Dipole speaker positioning

Discussion in 'Hi-Fi and General Audio' started by Dom_, Oct 6, 2007.

  1. Dom_

    Dom_ --->

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    After a few hours of playing around i think i have my esl63's in a good position now.
    However i see plenty of guides out there for normal speakers but almost none for dipoles. Is there any general rule or guide around?
    I know it is all room dependant and furniture etc etc but would like a rough idea.
     
    Dom_, Oct 6, 2007
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  2. Dom_

    ADPully

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    Ive always found my dipole speakers have worked better paralell with the long wall - around 1/3 out and well spaced apart
     
    ADPully, Oct 6, 2007
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  3. Dom_

    Parkandbike

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    I believe Peter Walkers' guidance was:
    - Firing down the long dimension of the room (presumably for the lowest base standing wave).
    - Placed about 1/3 of the way down the room (presumably to minimise the impact of the back wave being reflected from the wall behind)
    - not too critical about distance from the side wall (presumably because the two wave fronts cancel to the sides

    These guidelines seem to work pretty well. I've found 3-4 ft behind the ESLs is fine (although this does not meet the 1/3 criterion) and that they can be paced wider apart than you might think without getting a hole-in-the-middle effect. A slight toe-in also seems to help.

    Noel Keywood used to advocate sound aborbing materials behind the speakers
     
    Parkandbike, Oct 6, 2007
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  4. Dom_

    3DSonics away working hard on "it"

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    Hi,

    Some notes, ELS-63's should ideally be raised enough to have the the center at around earhight, using a very rigid stand and Alastair Robertson-Aikman's trick of hanging a large round pillow (today I'd probably use a 20 - 30" square around 15" - 20" behind the speakers center can help a lot to deal with the excessive room reverb and allow a closer placement to walls than normally possible.

    Further, if you do not use seperate subwoofers optimising the speaker position for low frequency performance is difficult. A dipole (or velocity transducer) works best close to walls at low frequencies and also the low frequency radiation is directional.

    However Quads should be quite far from walls for best midrange and spatial behaviour, with the area behind the speakers acting as diffuser/absorber for the widest possible bandwidth.

    The best choice in my view and experience is to use the Quads on stands a fair bit into the room optimised for midrange purity and spatial redition and hand over below 150Hz actively to a dipole (or unipol) subwoofer pair (example, the Alex Ridthaler RiPol Kit from http://www.lautsprechershop.de/english/index_hifi.htm) set up to optimise the low frequencies.

    Ciao T
     
    3DSonics, Oct 7, 2007
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  5. Dom_

    Dom_ --->

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    Thanks for the respones.
    I currently have them on stands so the centre is ear height. But instead of super rigid i just used a couple of lak tables cut to the right size.

    Placement is not a problem as i have no wife. So they are currently about a third out as Parkandbike suggested and this has done wonders.
    I also placed a few of my lp cubes on the wall behind the speakers (full of lps) which seemed to do nothing, so i might get some foam.

    As for subwoofers, would i have to pass the signal into the sub and then on to the speakers to cut them off at 150Hz?
     
    Dom_, Oct 7, 2007
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  6. Dom_

    Parkandbike

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    Tilting them back has also been suggested as an alternative to raising them off the ground to improve treble- although this would presumably give a variable effect with listenting distance.

    The Gradient SW63 which was designed to go withthe 63s solves both height and LF extension issues. The cross-over is around 100Hz and it is a dipole design. Many feel that the cross-over spoils the mid range clarity of the Quads, but on one of the enthusiast web sites there is a simple mod, which I have found very effective. The use of these subs also addresses the concern some people have about the how loud the Quads can go, since they no longer have to handle the signal below 100hz

    Incidentally there is a pair of SW63s currently available on EBay (nothing to do with me)
     
    Parkandbike, Oct 7, 2007
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  7. Dom_

    3DSonics away working hard on "it"

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    Hi,

    Try making the LP's "untidy", so that blocks of different LP's arepulled forward, approximating a diffusor like this:

    [​IMG]

    Not neccesarily. You can build/have build a simple passive line-level highpass for the Amp driving the Quads, very much like it was done for the big multiamped Infinity speakers. This has an absolutely minimal impact on transparency.

    If you know the input impedance of your main amplifier the highpass is easily calculated. You can even still use an active subwoofer with speaker level feed from an integrated Amplifier, with a specific trick.

    To not bore people with endless debates of DIY methodolgies etc., maybe PM me or set up a thread in DIY if you need more?

    Ciao T
     
    3DSonics, Oct 7, 2007
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  8. Dom_

    3DSonics away working hard on "it"

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    Hi,

    BTW, the Gradient Subs are a great choice, if you can afford/snag them.

    There was also an extensive DIY sub for quads article in HiFi World some years ago (may be as much as ten), I seem to remmeber copies of this floating around on the net, had a look, these might help:



    And the HiFi World DIY Article:

    http://audiodesignguide.com/doc/Active_dipole_subwoofer_p1.jpg

    http://audiodesignguide.com/doc/Active_dipole_subwoofer_p2.jpg

    http://audiodesignguide.com/doc/Active_dipole_subwoofer_p3.jpg

    http://audiodesignguide.com/doc/Active_dipole_subwoofer_p4.jpg

    It is also worth reading the HiFi World Article on adapting the Celestion SL-6000 Dipole Sub for Quads.

    Ciao T
     
    3DSonics, Oct 7, 2007
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  9. Dom_

    mr cat Member of the month

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    try www.avtalk.co.uk/forum

    they're an AV site - full of experts on there...no offence toi anyone on here!
     
    mr cat, Oct 7, 2007
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  10. Dom_

    Dom_ --->

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    Thanks for the info again guys. Plenty to look at and think about.
    The subwoofer option may have to wait a bit as i have spent too much on the hifi lately. Unless i go DIY....
    If that happens i will post in the diy thread and get some ideas going.
     
    Dom_, Oct 7, 2007
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  11. Dom_

    dreftar

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    Thanks for raising this issue. The placement of my Quad ESL63s were as much to do with WAF than anything else, but since I placed them they have crept out from the rear walls and moved closer to the side walls. That was interesting the post talking about a round pillow behind them. Ill give that a go next shopping day when She WMBO is out! Incidentally I use a Behringer Truth Sub - I dont use the passthrough, it is connected to the other output of my preamp. I have it set to a very low volume and I find it very useful on some recordings as it gives some weight and depth to the low end.
     
    dreftar, Oct 7, 2007
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  12. Dom_

    pixies a menace to society

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    Quad ESL placement is critical to the sound quality - they will never sound bad but can sound stunning if positioned correctly. The 1/3 long room placement is a starting guide but not entirely practical for most peoples living rooms. I have a large listening room and can do this but after experimentation they sounded better width ways across the room in a near field setup with a relatively wide placement with a fair amount of toe in towards the listening position. Peter walker himself suggested that only 90cm is needed behind and this is actually the distance that gives the right balance of bass warmth in my room. Quad's own development and listening rooms quite smaller but their setup is almost identical to mine - the rearward bass energy can destructively interfere and actually reduce the measured bass response if too close though. The 1/3 setup did not have enough bass output. One of the most important considerations is the treble. The ESL's were designed to use the rearward reflected treble energy to augment the forward treble output, and as such heavy damping behind the speakers is not required as it dulls the treble and makes directionality even worse. This increased dispersion is required to open up the soundstage as the speakers should be a fair way apart. The treble of the 63's is less elevated than the newer 988 and 2805 so needs even more care here.
    This wider dispersion also means that stands are not needed. Raising the speakers causes a hollowing of the midrange due to the loss of interaction with the floor. Why would anyone want to spoil the midrange of the 63's? The newer electrostatics were purposely made with bases that would not match even the Quad made bases for this reason(these stands were only made due to pressure from the North American market.) Quads answer of course was to tilt the speakers back on their own bases to address midrange and treble directionality. If you're not happy with the bass response then the solution is only to move the speakers forwards or backwards slightly from the rear wall. Apart from that, as they are non resonance speakers, placement and room/bass interactions are not overly important.
    One improvement that can be made (apart from stripping them down) is to brace the rather flexible frame to the back wall with wooden struts. This will add more punch if required. The ridgedness of the newer ESL's is one of the improvements over the older 63's - the basic design apart from that is very similar.
     
    Last edited by a moderator: Oct 18, 2007
    pixies, Oct 18, 2007
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