psg's future HT room

[psg]

Hi all,

I moved into another house last fall, so gone is my finished basement with 11x33' room. On the plus side, the new place has better dimensions. I haven't yet decided how I will divide up the basement (probably this winter or next spring), but I'm trying layouts out now.

Here's a sketch of a potential layout:

[psg]

Sorry for the hand drawing. Anyway, the odd-looking oblique wall would be added inside the basement (and I'd put a door in it). The 18' back wall along with 6' first edges are outside walls, so i'm stuck with those.

For all summer, I had the KHorns on that 18' wall with my 52" 2-foot-thick RPTV in the middle. The soundstage was very good, with instruments sometimes so close you can touch them, and the bass tight and solid. The problem was sitting 7 feet away from the screen. Note that there are no treatments at all in the room yet: no ceiling, suspended or otherwise.

So few days ago, I tacked up a piece of wall along the oblique line, put a KHorn on the lower-left corner and made up a quickie false corner for the lower-right KHorn (out of table tops). The Khorns are a tad over 21' apart. Imaging is usually good but sometimes not as focused as on the 18' wall. I have lost a lot of bass strength, but not tightness. This is hopefully mostly due to the fact that the oblique wall does exist all the way across yet and the false corner is not adequate. It might also be a bit due to being further away. The real problem with this layout is that instruments and vocal come from spots very far away from where I sit, and I don't know if I can get used to that.

My question is as follows: For those with KHorns about 21" apart, how is the imaging and soundstage? Think finishing my room would change what I hear by a lot? Should I consider keeping this layout?

I have another to draw up for discussion as well.

[PrestonTom]

Looks like you are in for an adventure.

The 21 ft width is fine since it looks like the listner will be about 10 ft back. This gives the proper angle so the you are facing the K-Horns on axis. You will certainly have a nice wide image.

Soundstage is more difficult to predict, partly because it means different things to different people. I will define it as the perceived "depth" of the image(s). It is further complicated since the percived depth is a function of many variables. I believe the major drivers are an empahsis in some of the higher frequency bands (others will debate this) and also a bit of reverberation and "diffusness" from the room (again the debate can go on ...). You have done a quick demo with the quicky false corner, but that is only an approximation. The final one will be tighter and more solid, so I would not worry that it was not as "focused".

Good luck & keep us posted,

-Tom

[mas]

Here's my 15 cents and a quick suggestion:

I would enclose the 3' x 9'7"(???) area (storage, an equipment/multi-use closet, etc.).

I would place the KHorns in the corners along the now 15'7" (???) wall (on the right hand side of the diagram) with the screen in the middle. Then I would place the LaScalas in the corners of the now rear wall (left hand side of the diagram) 'containing' the entrance.

You now have the advantage of an asymetrical room featuring a hioghly desireable splayed side wall which will greatly add in minimizing the effects of early first order reflections (as they will not be as focused, but will be more dispersed), and more importantly, the LF standing waves (room modes). The additional depth, while maintaining a 'nice' wide stage, plus the corner placement of the speakers, will make building the ITD/ISD easier and also will enable building a more dense diffuse semi-reverberent field.

And while I would definately employ some measurements, you would want to employ bass traps, an absorptive ceiling - or if it has any available space above it, utilize a phase grating like the pArtScience SpaceCoupler (hint: I would make them!!!) and utilize the coupled space above the grating to add to the diffuse field, and I would use absorptive panels on the first order reflections relative to the listening positions, and then use diffusive surface treatment over the rest of the surfaces - especially over the entire rear wall.

What may at first seem to be problematic is in fact beneficial! You have the beginning of a room that many should, in effect, be copying!

[psg]

Thanks for the input guys.

I guess I'm a little surprised and disappointed that the KHorns sound better to me 18' apart than 21' apart. I always figured I'd gain with a bigger spacing. So I feel it's a gamble to go with the above plan since I'd have to hope that everything would fall into place with a proper ceiling and proper walls and corners.

I am getting used to the deeper and farther soundstage, but perhaps I should recall my initial disappointment, go with that feeling and try something else.

The oblique wall is not all there yet, just a temporary 8' length tacked to the ceiling joists. The area on the other side of that oblique wall would partly be a corridor, providing an extra division between the staircase door and the HT room (an extra sound barrier). But I could forget about installing that wall, go with a little bigger room with the staircase door opening directly into the room. I could rotate the HT layout by 90 degrees counter-clockwise, without the oblique wall. The TV would fit in the 3' deep opening on the right and a wall and corner would be built in line with the top-right one for the second KHorn. The speakers would be 18' apart, but the TV screen would be 9' away. This might be the best compromise, but I'm surprised that the wider sepration that I have now is not giving me better sound. I'm going to be trying this layout next.

[PrestonTom]

I mis-read your numbers. I thought the 9' 7" was a 4' 7". That makes a difference. MAS 's comment is a good one. You should definitely use that splayed wall to your advantage.

I imagine the 1st order of business is to work on making the room quiet (room-to-room sound transmission). This is not trivial and can range in cost and effort depending on your needs and bank acount. After that I would strongly suggest making some acoustic measures of the room. It is best to do this before any money is spent on absorbers, traps & diffusers. The stuff can get expensive and it should be targeted on specific problems. Depending on how handy & creative you are, some of the treatments can be DIY.

I would get discouraged about the issue of sound stage. That may have less to do with the overall geometry of the room and more to do with room treatments (and a number of other factors). The good news is that you have a decent sized room (it is not 8 x 10) and it looks like you will have control over the set up and treatment.

Good Luck,

-Tom

[psg]

Thanks.

You didn't mis-read. That was 4'7". I should have erased

that before posting. It's the length of the wall that is already

there. I was adding another piece of wall, at a slight angle, to

make a 90-degree corner with the oblique wall (for the Klipschorn).

I have lots of time to try various things anyway. I spent all my

money on hard-wood floor for 4 bedrooms and a corridor on the second

floor, and a bunch of other projects on the house. I have time

before the bank account replenishes. (So much for planned

crossover upgrades.)

[mas]

I am now Very confused by the drawing and the dimensions. What is the purpose of using graph paper if we don't use it to correspond to the dimensions?

If the dimensions on the right wall are actually 6' + 4'7" (using 6 units for 6' and 8 units for 4'7" for a total of 14 graph paper units to represent 10.7' [:S] ) while the left wall is 18' using 17.5 graph paper units, the room is not draw to any uniform scale that I can determine as we are using diffent scales for different parts of the drawing. I think...

What are the correct dimensions?

[psg]

It is to scale. 6'+4.7' is the length of wall that is actually in place. The rest is a possible final layout. That's why i had to make up a false corner for that Klipschorn to test the geometry; there's no real corner yet.

Better?

[DrWho]

Attached is what I'd do - and I think what mas was referring to as well.

This gets you 9' from the screen and 12' from each speaker. They are

each effectively 14' feet apart, but both toed out 10 degrees wider -

getting you a 65 degree angle between mains (dolby and thx recommend 60 degrees).

It's better to have the splayed wall on the side, not on the front

wall. But building it this way you'll have both the side splayed wall

and a front wall splayed half as much - where your RPTV will be

flushmounted in the wall which just looks mega cool. It'll also act as

a better wall to finish the flare of the khorns.

The unused space in the bottom right corner could be used for storage

an equipment rack along the right wall and an enclosure for some insane

subwoofage. Is your RPTV on wheels of any kind? If so, I would just

roll it forward to gain accesss in the rear. Then later down the road

you'll have the option to install a motorized screen to come down in

front of your RPTV for a larger front-projection setup. At which point

you might also consider replacing the RPTV with a lascala for a better

center channel (which would require an acoustically transparent screen).

[psg]

Wow! Thanks for taking the time to actually draw that out!

Certainly something to consider... I have a lot of thinking and testing to do.

Thanks!

EDIT: Does anyone have experience toing out Klipschorns with false corners? I really like the sound of the tradionnal layout. I'm also getiing used to the sounstage with 21' speaker separation, but the bass is still lacking to me (not that it would sound the same with real wall and the room closed-in).

[damonrpayne]

There are a ton of Klipschorn with false corners threads. Look in this forum, 2ch, and "updates and modifications". Good luck with the search feature though!

[j-malotky]

FlyingV is building his HT simular to Dr Whos sketch, puting the Khorns at 30 degrees off center building them into the front wall. He plans to fill the studspace in the cornerhorn corners with sand.

JM

[DrWho]

Sorry for the rushed post - I was racing against the bus schedule yesterday.

I wanted to give major Kudos for exploring the options of splayed

walls. [Y] It's not something many explore, yet is one of the things

that can make the biggest difference. I noticed you went with about one

inch for every foot, which seems to be the rule of thumb.

I went ahead and drew up a slight modification of your original idea.

It's essentially the same except for the added side wall. Right now

with your temporary setup you're probably having issues with

reflections off the side wall that juts out - which will be unbalancing

the stereo image and might explain some of the differences you're

noticing.

Both setups actually put you at the same distance from the screen. The

bottom configuration yields a 90 degree arc between mains and the right

configuration yields a 65 degree arc. I personally prefer to be as far

from the rear wall as possiblem which often opens the option for a

second row of seating.

[psg]

This is interesting. I was thinking that the upper-right La scala was a bit close to the sofa, and that would centers things up.

It might be a good idea to get rid of that cavity on the right, but I would have thought that mid and tweeter frequencies wouldn't be affected by it since they are so directional. The bass might indeed improve without it. You really think it might screw up soundstage? I was thinkg it's because of my temporary arrangement; there no complete back wall there yet and so one KHorn one a much better corner than the other right now.

Your layout would bring me back to about 18' separation, and I guess I'd get back the sound I'm used to. But I'd be back with the TV being pretty close.

The only way to get the TV screen farther while maintaining an 18' separation is by toeing out the KHorns. I've never actually tried doing that. I guess I'll have to try it (but I really like the look of them in real corners).

I appreciate the help and input! Sometimes just talking about it is enough to get the juices going to get the best ideas.

[DrWho]

Just a quick question...why are you trying to get so far back from the

screen? I'm no video expert but I was under the impression that you

should be as far back as the screen is wide? So with a picture about 5

feet wide you could be as close as 5 feet and still be able to see the

entire picture.

As far as the off-axis response...the khorn is a nominal 90x40

dispersion. The bass bins shoot directly to the sides and not towards

the listener so there is a good amount of information in its upper

passband that is trailing down the sides of the wall. And due to the

size of the squaker it most certainly loses pattern control below

800Hz, which means more information going wider than the nominal 90

degree wide dispersion. I would go so far as to argue that this is one

of the reasons the khorn is so picky about the room. 200-800Hz is a

huge chunk of the normal musical content. But even going by the 90

degree wide dispersion you can see how sound is going to bounce off

that side wall and diffract around the corner that sticks out. You'll

be getting a lot of reflections arriving at the listening position that

aren't happening to the other khorn - which by its slight toe-out is

firing more directly into its side wall. The net effect is an asymmetry

- and the first thing to go will be the stereo image. I suppose you

could go a step further and argue that the new reflections might also

be detrimental to the sound too, but I think the asymmetry is the

bigger issue. Anyways, that's just my take on the issue - not trying to

describe it as definitive fact.

I do agree that your temporary false wall configuration is probably

complicating matters a bit too. Have you tried walking around the room

to listen to the modal distribution? It's quite possible that your new

listening position is a null - which will also magnify the issue.

This brings up an important point of the listening position as well.

Since you obviously have some lead way with the configuration you'll

also want to take this into account. I know you're thinking about the

video aspects right now, but the modal distribution and other

characteristics of the room will dictate certain locations being better

than others. The problem with khorns is you gotta build walls in order

to move them around and listen to different setups. But since you've

got lascalas you might try packing away the khorns and see where the

lascalas sound best.

Visual aesthetics come into play as well. Once you start slanting the

walls you have to work against making the room akward to be in. I've

been in rooms that were pleasing to the ear, but the layout was just so

akward that you couldn't enjoy yourself. It could be as trivial as a

bright lamp shining into the corner of your eye - which even with eyes

closed is annoying.

[psg]

Great post... again. Full of good ideas (like using the La Scala!).

I want to get farther away from the TV because it's a 5 year-old 4x3 (non-HD, non-progressive) RPTV. You can pick out the grain when seated 7 feet away from the screen. 18' KHorns puts me 9 feet from the front wall, and 7 feet from the screen of the 2-foot deep TV.

[DrWho]

Sounds like you might need a new TV [] Though I suppose by sitting a good 10 feet away you can prepare for that 120" widescreen in the future []

How far back exactly are you trying to get? And what kind of seating arrangement are you anticipating? 12' back on an 18' foot wall doesn't really leave room for two rows.