Quote:
Originally Posted by Marik  Hi Andy,
I am not sure if I understand why would you want to get a single Hz range tuning--it is the same as to make a half pound woofer cone. Sure it will go quite low, but it'd just inefficiently flip around without giving any useful sonic information.
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Actually, the tension makes little effective difference to the efficiency of a ribbon microphone (above the resonant frequency) - unless you count resonance as efficiency.
We want the resonant frequency as low as possible to keep the audible band free of resonance.
Also, comparing woofer mass to ribbon tension doesn't make sense.
We don't change ribbon
mass for tuning, we reduce
tension. Hence the corrugations.
Quote:
I am not sure what it is all about, as I find it very strange generalization.
First, why is that all short ribbons DO NEED damping? and
Second, WHY the long ribbons damping are left to taste or application? I'd feel it is rather a means of improvement of technical and sonic characteristics and would depend largely on some specific design choices.
Best, M
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Leaving 'piston' designs out of the question for the sake of simplicity -
Short ribbons need damping because they cannot hold a low enough tension to keep their self resonance in the sub-sonic range. Since their self resonance is usually in the very audible lower/upper bass or even mid range, friction damping is used to 'reduce' the problems in those ranges.
With long ribbons, since low tuning can be used to set the self-resonance frequency to a sub-sonic range, the issue of damping becomes a safety, headroom & application issue.
You can use a transformer which doesn't pass sound that low, or you can friction damp or you can leave it alone and hope the user knows what he is doing!
Andy