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Tweakers' Asylum Tweaks for systems, rooms and Do It Yourself (DIY) help. FAQ. |
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Tweakers' Asylum Tweaks for systems, rooms and Do It Yourself (DIY) help. FAQ. |
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In Reply to: For a round port posted by jnorv on January 8, 2007 at 15:50:00:
I had (incorrectly?) deduced (deluded?) that a slot-loaded port should seem half as long again*, times 1.5! [Or was it one fifth / times 1.2?].IE that is where it's impedance minima would shift down to, lying between the two 'new' peaks. the new operating frequncy being that of a port one and half times as long. Nope?
That is, in a port in a baffle that is 38cms in diameter and (both port, driver and baffle) face the floor at a distance of let's say 2 (or 3) inches!
What factors help me determine the height of the loading slot?
So adding 3cm (half the i.d. of the port) to 15cms the current length, and that slot-loading will only ever add 3cm's to a 6cm i.d. port. Giving 18cm's as the effective port length of the existing system facing down onto a 60cm diam. paver loading the 38cm diam round baffle with a 5cm gap.
Correct?
AND, ..... Even if I make the port longer by deepening the baffle by 5 cm, still gives a total effective port length of 15 + 5 + 3 => 23cm's.
I doubt that's going to change the Fb much of a smallish 23litre enclosure. I need to lower the Fb from 38 to 27hz, to 2/3rds at least.
WarmestTimbo in Oz
The Skyptical Mensurer and Audio ScroungerAnd gladly would he learn and gladly teach - Chaucer. ;-)!
'Still not saluting.'
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Follow Ups
- If you ARE right I can only ever add 3 cms to a 6cm bi.d. port! Even IF it and the driver are slot loaded!? - Timbo in Oz 16:24:00 01/08/07 (3)
- here's a ref, to the 1.5 times theory - Timbo in Oz 18:26:29 01/08/07 (2)
- After reading your previous post (below) - jnorv 19:34:58 01/08/07 (1)
- Thanks for that! and you could also try over at Inmates - LONG - Timbo in Oz 00:35:57 01/09/07 (0)
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