Cabinet questions

[Human Fly]

Good evening, morning or day where ever you're at. I have been looking to build myself a speaker cab for cheap as a hobby project and in the process have bumped into some questions which have proven themselves to be hard to google and hoped i could find some answers here.
As i have understood it a speaker needs a certain volume (the space kind not the sound kind) within the cab to function properly. When building a 212 cab do you need to accommodate both speakers separately or can they "share" the space within?

 

[KevInDaBassment]

Lotta variables, based on how you want to build or utilize it.

I'm guessing this is being asked in the generic sense, so for a 30,000ft view answer, I'll say "Yes, many cabs have both speakers sharing the same internal space."

Which ones to use, how much space, porting, etc is an entirely different barrel of monkeys. I'd start with something that already has plans and hardware lined out...Greenboy and Bill Fitzmaurice are my suggestions, as they line out specs for cabinet AND speakers with their designs. YMMV, but I'd go in this for the fun of it. Cost and time effective solution would be to buy a used, already-made cab. If you're in it for the experience, good luck and have fun!

 

[Redbrangus]

Yes, there are lot more questions that would need to be resolved, but two identical speakers can operate in the same acoustic space. They can't 'share' the space, i.e., if the recommended enclosure volume for one 12" driver is 40 liters, a 212 cab with two of those same drivers would need to be 80 liters or thereabouts. Dissimilar drivers absolutely should not operate in the same enclosure space.

 

[agedhorse]

I have been looking to build myself a speaker cab for cheap as a hobby project

This alone suggests that quality will be a challenge. If you need a cabinet, you can usually get a MUCH better deal on a good used and proven cabinet than you can building one yourself. ESPECIALLY if size and weight aren't a big concern.

 

[Wasnex]

Good evening, morning or day where ever you're at. I have been looking to build myself a speaker cab for cheap as a hobby project and in the process have bumped into some questions which have proven themselves to be hard to google and hoped i could find some answers here.
As i have understood it a speaker needs a certain volume (the space kind not the sound kind) within the cab to function properly. When building a 212 cab do you need to accommodate both speakers separately or can they "share" the space within?

Yes matching drivers can share the same chamber. It's actually very common. AFAIK, when you double the drivers, you must double the volume of the cab and double the area of the ports. The length of the ports stays the same.

It's not clear that you understand, porting and the internal volume of the cab design are adjusted to suit the driver's Thiele/Small parameters. Some drivers work better in a small box and others work better in a big box. Some work better in sealed box and some work better in a ported box.


Also there are different ways of tuning the cab. Changing the tuning effects frequency response, low frequency cutoff, and mechanical power handling.

Most of the Pro series Eminence drivers have published cab design docs. The doc for a given driver typically includes several tunings with different internal volume, I.E. small, medium, large, etc. The docs also include charts that show performance results. I suggest reviewing spec sheets and cab design docs for several drivers.

You should be able to download the spec sheet and tuning doc for the 2512 here: DELTALITE 2512 | 12

There are free programs that will model how drivers work in a given cab. You input the cab's internal volume and port parameters. You also input the driver's T/S parameters. The program crunches the numbers and display results.

 

[JimChjones]

Also worth noting that fixtures and fittings can really cost. If you are going to finish your cab in Tolex, give it a nice grill cloth and have new handles and corners, everything to make it look good it will not be cheap. That stuff really adds up! That's why, as AH says, it works out cheaper to buy a reasonable secondhand cab than it does to buy a new driver and build a cabinet. Sad but true. If you want a budget cab then I'm afraid it really is going to look like it, rope handles perhaps, painted in black emulsion paint and so on. And even then there isn't going to be a big saving on reasonable secondhand, especially if secondhand is something old school and heavy, which are sometimes ridiculously cheap.

 

[FunkHead]

This alone suggests that quality will be a challenge. If you need a cabinet, you can usually get a MUCH better deal on a good used and proven cabinet than you can building one yourself. ESPECIALLY if size and weight aren't a big concern.

Exactly, ie; I have a Nice 1x15 Avatar Cab that will get very loud for $125. It's even got a New Eminence Ca-154 in it.

 

[RattleSnack]

I remember having builder make me Bergantino cab clone some 20 years ago. At that time I couldn't find one localy, and everything else I looked at was either crap or too expensive, so that made sense.
These days, even local used market has wide offering (of course YMMV).
Last cab I bought, I got to try with my amp head and bass and decide was it worth.
My recommendation is to first check everything used and new localy you might like, than if nothing satisfies you - make your own.

 

[Raf Seibert]

While Greenboy and Bill Fitzmaurice have good plans reasonably available, I believe both specify specific drivers to be used with their plans for best outcome. This means you won't get a good result using cheaper speakers. In this business (cabinets), as in many others, you get what you pay for. There aren't really cheap alternatives.