Bandpass Boxes

[btdickey99 5,000+ posts]

I was just wondering the advantages/ disadvantages of going with a 1st order bandpass, 2nd order, 3rd, 4th etc?

How would this be compared to a ported box?

This is assuming that both type boxes are built properly

Thanks

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[chillin 10+ year member]

I believe a properley built bandpass will be louder but take up more space. But Ive been wrong before.

 

[Immacomputer 10+ year member]

Um... there is no such thing as a 1st order Bandpass or second or third. The order comes from the DE used -- it's not just a name.

 

[btdickey99 5,000+ posts]

Um... there is no such thing as a 1st order Bandpass or second or third. The order comes from the DE used -- it's not just a name.

shows how much I know.....

sorry guys

 

[PV Audio 5,000+ posts]

I may be wrong in this assumption, but it makes sense to me. I believe the word bandpass is derived or is directly related to passband, which is an area of the audio spectrum. In a filter circuit, you have a low pass and a high pass circuit. For 3-way designs, you add a bandpass filter which comprises the middle of the spectrum. This is called the passband, or area between your upper and lower limiting frequencies. It looks roughly like a plateau which rolls off very quickly at either end i.e.

The red is your highpass rolloff, green is the lowpass rolloff, and the blue hump is the bandpass rolloff, or passband for this particular filter.

What a bandpass enclosure does is that it essentially chooses two frequencies to be tuned to (literally for a 6th order bandpass, but we'll keep it to 4th order), and the area, or passband, between those two frequencies is greatly enhanced or boosted, much like a ported enclosure. However, much UNLIKE a ported enclosure, the bandpass enclosure's frequency response is very narrow in comparison, which is why you generally only use the design on low frequency drivers where they only have a small bandwidth to cover. As such, they are very easy to design, but extremely difficult to design correctly. I know not of a single commercial bandpass box that is designed correctly, and they consequently get loud, but sound absolutely awful (akin to farting, as some put it). Hope that helped, but if not, just let me know or someone else correct me so you can get a better explanation. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

-Dave

 

[btdickey99 5,000+ posts]

I may be wrong in this assumption, but it makes sense to me. I believe the word bandpass is derived or is directly related to passband, which is an area of the audio spectrum. In a filter circuit, you have a low pass and a high pass circuit. For 3-way designs, you add a bandpass filter which comprises the middle of the spectrum. This is called the passband, or area between your upper and lower limiting frequencies. It looks roughly like a plateau which rolls off very quickly at either end i.e.

The red is your highpass rolloff, green is the lowpass rolloff, and the blue hump is the bandpass rolloff, or passband for this particular filter.

What a bandpass enclosure does is that it essentially chooses two frequencies to be tuned to (literally for a 6th order bandpass, but we'll keep it to 4th order), and the area, or passband, between those two frequencies is greatly enhanced or boosted, much like a ported enclosure. However, much UNLIKE a ported enclosure, the bandpass enclosure's frequency response is very narrow in comparison, which is why you generally only use the design on low frequency drivers where they only have a small bandwidth to cover. As such, they are very easy to design, but extremely difficult to design correctly. I know not of a single commercial bandpass box that is designed correctly, and they consequently get loud, but sound absolutely awful (akin to farting, as some put it). Hope that helped, but if not, just let me know or someone else correct me so you can get a better explanation. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

-Dave

That did help a lot and appreciate it....So to sum up things..... If designed correctly the bandpass box will be a better box for burping?

 

[PV Audio 5,000+ posts]

That did help a lot and appreciate it....So to sum up things..... If designed correctly the bandpass box will be a better box for burping?

Maybe, I don't compete so I'm not sure. Ask someone like tommyk who actually does. I don't want to tell you yes since I don't know.

 

[BrianChia 10+ year member]

I know not of a single commercial bandpass box that is designed correctly

BOSE //content.invisioncic.com/y282845/emoticons/fyi.gif.9f1f679348da7204ce960cfc74bca8e0.gif

//content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[Blinkdogo2 10+ year member]

bandpass is not better for burping, look at the world record holders they dont use bandpass, why would u want to turn an 18" sub into a couple 4" ports,, bandpass is to make shitty subs sound better

 

[BrianChia 10+ year member]

bandpass is not better for burping, look at the world record holders they dont use bandpass, why would u want to turn an 18" sub into a couple 4" ports,, bandpass is to make shitty subs sound better

false

 

[btdickey99 5,000+ posts]

Now I am confused and would like to have someone with a great deal of experience answer the question

 

[JimJ 5,000+ posts]

bandpass is not better for burping, look at the world record holders they dont use bandpass, why would u want to turn an 18" sub into a couple 4" ports,, bandpass is to make shitty subs sound better

//content.invisioncic.com/y282845/emoticons/hilarious.gif.02a037aad04aa96f19982b298a3d70a8.gif

 

[duece212 5,000+ posts]

bandpass is not better for burping, look at the world record holders they dont use bandpass, why would u want to turn an 18" sub into a couple 4" ports,, bandpass is to make shitty subs sound better

didn't somebody win some driveby event at a record level with a bandpass enclosure in a van recently?

 

[bdawson72 5,000+ posts]

//content.invisioncic.com/y282845/emoticons/hilarious.gif.02a037aad04aa96f19982b298a3d70a8.gif

//content.invisioncic.com/y282845/emoticons/hilarious.gif.02a037aad04aa96f19982b298a3d70a8.gif:hilariou:

 

[btdickey99 5,000+ posts]

^^^hes laughing at you