# Do I even need bass traps at all?



## Talley (Dec 8, 2010)

Take a look at my graph below. The only treatment I have is a 13' long couch along the back wall and I purchased 4 packs of 2'x4' panels of 4" 4lb min wool each pack having 4 panels each. so I have a 2'x4'x16" thick package of minwool ONE in each corner sitting on the floor up to the 4' height.

This was my result of my SVS speakers and HSU sub which is located in the front center wall. 

I don't have the graph but I removed these 4 packs of minwool and the result was the decay only added about 50ms of decay to the graph below. Like it's effect was minimal at best.

Or is this just saying the bass trapping is not needed at floor level and I need to tray various locations in the room.

My other question is based on the graph below other then the obvious 22hz and below (which I think is some stuff shaking in the room like my ladders leaning on the wall getting ready for paint) do I even need bass trapping?


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## Blacklightning (Nov 22, 2011)

That does look good. Attach your Mdat file. "Go Advanced" button below and press the paper clip (Attachments).
Chose the file and upload.

I do not think any bass traps work below 30hz.


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## Lumen (May 17, 2014)

Just a beginner myself, but I believe improvements can be made. Frequency response is decent, but there's modal ringing up to about 100Hz causing bass "bloat" and midrange "smearing." Bass traps will help by absorbing that excess energy. In the corners behind the mains will give you best bang-for-the-buck. It's best to treat the corner from floor to ceiling, but add-on as budget allows.


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## bpape (Sep 14, 2006)

Just udnerstand you are looking at a 500ms window - most rooms should be more like 300-350ms


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## willis7469 (Jan 31, 2014)

Can you move your couch off the wall any?


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## Talley (Dec 8, 2010)

willis7469 said:


> Can you move your couch off the wall any?


the couch is 4" off the wall but I see exactly where you are going with this.

I'll move the couch to the center of the room and try again.


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## Lumen (May 17, 2014)

bpape said:


> Just udnerstand you are looking at a 500ms window - most rooms should be more like 300-350ms


Thanks, Bryan. The graph shows about 150msec of decay over your 350msec threshold. Is that significant? Do you think it's a good response as-is? 



willis7469 said:


> Can you move your couch off the wall any?


:duh: I missed it... bass pressure-zone is against the wall.


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## Talley (Dec 8, 2010)

I played around with the sub location and found that the HSU 6" away to the right of the center channel... facing sideways toward the center channel which pretty much gets the woofer centered in room and the sub sitting about 3" away from the rear wall and one port open (the port closest to the wall) gave the most even/loudest results. I gained 10db by moving it 3' and turning it.

I also put the sub 6' out from side wall and 5' out from back wall and according to the SIM part of REW would produces the "flattest" bass and it indeed did... in direct mode without tuning it was VERY flat... but it was sitting in front of my left main speaker so it was unpractical. anywhere else and the 90hz dip moves down to the 40/50 range.

Sub in center gives me a reasonably flat response but the decay falls off below 30hz at 500ms and my room noise sits around 43db. above 30hz the decay becomes gradually less the further up.

I have another graph (red) of just the sub by itself AFTER audyssey. 

With these graphs is there any reason to add anymore traps beyond the 4 2x4 4" panels (one in corner each sitting at floor hugging the corner making a triangle)?

Or would more traps help the nulls/dips/peaks in the 100-800hz range? which seems like it's my worse area and main concentration of treatment.


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## Blacklightning (Nov 22, 2011)

Attach your Mdat file. "Go Advanced" button below and press the paper clip (Attachments).
Chose the file and upload.

looking at your graphs is okay but some of us like looking at your data another way.


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## Talley (Dec 8, 2010)

Blacklightning said:


> Attach your Mdat file. "Go Advanced" button below and press the paper clip (Attachments).
> Chose the file and upload.
> 
> looking at your graphs is okay but some of us like looking at your data another way.


Here ya go. This was after placing sub in the location I mentioned and running audyssey. I think bumped the sub hot by 3db also.


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## Blacklightning (Nov 22, 2011)

Okay, from what I can see your bass is fine. Not much you can do below 50hz. And you only other problem is just above 200 hz.

I do see that you have Zero treatment on you walls. Your room is reflecting your speakers all over the place. I would spend some time and money on some basic room treatment (not bass traps).

I included and impulse graph of an SVS speaker in a treated room (red) so you can see how it compares to yours (yellow). You will get some fantastic imaging if you add some treatment and your bass will sound more full with a lot less treble flying around the room. I would also guess that your speakers or LP is very close to the wall.


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## Talley (Dec 8, 2010)

Thank you! Especially for providing some insight.

Yes my room is non treated right now. I do have many more panels and can make any amount of treatment absorption wise needed. My plan was to attack the primary reflection points first with absorption panels and then a few corner traps in my cathedral peaks, two panels above the listnening position and then build some 2D diffusers to place at all other various places around.

The red graph really puts things into perspective on what I'm aiming to shoot for.

So your thinking that with the room treatment alot of the 200-600hz region will improve?

I've put my room together in two months and still working on remodeling my kitchen and painting my inside of the entire home. I got the room functional first and now been concentrating on the painting stuff. I will finish all of that next week and the following weekend I'll be painting my theater walls and hopefully have my screen come in by then too.

Once my walls are painted and screen is up then I'll start doing my absorption/diffusion panels. Wanted to get a decent baseline first so I can track my progress.

...seriously the red graph helps alot.


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## bpape (Sep 14, 2006)

The graph he showed was for impulse response - trying to address stronger reflections within a specific timeframe of the original signal. That won't necessarily help frequency response though with thick enough panels some of the aberrations can be helped at the same time in the reflection zone.


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## Talley (Dec 8, 2010)

bpape said:


> The graph he showed was for impulse response - trying to address stronger reflections within a specific timeframe of the original signal. That won't necessarily help frequency response though with thick enough panels some of the aberrations can be helped at the same time in the reflection zone.


So then I'm left with speaker placement for my only other alternative to remove those very bad nulls.


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## Blacklightning (Nov 22, 2011)

bpape said:


> The graph he showed was for impulse response - trying to address stronger reflections within a specific timeframe of the original signal. That won't necessarily help frequency response though with thick enough panels some of the aberrations can be helped at the same time in the reflection zone.


^ CORRECT

People focus too much on frequency response. Having a tool like REW will help you in all aspects of your room. The biggest upgrade you can do to your system is setup and your room.

Your setup is the best you can do with WAF so you need to work on the room. Bass traps should be low on your list as you have a nice size room and a good sub. Also work on absorbing and forget about 2D diffusers for now. 

I know you can't do this but if you could get your speakers 2-3 feet into the room and your LP 3 feet from the back wall, your sound could really improve. I added my room below in Blue. My room also has no treatment but since my speakers and LP are inside the room away from the wall things are a little better. Your are going to need more treatment because of your speaker positions.


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## Blacklightning (Nov 22, 2011)

Talley said:


> So then I'm left with speaker placement for my only other alternative to remove those very bad nulls.


You do not have bad nulls. I frankly think your frequency responses is very good for your position. Your long room helps.

Your only major problem is the reflextions


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## Talley (Dec 8, 2010)

Blacklightning said:


> ^ CORRECT
> 
> People focus too much on frequency response. Having a tool like REW will help you in all aspects of your room. The biggest upgrade you can do to your system is setup and your room.
> 
> ...



Gotcha thanks. Ya the only thing WAF about my setup is the room has to be setup backwards... screen/seating along the long wall. Right now my head is 2' from rear wall and my midrange/woofer is 2' from the front wall from the cone to wall. the back of the speaker is obviously closer. 

I tried (only left speaker) testing and moved the speaker out from teh wall by 3-4' and moved it all around a around 3' square and tested about 9 spots and the graph really didn't change much but my MIC never moved from the MLP either. 

I just gotta get through the painting/kitchen stuff which will be wrapping up in less than two weeks then I can pick up some fabric and start building my panels. I'm gonna make about 6 2'x2' panels and about 8 2'x4' panels and just put about 4 up and play with 4 of them and take readings and then play around with some other spots.

Since you seen my room I have major echo bouncing back from the crown along the length of the room. I stuck a panel up on a ladder to make a shelf (see photo) just to see what would happen and the "clap" test was super impressive... it KILLED a bunch of the ringing in that particular spot (adjacent to the other side so in the photo where u see the panel I was standing by the main speaker clapping and it was HUGE difference before and after but only in that spot.

So this tells me to maybe build some 1'x4' panels and along the length of the room at the crown areas alternate and cover the crown up with these panels.

Kinda like this:

back wall: >>>____>>>___>>>___>>>

front wall:___>>>____>>>____>>>___

Or at least this was my thought pattern to try first. (i have 16 of the panels below on the ladder which is alot  but got them for 100 bucks so cheap)


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## Blacklightning (Nov 22, 2011)

Good start now you can go one step further and use REW.
I did the same thing as you and I mapped it with REW.

Here is my right speaker in my room with nothing on the wall (Red line).
Now I placed a foam pad on the back left side of my wall and measure (Purple line) 

You can plainly see that the pad makes the reflection at 9ms decrease.
Now place the pad somewhere else and you will see how it affects the original Impluse.

The next photo is the pad placed in another location.

Some say to only work to the reflection to 30 ms.


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## Talley (Dec 8, 2010)

Ya right now my room rings really bad. I'll get there. I'll get the initial treatment stuff (first reflections) done pretty quickly maybe within the next month.

Ultimately this is kinda how I saw my room.

Red is asborption and green is diffusion. The red cloud panels would only be above the three center MLP

My cathedral ceiling means I have a ton of reflections at the crown that I put in. and next at the peak. The peak being the furthest away I was going to load the ceiling/peak with mainly diffusion. absorption in the crown areas and behind the MLP and also the side reflection points.

I also want to make some coffee tables or ottomans where a diffusion panel is mounted upside down under the table so when it's just me listening I can flip them over and have floor diffusion.

Kinda like this chopped up sketch.


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## Talley (Dec 8, 2010)

Here is my back ceiling part and my back wall idea.

Red lines being the clouds that stick out over the couch. green diffusion and red is absorption panels.

My front idea also

none of this includes the bass traps


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