PDA

View Full Version : DIY Bass Traps Make Huge Difference



DougMac
05-14-2015, 08:41 AM
I had a chance to stop by the Ascend Headquarters to audition Sierra Towers (which sounded spectacular). I noticed they had some 340's in the audition room, which is what I'm currently using in my dedicated home theater. We hooked them up to give me a point of comparison to the Sierra's.

A couple of things struck me. First, the 340's are no slouches and acquitted themselves well compared to the Towers. I also noticed how much better they sounded in the Ascend audition room compared to home. The soundstage was more expansive, center placement of vocals was pinpoint and the mid-bass "boxiness" I hear sometimes was not there. The audition room is roughly the same size as my home theater, but I noticed the extensive use of room treatments by Dave.

When I got home, I started doing some research on room treatments. I decided that DIY super chunk bass traps would provide the most effective starting point. I special ordered a package of Roxul Safe'n'Sound from Lowe's. The batts are 21.5" wide. I cut the batts into triangles measuring 21.5" on two sides. I then cut same size triangles out of 1/2" plywood. I drilled holes at each corner and used 1" wooden curtain rods for the vertical frame. I slid 2" PVC sections on the posts to hold up each wooden triangle, which were placed 24" apart. The entire trap was 8' tall, the height of the proscenium where my front projection screen resides. I then built frames to put in front of the bass traps, using a black spandex material as my "speaker cloth". The traps are in the corners on either side of the screen.

I started the test with the SVS sub off. There was an immediate and very noticeable improvement. My 340's now sounded like the ones in Ascend's audition room. The soundstage was much better and any hint of mid-bass boxiness was gone. Instruments and voices were more detailed.

I then turned on the sub and found the bass traps made a huge difference in low bass. It was deeper, smoother, more musical and detailed. LFE in movies hit much harder and deeper. I set my system to 75db @ 1,000 hz. I measured at 17hz and got 74db! Measurements up to 80hz were right at 75db with much fewer and smaller dips and peaks.

I have around $100 in the project and I can't remember when I've made such a dramatic improvement for so little money.

I still see Sierra Towers with a Horizon center in my future, but I'm not in quite as much a hurry now. Thanks Dina, Joe and Dave for being such good hosts! Sorry Dave.

Todd WI
05-15-2015, 11:17 AM
Congrats on the improvement, especially given the low cost of the project!

I'm curious if you've done anything to address first reflection points? From what little reading I've done on room treatments they seem to be regarded as the low hanging fruit.

Todd

DougMac
05-15-2015, 11:37 AM
Congrats on the improvement, especially given the low cost of the project!

I'm curious if you've done anything to address first reflection points? From what little reading I've done on room treatments they seem to be regarded as the low hanging fruit.

Todd
I've put some thought into that. The Ascend audition room has addressed it with foam panels. My understanding is that they are pretty easy to identify, you just need a mirror and a helper. They move the mirror along the wall until you can see the speakers from your listening position.

I can handle late reflections from the rear wall pretty easily. I'll have to move artwork and consider aesthetics for first reflections.

Todd WI
05-15-2015, 12:20 PM
I've been doing some "mental billiards" trying to identify potential issues with first reflections. I don't think I have much of a problem with side walls, as they are 6' and 12' from the speakers and somewhat mitigated (absorbed and/or diffused) by a wing back chair and high table and chairs, respectively. I think the recent addition of the Sierra-2s may have reduced any ceiling first reflections due to their somewhat limited vertical dispersion, but I doubt I would have gotten away with putting anything on the ceiling anyhow. I think that leaves me with only a partial wall about 4' behind the main position couch. I'm not sure whether I should be thinking diffusion or absorption for that partial wall.

I really need to get REW up and working to help me answer the room treatment questions as well as some future sub integration questions.

Todd

white_darren
05-15-2015, 05:14 PM
I recently purchased a Rythmik E15 to go with my Sierra 1 LCR setup. Really enjoying this setup. My system is in our main living area which has few vertical corners (all 4 "corners" of the room are actually open to other rooms or hallways). We do however have hard floors with area rugs and lots of windows, so generally a very reflective environment. In this room, I very quickly found that raising the sub up 18" or so off the floor really made a huge difference in evening out the bass throughout the room. Don't hear too many people talk about getting the sub up off the floor. Perhaps most people don't need to if they have wall to wall carpet to reduce floor reflections. Regardless, figured it was worth mentioning as vertical placement offers yet another tunable parameter.

rsmt2000
05-18-2015, 07:36 AM
I very quickly found that raising the sub up 18" or so off the floor really made a huge difference .

Hi

Can you please let me know how were you able to do it? Most of the sub platforms are only few inches in height.

Thx
Ron

white_darren
05-18-2015, 08:11 PM
Hi

Can you please let me know how were you able to do it? Most of the sub platforms are only few inches in height.

Thx
Ron

If you want something fancy, you could look into an ASC Subtrap. A custom made speaker stand / platform would be another option. In my case, I placed the sub on top of a 90 lb, ~18" cube of wood (hollowed out with walls about 3" thick). It's made to be an end or display table but is plenty beefy enough to support the Rythmik.