First time box design - opinions?

[Dragonfish]

I picked up a Fosgate P1S2-8 and I'm working on a slotted box for it. The specs call for a .65 ft3 box but when I put it into WinISD I found I got more output in a 1.5 ft3 box with the port tuned to 40 hz. Would you mind looking at this and let me know if it looks ok? This is my first time designing a box and I followed the sticky at the top of this forum.

1.5 ft3 adjusted to 1.85 ft3 for port and driver displacement

2" x 12" x 23" port

Driver info:

FS: 40

Re: 1.8

Le: 1.16

Qms: 2.88

Qes: .48

Qts: .54

Vas: 12

Sd: 211

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[CSCStang]

I picked up a Fosgate P1S2-8 and I'm working on a slotted box for it. The specs call for a .65 ft3 box but when I put it into WinISD I found I got more output in a 1.5 ft3 box with the port tuned to 40 hz. Would you mind looking at this and let me know if it looks ok? This is my first time designing a box and I followed the sticky at the top of this forum.
1.5 ft3 adjusted to 1.85 ft3 for port and driver displacement

2" x 12" x 23" port

Driver info:

FS: 40

Re: 1.8

Le: 1.16

Qms: 2.88

Qes: .48

Qts: .54

Vas: 12

Sd: 211

Did you plot this with power added? What's the vent mach?

 

[Dragonfish]

If that means the port air velocity chart, it maxes out at 78.2 ft/s at 38hz. Is that too high?

 

[CSCStang]

If that means the port air velocity chart, it maxes out at 78.2 ft/s at 38hz. Is that too high?

As long as you're under 100 ft/s you're good.

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[Dragonfish]

Everything else looks ok? Thanks for looking!

 

[Boomin_tahoe 5,000+ posts]

Imo, that's tuned too high. Highest I would go is 35Hz. But that's me and we have a lot of peeps on here that listen to low bass.

What's your music preference that this enclosure is tuned so high?

 

[Dragonfish]

I mostly listen to classic rock and metal but I do still like some boom. I had originally tuned to 35 hz but I found I got a LOT more output at 40. I was worried that it wouldn't be loud enough at 35. Should I post up the 35 tune?

edit: ok I guess I just need to make the port 1.29" longer to tune it to 35. Everything else is the same. I do lose some SPL but it flattens out the graph a bit too so that's good.

 

[Dragonfish]

Sorry, math. 8.29" longer port which makes it too long for the box. I have to do some reworking.

 

[Dragonfish]

If I narrow the port down to 1.5" x 12" it shortens up considerably, and reduces the port air velocity quite a bit. Is 1.5" wide too small?

 

[lsvtec]

following this post. trying to learn and see what people are responding..

 

[CSCStang]

What's your velocity at 18 sqin? Above 55 below 100 ft/s is the acceptable range.

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[Dragonfish]

98 ft/s at 33 hz is the peak at 500w input. Is that RMS or peak measurement?

At 1125w (which is the max the amp will put out) it jumps up to 145 ft/s. I'll have to keep it turned down to about halfway.

 

[Dragonfish]

What happens when it goes over 100?

 

[Dragonfish]

It's weird, if I plug Rockfords suggested box and port dimensions it tunes the box to 41.69 hz. Isn't that too high?

 

[Jeffdachef 5,000+ posts]

Imo, that's tuned too high. Highest I would go is 35Hz. But that's me and we have a lot of peeps on here that listen to low bass.
What's your music preference that this enclosure is tuned so high?

not everyone likes low notes. 40hz is completely acceptable to people listening mainly to metal and other rock genres. 35hz and under tuning is just plain garbage for those types of music genres especially with low cone area. what good is it to peak in the 30s when all your bass notes in your music are in the upper 40s to 50s which is where your bass response starts dying out horribly being tuned to low 30s.