Bandpass Question

jwatts · 30th May 2006, 09:58 PM

I am having a difficult time designing a bandpass box because the ports are to long and won’t fit inside the enclosure. My question is this. If I can preserve the front and back enclosure volume ratios can I simple multiply both by a factor and make them larger. The enclosure is a 4th order bandpass.

Example.

Assume was originally calculated to be.

Vf=.3ft^3
Vr=.5ft^3

Can I simply multiply both Vf and Vr by 3 and not change my passband, ripple, and Fb for the enclosure.

lndm · 30th May 2006, 11:23 PM

To make a vent shorter, you could make it narrower. Still, try to keep it as wide as possible. A really long vent can cause resonance problems anyway.

Have you considered mounting the vent outside the box?

jwatts · 30th May 2006, 11:31 PM

My current application will not allow me to vent outside of the enclosure.

Ron E · 31st May 2006, 12:18 AM

Quote:

Originally posted by jwatts
Can I simply multiply both Vf and Vr by 3 and not change my passband, ripple, and Fb for the enclosure.

No. Use a PR.

Jonathan Bright · 31st May 2006, 12:25 AM

Is there any possibility of bending the ports inside the enclosure?If you use plasitc pipe the purchase of 90 degree joints etc is v.easy.

jwatts · 31st May 2006, 01:13 AM

Does anybody have any experience using a PR in this type of application? If so does perform as well as a port.

30th May 2006, 09:58 PM	#1
jwatts diyAudio Member Join Date: Jan 2004 Location: Erwin, Tennessee	Bandpass Question I am having a difficult time designing a bandpass box because the ports are to long and won’t fit inside the enclosure. My question is this. If I can preserve the front and back enclosure volume ratios can I simple multiply both by a factor and make them larger. The enclosure is a 4th order bandpass. Example. Assume was originally calculated to be. Vf=.3ft^3 Vr=.5ft^3 Can I simply multiply both Vf and Vr by 3 and not change my passband, ripple, and Fb for the enclosure.

30th May 2006, 11:31 PM	#3
jwatts diyAudio Member Join Date: Jan 2004 Location: Erwin, Tennessee	Impractical My current application will not allow me to vent outside of the enclosure.

31st May 2006, 12:25 AM	#5
Jonathan Bright diyAudio Member Join Date: Feb 2004 Location: Queensland	Is there any possibility of bending the ports inside the enclosure?If you use plasitc pipe the purchase of 90 degree joints etc is v.easy. __________________ "It was the Spring time of the year when aunt calls to aunt like mastodons across the frozen waste." P.G. Wodehouse.

31st May 2006, 01:13 AM	#6
jwatts diyAudio Member Join Date: Jan 2004 Location: Erwin, Tennessee	Pr Does anybody have any experience using a PR in this type of application? If so does perform as well as a port.

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30th May 2006, 11:23 PM	#2
lndm diyAudio Member Join Date: Mar 2006 Location: nsw	To make a vent shorter, you could make it narrower. Still, try to keep it as wide as possible. A really long vent can cause resonance problems anyway. Have you considered mounting the vent outside the box?

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