Planar speaker placment guide!

[Florian]

Between the direct radiating speakers and dipol systems are some great differences: The full frequency spectrum is not only radiated to the front but also to the back! The rear wave has a enourmas impact on the sound quality. The sound is reflected by the rear wall and is added with a time delay to the direct sound.

The amount of time delay decides by the high end dipoles (fullrange) if the recordings are reproduced with a stunning realism and stage width and depth or if they make them sound horribly unprecise and muddy! The term make it or brake it, really applys to these systems.

If the reflections follow the direct sound in less then 3 milliseconds then the ear cannot differenciate between the two. Sound travels with 344 meter per second, 3 milliseconds are thereby 1m.

Is the in-direct sound forced to travel less then 50cm to the backwall and back to the speaker, then it will heavily influence the sound in a negative way. Short impulses will be altered and fakely enlarged (made longer), which then causes the recording to be dirty, unprecice and softly rendered. That however changes when you give them lots of room to breathe. 70cm are the bear minimum and 1 to 1.5 meters are a lot better.

In a good concert hall, the soundwaves will arive at least 10 milliseconds later then the direct sound waves. That is a difference of 3.5m! That is a distance that we usually cannot place dipoles in our homes (space, waf etc..) since that would take aprox 2m from the backwall in a typical home.

Dipoles can therefore only create the illusion that your in a small concert hall. But then again, is that nothing?

Here are some more requirements that you need to look out for with dipoles.

• Diploes must be placed 100% symetrically, otherwise they will sound different from one another.
• In its closer surroundings should be nothing reflective or absorbative. They should stand mostly free from boundries.
• Do not toe-in your diploes very much otherwise the reflective sound will come from left and right and not from the center which will decrease the dipol effect.
• Dipole bass systems are especially critical with placment! Place the center of the planar bass in a odd ratio to the sidewall. Ex: 1:3 (sidewall vs. backwall)

Well so much for the beginners guide to diplos from Florian!

[Florian]

I have written a Exel table where you can enter your room and speaker data. It will calculate the needed distances in order to keep an odd ratio so that you can place your dipole planar speaker correctly. Doing so with greatly improve transparency and bass responce. Klick here to download the small exel file.

http://www.apogeeclub.de/audioreview/ratio.xls

[E-Stat]

[*]Do not toe-in your diploes very much otherwise the reflective sound will come from left and right and not from the center which will decrease the dipol effect.

While I don't disagree with your overall concept, the best answer is to provide sufficient diffusion of the rear wave from the outset to provide the best imaging. I use a combination of bass traps and absorptive panels on the wall behind my 'stats. Toe in then can be optimized for the radiation pattern of the speaker. In my case, the Sound Labs radiate over a 90 degree pattern and stage width benefits from a much greater degree of toe-in than I used with my old Acoustats.

rw

[Florian]

I agree with your experience too, but in this case you own a electrostatic speaker. I think that the electrostatics dont have that bass hump which is evident on the planar magnetics like Maggies or the pure ribbon speakers like the Apogees. Also the panels are curved on the soundlabs so its a tad different ;-)

• The Maggies need a bit of a to-in in order to make up for the driver delay.

• Electrostatics are not my knowledge field but i am sure your guide will work wonderfully

• Pure ribbons like the Apogees need a reflective backwall with no toe-in for bass tuning and to smoothen outt the significant information below 25Hz.

[JoeE SP9]

With flat panel electrostatics such as my Acoustats there is a tradeoff between the use of reflections and the sweet spot. Flat electrostatics have a very small sweet spot. Toe-in is mandatory for proper tonal balance with panels of this type. Of course with toe-in there is a reduction of the "planar effect" so a compromise must be reached. The minimum amount of toe-in that puts you in the sweet spot is where one starts.Once you have the sweet spot nailed you can change tonal balance and tune the planar effect by moving your listening chair forward or back in 1" increments. You have what acts like a very subtle tone control. I have found this movement to be very helpful with CD's that have a peaky high end or other sonic aberrations. Forward movement helps open up lateral spread while simultaneously taming overly hot high frequencies. Backwards movement decreases lateral spread and tames overly hot high frequencies. Florian's suggestions about distance from walls and symetrical placement are dead on.

[Bones]

I have written a Exel table where you can enter your room and speaker data. It will calculate the needed distances in order to keep an odd ratio so that you can place your dipole planar speaker correctly. Doing so with greatly improve transparency and bass responce. Klick here to download the small exel file.

http://www.apogeeclub.de/audioreview/ratio.xls

Hi:

I entered the length and width of my room, and the height and width of my Martin Logan Ascent speakers. However, the excel spead sheet did not change values. Do I need to do something else? Does excel need to be running in the background?

[Florian]

That is strange, just enter your distance to the sidewalls and it will show up the odd ratios to the backwall. What i can really recommend for your Martin Logans, are dispersive backwalls :-)

[squeegy200]

Florian,

I've been using your spreadsheet as a guideline in arranging my listening room and my Magnaplanar SMGs in that space. These are much more sensitive to placement than my previous dynamic box speakers.

I've noticed that not only is listening position in relation to the speakers are important, that there are discernable nodes on the vertical axis as well. When I stand up I can hear different timbres and cancellations.

I've read several of the positioning arguements made by other owners and some are advocating lifting of the speakers off the floor.

Are there guidelines for speaker placement in the vertical axis?

[JoeE SP9]

All of the planar speakers I've ever owned or listened to had a different sound when standing unless they were substantially taller than the listener. Acoustat 1+1's and 2+2's do not have this problem as the are constructed to act as quasi line sources in rooms with 8' ceilings. Tilting your MMG's back on the stands will help with the vertical dispersion. Of course, using stands to raise them of the floor so that the vertical middle of the speaker is at ear height will go a lot further towards solving the problem. If I remember correctly, there used to be stands for Quad ESL57's that raised them off the floor because of the vertical dispersion problem.

[MOON]

I agree with E-Stat that the rear wave has to be diffused big time or else as already stated it bounces off the rear wall and back to the stator panel as in Logans which I own or the same with maggies.

I read an article in Sterophile a few years ago where they took a bi-fold slatted closet door behind the speaker on the wall with the door halfs slanting back to the wall at a 30% angle from the middle of the door where the hinges are . The hinge part is in line with the center of your speakers.

Prime and paint the slatted door the same color as your walls. You can use a spray can primer which will speed up the finishing process. It comes in white, and then paint them after.

The rear wave hits the slatted door and the wave is dispersed to the side and center of the room instead of going off the wall and back into the panel. This slatted panel works great and really will clean up the midrange and you will get better soundstage focus.

You can buy the slatted doors at any Home Depot store.

I also use slatted door halfs in the corners of my room also. Take the hinges off the 2 halfs of the doors, this gives you a panel for 2 corners. This also cleans up the sound as well.

The rear wave shouldn't be absorbed at all, just diffusion is whats needed. I agree , electrostats should be kept quite a distance from the rear wall. Mine are a tad over 4 ft from the wall.

If you own maggies or Logans, try this slatted door tweak, it will amaze you with the results , and it is cheap to do.

If anyone is interested , I will post the Stereophile article on the slatted doors.

Cheers, 1st post

Greg

[Feanor]

I agree with E-Stat that the rear wave has to be diffused big time or else as already stated it bounces off the rear wall and back to the stator panel as in Logans which I own or the same with maggies.

...
Greg

I found that a panel made of ceiling tile works very well indeed. I use a 2' wide panel place at about 35 - 45 degrees with respect to the speaker which deflects the sound outwards as well adsorbing some of the sound. See my picture here: the panel is partly obsured at left of the picture ...

http://gallery.audioreview.com/showp...sort=1&cat=500

I don't know that is is better than the folding doors, but it is simpler and cheaper. Note the the ceiling tile is unpainted.

[Florian]

Maybe i should add that for instance, a Maggie has a different rear wall requirement, then the Soundlab and they differ from Apogees also. Planars are not created equal ;-)

[JoeE SP9]

I have owned Magneplaners or Acoustat's since 1976. In every case in every room they did not sound right unless there was plenty of room behind them. At somewhere between 3 and 4 feet from the wall the sound opens up and the illusion of depth becomes very distinct. Moving too far away will increase this illusion but the bass response may be negatively effected.

[patpong]

I toe in my Apogee about 1".

[dimes]

Am I crazy?

I have a 20x20 room with a fireplace centered on one wall that bumps out about 4 ft. I'll be building cabinets on both sides to house components, media and main speakers.

Plasma or projection screen above the fireplace so where does the center channel go?
Above the TV is very high, below the TV raises the TV too high AND I'd want to build out the wall 4" to accomodate an in-wall speaker. Both issues are solved with....

Fairly large Planar speaker (or two) behind an acoustically transparent screen mounted in a nice picture frame. I get the TV as low as possible, the speakers behind the screen (perfect!) and I don't have to build out the wall to inset a speaker.

So I know the typical do's and don'ts of planar speakers and dipoles in general - away from the wall, toed in. BUT...

A center channel speaker isn't supposed to have a very wide sound stage so I thought tight on the wall won't be so bad. How awkward would having the backwave reflected so quickly back sound? I can also consider putting an acoustic panel behind the planar to help eliminate the backwave. I realize this is an inefficient way to drive a speaker as well since I'm looking to eliminate half the sound output. I also have no idea how well dynamat or similar products work. I realize not timbre matched to the mains speakers but I think I know I can live with that if everything works well and I can work hard with equalization to match as best as possible.

Back to the original question: Am I crazy?

[JoeE SP9]

In the first place a fairly large planar speaker is 5ft tall or taller. In the second place planar speakers require a 3 to 4 feet distance from the wall. There are slim line boxes designed for the position you have in mind. Since you are going to put the speaker(s) behind the screen and filter out half the sound why waste money on planars? Why not put a purpose designed center channel speaker below the screen? Many of them have the kind of low profile you're looking for.

[squeegy200]

In the first place a fairly large planar speaker is 5ft tall or taller. In the second place planar speakers require a 3 to 4 feet distance from the wall. There are slim line boxes designed for the position you have in mind. Since you are going to put the speaker(s) behind the screen and filter out half the sound why waste money on planars? Why not put a purpose designed center channel speaker below the screen? Many of them have the kind of low profile you're looking for.

I've not heard them myself but Magnaplanar makes a Home Theater setup with wall mounted planar speakers. There is a picture of a HT setup on their website using the wall mounted speakers.

[squeegy200]

I have written a Exel table where you can enter your room and speaker data. It will calculate the needed distances in order to keep an odd ratio so that you can place your dipole planar speaker correctly. Doing so with greatly improve transparency and bass responce. Klick here to download the small exel file.

http://www.apogeeclub.de/audioreview/ratio.xls

Florian,

The worksheet does not work anymore.

I've been experimenting with the Cardas positioning of my magnaplanars.

[hermanv]

Yeah I know I'm late to the thread. I agree completely about back wave control.

I bought some natural fiber carpet underlayment at a local wool carpet store. If I remember about 40% wool, 20% camel hair and jute. It was about 7/16 thick and reasonably priced. I cut it into 2 panels 6 x 8 feet and hung them behind my Martin Logans so the panels wrapped around the room corners (a narrow 11.5ft room) by about 1.5 feet and went floor to ceiling. Speakers were out from the rear wall about a yard. It all worked great.
http://www.greenfloors.com/HP_CP-Under_Index.htm

Sound Lab sells a commercial absorber panel, it's about 6 feet tall and 2 feet wide with stands. I don't know the price, but since it's Sound Labs it's probably not cheap.
http://www.soundlab-speakers.com/accessories.htm

Also I just found these people 2' x 4' x 4" at $47 each, includes mounting hardware.
http://www.atsacoustics.com/cat--ATS...nels--100.html

[E-Stat]

Sound Lab sells a commercial absorber panel, it's about 6 feet tall and 2 feet wide with stands. I don't know the price, but since it's Sound Labs it's probably not cheap.

No they're not. List is $1170 / pair for the Sallies.

For quite a bit less, however, I have been very successful by making a dozen DIY bass traps. They helped me achieve a remarkably flat response in the bottom three octaves. I also use some absorptive panels directly behind the speakers and placed fake ficus plants at the first reflection points.

rw

[hermanv]

No they're not. List is $1170 / pair for the Sallies.

rw

Heck, that'll buy a speaker cable for one speaker

[BOXMAN]

I have written a Exel table where you can enter your room and speaker data. It will calculate the needed distances in order to keep an odd ratio so that you can place your dipole planar speaker correctly. Doing so with greatly improve transparency and bass responce. Klick here to download the small exel file.

http://www.apogeeclub.de/audioreview/ratio.xls

I am late to the thread... but interested in this spreadsheet. As someone already pointed out, it no longer works. Any idea where another one of these spreadsheets can be found??

Thanks
Boxman

[Florian]

The main clue is to have an odd ratio between the side and backwalls. I can whip up another spreadsheet, but it will take some time since i am quite busy. Just make sure to have an odd ratio.

Cheers


Flo

[hermanv]

Dipole speaker positioning has two issues, one is the back wave sum/difference for clarity, the second is to match room standing waves for good bass.

I found the Cardas placement guide very good for minimal bass nodes.
http://www.cardas.com/content.php?ar...ing=Room+Setup Conveniently this also tends to place the speakers a good distance from the back wall. I set mine at the Cardas distance and then worked with absorptive panels to get the needed clarity. It's a pain, but worth the effort since most dipoles seem to have great clarity easily destroyed by placement problems.

If you are used to conventional speakers, you might not even be aware of the missing clarity. Use the Cardas guide, then get some down quilts and "T" pins. experiment with hanging the absorptive material at various positions behind the speakers with various folding for width and thickness. If you find a combination you like next experiment a little with toe in. Planars on the whole seem to do best with less toe in than you might be used to.

It's possible that more than one iteration might be needed for the absolute best answer.

Now buy or make a permanent panels to replace the down comforter (I find that thicker is usually better) and enjoy the music.

[undermench]

good evening i have owned a pair of mag I D 's since around 1975 purchased from david beatty hi fi in kansas city mo. ok so big deal they have provided excellent sound i I have them paced 18 inches from the back wall and the same distance from the side wall. I get a nice level of bass response. the side walls are basically not interrupted by any furniture. i drive my speakers with a pair of modified dynaco pas 70 in the final stage are a kt-66 set of matched tubes. the grids are baised hot. they approx develop about 100 rms per chanel into a four ohm load. the amos are strapped so each one acts as a mon amp.. I believe that maggies work best with tubes. why. if i am correct what most people are not aware of is that maggies are not just a purely resistive load they also present a capactive load also. a transistor amp in some cases can not handled a capacitive load. they some time suffer from severe oscillationswith very bad results reduced power out, poor respone and in some cases they just burn up. the rest of my system is a audo research sp-7 with a thorens turntable with a straight line tracking tone arm a rae rabco sl8-e old equippment but still very esotewric. one more thing ya i know tube amps run about 1 to 3 % distortion but the human ear really cant detect this thanks for reading this UNDERMENCH