Hi Folks,
I have a Planet Audio FU18 subwoofer, which I believe is a clone of the old Cerwin Vega Stroker. It's a dual voice coil sub with a double stacked magnets, which I am told is similar to JBL's differential drive system. It's a very heavy driver, and is about 250mm deep.
Specs as measured by Dayton DATS are as follows
fs 39hz
re 4.14
Vas 142l
Qes 0.31
Qms 6.25
Le 1.13mH
Power handling is 1000w RMS with a 10mm xmax
Can someone suggest a good design for the sub, less than 400 litres (around 14 cu ft), that maximises efficiency between 40 and 120hz?
So far I have modelled the keystone sub, which looks good, but given plywood in my country is 2400mmx1200mm, I would need 3 sheets to build to the 26.5" design width. Another thought was to try it in a ROAR15 box (despite my recent negative experience with the ROAR12).
Please throw some ideas at me as to what design may suit this speaker.
I'm happy to tweak Hornresp and create an Autocad model from the Hornresp inputs, but don't really know what sort of alignment I should be starting with.
Thanks in advance!
I have a Planet Audio FU18 subwoofer, which I believe is a clone of the old Cerwin Vega Stroker. It's a dual voice coil sub with a double stacked magnets, which I am told is similar to JBL's differential drive system. It's a very heavy driver, and is about 250mm deep.
Specs as measured by Dayton DATS are as follows
fs 39hz
re 4.14
Vas 142l
Qes 0.31
Qms 6.25
Le 1.13mH
Power handling is 1000w RMS with a 10mm xmax
Can someone suggest a good design for the sub, less than 400 litres (around 14 cu ft), that maximises efficiency between 40 and 120hz?
So far I have modelled the keystone sub, which looks good, but given plywood in my country is 2400mmx1200mm, I would need 3 sheets to build to the 26.5" design width. Another thought was to try it in a ROAR15 box (despite my recent negative experience with the ROAR12).
Please throw some ideas at me as to what design may suit this speaker.
I'm happy to tweak Hornresp and create an Autocad model from the Hornresp inputs, but don't really know what sort of alignment I should be starting with.
Thanks in advance!
Ok, the site below maintained by LORDSANSUI have many many "cookbooks" in the form of parametric CAD designer templates where you can export the data to HORNRESP and model the 3D view of your cabinet inside FREECAD. it have a little bit of a steep learning curve, but once you get the hang of it
you will feel home.
https://freeloudspeakerplan.rf.gd/
another similar aproach is Brian Steele tempates also
see the site below.
https://www.diysubwoofers.org/sheets/
you will feel home.
https://freeloudspeakerplan.rf.gd/
another similar aproach is Brian Steele tempates also
see the site below.
https://www.diysubwoofers.org/sheets/
What to do with it depends largely upon what you intend to listen to through it.
PA use/rock/classical/home cinema? Deepest bass/highest average output/best fidelity?
PA use/rock/classical/home cinema? Deepest bass/highest average output/best fidelity?
I probably should have mentioned that I've been using Lord Sansui's website. So far I have gotten the best results with the MTB Manifold, C-sub and Splanar designs. The problem I have is that I don't know whether a design is only a few tweaks away from being ideal, or if it not the kind of design that will suit my woofer, regardless of how I tweak the original design. I was hoping someone mya be abke to look at the specs and say "that looks like a good fit for design x".
Live music, where I need the second harmonic of the lowest string on my bass reproduced (42hz) and recorded music that is generally real instruments (ie no synthesised bass).
Fidelity is not a huge concern, as I can tame a rough response with DSP. Maximum output starting at 40hz is the requirement.
The end game is one subwoofer than can do low end for my band in small rooms (up to 100 people), and provide low end for parties etc outside at my home.
The 250mm depth of your driver might be tight in the Keystone design, the BC18SW115 is 242mm (9.5") deep and is about 9mm to part "P". Finished volume is 15.53 cubic feet, about 440 liters.
XOC1's TH-18 design has similar frequency response and is about 420 liters.
https://www.diyaudio.com/community/threads/th-18-flat-to-35hz-xoc1s-design.190635/
Art
Unfortunately there is no best fit design for a driver. You can adjust all designs to a particular driver.
Other than the conventional law statement pick 2 from 3 I would suggest:
If you need more output and can accept narrow bandwidth you go for high order designs. They will achieve the range from 40Hz to 120hz.
If you need wider bandwidth go for direct radiator and its variant.
If you wanna a trade of from both, go Sealed Chamber with Horn.
Some designs might give you flatter response then others.
As you saw with MTD-Manifold, some designs are easier to build them others, access panel is not something I like but maybe others like. In this sense you can count with FreeCAD how many panels a particular design have.
Some designs waste more internal space them others, panels, folding, bracing and so on, so acoustically you have less real volume to use.
If your driver is old and the cone is not reinforced, avoid use high compression ratio on it if the design you choose have this indication. It may reduces life or increase distortion.
Other than the conventional law statement pick 2 from 3 I would suggest:
If you need more output and can accept narrow bandwidth you go for high order designs. They will achieve the range from 40Hz to 120hz.
If you need wider bandwidth go for direct radiator and its variant.
If you wanna a trade of from both, go Sealed Chamber with Horn.
Some designs might give you flatter response then others.
As you saw with MTD-Manifold, some designs are easier to build them others, access panel is not something I like but maybe others like. In this sense you can count with FreeCAD how many panels a particular design have.
Some designs waste more internal space them others, panels, folding, bracing and so on, so acoustically you have less real volume to use.
If your driver is old and the cone is not reinforced, avoid use high compression ratio on it if the design you choose have this indication. It may reduces life or increase distortion.