ANOTHER friend of mine recently asked about building a dual 15 sub similar to the NEXO RS15. (hundreds of miles away....) 
thankfully I'd put some work into this already. He didnt want to curve the ports and couldnt go wider than 43, so I was pretty much stuck with a pair of 3" wide ports.
95 liter chambers ( after driver, port, and brace displacement) loading with 15tbw100, OR faital pro 1030 HP. should have more output than its nexo counterpart (15ndl76) although slightly higher port compression due to restricted port area (305cm sq per driver).
thankfully I'd put some work into this already. He didnt want to curve the ports and couldnt go wider than 43, so I was pretty much stuck with a pair of 3" wide ports.
95 liter chambers ( after driver, port, and brace displacement) loading with 15tbw100, OR faital pro 1030 HP. should have more output than its nexo counterpart (15ndl76) although slightly higher port compression due to restricted port area (305cm sq per driver).
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Very nice work, Sine143. You definitely have the Google SketchUP thing down. It looks like you have some solid carpentry skills too.
If you ever want to attempt the curved ports, check out this video for some ideas:
Building the Subwoofers @ Sulamita Part 1 - YouTube
A while back I was researching some more high-tech slot port designs and came across that video. I thought I had also bookmarked some drawings for the Nexo sub but I can't find them right now. If they turn up I will pass them on.
If you ever want to attempt the curved ports, check out this video for some ideas:
Building the Subwoofers @ Sulamita Part 1 - YouTube
A while back I was researching some more high-tech slot port designs and came across that video. I thought I had also bookmarked some drawings for the Nexo sub but I can't find them right now. If they turn up I will pass them on.
Nice video, but a bit of a rookie "mistake" in there, particularly considering that the woofer baffle is recessed. Always cut the holes for the drivers before bonding the baffle that would be holding them to the rest of the box. The day your router slips, or something else turns your hole-cutting into holey hell, you'll understand
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almoooost there on box1
I likey.
FWIW, I've had better results combating panel flex by using diagonal cross-braces, rather than ones that are parallel to any of the edges. Not sure about the reason why...
thanks for that tip. This is actually the first BR I've ever designed/had built so... you live and learn haha.
he still needs to add the "Window Pane" bracing to each chamber, which should help stiffen everything up.
he makes me feel bad about the progress on my THs... he did all this work today! grante its all 90 degree cuts.... and I'm still waiting on my drivers....
he still needs to add the "Window Pane" bracing to each chamber, which should help stiffen everything up.
he makes me feel bad about the progress on my THs... he did all this work today! grante its all 90 degree cuts.... and I'm still waiting on my drivers....
Nice boxes! Also Faital Pro 15HP1030P is the cheaper ceramic version of the 15HP1060P correct? 95 litres is the same as the internal volume of my 3012lf box (although the 204 sq cm of port area on it is probably too low when you feed that driver max power).
I've found those Faitals in simulations to be very similar to the 3012lf in response in a lot of cabs.
(I do mean the 3012lf, the 3015lf needs about twice the box volume, but only half the amp power for the same SPL, until it hits its lower Xmax limit).
So I'm assuming if you're using a ~40Hz tune, you're getting about 130dB output (2pi) with around 80 Volts (parallel woofers)? Or am I jumping the gun?
Now the only other thing I was going to suggest on those boxes was a couple of braces connecting the H to the back of the box in the centre. Using 18mm ply they are probably more than stiff enough, but see my crude paint picture for an example.
I've found those Faitals in simulations to be very similar to the 3012lf in response in a lot of cabs.
(I do mean the 3012lf, the 3015lf needs about twice the box volume, but only half the amp power for the same SPL, until it hits its lower Xmax limit).
So I'm assuming if you're using a ~40Hz tune, you're getting about 130dB output (2pi) with around 80 Volts (parallel woofers)? Or am I jumping the gun?
Now the only other thing I was going to suggest on those boxes was a couple of braces connecting the H to the back of the box in the centre. Using 18mm ply they are probably more than stiff enough, but see my crude paint picture for an example.
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yes the 1030 is the ceramic equivalent of the 1060. clocks in at 26lbs vs 15.7.
it has a low vas, representative of the current trend in italian designed woofers (Strong motor, stiff suspension, results in lots of bass in a small box)
lets just say I can easily bottom out a 3015lf with 1 finger pushing, and it takes 2 hand to get the faital to move any significant amount (cant get the vc to reach the backplate).
Yes, its tuned to 38 (as box size is slightly larger than vas after bracing and driver volume is accounted for). 80v is exceeding the long term thermal limit so it will likely only get about 70 v. port size could have been a bit larger, but we'll see.
it has a low vas, representative of the current trend in italian designed woofers (Strong motor, stiff suspension, results in lots of bass in a small box)
lets just say I can easily bottom out a 3015lf with 1 finger pushing, and it takes 2 hand to get the faital to move any significant amount (cant get the vc to reach the backplate).
Yes, its tuned to 38 (as box size is slightly larger than vas after bracing and driver volume is accounted for). 80v is exceeding the long term thermal limit so it will likely only get about 70 v. port size could have been a bit larger, but we'll see.
Based on a few comparisons, they are interchangeable with the Kappalite 3012lf, but give 6dB extra power handling via displacement. Basically the same as two pairs of isobaric 3012lf but cheaper.
I believe they should work quite well in narrow width T48 18 to 24 inches and also a half width version of Jim Bell's tapped horn, where as kappalites are king of the widest boxes and low compression designs.
Very wise though to lower the limits if you're playing a lot of sine wave music. The woofer can look fine but the coil is gradually heating up. The impedance is lowest at the tuning freq but higher up the passband it rises. This is another reason I design boxes to be slightly louder at tuning, especially as the woofer is barely moving there. I'm interested to see what other woofers Wayne Parham's Lab 12 cooling mod does.
I believe they should work quite well in narrow width T48 18 to 24 inches and also a half width version of Jim Bell's tapped horn, where as kappalites are king of the widest boxes and low compression designs.
Very wise though to lower the limits if you're playing a lot of sine wave music. The woofer can look fine but the coil is gradually heating up. The impedance is lowest at the tuning freq but higher up the passband it rises. This is another reason I design boxes to be slightly louder at tuning, especially as the woofer is barely moving there. I'm interested to see what other woofers Wayne Parham's Lab 12 cooling mod does.
I was thinking narrow width T48 only, in a 36" wide cab you'd want two or likely you'd have a spike around 'tuning' and less upper bass.
A 3015lf in an 18 inch T48 is likewise a poor match, being mostly upper bass with little low end.
And you're right it's actually around 2.1 - 2.2 faitals to the same box as a kappalite. The 4 ohm version wants an even tinier box! I think the Vas is about 85 litres and the motor even stronger.
A 3015lf would want the whole of your double 15 cab to itself, which would involves boarding up the other hole and cutting a hole in the divider.
The divider is a pretty good idea though in case one driver fails, the other will be protected. It's something I hadn't put much thought into as a double 18 version of my P-Audio BR cab would be 24 cubic feet external! Although with the help of corner loading, 136dB 1m to 30Hz, needing only an amp capable of 300 watts at 4 ohm and £220 worth of drivers gives it 'horn like' efficiency!
A 3015lf in an 18 inch T48 is likewise a poor match, being mostly upper bass with little low end.
And you're right it's actually around 2.1 - 2.2 faitals to the same box as a kappalite. The 4 ohm version wants an even tinier box! I think the Vas is about 85 litres and the motor even stronger.
A 3015lf would want the whole of your double 15 cab to itself, which would involves boarding up the other hole and cutting a hole in the divider.
The divider is a pretty good idea though in case one driver fails, the other will be protected. It's something I hadn't put much thought into as a double 18 version of my P-Audio BR cab would be 24 cubic feet external! Although with the help of corner loading, 136dB 1m to 30Hz, needing only an amp capable of 300 watts at 4 ohm and £220 worth of drivers gives it 'horn like' efficiency!
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