Stacked pair of Quad ESL 57 - Page 4

a.wayne · 13th April 2012, 11:28 PM

Quote:

Originally Posted by AVWERK

Ra
Actually there are a number of speaker manf. that do follow the same principals to get step response that comes real close to the Quads, Thiel, Vandersteen, and just about anyone that follows the 6db rule of crossover design and arrival time.

What I didn't expect from the 2805 was the rolled off top end in that review, the best examples of the 57 went further out

Regards
David

Consider how it's being measured , reflections will do that . I wish JA would be more consistent in his measuring technique, well considering the polemics involved , maybe not ..

arend-jan · 14th April 2012, 08:58 PM

How was it measured? Can't find the review online...

It's notoriously hard to measure large panel transducers without a reflection free chamber. Near field measurements don't tell the whole story and indoor far field measurements are polluted with reflections.

stokessd · 14th April 2012, 11:36 PM

I don't know about stereophile in a long time, but they used to have real problems with microphone positioning. The original innersound speakers used to have seriously beamy panels, and it was obvious in the measurements that they were not really on axis.

My measurements of both the 57's and 63's show that the 63's are significantly more extended.

Using a quasi-enchoic response technique (with MLS pulses), you can remove the room effects and get very clean response above a few hundred hertz.

A big flat panel can be insanely beamy, here's a 20" x 48" panel measured over 5 degrees of polar response:

http://www.quadesl.com/speaker/diyesl/polar_fine.gif

Sheldon

arend-jan · 15th April 2012, 01:24 PM

That is one nasty beaming panel

Looks like the graph has been smoothed, perhaps 1/6 octave?

Yes you can window out the reflections which gives you enough data to show something above a couple of hundred Herz. But at a large distance the window becomes smaller and smaller which results in rather poor frequency resolution.

Even a modest size ESL like the Quad 57 needs a mic distance of at least 2m for the different segments to integrate properly. Preferably even 4m as stated by Quad. At 1 meter microphone and speaker height, this gives a best case time window of 1.4ms max. Which gives a frequency resolution of 700Hz and all you get are wiggling smoothed curves that don't reveal much detail.

Hence the dilemma. Near field measurements are not representative for large panel transducers, far field measurements require a small time window with poor frequency resolution.

Something else, you mention that you get more extended high frequencies than published. This could of course be the case, but I wonder if your microphone is calibrated? The often used Behringer ECM8000 for example has a large and broad response peak between 10-20 kHz... just something that came to mind.

a.wayne · 15th April 2012, 01:51 PM

A PK refurbed ESL57 got featured on Stereophile's website yesterday, they were covering their NY show, best sound was mentioned ....

arend-jan · 15th April 2012, 01:59 PM

Quote:

Originally Posted by a.wayne

A PK refurbed ESL57 got featured on Stereophile's website yesterday, they were covering their NY show, best sound was mentioned ....

Nice, yes it should not be possible but those 50+ year old ESLs can still hold up their own against a lot of speakers. When in proper condition of course. Adding a $20.000 OTL tube amp does not hurt either

Thanks for the pointer!

AVWERK · 15th April 2012, 03:19 PM

Nothing really today at any level or cost will beat the 57 fo that midrange detail and microdynamics

Regards
David

stokessd · 16th April 2012, 09:25 PM

Quote:

Originally Posted by arend-jan

Something else, you mention that you get more extended high frequencies than published. This could of course be the case, but I wonder if your microphone is calibrated? The often used Behringer ECM8000 for example has a large and broad response peak between 10-20 kHz... just something that came to mind.

I guess I wasn't clear, I get more extended response I referred to was that the 63's have more extended response than the 57's in response to AVWERK's comment earlier in the thread.

I have a calibrated Behringer mic, as well as a panasonic electret, and for serious work, a B&K 1/2" lab mic.

Sheldon

woodturner-fran · 16th April 2012, 09:54 PM

Sheldon/Arend-jan - a slightly OT question for you both:

Which is the harder to rebuild panels on - the 63 or 57 - assuming say I'm using a kit from ER?

Fran

stokessd · 17th April 2012, 12:17 AM

I find the 57's to be a little more tricky, often due to treble panel warping or deformation over years of storage. The 57 panels are not built with the same precision as the 63's. So getting matched response from panels is harder. Plus many 57 treble panels have burned areas that need repaired. And they all are older with more potential for neglect and issues. There is a ton of rivets to remove for each 57 panel, and replace with some other rivet-like fastener (I use nuts and bolts).

The 63 frames and stators are higher precision. The glue that holds the circuit board stators to the frames is the Achilles heal of the 63's and the crappy quad glue has paid for many vacations for me. There are two more panels on the 63's, but they are a lot easier to rebuild. The 63's are held together better, not relying on tape, plywood frames, and visible expanded metal grilles. Taking apart and reassembling a 63 is easier, but is tedious due to the many connections to the panels, but the connections are pretty obvious.

The electronics in the 63's is more complex. There is a clamp circuit that is fairly involved. The high voltage supply is a bit more complex. The delay lines are also more complex but are essentially trouble free in my experience.

In terms of ER kits, I think the 63 kit is more complete and overall easier to follow and produces a result that is very close to the original Quad speaker when complete. The ER 57 kit is a little bit of a departure from the way I rebuild the 57's, and the manual (as I've seen it a year or so ago) is a little less complete than the 63 manual.

It's really a matter of personal taste (57 vs 63) and what you can find to buy and rebuild. I've had a lot of both types over the 15+ years I've been rebuilding and using them. The 57's have a midrange transparency that is hard to beat, arguably the best out there in the sweet spot. The 57's don't have as good of extension in the bass and treble. The 63's have better dispersion, you can get very good tonal balance farther away from the sweet spot than with the 57's. The 63's look much much nicer than the 57's (IMHO), with the 57's looking like they were built in a garage.

Sheldon

15th April 2012, 01:24 PM	#34
arend-jan diyAudio Member Join Date: May 2006 Location: Netherlands	That is one nasty beaming panel Looks like the graph has been smoothed, perhaps 1/6 octave? Yes you can window out the reflections which gives you enough data to show something above a couple of hundred Herz. But at a large distance the window becomes smaller and smaller which results in rather poor frequency resolution. Even a modest size ESL like the Quad 57 needs a mic distance of at least 2m for the different segments to integrate properly. Preferably even 4m as stated by Quad. At 1 meter microphone and speaker height, this gives a best case time window of 1.4ms max. Which gives a frequency resolution of 700Hz and all you get are wiggling smoothed curves that don't reveal much detail. Hence the dilemma. Near field measurements are not representative for large panel transducers, far field measurements require a small time window with poor frequency resolution. Something else, you mention that you get more extended high frequencies than published. This could of course be the case, but I wonder if your microphone is calibrated? The often used Behringer ECM8000 for example has a large and broad response peak between 10-20 kHz... just something that came to mind. __________________ my Quad ESL website.

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14th April 2012, 08:58 PM	#32
arend-jan diyAudio Member Join Date: May 2006 Location: Netherlands	How was it measured? Can't find the review online... It's notoriously hard to measure large panel transducers without a reflection free chamber. Near field measurements don't tell the whole story and indoor far field measurements are polluted with reflections.

14th April 2012, 11:36 PM	#33
stokessd diyAudio Member Join Date: Nov 2002 Location: Fort Wayne, IN	I don't know about stereophile in a long time, but they used to have real problems with microphone positioning. The original innersound speakers used to have seriously beamy panels, and it was obvious in the measurements that they were not really on axis. My measurements of both the 57's and 63's show that the 63's are significantly more extended. Using a quasi-enchoic response technique (with MLS pulses), you can remove the room effects and get very clean response above a few hundred hertz. A big flat panel can be insanely beamy, here's a 20" x 48" panel measured over 5 degrees of polar response: http://www.quadesl.com/speaker/diyesl/polar_fine.gif Sheldon

15th April 2012, 01:51 PM	#35
a.wayne diyAudio Member Join Date: May 2008 Location: Front Row Center	A PK refurbed ESL57 got featured on Stereophile's website yesterday, they were covering their NY show, best sound was mentioned ....

15th April 2012, 03:19 PM	#37
AVWERK diyAudio Member Join Date: Jan 2004 Location: OC,Calif.	Nothing really today at any level or cost will beat the 57 fo that midrange detail and microdynamics Regards David

16th April 2012, 09:54 PM	#39
woodturner-fran diyAudio Member Join Date: Jan 2006 Location: Ireland	Sheldon/Arend-jan - a slightly OT question for you both: Which is the harder to rebuild panels on - the 63 or 57 - assuming say I'm using a kit from ER? Fran

17th April 2012, 12:17 AM	#40
stokessd diyAudio Member Join Date: Nov 2002 Location: Fort Wayne, IN	I find the 57's to be a little more tricky, often due to treble panel warping or deformation over years of storage. The 57 panels are not built with the same precision as the 63's. So getting matched response from panels is harder. Plus many 57 treble panels have burned areas that need repaired. And they all are older with more potential for neglect and issues. There is a ton of rivets to remove for each 57 panel, and replace with some other rivet-like fastener (I use nuts and bolts). The 63 frames and stators are higher precision. The glue that holds the circuit board stators to the frames is the Achilles heal of the 63's and the crappy quad glue has paid for many vacations for me. There are two more panels on the 63's, but they are a lot easier to rebuild. The 63's are held together better, not relying on tape, plywood frames, and visible expanded metal grilles. Taking apart and reassembling a 63 is easier, but is tedious due to the many connections to the panels, but the connections are pretty obvious. The electronics in the 63's is more complex. There is a clamp circuit that is fairly involved. The high voltage supply is a bit more complex. The delay lines are also more complex but are essentially trouble free in my experience. In terms of ER kits, I think the 63 kit is more complete and overall easier to follow and produces a result that is very close to the original Quad speaker when complete. The ER 57 kit is a little bit of a departure from the way I rebuild the 57's, and the manual (as I've seen it a year or so ago) is a little less complete than the 63 manual. It's really a matter of personal taste (57 vs 63) and what you can find to buy and rebuild. I've had a lot of both types over the 15+ years I've been rebuilding and using them. The 57's have a midrange transparency that is hard to beat, arguably the best out there in the sweet spot. The 57's don't have as good of extension in the bass and treble. The 63's have better dispersion, you can get very good tonal balance farther away from the sweet spot than with the 57's. The 63's look much much nicer than the 57's (IMHO), with the 57's looking like they were built in a garage. Sheldon