I'm using the driver below in a setup inspired by the Brio Trio. It's only 91.5 sensitive, but it is very nice sounding and very well made and if the graph is true, very accurate above 500hz. Me ears say it is. Incidentally, I'm using the Tang Band W5 below it to get a little bass (down to about 100 sealed) and it's also great.
Galaxy Audio S5N-8 5" Neodymium Full Range Driver 8 Ohm
Galaxy Audio S5N-8 5" Neodymium Full Range Driver 8 Ohm
Thanks Dave. I had a look at these and specs appear impressive. Relatively low sensitivity is not really an issue as I can expect 100dB from my 15" FP woofers - which gives me 8dB to play with BSC.
Now the other Dave and Cal have both mentioned that I should consider a driver smaller than 8" for better hf response and better dispertion. I do respect their vast experience and I am listening but here is the thing - one reason I am building a new system is to get more slam and volume compared to my maggie panels. I don't actually know how to calculate max SPL level output but I suspect that the woofers will have a much a higher max - I am worried about frying a smaller FR driver if i use the woofers to their full capability. Norman Bates raised this very issue in Post #6 of this thread.
So this is what I have done - I have caught up with HollowBoy last week and he has loaned me a selection of drivers from his collection (a Fostex, a SEAS and afew others). I have already received FP 15HP400 woofers and I am going to cut a test baffle this week and compare a few drivers.
I was perusing eBay and saw a pair of Day PS220 FR drivers for local pick up just nearby, at an attractive price. So I quickly bought these and I picked them up yesterday. Funnily enough, the seller played me his lounge room system which consists of MA Alpair 10.3 in a small slot loaded box - he told me that the plan for the box came came from the "Canadian outfit" - Planet10. Small world indeed. The Alpairs sounded nice, but as he himself pointed out, they are a 'bit soft' and I they would struggle with a pair of 15" woofers. One thing I thought about was placing 2 (or 3?) of these between the vertically mounted woofers. But this is moving away from the simplicity of my original approach.
The problem with eBay is that you see lots of other desireable kit, and I also bought a pair of Philips AD12202 (12" FR with whizzer cone). They won't be here for a few days. According to photos and description they are in eexcellent condition I hope that they are!. These went out of production in the early 80s but they have appear to have a great reputation and are still sought after for this type of application. So will be interested to try these out. If they sound good i may even get ambitious and remove dust cap and install a phase plug, maybe treat the paper cone. Or maybe that would destroy any resale value in what is a valuable vintage speaker.
So I need to get a baffle built and start testing. Thanks for all the feedback so far I will update later in the week.
Others may suggest more suitable software or run some sims for you. Hornresp is the simulator I know best, so, Hornresp I used. It may not model OB very well, but you can get at least ballpark figures by simulating very large closed boxes.
Among the smallest / most SPL limited drivers I loaned you is the Fostex 105WK. I plugged that driver's spec sheet values into HornResp (I set all the horn dimensions to zero, and simulated a 999 litre box). From the "Acoustical Power" output screen, I chose tools --> Filter Wizard, and plugged in a 500Hz 2nd order highpass. I then ran the simulation at high power, and found that you can pour 50watts into it, and the displacement will be < 0.5mm.
Simulating a pro 18" (an EV driver that I own + measured) in a 999 litre sealed box, and then setting the power to give the same SPL, it needed only 5 watts - but the sim shows 4mm displacement. If that 18" was moved to an open baffle, and a modest 3dB of low frequency boost given, its displacement would ~double to 8mm - probably well past the Xmax.
...so it looks to me as if a fairly lightweight 4" crossed at 500Hz could keep up with a pretty large OB woofer.
Re: the Galaxy Audio S5N-8
That driver was recommended to me about a year ago. It does look good in some ways (mostly the small magnet - it should have less frame & motor reflections than the drivers I loaned you).
However, the Parts Express SPL plot (not the official spec sheet) shows roughly the same ~7kHz peak that the Fostex 105WK has, and doesn't (on paper) seem to outperform the (kinda average) Fostex driver.
I don't like it when manufacturers fudge or lie in their specs. I didn't take a punt on it. Of course, your hearing / experience / taste may vary.
This is an approach I've considered, but I'd not want to have a short array of drivers all playing > 10kHz.
Therefore I think, if I ever try this, that I'll go for 2-4 cheapish, high Xmax, ~87dB midbass drivers lowpassed at (maybe) 2kHz, and a single, more efficient full range driver playing higher, rather than a plurality of (relatively costly) full range drivers.
The Alpair drivers, or at least some of them, have 3rd party measurements that don't look as rosy as the manufacturer's specs. This 10P has 10dB more on-axis variance than the spec sheet, and "something really is going wrong at 550 Hz". I don't like it when manufacturers fudge or lie in their specs.
Markaudio Alpair-10P Paper Cone 6" Full Range
Mark Audio Alpair 10P-A Fullrange Loudspeaker Measurements Data and Information Full Range
This calculator does the same thing (and only one thing), a lot faster.
Piston Excursion calculator
it tells me that:
-a 4" moving 0.5mm at 500Hz gives 105dB
-an 18" moving 3.8mm at 40Hz gives 105dB
'assuming a sealed box or infinite baffle alignment'
Piston Excursion calculator
it tells me that:
-a 4" moving 0.5mm at 500Hz gives 105dB
-an 18" moving 3.8mm at 40Hz gives 105dB
'assuming a sealed box or infinite baffle alignment'
I appreciate the input I got from a lot of really helpful forum members so I want to take time to let you know where I finished up before I close this thread ...
Hollowboy advised me that Total Recoil, a local speaker repair shop in Melbourne, make wide range drivers. So I went down there there and I finished up buying a pair. See attached pics. They are 8" drivers, with pressed steel frame, whizzer cone, phase plug, and ferrite magnet. I saw a pair in the shop with long wool fibres wrapped around the whizzer (I think that this is called the 99c Lowther mod??) but Boyd of Total Recoil says that this has been superseded by a ring of felt bonded directly to the main cone directly underneath the whizzer. Their is also a ring of felt on the rear side of the main cone, just inside the suspension.
I have built one OB speaker, Other is 50% complete, and swill create a thread in the full range forum to describe my OB project.
Hollowboy advised me that Total Recoil, a local speaker repair shop in Melbourne, make wide range drivers. So I went down there there and I finished up buying a pair. See attached pics. They are 8" drivers, with pressed steel frame, whizzer cone, phase plug, and ferrite magnet. I saw a pair in the shop with long wool fibres wrapped around the whizzer (I think that this is called the 99c Lowther mod??) but Boyd of Total Recoil says that this has been superseded by a ring of felt bonded directly to the main cone directly underneath the whizzer. Their is also a ring of felt on the rear side of the main cone, just inside the suspension.
I have built one OB speaker, Other is 50% complete, and swill create a thread in the full range forum to describe my OB project.
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