A Victim of My Own Arrogance (Or: PA130 Revisited)
I posted a while back with questions regarding the Dayton PA130 and whether it could be substituted into an existing and popular design. I got a few responses, but not what I was looking for, so I decided to go out on my own (first mistake). I modelled a double-chamber vented design (second mistake) and came up WAY short. I tried using very long and narrow ports in an attempt to emulate a semi-aperiodic design (third mistake), but ended up with no low end and slow, distorted high bass. In trying to salvage the enclosures, different combinations of polyfill, foam, and felt were employed to no success. BSC brought in some bass, but blew the sensitivety and power handling. I know that these are only 5 inches, but I've gotten suprising results with a number of Tang Band 3 and 4 inchers. They were, of course, in traditional and easily modelled enclosures. BTW, from the third octave up, these are formidable drivers for the money.
I had high hopes for this cheap driver, and I know it's only one attempt, but I need guidance. The specs are almost on top as those of the Fostex FE107, so if anybody out there has had success with them, please let me know! Also, I'll beg the question about doubling these again- will two PA130s combined act like they have the T/S parameters of one FE127 (two drivers summing up to twice the Vas)? I'll jump all over the PAWO or Mileva based solely on my love of the monolithic appearance, plus I can be the first kid on my block to do it in a dipole. Or, am I better off with a simple (less terminally unique) bass-reflex to get a better idea of their capability, if any? Phase plugs, cone treatment, unusual cabinet... could be a $15 hero. Or not.
Thanks in advance, guys. I appreciate any input / speculation / laughing criticism.
* Power handling: 50 watts RMS/100 watts max
* Voice coil diameter: 1"
* Nominal impedance: 8 ohms
* Re: 7.1 ohms
* Frequency range: 90-15,000 Hz
* Magnet Weight: 20 oz.
* Fs: 84.1 Hz
* SPL: 90.0 dB 2.83V/1m
* Vas: .15 cu.ft.
* Qms: 3.65
* Qes: .53
* Qts: .46
* Xmax: 1.5 mm
* Net weight: 3.0 lbs.
* Dimensions: Overall Diameter: 5-1/4", Cutout Diameter: 4-1/2", Mounting Depth: 2-1/2", Magnet Diameter: 4", Magnet Height: 1-1/16".
"BTW, from the third octave up, these are formidable drivers for the money."
Do you mean the Dayton's or the Tang Band's?
For $15 the Dayton driver is probably something worth designing a good box for if they do perform as well as some of the cheaper Fostex drivers. If i could get the Parts Express website to open faster i would like to take a look at the driver. Is anyone else having trouble with the PE site being slow?
I will look at WinISD and see about a simple ported box for these.
How about a BiB? Nice, simple build just to see if they're worth messing with.
So anyway, I see the PA130 as a more rugged, drop in replacement for the Pioneer A11 which I and many others have used in a BiB. I've build floor loaded ones with about 102" line length which they had trouble driving. Gychang and others have use the original suggestion of 120", normal loaded, which was generally described as effortless sounding. I have also seen a set of DiYer measured T/S parameters for the A11 which had the Fs way up over 100Hz instead of the 70Hz (I think) that the PE site lists for them, so its hard to say where to tune an enclosure without being able to test the drivers yourself.
Lets assume it can drive a BiB at least as long as a Pio A11. That gives you:
line length = 120"
mouth area = 33"^2
zDriver = 26"
enclosure Vb = 32.2 l
I'm willing to bet, though, that it wouldn't stretch things too far build BiBs for the PA130 from mostly stock, 6' lumber giving:
line length = 144"
mouth area = 27.25"^2
zDriver = 31.25"
enclosure Vb = 32.2 l
If the PA130 sounds better than the A11, then I think it would replace the Pioneer unit as the cheapest unit you'd want to go for in a BiB with some decent bass.
It's been awhile, but I believe it's Max Andrews over at the P.E. list that did something with that driver and had good results.
I see it as having potential and lurking here and there have seen a few guys doing things with it.
Were it not for too many projects going I'd be serious over it as well.
Thanks for the responses, guys.
Caferacer- I meant the Daytons. Not spectacular sound, but above average.
Godzilla- I modelled simple ported boxes using WinISD. In fact, I modelled complicated ported boxes; probably my downfall.
Kensai- I keep coming back to the BiB as well for simplicity of construction and potential for higher bass output. Placing these close enough to a wall might be a little too difficult in my case, though. As for the PA130 sounding better than the A11, I cannot say having not heard the Pioneer. Based upon the good feedback on the 4", I can assume these may be competitors for bottom dollar champs.
Bluto- I can't remember exactly who it was, but someone did have a successful design, an MTM. I would simply take my cues from that and call it a day, were it not for my new found fascination with fullrangers.
Again, can anyone attest to the idea of doubling the drivers and in turn doubling the Vas, to facilitate going into the PAWO or Mileva?
Thanks again, all.
Right, Vas sums, so two drivers requires 2x the box volume (Vb) to have the same frequency response, though not having researched the various particulars I don't know how well a pair will work in the PAWO or Mileva.
You'll have combing issues unless you low pass one of them. Give you kind of a 1.5-way.
The BiBs I did with the Pioneers were floor loaded to the rear. In test and in their new homes they're sorta close to the wall, both sorta loading back into the same corner. They're not perfect, or even identical boxes (mouth openings ended up different somehow; I've got no real tools and I was a huge rush), but they've got tons of energy down to 50Hz, tailing into the low 40s. Running test tones, I was able to get a clean 20Hz tone. It was 18-20dB down, but clean, unlike trying to get such a tone out of my OB stuff. The BiB seems to keep them under decent control, and since the Pio only specs with an Xmax of 1.1mm and the Dayton is 1.5mm excursion shouldn't be an issue. Anyway, I think if you floor load them, you'll get plenty of bass for music without having them jammed into corners. Some folk running larger fullrangers, like Fostex have shown good results with normal top loaded BiBs pulled a couple feet away from any wall. If you're an HT nut and are going to demand high performance under 40Hz, you're going to need a sub regardless, so at that point it won't matter where you set these.
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