[scorpion]

I am sorry guys, it will be a bit longer till I am fit for some wood work. I have had a couple of bad weeks with flu and infection
setting me back a bit more than I first expected. But it is getting better. 

/Erling

[SteveFord]

Well, okay, but don't go making a habit of it.

[scorpion]

Infact I don't/didn't like it at all, I'm afraid.
/Erling

[studiotech]

Infact I don't/didn't like it at all, I'm afraid.
/Erling

Be well Erling, we'll all be patiently waiting for you.

Greg

[sfdoddsy]

Infact I don't/didn't like it at all, I'm afraid.
/Erling

The ESL or being sick?

[JohnR]

With regard to using the ER mini panels as mids, josh358 says:

Yes, the three-panel ones. Unlike on the single-panel Maggies, the midrange is a separate driver, in its own panel next to the ribbon tweeter, and it's the weakest range. It comes out as a unit and leaves a nice slot. When the mids died on Satie's Tympani IV's, he replaced them with a line of six Neo-8's with excellent results. So I've been planning to do something similar with my IVa's using the Neo 8's, 8s's, or 10's -- but since it will be a while before I can do this I'm open to other possibilities.

The IVa's woofer crossover is actually unusually high, between 250 and 400 Hz. (There's also an acoustic crossover between the low bass and midbass panels, so in a sense it's a four-way system.)

Sorry it took me a while to get back to this. From what I understand from Rob, the panels were designed to allow easy connection of two stacked, with the connections brought out the other end to allow a short wire to connect to a second. I haven't verified this on my pair.

I was actually making good progress with baffles today until an afternoon storm... 

From what you're saying four stacked would be ideal - ? On that, I have no idea on the best configuration. 'stats do need a power supply and HV transformer.

[JohnR]

Finally, some progress, first prototype baffle, courtesy of Ikea:



If you look close you can tell that I'm on a bit of a "learning curve" with rectangular holes... circles are so much easier! Well, off to do the second one, hopefully a bit neater this time.

[michael green MGA]

Hi John

I see your using a lighter weight particle board and not the dense MDF. Personally I think that is a good move . Don't know if you treat the cut outs at all, but with the more porous particles I like using water base varathene on it 3 coats. Gives a nice balanced tone. Also helps with the screws not riping out the particles.

looks cool

[josh358]

With regard to using the ER mini panels as mids, josh358 says:

Sorry it took me a while to get back to this. From what I understand from Rob, the panels were designed to allow easy connection of two stacked, with the connections brought out the other end to allow a short wire to connect to a second. I haven't verified this on my pair.

I was actually making good progress with baffles today until an afternoon storm... 

From what you're saying four stacked would be ideal - ? On that, I have no idea on the best configuration. 'stats do need a power supply and HV transformer.

I'm thinking a series/parallel arrangement could work for four.

BTW, if you're having trouble cutting holes, have you considered Baltic birch ply for your baffle? It seems to be preferred these days by speaker designers and it's easier to work with than particle board.

[hum4god]

I'm thinking a series/parallel arrangement could work for four.

BTW, if you're having trouble cutting holes, have you considered Baltic birch ply for your baffle? It seems to be preferred these days by speaker designers and it's easier to work with than particle board.

here is an answer i got earlier from ER Audio's Rob


4 panels per channel would only be required for quite large venues. You have a couple of choices how to arrange them. If you know you are going to use 3 panels in an array then I would advise not using the inbuilt transformers, instead you would use the Mid / Treble Acorn transformer we advertise on our website. This will happily drive 3 panels without HF roll-off. We are getting some separate HV supplies so this can be done quite easily (you're not the first to ask!!).
 
If you are driving 2 panels you can use the inbuilt transformers and connect them in series, this will give a nicer impedance for the amplifier to see and the transformers are consistent enough to avoid asymmetric voltage sharing.
 

 
Best regards
 
Rob

[JohnR]

BTW, if you're having trouble cutting holes, have you considered Baltic birch ply for your baffle? It seems to be preferred these days by speaker designers and it's easier to work with than particle board.

Hi Josh, these are just a prototype using cheap (or free, it was sitting in the spare room) material. It's not the material that's the issue it's me forgetting to add 12mm to the scale on the jig because of the router bit size. Anyway I'm getting there, the second one is much neater, should get the supports finished up today.

I'd love to use BB for the final one but I haven't been able to find any.

[josh358]

here is an answer i got earlier from ER Audio's Rob


4 panels per channel would only be required for quite large venues. You have a couple of choices how to arrange them. If you know you are going to use 3 panels in an array then I would advise not using the inbuilt transformers, instead you would use the Mid / Treble Acorn transformer we advertise on our website. This will happily drive 3 panels without HF roll-off. We are getting some separate HV supplies so this can be done quite easily (you're not the first to ask!!).
 
If you are driving 2 panels you can use the inbuilt transformers and connect them in series, this will give a nicer impedance for the amplifier to see and the transformers are consistent enough to avoid asymmetric voltage sharing.

Thanks, hum4god. Three might actually work, I'd have to measure the height of the midrange driver to make sure -- the speakers are 72" tall, meaning four panels is pushing it (68") while three panels would come to 51". The tweeters are 57" tall.

[josh358]

Hi Josh, these are just a prototype using cheap (or free, it was sitting in the spare room) material. It's not the material that's the issue it's me forgetting to add 12mm to the scale on the jig because of the router bit size. Anyway I'm getting there, the second one is much neater, should get the supports finished up today.

I'd love to use BB for the final one but I haven't been able to find any.

Hi John,

It seems you can order Baltic birch ply online, I'm not sure what the quality is like or whether these prices are reasonable, but I found some sources in Google:

https://www.google.com/search?q=baltic+birch+plywood&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a

[JohnR]

meaning four panels is pushing it (68")

You need a bit of space between them for the terminals too, not a lot (10mm) but if space is tight...

[JohnR]

Hi John,

It seems you can order Baltic birch ply online, I'm not sure what the quality is like or whether these prices are reasonable, but I found some sources in Google:

https://www.google.com/search?q=baltic+birch+plywood&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a

You're right! Found a place not too far from me, $128 for 18x1200x2400 plus delivery. Wil go have a look at it, he says it's B surface grade.

[tnargs]

I would have thought the less panels the better. Unless you are sitting in a very far field.

[JohnR]

Hm. I'm not sure - ? You will get a downward tilt in FR with more panels, which would need to be corrected, but other than that more panels would mean higher output, lower crossover frequency, and a larger vertical listening window. More money too Thanks for keeping it real I think I'll be happy with the one, although yet to see, I do not like woodwork!! But it's mostly done now, almost ready to start on the wiring.

[josh358]

You're right! Found a place not too far from me, $128 for 18x1200x2400 plus delivery. Wil go have a look at it, he says it's B surface grade.

Excellent! I'm not sure what B surface grade means, I'm no carpenter. But I hope it works out.

[josh358]

I would have thought the less panels the better. Unless you are sitting in a very far field.

Definitely for JohnR's project, but in my case I'd be replacing the midrange drivers in my Tympani IVa's, which are line source dipoles. So you're always sitting in the near field vertically, since the floor and ceiling reflections extend the array, and you want to be in the far field horizontally. I'd keep the 3 kHz crossover to the ribbon tweeter so that would be the case as well.

The alternative, which Satie here has done with great success, is using the BG Neo planar drivers to replace the midrange. They're apparently quite close to stats and true ribbons in quality, though not quite their equal.

Ideally, I think I'd build two narrow electrostatic strips and put them on either side of the ribbon, or make one 2" ribbon assembly with the tweeter ribbon flanked by two 1" midrange ribbons. But as things now stand, I don't have the time for projects of that magnitude.

[JohnR]

Finally! First pair of prototype panels are made:



Rob actually suggested mounting the panels from the back, but I was worried about the flimsy material so I did it from the front. But then I had to add some moulding anyway to hold it in, so next time I'll try it from the back.

There's something definitely cool about a speaker you can see through.