[bmckenney]

I'm about to receive 4 Tri Traps and these will be going the room corners obviously.  I also have 3 panel style Real Trap Mini's.  I had these straddling wall corners at first and the result was great, but with the Tri Traps coming I had to find another location for them and so I installed them on a ceiling/wall boundary on one side of the length of the room that has an acute angle at the ceiling (vaulted) as that I was told acute angles are problematic for bass.  I put them there not only because it's supposed to be a good location, but it is a spot that is out of the way from a room aesthetics point of view.  But the results are not that good at all.  I'd like to find another location that gets better results.  I wanted to get a reality check on my plan for locating bad bass build up locations in a room.  I have a pink noise filtered LF test tone from the Real Traps site.  I used this before along with my ears to find bass build up in my room.  Sure enough it worked well but I think this is a crude, inaccurate way of locating bass build up areas.  I say that because pretty much any spot I listened at that you would expect bass build up had bass build up (a rumbling noise that was mixed in with the pink noise).  I suspect my ears are not able to pick up the magnitude of differences, and I think to find better locations for these three panels I need to measure the bass build up instead of listening for it.

I'd like to know if a filtered LF pink noise tone and an SPL is a good way to hunt down bass build up.

[TRADERXFAN]

Why do you think the ceiling/wall is not good at all?
Is this just in comparison to where these traps used to be in the corner?

-Tony

[AB]

What were the results that were not good at all? What did you hear with the Minis placed in the ceiling wall corner? Which corner were they mounted?

I have two Minis mounted horizontally behind my speakers in the ceiling/wall corner. They made a huge, positive difference there. That corner acts like a megaphone directing its bass at my listening position. The traps removed a large amount of the effect.

As for hunting down bass buildup, I have done exactly as you. With a test tone and music and a RS SPL meter, I walked around the room and measured spls. In every corner I had significant spikes. The largest spikes were found in the corners directly behind the speakers. I trapped them all. I still had to do a great deal of work positioning the speakers for best imaging, tight bass and balance. The traps did a lot but they did not perfect the room.

[bmckenney]

The reason I am not that happy with the location of the Mini's is I do not hear much improvement at all.  Certainly not as good as when they were straddling corners on the floor.  I know the corners at either the wall or ceiling are prime locations and I'd like to find the next best locations that hopefully are better than where they are now.  Here's is a picture of the current location.  That is the right wall of a 22*12 foot room.  The top of the right channel speaker is just visible.  The ceiling is 11' high on this right side, and on the left side it is 8'.  So the ceiling vaults upwards from left to right.  This doe not result in any audible channel imbalance btw.  This right side ceiling wall boundary should be good because of the acute angle.  But this side of the room does not have a back corner - it opens out in to a front door foyer.  Maybe that is why I'm not hearing improvements from bass trapping on this side of the room.  As I said, I do have 4 Tri Traps coming and they will be used to treat the 3 corners of the room.  At least one will go in each corner (from floor up to their height of 4') and the fourth one will go either on the front wall behind the speakers along the floor, or maybe I'll stack it on top of the other three traps to give me 8' of height.  And you can see that the front wall (behind the speakers) is windows with venetian blinds so I can't hang a bass trap panel on that wall.  The Tri Traps in the corners and on the floor are probably all that will go on that wall, unless I find with an SPL meter that there is some nasty bass build up in a spot that I can put a panel on like maybe the center of the wall up top by the ceiling. 

[AB]

Can I assume the photo is taken from about your listening position?

Those traps are doing something but they might be too far away from your seat to be really noticeable at this point. I would try to trap the vertical corners floor to ceiling first - sounds like that's your plan.

I found that once I had the corners closest to the speakers trapped the next most effective locations were the corners closest to my listening chair - floor to wall corners left and right.

Oh, and don't forget first reflection points.

The mondo traps will make a huge difference in the front and rear corners. You will be very impressed. Unless you aren't impressed by that sort of thing. 

In any case, I would trap those ceiling corners too but they would not be on the top of the list.

[bpape]

Hang in there.  No - this is not as much as the lower corners but it's a piece of the puzzle.  The other primary places to put things we can't use.

Also, remember that I originally specified 244's straddling those corners.  You chose to swap to the Mini-Traps.  While a very good product, they won't do what the 244's will do in a corner mounting.

244
50Hz - 4.65 sabines
63Hz - 6.26 sabines
80Hz - 16.15 sabines
100Hz - 14.78 sabines

Mini Trap
50Hz - 2.48 sabines
63Hz - 3.35 sabines
80Hz - 7.44 sabines
100Hz - 13.82 sabines

These numbers are directly from our and Real Traps specs pages from measurements done in certified labs.  Below 100Hz, the 244 is almost twice as effective.


Bryan

[bmckenney]

Bryan, I have the products that I want based on the cost and looks I was after, knowing full well they might not be the best from a performance point of view.  I'm assuming while I might not have 244's or Mondo Traps or Mega traps or whatever, the fact that I'm using bass traps at all is a huge plus for me.  And I've heard the RT Mini's straddling the corners so I know that is a good location for any type of trap really.  And I know the Mini's do provide a benefit, even though they don't have as good of measurements as the 244s.  So whether I put Mini's or 244's up on the ceiling, either should work well, even the Mini, if the location needs trapping.  I think we're spitting hairs comparing Sabins on the two products.   I believe for me its the execution or installation or location of traps that is whats really important.

I picked up an iphone today instead of an SPL meter and installed a SPL app on it and just did some measurements.  What a lot of fun the iphone is.  From my measurements I can tell what the bass buildup is along that the ceiling wall boundary where the three Mini's are.  The bass build up is worse closer to the front wall and the windows and gets better moving towards the open foyer.  So I'm going to remove the third Mini from the section closest to the foyer.

And I checked out the rest of the room and the front wall has a lot of bass buildup in the right corner, floor or ceiling.  And it's bad in the middle of that wall as well, floor or ceiling.  And the closer to the left corner, which is diagonal to the open foyer, its not as bad.  And the back left corner, especially up by the ceiling is bad too.

So I'm going to use your 4 Tri's in the corners as planned.  I might stack two of them in the back left corner if it looks OK.  I have some options.  And I'll find a place to put the spare Mini panel too.

Using some sort of measurement, even something crude, is better than guessing.  I believe the products I chose and the locations they will go in is going to exceed my expectations.

[bpape]

Absolutely correct.  You're going about it in the right way.  When you get the others, it will get better certainly.

Yes - the mini's are certainly providing a benefit but I wouldn't call double the absorption below 100Hz splitting hairs by any stretch.  Still you have to do what is allowed in the room.  Given the option by the significant other of the Mini's vs nothing, it's a no brainer.  I was not trying to diminish Ethan's product - simply pointing out the differences in performance in low bass absorption.

The back left corner is something I identified early on and we'd cut back to 1 trap there on the floor as opposed to the stack I originally recommended.  As we discussed, this is largely due to the fact that the left front has no diagonal mode due to the open foyer in the opposing corner where the right front does.  I think stacking in the rear corner is a good idea and then use the mini leaning against the front wall where the additional Tri Trap would have been.

Moving the last mini may or may not be a good idea depending on exactly where it is in relation to your seating position.

As for the iPhone, yes, it's terribly cool.  My wife has an iPod Touch.  It's certainly OK to use to check RELATIVE measurements - just don't take them as accurate when looking for frequency response due to the mic's limitations.

Bryan