# Can a sub goes to low?



## daniel (Dec 31, 2006)

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.


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## drdoan (Aug 30, 2006)

LOW, LOUD, CLEAN, the only way to go. Dennis


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## tonyvdb (Sep 5, 2007)

Your going to find it tough to find a sub that will go below 15Hz at any decent db's but theoretically the lower the better there are lots of things in the real world that can produce frequencies even lower, Thunder for example or a sonic boom from a jet can defiantly hit frequencies in the single digits. 
The so called muddy frequencies are usually in the higher octaves between 200 and 40Hz. this can be corrected by proper acoustics and bass trapping.


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## bobgpsr (Apr 20, 2006)

Tough to buy a single hi output @ 15 Hz sub. Not so hard to build -- ala Steve Callas LLT. :T

Multiple sealed 18" subs with eq will also do it. Or those nice multiple 18" driver Infinite Baffle DIY installations.

If you have the space.


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## imbeaujp (Oct 20, 2007)

The question : Is that frequency range (5 to 15 hz) present in the source you are listening to ?

Some movies use verry low frequency but I think that is not the case with many CD.

Am I right, please correct me.


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## tonyvdb (Sep 5, 2007)

Not in most CD's but I know of a few one in particular by Telarc that was recorded at least 15 years ago that has a warning on the front saying to turn down your system and test first as there were digital cannons that had frequencies in the subsonic range that would cause damage to speakers if played to loud.
Telarc is well known for there dynamic digital recordings that will tax any system.
ALot of newer recordings done in a studio will have tracks that have a wide dynamic range including stuff in the 15hz and above range. GRP records also does some really good recordings on CD.


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## bobgpsr (Apr 20, 2006)

imbeaujp said:


> Some movies use very low frequency but I think that is not the case with many CD.


I have a DVD-A of Saint-Saëns, the Symphony No. 3 "Organ", that pushes some über low floor vibrating notes. For the deep notes, wait for after the overall 27 minute mark, during Part II (~8 minutes into it). 

Of course pipe organ music can be an entirely different scenario for music lovers and the need for subwoofers that can reach down really deep.


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## ISLAND1000 (May 2, 2007)

"Can a sub goes to low" ? No, let the sub play as low as it can without the cone falling off.


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## mazersteven (Apr 5, 2007)

daniel said:


> 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.
> ...


I want a sub that it Tight, Accurate, and goes Sub-Sonic without distortion or sounding boomy. I also want it to have enough headroom for it's environment.


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## SQBubble (Nov 12, 2007)

the lower you go, the more air you have to move, multiple driver or a/some high excursion subs are needed to have the best result.


Also, just want to add, theres a big percussion construction machinery that produce some very, very incredible low-frequency sound at loud volume. Was literally shaking the road and had to speak louder than usual to have a conversation. I was really surprised!


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## imbeaujp (Oct 20, 2007)

Everybody knows that 2 way or 3 way speakers are a good concept because each drivers performs on a specific range. In the sub woofer domain, is this concept apply ? Would it be more efficient to have a specific sub to address the 5 to 30 hz range and another for the 30-100 ?

JP


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## bobgpsr (Apr 20, 2006)

imbeaujp said:


> Everybody knows that 2 way or 3 way speakers are a good concept because each drivers performs on a specific range. In the sub woofer domain, is this concept apply ? Would it be more efficient to have a specific sub to address the 5 to 30 hz range and another for the 30-100 ?


Just likely would quite expensive and it is rarely done. The 30 Hz crossover should be done, IMHO, at line level with power amplifiers afterwards. You would have to do that crossover yourself since AVR/Pre-Pro's do not -- although some can be adjusted to do the sub crossover as low as 40 Hz.

Better (more practical) to use (set to LARGE) big 3-way L/R full range mains that have 12" woofers that are rated to -3 dB @ 30 Hz (full power) and use the extra low range sub crossed at 40 Hz.

The problem with that is that the LFE channel is supposed to supply sound from the lowest freqs (5 Hz?) to a normal high end freq of 120 Hz.


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## conchyjoe7 (Aug 28, 2007)

I have heard that "Telarc" disc and the warning is valid. It has been a very long time, but if I remember correctly, it has the "1812 Overture" on it and the cannon blasts are what the warning is about.

Cheers,
Konky.


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## rotfan (Feb 19, 2011)

Lower the better. Telarc CD-80437 The Big Picture Cuts #6 & 7 The Apollo 13
Mission and re-entry The bass response is below 5 hz and will destroy conventional
subwoofers. The only subwoofer that can handle this recording with authority, low
distortion and realism is the Eminent Technology TRW-17 Rotary subwoofer. When I
play this recording the doors in my room move back and forth .5" The Rotary subwoofer
goes down to below 1 hz without stress or compression and one does not have to worry
about destroying it.


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## tonyvdb (Sep 5, 2007)

rotfan said:


> The Rotary subwoofer
> goes down to below 1 hz without stress or compression and one does not have to worry
> about destroying it.


Hmmm not sure about that. 4Hz is just about impossible to reach or reproduce 1Hz not possible.


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## rotfan (Feb 19, 2011)

Yes, the rotary woofer goes down to below 1hz Go to 
Eminent Technology's web site and see for yourself!!!!!!!!


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## vann_d (Apr 7, 2009)

yes, this is the new big thing supposedly...the big air moving fan. Seems pretty cool and people are already trying to diy it


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## robbo266317 (Sep 22, 2008)

I purchased the Telarc 1812 on vynil when it first came out and you need a top end turntable to play it on as the canon fundamentals (3 Hz) jump sideways about 3/16". You wouldn't play it loud on a ported sub unless you could afford new drivers. :spend:


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## Andre (Feb 15, 2010)

Too tell the truth I have never understood this, for the following reasons as examples

a. An Oppo BDP-83's frequency response is 20hz - 20khz
b. A high end AVR such as the Denon 5308 has a frequency response of 20-20k
c. human hearing (when we were young and unbroken) 20-20k

You can't play what the source isn't producing.

Under 20hz I believe you Feel rather then Hear. This to me involves:

Pressure: You feel the air move in the room, bigger rooms require bigger subs to pressurize them to acheive this effect.

Vibration: Some like it, some don't. IF this is something that enhances the experience for you, consider adding a tactile transducer to your system.


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## koyaan (Mar 2, 2010)

I've often mused over the same thing. Most equipment isn't designed to reproduce anything below 20hz, yet they seem to do it. My BDP-83 SE feeding an Outlaw 990 will produce sound so low you can't hear it, but you feel like a truck just ran into the house.
My biggest sub ( Outlaw LFM-1EX ) only goes down to @ 15hz. I've never found that too low. I guess it can't sound muddy if it's too deep to hear.


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## rotfan (Feb 19, 2011)

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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## rotfan (Feb 19, 2011)

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
believing!!!!!!


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## vann_d (Apr 7, 2009)

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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## Andre (Feb 15, 2010)

Koyaan:
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


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## rotfan (Feb 19, 2011)

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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## Andre (Feb 15, 2010)

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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## rotfan (Feb 19, 2011)

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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## tonyvdb (Sep 5, 2007)

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.


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## rotfan (Feb 19, 2011)

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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## sfdoddsy (Oct 18, 2007)

daniel said:


> 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.
> ...


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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## lsiberian (Mar 24, 2009)

I don't know of a chamber capable of preventing noise pollution below 20hz, so forgive us for not entirely buying the measurements. I have no doubt a rotary sub can produce extremely low bass though. But I would think you get all sorts of pollution in the master on the low end.


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## rotfan (Feb 19, 2011)

I not sure what you mean when you talk about noise pollution. Are you familiar 
with Peter Moncrieff of International Audio Review. In his review of the rotary subwoofer
he has measured the performance of the rotary subwoofer using many different
tests and has said that it has response down to below 1 hz. The frequency plot
was made by Bruce Thigpen of Eminent Technology and he also has distortion
measurements as well. I have been reading Peter Moncrieffs reviews for many
years and found him to be the most reliable audio reviewer. All his reviews were
backed up with scientific methods and without this article on the rotary subwoofer
I would not have purchased it. I wish you were close to where I live so I could
give you a demonstration of the rotary subwoofer; once again, it's awesome. Thankyou


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## hgoed (Mar 22, 2010)

I can only share one experience, and it was admittedly a while ago, but was very formative in my opinion:

The only time I remember experiencing such sub-sonic frequency, was in a little theater in Seattle. They were showing James Bond, I think it was GoldenEye (and I don't know what audio information/mix they were using). I remember it because I sat next to Bill Gates and his relatively new bride. After the movie we both looked at each other and said "not again" --I think he saw me shifting uncomfortably. It was just too much. 

Anyway, some things are awesome to think about, but are really not that fun to experience. That's just my opinion.


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## rotfan (Feb 19, 2011)

Like most live events and theaters around the country, the sound is way too loud!!!!!!!
I do not go to any live events or theaters anymore, because of the excessive levels and
unbalanced sound. One example, many years ago in Las Vegas, my wife and I
saw a show, and the sound level was so high, that we both walked out. The levels
that I use are very comfortable and the rotary subwoofer adds greatly to the 
excitement and realism. A "true indication" of a quality sound system is being
able to listen at lower levels. Having a system with very low distortion, spacious,
detailed, bass that is tight with great impact, imaging, excellent high frequency
response, and enjoyable, is what I strive for. The reasons that a lot of people play their systems so loud are (1) poor acoustics) (2) speakers that can't resolve low level detail
(3) out of balance of the entire frequency range. (4) one's ears become less sensitive
the lower the frequency range. Getting one's system to sound great at lower listening
levels, yet still provides excitement, takes a lot, but, it is the answer to a rewarding
experience. Also having surround sound that gives one the feeling of "great space", 
helps a great deal in keeping levels lower, yet very pleasing to the ear. I have had
many people over to listen to my system and everyone told me that it sounded
very real at the levels that I use. When used properly, the rotary woofer is exciting
and adds a lot to the overall experience.


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