12-15 inch pro woofer choice?

[phivates]

Brian Steele has looked closely at the PA-310-8

[lowmass]

Originally Posted by John Busch

A driver you may want to consider is the PE-PA-310-8 (12"). In 2.5 cu. ft. box tuned per thiele at its 39 Hz FS. 4" port dia X 7" long. 94.5 db/watt true net efficiency. $60. Reasonably flat to 1.8Khz. 5.5 mm X-max. Rugged construction with 80 oz of magnet. Nice thick plates. -3 in the above box is 39 Hz. Add a couple of inches to the port length and you will get -3 at 37 Hz. This assumes no RG value in the equation. Have used before. Very consistent and dynamic so far. YMMV.

That was actually the first driver I considered. No big peak around 2k and reasonable box.

My concern, and perhaps not well founded?, is its MMS. It looks like a cone that just had mass thrown at it to get a flatter response? I was a bit concerned as it was about 2X the MMS of a number of other 12" drivers.


What can U say to this fear? I don't have a good solid base for this but the few lower mass woofers Ive heard seem to have certain quality in the bass that I cant really define well although they have all been in big boxes.

[John Busch]

As the saying goes, no free lunch. 72G for a 12" is about average... and we are talking about a $60 woofer. If you are really out at 1 Khz (12 db/oct) you should be OK.

Or you can spend a couple of hundred bucks and get the MMS down a bit, but a bigger box for the same 37-39 hz cut off. It will be interesting to see what choice of driver you make.

[lowmass]

Yea this woofer will be used for some experiments mostly testing a tweeter in a dipole 3 way ( woofer to 200hz) and then in a wave guided 2 way monitor( woofer to 1khz). This will be some preliminary testing and wanted to spend a small amount for now and ramp up after some investigations.

BTW what mean here? "This assumes no RG value in the equation"

also any experience with the 15 and 18 " versions of that driver??

[John Busch]

Resistance Gain... this covers any resistance(s) added to the woofer (or any driver for that mater) usually due to crossover components such as inductors. Basically, any series resistance found between the woofer and amplifier. RG will increase the QTS of the driver and that can have an effect on box tuning and or size. And to some extent, net driver efficiency. Typical woofer RG runs from .25 ohms to as much as 2 ohms. The default value is usually .5 ohms. How is that for confusing the issue?

[mortron]

Much appreciation to the OP. Good topic.

Anyone have any quick thoughts on the Beyma SM115n?
What about the Beyma 12BR70?

I've seen recent mention of EBP, and have been using it to help me select possible drivers. It's interesting to see that you can get the 2/3 out of cheap, efficient, and low-end. You gotta pay to play, and I'm looking to just "dabble". Not so much achieve perfection as much as I want to cut my teeth on something that will give pleasing results without expecting too much. The two above drivers are different in a few ways and a compromise between those 3 variables I tend to notice.

[lowmass]

"resistance gain" yes ok wasn't sure. Ive been here in the past, mostly developing a dipole "sub" panel (not cones). Two big takeaways from that work were Mms and crossover resistance.

In the end I loved the lighter diaphragms mostly due to less shaking of the whole baffle under hard drive ha AND I ended up making my own inductors out of large gapped transformer cores and 10 gauge wire to make a real dent in the coils resistance. The low R coil was most noticed however with woof in box, not so much in the dipole.

[fullrage]

have anyone thought to use the beta 12 lta, from eminence, just a thought...

[ScottG]

Originally Posted by lowmass

Yea this woofer will be used for some experiments mostly testing a tweeter in a dipole 3 way..

You should be looking for drivers with higher Qts.. (..and not to large of a Vas.)

OR

Looking for something with a LOT of efficiency near 150 Hz and then adding resistance (usually in combination with inductance).

You can often linearize a choppy higher freq. response with a damping compound on the surround and cone junction. (..usually several coats of stretch fabric glue.)

[ScottG]

Originally Posted by fullrage

have anyone thought to use the beta 12 lta, from eminence, just a thought...

Yes, but the Fane I posted earlier is typically preferred (..if you can get it).