Review: Acoustic Sciences Corp. 16 Tweak

Category: Accessories

I knew, somewhere in the back of my mind, that room acoustics played a significant roll in music presentation in one's audio room (dedicated or undedicated) but I really never paid too much attention to it until lately. I must thank my new found local audiophile friend, who has better ears than mine, who has been thru more equipment, who has listened to more live music presentations & has listened to many others' music systems, for this education in room acoustics. I met my new friend totally by chance when we both could not make it to a (somewhat) local audiophile meeting because we both have little children. We decided that we would have a mini-meeting between ourselves & would audition each other's systems one Saturday. So, he came over to listen to my system 1st. We played a # of tracks (too many to cite here) that tested the bass response, mids & high freq responses of my system. What we found (& after some instructions from him, I listened & concurred) was that my system has a very perceptible & annoying mid-bass boom. The low bass was fine in that the attack on a kick drum came thru with immediate gut-wrenching thump & then decayed almost immediately but the 100-300Hz music signal just hung in the air for just a bit too long & smeared the music. We were feeling a certain pressure in our ears somewhat like you experience during aircraft take-off. We felt the need to pop our ears. I was blissfully unaware of this 'cause I had no one else's system to compare to + my present system is light-years ahead of the system I just upgraded from so I was sitting in my listening chair quite pleased with myself until of course a more learned man than myself came along!
To further ratify this point, this friend kindly consented to bring his TacT RSC 2.2 preamp to characterise my listening room. When we did the test, low & behold, what did we see: 2 very large (10dB higher) bumps at 80Hz & at 200Hz & a gain peaking (about 5dB higher) at 800-900Hz! Mid-bass was a sure problem!! The plot also showed the 1K-20KHz region taking off but that was soon corrected & appeared dead flat when we ran the mic correction/calibration routine. So, this plot exactly corroborated what I was hearing: the high freq, female vocals are vivid & frightening close to reality (dead flat 1K-20KHz plot), the mid-bass was muddy (gain peaks at 80 & 200Hz). The midrange showed a gain peaking but it must have been masked 'cuz I couldn't really tell that I was suffering at its behest.

So, I set out to get some tube traps. The DIY Jon Risch variety were very tempting but it took too much time to make esp. since I was never absolutely exempt from baby-sitting duties (to help my wife) over the weekend. In the end, a nice audiophile put 8 up for sale. They were a motley of ASC tube traps in that some were 4' & some 3' + some were 16" & the rest 12" diameter. Anyway, the best deal from him was to buy the lot, which I did & paid thru my nose in shipping! Actually, in retrospect it wasn't that bad but it came as a surprise at the time of clinching the deal.

The 8 ASC tube traps are silver/papier in colour & seem to be the most neutral colour they make.

There is much too much theory & practical knowledge about the ASC tube traps to even begin citing here. So, all I will suggest is that the reader, who is not up-to-speed on ASC tube traps, search the AA archives + read all the material on Jon Risch's website.

I have tried a number of placement options on a daily basis over the 1st 2 weeks of acquiring these traps. I think that I have finally reached the best compromise. I say compromise 'cuz I feel I need more than 8 ASC tube traps for my room!!! My budget won't allow for any more for sometime atleast. So, for right now, I have 4 4-ft 16" traps along the wall behind the speakers - one in each corner & one directly behind each speaker. The ones in the corner are fully reflective & the ones directly behind each speaker are fully absorptive. My speakers are just 44-45" from the back wall so I get reflections that reach me within 10mS & cause a music smear at my listening position. If your speakers are the optimal 5' or more, it is very likely that you will not need one directly behind the speaker. I have one 16" 3-ft trap along the rear wall behind my listening position - fully absorptive. I have 2 12" 3-ft traps mid-way between the speakers & my listening position with their full reflective side facing me. I have 1 16" 3-ft trap along the side wall between the mid-room trap & my listening chair - fully reflective. I know that the 3' traps need to be atleast 4'. When the money becomes available I will buy some more 3' traps & stack them. Right now, I feel that these traps are located in key positions & have taken my listening room acoustics to Cloud 9! Before, when you walked into the room & were conversing, one could hear the walls reinforce the voices. Now, when you walk into the room, it sounds deathly quiet just like an auditorium. If you don't make a sound, you can hear yourself breathing! Much less is bouncing off the walls. A good 1st indication I told myself.

Wow! When I heard the 1st track of my one my "test" CDs, I nearly fell from my chair! Could my system sound so clean?

The 1st track I played was #11 from Diana Krall's "Love Scenes" CD. The track begins w/ fingers snapping & then there is a bass guitar riff for the next 45-55 seconds. Now, the sound is very clear - you can hear as he plucks each bass guitar string. The sound from the previous plucking dies out well in time for you to hear the next one. These 45-55 seconds are non-stop & merciless for the mid-bass region so if your system fails here, there is no time *at all* for it to pick itself up. Before, my system made one soggy mess of these 45-55 seconds (ever tasted corn flakes left in your cereal bowl for 20 minutes??).

Another track: "Love comes tumbling down" from U2's B-sides CD. The tracks commences with a short guitar riff that sounds like it was played in a large hall - there is a certain "big-hall" quality about it. Then there is one sharp "twwaacck" on the drum then dead silence then the song starts in right earnest. That single drum "twwaacck" is very startling & on loud volume will make you jump. The impact of that after placing the tube traps is phenomenal - great startling factor for your unsuspecting friend who comes to listen!

Yet another track: #7 "If you don't know me by now" from Simply Red's Greatest Hits. Through-out this track look for the snare drum attack. It's best rendered in the beginning when many other instruments are not playing. Each time the drummer hits the snare, it is without mercy, without remorse & it sounds like a gunshot! The impact of it after placing the tube traps is tremendous - full force. I am not a drummer but I have been made to understand that snare drums often have a wire-mesh either inside or below that impart a certain metallic sound to it. Indeed true on this track #7 - when the snare is hit, you 1st hear the drum stick on the drum skin but as the sound dies out there is a "TSCHHHHHhhhhhh" that follows. Almost makes you feel that he hit the snare & cymbal exactly at the same time (but this is not the case, I'm made to understand). This disctinction in sound is now very clear after the tube traps are in place.

We have played a number of classical music CDs on my system now - Bach, Mozart, Beethoven, Sibelius, etc, etc. The sound is much improved now. In particular, before the tube traps, the violins (which are supposed to be in the left orchestra) were moving! When there was a solo, it was distinctly in the left channel but when the orchestra violins accompanied, the sound was left ch. sometimes & sometimes it moved to the center! My friend thought, for sure, I had the speaker or interconnect polarity reversed! We checked it thoroughly & they were all just fine. Now, after the traps are in place, the violins are in the left ch & they stay there whether it be a solo or the entire orch. violins playing.

I have not re-measured the room with that TacT again but my ears tell me that things have improved by a quantum leap. The traps have had a side-effect of improving the low bass as well - tighter now. The high-freq has been untouched to my great relief. That area was never a problem in my system & I was apprehensive of the tube traps ruining/muting that spectrum. I am happy to say those fears are now gone.

These ASC tube traps are really fantastic & they work so well yet the idea is so simple! A hollow tube with care taken to create a sandwich of materials of the correct type to absorb unwanted bass resonances. If you look thru History & see all the patents granted to all the inventors, usually it is the simplest rendition of a particular problem that is patented! When you read it & understand it, you slap your head & say "why didn't I think of this?!". So, too with these tube traps. Bloody expensive but highly recommended. Roll your own thanks to Jon Risch or buy the original or buy an equivalent from Echo Busters, Rives, The 8th Sense, etc-set aside some money to have these or some room treatment in your listening room - you will really hear what your system is capable of.

Highly recommended!

Associated gear
Amplifier: Symphonic Line RG4 Mk3
Preamplifier: CAT SL1 Sig. Mk 3
Speakers: B&W DM604S2
Cables/Interconnects: Groneberg TS Premium & Tara Labs RSC Master Gen II
Music Used (Genre/Selections): Classic Jazz, Modern Jazz, Classic Rock, Blues
Room Size (LxWxH): 19' x 17' x 9'
Other (Power Conditioner etc.): RGPS 400S

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