I uncovered from storage a very nice pair of Pyle model W820 8" woofers. Would they work in a One Pi alignment? I have enclosed factory specs. I am not sure of the upper limit of these drivers, but they sound very decent even unenclosed.

W820
Fs = 56 Hz
Vas = 1.27 cu.ft.
Qts = .481
Qms = 7.839
Qes = .512
Zmin = 6.80
SPL = 92.6 dB
Xmax = .125"

Vented
Vb = .75 cu.ft.
Port Diameter = 3 inch
Port length = 4 inch
Fb = 56 Hz

Sealed
Vb = .75 cu.ft.
Fc = 89 hz

What would you do for "crossover"? What size box and port?

Many thanks,
BobCat

Also, Pyle had sheets of suggested boxes... but I find running the numbers through BoxPlot gives more and better possibilities.

Oh, to interpret those numbers, W820... the W series was a pro audio woofer, and 820...8" dia with a 20 oz magnet.

Internal volume = 0.65 cubic feet
Port diameter = 1.4 inches
Port length = 1.5 inches

I've calculated some volume offsets using CSG:

Woofer - 47.5 cubic inches
Cone - 8" dia, 2" long - 33.5 cubic inches
Cylinder (magnet) - 3" dia, 2" long - 14 cubic inches

Tweeter - 5 cubic inches
Cone - 3" dia, 2" long

Port - 2.5 cubic inches

1" Fiberglass insulation (calculated at 1/4 thickness, to compensate for compression volume)
Side - 16" x 7" x 0.25" - 28 cubic inches
Bottom - 10" x 7" x 0.25 - 17.5 cubic inches
Back - 16" x 10" x 0.25" - 40 cubic inches

Total displacement: 188 cubic inches (Enter into one of the offset fields, either LFD or "other")

Internal cabinet dimensions:

Height - 16.4 inches
Width - 10.9 inches
Depth - 7.3 inches

I would reccomend 5/8" wood stock, so add 5/8th inch twice, or 1.25 inches to each dimension. (Enter 1.25 into the "wood size" field)

Final analysis:

Height - 17 5/8"
Width - 12 3/16"
Depth - 8 1/2"

Port is 1.4" diameter and 1.5" long. You may substitute a 1 1/2" diameter port that's 2" long since 1.4" diameter (1 7/16ths) will be hard to find.

Let us know how your speaker sounds. It looks like it will probably work out very nicely!

The other sheet, filled out by hand, from Pyle, lists suggested box sizes, sometimes both ported and sealed are give. Also suggested LxWxD. Port sizes are given. These are sort of cookbook style practical size boxes.

I found Pyle, at that time, very good about sending response graphs and any other data I asked for. Also answering application questions.

While much of their line does not meet my needs (mostly car stereo now) their pro audio line of PYMxxxx series of woofers are excellent, economical woofers. About the same bang for the buck as the Eminence woofers. But I find the Pyles many times yield good performance in better sized boxes than most of the Eminence woofers. Perhaps I put too much stress on box sizes I can move around (portable PA gear).

Fs = 44.1 hz
Re = 6.29 ohms
Z ohms @ 400 hz = 7.3 ohms
Zmin = 7.1 ohms @ 289 hz
Qms = 9.422
Qes = .345
Qts = .333
X lin = .150"
Vas = 1.7 cu ft
Pe = 70 Watts RMS
SPL = 95 db/wt/mt

Another chart received at the same time recommends:

Sealed enclosure .5 cu ft
Ported enclosure 1.1 cu ft w/ port = 2.5" dia x 1.5" long

Hope this info helps.

Paul