[Larpy]

I'm using a pair of Pi Audio Mr. T diffusers behind my DIY Lii F15 open baffle speakers. Noticeable improvement in clarity.But I had windows to contend with.  My room is small (12' x 13'), and the diffusers are 42" from the speakers.

[Poultrygeist]

Where do you buy the reclaimed denim batts?

[mikeeastman]

I got denim batts at my local Home Depot, when I built my panels. I also use it in speakers instead of fiberglass.

[JTF]

Where do you buy the reclaimed denim batts?

I picked it up at Lowes, they keep it in stock.

https://www.lowes.com/pd/UltraTouch-R-19-Recycled-Denim-Batt-Insulation-with-Sound-Barrier-15-in-W-x-93-in-L/3731877?cm_mmc=shp-_-c-_-prd-_-bdm-_-google-_-lia-_-102-_-insulation-_-3731877-_-0&placeholder=null&gclid=Cj0KCQjwqfz6BRD8ARIsAIXQCf3t9bNn1IjoKmOrQRr3vuwI2KBZ5JdDB2bpzvmsU_wLgDdvTR9T5aQaAhTTEALw_wcB&gclsrc=aw.d

[sailor]

The 'black hole' is destructive combining of low freq. Bass waves will combine constructively (peaks) or destructively (nulls)

There are two ways of addressing this problem which all rooms have regardless of the type of speaker in use. Bass traps are essential, but for them to really help they unfortunately need to be BIG. The small pieces of sculpted foam sold by amazon etc. as bass traps are totally useless. The wavelengths of bass freqs. are large and the bigger the bass trap the lower the freq. it will absorb. My super-chunk traps in the corners are floor to ceiling and 92cm across. That's a little over 3ft. They are made by stacking triangular pieces of OC703 or equivalent.

The other way of ameliorating the problem is to use a DBA, distributed bass array. 3 or 4 subs are randomly placed around the room which smooths out the bass. This is very effective and the subs do not need to be huge/expensive. There are now many more but very much smaller peaks and partial nulls. A full null is music info missing and EQ can not bring it back. The more power you pump into this null just cancels with the same power!

If you combine proper bass traps and employ a DBA system make sure your first listen has a thick rug underfoot in case your jaw hits the floor 

Small rooms do better with absorption than diffusion and here you want broad-band absorbers. There is a lot of good info on the net explaining all this in detail. Try Toole and/or Geddes re DBA. Audiokineses markets his version, the SWARM.

[FullRangeMan]

Nice F15 OB Larpy, do you could inform us on your xover?
Cut freq etc

[Larpy]

The H-frames below the F15 baffles have GR-Research drivers in stereo.  Each side is powered by a Rythmik 370PEQ amplifier.  Crossover is set at 200 Hz.

[radarnyc]

Hey sockpit
Any update on this? Did you get the panels from GIK? How about some photos and comments? Have you done measurements yet?
As for me, I’m likely going the route that JTF went. I just need to make create some time!
Thanks

This is a great topic for a thread, but a bit frustrating because none of us consumer types have any more expertise than what we can glean from the internet and puzzle out in our private theories.

There seem to be two schools of thought so far:

1. OBs are special enough in their dipolar design that they defy the almost universal advise of acoustic engineers that you need to address bass modes and other sins by putting base traps in the corners (at least) and addressing first reflections, including ideally the ceiling. This is the line of thinking that says doing so will ruin in the magic of OBs, deaden the room, etc. so one should go for Mr. T or diffusion not absorption. (Linkwitz seems to belong to this school.)

2. The other school of thought is that while OBs are less omnidirectional with bass and therefore create less problems and more articulate bass, they are not so special in their physics not to require attacking the bloated bass and reflections that are the bain of every average listening room.  There is a another thread on this Circle that ends with the owner of GIK, saying the principles of treating a room are not that different with OB speakers.

I've decided to go with 2) because both Mike at GIK (see above) and Clayton Shaw, the Spatial owner who sold me my M5s, said full-range bass traps in all corners and also at first reflection point was the way to go.  I'm quite sure Mike would have laughed at the idea of putting a piece of styrofoam diffusion behind my speakers, given his view on the way in which bass reflections kill a small room's ability to render the music clearly. Time will tell if I've just parted with more $ for this hobby without any benefit. 

But what would be great is if Glen at GIK or Clayton could take a moment to talk about the physics of a typical OB design and under what circumstances, if any, bass trapping is to be avoided. Otherwise it's just speculation . . .

[Tyson]

OB's still benefit from room treatments, IME.  For mids/highs, you use a combo of diffusion and absorption.  Where you use each is determined by your room.  In my room, my speakers are far away from the front wall but close to the side walls.  So I use absorbers on the side walls and diffusers on the rear wall. 

If my layout were different and I had my speakers close to the front wall and far away from the side walls, I'd use absorbers on the front wall and diffusers on the side wall. 

For bass, even though OB bass excites way less room modes than a box speaker, they still can benefit from bass traps.  I'm working on getting some built for my room.