please help on calculating air space

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could someone please help me calculate the airspace i need, its confusing the hell out of me.

i would like 2 of these speakers
Goldwood GW-8028 8" Butyl Surround Woofer 8 Ohm

in a vented box

also if someone could help me figure out size of the port that would be great!

i also plan to have two tweeters in the box as well but in there own inclosure
Does everyone think this is a good mix?

thank you!
Qts is way too high for a ported box. Depending on your expectations, it probably too high for a sealed box too, it's going to have a bump in response even in an infinitely large sealed box, in a small box the bass bump will be obnoxious (unless that's what you want).

It's easy enough to sim this, including the port velocity, but you need to state your goals, like tuning frequency and desired size. But it's not going to be pretty in a vented box.

This woofer was made to be a replacement woofer for old worn out sealed cab or open back cab drivers in very low spl systems. It's not really good for much else.
Thanks for the quick reply.

Oh right I didnt know that it was made for what I would like it for. I'm just learning all of this. Haha

Can you please post a speaker that would really suit my needs. I want to make a portable speaker about length 60cm height 40cm width 25cm
Can change though
Depends on your goals and budget. That's a fairly large box, the driver you already picked would kinda work ok in that if it were sealed box, but it won't give flat response.

Parts Express has the recommended box size and type for each driver I believe, and you can probably even search for drivers based on that criteria with their selection menus.

But I would recommend finding out what is available locally first and simulating those options. Shipping to your country is very expensive and there should be some good local options.
If you just want a good, well designed, affordable 2 way speaker box it might be better to just buy a commercial model. Based on your questions it looks like it might take quite a bit of studying for you to properly choose drivers, design an enclosure, (ideally measure the drivers, both t/s parameters and later in box frequency response although you can skip this part if you want and use manufacturer's published data) and design a proper (not textbook) crossover.

In the US there was a very decent 2 way selling for around $50, the Andrew Jones Pioneer, not sure which model. They had a small waveguide for the tweeter, decent but economical drivers, a well designed crossover and a nice finish.

You could probably get a pair of these locally for less than the price of shipping a single woofer from the US.

Speaker design, especially proper crossover design, is not something you can learn overnight. There's a lot more to it than meets the eye. Choosing good drivers that will work with each other and designing a simple sealed or ported box for them is pretty easy compared to the complexities of crossover design. You have to consider impedance, phase, diffraction, dispersion, center to center distances and filter slopes vs comb filtering, lobing and power handling, and a bunch of other stuff. A simple textbook crossover designer like this won't result in anything but bad results - 2-Way Crossover Designer / Calculator
You need something more like this, and the knowledge to use it properly if you want good results, even for a simple 2 way - Loudspeaker Design Software
(That screenshot only shows a small portion of the spreadsheet, download it and see what you are really getting yourself into here.)

The other option is to just build a kit.

If you want a hobby that will consume immense amounts of time then go ahead, start studying and build your own. It's fun but it's not fast or easy.
Cool thanks for your help,
Im alway bored in the weekends and I was looking for something to do like a hobby of some sort. I like tinkering and building stuff and love music so I decided to try and get into this.

I had no idea it would be so involved and complicated,
I my inspiration was something like the boominator,
I have no idea on where to start learning. It's looking like
I am too uneducated for this hobby lol
Do you think you could send me a link of an example of one that would suit?

Go here
Resources - Woofer Selection Guide

Your box size is 60 liters, or roughly 2 cubic feet, so assuming you wanted both woofers to fit in that size box, you are looking for a woofer that will work in 1 cubic foot vented.
1) Click on the column header to sort by volume
2) Look for 8" (or other size) woofers that will work in roughly 1 cubic foot vented.

Have fun!

Here's one that looks to be in your price range
Dayton Audio SD215A-88 8" DVC Subwoofer
Awesome cheers mate! When you say 1 cubic foot is that air space or the total amount because I would have to take the displacement of the woofer and vent etc in consideration when size it up. How could I do this? Is there a program that allow me to draw up a plan and it measure the airspace. Or a formula? Cheers
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