I often find myself in possession of drivers without the T/S parameters. I am making a spreadsheet listing parameters for drivers in their original enclosures.
1) Driver diameter.
2) Cabinet Volume.
3) Port Tuning Frequency.
What other information do I need? Is power handling relevant?
1) Driver diameter.
2) Cabinet Volume.
3) Port Tuning Frequency.
What other information do I need? Is power handling relevant?
I suppose you mean technical data? None of those that you list are T/S parameters.
Loudspeaker Database
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Loudspeaker Database
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No. That's not it.
Let me give you an example. I have a perfectly good driver taken from a Yamaha YST subwoofer. There's no clue as who actually manufactered the driver so the TS Parameters are unavailable. What I can tell you is that it is rated at 100w RMS and was in a 17 litre cabinet with a port tuned to 42Hz. And I'm going to assume Yamaha knew what they were doing.
What other information would help when the TS parameters are unavailable?
Let me give you an example. I have a perfectly good driver taken from a Yamaha YST subwoofer. There's no clue as who actually manufactered the driver so the TS Parameters are unavailable. What I can tell you is that it is rated at 100w RMS and was in a 17 litre cabinet with a port tuned to 42Hz. And I'm going to assume Yamaha knew what they were doing.
What other information would help when the TS parameters are unavailable?
You can do better than to trust that the manufacturer has used the optimal enclosure. You need the T/S parameters, which you can easily measure. I have often found that the enclosure used is different from what I would have designed for that driver. Also, the power specification published by the manufacturer for the completed subwoofer is not necessarily that of the driver. The power spec should only be used as an indicative guideline.
[Anecdotal] Your comment reminds me of a chastising I received many years ago from a mechanic. "A stock Rover V8 engine produces 155hp. The F1 engineers at Cosworth can extract 600hp from the same power-plant. The difference is that Leyland have to guarantee for 2 years or 30,000 miles. An F1 engine has to last two hours!"
Anyway . . . in the practical world. I've just sold the plate amplifier from a Gale Atomic-8. Because we're supposed to be being all green and stuff - what should I do with the driver?
Anyway . . . in the practical world. I've just sold the plate amplifier from a Gale Atomic-8. Because we're supposed to be being all green and stuff - what should I do with the driver?
Measure the Thiele-Small parameters. Then you have the information required to decide what to do with it.
If I may ask, why did you sell the plate amp only and not the subwoofer as a whole?
If I may ask, why did you sell the plate amp only and not the subwoofer as a whole?
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The YST system uses the old Audio-Pro subwoofer patent where physical parameters are manipulated by a negative output impedance amplifier - trying to estimate T/S parameters for a driver that has been in such a system, judged from the cabinet, is 100% surely bound to fail.
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The parts are almost always more valuable the whole. Subwoofers are hefty, the cost money to ship. Let me give an example: I have a subwoofer than I believe their cat has used as a scratching post - it's worthless. But as separate items the driver and the plate amp have value.
Eh, kinda useful. You can make an impedance measuring device for about £10, though, so I'd just go ahead and get the full data set.
Chris