dvc has me all wound up

[Dave R]

I have a DVC woofer, which I would like to use in a computer sound system. I want to hook up one (stereo) channel to each voice coil. I made measurements for 3 cases, with results as follows:

Measurement 1 –
L/H and R/H voice coils wired in series
fs = 61.9 Hz
DCR = 7.43 ohms
Qms = 5.3
Qes = 0.87
Qts = 0.75
Le = 1.43 mH
SPL = 87.2 dB
BL = 7.1 T*m
Mms = 15.25 g
Vas = 12.3 liters


Measurement 2 –
R/H voice coil measured,
L/H v.c. shorted out
fs = 61.9
DCR = 3.55 ohms
Qms = 1.43
Qes = 1.72
Qts = 0.78
Le = 0.20 mH
SPL = 84.2 dB
BL = 3.5 T*m
Mms = 15.25 g
Vas = 12.3 liters


Measurement 3 –
R/H voice coil measured,
L/H v.c. left open
fs = 62.6
DCR = 3.55 ohms
Qms = 5.3
Qes = 1.60
Qts = 1.23
Le = 0.38 mH
SPL = 84.8 dB
BL = 3.6 T*m
Mms = 15.25 g
Vas = 12.6 liters

What puzzles me is the big difference in the Q's and the Le, for measurements 2 and 3.

I suppose the fact that there is a measured difference for shorted vs. open could allow the speaker builder to choose whichever configuration suits the design best. But at the same time, if only one configuration matches the actual performance when both coils are being used (each channel for stereo for example), then it would be good to know which one is more appropriate.

Does anyone have a good explanation for what is happening (suspect it is electromagnetic effect somehow)?

Which values should be used for designing a box and crossover?


Dave R
the 200% Norske

[Ron E]

Use measurement 1 or 2 for designing the box.

Do some searches on this board for DVC wiring, you will find a lot of information.

[Collo]

Conversions for DVC drivers

[Dave R]

thanks for all of the good info.

I guess it makes sense to use the "shorted" measurement. Looking at the measurement when the v.c.'s are hooked up in series, the Qts is close to the value for the shorted measurement.

Dave R