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PEARL PR-2 8" woofer (note:
PEARL's web-site is still pretty sparse)
These are very rare
unique hand built bass drivers in Calgary by Bill Perkins. The picture above is of
the larger magnet version. The basket, motor structure is designed so that a bolt
can go thru the pole piece and attach the speaker to the enclosure. I plan to take
advantage of this to bolt the speakers together. That, the massive baskets, steel
rod beween the respective bolt holes, and a small, rigid enclosure should go a long
way towards realizing the full potential for push-push loading to cancel the Newtonian
effects of the moving cone. They will load a TL.
The 4 units I have
are older, superceeded small magnet version -- the olny reason I was able to get
them was because they were surplus.
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A
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B
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C
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D
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Average
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Electrical/Mechanical Parameters
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Revc
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(DC VC Res ) |
3.6
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3.6
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3.6
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3.6
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3.6
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Ohm |
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Fo
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(Res Freq ) |
31.3
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30.4
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29.5
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26.6
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29.5
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Hz |
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Zo
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(Zmax at Fo) |
36.4
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39.6
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45.5
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67.7
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Ohm |
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Sd
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(Piston Area) |
0.02
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0.02
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0.02
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0.02
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0.02
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sqM |
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BL
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(Flux x Length) |
6.8
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7.1
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8.4
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8.5
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TM |
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no
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(Ref Effncy) |
0.65
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0.72
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0.87
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0.78
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% |
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SPLo
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(SPL at 1W ) |
90.2
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90.6
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91.4
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90.9
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dB |
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Qms
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(Mech Q) |
2.93
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2.82
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2.46
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3.52
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Qes
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(Elec Q) |
0.322
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0.282
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0.212
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0.198
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Qts
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(Total Q) |
0.290
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0.256
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0.195
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0.187
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0.232
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Vas
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(Acous Vol) |
70.5
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74.9
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74.1
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85.0
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76.1
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Litre |
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Cms
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(Compliance) |
1242.0
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1319.0
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1305.4
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1496.8
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uM/N |
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Mms
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(Total Mass) |
20.8
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20.8
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22.3
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24.0
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Gram |
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Mmd
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(DiaphmMass) |
19.2
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19.2
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20.7
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22.4
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Gram |
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Motor Impedance Parameters
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Levc
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(Induc at 1kHz) |
0.90
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0.850
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0.75
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0.74
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mH |
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Levc
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(Induc at 20kHz) |
0.36
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0.35
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0.32
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0.32
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mH |
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Krm
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(Resistance Cons) |
9.9
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6.7
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4.5
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6.0
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mOhm |
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Kxm
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(Reactance Cons) |
12.7
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11.2
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9.1
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8.8
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mH |
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Rem
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(Res at 1kHz) |
3.4
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3.0
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2.7
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2.7
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Ohm |
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Rem
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(Res at 20kHz) |
24.7
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24.5
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24.2
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22.3
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Ohm |
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Erm
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(Resis Expont) |
0.67
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0.70
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0.73
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0.70
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Exm
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(React Expont) |
0.70
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0.71
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0.71
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0.72
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Measurements by Aaron
Drabbitt
LMS Version 3.72 / Delta Mass Curve Pair / Mass Added to Cone = 16.00 Gram
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More info on the line
for these here.
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