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Nigel

Eraudio Minipanels 505 - Entry Level my foot.

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Nigel   

Some of you may know I’ve been playing with a set of Eraudios ESL3s for about 10yrs and love the sound. They don’t appeal to everyone as they are quite large, like many other panel speakers in order to drive low frequencies and are very directional. Anyway, a  few months ago I saw that Eraudio had developed a small “entry level†panel kit quite cheaply and  much smaller.  There are some  nice developments with them though. The already narrow panel is divided (electrically) into 3 narrower vertical strips, the centre of which does treble. By being narrow the horizontal dispersion is improved.  I decided to build a hybrid set as a second system, mating them  8†drivers in boxes. (+ a sub which I use for my big speakers, also hybrid with 8" drivers). Built a 2-way passive crossover by measuring and changing inductors and caps etc. Anyway its done now and it is a very sweet thing. It has been a few months since I unplugged my big speakers to play with these little ones and I’m in no hurry to unplug these little things. “Entry level†my foot - exceeded my expectations by a mile..   
Those of you with large panels (ESLs, Maggies and the like), I know you love them, but these are worth checking out, especially if your wife /girlfriend gives you grief about your big speakers.If you're in Sydney I’m happy to let you listen to mine,  just let me know.
 Ciao for now,
 

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NADMAD   

Hi Nigel,

 

Am I right in saying that the power supply supplied with the panels also acts as a high pass passive filter, presumably also crossing over the frequency bands to the respective panel strips? If so, would it be possible to bypass at least the passive high pass filter and use an active crossover in its place? 

 

Also, are you using single panels per side, or two stacked? Photos would be great!

 

Thanks, Tom

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Nigel   

Hi Tom,

 

I have a couple of photos, having trouble working out how to upload them.

 "Image" wants the photos via a URL, I have them in a folder on my laptop. I don't know how to close that gap.

I trust Rob answered your q's about crossover.

I am using a single panel on each side, with 8" bass driver underneath, (and a sub in the corner doing 25-45 Hz)... 

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NADMAD   

Hi Nigel, if you click "More Reply Options" in the bottom right hand corner it will bring up an option to upload a file.

 

Rob answered all my questions and more. It was fascinating to hear his insight into other manufacturer's ESLs as well.

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NADMAD   

Awesome! They look so funny with the monoliths in the background! Thanks Nigel. 

 

What crossover frequency and type are you using?

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Nigel   

Hi Tom,

 

the photos seem a little elongated, but the top of the big panels is just under 6', if that helps.

 

Ok I used measurements to decide IF I was going to add an inductor on the 2 available pins, or not.

Since I was always going to make "hybrids" with these panels, then it is usually better to have the panels (or any other driver) NOT go as deeply as they can, for a couple of reasons, and especially if you intend to give that responsibility to another driver anyway. 

 

So I decided to use a higher crossover point than the panels can do, up around 600Hz with a 1.8mH inductor.

 

Next the bass box - the 2nd order crossover is not a standard Butterworth , LR, Bessel or anything. Having lots of caps and inductors I tried mixing and measuring, change, measure, change measure, until it mated nicely with the panel HP on the graph. By doing this, the crossover was sorted, but also some room effects at or near the 600Hz crossover point were dealt with, without using an EQ device. The components were another 1.8mH inductor with a 68uF cap to ground.

 

One other thing, I have to thank @@scuzzii and @@Headbanger who heard them when first built. I hadn't bothered to measure them at that point and the lads gave great feedback that the bass box was a little too loud. So after a month or 2 I decided to do the job properly. I ended up cutting 4dB off the bassbox with an Lpad (2 resistors - again I looked at different amounts) and then did the iterative  measuring to set the crossover. I was surprised at the further improvement that exercise did.

 

 So from the bottom, I have set my sub to do 25-50Hz (using a miniDSP), 8"s do 50-600Hz, panels 600 - 16kHz.  But can be changed, you may prefer to crossver around 300Hz. In my room that wasn't as good. Good luck with it. Happy to answer any q's.

Edited by Nigel

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NADMAD   

Hi Tom,

 

the photos seem a little elongated, but the top of the big panels is just under 6', if that helps.

 

Ok I used measurements to decide IF I was going to add an inductor on the 2 available pins, or not.

Since I was always going to make "hybrids" with these panels, then it is usually better to have the panels (or any other driver) NOT go as deeply as they can, for a couple of reasons, and especially if you intend to give that responsibility to another driver anyway. 

 

So I decided to use a higher crossover point than the panels can do, up around 600Hz with a 1.8mH inductor.

 

Next the bass box - the 2nd order crossover is not a standard Butterworth , LR, Bessel or anything. Having lots of caps and inductors I tried mixing and measuring, change, measure, change measure, until it mated nicely with the panel HP on the graph. By doing this, the crossover was sorted, but also some room effects at or near the 600Hz crossover point were dealt with, without using an EQ device. The components were another 1.8mH inductor with a 68uF cap to ground.

 

One other thing, I have to thank @@scuzzii and @@Headbanger who heard them when first built. I hadn't bothered to measure them at that point and the lads gave great feedback that the bass box was a little too loud. So after a month or 2 I decided to do the job properly. I ended up cutting 4dB off the bassbox with an Lpad (2 resistors - again I looked at different amounts) and then did the iterative  measuring to set the crossover. I was surprised at the further improvement that exercise did.

 

 So from the bottom, I have set my sub to do 25-50Hz (using a miniDSP), 8"s do 50-600Hz, panels 600 - 16kHz.  But can be changed, you may prefer to crossver around 300Hz. In my room that wasn't as good. Good luck with it. Happy to answer any q's.

Thanks Nigel. Just out of interest, what's the internal volume of your cabinets? 

 

Cheers, Tom

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Newman   

With electrostatics, a good small one can beat a good big one at frequencies above its bass limitations. That's why these little demons have a lot to offer, and price is no indicator. I have the 440's (not set up at the moment), and even with a very sloppy temporary lashup, they showed something special. My brother-in-law with the Scan-Speak Revelator DIY boxes was completely astonished when listening to soprano with piano.

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"Entry level my foot".  Now there's a headline that is literally true.

 

Interesting post, too.  It is always nice to hear of value-based success.

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Nigel   

Hi Tom,

 

the cabinet volume is 41L or maybe it was 31L ?? can't remember.

I'll measure the external dims when I get home.

But I used an online calculator using the T/S parms of the Dai-Ichi driver to give a standard Q or .707 (I think it's called "Q"?).   

Doesn't look much but it works ok.

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scuzzii   

No way these are entry level.  Completely agree with Nigel.  They were a real surprise packet - and that was my verdict before wine!!!.  I've not been the biggest Electro static fan but these are singing with how Nigel has got them running.  Great job. 

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These are seriously good.  They have that open airy sound typical of ESLs.  I have had a few listening sessions with these and they do a lot right regardless of their reasonable price. Nigel paired these up with an 8" mid-bass speaker to fill in the lowish end not just so the thwack is there, but also to allow the panels to play a bit louder.  In fact plenty loud enough for me.  

 

The midrange & treble reproduce the subtleness of the recording room's acoustics, transients jump at you & the sound stage is full & realistic. 

 

I am surprised no one has mentioned the ER Audio panels with the miniDSP PWR-ICE125.  I would expect this to be a great match.

 

HB 

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NADMAD   

It's actually in the plan to add them to this project eventually. My only reservation is that I think they're class D so wouldn't really work with the panels.

Sent from my iPhone using Tapatalk

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@@Nigel Is there any sort of protection over the front of the panels? It is a little hard to see from photos, but I assume part of the grille is in front of the membrane? I'm interested in these panels but I am wondering how "child friendly" they are.

Cheers!

SS

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Nigel   

The diaphragm is sandwiched between (but not touching) 2 stators. (Standard ESL structure as per Wikipaedia) the stators have holes to let the sound out.

While the voltage/current is not dangerous (unlike earlier Quads which used much higher voltages), a child could poke something througth the holes and tear the diaphragm.

Many conventional speakers have been similarly damaged by children. A small hole can be lived with, but once it reaches a few ml it will reach the stators and need to be fixed. possibly a pices of sticky tape ro a cpml3ete re-diapragm, which is probably doable with some input from Rob Mac.

Better would be to put a 240v wire in front of the speakers to keep children at bay.

Really there are just a couple of years between children becoming capable of such damage to when they know better.Say 1 to 3 yrs old.

 

If you are wondering about the child being zapped by the panel.....

 higher voltage is usually required for larger air gaps (diaphragm to stator clearance) in order to drive bass. In these little panels, bass is not even attempted, so not relevant for minpanels. So again the security risk is protecting the panel not to the child.

Edited by Nigel

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Thanks Nigel. The kids are 5+ so it would only really be if they bumped against it accidentally (or a shoe gets thrown etc :rolleyes:). As the grille is in front of the membrane, they should be fine in our home. They know what not to touch of Dad's :D

 

Regards,

 

SS

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Grizzly   

"Entry level my foot".  Now there's a headline that is literally true.

 

Interesting post, too.  It is always nice to hear of value-based success.

 

I've seen Nigels' feet. I also have have trouble sleeping. Coincidence?

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Nigel   

Hi Bear,

 how's life down in Adelbrain ? The audio scene still thriving?

 My feet have changed, they are nowhere near as they were before, which is quite.

 

atb,

Nige

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ESLman   

Hi all, I'm new to this forum so if I breach any protocols, my apologies in advance.

 

I don't often visit HiFi forums for various reasons but a question regarding ESL safety relating to one of our products was raised so I thought I'd post a comment. The comment below is relevant for all ESL's.

 

The 505 panels are safer than most ESLs (especially some home made types) for a couple of reasons.

While the bias supply voltage sounds scary, 2.5kv in this case, the diaphragm is fed through a 100 megohm resistor that limits current down to a negligible level. While you can get a shock from the HV supply it's trivial, much like being zapped by your car door or a lift button after walking on nylon carpet, more of a surprise than anything.

The high voltage from the audio transformer is another matter, this is dependent on how loud the panels are playing and is directly proportional to the input voltage, remember, the input voltage from the amplifier is stepped up by a factor of 100, 20 volts in (very loud indeed) equals 2kv peak to peak expressed across the stators.

If you touch both terminals (front and rear stator) at the same time you will get a shock, possibly a serious one depending on how loud the panels are playing. The stators are comparatively safe, the conductive layer is on the inside and insulated so you have the thickness of the stator to isolate the live section. Touching the front of the panel while music is playing is not recommended but is normally OK. Touching both panels at the same time, especially with one hand on one and one hand on the other is dangerous, you may get an arc through the slots to your fingers or you could become capacitively coupled to the panel. The current will be directly across your heart so could lead to serious electrocution, not recommended. This is unlikely to happen but the risk is present.

It's important, not just for safety reasons, that the input terminals on the panels are covered so they cannot be touched or allow arcing to occur to the frame.

This is not unique to the 505's, all ESL's present the same problem, some more than others. The current Quad range of speakers have the conductive copper layer on the outside of the stators so place fairly dense grounded metal mesh screens between the outside world and the panel front and rear, they accept the acoustic compromise in the interests of safety.
ESL's with insulated perforated steel present some risk because you only have the thickness of the insulation to protect you. This can break down over time or through physical damage. I have seen some readily available commercial speakers with perforated stators arcing through the insulation to the frame. This can also arc to a finger if it's close enough.

Using grille cloth over the panel improves safety as it places an insulative barrier between the panel and the outside world. Alternatively a belt and braces approach is to use un-coated aluminium insect screen in front of the panel connected to ground, this stuff has minimal affect on sound quality. You can put grille cloth in front of it for cosmetic reasons and to prevent dust and insects getting into the works.

Naturally, items like the power supply etc should be enclosed in a box or inside the loudspeaker to prevent contact with prying fingers.

 

If anyone has any queries regarding this subject I'm happy to answer them. I can be contacted at [email protected]

 

Enjoy this fascinating hobby

 

Rob

 

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Welcome Rob. You and I have done business several times and I will attest to your generosity and depth of knowledge as being second-to-none.

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Thanks @@ESLman for the information.

If I do end up with a set of 505s I'll bear the warnings in mind. I am an electrician by trade and so have a healthy respect for higher voltages. :-)

Regards,

SS

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