Advice for building a box for a newb help please!!

[caveman93]

I want to build a boombox type speaker system out of all the old components from my old car system and use it in my apartment. I've built my own boxes before, but only for subs, so what I need help with here is figuring the proper dimensions for a box for midrange speakers to get the right acoustics etc. Here's a very basic sketch of what i'm thinking in my head right now.

The crosses represent the cutouts for the speakers and the box in the middle is where the cutout for the head unit will be.

Here's all the parts i'm forking with not sure how relavent this informtion is but here it is:
- 4x 6.5" powerbass 2XL speakers (90W RMS @3 Ohm each)
- Rockford P400-4 amp
-1 4x8 sheet of 1/2" MDF
-110 VAC to 12V 30A power supply

TL;DR
Need help designing box for a midrange speaker box

Also what do you guys think about filling the box with some polyfil?

 

[sreten]

Hi,

Although it might seem to you a good idea, trust me it isn't.

Keep the car stuff for cars. Build something far more civilised
and refined for use indoors, trust me, your ears will approve.

rgds, sreten.

 

[caveman93]

Hi,

Although it might seem to you a good idea, trust me it isn't.

Keep the car stuff for cars. Build something far more civilised
and refined for use indoors, trust me, your ears will approve.

rgds, sreten.

I just have these extra parts that are just sitting around useless right now and I want to do a cool project. I know it won't be as good as just buying an indoor stereo but this is what I want to do

 

[chrisb]

I guess that's the great thing about DIY - if you build things carefully enough, you can recycle / repurpose undamaged parts forever

I'm with sreten on keeping car audio components to their intended venue for sonic reasons, but if it keeps your hands busy, why not? - you might be quite happy with the results.

 

[sreten]

Hi,

If it was a box to make some noise in a workshop I'd be all for it.

However indoor quality boom boxes are just poor, and yours will be worse.

A while back a friend challenged me to put together a system to
compete with what he thought was a great sounding indoor box
for the same price.* Needless to say my system slaughtered it
in all respects. It had an I-pod type dock.** Later on I added
an old (pristine) Sony portable CD player that also crushed
all the devices that plugged into the dock for quality.***

All I'm saying is don't fool yourself about what you want.

rgds, sreten.

* He thought it was as good as it gets, I was unimpressed.

** Cambridge Audio dock, used original Rega Brio amplifier,
Wharfedale floorstanding speakers, Richer Sounds specials.

*** Nice old Sony portable, with a line out, that was anything
but portable in reality as it jumped all over the place jogged.
It wasn't cheap when it was new, clearly hardly used.