Room Acoustics treatment for electrostatics

[bikerabbi]

It will be interesting to hear the back wall effect of my log home. Both the inner and outer shape of the walls are "D" shaped 10" logs. There may just be enough dispersion effect in the wall to give a really nice effect. It pretty much equals horizontally the 30 degree shape of the ML 30 degree vertical dispersion. Next week I hope to have it set up. Stay tuned...

 

[candyman]

I have a couple RT Mini-trap HF panels on order that are scheduled to arrive Friday. I ordered the panels, as the first step in acoustically treating my AV room, based upon Jonathan's writeup and measurements several years ago regarding the back wave effects of dipole ESL speakers. The HF panels will be placed behind my reQuests and I hope the benefits are as noticeable as when I switched from a Yammy receiver to a power amp/pre-pro.

Rob

 

[RUR]

I have a couple RT Mini-trap HF panels on order that are scheduled to arrive Friday. I ordered the panels, as the first step in acoustically treating my AV room, based upon Jonathan's writeup and measurements several years ago regarding the back wave effects of dipole ESL speakers. The HF panels will be placed behind my reQuests and I hope the benefits are as noticeable as when I switched from a Yammy receiver to a power amp/pre-pro.

Rob

Excellent! You should hear an immediate improvement in HF clarity, esp. things like high piano notes, close-mic'ed vocals and such. Move them around until you get the best improvement and, just for fun, try using them at the first reflection point, as well.

Looking forward to your findings and welcome to the forum.:music:

/Ken

 

[Gordon Gray]

Ats

Peter,

Absent DIY, ATS panels are the best value from a price / performance perspective.

GG

 

[Rich]

The HF panels will be placed behind my reQuests and I hope the benefits are as noticeable as when I switched from a Yammy receiver to a power amp/pre-pro.

Rob

Don't forget to turn it up a little louder than you normally listen. Dampening the back wave of the speaker will reduce overall volume levels at the listening position by about 6 db, if I recall correctly.

I expect you will notice immediate improvements in clarity, localization of instruments, and overall coherence.

 

[candyman]

Don't forget to turn it up a little louder than you normally listen. Dampening the back wave of the speaker will reduce overall volume levels at the listening position by about 6 db, if I recall correctly.

I expect you will notice immediate improvements in clarity, localization of instruments, and overall coherence.

Rich, thank you for the tip. I'm going to start with 2 channel operation for A-B comparison but you've reminded me that I'll need to recalibrate, especially for 5 channel.

Rob

 

[rasmaudio]

Damping, diffusing and distance

Hi Peter, the ‘magic’ of dipole is actually more of a side-effect of not wanting to have uneven dampening of the diaphragm with some form of rear enclosure.

So the choice of dipole is somewhat of a trade-off. To gain responsiveness from low-dampening of the ESL vs lose out to comb filtering and rear-wave cancelations at lower frequencies.

The challenge that a dipole presents in terms of room placement and listener positioning is a lot larger than for monopoles, as the delayed and out of phase rear wave produces a time-delayed, phase shifted signal that has to be ‘blended’ as it were into the actual information arriving from the front of the panel.

This ‘blending’ is never smooth, which is why there is comb-filtering clearly visible when looking at a frequency response plot.

The dipole effect is literally the same as taking two monopole speakers, spacing one of them away from the other by 6 or more feet and feeding them the same signal, except out of phase. Generally, not a recommended 2ch ‘purist’ type of arrangement

Therefore, we come to the realization that managing that rear energy is something we should pay attention to.

Not that everyone *should* dampen the rear-wave, it’s just you need to think about how the ricochet and delay of that out-of-phase signal is going to affect the soundstage in *your* room.

Dipoles speakers do require damping of the back wave but also diffusion and the distance from the front wall should be large to minimize comb filtering. I place my Martin Logan Sumitts 7' from the front wall and with the angle of the Magneplanar Tympani bass panels they are 9' from the front wall. I also use the long wall for all the front speakers as this gives a very wide soundstage with a depth of field that is awesome. See my post on acoustics. (rasmaudio)

 

[hifiaudio2]

Thanks, Greg. Jonfo and I, among others, have been preaching this for years. Glad it worked for you. Ultimately, I suppose some of it is subjective. Some people like the "ambiance" of interfering reflections because that is what they have grown accustomed to or because that is "supposed" to be one of the "benefits" of ESL speakers. They simply don't realize, in my opinion, the huge gains in clarity, imaging, and soundstaging that come with minimizing obstructive reflections and listening only to the front wave of the speaker (which is the way the signal was intended to be transmitted to your ears). Unless you can increase the time-delay of rear wave reflections by having a large enough room, and having the speakers far enough from the front wall, then absorption behind ESL's really is the way to go.

Rich - Is there an accepted "minimum" distance to have the panel from the front wall where absorption becomes less important? My room is 17W x 27L x 9H and currently I have my CLX pair about 3ft from the front wall. I want to move it further out but I cant move my seating back due to a bar being in the room so I am as far out as I can go for now. I want to remove the bar and sell it and that opens up some opportunities. In fact, once I do that, I will probably move my seating back from 12ft from the front wall to 18ft, as that is the 1/3 of the room length "sweet spot" that I keep reading about for least number of bass modes.

So how far out into the room should the CLX be put to assume absorption behind them might not be needed to cancel the wave?

 

[twich54]

So how far out into the room should the CLX be put to assume absorption behind them might not be needed to cancel the wave?

While I'm sure Rich and some of the other acoustic experts will chime in here's my take......... first off the size of your room is superb, second, get rid of the stupid bar ASAP. For the life of me I can't understand anyone having a top flite pair of speakers like the CLX's and not giving them their proper set up.

In so far as your question.........6-8' with corner bass traps (ideally floor to ceiling) and maybe some diffussion along the wall should work nicely.

 

[hifiaudio2]

OK cool thanks. Yeah I have wanted the bar out for a long time...just havent done it yet. I didnt put it in, was here when i moved in, and I am not really sure what they did to install it. Its a basement slab floor and the thing certainly doesnt move.

I do have GIK tri traps from floor to ceiling so once I can move the CLX's out sounds like i should get some nice improvement.

 

[|Tch0rT|]

My room is 12.5' W, 20' L, x 7' H. The panels are about 3' away from the wall behind them and at least 3' from the side walls. The EM ESL's are about 5' apart and I sit about 7.5' away. What kind of treatment should I be looking at? Right now I'm thinking of buying this kit:
http://www.amazon.com/Auralex-Studiofoam-Designer-Charcoal-Gray/dp/B0002F78UI/ref=pd_cp_MI_2

My ideas are at least treating the 1st reflection point and experiment with the 2nd refection.

Any ideas for a room treatment noob like myself?

 

[churchill]

My room is 12.5' W, 20' L, x 7' H. The panels are about 3' away from the wall behind them and at least 3' from the side walls. The EM ESL's are about 5' apart and I sit about 7.5' away. What kind of treatment should I be looking at? Any ideas for a room treatment noob like myself?

Ryan, here are a couple of pics of my room treatments, I'm using a combination of ATS sound panels and GIK and ASC bass traps.

 

[invenio]

I definitely think that some minor dampening brings out the best sound with dipole speakers. I also think that correct placement with ML's are so critical that they can not be over-emphasized. Electrostatic speakers are wonderful but very sensitive to placement. It should be crime to put them right up against a wall! I give mine over 5 feet to "breath". You can check out more pics of my setup at:

http://www.blu-ray.com/community/gallery.php?member=invenio

 

[adanny]

This venerable thread has been a big help.

I have used it to design the room treatments in my multipurpose room. Would love your feedback.

Room Dimensions and key facts
23' x 39' by 12' (w x l x h). Height is actually 9 feet of flat wall, followed by 4’ angled at 45 degrees, resulting in average height of ~12’

Ceiling has an 8’ attic, with lots of thick insulation between attic and this room.

Speakers (7): Summit mains, Stage center, Script and Script I’s on sides; Need to add 2-4 subwoofers.

Gist of my design is
a) floor to ceiling Bass traps in 3 out of 4 corners
b) floor to ceiling absorption panels behind the summits, wood panelling and diffuors between the Summits (although there will also be a plasma which aint great for reflections but it is what it is)
c) ~10-12 additional 2 x 4 x 2" sound absorbers on the left, right walls.
d) potentially a "cloud" absorber on the ceiling although Im wondering if that is now overkill

I have lots of photos and designh sketches but the forum file size did not allow them to be uploaded regardless of how much i whittled them down. They are as small as 68 kb but still not uploading