When the back wall just HAS to be close to your head

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mfsoa

Hi Glenn,

I need to set the speakers up on the long wall of my 13 x 18' foot room, so the wall behind the listener is pretty close to the head.

For years I have had a horizontal 242 there, with 2 older GIK diffusers (D2? the wavy plastic jobbies) arranged side by side horizontally above that. My thinking is that if you can't tame the wall behind you then make it go away as much as possible. And then maybe the diffusers would add some sense of space above and behind my head.

It's worked so far but I always wanted to ask -  What's the official GIK-Certified recommendation for treating a wall only a few inches behind your head?

Thanks very much,

-Mike




firedog

Re: When the back wall just HAS to be close to your head
« Reply #1 on: 12 Feb 2017, 07:15 am »
I am also sitting close the the back wall in a small room.

I have Tri-trap bass traps in the front corners, and 2 panels standing vertically in the area behind my head. I think they are also 242's; they might be 244's, I'd have to check.

This seems to pretty much do the job. Before the panels behind my head were installed, I definitely heard "echoes" from the back wall. Now I don't.

Write GIK, they will tell you what panels are best for that situation. They have lots of new models, so the recommendations might have changed.

JWL.GIK

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Re: When the back wall just HAS to be close to your head
« Reply #2 on: 13 Feb 2017, 06:19 pm »
Yes, write in and we can advise to your specific situation for sure.

In general, if the rear wall is close to your head, the best thing you can do is thick absorption, such as the GIK Monster Bass Trap. Absorption is generally better than Diffusion in close proximities, and the thickness means the absorption extends to a lower frequency which will really help even out the low end.

jtwrace

Re: When the back wall just HAS to be close to your head
« Reply #3 on: 13 Feb 2017, 06:21 pm »
Yes, write in and we can advise to your specific situation for sure.

In general, if the rear wall is close to your head, the best thing you can do is thick absorption, such as the GIK Monster Bass Trap. Absorption is generally better than Diffusion in close proximities, and the thickness means the absorption extends to a lower frequency which will really help even out the low end.
I just did the Monsters with the limiter option...

DaveC113

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Re: When the back wall just HAS to be close to your head
« Reply #4 on: 13 Feb 2017, 09:54 pm »
Do anything possible to avoid that situation, even with absorption it's not going to work out well. You'll be limited to a flat, dull 2-D soundstage.

Tone Depth

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Re: When the back wall just HAS to be close to your head
« Reply #5 on: 14 Feb 2017, 12:43 am »
I'd be tempted to just grab a pillow, put it behind my head, lean back and enjoy.
« Last Edit: 14 Feb 2017, 02:06 am by Tone Depth »

roscoe65

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Re: When the back wall just HAS to be close to your head
« Reply #6 on: 14 Feb 2017, 02:12 am »
Ironically, you've got an almost perfect room and layout for the Audio Physic method:  http://www.stereophile.com/finetunes/179/#9mfZbvxo2MDJ0dpw.97.  It is recommended that speakers be placed along the long wall and the listener be positioned in the center against the back wall.  This listener position maximizes bass perception and minimizes the delay from reflected sound, maximizing the Haas effect.  In the ideal speaker position, they are placed midway along short wall and 1/4 of the way into the room along the front wall axis.  What we end up with are two speakers are close the middle of the room as possible with as much space behind them as in front of them.

I would agree that in this scenario absorptive material behind your head would be ideal, with diffusion being a very bad idea.  I do not agree that the listener will lose all depth in this scenario provided he is listening in the near field as illustrated above.  I am in the camp that it is the air around the speakers that contributes to depth rather than air around the listener.


roscoe65

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Re: When the back wall just HAS to be close to your head
« Reply #7 on: 14 Feb 2017, 02:12 am »
Duplicate post.


DaveC113

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Re: When the back wall just HAS to be close to your head
« Reply #8 on: 14 Feb 2017, 04:01 pm »
Ironically, you've got an almost perfect room and layout for the Audio Physic method:  http://www.stereophile.com/finetunes/179/#9mfZbvxo2MDJ0dpw.97.  It is recommended that speakers be placed along the long wall and the listener be positioned in the center against the back wall.  This listener position maximizes bass perception and minimizes the delay from reflected sound, maximizing the Haas effect.  In the ideal speaker position, they are placed midway along short wall and 1/4 of the way into the room along the front wall axis.  What we end up with are two speakers are close the middle of the room as possible with as much space behind them as in front of them.

I would agree that in this scenario absorptive material behind your head would be ideal, with diffusion being a very bad idea.  I do not agree that the listener will lose all depth in this scenario provided he is listening in the near field as illustrated above.  I am in the camp that it is the air around the speakers that contributes to depth rather than air around the listener.

I dunno, I've played with this enough in my own and others' spaces that IMO, you can't get good results if the LP is near a room boundary. Although, maybe a couple inches of fiberglass isn't enough, and if you went to extraordinary lengths (thicknesses rather ;)) maybe it'll work out. In all cases I found it easier simply to move the LP forward. In one case the room was small enough the chair was moved forward for listening then placed back against the wall otherwise, this could be a nice solution.

One of my main goals is a 3-D, immersive soundstage and there's no way I'm going to let setup take that away.

Mike in NC

Re: When the back wall just HAS to be close to your head
« Reply #9 on: 21 Feb 2017, 04:40 pm »
I hope this is not out of line in the GIK forum, but the best result I've had sitting near the rear wall was with 4" thick RPG BAD panels on the rear wall. (I happily use GIK products elsewhere in the listening room, but I don't think GIK has a close equivalent to this.)
« Last Edit: 21 Feb 2017, 07:34 pm by Mike in NC »

Rusty Jefferson

Re: When the back wall just HAS to be close to your head
« Reply #10 on: 21 Feb 2017, 06:52 pm »
Do anything possible to avoid that situation, even with absorption it's not going to work out well. You'll be limited to a flat, dull 2-D soundstage.
I dunno, I've played with this enough in my own and others' spaces that IMO, you can't get good results if the LP is near a room boundary. Although, maybe a couple inches of fiberglass isn't enough, and if you went to extraordinary lengths (thicknesses rather ;)) maybe it'll work out. In all cases I found it easier simply to move the LP forward. In one case the room was small enough the chair was moved forward for listening then placed back against the wall otherwise, this could be a nice solution.

One of my main goals is a 3-D, immersive soundstage and there's no way I'm going to let setup take that away.
I have to agree with Roscoe65 on this one. I recently heard the most spacious 3D 2 channel system to date and it was set-up as he describes. On the wall right behind the listener was hundreds of small random pieces of wood for defraction. Not a single absorber in the room. Quite fascinating. 

JWL.GIK

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Re: When the back wall just HAS to be close to your head
« Reply #11 on: 21 Feb 2017, 07:32 pm »
I'd love to see some test data on a room set up & treated that way. We've all had our singular listening experiences, and they are important. But testing gives us a way to compare more meaningfully.

JWL.GIK

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Re: When the back wall just HAS to be close to your head
« Reply #12 on: 21 Feb 2017, 07:33 pm »
I hope this is not out of line in the GIK forum, but the best results I've had sitting near the rear wall was with 4" thick RPG BAD panels on the rear wall. (I happily use GIK products elsewhere in the listening room, but I don't think GIK has a close equivalent to this.)

Check out our panels with the ScatterPlate, and our Alpha Panels. I don't want to say they are equivalences, but they are in the same product category (ie, absorption and some binary amplitude diffusion together in one unit).  :thumb:

DaveC113

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Re: When the back wall just HAS to be close to your head
« Reply #13 on: 21 Feb 2017, 08:05 pm »
I have to agree with Roscoe65 on this one. I recently heard the most spacious 3D 2 channel system to date and it was set-up as he describes. On the wall right behind the listener was hundreds of small random pieces of wood for defraction. Not a single absorber in the room. Quite fascinating.

That's great, but doesn't mean it couldn't have been better with the LP moved forward...

Rusty Jefferson

Re: When the back wall just HAS to be close to your head
« Reply #14 on: 21 Feb 2017, 08:45 pm »
That's great, but doesn't mean it couldn't have been better with the LP moved forward...
I respectfully disagree, because I heard it. They chose this particular arrangement in a room they could have set up "conventionally".  It can work.

mfsoa

Re: When the back wall just HAS to be close to your head
« Reply #15 on: 21 Feb 2017, 11:36 pm »
Thanks for the input, everyone. All things being equal sure, I'd rather have a lot more space behind me. But I can't rotate things 90° so there it is. There are actually some advantages (pinpoint imaging, juicy bass-hump) that you can have when the rear wall is well damped and close behind. To some extent, room reflections are distortion - (sound that your ear gets that is not on the source) which interferes with hearing what is on the recording. That's just me, I like a pretty dead room. Increase the ratio of speaker sound to room sound.

I like the idea of 2 x 244s vertically behind me with diffusion to the sides of that. I plan on buying some 2" Alphas for the front wall to go with my other GIK goodies  :thumb:

-Mike


roscoe65

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Re: When the back wall just HAS to be close to your head
« Reply #16 on: 22 Feb 2017, 12:29 am »
I'd love to see some test data on a room set up & treated that way. We've all had our singular listening experiences, and they are important. But testing gives us a way to compare more meaningfully.

This is a valuable point.  It may very well be that a particular listener values the response from this particular room.  He may also value similar response in other rooms.

It is too easy to be dogmatic about the "right" way of doing things in this hobby.  Here are some things GIK says to avoid if at all possible:

– Don’t put your seating right against a wall, back or side. This is the worst place in any room for smooth frequency response. This is the central point of this thread.  We can assume that GIK will espouse this philosophy.

– Don’t run your main speakers full range. Get a sub and let it do it’s job. Almost never is the best place for imaging and locking sound to the screen a good place for smooth bass reproduction. Cross your speakers at 80 Hz (this can vary slightly) and put your mains where they need to be. Then you can move the sub around to find the best place for bass response without messing other things up. The side benefit is taking off a huge load from your mains and the amp that’s driving them – leaving more headroom for increased dynamics without clipping the amp.  There are a lot of people who run their speakers full range to great effect.  If we had started this thread asking if we should never run speakers full range and always use a sub, the discussion would have taken a far difference turn.

There are a lot of ways to get great sound at home, most of them compromised in some way, usually due to a lack of space and money.  I would never say something wouldn't work because I've heard too many scenario's that shouldn't sound great defy reason.

Glenn Kuras

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Re: When the back wall just HAS to be close to your head
« Reply #17 on: 3 Mar 2017, 11:27 am »
I hope this is not out of line in the GIK forum, but the best result I've had sitting near the rear wall was with 4" thick RPG BAD panels on the rear wall. (I happily use GIK products elsewhere in the listening room, but I don't think GIK has a close equivalent to this.)

Since you are posting in a GIK circle, I will just say that I bet that our A4 Alpha panel will for the most part match up and the A6 will outperform.  8) :D :P :lol:

Mike in NC

Re: When the back wall just HAS to be close to your head
« Reply #18 on: 4 Mar 2017, 12:14 am »
Thanks,  Glenn.  It's good to get your take on this.

jimtranr

Re: When the back wall just HAS to be close to your head
« Reply #19 on: 7 Mar 2017, 10:22 pm »
Check out our panels with the ScatterPlate, and our Alpha Panels. I don't want to say they are equivalences, but they are in the same product category (ie, absorption and some binary amplitude diffusion together in one unit).

Late to the party, but I agree your suggestion's worth a try.  My listening position near bed center in my bedroom system isn't quite as close to the rear wall as the OP's--but having "borrowed" some scatter-plate as well as full-range 244's and 12"x48" Monsters from my main system to test various configurations, I found scatter-plate 244's at the corners and a full-range Monster at the center of the rear wall to offer the best subjective listening results. Here's a look: