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NEw BOX for the Q18
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subster87
- Senior Member
- Posts: 674
- Joined: Mon Jul 24, 2006 7:39 pm
- Location: Lock Haven, PA
- Contact:
ok well im sitting right about right then for my ports. Box is all carpeted and tomorrow night ill start glassing it down to the floor and sealing things up. Then maybe tuesday i can finish the glassing and install my amps. O well hopefully things will be running by wednesday weather prohibitting. And with those smoke stakes how high out do you have them sitting? they are only out of the box two inches... And sorry about he galbladder bet you have felt better!!! lol well heal up quick get that setup in the explorer i kinda wonna see it!!!
mmmm inverted 18!!!!:bow 
I sure hope you're OK. Unflanged ends are more succeptible to port noise. How far the ends are away from the baffle simply effects the effective length of the port. I'm still confused as what your actual net volume is, but if your gross volume is 8.25 ft^3 before port displacement and you have 3 ports 14 1/2" long with 4 1/4" o.d. which stick out 2" beyond a 3/4" thick piece of mdf then it should be 7.96 ft^3(HP calculators rock!).
This yields a 27.6Hz tuning frequency with unflanged ends(full space) or 27.3 Hz with one end flanged(half space). Since your port termination lies within one diameter of the top of your box the actual tuning frequency should lie somewhere between the two.
How much internal depth do you have between the top and bottom of your box? If you've got 17" between the top and bottom(on the inside) you could mount 3 4" ports 13.5" long "flush" with the top of the box. If indeed the box has 8.25 ft^3 before port displacement that'd give you a tuning frequency just over 28 Hz. Port noise wouldn't be as likely with that scenario.
No matter. I'd just build it and see how it sounds. You can always shorten the port lengths form the outside later or possibly build up "baffles" on the top around the smokestacks to reduce port noise.
Oh and about the gall bladder. Don't think I needed it. Modern day laparascopic surgery is amazing. I already feel better than I did before the operation and am scheduled to work a triple tomorrow. Too bad. Not gonna have as much time for this now. Was a nice vacation.
:)
This yields a 27.6Hz tuning frequency with unflanged ends(full space) or 27.3 Hz with one end flanged(half space). Since your port termination lies within one diameter of the top of your box the actual tuning frequency should lie somewhere between the two.
How much internal depth do you have between the top and bottom of your box? If you've got 17" between the top and bottom(on the inside) you could mount 3 4" ports 13.5" long "flush" with the top of the box. If indeed the box has 8.25 ft^3 before port displacement that'd give you a tuning frequency just over 28 Hz. Port noise wouldn't be as likely with that scenario.
No matter. I'd just build it and see how it sounds. You can always shorten the port lengths form the outside later or possibly build up "baffles" on the top around the smokestacks to reduce port noise.
Oh and about the gall bladder. Don't think I needed it. Modern day laparascopic surgery is amazing. I already feel better than I did before the operation and am scheduled to work a triple tomorrow. Too bad. Not gonna have as much time for this now. Was a nice vacation.
:)