When does bass becomes inaudible?

[Thomas Kievit]

Interesting indeed xD

Instead of downtuning I prefer octavers/synths...

By the way, Interesting reading:

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Peace!

 

[T-Bird]

Hi.

^This.

Plain and simple.

If the SPL is below the curve at a given frequency, it'll be inaudible.
If it's above, it'll be audible. Obviously.

But, hey.....if someone's got a rig that can reproduce 17hz...........

With the exception of some transformer coupled amps or amps with extremely steep HPF's, we all have.

It's just the matter of the spl generated.

Unless one understands how easily the test will over-excurse and destroy a speaker, no-one should perform the very simple test that proves it.
All it takes is a 1/8" to 1/4" adapter or a cord and a laptop with an accurate signal generator.
And ones rig, obviously.

Regards
Sam

 

[InternetAlias]

Whoever wants to reproduce frequences below 40 should get a fan instead of a speaker.

 

[Duckwater]

Whoever wants to reproduce frequences below 40 should get a fan instead of a speaker.

I agree, if your goal is to be felt then these are perfect.

 

[InternetAlias]

The further problem is - once you are audible at frequencies that low you will have trouble playing inside, it's simply impossible not to hit some resonances once you go this low.

 

[Duckwater]

The further problem is - once you are audible at frequencies that low you will have trouble playing inside, it's simply impossible not to hit some resonances once you go this low.

Yep. One little venue that my band plays at weekly has a hollow and very resonant stage, it can't handle anything under 80hz or so without turning the entire stage sound into inaudible mush. I love super low frequencies, but I find problems with them anywhere but my home listening environment.

 

[Vince Klortho]

^This.

Plain and simple.

If the SPL is below the curve at a given frequency, it'll be inaudible. If it's above, it'll be audible. Obviously.

No, it's not that plain and simple. Did you notice that the curves are all rising from right to left at the left edge ? If it is as simple as you claim then the curve would fall off like a cliff right at 20Hz and I seriously doubt that it is the case. It is far more likely to have a steep roll off to the left of 20Hz but not a vertical cliff. Unfortunately there were no data points given below 20Hz on that graph. It is widely claimed that 20Hz is the lower limit of human hearing but that is primarily because of the difficulties in reproducing sound at that frequency and lower.

According to this page, "12Hz is the beginning of the aural range in laboratory conditions" and below that "Inaudible infrasonic sound waves can be felt by humans through physical body vibration in the range of 4 to 16 Hz."

 

[Vince Klortho]

As an aside, for some really good low frequency reproduction, check out servo drive subwoofers like [Invalid or Expired Link Removed] that is claimed to be accurate down to 12Hz. There is also this design :

It doesn't have a voice coil. It uses a servo-drive motor to move the cones. Those things go REALLY deep.

I used to have a custom-designed subwoofer with two JBL 18s that was tuned to 30Hz and a few RTAs verified that was where its F3 point was. I used a DBX 120XP subharmonic synthesizer with it and that was a lot of fun. It would generate frequencies below those present down to 24Hz and it would rock the house, literally. I used it in my home theater and it was terrific with movies and music both. I didn't know of Jauqo back then so my favorite piece of music to use with it was Bela Fleck and the Flecktone's song, "Flight of the Cosmic Hippo." (horrible video, sorry.) Victor played a fretless 5-string and there are some great sections on the B-string. When you hear those parts reproduced really solidly it is just awesome. It is music that becomes tactile as well as audible. Unfortunately, that subwoofer was the size of a refrigerator and my wife wouldn't let me take it with us when we moved.

 

[T-Bird]

Hi.

No, it's not that plain and simple.

For me as an engineer it sure is.

Did you notice that the curves are all rising from right to left at the left edge ? If it is as simple as you claim then the curve would fall off like a cliff right at 20Hz and I seriously doubt that it is the case. It is far more likely to have a steep roll off to the left of 20Hz but not a vertical cliff.

???

IOW, the lower the frequency below 20 Hz, the lower the hearing threshold?

Very unlikely.

In engineering and in other applied sciences, extrapolating is a common necessity. The data provided may be limited with the accuracy equipment, or the repeatability of the measurement, or something else, but in a real world situation the *"ball-park" figures of extrapolation are good enough.

It is widely claimed that 20Hz is the lower limit of human hearing but that is primarily because of the difficulties in reproducing sound at that frequency and lower.

Depends on the allowed distortion and allowed structure generated harmonics.

Most amps can somewhat control and amplify down to a few herz, some into the fraction of a herz before starting to modulate, it's the speaker that can't keep up. And that "not keeping up" generates the distortion and harmonics that makes a clean job difficult.

Any motor driven crank assembly attached to a piston of some sorts will be able to go as low (/slow) as needed, but the impedance mismatch between the moving assembly and air will limit the frequency that can be cleanly generated.

Regards
Sam

 

[Vince Klortho]

For me as an engineer it sure is.

I am an engineer too and I am embarrassed to admit that I misinterpreted the graph and your point but I try to admit my mistakes. You are right. If one were to extrapolate, as you mentioned, the curve would likely continue rising to the left.

BTW - I have heard (and felt) one of those servo-drive systems. The bass was truly tactile that night. I watched the sound guy punch in a DBX 120XP periodically and it was very cool !