Specifically speaking about this woofer;
Aurum Cantus AC-180F1D
But....generally speaking, I understand about using a .5 woofer in full range speakers.
How about having a small sealed DVC woofer like the one above.
Then placing an inductor in series to the second voice coil restricting it's response to say.....50hz and below.
I know the choke will be huge, but, technically speaking would it enable you to have lower response in the same size sealed enclosure at the expense of straight up sensitivity V.S. having the 2 voice coils in parallel?
Aurum Cantus AC-180F1D
But....generally speaking, I understand about using a .5 woofer in full range speakers.
How about having a small sealed DVC woofer like the one above.
Then placing an inductor in series to the second voice coil restricting it's response to say.....50hz and below.
I know the choke will be huge, but, technically speaking would it enable you to have lower response in the same size sealed enclosure at the expense of straight up sensitivity V.S. having the 2 voice coils in parallel?
My gut instinct is this will get you flatter response, but not reach a lower f3 than just using both coils. You are effectively reducing the power input above your 50hz point on one coil, but at a shallow slope.
I had that thought as well.
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 then a 6db LP slope combining with the 6db HP slope should create a flatter response around 70hz.
Then the additive boost at 50ish should hold the F3 out a bit more at the sacrifice of the 3db overall sensitivity of both VC's in parallel.....
Maybe I'm missing something....?
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 then a 6db LP slope combining with the 6db HP slope should create a flatter response around 70hz.
Then the additive boost at 50ish should hold the F3 out a bit more at the sacrifice of the 3db overall sensitivity of both VC's in parallel.....
Maybe I'm missing something....?
As the frequency decreases the two voice coils will be increasingly out of phase, second order would cause more phase shift
Thank You
I assume that in the instance of a .5 woofer the fact that the second driver is physically separate makes the difference.
I could see that on a single driver having 2 VC's partially out of phase might not be wise.
I assume that in the instance of a .5 woofer the fact that the second driver is physically separate makes the difference.
I could see that on a single driver having 2 VC's partially out of phase might not be wise.
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.
fwiw, there are many cabinet geometries that people enjoy which mangle the phase at least as badly as what you're proposing.
Thanks for the encouragement!
I may proceed with this thought experiment at some point once I clear my plate of more important projects.
I may proceed with this thought experiment at some point once I clear my plate of more important projects.
.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.
Similar concept but using 2 woofers instead of 2 VC's on a single woofer.
Gotcha, I can't see there being a difference as regards phase distortion, as Anthony says, may well not be noticeable
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.
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.
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.
Think about that.
B.
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.
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
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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