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Old 12th February 2013, 02:38 PM   #34911
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Default Surround Sound...

Tap test is in one direction.
Hi Q resonance can be excited to high amplitude by sustained acoustic excitation.
Tap test is short duration.

Dan.
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Old 12th February 2013, 02:46 PM   #34912
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Nope, not even close.
Right.
Thats all the difference if you hit a guitar chord (or body, or a snare drum), or if you look for sustain or Larsen with high spl. It is, indeed, not a matter of level, its a matter of acceleration.
The mechanical excitation will produce a huge higher peak and it is not frequency dependent.
Same way a fast rising edge square wave will excite any resonance peak in the bandwidth of an amp.
Max, you can believe-us, it is experienced.
Duration is not a matter, and you can hit in the 3 dimensions if you fear, while it is not necessary.
Keep-it simple.
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Last edited by Esperado; 12th February 2013 at 02:51 PM.
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Old 12th February 2013, 02:46 PM   #34913
1audio is offline 1audio  United States
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If you are convinced your hardware is vibration proof, try moving it to the next room except the speakers and listen.

Having the stuff between the speakers really messes with the acoustics of the room but we must have the shrine.

I used to do a demo- pair of Quads in a room pretty clear of stuff with damped walls and a carpet. Put a record album on the floor between the speakers (lowest output angle for Quads) and everyone heard the significant change to the sound, not a good change either.
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Old 12th February 2013, 02:56 PM   #34914
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Put a record album on the floor between the speakers (lowest output angle for Quads) and everyone heard the significant change to the sound, not a good change either.
A turntable is a microphone !!!!! Designed to transform any mechanical vibration in signal !!!!
We are talking of electronic devices. *Except transports*. Were-we not clear enough ?
Even a CD player can be sensible to vibrations, because they change the relative position of the lens and the record, and so can create errors due to unfocus or unexpected move of the head out of the groove. Of course hundred times less than a PU head. Just reading's errors, no creation of signal ! Hit your turntable, you hear-it loud. Hit your CD Player, no sound, but you can see errors correction changes, jump of frames, or event music can stop.
Hit your USB key, your SSD, your preamp, your DAC, your power amp : nothing.
It is SOOO simple to understand.
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Last edited by Esperado; 12th February 2013 at 03:16 PM.
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Old 12th February 2013, 03:11 PM   #34915
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if it was a promotional event they were probably flogging the momentum
But John said "(very expensive)." The Momentums are only $350, a bit more than $1,000 less than the HD-800's. So if not the HD-800's, maybe the 700's.

Or maybe John considers $350 to be "very expensive" for a headphone.

By the way, I've a pair of HD-800's here and find them to be a bit on the "extra crispy" side at the top end. Though maybe that's because I'm used to my LCD-2's.

se
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Old 12th February 2013, 03:12 PM   #34916
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Dan, you do understand that a tap (impulse) excites at all frequencies, right?

Demian, so true! It's not so much the vibration (some tube gear excepted), it's the diffraction.
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Old 12th February 2013, 03:14 PM   #34917
SY is offline SY  United States
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Or maybe John considers $350 to be "very expensive" for a headphone.
If so, I'm with John. I spent a couple of days with an array of hideously expensive headphones, and while they were very nice, at the end of the day, they were... headphones.
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Old 12th February 2013, 03:16 PM   #34918
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If you want to show how 'essential' are special feet or astonishingly rigid chassis then the best way to do this is to ensure that your circuit contains a follower which is oscillating at some VHF frequency. RF oscillators are always very sensitive to movement.

This technique works best if you don't realise that your circuit contains such an oscillator, so don't check for it. The best way to avoid checking for it is to remain ignorant of RF so you don't know how to check for it and don't even think you ought to.
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Old 12th February 2013, 03:18 PM   #34919
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If so, I'm with John. I spent a couple of days with an array of hideously expensive headphones, and while they were very nice, at the end of the day, they were... headphones.
True enough. I'll take my old Pioneer CS-99A's over any headphone.

se
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Old 12th February 2013, 03:22 PM   #34920
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If you want to show how 'essential' are special feet or astonishingly rigid chassis then the best way to do this is to ensure that your circuit contains a follower which is oscillating at some VHF frequency. RF oscillators are always very sensitive to movement.
Right, and i have pontificated at it. If your preamp or amp is oscillating, it is a *failure*.
Fix the electronic, not the chassis.
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Last edited by Esperado; 12th February 2013 at 03:26 PM.
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