Tweakers' Asylum

RE: "…I think vibrations of low frequency are not as damaging…as vibrations of high frequency"

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In Reply to: RE: "…I think vibrations of low frequency are not as damaging…as vibrations of high frequency" posted by Kirill on April 26, 2010 at 09:06:35

I think you need to think again, especially about slowing deceleration time. That means that vibration sustains longer and if you do that, it starts to "fill in the gaps" or silences between notes and legato bass passages become less clear.

As for little musical content below 40 Hz, think again also. While the lowest note on the standard electric bass/double bass is approx 41 Hz, the piano extends down to 29 Hz and several brass instruments extend lower still so sub-40 Hz content may well be found on any music with a piano involved and even sub-30 Hz content can be found on orchestral recordings. Organ recordings can go even lower and I once saw a listing of organ recordings with low bass including one CD containing 8 Hz tones. Once we start moving to a lot of more modern music styles involving synthesisers, you can also get a lot of very low content.

Apart from that, a lot of the "spatial" sound of live venues can contain content down to extremely low frequencies simply because of the size of the spaces and the frequency of the fundamental modes. Even if the music being played may not contain much below 40 Hz, subharmonic resonances can be excited in the space and contribute to the "feel" of the recorded acoustic.

Room size also does not place a limit on the lowest notes that can be produced in a room. The lowest room mode represents the lowest frequency at which the room will resonate, not the lowest tone that the room will support. If you couldn't get low frequencies in small spaces you would not hear bass in a car and subwoofers would have no effect in cars. In actual fact, closed rooms can actually support and boost bass response at frequencies below the room's lowest modal frequency which is one reason why small speakers can sometimes provide better bass than expected in a small room. While the speaker may be rolling off below the lowest fundamental mode in the room, the room's added support at those frequencies can boost the bass that is there and ensure that it remains audible to a lower frequency than expected.

Frankly, I think low frequency content is a little bit more common than you think, and speaker performance at low frequency can also be better than expected under some fairly normal home circumstances, giving much more extended response than suggested by the speaker's specifications which are normally anechoic measurements.

Vibration control in audio isn't about preventing materials from breaking, but about reducing their vibration and reducing the audible sonic colouration that can occur as a result of that vibration.

Do what you like but I will repeat my comment that until you've heard the same system both with and without good vibration control extending down to below the lowest octave, you really have no idea of how much vibration at those frequencies can affect things.

David Aiken

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