DIY Speaker cab and experiment.

[LimeB]

Hi Pete, when you do those measurements, is it just plucking one note on one string and taking a tiny "snap shot" of that ? Time is not one of the axis on the graph is it?
If that is the case is it crucial to take the sample at exactly the same time/ decay point?

[Petebass]

Hi Pete, when you do those measurements, is it just plucking one note on one string and taking a tiny "snap shot" of that ? Time is not one of the axis on the graph is it?
If that is the case is it crucial to take the sample at exactly the same time/ decay point?

Nah it's much easier than that now. The software sends a sweep if sine waves that starts at 20Hz and finishes at 20K (I can vary these frequencies but that works well for what I'm doing). It measures the response through a calibrated microphone and plots it on a logarithmic graph where dB is one axis and Hz is the other.

The whole thing takes about 5 seconds per sweep

[Petebass]

Update. I retired from performing in Jan 2013. At the time these cabs were 2.5 years old and had done many gigs. I'm pleased to say they are still in near-new condition and have easily lived up to the rigors of being carted around from gig to gig.

They aren't being used at the moment - but who's to say I won't make a comeback at some stage? If I do, these will definitely become my go-to cabs. Or maybe my twins will grow up to be musicians? (they are due to be born any day now). If so, they'll surely appreciate the lack of weight of these cabs. I've also found they make great Party speakers and with lots of 40th and 21st in the circle of family and friends, the cabs are still proving useful even though I'm not gigging at the moment. So I'll be hanging on to these cabs

[BassLine]

^ I'd gladly buy one if you had the itch to make them again..... but as you already said Pete - they take a long time to build, and I wouldn't feel right paying you sweatshop wages.

[Petebass]

Wow, Facebook reminded me today that the fiberglass cab build was 6 years ago! 6 years! Where does the time go? Feels like yesterday.

This cab itself is holding up beautifully, so any discussion about durability of fiberglass Vs wood is 200% settled.

[rommelmark]

Just finished a 42 liter sandwich cab with a deltalite 2512 and Fender Rumble 350 integrated at the back. 2 cm EXP foam with two layers of 350 gr/m2 of glasfibre with epoxy resin. Strong like hell and only 9.5 kg. Sounds brilliant. Thanks for all the information and discussions which helped a lot.

[Petebass]

Just finished a 42 liter sandwich cab with a deltalite 2512 and Fender Rumble 350 integrated at the back. 2 cm EXP foam with two layers of 350 gr/m2 of glasfibre with epoxy resin. Strong like hell and only 9.5 kg. Sounds brilliant. Thanks for all the information and discussions which helped a lot.

Great stuff. Got any pics?

42L seems small for 2512, but thats the beauty of DIY - make it to your own tastes.

[rommelmark]

My son (17 years old, but more than 6 ft tall) was fed up carrying a heavy 1x12 cab and an amp to rehearsals 3 times a week. He needed some power (one of the bands is a 20 people big band) and wanted a decent sound, lightweight, small and amp integrated. He plays 4 sting bass, so 42L (compromise) should be and proved to be enough (it’s for rehearsals).
PS: I am preparing my next bass cab build. Seems XPS foam can be bended when heated. So round shapes are possible. Nice
Let's see if I am able to copy pictures into this message.

[rommelmark]

Few more photo's (all I have)

[NotTheFish]

Looks great mark !

[Petebass]

Looks great mark !

Agreed, top effort! Is that a Duratex coating? And did you add a grill?

[rommelmark]

The paint I used is Warnex (water based). Over here in The Netherlands its the most popular paint for cabs (dry in hours, fully firm and solid in 4 days, quite hard and strong). Most probably similar to duratex, but you almost can not get duretex over here in Europe. I used 1 lb of paint, after curing I estimate its something like 0.5 lb of dry paint.
The grill is already added, the 9.5 kg (21 lb) total weight is including the steel grill. But the grill needs rework: color is wrong (my son wants it bare metal or silver), I did not folded the edges (so it is to weak in the middle, ordered a bigger one already and will fold it myself), it is quite heavy (almost 1 lb) but I can not find something suitable in aluminium. Maybe it can be made of glassfibre? Building the cab was time consuming (but fun) and I spend about 200 USD on material (excluding speaker and amp).

[Petebass]

Ah yes, I've done the silver/metal grills in the past and quite like the "industrial" look it gives. What sort of steel is the grill? I suspect it's a mild steel. If so, bare metal will eventually start to rust, so I would be painting it silver to keep it looking nicer for longer. Stainless steel won't rust, but it's usually quite expensive, and much harder to work with and bend.

There's a few different ways to make the grill stronger in the middle. An alternative to bending the edges is to make a timber frame. I also put some rubber stoppers between the grill and front baffle. They stop the grill from bending inwards, but also one in each corner prevents the grill from making any rattling noises.

[noplanb]

I've used foam rubber (black) draught strip under grill edges to kill any buzzes.
Did you place a tube on the port?, or just have the port as is?

[rommelmark]

Finally ready with the grill. Very strong now. Mild steel, so painted the grill

Instead of making a timber frame, I started to make a sandwich frame. The idea was to weave a grill from glasfibre I have laying around. Did some tests, but it is not getting strong enough, keeps flexing like chewing gum. So I dropped this idea.

Cab survived its first gig yesterday :-)