Vifa PL-18 on Ported Box MJK´s WS

[JC Fardo]

OK this is my PL-18 sim in ported box WS

1. XO incorporates BSC, and is from Ken Perkins´ Nebula project

http://www.partsexpress.com/project...ula/nebula.html

2. PL-18 parameters are measured average of four

3. Port diam. radius is 1.32" obtained from Home depot PVC wire duct

Any correction and comments will be extremely appreciated

Thanks

JC

[andrikos]

Hey, hey.

I used 16 Vifa PL18's for my Line Array projects.
They're great midwoofs. I'm very happy with them.
Good luck with yours.

[andrikos]

Oh yeah, mine are sealed (1.5ft^3).
8" x 13" x 60" outside dimensions.
1.5" thick all around.

Going from outside in:

1) 8 layers of Tung oil / mineral spirit / polyurethane mix (1/3rd each)
2) 18mm 13ply Baltic Birch
3) Titebond Premium wood glue
4) 2mm extreme dynamat
5) Titebond Premium wood glue
6) 3/4" MDF
7) Titebond Premium wood glue
8) 2mm extreme dynamat
9) 3M spray glue
10) 1.5" thick egg crate foam from PE
11) Polyfill from PE (1/2 lb per 1ft^3)


Whew! That's a LOT of layers (and work )

[GM]

>Any correction and comments will be extremely appreciated

====

Looks good to me. FWIW, here is what I calculated:

L = 38.53"
zd = 14.03"
zp = 36"
SO/SL = 52"^2
rp = 1.25"
Lp = 4.75"
density = 0.2lbs/ft^3

Not sure what 'wire duct' you are referring to, but around here 2.5" PVC pipe is available and why I used rp = 1.25".

====

>Whew! That's a LOT of layers (and work )

====

No kidding! I got tired just reading it.

GM

[JC Fardo]

GM

Thanks for calculations

Is it an issue if port hole is on front or back (to backwall) of enclosure? This newbie must be wrong again but I see no predictions in the WS´s

Have a nice weekend

=================

andrikos

Impressive work those lines, I recall similar design in a McIntosh catalog some time ago and thanks for share pics. Unfortunatelly not for my pocket (and room). I hope PL-18 sound as good as predicted in a ML-TL

JC

[GM]

GM

Thanks for calculations

Is it an issue if port hole is on front or back (to backwall) of enclosure? This newbie must be wrong again but I see no predictions in the WS´s

Have a nice weekend

You are welcome!

No. No, the worksheet does not allow you to choose, so the accuracy decreases some higher up in the BW, but it is not an issue unless you use no stuffing, and even then it is debatable as to whether you can hear the minor peaks that would occur.

You too! Always wanted to go to Brazil when I retired, but things happen, so I seriously doubt I will.

I hope PL-18 sound as good as predicted in a ML-TL

The worksheets have good accuracy overall, so with published specs they should be strong performers within their excursion capability. Remember, it is a half space sim and the room dominates down low, so some EQ and BSC will probably be required.

Anyway, please give us a review and what all you had to do WRT BSC, XO's, etc..

GM