Grease to Lower Speaker Q - diyAudio
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Old 27th July 2005, 07:28 AM   #1
Badeck is offline Badeck  Philippines
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Exclamation Grease to Lower Speaker Q

Hi, I am new to this forum.

I joined to know and share ideas about sound box design.

I am currently designing a vented box for the fronts of my PC (5.1 channels). With the shielded speakers I have just bought (they are replacement speakers used in TVs), I am faced with a larger box due to its high Qts, since:
Vb = Qts^2.87 * 15 * Vas

From the formula, Qts is a nice target for reduction to lower Vb. Knowing that Qts is a result of Qms and Qes in parallel, I though that lowering Qms (since it is easier) could effectively lower Qts.

I started with applying diluted fabric conditioner on the spider (the other factor for Qms, aside from the surround). While still wet, I measured T/S parameters using Audua Speaker Workshop just for the sake of knowing what the parameters would be. Qts lowered due to lower Qms, Vas slightly increased, Qes nearly just stayed.

I thought that as soon as the spider will dry, the magic will go, and it did. The parameters returned to their original values.

So I thought about longer-lasting materials, and I thought GREASE!

I diluted bicycle grease with light machine oil and applied it generously on the spider. Measured T/S parameters again. Qms reduced by 28% (and hence, Qts), Vas increased slightly, Qes close to original. (very sorry! Data is at home, I’m currently at work. I will bring them tomorrow).

So after treating the spider with grease, my box volume design reduced by 28%.

I held the bare speaker close to my ears and played music at low volume. Perceptibly, the speaker sounds cleaner, maybe because the coloration of sound due to mechanical Q, is reduced.
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Old 27th July 2005, 09:28 AM   #2
simon5 is offline simon5  Canada
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Hehe that's a good idea I guess, you could patent it!
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Old 27th July 2005, 12:55 PM   #3
Badeck is offline Badeck  Philippines
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I thought about it too, ha ha!

I will bring the T/S data (before and after the grease) tomorrow.
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Old 27th July 2005, 01:00 PM   #4
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Quote:
Hehe that's a good idea I guess, you could patent it!
No, not anymore. For being patentable an invention must be new. Publishing an idea before filing destroys the novelty.

Regards

Charles
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Old 27th July 2005, 01:51 PM   #5
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Quote:
Originally posted by phase_accurate


No, not anymore. For being patentable an invention must be new. Publishing an idea before filing destroys the novelty.

Regards

Charles
He's not "publishing" it. He's just throwing around some ideas with a few people on the internet.
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Old 27th July 2005, 02:16 PM   #6
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You may not even tell a friend about your findings without destroying the novelty. I assume this here is more widespread than just telling a friend, isn't it ?

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Charles
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Old 27th July 2005, 04:25 PM   #7
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For the US, I heard something about a year after publishing it or mentioning on a message board. Not sure about that. It would not surpirse me if the Phillipines follow the US patent law-they used to be a US territory. At any rate, a foreigner can get a US patent anyway.
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Old 27th July 2005, 05:53 PM   #8
simon5 is offline simon5  Canada
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AFAIK, here to get a patent, you must be the first to find out the idea. So Badeck could write a document about T/S and grease, get a signature from anyone for a witness, then fill a patent. If there's battles about the patent, he could point people to this thread to show he was the first on the idea.
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Old 27th July 2005, 09:13 PM   #9
scooby1 is offline scooby1  Australia
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Default lower power handling?

correct me if im wrong but wouldnt putting grease on the spider hinder cooling of VC?
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Old 27th July 2005, 11:44 PM   #10
theNoid is offline theNoid  United States
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Just be careful as to what kind of grease and oil you are using on what kind of spider material. The immediate results may be grand, but the end result could be complete failure of the spider and/or other soft-parts on the driver.

Noidster
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