6th order question

[galacticmonkey 5,000+ posts]

Ill be having 2 BTL 18s pretty soon. Thinking of maybe trying a 6th order. Have 2,000rms for each and about 24 cubes total to work with internally after double layering whole box.

Ive done alot of 4th orders, but never a 6th order. Im looking for a series tuned, not parallel tuned. I really want good output from the low 20hz region to about 50hz.

What would be a good enclosure to try? What airspace, tuning, and port area for the front and rear chambers?

Click to read more...

 

[thevic24 5,000+ posts]

if 80inches is still around, shoot him a pm. he is really good at designing bandpass boxes.

 

[80INCHES 5,000+ posts]

24 cubes is fine gmonk...u have room for it...10cubes tuned to 32hz for the rear chamber 14cubes tuned anywhere between 60-75hz and u should be fine...

make sure its series tuned

oh wait u have a avalanche now....go parallel tuned

heres a pic of a parallel tuned box in a avalanche...



80

 

[galacticmonkey 5,000+ posts]

I heard a 6th order for a single BTL 18 that was series tuned and the thing was nasty. Never heard a parallel tuned.

If I did a series tuned with the specs you gave, how much port area should each port have?

 

[80INCHES 5,000+ posts]

I heard a 6th order for a single BTL 18 that was series tuned and the thing was nasty. Never heard a parallel tuned.
If I did a series tuned with the specs you gave, how much port area should each port have?

hmm u lookin at 120 square inches for the 10cube chamber and atleast 300 for the 14cube chamber...make it as big as u can

80

 

[PV Audio 5,000+ posts]

What's the difference between a series and parallel tuned BP?

 

[Immacomputer 10+ year member]

Series tuned has one chamber firing into the other ported chamber volume while a parallel tuned bandpass will have both ports firing to the environment.

 

[S.B.C. 10+ year member]

Parrallel tuning will def get nasty

rear tune to 30- front tune to 65

 

[PV Audio 5,000+ posts]

Series tuned has one chamber firing into the other ported chamber volume while a parallel tuned bandpass will have both ports firing to the environment.

Wait a minute, so series tuned is just a double bass reflex?

 

[Immacomputer 10+ year member]

Wait a minute, so series tuned is just a double bass reflex?

Close but not really. In that picture, only the port drives the second chamber while in a 6th order bandpass, the speaker fires into both chambers. A double bass reflex enclosure will not have a bandpass response and thus isn't a bandpass. I believe it is still a 6th order filter though, just not a bandpass.

 

[80INCHES 5,000+ posts]

agreed

80

 

[PV Audio 5,000+ posts]

Close but not really. In that picture, only the port drives the second chamber while in a 6th order bandpass, the speaker fires into both chambers. A double bass reflex enclosure will not have a bandpass response and thus isn't a bandpass. I believe it is still a 6th order filter though, just not a bandpass.

No I understand what a 6th order bandpass was the second definition that you gave: the shared panel between the two ported chambers has the drivers:

And as typical, a 4th order is:

I know that a DBR doesn't have a bandpass response at all since it's mainly used for full-range drivers, which is what I was wondering what the difference is, aka, what am I missing?

 

[galacticmonkey 5,000+ posts]

4th order: Sealed back chamber, ported front chamber.

Parallel 6th order: Ported back, ported front. Both ported to the outside.

Series 6th order: Ported back, ported front. Back ported into front chamber, front chamber ported to outside.

Im messing around with Sketchup... Idk what I want to do.

 

[MisterGrubbs 5,000+ posts]

There are the people who I trust the most with enclosure designs all in this thread

Interesting.

 

[galacticmonkey 5,000+ posts]

I dont really have enough room for a series tuned 6th order going with the specs 80 gave. Wish I did. End up a couple cubes short on the front chamber. //content.invisioncic.com/y282845/emoticons/crap.gif.7f4dd41e3e9b23fbd170a1ee6f65cecc.gif