contruction and function of bandpass

[terra 5,000+ posts]

im trying to do a bp with 2 18"s as well..

 

[hemi=22s 10+ year member]

im trying to do a bp with 2 18"s as well..

sweet bump for da bp box u doin 4th or 6th order bp

 

[JG903 10+ year member]

Yes, tune the front chamber just as a ported box.

The cut out looks decent.

 

[terra 5,000+ posts]

sweet bump for da bp box u doin 4th or 6th order bp

depends on the size requirements. Have like 13 cu. to work with..

Rough plan was 4 cubes sealed for the pair and 8 cubes for the ported at 30hz..

 

[energizedsbs 10+ year member]

just a question. isnt a bandpass box tuned different? i have a 15 in a bandpass that 80 designed. its tuned to 55hz which was like around 30hz in a normal ported enclosure. just wondering about that.

 

[PV Audio 5,000+ posts]

That probably means that it peaks at 30hz, or the lower end of the passband rolls off at 30hz.

 

[JG903 10+ year member]

I have always been told that tuning a bandpass high is for spl purposes just like vented enclosures.

Alan told me to make a effecient 4th order enclosure to make the front chamber 18 cubes //content.invisioncic.com/y282845/emoticons/eek.gif.771b7a90cf45cabdc554ff1121c21c4a.gif tuned to iirc 40.

Also if you read some literature that some manufactures publish about box specs they tune thier bandpass boxes to like 40hz as well. For instance the JBL 15" W15GTI series sub bandpass specs the front chamber is tuned to 40 hz for a daily box.

Link here: http://manuals.harman.com/JBL/CAR/Boxes%20and%20Parameters/W15GTi_rev_f.pdf

 

[PSturmer 10+ year member]

4th order is a sealed rear chamber and ported front. these are easy to design and build. 6th order both rear and front chamber are ported at different frequencies. these are known as "bass reflex" boxes. much more difficult to design and construct. generally 6th orders are hard to get a flat curve for daily and they are very difficult to function in an spl application. bose uses 6th order for the subwoofers in home audio. (they also hold the patent to this design)