Eminent Tech TRW 17 Part 3

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by Josh Ray on November 01 '05

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Here is part 3 of our Eminent Tech TRW 17 coverage (part 1 and part 2). Now, some disbelievers seem to think that all this is just a hoax. First, RTFA before you open your yap. Second, RMAF drew tons of visitors (Rocky Mountain Audio Fest, FYI). Third, OMG was how everyone described the TRW 17.

Read the rest of the article for some exciting news from the maker of the TRW 17.

I spoke with Bruce Thigpen of Eminent on Monday and he confirmed everything I posted (except for the part about "clip and turn your house into a smoldering crater" -- it's more "mushroom cloud-like," he said). Now, to be clear, no actual music was played at RMAF, only test frequencies, so we don't fully know what this will do in the real world. I'm sure we'll be seeing some demos soon and, naturally, we'll keep you updated with the results.

Now, about that $12900 price tag, Bruce did have a little something to say: "we should be able to get the price down next year to something more reasonable." Yeah, I know some of you are squealing like little girls right now, admit it.


Ka-boooooooom! Ka-boooooooom! Wonka! Booom-Boooom-Boooomity-Booom!
Wow, sounds real cool, thx for the 'low down' :) I'm of to my local hardware store now for the juiciest fan I can lay my hands on!
You do realize this *thing* is going to have some long term effects on the structural integrity of people's houses? I can't begin to imagine what'll happen if you manage to hit a house's resonant frequency. If that thing pumps out enough power, you could probable shake a house to pieces by setting up a standing wave.
Isn't the limitation of the woofer now going to be the sound source? I don't know of any recordings that have frequency responses below 20Hz. CD, DVD, AC-3, HDCD, don't they all cut out at 20Hz?
The CDs themselves are normally cut at 10Hz unless you master them not to. Though , I have never seen any mastering software that allows audio below this either, not that I have looked alot be be honest. However, most preamps and other audio gear also cut at approx 10 Hz either due to that they are designed to do this to prevent damage to loudspeakers (DC kill speakers) or that they contain caps in the audio path that makes it impossible for frequencies below 4Hz to pass. So, in essence, specially mastered CDs, CD players and amps are needed to feed this bass beast.
The span of the human ear response is traditionally assigned from 20 Hz to 20 kHz. So why need lower frequenties in music? Bit of a macho thing this.Also it says they only played some test frequencies with it. I wonder if it could cope with real music.
The reason to drop below 20Hz is not to hear the sound but to actually feel it. It will make movies much more realistic because you will be able to feel explosions and whatnot as they happen....
Jeroen, Yes, while the average human ear cannot actually generate meaningful information from frequencies below 20hz, the lower frequencies do alter the harmonics of higher freqencies and infrasonics can be 'felt' more than 'heard'. From 43hz down is a very important part of the musical spectrum; too bad most folks these days over-saturate that part of the spectrum.
Test tones and special effects - sure. Butt shaker and room ventilation at the same time. Music? Naah. Assuming that the tone is based on the RPM of the blade, there will be latency in changing the speed of this thing will limit the ability to change frequency quickly. Unless, this operates like a helicopter and the pitch change is based on the angle of the blade... doubt it though and same problem.
RTFA. If you read the frickin' article, you would know that it does change frequency by changing the pitch of the blade. I mean, do you know how bonzers this thing would have to be to do it by changing motor RPM? Do you know anything about motor theory? If you tried to force a speed change at the rate necessary, you would just end up with pole slippage anyway. Of course they're altering the pitch of the blades. Did you think the 13 grand price tag was because the blades were made of gold?
No, it does'nt have to change rpm to change tone.. The way it works is pretty simple, the blades are variable pitch. All that means is the blades can rotate to produce both blowing and sucking. amplitude is how far the blades rotate, and how fast they "wobble" is frequecy.. But id like to know how music sounds on it.
Maybe with a new found demand for subsonic worthy recordings, maybe "professional" recording studios (no names, you know who you are) will use real acoustic designs next time they revamp their rooms.. Nothings worse than obvious LF phase problems due to room modes. Want to make you nearfields not suck?.. fix your room. Great speakers sound awful in a bad room. You know who you are, and that's about 90% of you.
How about using two for stereo? That way you can tell which way the cannon balls are flying across your room during the 1812 overture. Most everybody says deep bass is non-directional, so you only need one subwoofer, and maybe it's the higher harmonics (or distortion) that gives the directional effect. But the believers in the "Wood" effect would say that phase matters. Which way is the candle flame (or your hair) blowing?
To see the real worlds most powerful subwoffer that works and is shipping go to www. and you can compare it to other subs at This 22" subs is 369 pounds and max spl is in the 155+ range. It only needs a 5 to 10 cf box and will hit 10 hz easy. It is also a lot less money. Only $7000.00 retail. Like it? You can have one!
p.s. My home sub-sub system uses four huge wooden 'tanks' in the attic above the top floor, one pressure and one vacuum per channel. Industrial chicken coop fans maintain pressure/vacuum, and hydraulic vanes control flow to the ductwork. The hydraulic pumps are way out in the garage. The noise is minimal but I have a whole floor separating the attic from the listening room, and the ducts are lined with acoustical foam. Fortunately the house is built with screws, not nails. I almost barfed once. And so far, only the dog has lost bowel control.
I did something like this for my master's thesis. I got down to 11hz and started pinging the frequencies of the foundation for the building. Inadvertantly I was also widening cracks within the existing foundation. So a cease and desist order was placed on my project until i could safely turn down the intensity level to not shake things to pieces..... -bix
You guys have it all wrong ...Here's what I understand from all this talk....thanks to the $13,000 from John at Wag End (he's a banker...) this tailrotor can save your marriage at 10 km, while explosive involuntary bowel movements will be minimal. Science Marches On!
A few folks have asked why bother below 20Hz, and others have responded that while we can't hear below 20Hz, we can feel it. I don't know the lower limit of human hearing, but one can certainly hear 16Hz at high enough pressure. This was demonstrated to me in Chicago when listening to five of Danley's Servodrive Contrabasses (incredible meeting of the Chicago section of the Audio Engineering Society, entitled "Where's the Bass", one of Dave Clark's people presented). The rule of thumb is 10dB: start with a bass frequency you can feel, if you then increase intensity 10dB, you can hear it. At this demo, we felt a recording of a door closing (8Hz in the recording), but we couldn't hear it.
I think we need to build one of these in our shop, just for fun. I have to believe that the inherent latency of this product would make it unusable for a home theatre situation. For pure musical playback, you can always delay the main speakers to be in correct time with the sub, but one would imagine that you are talking at least 50 miliseconds, so the sound versus the image would be way off. You would also want to band pass this thing so that it was not putting out anything above 30 cycles so that it would not mess anything that your main speakers were putting out. Phasing and time latency would be the killers for something like this in the real world. That being said, come on, you have to get one just to run 10hz through it; lets see if the Mythbusters can find the brown note with this thing! Now, for the rest of the world, the Sunfire subs are amazing for the price (under $2000.00) and if you really need to spend some money and you want to wow (read - annoy) the neighboors down the street, I will happily sell you some Meyer PSW-6's for around $14,000.00 a piece. We must salute the aboslute mad genius it took to come up with this.
I think that the military could have many uses for these things. From making prisoners literally spill their guts to knocking down a terrorist filled safe house, might even help take out land mines, endless uses ;-). The low freqs would make it hard for someone to determine where it is coming from. Would make it easy to disturb an evil neighbor and not get caught. With a few mounted on a car you could have fun setting off alarms blocks away, making people think that there is an earthquake, cops would be clueless where its coming from. Maybe this would be the ultimate mole deterrant. Vibrate the ground so bad that moles several houses away would leave to the next neighborhood. Oh I will have to build one. Looks like the standard RC helicopter main rotor may have all the features but not the mechanical strength to achieve the same results. - Luke
The MTX is just a gimmick for people who like to compensate for lack of sound quality. Have you noticed how all the specs on car subs are voice coil diameter and magnet size? Thats because the manufacturers dont like to admit that the key to good sound is in the details. The 22 is a piece compared to the TRW 17. Dont disrespect top of the line audio researchers over MTX.
If you whant a recording with a 1 hz tone than this is your thing: If you whant more information about the rotary woofer visit their website:
It is incredibly marvelos, though i haven't seen it i wuld definately get one.For long i had always wondered if there was sometin lik dis;i wuld surely get one.Its a dream come true 4 me.
Eminent Tech TRW 17 DAM!!!!!!!!! THIS SH%^ IS off the HOOK!!!! We just installed it and O MY LORD! The Fan acutely cuts the Sound waves and you can feel the Base, like you were watching an air show! My carbons and I bought the system after we raided a truck and sold all the goods Hot off the truck to Pepes Boys I got Laid on the 3rd day because this #^$^& was off the HOOK HOMES!