Cubo 15

Hi. Asked a while back about PD 158's but got no response. Parameters are outside of the normal Cubo15 but would they be ok in extended ? Also got a pair of P-audio E15-350. Any thoughts ?. Have already built cubo 12's wirh rcf's and sound great. Can these be used together with cubo 15's without problems ? Plan to build in next couple of weeks. Cheers Mick

I don't know if the T/S-parameters have changed but based on the current parameters I would recommend Cubo 15 Extra Extended for the PD-158.

See also: www.freespeakerplans.com/kunena/38-hoste...o-15?start=390#20107

Best regards

Cubo

There's an "Extra" extended version ? Can't seem to locate plans for these. Also, is it ok to use 2 different drivers in cubo15's as 2 pairs ? Got the 158's and P-Audio N350's. Also got a pair of Kappa 15's. If so would you recommend 1 of each per side or same drivers together per side? Thanks

Hi Cubo, you refered to fane sovereign 15-500 in your previous reply. Just wanted to make sure there was no confusion as to which driver I have, I have the Sovereign PRO 15-500. These are the T/S

FS Hz 40 Hz
RE Ohms 5.4 O
Qms 10
Qes 0.33
Qts 0.32
Vas Ltr 192 litres
Vd litres 0.513 litres
CMS (mm/N) 0.186 mm/N
BL T/m 18.9 T/m
Mms (grms) 85 grams
Xmax (mm) 6 mm
Sd (cm2) 855 cm2
Efficiency % 3.60%
Le (1k Hz) 1.9 mH

Is cubo extended still the best enclosure? Apologies if this is the driver you refered to, but as there are two fane drivers with very similar names, I want to make sure we're talking about the right driver!!! Many thanks

TMH

I want to make sure we're talking about the right driver

Yes, we're both talking about the Pro-version.

Can't seem to locate plans for these

E-mail to questionsaboutcuboATgmailDOTcom

Also, is it ok to use 2 different drivers in cubo15's as 2 pairs ?

It's not ideal but it will work.

Also got a pair of Kappa 15's

The regular Kappa's are a bit short on Xmax, so mechanically they'll take about 300 W with a correct HP, whereas the Kappa 15LF will take around 500 W.

If so would you recommend 1 of each per side or same drivers together per side?

I would recommend that you'll try both and give your opinion about it.

Best regards

Cubo

Hi Mr Cubo, I don't know if anyone has asked this question before but, I thought it would be a good idea for
people thinking about building 215's? In my situation I was thinking about mounting the drivers with the magnets inside and I would wire them in parallel?


Which way would give the Highest SPL?

What is the best way to wire the drivers?

Would it make any difference to the SPL if one driver magnet was mounted inside and one outside?

Would it also make any difference to the SPL if they were out of phase? "push pull scenario"

Thanks,

Which way would give the Highest SPL?

Because of the specific T/S-parameters of the drivers that you're using I would use them with the magnet in the chamber. Coincedentally, this will also give the highest SPL.

What is the best way to wire the drivers?

Allright, let's settle this once and for all

You'll likely hear very little difference between normal or reverse wiring. I think you might be able to reveal a difference in an ABX-test but the difference is usually very small. If you would design a top cabinet with a 12" and a compression driver, in some cases you might actually have to wire the compression driver electrically reversed to get it acoustically in phase with the 12" depending on the specific filters you're using..
So it also depends on what loudspeaker cabinet/ driver you're using to cover the frequency range directly above.

As a rule of thumb use normal wiring, you can always try though.

Would it make any difference to the SPL if one driver magnet was mounted inside and one outside?

You would measure variations up to 1 dB in the frequency repsonse. Technically you're creating two slightly different cabinets, so the actual response will be the average of the two. Apart from push-pull configurations this is hardly used in other cabinet designs.

If you have a push-pull configuration one driver is wired out of phase, so the drivers are acoustically in phase. As the drivers movement is out of phase, so are most of the distortion products due too non-linear movement of the cone. The even order harmonics are reduced, the uneven order harmonics stay the same. Linear movement in drivers can be improved, which raises the cost, so lower quality drivers benefit the most, anything beyond is a personal matter imo.

However as the drivers are in two slightly different cabinets, the unlinear movement of the two drivers is also changed. This would make the push-pull configuration less effective. I suspect that the overall offset will still show an improvement but if that is worth it only you can decide.

Best regards

Cubo

While working on my two new Cubo18's this weekend I had a thought. Since the Cubo15 and Cubo18 dimensions are so similar, would there be any drawbacks to just use the same plan for both and then make an adapter to fit a 15" speaker in the 18" hole?

Build the Cubo18 as normal, then just cut out a circular piece of wood that mounts to the 18" screw holes with new screw holes and cutout for the 15" speaker. This way, it would be one plan to rule them all.

It will definately work, I've done similar things while building Cubo prototypes. I will do so in the future but the future in my case is best unspoken of untill it is there. I will give you credit though, it's a good idea. I do advise to use 15 or 18 mm Baltic Birch for the adapting Ring (pun intended).

Best regards

Cubo.

good day sir
am looke to build 2 cubo 15 for the dayton which version i need
www.parts-express.com/dayton-audio-pa385...-4-vc-8-ohm--295-040
thanks