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Second Voice Coil For Bass Boost
Second Voice Coil For Bass Boost
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Old 16th June 2018, 08:16 PM   #11
anthonybisset is offline anthonybisset  Japan
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Nice thought experiment. Seems easy enough to implement. Some accuracy is sacrificed however it's hard to say if it would really sound bad or not. "Good" is incredibly subjective, especially with bass reproduction. Given the desire for small volume enclosure it might be worth the trade off. In the interest of exploration, I say push forward if you like experimenting.

fwiw, there are many cabinet geometries that people enjoy which mangle the phase at least as badly as what you're proposing.
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Old 16th June 2018, 08:27 PM   #12
Einric is offline Einric  United States
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Second Voice Coil For Bass Boost
Thanks for the encouragement!
I may proceed with this thought experiment at some point once I clear my plate of more important projects.
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Old 16th June 2018, 08:28 PM   #13
Einric is offline Einric  United States
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Second Voice Coil For Bass Boost
.5 Woofer as in adding a second woofer to a 2way but rolling off the second woofer to compensate for baffle step losses.
Similar concept but using 2 woofers instead of 2 VC's on a single woofer.
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Old 16th June 2018, 08:33 PM   #14
scottjoplin is offline scottjoplin  Wales
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Gotcha, I can't see there being a difference as regards phase distortion, as Anthony says, may well not be noticeable
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Old 16th June 2018, 09:03 PM   #15
tsmith1315 is online now tsmith1315  United States
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Quote:
Originally Posted by Einric View Post
However, if the natural F3 sealed of a single VC is 70hz and you add in the second VC at 1/2 octave below that around 50hz or so

Maybe I'm missing something....?
Quote:
Originally Posted by scottjoplin View Post
The phase shift
And the change in driver Q if your filter knee is this low.
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Old 16th June 2018, 09:52 PM   #16
JMFahey is offline JMFahey  Argentina
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Short answer: it won´t do what you want.

It won+t "go lower" by any means: 2 boxes same size, same speakers, will sound the same, have same resonant frequency, rolloff the same, just will sound louder (but at same frequencies as before) because of acoustic cross coupling and plain old pulling more power out of your amp simply because halved impedance.

"Cheating" by making the crossover frequency lower than the rolloff point won´t help much, if at all , because you are helping a weakened speaker (at that lower frequency) with another equally weakened speaker, so ....

There was an old proverb about "the blind leading the blind" .... some variation might apply here.

If anything, try putting your original speaker inside a doubled volume cabinet and see where that leads you.

After all, you *already* accepted a second cabinet.
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Old 16th June 2018, 11:29 PM   #17
bentoronto is offline bentoronto  Canada
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Second Voice Coil For Bass Boost
With the output of an accelerometer stuck to the dust cap, you could direct it to the second voice coil as corrective motional feedback.

Think about that.

B.
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Old 18th June 2018, 01:36 AM   #18
Jared is offline Jared
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This thread has me pondering what value there might be from using a larger woofer as a passive radiator, and then wiring some passive components to the passive woofer to adjust the response / tuning of the passive radiator.
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Old 20th June 2018, 08:35 AM   #19
wolf_teeth is offline wolf_teeth  United States
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Jared, look up the Sonus Faber Extrema version 2. That has an active coil PR with resistance across it.

As to the X.5 method with a DVC driver, Focal used to have kits like that in a 2-way. In terms of subwoofers, you'd get the +6dB below the Fc of the coil, just like in BSC, where the bass range halves the impedance. However, the Fc of the coil if low enough can cause an additional boost in combo with the driver's Fs. You might even get more output than expected, but the DVC will still only have the same Fs and Mms. It's likely more output can be put in a certain range if required, but actually going lower really can't be done unless changing the box or trying the 3rd order sealed response, or going with active means of some sort.

Later,
Wolf
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