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Quad ESL 57

24.47.239.134

I have been enjoying a pair of ESL 57's for about a year now. These were made in 1963 and rebuilt by Electrostatic Solutions about 5-6 years ago.

Of late, I have been noticing a small buzz when playing low bass notes on recordings of small jazz ensembles. At first I thought it was the snare drum vibrating along with the bass as it does in some live performances, then I found it evident on even solo acoustic bass recording.

I should add that in most recordings, there is no audible buzz and the speakers are just marvelous.

I have damped the back screens with foam tape and added some weight to the back screen "shelf". This seems to have helped a bit, but the problem persists.

I have emailed Kent and am waiting for a response (hoping its not one of the bass panels going bad). The other thought I had was if maybe I should remove both the front and rear screens and run them naked. From what I have read this is the purist's way of listening to them.

They are driven by 25 watt EL34 mono blocks and never played loudly (at least as long as I have used them).

Any suggestions would be welcome.

Thanks!
Andy

Follow Ups:

RE: Quad ESL 57 - garyjac1 02:47:38 11/28/23 (1)
G'Day,

A small buzz at a low(er) frequency in any ESL can be caused by something as simple as a piece of sealing tape loosening up with time and age and vibration in response to the dust cover / diaphragm movement.

Play the relevant music just loud enough to hear this buzzing and move around the speaker to see if this noise is coming from a specific location. The more specific, the more likely it will be a detached piece of tape, or similar material in the speaker. If the "buzz" requires a high SPL to activate then it is more likely to be a small structural fault in the frame assembly. Things like screws do come loose, given time!

If the buzz is more general, then there is the possibility that a diaphragm issue is raising its ugly head, but let's hope that it's not that.

Regards,
Dr Gary Jacobson
- The Quad ESL (Open in New Window)
- RE: Quad ESL 57 - gja 03:36:12 11/28/23 (0)
  Thanks Gary.
  I'll give this a try and report back.
RE: Quad ESL 57 - kentaja 09:53:11 11/26/23 (3)
I don't recall receiving an email but I get a lot so I may have overlooked yours. Apologies if that is the case.

Please feel free to reach out to me through the Asylum email this will go to my personal email. I don't get as much traffic there.

While some people recommend removing the front/rear screens I don't recommend such things. Removing the rear screen will degrade the sound. Some claim this makes it better it doesn't. The rear screen, damping, tweeter felt is there to damp, reduce panel resonances. Removing the material creates a high Q, whompy kind of sound. Some may like that I don't. And objectively I can demonstrate how this moves the speaker in the wrong direction.

Removing the front safety screen will improves things a bit. A little better HF extension and bit more resolution. Yes I 'hear' the front screen but it doesn't screw up the sound. Removing it does expose the user to potentially lethal voltages. If you don't have kids, animals, drunk friends you are probably OK just don't go poking around when the amplifiers are on, playing.
- RE: Quad ESL 57 - hahax@verizon.net 19:39:03 11/26/23 (2)
  I heard a pair of ESL 57s without back damping. They sounded good. I mentioned that the designer wanted the damping there. The exhibiter answered that wasn't as much for control of sound as for problems interacting with small British listening rooms and the larger American rooms usually didn't have the problem.
  - RE: Quad ESL 57 - kentaja 05:26:33 11/27/23 (1)
    The Absolute Sound commissioned Keith Howard the editor of Hi-Fi Answers to interview Peter Walker in 1981. It appears in issue 23. The subject came up.
    
    KH: Some people have taken to removing the felt damping from the back of the speaker--what effect does that have?
    
    PW: Of course, it makes it more of a doublet, it has that advantage, but the treble unit will now resonate at 260 cycles with a very high Q which will show as a coloration. You might like it--it's about middle C on the piano. And the low frequencies will go woomp at the bottom end which many people like, but it's a high Q woomp. I don't think I would like it.
    
    I love PW's last comment. I get to hear it both ways almost daily and I most certainly don't care for them without the rear wave damping the speaker sounds just as PW describes. If one likes the sound this way certainly remove the damping it is after all their speaker their enjoyment.
    
    Objectively it is a step in the wrong direction just do a FR sweep and look at the differences in the panel resonances. This hobby certainly has people that fall in to the 'if I like it it's good' camp nothing wrong with that approach. PW was certainly not of that belief and neither am I.
    - RE: Quad ESL 57 - hahax@verizon.net 20:41:32 11/27/23 (0)
      I heard this modded ESL 57 a few years ago at the Capital Audio Show. Needless to say it wasn't a long audition but I definitely was impressed. I can't recall the modifier's name but I know he has experience working with Quad speakers over many years. And I suspect he did more than just remove the rear damping. It certainly called for more auditioning if it was a product being considered for purchase.

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