possiblity of using multiple panels?

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drphoto

possiblity of using multiple panels?
« on: 1 Dec 2010, 01:38 pm »
It seems I remember reading (though never saw or heard) that back in the day, people used to stack two Advent Largers together for each channel. I think I've even heard of it done w/ Quad electrostats.

So could the same thing work w/ Maggie panels? A member has offered to sell me just the panels (drivers) from MMG's. I might still try to find a compete pair too in order to compare my modifications to stock (and have a pair to listen to in the interem) and that got me to thinking about a stack. Now I'm sure you can't just wire them in parallel, if both crossovers were in place, as the impedence would drop too low, but could one crossover handle both, or would it need to be completely redisigned by a knowledgable crossover artist?

Or is my lack of sleep from working 3rd shift just melting what remains of my brain?

cheers

BobRex

Re: possiblity of using multiple panels?
« Reply #1 on: 1 Dec 2010, 02:00 pm »
Well, yes you could stack Maggies.  The total height eventually becomes an issue, but double MMGs would work.  As far as the crossover is concerned, I would suggest instead of parallelling the speakers (giving an aggregate load of 3 ohms - a difficult load for most amps) you run 2 similar amps and vertically drive the panels - one amp driving each channel.  I believe this was originally done with the stacked Quads (ESL 57s BTW, anything from the 63s forward may not be successful given the point source radiation pattern). 

Mucking with the crossover is tricky.  Crossover values are designed around not only the frequency and slope, but also the load value.  Changing the load (as you would by parallelling panels) means you either need to recalculate the component values or accept the shifted crossover frequencies. 

BaMorin

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Re: possiblity of using multiple panels?
« Reply #2 on: 2 Dec 2010, 03:33 pm »
It seems I remember reading (though never saw or heard) that back in the day, people used to stack two Advent Largers together for each channel. I think I've even heard of it done w/ Quad electrostats.

So could the same thing work w/ Maggie panels? A member has offered to sell me just the panels (drivers) from MMG's. I might still try to find a compete pair too in order to compare my modifications to stock (and have a pair to listen to in the interem) and that got me to thinking about a stack. Now I'm sure you can't just wire them in parallel, if both crossovers were in place, as the impedence would drop too low, but could one crossover handle both, or would it need to be completely redisigned by a knowledgable crossover artist?

Or is my lack of sleep from working 3rd shift just melting what remains of my brain?

cheers

I positioned 2 pairs of MG1's  (improved and 1.4s) side by side. Drove them with a pair of ampzillas. In that room, the outside pair ran zero toe in, tweeters out. the inside pair were toed in between 7-11º tweeters in.  Huge soundstage. Im not sure you would get the same by going verticle.

raindance

Re: possiblity of using multiple panels?
« Reply #3 on: 2 Dec 2010, 03:56 pm »
Two 4 ohm speakers in parallel gives 2 ohms... Not a good load for most domestic amps (unless you are in a car). Most of the Maggies are 4 ohms.

I've tried it with two pairs of MMG's connected in series. This gives a benign 8 ohm load to the amp. Side by side there is tremendous warmth in the lower registers. The imaging gets shot to hell though and you end up with a diffuse sound stange. The only way to snap the imaging back in place is to get all the tweeters in line (after all a planar is a line source), so stacking them should work. I'm not sure how much good this would do you though, as you aren't anywhere near 8 feet tall when seated and you'd need some fancy stands to keep them from falling over.

Personally, I'd be more inclined to take single MMG's and mount them to "bass modules" or small sub woofers that are able to support them. I'd love to hear from anyone who has tried this.

SteveFord

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Re: possiblity of using multiple panels?
« Reply #4 on: 3 Dec 2010, 01:13 am »
I've never run them stacked like you're thinking about or even side but side but years ago Carver had a delay and small amp built into his C4000 and C4000t preamps.
I ran two MMGs up front with two MMGs as delay speakers in the rear (with a much lower volume setting) and sitting in the center of all of those Maggies gave really good sound with just normal two channel recordings.
MMGs affixed atop subs sounds like an interesting experiment.

Rusty Jefferson

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Re: possiblity of using multiple panels?
« Reply #5 on: 8 Feb 2011, 04:26 am »
This is my first time through the Planer circle, and I came across this thread. I don't own Planer speakers, but just had the opportunity to audition some equipment at a new acquaintance's home and he had 2 pairs of 3.6Rs in a "T" configuration, wired in series. By "T" I mean each channel was 2 speakers in a "T" shape. One panel facing the listener, and one panel at a right angle to the first.

I'm not sold on Planers by any means, but the soundstage in his room was like nothing I had heard before. Amazing placement of the musicians, and the "Sweet Spot" was about 10 feet wide. I'll see if I can get a picture of his room. Others using this technique?

raindance

Re: possiblity of using multiple panels?
« Reply #6 on: 8 Feb 2011, 11:45 am »
This is my first time through the Planer circle, and I came across this thread. I don't own Planer speakers, but just had the opportunity to audition some equipment at a new acquaintance's home and he had 2 pairs of 3.6Rs in a "T" configuration, wired in series. By "T" I mean each channel was 2 speakers in a "T" shape. One panel facing the listener, and one panel at a right angle to the first.

I'm not sold on Planers by any means, but the soundstage in his room was like nothing I had heard before. Amazing placement of the musicians, and the "Sweet Spot" was about 10 feet wide. I'll see if I can get a picture of his room. Others using this technique?

Rusty
I wouldn't call this a technique - it doesn't make sense. It must mess with the dispersion characteristics and cause lots of cancellation of frequencies. Planars already suffer from lots of comb filtering; this would exacerbate the issue.

Rusty Jefferson

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Re: possiblity of using multiple panels?
« Reply #7 on: 8 Feb 2011, 02:34 pm »
Rusty
I wouldn't call this a technique - it doesn't make sense. It must mess with the dispersion characteristics and cause lots of cancellation of frequencies. Planars already suffer from lots of comb filtering; this would exacerbate the issue.

Again, I have little first hand experience with Planers. All 4 panels are the same distance from the listener. I assume the comb filtering effect you're referring to is from the reflected sound time delay?

Just thought I would mention seeing this done. Curious if others do, as I've never seen it done before. Besides the amazing soundstage, the bass response was better than any (only heard a couple) 3.6R set-ups I've heard without the use of subs.

I'll see if I can get a picture of the system.

flintstone

Re: possiblity of using multiple panels?
« Reply #8 on: 8 Feb 2011, 03:15 pm »
Always fun to play around with different ideas........it keeps the hobby fresh  :beer: This picture is looking at the question from a different angle (but still multiple panels).

Apogee Scintilla on bass, Apogee Stage on midrange, and not a panel, but Hill Plasmatronics taking care of the high freq's......oh, and a room full of some of Krell's finest for support  :thumb:






Dave



flintstone

Re: possiblity of using multiple panels?
« Reply #9 on: 9 Feb 2011, 01:41 pm »
This guy just had to hear stacked Apogee Stage, and it looks like he went to a lot of work to do it (the Stage are heavy little buggers).






Dave

oboaudio

Re: possiblity of using multiple panels?
« Reply #10 on: 9 Feb 2011, 06:29 pm »


I use Martin Logan Summits (woofers disconnected) along side of Magneplanar Tympani IV bass
panels (modified).  Combining the best properties of each speaker (electrostatic midrange and highs (no xover) and the Tympani IV bass.  The result of this combo is fantastic imaging, low level
detail and great depth and a huge sound-stage.  The Magneplanar Tympani bass panels are bolted
together and to the floor for bass that is very powerful, well controlled and has great transient
response. 
« Last Edit: 14 Feb 2011, 02:01 am by oboaudio »

oboaudio

Re: possiblity of using multiple panels?
« Reply #11 on: 9 Feb 2011, 10:56 pm »
I use Martin Logan Summits (woofers disconnected) along side of Magneplanar Tympani IV bass
panels (modified).  Combining the best properties of each speaker (electrostatic midrange and highs (no xover) and the Tympani IV bass.  The result of this combo is fantastic imaging, low level
detail and great depth and a huge sound-stage.  The Magneplanar Tympani bass panels are bolted
together and to the floor for bass that is very powerful, well controlled and has great transient
response.

BrassEar

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Re: possiblity of using multiple panels?
« Reply #12 on: 9 Feb 2011, 11:39 pm »
I have doubled-up on various Maggies over the years.

Stacking them will give you an excellent line source sound but side-by-side you get greatly increased impact via killer midbass and midrange.  I ended up running them side-by-side with the inside tweeters disconnected. I use pro amps so 2 or 3 ohm loads are no sweat.  If you think this won't work google Magnepan Typani and the concept is obviously valid.

josh358

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Re: possiblity of using multiple panels?
« Reply #13 on: 19 Feb 2011, 02:46 pm »
If you use them side by side, you want to disconnect and short the tweeter strip on one and use a 2-1/2 way crossover so that both speakers handle only the bass frequencies. The idea is to keep the width of the drivers small compared to the wavelength of the highest frequency they're reproducing, and to avoid interference patterns.

If you use them vertically, this isn't an issue, but you won't get an SPL improvement.

It's probably also worth noting that putting them side-by-side will exaggerate the low frequency response (technically, it reduces Fequal) so you really need some kind of active EQ. Also that the MMG's are never going to have super bass, the frequency of the woofer resonance is too high and it isn't practical to lower it. So best I think to stack them vertically, as several have suggested. Another interesting possibility would be to strip the magnet assemblies out of one pair and use them to make the other pair push pull!

DustyC

Re: possiblity of using multiple panels?
« Reply #14 on: 19 Feb 2011, 03:50 pm »
Flintstone,
Were did you get that Lava lamp? :o

Rusty Jefferson

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Re: possiblity of using multiple panels?
« Reply #15 on: 17 Mar 2011, 02:09 am »
This is my first time through the Planer circle, and I came across this thread. I don't own Planer speakers, but just had the opportunity to audition some equipment at a new acquaintance's home and he had 2 pairs of 3.6Rs in a "T" configuration, wired in series. By "T" I mean each channel was 2 speakers in a "T" shape. One panel facing the listener, and one panel at a right angle to the first.

I'm not sold on Planers by any means, but the soundstage in his room was like nothing I had heard before. Amazing placement of the musicians, and the "Sweet Spot" was about 10 feet wide. I'll see if I can get a picture of his room. Others using this technique?

I did a little research into this set up, and the fellow who uses it was nice enough to let me take/post a couple of pictures.

I contacted Magnepan, and Wendell was familiar with variations of the arrangement that to the best of his recollection were sampled by the folks at Audio Research. He confirmed Audio Research used one of these variations at a CES at least one year, but couldn't be more specific.

The set-up in the photos was developed by Pierre Sprey at Mapleshade Records. I contacted him and he confirmed he began setting up Maggies this way after seeing some experiments done with Varying arrangements with Quad speaker placements. The speakers must be wired in series, not parallel, as a demonstration immediately showed the two sets of speakers running in parallel sounded sloppy and incoherent. The series wiring also adds substantially to the bass response and the high frequency dynamics. It's quite remarkable. I could sense no major flaws of time alignment or added comb effect.

As I originally stated the soundstage is huge, and musicians are perfectly placed on the stage. I would encourage others to try it out if they can.

This room is large. About 36'x28' with a cathedral ceiling.










Davey

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Re: possiblity of using multiple panels?
« Reply #16 on: 20 Mar 2011, 04:32 pm »
You say those are wired in series vice parallel.  I assume this is only because of lack of power amp capability to drive 2 ohm loads?

I can't tell by looking at the photo's but I'd be interested to know the polarity configuration.

Dave.

Rusty Jefferson

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Re: possiblity of using multiple panels?
« Reply #17 on: 21 Mar 2011, 12:11 pm »
You say those are wired in series vice parallel.  I assume this is only because of lack of power amp capability to drive 2 ohm loads?

I can't tell by looking at the photo's but I'd be interested to know the polarity configuration.

Dave.


No, the 2 ohm stability is a secondary factor. Wired in parallel, the two different pairs of speakers work (very slightly) against one another, as it's not possible for any two sets of diaphragms to work in perfect unison wired this way. Hence, there is cancellation of frequencies and muddiness. This would also be true with box speakers. But wired in series, the current works both pairs as if they were one large speaker pair. Both pairs of diaphragms working together. This accounts for the dramatic increase of bass response, and more high frequency dynamics compared to a single pair of speakers, or two pairs wired in parallel. The nominal 8 ohm impedance is a great benefit also for easing the load on amplifiers. This fellow uses a moderately powered tube amp (about 50 watts per) and it plays plenty loud in that big room.

I'm not sure what you mean by 'polarity configuration', but it's standard series wiring. Here's a diagram of series wiring vs. parallel. http://www.hometoys.com/htinews/jun05/articles/nigelb/speakers.htm

If you have two pairs of speakers, give it a try. With his 3.6Rs the ribbons of the 'second' pair of speakers are just to the listener side of the 'main' pair.

Davey

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Re: possiblity of using multiple panels?
« Reply #18 on: 21 Mar 2011, 02:13 pm »
If the main speaker woofers are moving toward the listener are the secondary woofers moving inward or outward?

It seems to me that with this configuration you'd want to "offset" the "T" so the main speakers intersected the secondary speakers at a point between their tweeter and mid/woofer.  I can't tell from the photo's if it's currently that way or if the "T" is symmetrical.

I have a second pair of MMG's and I will probably try this......although the concept seems silly because it ruins/aborts the nicely engineered dipole radiation Magnepan's exhibit.  This seems pretty "gimmicky" to me.  :)

Cheers,

Dave.

Rusty Jefferson

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Re: possiblity of using multiple panels?
« Reply #19 on: 21 Mar 2011, 07:21 pm »
If the main speaker woofers are moving toward the listener are the secondary woofers moving inward or outward?

It seems to me that with this configuration you'd want to "offset" the "T" so the main speakers intersected the secondary speakers at a point between their tweeter and mid/woofer.  I can't tell from the photo's if it's currently that way or if the "T" is symmetrical.

I have a second pair of MMG's and I will probably try this......although the concept seems silly because it ruins/aborts the nicely engineered dipole radiation Magnepan's exhibit.  This seems pretty "gimmicky" to me.  :)

Cheers,

Dave.

Dave,

I don't know/have enough experience with planer speakers to have knowledge of how they differ from box speakers with respect to rarefaction/compression waves. The 'front' of the 'secondary' pair is facing outward, and as I stated previously, the secondary pair appears to hit the main pair with the tweeter just on the listener side and the bass panel behind the main pair. If wired per the drawing (and first photo, though hard to make out) The rarefaction/compression will be the same on the 'front' side of both pairs. I don't know what happens on the rear side of this type of speaker,  :roll: i.e. same absolute phase, or inverted.

In this install, the speakers are appox. 10 ft. from the rear wall. Appox. 20 ft from left side, and maybe 6 ft. from the right side bay window. Maybe 8-10 ft. apart.

Appreciate your trying it out. You never know till you try things. He uses a clamp visible in the third photo at the top that's maybe for picture frames (?) that holds two pieces of wood in the "T" configuration.