Whats the risk of sound cancellation or standing waves, etc. in a rectangular box with exterior dimensions of:
W- 22"
H- 22.5"
D- 17.5"
I understand its best to stay away from any type of cube, so, with an enclosure such as this, are there any problems with the shape?
Also, when using a port length calculator, when you type in the CF, PTF, amount of ports, diameter, etc., and it gives you the length on the port......are you supposed to ADD .75" to the number the calc. gives you, or not? FROWN
(.75" being the width of the enclosure's board)
Also, are you supposed to factor in displacements (driver, ports, braces) BEFORE you enter the cubic footage of the box into the port length calculator or not? FROWN
Thnx, just tryin to clarify this in my brain & get everything perfect for my next box.
DM
Replies (4)
danielm87 on 02/11/2005 10:59:06
Oh sorry i forgot.........Please...?
swez on 02/12/2005 09:33:46
You are on the right track. Yes, need to factor in sub displacement number(s) as well as port displacement numbers to dial everything in close.
Standing wave on that box will be minimal and if you used some poly fill or acoustical damping materials like fiberglass, that will almost eliminate any major standing wave issues.
About adding 0.75" board thickness, if the port is mounted through the port hole, no need to adjust port length. However, if you rear mount the port flush to inner wall, yes.... reduce port length by board thickness of the baffle panel.
FYI: We have some leeway on sub enclosures. A +/- 10% variation off the recommended enclosure specs will produce very good results. If a given sub has a recommended port enclosure range of say... 1.5 - 2. 0 cf, shoot for 1.75 cf + sub and port displacements. This will give you very good results. A good blend of SPL and power handling on a given sub.
Hope that helps,
Swez
danielm87 on 02/12/2005 12:04:08
THANK YOU
DAVE.
DM
swez on 02/13/2005 03:47:38
Most welcome Sir Daniel !
Swez
W- 22"
H- 22.5"
D- 17.5"
I understand its best to stay away from any type of cube, so, with an enclosure such as this, are there any problems with the shape?
Also, when using a port length calculator, when you type in the CF, PTF, amount of ports, diameter, etc., and it gives you the length on the port......are you supposed to ADD .75" to the number the calc. gives you, or not? FROWN
(.75" being the width of the enclosure's board)
Also, are you supposed to factor in displacements (driver, ports, braces) BEFORE you enter the cubic footage of the box into the port length calculator or not? FROWN
Thnx, just tryin to clarify this in my brain & get everything perfect for my next box.
DM
Replies (4)
danielm87 on 02/11/2005 10:59:06
Oh sorry i forgot.........Please...?
swez on 02/12/2005 09:33:46
You are on the right track. Yes, need to factor in sub displacement number(s) as well as port displacement numbers to dial everything in close.
Standing wave on that box will be minimal and if you used some poly fill or acoustical damping materials like fiberglass, that will almost eliminate any major standing wave issues.
About adding 0.75" board thickness, if the port is mounted through the port hole, no need to adjust port length. However, if you rear mount the port flush to inner wall, yes.... reduce port length by board thickness of the baffle panel.
FYI: We have some leeway on sub enclosures. A +/- 10% variation off the recommended enclosure specs will produce very good results. If a given sub has a recommended port enclosure range of say... 1.5 - 2. 0 cf, shoot for 1.75 cf + sub and port displacements. This will give you very good results. A good blend of SPL and power handling on a given sub.
Hope that helps,
Swez
danielm87 on 02/12/2005 12:04:08
THANK YOU
DAVE.
DM
swez on 02/13/2005 03:47:38
Most welcome Sir Daniel !
Swez
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