9518 SC 4th Order Bandpass

[Evyn1]

I’m trying to figure out the port volume needed.

I currently have: (2) 6”X23.5”. Volume: .76.

Because I want the sub to hit louder and it doesn’t seem to have enough flow.

It’s tuned to 33HZ. 6.75 cubic feet shell (after displacement).

I was thinking:
(4) 6”X42”. Ports. Volume: 1.54.

That .78. 2X. More port volume.

Any suggestions?

Thanks.

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[SlugButter]

Who designed your 4th order? They don’t work the same way as a ported box does. If your ports are tuned to 33 HZ, you likely have a very limited bandwidth and only hit a few of the lower bass frequencies. Winisd and Hornresp are both good software programs to design 4th orders. You can’t just guess with 4th order or 6th order designs or you will not get the results you want.

 

[Evyn1]

Who designed your 4th order? They don’t work the same way as a ported box does. If your ports are tuned to 33 HZ, you likely have a very limited bandwidth and only hit a few of the lower bass frequencies. Winisd and Hornresp are both good software programs to design 4th orders. You can’t just guess with 4th order or 6th order designs or you will not get the results you want.

Yeah I actually got like 100 rebased songs that hit in its Bandpass perfectly. I’m not sure what the bandwidth looks like. I just tried a 3:1.

I gotta say the songs that hit within its Bandpass are remarkably clean. I know the Amp is tuned perfect to 33.

I know the software is nearly mandatory, just pulled an experiment.

I’d say the experiment is a semi-success if the song falls within its Bandpass it’s an unreal experience!

Still a work in progress.

thanks

 

[Evyn1]

So I think if I ran a passive radiator 18”, with the performance SPl.

That would be better for my 4th Order than (2) 6” ports?

Maybe if I invert the Passive Radiator I can tune the 4th order from fs:17, to 50.
And see what hz tuning works.

But both subs would be inverted.

 

[mr roo]

is this a ported enclosure or a 4th order? If 4th and tuned to 33hz, unless specifically designed to do that, it wont have any bandwidth. It might only play 40 down if that. Years back I knew a guy that had a big 4th order tuned that way, but he 4 8" playing 50 to 100. The bandpass was tuned to play 45 down so was tuned to something like 35 hz.