SA X-18 ported - 7 cubes @ 32hz

[Boomin_tahoe 5,000+ posts]

You are using the diameter of a circle to draw these conclusions which is absolutely wrong.

port area of an octagon with 9.5" i.d. = 63.45.. Port area of a circle with a diameter of 9.5 = 70.88
He clearly used the circle dimensions as shown here. With octagon dimensions you end up with a lower ratio, less airspace due to thicker walls, and higher tuning. I would have gladly accepted suggestions if they were correct.

Dude, your calling out of one the best designers/box builders on here. Guy has been doing it for years, has had multiple successful people on here and all you can say he's doing it wrong? I would highly suggest you rethink your thinking status before this gets blown out of proportion. He obviously know's what he's doing.

 

[smashinbazzle]

Dude, your calling out of one the best designers/box builders on here. Guy has been doing it for years, has had multiple successful people on here and all you can say he's doing it wrong? I would highly suggest you rethink your thinking status before this gets blown out of proportion. He obviously know's what he's doing.

I'm sure he knows more about building boxes than I ever will, but basing the tuning of an octo off the diameter of a circle is wrong.

 

[Boomin_tahoe 5,000+ posts]

I'm sure he knows more about building boxes than I ever will, but basing the tuning of an octo off the diameter of a circle is wrong.

How do you know? Maybe he is/isn't.

@chasinbass has a few in his current build built by him.

 

[smashinbazzle]

How do you know? Maybe he is/isn't.
@chasinbass has a few in his current build built by him.

They have different formulas for area. Like I posted before = port area of an octagon with 9.5" i.d. = 63.45.. Port area of a circle with a diameter of 9.5 = 70.88

Octos also have thicker walls than aero ports so you would need the o.d. of the octo to subtract the airspace. Again i'm sure he knows way more than me about building speaker boxes but you can't argue with simple math.

 

[Boomin_tahoe 5,000+ posts]

I'll let him explain in his own words about those formulas for finding area of an octoport as that's beyond my skill/expertise area. Don't know any of that stuff.

 

[smashinbazzle]

Further, the airspace displaced by a 19" octo with 9.5 i.d. would be .93 cu ft

The airspace displaced by a 19" aero port with 9.5 i.d. would be .78 cu ft

pretty significant difference...

 

[CSCStang]

All good fellas. I'll stick to my formula that's worked for years which is very similar to the i.d. of an aeroport. There is zero audible difference between the two...real world testing many times over. Tell you what o.p., build what I suggested or go with your 113 sqin of AERO port at 16" port per (coughh) and we'll see which one works best. Never talked about port disp btw, just said arrive at 7 net. I'm out.....

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[smashinbazzle]

I don't consider pvc the same as an aero port and I didn't say I was using an aero port. My original specs were high even for a pvc port i realized that after. My only argument was that you shouldn't use the same dimensions for a circular port as an octo but w/e. It's only a difference in a few hz but that doesn't make it right.

And you mentioned the ratio, which is proportional to the displacement..

 

[Boomin_tahoe 5,000+ posts]

HA...guess what. Stang doesn't argue with people.

At this point, your on your own. Good luck.

 

[CSCStang]

Bottom line in all this is it works and works very well. You can argue all you want if that's all you feel like doing or you can build the box and enjoy the bass. Up to you really.

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[Boomin_tahoe 5,000+ posts]

I'd rather listen to bass. Life too short to argue w/ people.

 

[smashinbazzle]

HA...guess what. Stang doesn't argue with people.
At this point, your on your own. Good luck.

He didn't argue, he said I was right but that he hasn't seen any audible difference. I can appreciate that. Just funny that multiple people say that he was right to begin with without letting him respond with that in the first place which would have avoided the drama. I should have clarified my point rather than just saying he was wrong and that's on me. I appreciate the DESIGN input, I'll just do the tuning calculations on my own as perhaps I'm ocd and like to be as accurate as possible in my calculations.

The problem with the octo for this particular box is that it wouldn't fit because it would hit the sub, so I may make the box a bit smaller and make it an external octo so it's closer to 7 cubes

 

[Boomin_tahoe 5,000+ posts]

He can prob design you something on Sketchup if you ask him nicely. He might come up with a better idea.

 

[smashinbazzle]

He can prob design you something on Sketchup if you ask him nicely. He might come up with a better idea.

I'm sure he could come up with a better design. I'll ask nicely once I have the seats out and the base in so I have exact dimensions.

 

[CSCStang]

I was right in the fact that what I suggested will work and I'll even guarantee it. You can ocd all you want with the numbers but this isn't rocket science man. You can even run it through winisd if you really want to get technical...once its in the vehicle you can throw all that out the window cause real world dictates otherwise.

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