Custom DIY 2x15 cab build

[ko stradivarius]

Yes, 1/2” ply. You can see that it’s my first time using PL Premium by the way I used too much on the right side of the bracing on the back.
Ha ha. Oh well.

Other things I’ve learned:
*The Milescraft circle jig works pretty well. It was the first time I used a router.
*Cutting roundovers is messy!
*Kilz oil based primer(I used the brown can) works awesome as a base for Duratex. I had started using bondo to fix a couple of spots. The primer worked well to cover it after sanding the bondo.
*Duratex is fun to apply.

 

[3rdcurve]

I really want to try one of these builds with some Beyma 15WR400s. Nice build!

 

[takeout]

Those of you who've built with 3015s or 15PR400s - how are you guys deciding on tuning frequencies for these? I'm guessing the box volumes are all pretty similar?

 

[kraigo]

Search for Linear Team WinISD. It's very good for this kind of thing.

 

[ScottTunes]

Those of you who've built with 3015s or 15PR400s - how are you guys deciding on tuning frequencies for these? I'm guessing the box volumes are all pretty similar?

Eminence has box size recommendations that would make a good starting point. Then decide how you want to fine tune with porting via winISD, or Eminence's designer program (I use the latter).

I built a "small" sealed box for my 3015 pair. About the same size cab as JohnK_10's... Works and sounds great, even without the ports! I happen to prefer the sealed over ported design in this instance.

 

[takeout]

I've played around plenty with WinISD; I've also read a lot on here about how it's a decent blunt instrument, but probably not the best for really nailing a design for a particular driver/box combo.

It seems like the formula for success = either driver, in a box ~3.6 ft^3 or so, tuned to around 45Hz. ~7.3 ft^3 for a 2x15.

 

[BadExample]

I've played around plenty with WinISD; I've also read a lot on here about how it's a decent blunt instrument, but probably not the best for really nailing a design for a particular driver/box combo.

It seems like the formula for success = either driver, in a box ~3.6 ft^3 or so, tuned to around 45Hz. ~7.3 ft^3 for a 2x15.

These programs only predict the lower frequencies.

 

[kraigo]

I've played around plenty with WinISD; I've also read a lot on here about how it's a decent blunt instrument, but probably not the best for really nailing a design for a particular driver/box combo.

It seems like the formula for success = either driver, in a box ~3.6 ft^3 or so, tuned to around 45Hz. ~7.3 ft^3 for a 2x15.

I apologize if I was presumptuous. I think WinISD is fine for designing the low end of a box that isn't anything more esoteric than a ported or sealed box. I play around with it and a spreadsheet that helps me turn box volumes into dimensions until I like the dimensions, the response curve and the power handling.

 

[Milo Spleen]

SVT= 85lbs + 75lb 2x15 JBL cab= 160lbs
STM= 6.5lbs + 46.5lb 3015 cab= 53lbs.

Hmmm. My 64 year old back is smiling.

 

[BadExample]

I apologize if I was presumptuous. I think WinISD is fine for designing the low end of a box that isn't anything more esoteric than a ported or sealed box. I play around with it and a spreadsheet that helps me turn box volumes into dimensions until I like the dimensions, the response curve and the power handling.

I use an online geometry calculator to get the inner dimensions, some other program to get the outer and create a nice accurate cut list. Then I screw up one or two cuts and the box shrinks. That's why I do sealed cabs

 

[ko stradivarius]

Finally finished it. A local guy showed me that creasing the grill cloth across lines helps to keep it straight.

Yes I know it’s not an Ampeg but that’s just between the hundreds of us.

 

[ScottTunes]

Love the vintage Ampeg cloth!

 

[beans-on-toast]

A local guy showed me that creasing the grill cloth across lines helps to keep it straight.

Interesting. How did you go about creasing the cloth?

I’ve seen machines that roll and stretch the cloth to help even out stress in the weave.

 

[TAZ]

I've played around plenty with WinISD; I've also read a lot on here about how it's a decent blunt instrument, but probably not the best for really nailing a design for a particular driver/box combo.

It seems like the formula for success = either driver, in a box ~3.6 ft^3 or so, tuned to around 45Hz. ~7.3 ft^3 for a 2x15.

To continue on takeout's observations...

I built and gigged 2 115 cabs with 15PR400s with those parameters for the past 2 or 3 years. They sounded full with good range. It responded to boosting 40hz-100hz, 4khz easily. I ran several tube and several Class D heads through it for many gigs each and the cabs handles it. As expected some heads mated better than others but nothing a preamp pedal couldn't cure. Late last year, I had a new perception that the tone sounded a little diffused. I sawed the cab down, added more bracing and reduced the internal volume to apprx. 2.95 cu.ft. and tuning at ~47hz. The cabinet came alive, present and fast with more punch. Ironically, I looked at the GB Bassic dimensions, after the fact, and they are about the same. I've recently added a tweeter with HPF at 3.5khz. Been gigging it for the past couple of month and pleased in how it responds tonally through the frequencies.

Lastly, I use 5 string basses / low B. The cab's dimensions are: o/d 24"x19"x14.5", slot port, 1/2" Baltic Birch ply, cloth grill, total weight 42lbs.

 

[takeout]

To continue on takeout's observations...

I built and gigged 2 115 cabs with 15PR400s with those parameters for the past 2 or 3 years. They sounded full with good range. It responded to boosting 40hz-100hz, 4khz easily. I ran several tube and several Class D heads through it for many gigs each and the cabs handles it. As expected some heads mated better than others but nothing a preamp pedal couldn't cure. Late last year, I had a new perception that the tone sounded a little diffused. I sawed the cab down, added more bracing and reduced the internal volume to apprx. 2.95 cu.ft. and tuning at ~47hz. The cabinet came alive, present and fast with more punch. Ironically, I looked at the GB Bassic dimensions, after the fact, and they are about the same. I've recently added a tweeter with HPF at 3.5khz. Been gigging it for the past couple of month and pleased in how it responds tonally through the frequencies.

Lastly, I use 5 string basses / low B. The cab's dimensions are: o/d 24"x19"x14.5", slot port, 1/2" Baltic Birch ply, cloth grill, total weight 42lbs.

GREAT feedback. Thanks for responding with your experience!

 

[ko stradivarius]

Interesting. How did you go about creasing the cloth?

I’ve seen machines that roll and stretch the cloth to help even out stress in the weave.

Just simply by hand. I lined up the cloth and just picked a line then carefully creased it. I did the top and a side. I started in one corner then stretched to the opposite side and picked another line in the cloth to use for alignment, then just worked my way around. The Pre-creasing helped to keep everything aligned while stapling. It worked out fine the first go.

 

[ko stradivarius]

I made a dolly out of the scrap and some hardware I had.
I’m done with building things for a while. I need to work on my house!

 

[beans-on-toast]

Just simply by hand. I lined up the cloth and just picked a line then carefully creased it. I did the top and a side. I started in one corner then stretched to the opposite side and picked another line in the cloth to use for alignment, then just worked my way around. The Pre-creasing helped to keep everything aligned while stapling. It worked out fine the first go.

Thanks for the explanation. Grille cloths like this one are not easy to do. It came out very well.

 

[xk49w]

Is that a Macintosh SE/30?

 

[ko stradivarius]

Ha ha! Yup. I have the keyboard and number pad in a box somewhere too.
I have a Mac II fish tank on the other side of the Genz box. The SE30 was going the way of a fish tank but I never got around to it in in the last 20 years.