My experiences with planar speakers

[aechmea]

Here are a few of my thoughts regarding the electrostatic speakers and planar-magnetic speakers that I have owned and lived with.

It's really a bit of an apples and oranges comparison though since my room wasn't treated in ESL days and the stats certainly didn't have the same amplification or front end of the Magneplanars. So its no surprise that my recollection of the stats is of a lighter speaker in a brighter room. Indeed the stats and Maggies may be more alike than not, especially when considered against a traditional design, all of them in today's room.

Electrostatics

I bought Acoustat III in 1983 and kept them for 25 years.

They were very nice indeed and I liked mine better than some other models of electrostatics and early Maggies that I heard at friends' places in the early days. Being full range panels with no cone woofers, there was a sense of coherence and completeness about them.

To characterise the sound I would probably say that they had a fizz and sparkle about them, transparent and delicate, attack was obvious and there was plenty of mid range shimmer (well, 'shimmer' are highs but they sort of merged and floated with the mids). I liked the sound of say flutes, sopranos, the right half of a piano key board ie stuff above ~500Hz. The lower registers were clean, fast and accurate but lacked extension and weight against what I consider normal these days.

In recent years I have started to prefer more substance to my sound.

I tried adding a sub to the electrostatics and was happy enough at the time but looking back it wasn't in the same ballpark as what I have now with subs and Maggies and digital XO with timing, XO slopes etc.

The Acoustats were 3 full length panels per side with the 2 outer panels angled a few degrees off the square axis. No doubt to spread the dispersion pattern a bit, cf. some Martin Logans with a curved panel. However this directionality has never been an issue for our household since none of the inhabitants share any musical taste, meaning that there is only ever one person in the room at a time. A single listening chair is all that is needed, so directional or not, it doesn't matter to us.

Magneplanar 3.6R

Even though Maggies and stats share the same shape their sound is quite different. The Maggie 3.6Rs that I drove in active bi-amp mode have plenty of extension to 40Hz or so and therefore there is much more to be heard and felt below middle C. Its not wall wobbling and window rattling stuff but certainly adequate for most musical content.

I am unsure what words to use for the 3.6 sound; maybe clean, clear, pure, dynamic, full range, transparent (but not so transparent as the stats). They do bright metallic and percussive sounds very well (cymbals, Tubular Bells, harpsichord, Spanish guitar) without fuzz, coarseness or ringing, to go with the left hand piano, oboe, cello type rich stuff where they do a great job. May not have quite the presence of stats but make up for that with smooth extension both ways and a bit more weight = genuine full freq range speakers. Maybe a bit fuzzy in the mid range.

The 3.6Rs are 3-way with the bass and mid range drivers on a single sheet and the highs done by a 1.5m ribbon. Bi-amping is easy and encouraged simply by removing the external cross over box. There is another passive XO inside the speaker between the mid panel and the ribbon. Some people tri-amp by bypassing this XO too.

The 3.6R has recently been replaced by the 3.7 which has no ribbon and cannot be bi-amped.

Magneplanar 20.7

The 20.7s have all that the 3.6Rs had, but in spades, and a little more as well.

Perhaps the greatest single improvement is in the bass panel. There is a brooding menace about the speakers in that range. For example, Telarc 1812 cannons (not that I actually play any of this spectacular stuff normally) have all the thump and crack that you would want, whilst still maintaining connection with the rest of the freq range - and they give the impression that that was pretty easy really. Similarly for orchestral crescendos or rock music where everyone is bashing it out together. They don't seem to get lost no matter how complex it gets. Yet on the other hand they can be quite gentle and delicate with simple, relaxed or solo music.

Piano is fantastic - delicate in the tinkly bits but with power and intensity when that is called for. The piano actually sounds like a large instrument, with tone and timbre not just a point source in a soundstage. Maybe fair to say that all instruments have better dimensionality and scale.

There is little or no difference in the highs (the ribbon). Understandable since the ribbon module looks to be the same as in the 3.6R. Maybe not, though, because the magnet seems to be stronger. It has captured my tape measure a few times when it got too close. Dunno.

Also, the mid range is cleaner and sweeter than the 3.6s. I attribute the improved bass and mid range to double magnet layers and (I am lead to believe) a push-pull system on the panels and (I am lead to believe) the move of bass and mid range drivers onto their own separate sheets of mylar (or whatever the panels are made from). No need now for mids to piggy back on top of the lows from the same panel. This needs to be confirmed as I don't believe that this is written anyway with authority (and I am not going to take the covers off mine to look).

So the 20.7s are the same fast transparent panel style of sound, but with scale, size, power, richness and depth.

The only drawback is that they are no longer easily bi-ampable, so you run them with the factory passive XOs. I suppose that some enterprising person will one day attack the internals to active tri-amp, or replace electronic components with higher spec stuff, or replace the frames with hardwood or whatever .... as is the Maggie tweaker's way.

Planars and amps.

Electrostatics and Maggies are both inefficient designs (say 85 dB), they both have low impedance (say 4ohm) and in the case of electrostatics the impedance tends to fluctuate wildly. Both stlyes tend to be large and you tend to sit further from them, so you tend to find them in big rooms. All of these attributes mean that you should be careful with your amplification.

Amps have to have a fair bit of grunt just to get a reasonable sound pressure level but at the same time be able to deliver current to the low impedance. Even though some amps that I have owned, had what on paper seemed to be enough power, weren't that good in practice. Musical Fidelity A5cr (400 wpc into 4ohm) (thin and whispy) and Parasound A21 (400 wpc into 4ohm) (brittle and crystalline) were inferior to the Magtech (900 wpc into 4ohms) and, a blast from the past, an ME75 (200wpc? into 4ohm). Nothing quite like having amps specifically designed for a purpose.

Planars and room positioning.

There is a lot of comment re how difficult planars are to position in a room. Never found it that way myself. I just plonk 'em ~1.5m from the front wall, ~2.5m apart, toe-in to listening position which is about ~3m away and that won't be too far off. Tinker a bit from there. Probably exactly where you should place conventional speakers anyway.

Planars and subs.

There is also plenty of chatter that subs don't marry well with planars; that somehow the integrity of the planar is lost when married with a cone speaker. I can see how that can happen in some situations, but with the right equipment you can integrate subs (or woofers) quite nicely. I was never completely happy with my Acoustats with a sub, but at the time I didn't have the DEQX, measuring equipment nor experience. My preferred setting at the moment is to run the Maggies full range and have the subs overlap the bass panels a bit.

Summary

I guess that the true test is "if something gross were to happen that wiped out the complete system what would I replace it with?". In my case I think that I would just get the same components again such is my satisfaction with what I have. There are certainly better things out there but that would be getting into splitting hairs and diminishing returns territory. Hmmm as if I wasn't there already.

[sir sanders zingmore]

Great write-up aechmea, thanks for that.

Planars have always been my 'next' speakers

[Catostylus]

Thanks very much for that. There's plenty to think about in there.

 

I take it your 2 x Sanders Magtechs are the monoblocks?

[Rob181]

Great write up...tells it like it is & what is required to make a planner work...Rob

[Audionutz]

My Acoustat 6's were good with an ME75, but are now very good with an ME1500 .....

 

Cheers

 

'Nutz

[aechmea]

Thanks very much for that. There's plenty to think about in there.

 

I take it your 2 x Sanders Magtechs are the monoblocks?

Nuh, they are both the stereo ones.  Bit of a long story.

 

I had a stereo pair when bi-amping the 3.6R.  Wasn't quite as overkill as some would suspect since the XO between bass panel and the mid panel and ribbon combo was at 300Hz which is roughly the 50% power divide in a speaker so the same powerful amp for the top half was a valid choice.

 

So with the non bi-ampable 20.7s coming along I had a 'spare' stereo amp.  Too new to sell so I investigated ways to make use of it.  

 

Talks with Bill Maclean suggested that bridging using split/crosswired balanced cables worked.  

 

Discussion with Roger Sanders revealed that he would convert the ones that I had to internal factory bridged for free provided that I sent them back to the US.  Roger would also have swapped my 2 stereos for 2 monos even though they were 12 months old.  Fantastic offers from Sanders - he is happy also to have detailed email conversations and so on.

 

Anyway I decided to keep the 2 stereos and bridge them with the balanced cable trickery.  Deep in my subconscious I harbour this idea that one day there may be an opportunity to bi-amp or tri-amp the 20.7s.  In the mean time i'll run in bridged configuration and keep all 4 channels working and warm.  The Magtechs can drive an impedance of 0.25 ohms, so bridging is safe, and I can't hear the difference between bridged and not, so all is good, even if a little unusual.

[Catostylus]

Thanks for your answer. I realised later they couldn't have been the monos.

 

Yet another positive tale about Roger. I have a deep suspicion he's going to get my money one day.

[sir sanders zingmore]

Roger is a good man.

I'd love to hear his electrostats but I'm a bit scared to

[Ando]

Aechmea, Good summary advice about planars. My thoughts/experience closely follow  yours .  I think the excellent sound of your current system indicates the value of knowing what you want and following through by optimising the major contributors .

Why do you say 3.7s dont have a ribbon ?

Cheers Mike

[Nigel]

Nice write-up Peter,

re runnng the Maggies full-range with subs overlapping... what is the range of the bass panel ?

On one hand the Maggies contribute 2 subs and the actual subs mean a total of4 fora multi sub arrangement. Paul Spencer recommends for good bass.

If the bass panel goes high, like >500Hz, I would suggest taking the large excursions off it to clean up the upper freqs on that panel.

Not sure a single listener needs a multisub aproach to provide even bass throughout the room.

I can't remember how much EQ you are using, but have you tried the current set-up without the DEQX?

[aechmea]

Aechmea, Good summary advice about planars. My thoughts/experience closely follow  yours .  I think the excellent sound of your current system indicates the value of knowing what you want and following through by optimising the major contributors .

Why do you say 3.7s dont have a ribbon ?

Cheers Mike

Hi Mike,

 

The 3.7 and 1.7 have what Magnepan call a "quasi ribbon" where the ribbon is 'glued' to a mylar sheet.  All the drivers in 3.7s and 1.7s are "quasi ribbons".  This makes the tweeter heavier but on the other hand more durable.

 

"True Ribbons" as in the 3.7, 3.6R, 20.1 and 20.7 are free-ish Aluminium strips attached at the ends and at alternate intervals down the edge that vibrate in free air without a backing sheet.

 

I think that AndyR's Magnefranks (or are they Frankenmags) have a true ribbon too.

 

[edited out 3.7 s being all quasi ribbon]

Edited January 5, 2013 by aechmea

[PixelPlay]

The 3.7 definitely has a true ribbon on the tweeter and quasi ribbons on the rest.

[aechmea]

The 3.7 definitely has a true ribbon on the tweeter and quasi ribbons on the rest.

Yes Yes.  Sorry.  Oops.  It's the 1.7 that is all quasi ribbon and as you say the 3.7 is true ribbon tweeter and quasi ribbon others.

[aechmea]

Nice write-up Peter,

re runnng the Maggies full-range with subs overlapping... what is the range of the bass panel ?

On one hand the Maggies contribute 2 subs and the actual subs mean a total of4 fora multi sub arrangement. Paul Spencer recommends for good bass.

If the bass panel goes high, like >500Hz, I would suggest taking the large excursions off it to clean up the upper freqs on that panel.

Not sure a single listener needs a multisub aproach to provide even bass throughout the room.

I can't remember how much EQ you are using, but have you tried the current set-up without the DEQX?

Hi N,

 

The problem with the bass panels as subs is that they are positioned where the mids and treble sound best, which is not always where low bass sounds best.  Therefore I position the satellite subs so that they fill in the bits where the mains (acting as 2 extra subs) aren't at their best.

 

Yes.  According to Toole, Paul S and others, 4 subs seems the best solution for low bass.

 

Magnepan are not actually forthcoming re technical details of crossovers and construction of the speakers - I would love to find out what's inside them.  However assuming that the 20.7 bass panels cross over at roughly the same as the 3.6Rs then the cross-over to the mids will be about 250Hz.  Probably a narrow enough range to be OK.

 

I reckon that a single seat setup still needs multi subs.  Positioning subs can fill in nulls that EQ can't do.

 

I use 7 bands of EQ.  3 are to tame the major room modes at 24, 29 and 62, the others variously to cut the tops off other lumps, to fill a long low hollow, to add a 'loudness curve' for low listening levels, to add some mid bass thump for Mrs. A and various combinations of settings as my mood takes me.  .

 

Removing the DEQX is a major undertaking in that I would have rewire with RCA interconnects, remove amp bridging, find some way to feed the subs, setup the sub's DSP, find a DAC and a pre-amp, etc.  What I can do though is set up a 'pass through' profile that only feeds the mains. ie the DEQX only acts as a DAC.  No listeners have ever preferred this to one of the 'assisted' profiles.  'Pass through' is like a watercolour painting, whilst the calibrated profiles are more like a photograph - deeper colours and definite edges.

[aechmea]

Hey Whato and Cato.  I reckon that you two have planar disease really badly.  There is only one cure .....

[Catostylus]

As soon as I work through my current CX4F disease and move somewhere with a larger room. Could take years.....

[frankn]

I'd love to have a bigger room and 4 panel speakers (2 front, 2 side) + subs+deqx.  Need to find the right house....so I can have a room away from the family