Absorption or diffusion panels behind ESLs?

[RTR001]

Hey all, I'm hoping someone on here may have some experience with electrostatic speakers and difficult placement requiring the use of acoustic panels.

 

I've purchased a pair of Martin Logan ESLs for my lounge room and I went in with my eyes open regarding difficult placement etc of this type of speaker. My situation is that ideally I need them to sit a little further back than the minimal recommended 2' from rear and side walls. They sound great where they are at the moment but having them so far forward is not aesthetically pleasing in our main living area (and the Mrs needs to be as chuffed as I am) so I want to move them back into more of a 'traditional' speaker placement.

 

Does anyone have any experience running these closer to the walls? I'm assuming absorption panels behind /beside will help but will it also reduce the sound stage/volume? Would diffusion panels be better behind them? My ideal placement would have one speaker ~1' from the front and side wall, while the other is open on the sides but would still be ~1' from the front wall.

 

Really appreciate any advice/wisdom

[Zaphod Beeblebrox]

Absorption panels are the way to go. Apparent SPLs will fall a little, but imaging will improve significantly. Diffusion systems will cause poor(er) imaging. Toeing-in the speakers may help somewhat. 

[RTR001]

Thanks @Zaphod Beeblebrox! They're currently toed-in slightly which helped find the sweet spot where they are at the moment. Looks like my weekend will be spent experimenting with some absorption materials which was always the plan but it's good to rule out diffusion as an option.

 

 

[aechmea]

My planars are well out into the room and I have had no experience with a close-to-the-wall situation, however ...

 

I have used, at one time, large amounts (3 full sheets of 100mm semi-rigid fibreglass) of absorption behind the speakers on the front wall.  The imaging becomes very focused and pin-point accurate.  However the trade-off is that the soundstage width narrows back towards the centre.

 

These days I have some absorption; about 1/4 of what I had before and a tall strip of diffusion panels on each side of the front wall placed where part of the backwave reflects directly at the chair.  The diffusion went a long way toward fixing a L vs R imbalance.

 

My backwave is roughly directed into tube traps in the corners, so I think that there is a bit of scattering from the tubes and from the side and front walls.

 

In general you can expect to hear from posters that you shouldn't absorb behind the planars because that "kills" the life and expansiveness that is the hallmark of planars.  I don't quite buy into that, and I am happy with a bit of both absorption and diffusion.  It's all a matter of preference.

 

[Edit:  Forget traditional side-wall absorption.  It's not needed for planars which have a figure 8 pattern ie. nothing/nothing much out to the side.]

Edited March 20, 2018 by aechmea

[Zaphod Beeblebrox]

15 minutes ago, RTR001 said:

Thanks @Zaphod Beeblebrox! They're currently toed-in slightly which helped find the sweet spot where they are at the moment. Looks like my weekend will be spent experimenting with some absorption materials which was always the plan but it's good to rule out diffusion as an option.

 

 

Every time I've set-up ESLs, I've had to spend a very considerable amount of time to get it right. Once done, however, the results can be most rewarding. 

[davewantsmoore]

1 hour ago, RTR001 said:

~1'

I assume this is "1 foot" ... and that you mean from the wall the diaphragm.

 

If so that's very close.

[Mr 57]

A post I made some time ago, absorption like the other guys have suggested, is the answer.

Even our mighty Peter Walker suggested a couple of wool blankets behind the ESL to hear the advantage.

[RTR001]

13 minutes ago, davewantsmoore said:

I assume this is "1 foot" ... and that you mean from the wall the diaphragm.

 

If so that's very close.

Yeah 1 foot from the side. The bass driver in the bottom would see the panel itself still close on 2 feet off the wall. I can still bring them forward more but in an ideal world that is where they'd sit. Unfortunately the side wall is the biggest issue. Potentially I could put a absorption panel just on the side and bring them forward some. I'll give it a try.

 

30 minutes ago, aechmea said:

My planars are well out into the room and I have had no experience with a close-to-the-wall situation, however ...

 

I have used, at one time, large amounts (3 full sheets of 100mm semi-rigid fibreglass) of absorption behind the speakers on the front wall.  The imaging becomes very focused and pin-point accurate.  However the trade-off is that the soundstage width narrows back towards the centre.

 

These days I have some absorption; about 1/4 of what I had before and a tall strip of diffusion panels on each side of the front wall placed where part of the backwave reflects directly at the chair.  The diffusion went a long way toward fixing a L vs R imbalance.

 

My backwave is roughly directed into tube traps in the corners, so I think that there is a bit of scattering from the tubes and from the side and front walls.

 

In general you can expect to hear from posters that you shouldn't absorb behind the planars because that "kills" the life and expansiveness that is the hallmark of planars.  I don't quite buy into that, and I am happy with a bit of both absorption and diffusion.  It's all a matter of preference.

 

[Edit:  Forget traditional side-wall absorption.  It's not needed for planars which have a figure 8 pattern ie. nothing/nothing much out to the side.]

Thanks aechmea, thats some great info. 

 

13 minutes ago, Mr 57 said:

A post I made some time ago, absorption like the other guys have suggested, is the answer.

Even our mighty Peter Walker suggested a couple of wool blankets behind the ESL to hear the advantage.

Thanks Mr 57, I'll have a read through. I didn't come across that one in my googling. I did find an interesting youtube video on building some absorption panels from op-shop towels in a timber frame which I thought I might try as a starting point to be able to easily position and listen

Edited March 20, 2018 by RTR001

[JSmith]

17 minutes ago, aechmea said:

I don't quite buy into that

Consider a diaphragmatic absorber;

 

https://www.acousticfields.com/product/acda-10-activated-carbon-diaphragmatic-absorber/

 

JSmith 

[blybo]

Even 2 foot is far from ideal, try 1 metre + to get full range response and clarity from any dipole speaker. I'm no acoustical expert (far from it) but I'm told it's to do with the figure 8 radiation pattern. Thankfully side wall reflections are not as important in these designs and at least you have a sub built in.

 

The closer you go to the wall the more you will loose response in the bottom end of what the panel is producing and more from the sub. If you bought new and told the salesman about your positioning issues, I'd question whether they have done the right thing by you.

 

I have my dipole Spatials 1 metre from the wall (I'd like them further out but don't have room) and my wife ******* about it but they stay. I do have them on sliders so I can put up against the wall when cleaning or kids are playing in the room. I've got self adhesive dots on the floor where the sliders should rest so easy to put back in their spot.

Edited March 20, 2018 by blybo

[blybo]

... from my understanding, if you can change the crossover between panel and sub, I'd be making it as high as possible @ 1 foot from the wall.

[BruceS]

I have heavy curtains behind my electrostats with the speakers just in front of the curtain (& as close to the side walls as is possible) and that works well.

In correspondence with Roger West of SoundLab he agreed that this was very good.

Will say that, at least for my electrostats, it is very important to keep moving them until everything locks into place.

You will easily hear it when it happens!

Sometimes it only takes a tiny movement for everything to become perfect!

Good luck for your electrostats.

Enjoy the listening.

Bruce

[frankn]

18 hours ago, Mr 57 said:

A post I made some time ago, absorption like the other guys have suggested, is the answer.

Even our mighty Peter Walker suggested a couple of wool blankets behind the ESL to hear the advantage.

The original comment by PW was in response to Ivor Humphreys question about using a pair of 63’s in a UK spare bedroom.  Spare Bedrooms in UK houses were/are small, typically 12ft x 12ft or less.

Attached is a copy of the original letter

 

Edited March 20, 2018 by frankn
Missed a bit

[Wimbo]

I used to have my ESL 63's 2 metres from the rear wall and 2 and a half metres apart from the inside edges with Archici stands on bricks. Rear wall was brick with a double window in the middle and heavy drapes.The soundstage detail was amazing. You could almost walk into it. I use to stand in the same Parallel as the speakers and look into it.  This was with a mid 80's LP12/Ittok , DNM series 3 Twin pre and modified Marantz MA6's.

[Mr 57]

@frankn absolutely correct sir, I see someone else has indulged in KK’s book....only the diehards lol.

Great read, kneeling at the temple of Quad 

[frankn]

It's nice to share a few pleasures eh...

 

Its possible to need both absorption and diffusion depending on the room and the speakers.  ESL's can benefit from both.     

[RTR001]

Thanks for all the input guys! Once she who shall be obeyed finished watching Married at First Sight (I can't possibly think of a greater use of my new toys...) I got down to some tinkering.

 

I decided to start from square one and relocated them to exactly where I wanted them. I moved the left speakers closer to the side wall into my ideal spot but I also moved them as far forward as I could without them being too intrusive into the space. The panels are now 2.5 feet from the front wall, 1 foot from the left side wall and 9 feet apart. After a bit of poking and prodding I felt they were sounding pretty good. I used a tape measure to check distances, toe in etc so I have a reference for further tweaking later.

 

I then started experimenting with some blankets pinned behind them as suggested above. It didn't take much to start noticing a difference so some basic absorption panels are definitely in order. I plan to experiment with additional layers of blankets tonight or tomorrow before considering the final solution.

 

On a bit of a side note, I am finding them a little bright on some tracks, particularly some of the guitar highs on the Pink Floyd's Animals LP for example. I suspect this is probably just a more accurate reproduction that I am used to getting with my old towers.

 

All in all it was sounding better by the time I called it a night.

Edited March 20, 2018 by RTR001

[blybo]

5 minutes ago, RTR001 said:

The panels are now 2.5 feet from the front wall, 1 foot from the left side wall and 9 feet apart. After a bit of poking and prodding I felt they were sounding pretty good. I used a tape measure to check distances, toe in etc so I have a reference for further tweaking later.

Is that measured from the front of the panel or rear of sub enclosure? If rear then that's a great overall distance out into the room. Well done.

 

If SWMBO decrees that the speakers must be close to the wall day to day, marking out your optimum location and moving them is still an option. It looks like the esl's have a threaded floor spike. The sliders I mentioned earlier are the "Threaded Stud Glider" halfway down this page http://herbiesaudiolab.net/spkrfeet.htm

just choose your thread diameter. I took my original spikes to Bunnings and inserted them in the thread measuring guide in the "fasteners" isle to find the right size. I got on to them from other members on this site who have used them successfully. Lots of other interesting decoupling devices on that site too .

I'm sure there are other options too, but these look original & glide effortlessly on my timber floors whereas I previously had to "walk" my speakers back and forth on the rubber feet they also come with. Thankfully my speakers now spend 90% of their time in my preferred position, but it's only a 20 sec job to get them out of the way when necessary.

 

[JSmith]

2 hours ago, blybo said:

If SWMBO decrees

From what I read he was just waiting for his wife to finish watching a show?  

 

@RTR001 is there any issue with placing your speakers in your home where you would like them?

2 hours ago, RTR001 said:

All in all it was sounding better by the time I called it a night.

Good to hear.

 

JSmith 

[RTR001]

3 hours ago, blybo said:

Is that measured from the front of the panel or rear of sub enclosure? If rear then that's a great overall distance out into the room. Well done.

 

If SWMBO decrees that the speakers must be close to the wall day to day, marking out your optimum location and moving them is still an option. It looks like the esl's have a threaded floor spike. The sliders I mentioned earlier are the "Threaded Stud Glider" halfway down this page http://herbiesaudiolab.net/spkrfeet.htm

 

Unfortunately no, it's 2.5 feet from the closet part of the panel itself. Conveniently, these were supplied with very similar feet to what you've linked to above. I'm on carpet so was actually planning on fitting spikes. I might reevaluate...

 

1 hour ago, JSmith said:

From what I read he was just waiting for his wife to finish watching a show?  

 

@RTR001 is there any issue with placing your speakers in your home where you would like them?

Good to hear.

 

JSmith 

It's a tricky space to explain. The lounge room is an L shape but open plan joining with the living room which is also an L shape. Unfortunately there is a double sliding door smack in the middle of the two spaces leading into the main entrance and corridor. The right speaker sits next to the door so moving them forward puts a speaker smack in the middle of everything. It's not impossible, it's just impractical. 

 

Here is a terrible attempt at a quick diagram. All black lines are solid walls. Speakers are green. Sliding doors are red. Windows at the front are purple. Kitchen is the semi enclosed space at the top/middle.

| --------------|-------- |

|         ____|          |

|                           |

|______ __ |____| |

 

I knew when I bought them I'd be making some compromises in terms of placement and ultimate sound quality in my space. They already sound better than my old towers, it's just a question of how much more I can get out of them without being too intrusive. I think I'm on the right track now though thanks to everyone's help.

Edited March 21, 2018 by RTR001

[RTR001]

Righto, probably taboo not to spend a fortune on these things but in a few hours tonight I knocked up some basic absorption panels to wall mount behind the towers. Simple pine frame, 7 layers of thick cotton towels from the op-shop and a fabric cover. Roughly $30 in total. Gotta say, they work a treat. Imaging and clarity has greatly improved and the speakers haven't moved from their sub-optimal position. Happy days!

 

[Mr 57]

Well done, great satisfaction from finding a solution. Never feel you have to throw lots of money at it. It’s a journey of discovery, and we all learn something. Only by trying and sharing these ideas do we progress in our hobby.

Well done Sir ! Now time to enjoy, until another tweak twitch itches ...

[Primare Knob]

Having some Martin Logan's myself I did find the following.

The speakers like to be placed wide apart.

The back wall has more impact than the side walls.

They work best in a symmetrical setup and room

3 ft from the back wall is a minimum, the closer to the wall, I would look into absorption first, the further from the wall I would start with diffusion.

The ML formula for listen position compared to speaker width placement is a rather important one. Speaker width distance x 1.25 as a minimum. I would Honor this and compromise on back wall distance than the other way around.

Tow in, and vertical angle alignment can also help improve things, as they aren't completely uniform over the whole panel area.

They aren't difficult speakers to get a good result, they are more tricky to produce a great sound, where the room and shape will start to play a big role.

[Primare Knob]

I would experiment with placing absorbent panels on the left wall, and the wall opposite from your right speaker in an attempt to compensate for the asymmetrical room.