Design ideas needed for diy lightweight cab/combo

[1n3]

There have been some good suggestions here on the DIY side. Here's an exercise based on the Eminence Medium Sealed cab reference. The next step - translating parameters to dimensions - is trivial to some, but not all.

The OP's loft opening is 18", so I'll start by setting the cab width to 16". For 1/2" plywood, that makes the baffle 15" wide.
Baffle height: The speaker hole dia is 9.18"; I'll round that to 9.25". Adding 2" around the holes (2+9.25+2+9.25+2), puts the baffle height at 24.5", making the cab 25.5" high.

Baffle area is 367.5 square inches. To find the interior depth that gives target volume of 2CF/3456CI: 3456/367.5 = 9.4"; I'll round that to 9.5. An internal depth of 9.5" gives an internal volume of 3491.25ci or 2.02cf. That's a little over the spec'd volume, so allows for some bracing. I'd brace around the middle as shown below.

If you extend the cab an inch beyond the baffle front, external cab dimensions are 16w x 25.5h x 11.5d. Those are pretty normal proportions for a 210 bass cab.

I picked Eminence's "Medium Sealed" because it's easier and the speaker is optimized for sealed. But if you added the vents, this cab would be pretty close to the Small Vented design. I'd probably make it .25" deeper if I wanted to have that option later.

 

[t0neloc]

There have been some good suggestions here on the DIY side. Here's an exercise based on the Eminence Medium Sealed cab reference. The next step - translating parameters to dimensions - is trivial to some, but not all.

The OP's loft opening is 18", so I'll start by setting the cab width to 16". For 1/2" plywood, that makes the baffle 15" wide.
Baffle height: The speaker hole dia is 9.18"; I'll round that to 9.25". Adding 2" around the holes (2+9.25+2+9.25+2), puts the baffle height at 24.5", making the cab 25.5" high.

Baffle area is 367.5 square inches. To find the interior depth that gives target volume of 2CF/3456CI: 3456/367.5 = 9.4"; I'll round that to 9.5. An internal depth of 9.5" gives an internal volume of 3491.25ci or 2.02cf. That's a little over the spec'd volume, so allows for some bracing. I'd brace around the middle as shown below.

If you extend the cab an inch beyond the baffle front, external cab dimensions are 16w x 25.5h x 11.5d. Those are pretty normal proportions for a 210 bass cab.

I picked Eminence's "Medium Sealed" because it's easier and the speaker is optimized for sealed. But if you added the vents, this cab would be pretty close to the Small Vented design. I'd probably make it .25" deeper if I wanted to have that option later.
View attachment 4632497

Many thanks for this. I'd come to similar dimensions, give or take a bit. I think I'll give it a go and match it up with a mini head to maximise the portability.

 

[t0neloc]

Just a further thought before I commit to a medium 2x10 cab based on the Eminence parameters - thanks to 1n3 for confirming my interpretation of the dimensions needed.
I'm wondering whether two separate 10" cabs would be better. Use one (16ohm) for practice as the power isn't really needed and hook up both in parallel for more oomph at 8ohms. Considering a Warwick Gnome head to go with these cabs.
Am I being simplistic in thinking that I'd just half the volume of the cab or would that throw the design well off target?

 

[abarson]

Just a further thought before I commit to a medium 2x10 cab based on the Eminence parameters - thanks to 1n3 for confirming my interpretation of the dimensions needed.
I'm wondering whether two separate 10" cabs would be better. Use one (16ohm) for practice as the power isn't really needed and hook up both in parallel for more oomph at 8ohms. Considering a Warwick Gnome head to go with these cabs.
Am I being simplistic in thinking that I'd just half the volume of the cab or would that throw the design well off target?

No doubt that 2 x 110 is easier to maneuver, but I think you should go with 8 ohms speakers instead of 16 ohms. There is a bigger selection and you end up with 4 ohms total, which is the typical minimum for amps, including the Gnome.

 

[agedhorse]

1/2 of the 210 x 2 cabinets is exactly the same as the 210 provided the internal volume is the same and the porting is the same (ie. 2 x the porting for the 210 cabinet compared with the 110 cabinet).

 

[S-Bigbottom]

Before building anything out of wood, make a cardboard box about the size of the cabs you are considering.

Now take that empty cardboard box and load it up that ladder and back down a few times, now add some weight to it near the weight of a cab and repeat the load up and down.

You will quickly see that going up and more especially down that ladder with the box, leaving a cab up there is going to be very appealing.

 

[t0neloc]

No doubt that 2 x 110 is easier to maneuver, but I think you should go with 8 ohms speakers instead of 16 ohms. There is a bigger selection and you end up with 4 ohms total, which is the typical minimum for amps, including the Gnome.

I agree on the 16ohm thing. It's just that I picked up the two unused speakers for under £18 each. I probably should have planned this a bit better. I may sell them on and get a suitable 4 ohm 12-15" driver for a single unit cab.
On the other hand, I love a challenge and they're already here.

 

[1n3]

I agree on the 16ohm thing. It's just that I picked up the two unused speakers for under £18 each. I probably should have planned this a bit better. I may sell them on and get a suitable 4 ohm 12-15" driver for a single unit cab.
On the other hand, I love a challenge and they're already here.

That's a good price - $23.67 USD each at this writing. I don't share the desire to always load an amp to it's minimum impedance. Especially since this is primarily for your music room, an 8ohm 210 seems like a good plan. Separate 110 cabs would be more work, and the combined weight would be higher.

 

[JimChjones]

To my mind people get too excited about watts. 2 10s isn't a whole lot of cone area, which is arguably more important if volume is required. And 2 16ohm 1*10s means you can add another 8ohm cab if volume ever is an issue. Also taking a 2x10 up a ladder doesn't sound like fun at all. Perhaps while you're building cabinets you should consider making some kind of sled to run on the ladder so you can pull the cabs up with a rope and pulley system? Probably save the cabs a lot of bashes too.

 

[agedhorse]

That's a good price - $23.67 USD each at this writing. I don't share the desire to always load an amp to it's minimum impedance. Especially since this is primarily for your music room, an 8ohm 210 seems like a good plan. Separate 110 cabs would be more work, and the combined weight would be higher.

Why do you have a problem with running an amp an its minimum rated impedance?

 

[1n3]

... I don't share the desire to always load an amp to it's minimum impedance.

Why do you have a problem with running an amp an its minimum rated impedance?

My quote bolded for emphasis. The context you may have missed is the suggestion that OP should trade the 16 ohm speakers he has for a pair of 8 ohm speakers, to achieve a 4 ohm load.

For the TL/DR crowd: OP wanted a combo or cab for his loft, which is reached by a ladder. He got a deal on a pair of Eminence Basslite SC10s, and is interested in a DIY cab for those speakers. Eminence says they're "optimized specifically for sealed bass cabinets". Based on that info, we've discussed a cab based on Eminence's "Medium Sealed 2x10" cab option. It'd be a simple build. If he doesn't like it, he can sell the cab. If he likes it and needs to get louder, he could build a second cab, and "get all his watts".