Have any of you guys checked out the Eminent Technology TRW 17?
http://www.eminent-tech.com/RWbrochure.htm
Seems like an interesting design for an infrasonic subwoofer.
Thoughts?
http://www.eminent-tech.com/RWbrochure.htm
Seems like an interesting design for an infrasonic subwoofer.
Thoughts?
Great, now we have something that can reproduce what?
"The amplifier should be capable of operating near its rated power at between 1 and 3 Hz."
Oh well, at least it will keep you cool while you are fuming over the $13K price tag I suppose.
Cal
"The amplifier should be capable of operating near its rated power at between 1 and 3 Hz."
Oh well, at least it will keep you cool while you are fuming over the $13K price tag I suppose.
Cal
Member
Joined 2003
It is specced as 1hz - 30hz +- 4 dB
I'm not sure it even qualifies as audio, but it might be just the ticket for movie effects...
I'm not sure it even qualifies as audio, but it might be just the ticket for movie effects...
Cost/benefit ratio way out of proportion here, unless someone can figure out how to clone it.
Most subwoofers' response falls off sharply below 20 hz (paraphrased from the website) - so what? Most human hearing does too! And so does most music.
As an HT sub it would be useful for creating vibrations, etc., but is that low freq information going to be in any recordings?
As primarily a music person, this thing is useless to me, and the price tag will lend itself only to those with money to burn. I don't think there are many of those on this forum.
My cynical 2 cents. 😀
Most subwoofers' response falls off sharply below 20 hz (paraphrased from the website) - so what? Most human hearing does too! And so does most music.
As an HT sub it would be useful for creating vibrations, etc., but is that low freq information going to be in any recordings?
As primarily a music person, this thing is useless to me, and the price tag will lend itself only to those with money to burn. I don't think there are many of those on this forum.
My cynical 2 cents. 😀
Thats what I want to know. If you check how it works, all it does is run the fan at a constant speed, and the driver just changes the angle of the blades thereby creating pressure waves. I'm sure theres a lot of tuning involved but can't a cheap concept model be made?
Hara said:
There has to be a fairly sophisticated mechanism to vary the pitch of the fan blades - similar to what a helicopter does.
The real question as far as I'm concerned is - who would really want this thing? Is it THAT big of a neato gadget? Is it worth anywhere near the price? A big fat no, I say. But if a cheap clone could be figured out, and it was for HT pretty much exclusively, AND if there was any recorded info in it's operating range, go for it I guess.
And don't forget to post the plans.
It's an interesting idea, but all the fans I know of that move lots of air quickly are noisy. How do they get round the wind noise problem?🙂
quote:
"We can now listen to never heard before very low frequencie sounds."
Now class, how many mistakes do you see in this sentence?
"We can now listen to never heard before very low frequencie sounds."
Now class, how many mistakes do you see in this sentence?
my ears go down to 2 hz psst
ive seen some other discussion elsewhere and it basically looks like its a traditional subwoofer voice coil/magnet assmebly that spins, and the voice coil changes the pitch of the blades, rather than moving a cone.
thats how i understood it worked. its purely mechanical and doesnt rely on electronics.
thats how i understood it worked. its purely mechanical and doesnt rely on electronics.
The motor on the site looks pretty beefy. Anyone have an idea of how fast that thing is turning? I guess with that much fan noise they really need to install it in a basement or attic.
And I second on posting pics.
And I second on posting pics.
its not THAT beefy. its probably like a 1/2 - 3/4 HP motor. its just a regular AC or DC motor from the looks of it. thats probably the cheap part. cheap for DIY i mean... you could pick up one of those on ebay for under $100. it doesnt even need to have much power, just as long as it can start spinning, thats all thats needed. it just needs to spin at a constant rate, there will be no different load once it gets going.
i forgot how fast it spins, but after talking about this with a few friends of mine (a few engineers), we came to the conclusion that the speed of the fan would probably determine to some extent the output power. the faster it spins, the more air its pushing, and the less the blades have to tilt. so, faster is better. however, the faster it goes, the more mechanical noise will be generated.
the mechanical noise (fan blade noise) is dealt with by redirecting the air through a tunnel or something so that the actual noise created by the fan is damped and diminished before the actual air gets to the room. for instance, at a demo, two adjoining rooms were used. in one room, the fan sat and had a duct system that ran to the doorway of the other room. the doorway was the baffle and fed the other room the "air" generated from the fan. therefore, the fan assembly was in the other room and the duct assembly isolated the sound of the fan from the actual listening area.
there has to be a better way, but its mechanical noise that will be there without question as long as the thing works like it does... so it just needs to be in another room or something. thats why on their site they show it in an attic. it is installed like an IB would be.
i forgot how fast it spins, but after talking about this with a few friends of mine (a few engineers), we came to the conclusion that the speed of the fan would probably determine to some extent the output power. the faster it spins, the more air its pushing, and the less the blades have to tilt. so, faster is better. however, the faster it goes, the more mechanical noise will be generated.
the mechanical noise (fan blade noise) is dealt with by redirecting the air through a tunnel or something so that the actual noise created by the fan is damped and diminished before the actual air gets to the room. for instance, at a demo, two adjoining rooms were used. in one room, the fan sat and had a duct system that ran to the doorway of the other room. the doorway was the baffle and fed the other room the "air" generated from the fan. therefore, the fan assembly was in the other room and the duct assembly isolated the sound of the fan from the actual listening area.
there has to be a better way, but its mechanical noise that will be there without question as long as the thing works like it does... so it just needs to be in another room or something. thats why on their site they show it in an attic. it is installed like an IB would be.
I would think that the load would vary a lot depending on the pitch of the blades at any given moment.
So I would think that it has to be powerful enough to withstand the sudden variations in pitch. I agree that motors such as you proposed should be plenty! That fan really isn't very big.
Variac said:
you are completely right. i forgot that there would be a load while pushing the air... to keep frequency response "flat" you would need a fan that would hold its speed regardless of pitch.
Well thats okay...
Still its alot of $ - as a few tempests will easily satisfy people to 18hz in room,is it worth it to get 3hz?
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