bass reflex box design

I've seen this design a few times and it really seems to produce impressive bass results in both loudness and quality. I'm not familiar with posting diagrams so i'll use 0s to create the design of the box:

0000000000000000000000000000000000000 0                                   0 00000000000000000000000000          0 0                                   0 0          00000000000000000000000000 0                                   0 00000000000000000000000000          0 0                                   0 0          00000000000000000000000000 0                                   0 0         00000000000               0 0        0           0              0 0       0   SPEAKER   0             0 0000000000000000000000000000000000000

This design basically creates a kind of maze behind the speaker. What is this design, How does it work, What are the advantages and disadvantages of this design? Any particulars about design a box of this design? Thanks.

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Prodigal Son

Bass reflex = ported system.  Assuming there is an exit in the top left corner of your diagram, all that represents is a long port.  If there is no exit from the enclosure, then it is simply a sealed (acoustic suspension) system.

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If the port exit is at the upper left, looks to be a transmission line.

yes it is a ported system. I've seen this design used in ready made sub enclosures. What are the advantages of this enclosure design? I've noticed that with this design the port can span the length of the box with this design. I've been told that the partitions in this design are best at 2 inches apart. The nautilas (hope i spelled it right is an expensive system of speakers noted for quality. It's design is like that of a snail shell. Can i assume that these long ports have a greater advantage to them?

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Prodigal Son

transmission line . . .The tapering tube can be coiled for lower frequency driver enclosures to reduce the dimensions of the speaker resulting in a seashell like appearance. Most notably Bowers & Wilkins have used this approach in their flagship Nautilus speaker as well as the use of smaller straight tapering tubes in many of their other lines.

In a previous post "transmission line", haemphyst did an excellent job explaining the benifits. My last post came from an article from wikipedia about different types of enclosures.

It's not a transmission line if the size of the port remains constant.  If it is the same size from start to finish, it is a bass reflex enclosure.

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haemphyst did mention this:
A port is just a device to tune an enclosure to a given resonance. Remove the enclosure, and buld the port SO big, that you can stick the woofer on the end of it, and there you are - a TL. Oversimplified, certainly, but basically... Instead of an air pump moving air through it, it's a speaker moving air through it.

Yes, a "speaker at the end of a long tube" can be stuffed and tuned like a transmission line.  A true TL uses a tapered line, with the TQWT approach being most common.

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DYohn] wrote:

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Yes, a "speaker at the end of a long tube" can be stuffed and tuned like a transmission line. A true TL uses a tapered line, with the TQWT approach being most common.

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DYohn, from reading the material from quarter-wave.com a transmission line can have a taper or a 1-1 area ratio throughout the line

So is this design a folded 1:1 ratio TL? Is the drawing primitive enough that a taper is not illustated? Would there be enough volume around the driver to constitute an enclosure or is it just the opening to start a port or TL?

it depends on the design..

it could be a small ported box with a long port or a chambered t-line