Can a sub goes to low? - Page 3 - Home Theater Forum and Systems -

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post #21 of 34 Old 02-23-11, 03:47 PM
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Re: Can a sub goes to low?

The following frequency response graph shows the response of the rotary subwoofer in
typical installations.
I use a PS Audio Perfect Wave DAC (this dac is dc coupled, with no capacitors limiting
very low bass response.) Winston Wright of Eminent Technology measured the response
in my room utilizing a test cd and the frequency response was close to this same frequency plot.

The Rotary subwoofer controller, which pitches the blades, designed by Marchand
Electronics for Eminent Technology, has the required very low frequency response also.

In order to "hear" 10 hz you need sound pressure levels above 100 db. To "hear" 5 hz
you need sound levels above 110 db. I have had several audiophiles over for a demo and
every one "heard" these test tones down to these frequencies. Conventional subwoofers can
not produce the necessary acoustic levels required to hear these very low sounds. There
are many movies on blueray that benefit from the rotary subwoofer. A audiophile friend
of mine contacted an engineer at Oppo and asked him what the very low frequency capabilities of the blueray players were. While the specifications in the user manual state
the response down to 20 hz,there is significant very low frequency response below that.
Quality microphones have extremely good very low frequency also. Until you have heard
this rotary subwoofer you can not experience what I and many others have. This gives
one the most realistic and exciting very low bass reproduction available.
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post #22 of 34 Old 02-23-11, 03:55 PM
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Re: Can a sub goes to low?

Tactile transducers just vibrate and do not push air to produce sound. There is no
comparison between these transducers and the rotary subwoofer. Hearing is
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post #23 of 34 Old 02-23-11, 03:57 PM
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Yeah, just because a device is specified for 20-20000 Hz doesn't mean it won't produce frequencies outside this range.

That rotary woofer is pretty sweet. I heard a number somewhere that the cost is around $15k. Is that about right?
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post #24 of 34 Old 02-23-11, 03:59 PM
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Re: Can a sub goes to low?

I rest my case. You didn't hear any sound, you felt the pressure of the sub moving the air in the room. The room shake is mechanical, you jumping up and down in a room would be felt as vibrations to others, the vibration of the subs enclosure is interacting with the surface it is coupled too and that surface is coupled to other..etc.etc, however it will be less noticeable further away from the source

Rotran and Van: I am happy for your joy of the subwoofer fan. Koyaan if you can afford said equipment (I certainly cannot) you may be very happy.

Rotran: I never said a transucer would produce sound

Last edited by Andre; 02-23-11 at 04:07 PM.
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post #25 of 34 Old 02-23-11, 04:13 PM
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Re: Can a sub goes to low?

Yes, with the necessary motor controller, rotary woofer controller, xover, the cost
is about 15k. When one considers the time (5 years of development, materials,
testing and long term reliability, not to mention profit, the cost, is in my opinion about
right. The rotary subwoofer requires no maintenance and will stand up to extremely
high output levels. Check out the Niagara Falls installation, where Eminent Technology has
put 6 rotary subwoofers to immolate the sound of the falling water. If one does not
build the necessary enclosure for this rotary subwoofer and has Eminent Technology
build and install, test, the cost goes above 20k.
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post #26 of 34 Old 02-23-11, 04:17 PM
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Re: Can a sub goes to low?

I simply could not justify the cost in a Home Theater, Commericial applications would be very nice to hear and feel. I stand by my opinion written above for old pensioners like me.
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post #27 of 34 Old 02-23-11, 04:35 PM
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Re: Can a sub goes to low?

Please call Bruce Thigpen of Eminent Technology and ask him about the ability to hear below 10 hz and lower with the rotary subwoofer. I would be happy to give anyone
a demo of this rotary subwoofer, and this would convince the skeptics. Also, please
read Peter Moncrieffs extensive review of the rotary woofer in "The International
Review, titled "The Only Subwoofer. Peter Moncrieff has been a audio reviewer for
many years and uses scientific proof to back up his findings. In this long article it
explains the ability of humans to hear down to very low frequencies.
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post #28 of 34 Old 02-23-11, 04:45 PM
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Re: Can a sub goes to low?

Weather or not those readings are actual readings or not that still dose nothing to prove that they play below 5Hz as I cant think of any real world applications where it would be necessary to go below 8Hz or for that matter have recordings on BlyRay that go that low. Anything below 8Hz is basically pointless.

Home theater:
Onkyo 805, Yamaha YDP2006EQ, Samson Servo 600 amp
3 EV Sentry 500 monitors across the front, 4 Mission 762i's Surrounds, SVS PB13U sub, Panasonic BDT220, Harmony 1100, Nintendo WiiU
Panasonic PT-AE8000 on a 120" 2,35:1 fixed screen

Living room system:
Sherwood/Newcastle R972, Mission 765's, SVS SBS02's, A/D/S MS3u sub, Yamaha YDG2030EQ
Yamaha KX-393 Tape deck, CDC 805 CD changer, Panasonic BD60, Sony turntable PS-T20
Panasonic TC-P50ST60, HD-PVR & WDTV Live, Harmony 900

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post #29 of 34 Old 02-23-11, 05:40 PM
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Re: Can a sub goes to low?

Tonyvdb: Here are a few more examples of recordings and movies with very low content.

Tchaikovsky 1812 (cannon shots way below 5 hz) Telarc CD-80541
Symphonic Star Trek (many sound effects below 10 hz Telarc CD-80383
Surround Sounds (T-Rex Dinosaur foot stomps, electronically generated 3-5 hz)

Thunder claps (way below 5 hz)

Lord of the Rings (many very low sound effects)
War of the Worlds (incredible low frequency energy)

It is not pointless when one is seeking realism. The point of a great home theater
is to give one the most exciting video and audio experience. This is what I am seeking,
if not, I would just watch tv on a small monitor with tiny speakers.
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post #30 of 34 Old 02-25-11, 11:42 AM
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daniel wrote:
I know there's different schools regarding subwoofer.
Some say "go as low as you can".

Other argues that if it reproduce a to low frequency, it will overload the room and muddy the sound.

But that last few hz are very tempting!

What is your personal experience.
This is incorrect. 'Overloading' is usually considered to happen when a sub hits a nasty room resonance.

However, once you get below a certain frequency you no longer excite room nodes. This frequency varies with room size ( the bigger the room the lower the frequency) but is why car bass can go so low so cleanly. The smaller space of a car raises the frequency of the lowest room mode, so everything below that is relatively smooth.

Of course, as mentioned above, to actually produce reasonable output down low is not easy. The excursions required increase exponentially.

Having said that, i am one of those who goes for the last few Hz. I like organ music. My mains are flat to 20hz at reasonable volumes, and my sub is flat down to 16hz at higher levels, but it takes some serious EQ and amp power even though I don't listen loud.

I have the Telarc CD mentioned above and it is not playable in my system at even average levels due to the low frequency transient of the cannon shots. There is another Telarc CD, the DTS Surround Sampler, that is even worse. The opening sound on the opening track starts at 8hz or so and is silent until you see your drivers flapping
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