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Discussion Starter #1 (Edited)
Dual Opposed RSS390-ho4 or HF (11.5 Cu) - long, low 12-15hz - Help needed

I've been playing around with form factors and think I found one that works for me.

NOTE - Now considering the 390HF in 11.5 cu


The problem is the ports. I can't get the velocity and 1st resonance to work.
Either the velocity is too high or the resonance too low.

I am modeling the xmax and power according to Ricci's tests (slightly lower than the 18 measurements he got.)

It shows they can handle my full Crown XS900 which should give them 2200+ w at bridged 4ohn or 2 ohm stereo.

It models really nice except for the port.
The best I can get is:

Option 1:
2 ports --- 8" x 3.23" x 64.27" each
Peak noise --- 28.88ms @ 13.4hz
First resonance --- 105.27 hz

Option 2:
2 ports --- 7" x 3.23" x 55.99" each
Peak noise --- 29.52ms @ 14 hz
First resonance --- 120.83 hz

18 x 18 (approx 16 x 16 internal) x 72 long
Each driver would be on the far ends (6ft apart).
Estimate 9'cu internal

Tune 15hz
4th order HPF at 13 hz

124db at 100hz
121db (f3) at 35hz
118db (f6) at 22hz
114db (f10) at 15hz

Looks perfect for my space and should be very easy to move (MOVE out of a house I mean.)

Can anyone get the port to work?
 

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Tuning to 15hz with only 4.5 cubic feet per driver is going to be tough. 20hz would probably work better.

The speaker listed in your title doesn't exist. It's either the 390 15 or the 460 18. If you're using the 18 there isn't a panel large enough to fit the driver.
 

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Discussion Starter #8 (Edited)
I'm no expert in this but if you're crossing over at 80hz then port resonance above that is not going to matter. There will be chuffing with high air speeds.
So does the last one I posted look good or is that still too fast?

This also looks pretty good...

Would have to run the ports to the middle - Have them touch them touch for about 9-10 inches up and then bend back for 8-9inches.

If I use this as a base for center braces and use dual opposed it should be a pretty solid cab
 

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Discussion Starter #12
You should try modeling the Alpine SWR15. It works better in a smaller box and has a lot more throw then the Dayton.
And doesn't it cost twice as much?

I am thinking these look good...

How important is group delay?

The lower you tune the lower it goes... Is it worth a bigger box and lower tune to get lower group delay?

Also part of my goal is to lower power needed which is why I like the HF a bit more
 

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Discussion Starter #17
The difference is one is severely exceeding xmax and the other isnt. The real world results will not match winisd, in that the one exceeding xmax by that much will not be linear.
It feels like using geometric xmax is being figured against dayton where alpine uses tested so you're thinking it has more xmax...

Not saying you are wrong just what the models are saying...

The one benefit of the alpine is slightly better port resonance and velocity factors
 
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