Acoustical Solutions or Auralex LENRD bass traps

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.

Ecruz,

Good suggestion. These are 2 Lb density which I believe is equivalent to Auralex. These Agon threads are so handy!

Stevecham,

I looked the numbers compared to these

Tri-traps

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)

Fishboat,

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?

Fishboat,

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.

Fishboat,

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.

I just received and installed four of the new type GIK Acoustics Tri-Traps. You can see photos of them and where they are placed from my virtual system or the following links.

Two Tri-Traps Rear Right

One Tri-Trap Rear Left

One Tri-Trap Front Left