I am changing the mid range speaker in an old three way system that I built many years ago. I have reconed the woofer and it "seems" to be fine.
In rethinking about this old box of mine I realized that I had originally built it as a tuned port style. I no longer have the datasheet for the woofer but when I went to Radio Shacks' old spec section on the web I was able to find a Model # 400-1023 (mine is 40-1023B) so thought I would recalculate the existing port size, length, response,etc. (FYI... the physical description seems to fit my woofer).
When I looked at the numbers from the web it showed a test box resonance of 52.53 Hz and a free air resonance of 12.71 Hz. Do these numbers seem to be consistent, that's quite a difference? All the other parameters seem to make sense.
If the 12.71 Hz value is correct there is no way I should have tried a tuned port approach with an inside volume of 2.5 cubic feet. I tried to calculate backwards to Fs using other parameters (Vs, Vb and Fb) and came up with a different result than the web datasheet.
Does anybody have a different data sheet and/or any comments on my concerns?
Many thanks for any/all comments!
In rethinking about this old box of mine I realized that I had originally built it as a tuned port style. I no longer have the datasheet for the woofer but when I went to Radio Shacks' old spec section on the web I was able to find a Model # 400-1023 (mine is 40-1023B) so thought I would recalculate the existing port size, length, response,etc. (FYI... the physical description seems to fit my woofer).
When I looked at the numbers from the web it showed a test box resonance of 52.53 Hz and a free air resonance of 12.71 Hz. Do these numbers seem to be consistent, that's quite a difference? All the other parameters seem to make sense.
If the 12.71 Hz value is correct there is no way I should have tried a tuned port approach with an inside volume of 2.5 cubic feet. I tried to calculate backwards to Fs using other parameters (Vs, Vb and Fb) and came up with a different result than the web datasheet.
Does anybody have a different data sheet and/or any comments on my concerns?
Many thanks for any/all comments!
Not too many woofers have an Fs that low, certainly not from RS. It's a misprint. Also, since you have reconed the woofers, the old parameters no longer apply. You'll have to have them remeasured.
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