Adjustable cab porting?

[Jouni]

It has become obvious I don't know a lot of stuff. Cabinet dynamics is one.

But.. I've got a 4x12 cabinet, it has decent speakers (can't remember what) but it sounds like crap. Someone DIY:ed it, from solidwood, though.

It isn't very deep, and I think that's why it sounds overly middley.. has no real high or low end. Me and some friends thought that the speakers are simply too confined in the small airspace of the cab. I thought porting it might help, friend said it might, or might not.

And since I know nothing of how big of a hole it needs in the back, I thought I could just make an "adjustable" porting, and leave it where it sounds best?

Probably gonna give it a shot, now matter how cooky you guys call me.
It's bound to make some change, adjustable at that.

BUT if any of you know anything like, what approximate size hole, and where, to start...? I'd be happy to listen.

TIA

Jouni

 

[moresound]

Jouni ....before cutting the box try just the opposite.
Take out one of the speakers and stuff *pink type of home insulation* into the box behind all of the speakers replace that one speaker you took out then give it a try! I think you'll be happier with that results. Let me know what you think.

 

[ocnor]

It isn't very deep, and I think that's why it sounds overly middley.

What are the internal dimensions of the box? What is the actual brand and model of the speakers? Can you post a picture of the inside of the cab?

 

[mshilarious]

Sealed cabinets are smaller than ported cabinets; if you port a small cabinet you could get a very peaky response--which might be something you enjoy, or it might not. It will extend the bass response, but in a small cabinet you'll get a large (maybe ~3dB) peak resonance, then a sharp drop below that. That could work well if the peak is around 80Hz or so.

Sealed cabinets have a tighter sound though; porting might make it sound a bit tubbier for things like palm-muting.

I agree with the suggestion on damping; otherwise, you can experiment with porting but I'd model it in software first. You'll need the T-S parameters on your drivers, then try here:

http://www.kbapps.com/audio/speakerdesign/calculators/index.html