Live End / Dead End room treatment

[JkSpinner]

I have been doing a lot of reading and watching many videos of setting up 2 channel Hi Fi and HT rooms.  From all of this google research, I get the impression that traditionally, the approach is the make the front end of the room the dead end using absorption, and the back end of the room the live end, using diffusion.  I have also see the LE/DE approach dividing the room into three zones

Zone 1 = front wall to speakers

Zone 2 = Speakers to listening position

Zone 3 = Listening position to rear wall. 
 

From all this reading I believe that most recommend dead end between the front wall and listening position (zone 1 and 2) using absorption thus allowing you to hear the speakers as accurately as you can, , and live end behind the listening position (zone 3) often using diffusion.  However I see a lot of people suggesting Diffusion in Zone one and or 2, helping to widen the soundstage etc, creating a more lovely sound.  I watched a video where PS Audio suggested live end in Zone 1 and 2 and all absorption in Zone 3.  PS Audio suggested this resulted in lively sound stage, and very little reflection from the rear.  
I also see that the many of the solutions from Acoustic Fields in the US includes Diffusion accounts the front wall, and mostly absorption on the side walls.

 

i can kind of see the merits in both.  What do most people from this forum do?

[nil]

Hey Jk,

get yourself a couple of 50mm thick Autex panels 2.4mx1.2m for absorption.  ... get a thick underlay for any rugs.  and start trying things out.

Differences will become apparent quickly. You'll be moving the speakers around and shifting furniture too. It's no small task to get it right. But well worth the effort.

 

If you're serious - then hire a pro to get it done properly, quickly. It'll save years of mucking about.

 

 Personally, I'm still in the mucking-about phase.

 

 

[JkSpinner]

Thanks Nil, I posted a separate thread on thoughts or different brands of panels.  I ended up with 6 primacoustic panels for, at this stage, the rear wall, and one each beside the listening position.  
so for this thread, I have chosen the rear of the room to be the dead end.  And I also bought some Hybrid panels, Diffusion type panels that I am currently using in the first reflection point.  At this stage, they are moveable, so will be playing around a bit, moving them around.  At this stage, I think I might end up with more diffusion behind the speakers as I am liking the effect or SQ at the moment

[nil]

That sort of room-set-up is what I have (as decided by architecture - not acoustic experimentation). 

 

A wall of bookcases behind the speakers (diffusion) and a wall of extra heavy curtains at the other end for absorption.

Plus, some not-yet-fixed absorption panels that have stayed in the first reflection point for years now.

A thick rug underlay made a huge difference for my space, and was inexpensive too (thank you Pottery Barn/West Elm)

 

Of course, moving your speakers around just one or two feet makes a big difference to results.

Although it can become complex (room nodes etc.), the basics are easily understood, and you'll definitely end up with an improved listening experience from your efforts.

 

For my next step, I am considering digital EQ (dirac possibly). That sort of approach seems to be getting positive results for SNAers who dabble in that sort of thing.

 

Please let all of us know where you get to next.

 

Thanks for sharing

 

 

 

[JkSpinner]

On 25/8/2024 at 10:14 AM, nil said:

Of course, moving your speakers around just one or two feet makes a big difference to results

Been moving my speakers around, moved them out a fair way, and slowly moving them back again, found that I was lacking in bass.  Probably something to do with a 4m glass door on one side and a 2.5m opening to the entrance on the other = a very leaky room.  I may look at a subwoofer or two, (would not mind trying some 15” Woofer JBL’s either, not sure it would add much though) or create a temp wall in front of the window, or something. + adding 8n diffusion panels at 1st reflection point kind of replicates a wall - sort of.

the six panels seem to do the trick with the midrange and high end, and decay time I think, however adding the diffusion, seemed to put it all back again. - when measured that is.  It sounds better.  But that is probably another discussion.  I will continue to move things around, and take measurements to see what the effect is each time, might be a long process

[Craigandkim]

2 hours ago, JkSpinner said:

I may look at a subwoofer or two

If you want bass, try two or more strategically placed subs they will make a world of difference when integrated with the mains.

[almikel]

Hi JkS,

 

You should edit the title of your thread as it has a typo - Line not Live

 

Toole, Olive and Geddes take different approaches for achieving great "in room" sound compared to the LE/DE approach - but these 3 people recommend starting with a speaker that has a smooth on axis and off axis response - sometimes called Controlled Directivity speakers.

 

Toole and Olive, when working for the Harmon Group, published multiple papers based on their research on what makes a "good sounding" speaker based on many listeners in controlled environments.

 

I'm not suggesting you swap your speakers out!

 

But treatment placement will likely change depending on how well your speakers' "off axis" response matches their "on axis" response.

 

Taking Toole's approach, assuming a speaker with a smooth "off axis" response - Toole recommends not using absorption at lateral 1st reflection points, as those reflections assist with developing a sense of space in the room (because the 1st lateral reflection has a similar spectral content/frequency response as the direct sound).

Placing absorption at the lateral 1st reflection points will always change the spectral content of the reflections (ie absorb more higher frequencies than lower frequencies).

 

If you have speakers where the on-axis response doesn't match the off-axis response, then placing absorption and diffusion at lateral 1st reflection points is likely a good approach.

 

I would always recommend running at least 1 well integrated sub - with "well integrated" being a further discussion.

My speaker system comprises Redspade PSE144s + Acoustic Elegance TD18s + single tapped horn T20 sub.

The PSE144s have a reasonable off axis response, so my focus on absorption treatment is in the bottom end - say <500Hz.

 

IME cleaning up your room's response with absorption targeting < 500Hz IMHO will make a significant difference to the "in room" sound.

By targeting <500Hz I mean placing absorption straddling corners and avoiding 1st reflection points - any corner works.

Absorption treatment gets too large/too deep to be effective under 150Hz or so - which is where IME EQ is very useful.

 

IMVHO once you get your room's bass response under control (with treatment + EQ), you're 80% done...and I'm OK to call 80% solutions as "good enough"...

 

...of course you can go further...go for it!

 

cheers,

Mike

[nil]

Thanks for that info Mike - I'm going to remove my 1st reflection panels tomorrow - just to see (hear) what happens. My speakers are JBL horns with 15" drivers which I purchased because my partner would never tolerate PSE144s in our living room. Now please excuse me while I try to find a thread on sub-integration.

[JkSpinner]

11 hours ago, Craigandkim said:

If you want bass, try two or more strategically placed subs

You know, I am a bit of an old school guy, I have always thought that with a very large powerful amplifier and large floor standing speakers, that you should not have the need for additional bass.  But that was before I had any knowledge of how a room might affect SQ.  I am open to that, but will try and make some other changes first.

in saying that, I did have my speakers about 1.6m away from the wall, and the direct sound was quite nice, but severely lacking in bass, so may be subs with speakers out is a bit of a win win

Edited August 28 by JkSpinner

[JkSpinner]

10 hours ago, almikel said:

You should edit the title of your thread as it has a typo - Line not Live

Not sure I can, I think the edit function is time bombed.

[JkSpinner]

10 hours ago, almikel said:

IMVHO once you get your room's bass response under control (with treatment + EQ), you're 80% done...and I'm OK to call 80% solutions as "good enough

The problem is that I do not have a bass problem, either via listening or when measured.  I lack bass <150Hxz.  Although it sounds fine.  I think it is because I have a leaky room.  I am going to experiment a little, I might put. 2.4 x 2.4m bit of ply in front of the glass door, next to the speaker joint the front wall, creating a corner, and see what effect this has.  I might also try the same and block the large opening to the entrance.  This may create more reflective issues, but you can tame them.  And I will also try absorption at the 1st reflection point instead of diffusion, so what effect that has, so bit of playing around to do.

but I will go and have a read of Toole, Olive and Geddes.

Edited August 28 by JkSpinner

[frednork]

Its a journey, and there are many conflicting expert opinions, let alone, practitioners and armchair experts. The more you know the better you can understand the theory behind why people suggest what they do and why that might change depending on room , speaker type etc and what you are trying to achieve.  Great you are diving in. Although it may not give the definitive answer it should help to narrow things down somewhat.

[frednork]

Oh and I have used live end at speaker side but as the speakers are dipoles that is likely the better option for those.

[andyr]

On 29/08/2024 at 7:36 AM, JkSpinner said:

You know, I am a bit of an old school guy, I have always thought that with a very large powerful amplifier and large floor standing speakers, that you should not have the need for additional bass.

 

Yes ... having made the switch to subs - I would suggest that is old-school thinking.  

 

(As is ... big subs can never integrate well with, say, the (almost) mass-less bass drivers which Maggies have!   )

 

On 29/08/2024 at 7:36 AM, JkSpinner said:

in saying that, I did have my speakers about 1.6m away from the wall, and the direct sound was quite nice, but severely lacking in bass, so may be subs with speakers out is a bit of a win win

 

I would say you have hit the nail on the head!  

 

But you need to use a DSP solution to get really good sub integration - so you can, for instance, apply a (or several) low-end boosts to counter your 'leaky' room's lack of low bass.

 

[almikel]

On 29/08/2024 at 7:36 AM, JkSpinner said:

You know, I am a bit of an old school guy, I have always thought that with a very large powerful amplifier and large floor standing speakers, that you should not have the need for additional bass.  But that was before I had any knowledge of how a room might affect SQ.  I am open to that, but will try and make some other changes first.

in saying that, I did have my speakers about 1.6m away from the wall, and the direct sound was quite nice, but severely lacking in bass, so may be subs with speakers out is a bit of a win win

I'm not sure where I read it first, could have been Toole or maybe just here on SNA, but it makes sense to me that main speakers get placed for best imaging, and sub or subs get placed for smoothest bass across the listening positions (eg listening couch).

Great imaging and great "in room bass" are different requirements requiring different placement of the sources - as you have found .

 

I only run a single sub - and the bass response changes significantly moving around my room.

The goal is to optimise your bass response at your main listening position or across say your listening couch.

 

On 29/08/2024 at 7:47 AM, JkSpinner said:

The problem is that I do not have a bass problem, either via listening or when measured.  I lack bass <150Hxz.  Although it sounds fine.

Lack of bass is a bass problem!  

 

Interesting personal story where I thought my bass sounded fine...

...I'd been running my PSE144s on top of my TD18s for a while and considered the bass great.

 

In the space of a week I listened to a friend's system where the low bass literally made the hairs on the back of my neck stand up, then I had other friends come over and we played the Boston Philharmonic Orchestra's version of "Fanfare for the Common Man", and their comment was devastating - "you seem to be missing the bottom octave" !!

 

I started the build of my Redspade T20 tapped horn sub after that!

 

On 29/08/2024 at 7:47 AM, JkSpinner said:

I think it is because I have a leaky room.

I have a leaky room - IMVHO leaky rooms are great!

• Leaky rooms don't keep the low bass bouncing around creating long reverb times.
• Leaky rooms are easier to achieve a tight/dry bass sound without absorption treatment needing to get too large/too deep
• Leaky rooms require less EQ cut for ringing bass that's too low for absorption to be effective 

On 29/08/2024 at 7:47 AM, JkSpinner said:

I am going to experiment a little, I might put. 2.4 x 2.4m bit of ply in front of the glass door, next to the speaker joint the front wall, creating a corner, and see what effect this has.  I might also try the same and block the large opening to the entrance.  This may create more reflective issues, but you can tame them.

IMVHO do not do anything that would reflect low bass back into the room!

Reverberant bass (bass bouncing around the room taking ages to decay) is awful - but typical of many domestic listening rooms

 

The worst is band practice rooms I've been in - rigid besser block walls covered in egg crate foam, reflecting all lower frequencies but soaking up the treble - truly terrible "in room" sound.

 

If you lack bass with your speakers in the best spot for imaging, add a sub or subs - don't try and improve bass by reflecting it around the room!

 

9 hours ago, andyr said:

But you need to use a DSP solution to get really good sub integration

Good sub integration requires further discussion beyond this thread.- but I agree with Andyr.

 

Mike

[almikel]

On 28/08/2024 at 9:10 PM, almikel said:

You should edit the title of your thread as it has a typo - Line not Live

 

On 29/08/2024 at 7:37 AM, JkSpinner said:

Not sure I can, I think the edit function is time bombed.

If you can't, just ask a mod to change it for you...click on the ellipsis (3 dots) and Report Thread, and kindly request the subject line have the typo fixed.

[JkSpinner]

18 hours ago, almikel said:

Lack of bass is a bass problem! 

I agree,  the measurements show it is lacking a bit, and you can hear it a bit, but the bass is sufficient, could be more, but it’s sufficient.  I am going to experiment a bit, I plan to move the speaker back closer to the front wall a bit, and install a small wall in front of the glass door, just creating a bit of a corner, and see what those two differences make.  Then if unsuccessful will look at a sub.

[JkSpinner]

18 hours ago, almikel said:

IMVHO do not do anything that would reflect low bass back into the room!

Reverberant bass (bass bouncing around the room taking ages to decay) is awful - but typical of many domestic listening rooms

I am thinking something small, like 1200 x 900 or something.  it’s also just trying to create some symmetry.

[JkSpinner]

19 hours ago, almikel said:

Good sub integration requires further discussion beyond this thread.- but I agree with Andyr.

Moving my speakers away from the wall and adding a sub one day just might be the answer

[andyr]

6 minutes ago, JkSpinner said:

Moving my speakers away from the wall and adding a sub one day just might be the answer

 

Two!  

 

[POV]

On 29/08/2024 at 7:06 AM, JkSpinner said:

You know, I am a bit of an old school guy, I have always thought that with a very large powerful amplifier and large floor standing speakers, that you should not have the need for additional bass.  But that was before I had any knowledge of how a room might affect SQ.  I am open to that, but will try and make some other changes first.

in saying that, I did have my speakers about 1.6m away from the wall, and the direct sound was quite nice, but severely lacking in bass, so may be subs with speakers out is a bit of a win win

You're absolutely on the right path with your perspective. I often encounter statements on various forums like 'I don't need subwoofers; my main speakers reach 25hz,' which immediately tells me they haven't experienced the remarkable difference that well-integrated and equalized quality subwoofers can make in any system.

 

In my opinion, it's a misconception to view subwoofers merely as tools to extend the lower frequencies. While they do provide this advantage, the primary benefit of subwoofers lies in enhancing bass linearity at the main listening spot and throughout the room.

 

Every setup, in every space, will see a significant improvement from adding two well-designed, high-quality subwoofers that are properly integrated and equalized. There are no exceptions.

[Steever]

On 29/08/2024 at 8:38 AM, frednork said:

Oh and I have used live end at speaker side but as the speakers are dipoles that is likely the better option for those.

 

My Mordaunt Short speakers are dipole (for the tweeters) and rely on some bounce off the wall behind and beside them to throw a wide and open stage. I've previously had Maggies and Martin Logans and like the whole dipole effect.

 

In my previous place, placing too much absorption behind my speakers killed them a bit. Since then, I've read a bit more, spoken to my local treatment specialist and got to know my speakers better.

This time around in my new space, I went with a baton wall behind them for dispersion. Unsuspended cloud absorption went onto the ceiling above head, wall behind chair (1m x 3m only) and floor (thick rug and two layers of underlay). The left wall is all glass with rubber backed drapes. There is no right wall.

 

The results are impressive indeed. 

[Steever]

On 31/08/2024 at 6:40 PM, POV said:

You're absolutely on the right path with your perspective. I often encounter statements on various forums like 'I don't need subwoofers; my main speakers reach 25hz,' which immediately tells me they haven't experienced the remarkable difference that well-integrated and equalized quality subwoofers can make in any system.

 

In my opinion, it's a misconception to view subwoofers merely as tools to extend the lower frequencies. While they do provide this advantage, the primary benefit of subwoofers lies in enhancing bass linearity at the main listening spot and throughout the room.

 

Every setup, in every space, will see a significant improvement from adding two well-designed, high-quality subwoofers that are properly integrated and equalized. There are no exceptions.

 

I used to be in that camp and used to hunt for speakers which played low so I wouldn't have to have additional boxes (subs).

I found that even with speakers which played low, adding a sub or two wasn't so much about the amount of base but what it enhances to other aspects of the system's performance.

My system doesn't use any DSP and I've only "integrated" my sub (a force balanced, ported, bipole design) through trial and error using my ears but the sense of scale and the "bassiousness" I now enjoy with my current speakers is tremendous.

Edited September 3 by Steever

[aechmea]

1 hour ago, Steever said:

I found that even with speakers which played low, adding a sub or two wasn't so much about the amount of base but what it enhances to other aspects of the system's performance.

Too true and then in addition one can place subs anywhere in the room such that there is a relatively even response in listening positions.

 

2 mains playing low + 2 scattered subs = 4 bass sources = many fewer peaks and troughs with no box being stretched out of its comfort zone.  Then add some gentle DSP/EQ as a final touch.

 

Edited September 3 by aechmea

[aechmea]

On 06/08/2024 at 12:21 PM, JkSpinner said:

PS Audio suggested live end in Zone 1 and 2 and all absorption in Zone 3.  PS Audio suggested this resulted in lively sound stage, and very little reflection from the rear.

This is what Linkwitz says too.  To paraphrase, the sound arrives from the front passes by your ears, never to return. 

 

[I have some diffusion at the front and all sorts of absorption at the back (full semi-rigid fibreglass sheets, tube traps, lounges etc. covering the wall) with the seat 2.5m from the back wall.  Has pretty much killed the rear wall reflections.  Works for me.]

 

Then again, 40+ years ago, I went to Alan Wright's place in Sydney and he had the reverse.  The front was full of huge curtains with heaven knows what and carpet?, then you sat on sparse wooden chairs on a tiled area at the back.  Sounded good too.

 

[I only went as company for a mate who was looking for something new/different, but I ended up buying the speakers (Acoustat III)]