ER Audio Electrostatics - QUAD ESL beaters.

[JiriAU]

Dear Sir,

I have just recently found this forum and I was pleased as I’m very interested at ER Audio Acorn speaker kit. At first I would like to mention my setup. I have been using active setup, which I find it better that passive.

I do use 2 Subs Whise Acoustic profunders pro. 624 pasive.I was never subs person however this subs change my approach towards them. I have 3 way digital crossover from DEQX http://www.deqx.com/ which I’m able to:

Magnitude/Frequency response calibration

Phase/Frequency response calibration

Time alignment

Active 3 way digital crossover

Parametric EQ

Room measuring /calibration

Speaker’s measuring/calibration

And more …………

I do use a different amps (6 channels) for 2 active channel audio mostly Digital like NUFORCE SE, H2O, BEL CANTO, and also some solid state like Bryston, Crown

I have used a lot of different speakers mostly cone box type expensive and inexpensive also DIY speakers which I found to be the best but still not there in terms of sound quality. I have to mention the most important that ELS panels from Martin Logan – Odyssey was the best passive setup I have ever had some time ego. Nevertheless I would like to keep active as the potentials are boundless and also after long setup it is worth the effort and the results are really great. However I want to try it with ESL panels particualy with ER audio Acorn model.

I have contact Rob last year from ER audio and make some enquiries he send me his recommendation on how to apply his acorn with active setup but unfortunately I have lost all the info due to moving also my PC lost all files. I ‘m trying now to get contact with Rob but he is provable away .I also find this forum and thought to ask you few question as it seems you know the most having both models at home if you could help me out or have some recommendation it would be great.

With the ESL Panels Acorns they have 3 separated sizes obviously the bigger one is for bass and middle one for mid and the smallest one for high frequencies. Basically what I’m after is 2 ways which I have to make from Acorn to make my setup work as I mentioned I would like to use my subs. So I thought

1) The smaller section with the middle section run as one and let say to run it from 300 Hz, or 400 Hz or 500 Hz to 20000 Hz.

2) The bass section from 80hz to 300 Hz 400hz,500 Hz

3) Use than my sub from 80hz to 20hz

I think that I mention that to Rob but (not sure!) he had a different opinion and I think it was

1) The smaller section use by itself just for the high’s I have no idea where that crossover point would be

2) Use the middle section and also the bass section as one go to 80hz

3) Than use my subs from 80hz down

I have to mention that I’m aware of extra power and audio transformers and so on. If you have any suggestion please let me know even when differ from all this above I would really appreciated as I hope to finish all in the near future.

Thank you

Jiri

[vitalstates]

Hi Jiri

can I suggest that the same post on 2 threads in the same section stands a good chance of confusing people...and diluting your response......

just a thought

Ed

[Toppsy]

Hi Jiri,

As Ed Swift (vitalstates) has mentioned on the other posting you made, Rob Mackinlay works away from home during the week so it may be a day or so for him to get around to answering your queries. He will answer your emails and his advise is always very valid.

If you are only interested in 2-way panel speaker then again as Ed suggests the ESLIII may be worth a serious consideration. This has a central treble panel 50mm wide straddled by two identical 225mm wide bass/midrange panels. There are no crossovers as such to these panels as the width of them limits the frequency to each panel. You will just need to decide what crossover point to your subs you want and fix this into your active crossover.

The Acorn is a different beast and has three distinct panels that have series wired crossover resistors on the mid and bass panels. For a ESL this speaker delivers very good and detailed bass. The bass panel has a greater air gap between stators and diaphragm and is fed with a higher EHT voltage off the EHT supply so to move more air. So it may be worth trying this speaker without your subs first then decide if you want more bass.

However, I have tried active subs through a active crossover to the ESLIII's in the past and have not really bottomed out a seamless integration to the fast panels. The timing of the woofer always is that little slower the panels and one can hear this. The bass always lags behind the speed of the panels. Perhaps this was down to the woofer drivers I was using and my limited knowledge of speaker design. I used the Peerless 10" XLS drivers with a 200W Mos-fet amp.

I have attached a couple of photos of the ESLIII naked so you can see the panel arrangement and a photo of my ESLIII with built-in subs.

[Toppsy]

Jiri,

I have sent Rob and email inviting him to join our little forum and continue this thread on-line for all to enjoy and perhaps learn something new.

Colin

[JiriAU]

To Toppsy

Thanks for your reply I think that Rob mention that Acorn would work better for my future room which should be
8x5meters and the Acorn "can will" move more air.With the subs I really want to keep it there are few reasons for it
I was able to get them spot on regarding to integrated with main speaker have to mention that without DEQX that would be impossible.
the other think I'm recently using Crown Studio reference 1 amp and it has 20 000 damping factor 10HZ to 400HZ that means it is very quick
and hoping that it would keep up with the Acorn.Also I'm very happy with the sound when listening Opera,Jazz,Classical just don't want to go back
without them so keeping my fingers cross that it would work.

But we will see what Rob is going to say if he is going to read this it would be great.I do have a friends at Czech Republic where I come from also
living now in Australia I would like to apologize if my writing is not correct as I did not come from English speaking background.So I have Friends at
Czech and they are really interested at ER Audio.One friend who recently cancel his order for Magnepanu MG 3.6R as he likes the sound he has older model MG IIIa
Nevertheless I told him about the ER Audio and he is keen to try it just don't want to make a mistake as I think he has been saving for years to upgrade.He has
small room about 20M2 and not really in to the bass.I was suggesting to go for ESL III or ESLIIIb but I just don't know he told me yesterday that he would go for the
Acorns if quality and detail is better but not for Bass only.

I would like to apologize that I have started the same thread in the same section like ED advise me should I delete that one and keep this one only?


Just out of interest here is link for some of my project it is in Czech hi-fi forum but if you scroll down there're few pictures

http://www.f-sport.cz/hifi/index.php...=13&topic=2716

[Robmac]

Hi Jiri,

Toppsy has invited me to join in this forum to clarify some of the queries you have regarding the Acorn ESL's.

I do recall our telephone conversation from the middle of the year and at that time I think I recommended that you should bi-amp the Acorns given you already had all of the amplifiers, processors etc available to you. The sections would be a separate bass section driven by one transformer / amplifier and the treble and mid-range sections driven by another. In this configuration it is likely you will not need to add the subs because you can adjust the amount of L/F equalisation and amplitude via the processor. The kit would need an extra transformer for the bass section as the Acorn panels are currently driven from one transformer via a simple resistive filter. I also recall that I recommended you keep the crossover point low, around 180 to 200 Hz to avoid creating problems with the vocal frequencies, where we are very sensitive.

Your Whise subs (very good choice incidently) if you choose to use them, should crossover at around 60 to 100 Hz leaving the panels to do the rest.

As the ESL bass section is no longer reproducing very low frequencies the distortion levels which are already very low, will improve. This is because the diaphragm is no longer expected to reproduce say 30 Hz (large excursion) and say 600 Hz at the same time.

The mid-range section and treble strip which are driven together will retain the passive filter between them but will also improve slightly because the transformer is no longer handling bass frequencies.

With the impressive array of equipment you have at hand you should be able to set crossover points and levels to give excellent performance.

Re the ESL III and IIIb. Both of these ESL's are very good performers in small to medium rooms but will be thin in the room size you are using. While you can add a transformer to these designs to bi-amp and improve bass output, there is a limit to the max SPL you can achieve. This is due to the air gap between the diaphragm and the stator. The ESL III / IIIb has approx 2.2 mm air gap which sets the maximum diaphragm travel. The Acorn has a 3.2mm air gap, a much longer and a slighter wider bass panel so is able to move much more air than the ESL III.

It's a while since I made any entries on a forum such as this as I do have a vested interest in our products and I don't want to be seen as using a forum to market them. However, I am quite happy to answer any queries regarding our products or give any advice (where I'm able to) about any other ESL's. Over the last 20 or so years we have had lots of experience with most makes so your questions are welcome.

I don't always get the chance to log-on to these forums on a daily basis as I do a lot of travel, however, I will always answer.

Best regards to all from very hot Oz

Rob

[JiriAU]

To Rob

Thank you for your reply I do now understand completely the active setup with your Acorns.I will contact you to organize it all.
Maybe one more question I do intent to make the enclose from still and wood particularly the top and bottom base is going to be made
out of 50mmm MDF(latter painted black metallic) than 2 pipes 50 mm diameter with U shape channel welded on to it.I'm intent to make the channel slightly bigger
so I could use a foam glued inside the channels and that would give me nice tide fit for the panels.On the end I would like to have the steel pipes chromed when completed that should end up with nice finish.My question is can you see any problem with mine idea of enclosures or Is there something I should be aware of .

I might just add that I really like the idea of crossing the bass panels at let say 200Hz to 80Hz where I mine subs kick in.I have had a lot of conventional speakers drivers where crossover point was usually from 3000 to 4000.and that never sound "properly".Only when good and expensive ribbons where used I could cross 1600 and even 800hz and that made really difference so crossing panels at 200Hz should be really good.

Once again thanks for your advise.
Jiri AU

[Toppsy]

Jiri,

I have attached a photo of my Acorn enclosures should you be interested. They are made from solid European OAK and do have 25mm x 5mm neoprene foam glued to the inside of the frames to give a snug tight fit to the panels. This works really well.

If you want more info on the construction let me know. I have promised this info with plenty of close up photos to another OZ Acorn constructor and hope to put this all together as soon as I get some decent daylight to take the photos.

Regards

Colin

[Xacity]

Hi Toppsy,

I came across the Acorns after visiting the site on a lead from an ebay auction for Quad repairs.

The Kit appeals as the Acorn goes up and not outwards like older quads. How sensitive have you found them to room positioning as this has to be a consideration in domestic surrounds? The Q&A section on their site does not mention this so I would be grateful if you could relate your experiences.

Regards

Xacity (tenacity)

[Toppsy]

Hi Xacity,

the Acorns don't appear to be too sensitive to room positioning but they need a minimum 1m behind to wall and 0.75m to the side wall. They are best fired down the room with toe in. These are the only ESL speakers I have heard that one doesn't loose ambiance of soundstage whether sitting or standing and go low enough not to warrant a subwoofer. They need an amp that can deliver high current at 2-ohm. So most (it not all) valve amps with at least 18W per channel in your average UK room is OK. I use a 45W gm70SE monoblocs and these drive the speakers very well indeed.

If you're anywhere near Rossendale, just North of Manchester, come over and have a listen. Failing that I'll most likely be taking them to the next WDFest whenever that may be. Steve Sheils usually organises these.

Regards

Colin