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I'm getting frustrated in Win modeling right now....maybe I'm screwing something up. I can't get velocity and 1st port Res anywhere near where I'd like to while having anything resembling a manageable port length..for round ports that is. I can make a slot work by running it up the back. Trying to keep 1st res above 160 and velocity at 20m/s or less
 

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Discussion Starter #23
This has some good info on original testing, pics are gone but I believe still on Marks website

 

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Discussion Starter #25
I'm getting frustrated in Win modeling right now....maybe I'm screwing something up. I can't get velocity and 1st port Res anywhere near where I'd like to while having anything resembling a manageable port length..for round ports that is. I can make a slot work by running it up the back. Trying to keep 1st res above 160 and velocity at 20m/s or less
What are the box dimensions and are you modeling with 6"ports?
 

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Discussion Starter #27
Somethings off, with one port plugged I get the low tune. 2 ports open is 19hz. Bot are flared on both ends 26" long, flare not included

What is the box hxwxd

Part of the discussion I linked to was about keeping the port closer to the back wall affects the port tune and will make it work as if it was longer.
 

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I have it at 15ft3 net...14hz tune, 2 6" ports have to be like 44" and it still has me showing 28m/s max velocity and only 155hz for 1st port res
Thats going to happen with a tune that low. I can double check your numbers when I get home, but I don't think your numbers are that off.

Keep in mind the X21 is around 10cu/f internally tuned to 19hz.
 

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Thats going to happen with a tune that low. I can double check your numbers when I get home, but I don't think your numbers are that off.

Keep in mind the X21 is around 10cu/f internally tuned to 19hz.
Even modeling the X21, 10cubes and two 6" ports at 19hz keeps port resonance under control, but velocity is up to 30m/s. ...model the one port plugged option and it goes all the way to almost 60...
 

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Even modeling the X21, 10cubes and two 6" ports at 19hz keeps port resonance under control, but velocity is up to 30m/s. ...model the one port plugged option and it goes all the way to almost 60...
Also depends on the driver for m/s, but from what I remember the X21 did ride a little high on port velocity with the 21SW that Ricci posted.
 

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Discussion Starter #34
Something to consider, between 12 and 18 hz are the problem areas. How much sustained content will be in that range to cause consistent issues. My 2 are 10 ft away and I've never heard any chuffing, I push them hard but I don't overdrive. You can use larger ports but you'll be driving the port resonance lower. Popovich has a nice PR build going, compromise with them as well.

Here's a good discussion at DB


If that wasn't enough this will fill your cup to the brim

 

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Hi im new on this forum. I have two b&c 21ds115-4
This is what i want to build.
Do somebody have plan to share with me please... :D
 

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Discussion Starter #38
No plans, I can give you some measurements how i put mine together. I went from Mark's dimensions and pictures. It would be next weekend before I'd have time to pull a driver and give exacts. Mine are 36" deep as opposed to Mark's which was 32" I believe. You need to figure that part out, generally you can tweak it how you want as long as you don't cramp the port entrance/exit and volume.
 

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I haven't even received my four HS-24's yet and I already want to build at least a pair of these too...and a pair of horns of some sort, and...

I'm gonna have to buy a bigger house some day :rolleyes:
 

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Omg that will be awsome... ill wait for it.
I saw on bass data some measurments, and thats a hell of a sub.... did you make some crossovers ?
 
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