Impedance Bass Reflex - check up Beyma 12B100R - diyAudio
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Old 16th October 2012, 06:41 PM   #1
jzagaja is offline jzagaja  Poland
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Default Impedance Bass Reflex - check up Beyma 12B100R

Below is a simulation and measurement of Beyma 12B100R in 2 cu. ft. bass reflex box tuned to 32Hz.
  • Can you comment differences?
  • How do you validate proper BR functioning?
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File Type: png Impedance_bass_reflex_12B100R.png (44.2 KB, 287 views)
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Old 16th October 2012, 08:15 PM   #2
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Looks like the actual box is tuned to 28Hz rather than 32Hz of the sim.
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Old 16th October 2012, 09:00 PM   #3
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Also looks like your driver has higher Qts than that what you simulated. Did you measure the driver or just use manufacturer specs?
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Old 16th October 2012, 09:14 PM   #4
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Real vs. manufacturer parameters. Real was measured at very low power - speaker coupled directly to soundcard.
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Old 16th October 2012, 09:25 PM   #5
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Well that is a close match, but a soundcard output would not be able to drive a speaker very well.

Your original problem may be due to vent and box losses being different to predicted.
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Old 16th October 2012, 09:36 PM   #6
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I did my best to seal the box.
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Old 16th October 2012, 10:02 PM   #7
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The measured impedance drops to 2 ohm at 200 Hz, that's very strange.
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Old 16th October 2012, 10:04 PM   #8
jzagaja is offline jzagaja  Poland
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Yes because this is a complete speaker with crossover and notch. It's ca. 2,8 Ohm.
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Old 16th October 2012, 10:18 PM   #9
Dissi is online now Dissi  Switzerland
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Then i would say everything is ok. The notch causes the asymmetry of the impedance peaks.
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Old 16th October 2012, 10:30 PM   #10
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Notch is centered at 300Hz.
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