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WTB 15" or 18" high qt. drivers

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Moondog55

Moondog55

diyAudio Member
Joined 2007
When you find them let me know please, although I may not be able to afford them.
High efficiency and high Qts seem to be mutually incompatible. and published data specs always seem to pick the loudest part of the audio spectrum, where-as i would only be interested in the bottom 3 octaves at most
 
H

homemade

Member
Joined 2004
Closest thing I can find that meets the requirements is the Goldwood GW-1858. Published specs seem to be comfirmed by MJK on his site(qt & average db). Appear to be proven in use. I see several small magnet 15" & 18" drivers on ebay , but they have minimal specs and do not have a track record. I'll most likely use the Goldwoods if nothing else comes along
 
H

homemade

Member
Joined 2004
I did see some 12 clearance drivers at Partsexpress not to long ago. High qt , 89db? Would most likely work ,but I'm using them with 15" Hawthrone coax's and I would have to believe 2 15 alpha's or 18" Goldwoods would can give more output (w/shelving) down low?? Now 3 of those 12" might work , but parrallel imped is a concern.
 
H

homemade

Member
Joined 2004
found these on ebay;

Parameter Value Unit/Notes
Effective piston area (Sd) 873 cm2
Free air resonance (Fs) 34.9 Hz
DC resistance (Re) 7.7 ?
Mechanical Q factor (Qms) 5.97
Electrical Q factor (Qes) 0.91
Total Q factor (Qts) 0.79
Voice coil inductance (Le) 2.1 mH/milli-Henrys
Equivalent air volume (Vas) 288.5 Liters
Moving mass (Mms) 97.7 Grams/Mmd + air load mass
Suspension compliance (Cms) 213.42 µM/N/micro-Meters per Newton
Force factor (Bl) 13.42 Tm/Tesla-Meters
Sensitivity (SPLref) 96.5 dB/reference 8?/2.83Vrms

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=330302035388&ssPageName=ADME:X:RTQ:US:1123



Maybe you could model these?
 
C

CharlieLaub

Member
Joined 2007
audio.claub.net
Paid Member
increasing the Qts of a pro driver for OB use

I have been thinking about this problem myself lately: High efficiency (e.g. pro) drivers typically have very low Qts. I would like to build a chip-amp-powered open baffle speaker, so what to do?

Here is the "solution" that I came up with: increase the driver Qts by increasing the output impedance of the chip amp. You can increase the Q as high as you want with this technique, and there is NO POWER LOSS (although it will affect the chip amp gain). See the section called "Mixed Mode Feedback" on this web page:
Variable Amplifier Impedance

More here:
Effects Of Source Impedance on Loudspeakers

-Charlie
 
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