Rebuilding a cabinet for bass use
 

I'm looking for some advice. I have an old Peavey115H PA cabinet that I would like to use for my electric bass rig.
I need to replace the speaker and the horn.

Can I put an eminence 300watt speaker in this cab?
When I took the grill off I noticed 4 open slots around the speaker. Does that mean the speaker is ported or vented?

Any suggestions for which components to use is greatly appreciated

Thanks
Paul

Hi Paul.

If the said Eminence models nicely to the cab, then the answer is yes, otherwise not likely.

We replaced the drummers Peavey 115 PA bottom speakers with Eminences back in the day, and they modeled pretty well, even with the cheap-skate baffle ports Peavey is so keen to use.
Can't really remember which ones, but around á~70€.

If the "4 open slots" are just holes in the baffle, without any tube-like structure, just input the individual area and # of those "ports" and use the baffle thickness as the length of the port.

In a case like Yours, WinISD Beta is more than adequate program to do the modeling IMHO.

Regards
Sam

More questions for Sam
 

Sam
Thanks for responding. By "modeling" do you mean there is a program that I can enter the cabinet dimensions, figure out the cabinet volume and then be able to determine a speaker for the cab?
I know I'm in over my head. I just want to make sure I but the right new speaker, horn and the input panel.

Thanks again
Paul

Hi Paul.

You're welcome.

There is several programs available to model a speakers behaviour in a given box, and IMHO/IME the WinISD is the best free one.

I do suggest resisting the urge to try the Alpha PRO though. It's about as complete as it gets (for a free one anyway ;)), but unless the user knows exactly what to do and how to input the variables and the parameters, nothing will be plotted.

IMHO the WinISD Beta is the way to go.

Programs like that won't handle anything but modeling the woofer though, the cross-over and the Hi-freq device has to be chosen with the aid of experience and/or trial and error measurements.

I'd personally skip the idea about the Hi-freq device for MI bass use. Not because -according to some people- the upper frequencies aren't needed for bass, they sure are, but because it makes the project un-necessarily complicated.
If there's enough room in the baffle, I'd look into 6" mid-range speaker instead.
For that approach, there's the fEarful threads to learn from :).

Regards
Sam