DIY - 212 cabinet - help with ports calculation

Hard to say without plugging into winISD. Sounds roughly in the ballpark although I would have expected slightly longer ports, not that I have worked with high excursion 12''. If you can rig up ports with duct tape and cardboard temporarily you can fine tune them by experiment before glue.

How's your power handling with 55hz tuning?

Something else to consider is dual cabinets. It's nice to grab one little cab for rehearsals

 

50L per driver or 1.76 / 1.8 cubic feet
Sounds about right. Probably offer little more power handling.

2.2 to 2.6 cubic feet per driver probably offer more bass response. Depends on the driver.
Or about 62 to 68 L per driver

Im looking for data sheet.

Most tend to high tune. I typically prefer tuning low as possible.

Can be as simple as tuning to Driver Fs.
And typically stick to larger BB3 or BB4 alignments.

Some will go with higher tunings to squeeze extra 60 or so watts. And fiddle around with non true alignments

I find it pointless and tend to tune low for better transients. Hence using BB3 or BB4
Alignments.

Which basically tune to driver Fs then adjust volume according to driver Vas.

Given better transients and lower bass.
F3 will be high in the model.

Real life with normal EQ = equals more bass

Haven't seen driver driver specs yet. I'll assume if Fs is high. The driver likes smaller volume has decent high-end and just tune at Fs or 2/3 hz below.

Just remember to get correct port length subract driver and bracing volume. And assume and subtract the rough generic port volume to get correct length. Likewise if your using single flare ports use correct end factor correction.

Like the bracing. Looks shallow try make deep as possible. And liking the width.

 

You are on the way to design a pedigree Tschebyscheff alignment (4th order Tschebyscheff HPF).
IMO/IME that's not a good idea with bass cabinets

 

Why not just build a fearful 12, 12 6?

greenboy's fEARful downloads

 

What's your sound goals?
WinISD is a fudging freeware tool anyway.

 

I just meant why not go with somthing already worked out and proven to sound good. Sorry for any trouble.

 

What does WinISD get wrong, that would be of concern to a DIY speaker builder? I compared graphs from WinISD to ones produced by my own derivations from basic electromechanics, and they were in good agreement. The laws of physics are the ultimate freeware.

 

It used to be known for overestimating port lengths.

 

That's fair. One thing I would always do with any software is to cut the ports a bit long and adjust them after testing. "Measure twice and cut thrice" is my motto. Or something like that.

 

OP fella is going to use adjustable ports, clever.
KoziejMaclowski will you glue the baffle in place or only use 10 screws?

 

One suggestion - my experience is that the internal damping has a far greater effect on the sound than the port tuning. I strongly advise constructing the cabinet in such a way that you can readily change the amount of damping material in early testing and development, and only once you are satisfied gluing everything in place.

If your development access will be through the front baffle I would double the number of screws on it. I had access through the back and was staggered by how much more it moved than I had expected.

 

I would glue the baffle in once you have finished. It adds a lot of extra over screws, and assuming the drivers are front loaded then you'll have enough access for maintenance.

 

Over here, we use T-nuts with threaded fasteners if we don't use plain old wood screws. Regardless, you need a fastener every 100-125mm or so.

And what's going on in the area behind the ports? It looks to me like the bracing is forming resonant cavities separate from the main chamber...kind of like a band-pass enclosure. Is that part of the intent of the design?