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What Is the Real Lowest Audible Frequency & Best Subs to Achieve It?

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Bob Somers:
I've seen all sorts of statements about what the lowest audible frequency by humans is and also, if there is a min SPL needed for it to be audible that is unusually high (such as 110dB, for example), please let me know what that value is.

I would greatly value your observations on this from your own direct listening/measurements experience.

Also, if there are any well regarded academic research sources relating to this, a pointer to them would be great.

I have a second question.

For a home living room, say dimensions approximately 15' X 15' X 8'(height), which subwoofer (including those now available and also those that have been discontinued) or subwoofer combination (and if more than one of these is needed, please say so) would cover 125Hz down to the lowest audible frequency at say, +/- 3dB all at whatever the max SPL level is that the human ear can tolerate without pain (this may be about 120dB, not sure and may vary with frequency) and with inaudible distortion or if that is not achievable, then with the lowest currently available.

Of course, there are tradeoffs among the above criteria and I'm interested in your opinion on what equipment would give the most desirable results.


Please include these in what you consider if you have knowledge of their performance: labsub, submersive, contrabass, basstech 7, whatever the current most potent model is of the Danley Tapped Horn design, Thigpen Rotary Woofer (a fan with variable pitch blades), Paradigm Sub 2, and a real oldie: the Bose Acoustic Cannon.


Thank you very much!!!

James Feenstra:
nothing that will fit comfortably (that I know of) in a living room will go down to 18-20hz @ 120db

I guess if you felt like making a table (that you couldn't put anything on) out of a sub you could go with something like an adamson t21 w/ a lab gruppen fp7000 or equivilant

be prepared to spend $10,000+ PER SUB

one would probably do that kind of volume at that distance, or it'd kill you, one of the two

Ivan Beaver:
Quite a few use these and some even 2 and 3 in their rooms  

http://www.danleysoundlabs.com/tapped_horn.asp?MODEL=DTS 10

For different size:

http://www.danleysoundlabs.com/tapped_horn.asp?MODEL=DTS 20

And the slim version:

http://www.danleysoundlabs.com/tapped_horn.asp?MODEL=TH SPUD

It is hard to distinguish between what you are hearing and what you are feeling at those freq.

But the louder it is, the lower you can hear it.

And at the lowest freq, are you hearing it or experiencing atmospheric pressure changes?

Art Welter:
Bob Somers wrote on Sun, 23 January 2011 21:22
I've seen all sorts of statements about what the lowest audible frequency by humans is and also, if there is a min SPL needed for it to be audible that is unusually high (such as 110dB, for example), please let me know what that value is.

I would greatly value your observations on this from your own direct listening/measurements experience.

Also, if there are any well regarded academic research sources relating to this, a pointer to them would be great.

I have a second question.

For a home living room, say dimensions approximately 15' X 15' X 8'(height), which subwoofer (including those now available and also those that have been discontinued) or subwoofer combination (and if more than one of these is needed, please say so) would cover 125Hz down to the lowest audible frequency at say, +/- 3dB all at whatever the max SPL level is that the human ear can tolerate without pain (this may be about 120dB, not sure and may vary with frequency) and with inaudible distortion or if that is not achievable, then with the lowest currently available.

Of course, there are tradeoffs among the above criteria and I'm interested in your opinion on what equipment would give the most desirable results.

Please include these in what you consider if you have knowledge of their performance: labsub, submersive, contrabass, basstech 7, whatever the current most potent model is of the Danley Tapped Horn design, Thigpen Rotary Woofer (a fan with variable pitch blades), Paradigm Sub 2, and a real oldie: the Bose Acoustic Cannon.

Thank you very much!!!



The Bose acoustic cannon, at about 106 dB at 25 Hz, does not qualify as a real contender in today's VLF arena. The 150 inch length is a bit of a problem too .

If you were to extend the lines to lower frequencies on the ISO 226 chart you would have a good idea of how loud low frequency needs to be audible at a particular level, and to be heard at equal loudness levels.



That said, there is another aspect to VLF hearing that is not often understood, at around 1000 Hz, a 10 dB change appears to be twice (or half) as loud, while at 20 HZ +5 dB appears twice as loud.
Because of this, and peoples perception, a slight increase in very low frequencies, or infrasound, can be annoying to one person and imperceptible to another.

I know I can hear idling trucks and generator VLF noise at SPL levels the chart says are below the minimum level. Wish I could say the same about my hearing response at 4K and above 15 K   .

The levels required to damage hearing at very low frequencies are extreme, pretty much beyond the capability of any present transducers that could be fit in a room. Astronauts are subjected to over 160 dB of VLF on takeoff with no apparent hearing loss, there are no loudspeakers approaching that level at VLF.

One thing to watch out for is the tendency to turn up the volume when you have plenty of low, clean bottom.

Headphones are the cheapest way to experience low frequencies down into the single digits, and without the coloration a room adds. A 20 Hz wave is over 56 feet long, so even in a good sized room it will reflect off the walls, floor and ceiling many times.

The DSL tapped horns are probably the most efficient VLF loudspeakers, and can provide serious level in the large units.
Their disadvantage is size, and they require DSP for optimum integration due to the long path length.

There are plenty of subs capable of low 20s and even single digit performance that are plenty loud enough to be heard and felt that are not huge, though they use more power to achieve the level.

I use a Mackie HRS 120 in my control room, placed in a corner it is “flat” (other than the huge dips and peaks caused by the small room dimensions) to below 20 Hz. The size is only 18 x 19 x 21 inches, but it produces enough LF output to excite wall resonant frequencies as low as 15 Hz.
It is interesting to hear a wall flapping when “scrubbing” a tape (well, actually, scrubbing a hard drive).
It is rated at 117 dB maximum SPL at one meter, which it probably can exceed in a corner of a small room. It has no problem keeping up with a pair of Tannoy PBM 6.5, small near field monitors.
I purchased it used after listening to several other small studio monitor subs, it was the only one that I heard that had much out put below 30 Hz.

A pair in a small room should allow 123 dB peaks down to 20 Hz, which would “keep up” to 80 dB at 1K. In music, that level disparity is not "normal", few forms of music (other than some electronic dance music) actually have 20 Hz levels recorded louder than the 60-120 Hz range.

I was also quite surprised by the Carver Sunfire, which can get down to 18 Hz in less than one cubic foot, though it’s not as loud as the HRS 120, even though it uses more than four times the power.

Most  “good”  PA subs are dropping at 24 dB per octave at around 40 Hz, so the output these little buggers have exceeds many full sized 2 x18” cabs at 20 Hz.

Art Welter

Jonathan 'JP' Peirce:
I was pretty impressed by the Meyer X-800...
JP

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