# Living/HT layout



## cellexjohn (Jan 25, 2007)

Well, I would like some input on where to start with room treatments. I have a funky floor plan open to other rooms and a hallway. As you can imagine their are closets and bedroom doors to deal with also. This should give a good idea what up up aginst.

I have a REW graph in the BFD/REW area if interested.

See what you think.









All questions and coments welcome.

Thanks,
John


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## Sonnie (Apr 11, 2006)

Do you have a REW full range response graph... or just sub response?

Post what you have here anyway... but a full range response would probably help more.


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## cellexjohn (Jan 25, 2007)

I do have 20 to 20k with the new analog RS meter. I wasn't sure how accurate it would be.

Full sweep 1/3 smoothing.









Thanks
John


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## Sonnie (Apr 11, 2006)

Yeah... the RS meter is really only good up to about 8KHz or so.

The BFD can take care of that nasty peak at 45-50Hz while probably the right combo of traps and panels could help with the rest... mainly the peak at 140Hz and 4-7KHz.

Maybe some of our acoustical experts can give you some suggestions on what to try.


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## bpape (Sep 14, 2006)

Turn off the smoothing - it masks a ton of real world issues. 1Hz resolution is best - 1/12th octave is about a minimum. 

Is rearrangement an option?

Bryan


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## cellexjohn (Jan 25, 2007)

Here is the graph with no smoothing. I thought somewhere i read to turn on 1/3 smoothing on 20 to 20k graph. My bad.









Im not sure how to change to 1Hz resolution. I tried to upload the .mdat but it's too big.

Thanks for the reply
John


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## bpape (Sep 14, 2006)

OK. That looks 'better.' Can you replot and post with just the 20-400 range showing please. That will allow a better look at exactly what frequencies are having issues.

In general, there are a couple of issues. 

First of all the AV rack in the front right corner is taking up an excellent place for a bass absorber. I'd move it if at all possible. Second, that hall in the lower left is absolutely going to cause upper bass/lower midrange resonances but not sure what can be done.

I am assuming you have this arrangement so that the TV can be seen from the dining area. If that's not correct or not a big deal, then I'd look at putting the TV/audio in the upper left area turned 90 degrees to get better symmetry, allow treatment of both front corners, and get you more out of the way of the other obstacles.

That's a narrower setup and you'd likely have to do some sort of riser for a 2nd row but I think it would be worth it. Not knowing the aesthetic and spousal considerations, I'm not sure how feasible that is though.

Bryan


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## cellexjohn (Jan 25, 2007)

Thanks Bryan,

I will post the 20 to 200 when I get back home. 

On the rearangement, to the left is a door in the left corner to the master bedroom and to the right of the bedroom door is a closet. I would not be able to relocate for that reason. 

There is room between the closet and the corner wall for an 18" by 8' panel or a corner trap. I also planned on doing the exact same on the corner behind the AV rack to keep things ballanced. The corner to the left where the bedroom door is only has room on the left wall if you are facing the bedroom door. Kind of hard to picutre huh. he he

John


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## cellexjohn (Jan 25, 2007)

Here is the full sweep file with 20 to 200 limit.









I have been ready about the diy panel traps from ethanwiner.com. That is the design I was most interested in. 

Thanks again
John


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## bpape (Sep 14, 2006)

That's actually surprisingly decent. I'm sure the decay times are still way too long but I've seen a LOT worse raw FR graphs.

The panel traps on Ethan's site are more narrow in nature - maybe 1.5 octaves wide each. They're also not as efficient per unit area as a soft broadband velocity absorber (the panels are pressure absorbers). You may find that a mix of the 2 types may work best for you.

Bryan


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## basementjack (Sep 18, 2006)

1) I think you have a great room acoustically - lots of variety means your low freq response should be pretty decent off the bat, and your chart shows that.

2) when you take your rew measurements, you might want to take several from different positions.
I expect a different reading from the left couch seat to the right - possibly significantly different.

3) if you're interested in room acoustics, check out cara (www.cara.de) - cara can model your room's acoustics, and then in cara you can add acoustic panels and see what the impact is.

BTW thats a nice drawing - what did you use?


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## cellexjohn (Jan 25, 2007)

Bryan,

Glad to hear I have a decent start without treatment. 

My plan was to start with the "deep-base" traps in the 3 main corners to the front right, and to the far left in each corner. The next planned step was to mix "mid/high" base traps with "high" base traps along the wall behind the TV. I plan to hit reflection points higher up the FR along the sides, rear small wall behind the couch, and ceiling last. I'm going to run out of wall space quickly. he he

Does that sound like a good approach? Or am I going about this all wrong?

John


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## cellexjohn (Jan 25, 2007)

Thanks for the reply Jack,

When I first got interested in graphing my room I figured that the layout was going to be horrible. After reading in here a bit it seemed there was some talk about open rooms could possibly be an advantage.

I havent moved the mic from the orginal position yet. Thanks for the reminder. 

I'll check out the link for some more info. Useful information seems to be the one thing you can't get enough of.

I used google sketchup. It's much fancier then needed for what I made. Pretty cool program. I saw someone else used it in another thread.

John


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## bpape (Sep 14, 2006)

I'd go broadband in the corners to start with. Solid chunk style absorbers will reach down pretty low and help with the decay times across the board. The membrane absorbers can be added in other places later - but not generally in the corners.

Bryan


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## cellexjohn (Jan 25, 2007)

Bryan,

When you say solid chunk, what material are you suggesting? 

I can "build" across 2 of of the far corners to the left and right of the sub. I have 19.5" form the corner to the door trim at the far left, and 8' ceiling in the corner to play with. I figured I would keep both sides the same to make it look even.

Thanks again,
John


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## bpape (Sep 14, 2006)

To do an 8' tall, 17x17x24" solid chunk, you'd need about 12 pcs of 2" OC703. Each pc will yield 8 pcs (16 vertical inches) at the 17x17x24" dimension.

Bryan


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## cellexjohn (Jan 25, 2007)

I was thinking that's where you were heading. 

So in your opinion, is that going make quite a difference? I believe that the the sheets of 1" Johns Manville (475) were $23ea. that puts each corner around $550. I have not been able to find anyone in lafayette that has Owens Corning, and I have to borrow a truck to boot.

John


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## cellexjohn (Jan 25, 2007)

Well progress on the first "chunk" corner trap has gone well. I finished one last night and hopefully will get the second one done today. 

Here are a few pics of the process.

Enjoy

































I plan to make a "pillow" with insulation for the top and bottom.

I am verry happy with my first DIY trap.

John


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## bpape (Sep 14, 2006)

Sorry to be late responding to this. Hope you didn't pay that much for 1"! Even with shipping to the West Coast, you can get enough 2" to do 1 corner for about $100.

Very nice job on the 1st one. I think you'll be happy with the results.

Bryan


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## F1 fan (Jul 6, 2006)

Great looking trap John.:T


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## cellexjohn (Jan 25, 2007)

Hey Bryan,

I ended up ordering it from ATS Acoustics. They are in a neighboring state. I ordered it on Fri. and had it Sat. The price was fair.

I used 2" mineral wool for the bulk of it and faced it with 2" OC703. It definitely makes that corner sound different. I'll have to run a graph with just one trap to document the difference.

John


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## cellexjohn (Jan 25, 2007)

Thanks F1 fan. 

John


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## basementjack (Sep 18, 2006)

WOW John, 

That Trap looks great! Really blends with your room well.

Looks like you used rockwool on the bottom, and rigid fiber in the front - how deep is the front?

Also there's a place in Illinios called fabricationspecialties.com that does custom work on insulation - if you wanted to go solid, you could probably buy 4" thick and have them cut the triangles and ship it to you. They are great people to work with.


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## cellexjohn (Jan 25, 2007)

Thanks Jack,

It is 14 inches from the wall corner to the front with 27 1/2" face. It's 7' top to bottom. If it wasnt for the closet I would have gone wider as that part of the room is a total waste in my house.

This has been a fun project! I'm excited about building some soffits. I have alot of availabe space on 3 of the walls. After seeing what the finished product looked like i have no problems with doing more.

John


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## Prof. (Oct 20, 2006)

That's one of the neatest corner traps I've seen...great job..
What material did you use to cover them? 
I've just finished my corner traps, but their not covered yet..I'm thinking about using black burlap..


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## cellexjohn (Jan 25, 2007)

I looked at the burlap and found the same color. The guy at the fabric store suggested this instead to hold in the insulation fibers. It is a very open weave but not quite as much as the burlap. I dont remember the name but when I go back for more I will find out.

The reciept from Jo-Ann Fabrics says Osnaburg? Not sure if that helps.

Thanks for the compliment> 

John


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## cellexjohn (Jan 25, 2007)

I finished the right side. I had to move things around a bit. 

Should I leave the spaker in the corner like it is now, or move the AV rack to the corner instead? I wasn't sure so I figured I would try it here first.

Any opinions on the position?









Ignore the wires, the game was starting. :innocent: 

Home Theater Shack ROCKS!

John


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## Prof. (Oct 20, 2006)

Personally I prefer the speaker spacing as it is now...but I would find having the equipment rack next to the TV like that, very distracting..
Can the rack be located elsewhere in the room?


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## Sonnie (Apr 11, 2006)

I agree with Prof. I wonder what the AV rack does for your speaker being right next to it like that. Maybe you could push it on back right up against the wall between the window and the trap.


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## JCD (Apr 20, 2006)

Coming in late, but wow, that is a great looking trap. Have you run any graphs to see what changes it made?

JCD


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## cellexjohn (Jan 25, 2007)

Thanks JCD,

I am planning on running some tonight. I want to reset my phase and sub position if need as I moved the mains in relation to the sub. Hopefully I will have something for tonight or tomorrow.

John


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## cellexjohn (Jan 25, 2007)

I have been pondering the thought of where to put the AV rack. I really don't have any other options except going to the left side of the sub which is 12' away. To the right of the couch by the little wall would be great but I have a register there.  My room layout is really funky.

What graphs are most useful for seeing my results? The LF decay or LF waterfall? Or both. I have to research them as I don't understand that part of the program yet.

Thanks

John


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## DrWho (Sep 27, 2006)

Is there a wall behind that couch to the left? Or is it just a big open area?

As far as the graphs, the spectral decay and waterfalls are showing the exact same thing - just two different ways of looking at it.

The graph you really want to look at is the Energy Time Curve. This will show you the time arrival and relative magnitude of every reflection that hits the microphone. As you implement bass trapping, you should notice spikes (reflections) being reduced in magnitude. You should also notice periodic spikes being reduced, which means you're reducing the ringing of your system too (a waterfall is really the better tool for viewing that change). Once you tame the bass response, the next step is to increase the length of the initial signal delay ("ISD" - which is the time between the initial impulse and the first reflection), etc etc...

The cool thing about the ETC is that you can determine where acoustical treatment needs to go (by taking the room geometry and speed of sound into account - roughly 1 foot travelled every 1 ms). Sometimes you'll have multiple possibilities so you'll have to try a spot and remeasure until you knock out the reflection you're aiming for. Just keep in mind that small rooms don't have a true reverberant field - so diffusion is always preferred over absorbtion (except maybe at the higher frequencies where the room is effectively large enough).


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## cellexjohn (Jan 25, 2007)

Mike,

It's a wall behind to the left. the white area is a closed utility room and the white square is the bathroom. 

I looked at the waterfall graph with the time range upped to 500ms. I will play with that tonight. I'll take a look at the ETC also to make sense of it.

Thanks for the help Mike.

John


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## cellexjohn (Jan 25, 2007)

Here are a couple graphs to show the difference with and without the 2 corner traps. EQ inline but not active.

Feel free to coment.

All energy time









Waterfall 

before traps









Waterfall 

after 2 traps









Thanks for any input.

John


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## terry j (Jul 31, 2006)

good work john

just to make sure in my own mind, the (lovely looking) corner trap is solid f/glass behind the facing f/glass yeh? ie no airgap.

also, with your waterfalls, you may find it useful to superimpose the two graphs on top of each other, in the new program it is found under the 'more waterfall controls' tag. It also makes it easier to see them on the shack as otherwise the graphs are spaced 'far' apart and it'd difficult to see both at once.

keep up the good work!

subjective impressions so far?????


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## bpape (Sep 14, 2006)

Well, the decay times have begun to come down a bit - looks like more work still to do but better. 

I see some improvements in decay times and a slight smoothing of the frequency response. I suspect that much of what you're seeing in the response curve is due to speaker placement close to the front wall and directly beside the TV which is offsetting the xover baffle step response. Is there a boundary switch on those speakers?

Also, it appears that there is still a small travelling wave at about 60Hz. Also looks like there is some contamination of the signal -either electrical or acoustical as shown by the constant low level peak at a tad over 100Hz. The other travelling waves appear to have gone away.

Bryan


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## cellexjohn (Jan 25, 2007)

Hi Terry,

Behind the 2" 703 facing is 2" mineral wool triangles with no air gap.









No impression so far. I really havn't done any critical listining with the new speakers. I picked them up 2 weeks ago. I have been concentrating on treatment. I ordered some 1" 703 for first reflections and bought more material for that and more corner traps. I am hoping to start treating some wall to ceiling corners this weekend.

Thanks,
John


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## cellexjohn (Jan 25, 2007)

Hey Bryan,

There is no boundary switch. I don't even know what that is. 

What are your suggestions for 60Hz and 100 Hz issues. Will more treatment help? How do I hunt down the culprit if it's electrical?

Thanks for your input, it is greatly appriciated!

John


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## DrWho (Sep 27, 2006)

Hey John, were these measurements taken with just the subwoofer? You should tweak the scale of the graph a bit so that you can see more of the sound's decay. Right now we're not even able to see all of the direct sound (especially in the higher frequencies).


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## brucek (Apr 11, 2006)

I'd prefer to see the waterfall in logarithmic scale rather than linear ................


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## cellexjohn (Jan 25, 2007)

Mike,

Do you want me to up the time range or run another sub only graph with a higher end point?

John


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## cellexjohn (Jan 25, 2007)

Brucek,

As requested 










John


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## cellexjohn (Jan 25, 2007)

Hey all,

Here is a picture of my attacted dining area. Should I go ahead and do these corners also? Or should I concentrate on the ceiling to wall in the living area?









John


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## DrWho (Sep 27, 2006)

cellexjohn said:


> Mike,
> 
> Do you want me to up the time range or run another sub only graph with a higher end point?
> 
> John


You just need to change the amplitude scale to go lower in frequency. So instead of 45-105dB, perhaps something like 35 to 95dB. Also, on the ETC plots, they're more informative if you scale them to % instead of the dB scale (and make sure it's normalized too).

As far as your waterfalls are concerned - one thing you might try to do is walk around the room and see if you can't find corners where there is build-up over that 45Hz-ish frequency range. You could probably even set REW to play some test tones in that region so that it's easier to find. I've never tried this, but I would think the steady state build-up points would be the major proponents contributing to the resonance. You could always verify by looking for peaks in the ETC that correspond to the extra distance travelled by the reflection.


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## bpape (Sep 14, 2006)

The corner where the chair is won't hurt for sure - personally I think the cat is the problem 

The longer issues at lower frequencies are likely either a noisy fan in the PC, maybe an HVAC system running, etc. 

The boundary switch would have modified a few values in the xover of the speaker/sub to account for being so close to a wall. When you get the extra material, try about 4" of it right behind the speaker.

Bryan


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## cellexjohn (Jan 25, 2007)

Allright,

Here is a 35 to 95dB waterfall. I am leaving the EQ out for these graphs. I figure I don't need to post the pre treated graphs anymore.










Here is the ETC at %









I played some bass heavy material and the two corners in the dining area both get boomy. I will try to work on on one of them this weekend as I olny have enough material here for one more corener trap.

Thanks for the help! 
John


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## cellexjohn (Jan 25, 2007)

Bryan,

The cat should act as a bass trap. If you saw this cat in person, you would understand. 

I actually pulled everything off the walls last night. I turned off my ceiling fan and chased rattles before plotting. The problem is that I had the EQ on the whole time and didn't realize until I put the measurement equipment away.  The only thing running was my HD DVR and it has a fan that runs quite a bit. I'll have to make sure it's off for the next set of graphs.

The distance of the drivers from the back wall are currently 34". When you say 4" right behind the speaker, you mean touching the back of the speaker right?

Thanks again Bryan


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