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Author Topic: CSDs for four different iterations of LCD3 - from most veiled to least veiled  (Read 7695 times)

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Marvey

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Attached are four LCD3 CSD plots in succession from least subjectively veiled to most veiled. most veiled to least veiled. Note the ringing on these measurements has been exaggerated. (These are open air measurements. Sealed measurements, which are more reflective of what we actually hear, results in the ringing reduced to below -25db. This phenomenon seems to be an ortho effect does not apply to dynamics.)

I don't know what can be arrived at these measurements other than the faster and clearer sounding iterations have the resonance at higher frequencies. Could it be greater tensioning of the diaphragm? [More experiments on this later.]

The first plot was of an LCD3 which was obviously veiled. The second LCD3 also sounded quite veiled, but not as much as the first one. The last two plots were un-veiled LCD3s with one sounding just ever so slightly faster than the other.
« Last Edit: March 05, 2013, 11:41:14 PM by purrin »
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gurubhai

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Nice work purrin.

It certainly seems like they increased the diaphragm tension.Eagerly awaiting further experiments. :)
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Marvey

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Thanks. You are the one who actually gave me the idea on this (your post on HC.) I figured resonances shift up when tension is increased (like a guitar string). So I went back and looked at the data I had. This would seem to support your hypothesis.
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maverickronin

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You guys are pretty good, figuring out what the problem in the QC was.

What does that ringing actually sound like?  Even at -25dB it would look pretty scary to me.
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gurubhai

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Thanks. You are the one who actually gave me the idea on this (your post on HC.) I figured resonances shift up when tension is increased (like a guitar string). So I went back and looked at the data I had. This would seem to support your hypothesis.
Your impressions were detailed enough to make an educated guess.

Actually we had discussed the Audeze QC issues on ortho thread at HF & it was Wualta who suggested the 'driver tension' might be an issue.
He also said that the thinner the diaphragm, the more difficult it is to get consistent tension across drivers. Fits well with the fact that audeze ran into trouble with the new, thinner diaphragms of LCD3.
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rhythmdevils

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It's good to have professional orthodynamicists over here.  :-)
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grev

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Great diagnosis!
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dBel84

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Have been mulling a way to be able to test this, anyone here an optometrist or ophthalmologist or perhaps knows one well enough to humour some strange antics with their glaucoma measurement equipment.

This tool , blows a small puff of air against the cornea and thus measures the pressure in the globe = this would be one way to get reliable comparative data. I am sure there are other tools too but I am not familiar with any of them. The air could be blown through the front of the driver assembly - assuming that the magnets are all equally spaced from the membrane.

..dB

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gurubhai

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^ Don't think that would work, Don.
NC tonometer are based on the assumption that corneal surface is convex. The 'air puff' flattens the corneal surface & the time taken to do this flattening gives us the ocular tension. Its unlikely to work on a planar surface.
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Valentin Hogea

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Marv!


Do you have any closed measurements of a "good" LCD-3 (except for the "old style" plots I've found)?


Thx,
V
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