Discussion About Box Options

[Mister.Lull]

Hey Everyone,

It's been a while since I've been on here (car got wrecked, so I didn't
have much of a need to discuss car audio)... But now I have a new(er)
car, and I'm ready to start with a new box (I've still got most of my
old equipment).

I was playing around with WinISD yesterday, figuring out what box
volume I should go for and what type/size/shape of ports I should have,
when I had a really interesting idea. I thought, "I wonder how many
ports (and at what size) I would need to simply make the port length
3/4 of an inch (the thickness of the MDF I'll be using)." So I started
plugging in numbers, and moving them around until I found a combination
that worked and wouldn't whistle. I don't have the exact numbers but
it was something like 15, .2inch, 3/4inch long ports would work.
Essentially this means that if I drilled 15 1/5inch [does that size bit
exist?] holes into the box, then it would be ported to the frequency I
had designated (26 Hz or so) - taking into consideration box volume and
sub parameters etc...

Has anyone seen this done, or tried it themselves? I know that WinISD
is just a basic program that's designed to HELP build a box, and not to
be trusted as gospel, so I'm not even sure if it's telling me the truth
(that it can be done). It seems to me that if it worked then I
would've seen a box or two like that, or that this might at least be
more common practice...

Thoughts?

~Mister.Lull

[95Honda]

It will whistle.

And it will act like an Aperiodic dampened alignment and not a ported
one.


--
95Honda

[Mister.Lull]

Okay..........
Are you willing to elaborate? Perhaps get a little more technical?
Share some experience you (or someone you know) had with this?
I'm not going to doubt you, indeed I can't since I've never tried this,
but I'd like to discuss it - not simply be told that it won't work.
Here's my main reason why I'd like to discuss this: WinISD has (among
a butt-load of other features) a mach rating. Get the mach rating too
high and the port(s) will whistle. With the configuration described
above, the mach was WELL within acceptable limits.
~Mister.Lull
95Honda wrote:
> It will whistle.
>
> And it will act like an Aperiodic dampened alignment and not a ported
> one.
>
>
> --
> 95Honda

[keith]

Actually, he's using WinISD already, and it looks likes he gets the
physics behind the mach rating.

I say try it... After all, what have you got to loose? $20 worth of
materials, and an afternoon?

KeithS


Jackson wrote:

> On 31 Aug 2006 20:04:07 -0700, "Mister.Lull" >
> wrote:
>
> He's right as it definitely will whistle! "Port noise". There's not
> much to explain as it's simple physics in play here. Air passing
> though a restricted orifice will create noise. Can you hear whistling
> through window panes with the windows all the way open or cracked? Can
> you whistle through your lips with your mouth wide open or puckered?
> Take your specs to a free online box calculator
> http://www.subwoofertools.com/forum/ported-box.asp for a simple, no
> frills box designed to achieve the sound you want.
>
>
>>Okay..........
>>Are you willing to elaborate? Perhaps get a little more technical?
>>Share some experience you (or someone you know) had with this?
>>I'm not going to doubt you, indeed I can't since I've never tried this,
>>but I'd like to discuss it - not simply be told that it won't work.
>>Here's my main reason why I'd like to discuss this: WinISD has (among
>>a butt-load of other features) a mach rating. Get the mach rating too
>>high and the port(s) will whistle. With the configuration described
>>above, the mach was WELL within acceptable limits.
>>~Mister.Lull
>>95Honda wrote:
>>
>>>It will whistle.
>>>
>>>And it will act like an Aperiodic dampened alignment and not a ported
>>>one.
>>>
>>>
>>>--
>>>95Honda

[Mister.Lull]

In the end I abandoned this idea. You're right, though, I could try it
and see - but I have to drive out of town to do any stereo stuff, and I
like to have a box plan that I know will sound good (or as close to
knowing as one can with car audio) before I go. I live near downtown
Seattle, so I don't have a garage... Anywho, I decided on an upward
firing sub and two upward firing ports.

If anyone gets a wild hair up their ass and wants to try this, Great!
Do it and call it the Lull Box. :-)

~Mister.Lull
keith wrote:
> Actually, he's using WinISD already, and it looks likes he gets the
> physics behind the mach rating.
>
> I say try it... After all, what have you got to loose? $20 worth of
> materials, and an afternoon?
>
> KeithS
>
>
> Jackson wrote:
>
> > On 31 Aug 2006 20:04:07 -0700, "Mister.Lull" >
> > wrote:
> >
> > He's right as it definitely will whistle! "Port noise". There's not
> > much to explain as it's simple physics in play here. Air passing
> > though a restricted orifice will create noise. Can you hear whistling
> > through window panes with the windows all the way open or cracked? Can
> > you whistle through your lips with your mouth wide open or puckered?
> > Take your specs to a free online box calculator
> > http://www.subwoofertools.com/forum/ported-box.asp for a simple, no
> > frills box designed to achieve the sound you want.
> >
> >
> >>Okay..........
> >>Are you willing to elaborate? Perhaps get a little more technical?
> >>Share some experience you (or someone you know) had with this?
> >>I'm not going to doubt you, indeed I can't since I've never tried this,
> >>but I'd like to discuss it - not simply be told that it won't work.
> >>Here's my main reason why I'd like to discuss this: WinISD has (among
> >>a butt-load of other features) a mach rating. Get the mach rating too
> >>high and the port(s) will whistle. With the configuration described
> >>above, the mach was WELL within acceptable limits.
> >>~Mister.Lull
> >>95Honda wrote:
> >>
> >>>It will whistle.
> >>>
> >>>And it will act like an Aperiodic dampened alignment and not a ported
> >>>one.
> >>>
> >>>
> >>>--
> >>>95Honda

[almond]

i'm sure it would act as a leaky box. i think that with the ports that
short it wouldn't really work. i'd do a little more research on it.


--
almond