analysis epsilon

[DAMIC]

Hi,

I'm a total noob in planar theory. What's the rationale for non-parallel long sides (highlighted in the attachment) on your larger designs? This seems to be prevalent in a lot of planar speakers.

The shape with non-parallel longer sides simply gives the best frequency response on dipole speakers. Yu can check or simulate with Edge program :

Home of the Edge

regards,

 

[ApogeeLover]

trapezoidal design

Hi,



The shape with non-parallel longer sides simply gives the best frequency response on dipole speakers. Yu can check or simulate with Edge program :

Home of the Edge

regards,

If that was the case, the bass panel could be rectangular like the tweeter...
But it's not is it !

 

[Few]

I'm a total noob in planar theory. What's the rationale for non-parallel long sides (highlighted in the attachment) on your larger designs? This seems to be prevalent in a lot of planar speakers.

My understanding is that Apogee used the non-rectangular diaphragm shape, along with tension that was set differently at the top and bottom of the diaphragm, to tune the diaphragm to different resonance frequencies at different heights above the floor. The point was to avoid one dominant and audibly intrusive resonance.

It is often suggested that using non-parallel diaphragm edges prevents standing waves but the notion that rectangles support drumhead resonances while other shapes don't isn't correct. The spectrum of the resonances depends on the shape but the resonances are there whether the edges are parallel or not.

Few

 

[YohY]

....but the resonances are there whether the edges are parallel or not.

Few

I'd agree that the resonances are not totally eradicated, but are suppressed to a large extent..

 

[Few]

I'd agree that the resonances are not totally eradicated, but are suppressed to a large extent..

I don't agree that they're suppressed to a large extent but since I don't have data handy that I can present to back up my position I'll leave it at that. If someone has information that clarifies the situation I stand ready to admit I'm wrong.

Few

 

[brian t]

Been a while since i repaired these but wanted to see over a few months how they would perform and am happy to say its been fine so if anyone else has the same problems its nice to know these can be repaired in the field although its taken me nearly a year to source all the suitable parts and fix .

 

[brian t]

 

[brian t]

An externally hosted image should be here but it was not working when we last tested it.

 

[JarreYuri]

I don't know if it is a visual illusion but it seems like You have no lateral tension over the membrane as the side rubber seems to be slacking. True?

I see that You left the upper and the lower suspension out!

 

[brian t]

As you can see i have replaced the factory bass diaphram frame with one of aliminium but this did make it a lot harder job so i would not automaticaly recommend this mod as the factory mdf /ali strip is much easier to work with.

 

[brian t]

Hi, no top and bottom suspension is there its just hidden behind the membrane i did not extend it as far out as the original as test i made seemed to indicate that the panel moved in a more linear fashion this way.

 

[brian t]

 

[tyu]

Thanks for the info..an pic...looks great ....how the sound?

 

[a.wayne]

Brian t ,

Could you describe how the returns are done on the bass unit , how are the mags arranged ? As it appears they are returning in the field ..

 

[brian t]

cheers, yep they sound great i suppose i would say that after spending a year fixing them! but no they have all the virtues of these type of speakers world class detail retrieval, leading edges of notes not blurred as with most normal speakers and the ability to start and stop much quicker also the lack of thermal compression with this type of driver is a real eye opener i dont think i could go back to box speakers, they dont offer trouser flappin bass if thats your bag but for most material they are fine.

 

[brian t]

a.wayne if you have a look at the start of this thread you will see a picture of the magnet layout i took if that helps.

 

[brian t]

on a different note when i was repairing these i had the diaphram on and off the speaker several times and this caused the panel to go open circuit, i traced it to a hair line crack in a couple of places, i tried silver loaded paint and conductive glue all a load of crap, just by luck i tried some aliminium solder and it worked a treat, just beware as i have tried other solders and they just would not take.

 

[brian t]

 

[tyu]

Vary good to Know....i have now a pr of Apogee stages...an as you say...even the esl are not up to what i like about the sound of all ribbon drivers...other panels like the magnepan come vary close....it just not the same....the Apogee have got to be ran with the right sounding amps an preamp to get the sound one wonts ....I like the stage best of all the Apogees...it can be moved an not start buzzing only 60lb.. it can be ran with 50-80watt tube amp as long as you add subes ......i think your base setup is more forgiving...in a good way..may be better than any of Apogees...seeing how the foil on the bass drivers goes under the wood frame...yours has the rubber..looks like the way to go....thanks for your time an giveing the step by step going.....goodluck

 

[brian t]

Tyu, i used to have stages until they shorted out my power amp blowing up the output stage when i had the volume up, i just found them too inefficient i was always keeping an eye on the volume level , i think the diaphram was just too heavy, dont get me wrong they were still great speakers and hats off to jason bloom for comming up with a unique design may be the bigger models were better never got the chance to try or a big enough amp to drive them, this is where the epsilon has an advantage it is so much easier to drive and ironically the larger models are even easier to drive.But the main point is the addition of suspension allowing the panel to move more freely .thats my take on it i am no expert there are more people here who have a grasp on planar technology who i am sure will be able offer a more accurate response.