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Some port simulations in-room for a Tempest (1 Viewer)

Darryl_St

Grip
Joined
Aug 15, 2002
Messages
21
Hi all,

I'm about to build two Tempest based subs and was going to use a 190L tuned to 19Hz with 1-4" flared port.

When I sim this box in LspCAD it looks good, but if I turn on simulate nonlinearity I lost a lot of the low end in-room.

Should I expect this sim to be correct?

All these have about the same group delay.

Can I just have some tubes half-way out of the box for maximum low end? ( They will be behind a false wall out of site ).

Will tube lengths cause other anomalies that I will hear?

I can tune slightly higher say 22Hz, which will shorten them and only increase group delay slightly, but will give me even greater low end.


Have a look,
( oops, I can't post the pic )

190L 19Hz 1-10.5x26.9cm port 114.8db @ 20Hz Nonlinearity off
190L 19Hz 1-10.5x26.9cm port 109.3db @ 20Hz Nonlinearity on
190L 19Hz 4-10.5x129.4cm port 112.1db @ 20Hz Nonlinearity on
190L 19Hz 1-15.2x62.7cm port 110.8db @ 20Hz Nonlinearity on
190L 19Hz 3-15.2x208.5cm port 112.7db @ 20Hz Nonlinearity on

Thanks

Darryl
 

Jeff Rosz

Second Unit
Joined
Sep 24, 2000
Messages
335
well for starters, you could (i would) rule out the 4" ports, go with 6". yes you can have the tubes half out of the box.
 

Darryl_St

Grip
Joined
Aug 15, 2002
Messages
21
Thanks for the response,

Have you ever seen or heard of an example of a box with the ports half out?

Do you know if the nonlinearity in LspCAD sim is correct?

I just looked at using an 8" ( 21 cm ) port 101cm long tuned to 21Hz will give me 112.7db @ 20Hz.

That's 3db more @ 20 Hz then a 4" ( 10.5 cm ) port 26.9cm long tuned to 19Hz.

These are all with 125W into 8 ohm.

Darryl
 

Darryl_St

Grip
Joined
Aug 15, 2002
Messages
21
Just wondering if anyone had any real world experience with a LspCAD sim and a test done on a real sub,

Do you know if the nonlinearity in LspCAD sim is correct?

Will longer tube lengths cause other anomalies that I will hear?

Thanks



Darryl
 

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