Hamilton Audio

hey guys. I'm an experienced box builder and have built many hundreds of successful enclosures. When going vented, I've always stuck with ABS pipe as its easy to get right. I wanna branch out to slot ports. My question is simple:

using WinISD, I can specify a sqare port. I want to put the slot port on the top face (12" wide lets say). Knowing my material is 0.75 mdf, the width of my slot will be 10.5". For a specific tuning, ISD allows me to define the w x d dimensions and it calculates the lenght. So if I tell it 10.5 x 2.5 (for example), it tells me my length is 14.5"

I know you use one side of the box as a face of the port and you cut the slot and install another panel of a given length. My question is....where do I factor in this 14.5" depth? assume I design the box to be 14.5" deep inside, I can maintain one wall....how deep does the other side need to be? In this example, ISD also tells me the cross area is 26.25 sq. in. is there an easier way to figure this out?

basically I'm looking to know the easiest way to determine the "short panel" of the slot for a given tuning. how do you factor in the width of the slot? can anybody help me understand this?

bmoney

[ August 28, 2004, 08:03 PM: Message edited by: Hamilton Audio ]

Fever

iTrader: (1)

Which part of your question was simple? [img]smile.gif[/img]

I think ISD is telling you the 10.5x2.5 slot port needs to be 14.5" long, simple as that.

If you want the internal wall to be one straight piece, you will have to add another 2.5" internal enclosure length to accomodate the opening of the port into the enclosure.

You can also have the port turn the corner inside the box. You would measure the port length down the middle of the port, and turn the corner in the middle of the next length of port (1.25" from the end in your ex.) and continue 'till you get the length you need.

More difficult to do, but opens up more design possibilities.

Here's a link to a similar thread. SlotPorts

[ August 29, 2004, 07:35 AM: Message edited by: Fever ]

Chadxton

iTrader: (1)

Slot ports are my salsa. [img]graemlins/thumb.gif[/img]

M.X.C. TECH

Hamilton Audio I just wrote a tech tip for our company on this. If you PM me your email address I will send it to you. That goes for any one else as well.

MTA

iTrader: (1)

its fairly simple..make the opening as you've mentioned... 10.5x2.5 if your box is externally 14.5" deep thats perfect ... your port wall if using 3/4" wood should end 2.5" away form the bottom of the box, meaning 10.5"...since the internal depth of the enclosure is 13"(assuming you're using 3/4" wood)...

when calculated using all formulas the length seen by the subwoofer(s) will be 14.5" but the physical length is a bit less. if it is required to use a longer port...the port length can be FOLDED in an "L" shape and determine the length by measuring through the centre. if this is a bit confusing here is a link that is somewhat usefull

SLOT PORT HELP

good luck...I personally prefer slot ports