T-S parameters are off...what am I doing wrong?
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50 Watt CAFz'r
Joined: Jun 2004
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Originally posted by Dave_MacKinnon:
I use a delta mass calculation - I measure the added mass down to a tenth of a gram.
It's much harder to get to a small percentage error with volume since you have to compensate for the shape of the cone in terms of volume, reflections from internal surfaces, basket volumes, etc..
Delta Volume works great - if you can get the volume smack dab perfect.
I use a delta mass calculation - I measure the added mass down to a tenth of a gram.
It's much harder to get to a small percentage error with volume since you have to compensate for the shape of the cone in terms of volume, reflections from internal surfaces, basket volumes, etc..
Delta Volume works great - if you can get the volume smack dab perfect.
Thanks for the reply, but I don't think the volume is the problem. If you actually use the calculator, you'll see that adding or subtracting even 50% of the volume of the enclosure gives the same parameters.
In fact, the only way I could get closer to the published specs was to mess with the frequencies and voltage at fs, and in those cases the differences were so big that there is NO way that they were due to measuring error.
This is why I'm wondering where I'm getting boned. If the parameters were close, but adding or subtracting 5% to 10% to some measurements would make them closer or dead on, I would definitely assume it was something about how I was measuring. But these figures are way off and no matter how much I fudge the numbers I can't get them to line up with the specs.
molo
[ September 10, 2005, 10:57 AM: Message edited by: molo ]
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I can't remember who did it (dave Navone maybe) but there was a published test in one of the car mags where they were going to prove and disprove 'breaking in' a woofer. What they found was that some of the T/S parameters did change, but after completely cooling down (I think they let the woofer sit overnight) the parameters were back to their original measured specs.
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I haven't looked at the Volume-dependant measurements in a long time. If the air volume has that little effect on the woofers, then you can consider your specs close enough..
DW- Those guys will use math to try and prove anything. Load up a new woofer and listen to it, then break it in for ten hours and listen again, they sound better broken in.
BUT, that is a good lession in power compression.
DW- Those guys will use math to try and prove anything. Load up a new woofer and listen to it, then break it in for ten hours and listen again, they sound better broken in.
BUT, that is a good lession in power compression.
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