World's Most Powerful Subwoofer

dponce80 writes "This $13,000 subwoofer, the TRW 17 from Eminent Technology is billed as the world's most powerful due to its ability to reproduce sounds with frequencies as low as 1Hz. Typical subwoofers bottom out at 20Hz, and while the human ear can barely hear below that point, it is still possible to feel the sound. This particular woofer does not have an enclosure, instead relying on a fan-like design, wafting a cone of modulated air into the room, and effectively turning it into a resonating box, in its entirety!"

Comments

Re:Primitive Audio Weapon ?

[manarth]

Further, it should be understood that most audio mastering engineers will severely filter out any frequencies below 25 Hz as a matter of habit from the old mastering vinyl days

This is because - on vinyl - the lateral deflection of the groove is proportional to frequency (as well as amplitude). So for the same volume, low frequencies cause a groove to take considerably more space on the disk than high frequencies.

This is addressed by attenuating low frequencies (and boosting high) before recording, and reversing this on playback. This is known as RIAA equalization because the RIAA equalization curve became the standard for recording and playback on vinyl.

Not true

[wodgy7]

Most digital audio is not filtered below 20 Hz. That's a myth that persists for a variety of reasons. In the days of vinyl, audio was consistently high-pass filtered because even with the standard RIAA equalization, deep bass produced excessively large grooves. Microphones are sometimes filtered to remove rumble, but in cases where the lowest frequencies are important, such as movie soundtracks, the lowest frequencies are generally preserved, subject to limitations of the equipment, such as AC coupling capacitors. Placing a filter at 20 Hz also has potentially audible drawbacks since the phase shift of the filter will easily extend an octave higher (40 Hz).

Re:It will it hit the brown note.

[commodoresloat]

I realize this is a joke, but there have been studies done of how the body is affected by music. I don't know about the "brown note," but the idea that bass "rattles your colon" is not far off. Interestingly a recent issue of Playboy (I, um, read the articles) had a brief note about this when somebody wrote in and asked what frequencies make women the horniest; it turns out someone did a study to determine exactly that. The frequencies were very much on the low end, though I don't remember. The study itself sounded pretty interesting though - they had various women sit on top of a subwoofer and played different frequencies while asking about their sexual response...

The Inside Scoop

[JRSF0]

I'm the guy who originally dug up the Eminent over at http://www.sonicflare.com/ before I wrote the companion article on ohgizmo.com (which looks dead from a quick and painless /. death...). I'm a blogger, not an engineer, so I really have no idea what I'm talking about (par for course, right) but I did talk to the creator Bruce Thigpen a few days ago about his crazy invention: Yes, it's real. Yes, you can "hear" it below 20hz. No, it doesn't blow women's clothes off...yet. The way the TRW 17 (Thigpen Rotary Woofer model #17) works is the fan spins at a constant speed but the fins themselves rotate back and forth to change the frequency. Also, you don't just set this up in your living room and crank up the volume. It has to be installed in an adjacent space like your attic or basement which then becomes the actual subwoofer enclosure, firing through a chainsawed hole into your main listening room. The TRW was demoed at the Rocky Mountain Audio Fest a couple weeks ago and the reviewers from established audio publications were actually frightened as the walls started to pulse in and out at about 10Hz. Wimps. But the surprising discovery was the sound wasn't booming or nasty, just frighteningly "there." The TRW 17 is advertised with +/- 4dB of distortion which is awesome for any subwoofer, let alone one that covers 1Hz to 30Hz. And here's the good news: Bruce told me there's a cheaper version in the works. Not cheap like free beer, but not 13 grand. Also, there is a car version in the works that, no doubt, has Luda all hot and bothered. A "normal" version is also planned -- normal like a subwoofer the size of a refrigerator but still better than converting the den into a boom machine. So you know, no actual music was played at the RM audio fest. It was purely a proof of concept, though it's claimed to work perfectly for music and HT. I haven't talked to Bruce in a few days (no doubt rappers are all up in his biz after I posted it on Monday) but I'm sure we'll be seeing a lot more of the TRW 17 soon. Pictures of installations and live reports: http://www.sonicflare.com/archives/eminent-tech-tr w-17-part-2.php Josh

Re:Oh bull.

[lakin]

And *that* is what is special about this woofer. Here and here explain it all. Basically, its very hard to move much air at such low frequencies with cone subwoofers (as you saw), so they instead the fan pushes the air with the angle of the blades being adjusted to produce the frequencies.

Re:It will it hit the brown note.

[Antifuse]

MythBusters had an episode trying to recreate the brown note. They couldn't do it.

Engineers don't cut, but media limits can

[postbigbang]

It's rare for an sound/recording/editing engineer to cut off low frequencies, after all this is where there's a lot of percussiveness (and the lowest note of the contra bassoon is actually lower than 30hz). Some used to use roll-off filters that 'shaped' the DC-20hz region, believing there was no information down there, but that's not true-- there is.