I would use Acoustical Solutions assuming I could get fiberglass panels instead of the foam Auralex uses. Foam absorbs the highs but does not do as well with the rest of the frequency spectrum. I think rigid fiberglass has better specs for room treatments than does foam. Sucking out the highs without managing the rest of the spectrum can actually make the room more unbalanced and worse sounding that no treatments at all.
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Just before Thanksgiving I bought a box of eight Lenrd Traps from Guitar Center and installed them in the front corners as two stacks if three.
Wow what a difference. These are an exceptionally cost effective way to tame a large room if you don't mind their appearance. I find they look nice but depending on your room and WAF this could matter.
The soundstage increased greatly, there is more detail and depth to the music and the bass seems like it is now diffuse, non-directional, and all the texture and extension can be heard. I think they are good at removing phase cancellations. Overall I am very satisifed with this purchase and I highly recommend them to all agoners.
I have been doing lots of research like yourself...tons and tons of reading. Broadband absorption is probably the safest bet...unless you are aiming at a particular issue. As Bulldogger points out, there is a risk to make a room worse sounding if you go for something that absorbs mainly in one region. Products that absorb in one region are generally meant to be used to tackle a specific problem or to be used in conjunction with other products. (For example tube traps can be very specific in their absorption)
From my research, foam can be excellent too....especially the Auralex LENRD traps as Stevecham reports (others mail order foams may not be as good...be warned!)....but you will probably need more foam than fibreglass treatments to achieve the same impact. Dow Corning 703 or 705 fibre has higher density (roughly double) than foam and this gives it an edge in the LF absorption per unit of treatment. Realtraps web pages is another good resource to read up on.
Placement is another crucial factor. You can "tune" to a certain extent using the quarter wavelength rule in distance away from a wall (often this is impractical in most domestic settings) If you can't tune by going far from a wall then placement a couple of inches away helps and straddling corners works good too.
I have ordered four of the new type GIK triangular corner traps - so I'll let know my findings when I set 'em up. I believe this is a bare minimum of treatment in order to have some small impact. In theory they should work quite well but I have not seen many reviews, as the triangular versions are new. I liked their prices, which is probably why I took the leap. I won't lose much if they dont work well in my particular room setting.
For the moment, what I am telling you is all based on extensive research and thats it....and we all know the value of first hand experience - so take my comments for what they are worth...two cents!
G'luck and thanks to let us know how many you installed, where they were added, and what was the impact.
I looked the numbers compared to these
Test were made in the same laboratory but sample size was different and one was corner tested and the other against a wall.
Here are the results at 100HZ;
64 linear feet of Auralex LENRD Bass traps = 60 Sabins (A test)
32 linear feet of GIK Tri Traps = 98 Sabins (J Test)
The Tri-Traps are slightly bigger 17" by 17" on the triangular sides versus 12" by 12" for the LENRD's.
The J test is done in the corners = relative advantage to Tri-Traps test.
The A test is done simply against a wall = relative disadvantage to LENRD test results
Very roughly speaking the A Test (against wall) has HALF the absorption compared to a corner at 100 Hz, as the corner is a more advantageous position for bass trapping. (This is a gross approximation)
Normalizing the above data (very very roughly) - here is the conclusion;
One linear foot of GIK Tritrap is very roughly equivalent to 1.6 linear feet of Auralex LENRD in absorption at 100Hz. (when both placed in corners)
It is probably the higher density of Tri-Traps and the fact that they are slightly bigger, which gives them the edge.
Obviously the difference can be evened out by applying 60% more LENRD coverage than Tri-Trap for a given room.
=> the implication is that both options can work equally well and choice comes down to aesthetics/practical issues. In reality, neither will do much for sub 100 Hz room modes for which I think the only practical option is room design and a PEQ. Both should help dramatically with reverberation above 100HZ when appropriate corner coverage is implemented(all four corners treated).
Of course, other absorption designs from other reputable acoustic companes such as Realtraps will work very well too. These are certainnly not necessarily the best options....just a couple of examples. I do not endorse either product and have absolutely no affiliation with either. (Caveat my math might be rusty....so don't take this too literally)
You may want to check out the following links. If you're in to simple DIY you can equal or better about anything commercially available.
This one illustrates the relative cost of room treatment normalized to the effectiveness of the absorber.
TONS of info here for those so inclined.
Thanks Shadorne for extensive analysis. In my room, the Lenrds work well and I found them conveninet and ost effective for my set up. I certainly realize there were other options and for me it was a matter of conveneience and experience with Auralex's products in my home recording studio that led me in that direction. I'm a happy camper in any case. They certainly do make a positive difference in my listening room. Could it be better? Of course! That's one of the reasons why I enjoy this hobby.
Thanks. Great links!
Reading further, to summarize;
It seems foam or mineral wool or fibreglass (or many other materials) of similar density, size and placement can do equally well (assuming appropriate framing)
In theory the higher density materials (up to 8 lbs per foot mineral wool/fibreglass) should get better absorption lower down towards 50 Hz. A slight advantage but seeing as ultra LF is always a significant problem area it is unrealistic to expect miracles.
The size/volume/coverage of bass traps seems the most important.
Corners treated with 16 linear feet of bass trap appears to be a bare minimum and probably brings the largest improvement. Twice that treatement or 32 feet is probably a better but smaller improvement and above this diminishing returns start to kick in (although improvements are still possible, they just won't be as noticable).
Would you agree?
BTW: The reason I am trying to summarize is that there is quite a minefield of opinions on the subject of acoustic bass trap treatments.
Clearly some suppliers are heavy handed in trying to influence the community through comments that are intended to convey that their products are better (fibreglass is better than foam, heavy mineral wool is better than 703, 705 is better than 703, and vice versa, foam is better than fibreglass, 703 is better than heavier mineral wool...etc ad infinitum)
My conclusion is that
1) it is the linear coverage and thickness (at least 6") of materials used that counts far more than anything else; so many products should work quite well...
2) Unless you are an acoustics expert or have hired an expert, it is safest to go for the broadband absorbers rather than tuned devices.
I am trying to share findings with other Audiogoners because, frankly, I found the minefield of opinions quite boggling. Hopefully the acoustic treatments won't head the way of cables/interconects....imagine oxygen free rock wool or gold fibres in acoustic panels (sadly all too plausible). Yikes! Anyone want to form a new company? Perhaps I should be in marketing, LOL.
Shad...There is a ton of info out there, but I think the basics as as you've described them are pretty close to the mark. Ethan Winer is a good source & everything I've read from him keeps pounding on the same basic approaches.
However, not being a slave to dogma...Personally, I'm partial to oxygen & carbon dioxide-free OC 705 that's faced with virgin long-fiber, acid-free kraft paper...framed in old-growth bald cypress, stapled together with 5-9 silver staples & reinforced with glue from long-maned, in-season mongolian mare. Each panel is then loosely wrapped in homegrown, homespun, and unbleached cotton duck. The difference is subtle, but they really open the soundstage up once they are broken in.
ROFLMAO...mongolian mare indeed!
Yeah, I agree Ethan Winer is doing a great educational service. Others seem mostly content to specifically push their products whilst Ethan does a lot more than just plug his own products. He seems on a crusade to put some rational sense into an industry loaded with hype. My hat goes off to Ethan.