dnZ2d@bt.com

> I wonder if anyone knows how Electrostatic loudspeakers
> can have any sort of bass response.

The most severe problem would probably not be the E/S design, it would be 
the common use of open backs.

The back sides of loudspeakers are commonly enclosed to prevent the wave 
created by the back side of the driver from radiating around to the front, 
and cancelling the wave created by the front side of the speaker. Since low 
frequencies aren't very directional, there's a very good chance of this 
happening.

I don't know about the basic bass resonances of common E/S drivers, but the 
smaller ones are likely to have fairly high bass resonances, which also 
restricts their bass response.

Building a large E/S driver with a low bass resonance, supporting acoustic 
response down to say 20-40 Hz, shouldn't be a problem.

Finally, the bass response of the matching transformer needs to be 
considered.