15" driver for Dipole sub

[Rudi]

I think I named this thread wrong. it should have been

15" driver for Dipole woofer

OK i have been playing with some design and doing a whole lot of reading and obviously getting 25hz (sub) is impossible but getting a good 40hz is very easy and then you get some good thirties

I looked at several 15" drivers from Paudio and the recomemdation from Martin, the HP15 reasonable Q and good SPL to work with when you want to tilt it

then one i tested with very good results is the 15C 500LF, although a really low Q it is easily solved. with a resitor and little bit of weight, i even had some headroom to add a LR circuit and a cap down to ground (i had to resist the other a bit more but it works great)

I am very happy with the performance so far and it integrates very well with the ribbon and 8"
I think there is something to be said about lower Q drivers. there is less of a smear on the bass. the downside is that you have to really cut it off very early and hope you have enough SPL to play with

[Timber_MG]

The Challenger is a really nice range of woofers with extensive shorting rings and very high grade components (priced reasonably as well). I use the C18-650EL for SR where it compares very well to woofers costing multiples.

[Rudi]

Good to hear you like the challenger range.

Just as a matter of interest. How do you find the HP15, have you used it before. The spec is very interesting and I would love to try one. But I bought to may 15” drives and would rather get rid of some of them before I buy more stuff . the price makes it very attractive and can make a very nice OB. Its curve is much better than the Visaton BGS40 so you will have better success rate with this driver in the nobox design

[Timber_MG]

I wouldn't if you're playing with a 500LF tbh (unless you mod the basket, live with a much, much smaller motor and intend to use it over a greater range). If you want to see linear, try the SN-15MB (I use them and they don't sound objectionable with even 1st order filters)...

They aren't the end-all of pro drivers, but the the money they're hard to beat, especially in SA.

[Rudi]

have you used them in OB. I've been wondering about the 47hz FS, isn't this a bit of a problem and the efficiency looks good to, specially at 30hz

how much better are they than the 500LF.

[Rudi]

Been working on a new design

shorter ribbon - or tweeter as shown
8" excel 22EX001 - (by the way did you see the new website)
SN15MB if 15C500LF

here is a few "rough" images. i have a contact that can bend and Laminate 16mm MDF so I am well away

Back will be open but coverd in cloth - as shown

[Timber_MG]

The SN15MB is a MID-bass driver btw that will satisty home users with a SET over its intended range. It doesn't really have what you're looking for here. I used it 150/180Hz-1kHz (or 700Hz) in the monster cinema speaker (where it mated to a pseudo-cardioid 18" for 60/70hZ-180Hz in a WMTMW setup.

I would look at a pro-driver with a good motor, real ~9mm+ Xmax and a well behaved stiff conical type paper cone (becasue you'll be crossing 200Hz max I presume). Have a look at 18Sound for starters from what is available in SA but also considder the B&C range (distributed by someone in Cpt iirc).

The P.Audio JBL 2226 clone (P series, not identical, higher inductance) is also a very well behaved driver (there are so many drivers to choose from, depends on your intended budget and LF requirements) but for an OB I would look at the Q.

For open baffle I would seriously not try and aim for a low-Xmax driver other than if you're content with low SPL. However most rooms suitable to open baffles would be rather larger and thus the power and excursion requirements rise drastically. I thought you're getting some high-Q 15s from the states?

[Rudi]

thanks for the feedback.

I am not worried about the SPL side of it. lets look at it differently - (it might horrify you) 84db at the very low end is more than enough

the crossover point is at 80hz. so you start rolling off at 40hz (huge choke and you need not equalize) at this point you are already more efficient that most hifi speakers add to that some baffle and you win some db again. the same with the 8" the baffle adds to its bottom end so you can have it almost linear ( the whole secret of the design is in the low crossover point, you get very clean bass.)

what is appealing of the SN15MB is that it is very good at 30hz (will have to do something with the 47Hz)

under most conditions the speaker isn't working very hard, not to much cone movement but I will look at the other suggestions

I've got some reservations regading the Augies (it is Ok for guys with SET amps - although it isn't efficient enough). I have a feeling it wouldn't sound as clean as I would like. you relying to much on mechanical dampening rather let the amplifier do that.

[Rudi]

had  look at the P150/2226 and it looks very good. medium Q. with a big choke it will be about 0.6-0.7 and a decent voice coil again will have to tame the 47hz FS and the advantage is that can be rolled of a bit higher

[Timber_MG]

The SN-15MB is not a bass driver meant to be crossed at 80. Even moderate volumes on an open baffle require considerable cone movement, unless one leaves most of the EQ out of the equation and goes for an extremely bass-light system.

If you're sharing a panel I would seriously considder using a higher x-o than 80Hz. It will put much fewer constraints on your midrange and overall system design.

The 15MB has an Fs ~50Hz, you will be hard-pressed to get much out of it below that (I know this woofer very well, without an acoustical load it drops like a stone, even 50Hz requires fairly radical EQ). It is exceedingly good for use as a mid-bass or even midrange (yes a midrange 15", it is better behaved than certain large vc drivers you may be aware of.

The 15MB has a very light curvi-linear cone (I'd not add mass to it). What you're looking for is a traditional woofer with a thick(and heavy), conical paper cone and a large Xmax (also due to motor geometry yielding higher Q.

I'd not be affraid to look over the pond either.