It's another odd, basic question from me. If there is a correlation between cone area and bass response why do subwoofers have flatter cones?
The issue seems to be particularly relevant to small subwoofers. If you have a flatish 4" sub with a huge Xmax you've probably got 3" of cone (7 square inches). A more conventional 4" bass driver will give you up to 80% more diaphragm area.
I don't get it.
The issue seems to be particularly relevant to small subwoofers. If you have a flatish 4" sub with a huge Xmax you've probably got 3" of cone (7 square inches). A more conventional 4" bass driver will give you up to 80% more diaphragm area.
I don't get it.
For concave cones, the resonance of the volume (of say, water, if you were to pour it into the cone) does play a minor role in midwoofer/tweeter design, but still less than baffle step, for example.
For subwoofers, the resonance is so far out of the operational range that it's completely negligible.
Shallower angles on the face of the cone tend to allow for an increase in tension loading of the diaphragm, which is useful to combat bending modes which decrease the durability and lifetime of a subwoofer much more than higher frequency drivers.
For subwoofers, the resonance is so far out of the operational range that it's completely negligible.
Shallower angles on the face of the cone tend to allow for an increase in tension loading of the diaphragm, which is useful to combat bending modes which decrease the durability and lifetime of a subwoofer much more than higher frequency drivers.
If you have a deeper cone you need a deeper basket to maintain a long throw. Flatter cone gives you more room to move. Think about it mechanically.
This isn't exactly true. Some woofers have no dust caps at all.
BTW Investigate those notched dust caps Dynaudio employs on they're woofers. They contribute to making more bass. They are partly why small 6" driver Dynaudio stand mounts are so good at reproducing full range bass so well.
My first response is, they aren't flatter unless the designer wanted it that way as a compromise. A deeper cone is stiffer and acts in a more pistonic manner which is important when they travel like they do.
The circular area is what is important, the depth has no real influence on the radiating surface.
The circular area is what is important, the depth has no real influence on the radiating surface.
Yeah- this has nothing to do with the other.
Besides the notches maybe breaking up the wave at the cap's edge, the main function of them is the minute wires that are located through them to align the voice coil during the assembly process. The wires are then removed after glue up and sealed with adhesive.
The notches have nothing to do with the bass response.
Besides the notches maybe breaking up the wave at the cap's edge, the main function of them is the minute wires that are located through them to align the voice coil during the assembly process. The wires are then removed after glue up and sealed with adhesive.
The notches have nothing to do with the bass response.
+1 Saved me some typing. 😉 Now if I could just find Danley standing on his Contrabass? subwoofer diaphragm pic to prove it was stiff enough not to flex at 7? Hz to insure accurate 14? Hz respsonse at high power.
I mentioned the notches for descriptive purposes only as most people recognize them.Not because the notches aid with bass in any way. I'm not claiming they perform any magic here people.
There design contributes to bass I can't remember why as it was a few years since I read about it. I'll see if I can't locate the original literature that explains how and why they add to bass weight but I'll find it and claim some redemption here.
Not really, they contribute added stiffness to the very thin diaphragms [ditto the 'tit' on some] to make more accurate bass with a flatter circular profile to fit in a shallower box, i.e. nothing new/inventive as the pioneers were using it by the late '20s if not before; RCA IIRC correctly and for sure by the late '40s when they also used them as the first passive radiators.
I've no doubt; like many things in life, rigidity is key to superior performance. 😉
Hmm, not sure what you're getting at; I mean it's pistonic pretty much all the way to the VC's diameter frequency and its long stroke length really only affects WLs considerably larger than the driver's effective diameter [d], so pistonic and as the WLs get to be < [d] it's barely moving in comparison, so stays ~ pistonic, though Altec measured [curvilinear] deep cone Altec Vs [ribbed] shallow cone JBL and there are some differences, but rather surprisingly not as great as one would think, i.e. their polars track very close above ~1.25 kHz, so large VCs/dust caps negate much of the differences between curvilinear and rib flex diaphragms, so at a bit of a loss as to why their 'tone' is obviously different to some of us.
I've seen nothing here to change my mind. GM seems to make one of the more valid contributions but that seems to be more about SPL direction.
do they really?
many subwoofers have large voice coils, so the dustcap gets bigger and thus the total diaphragm construction gets flatter. or dustcap and cone are merged to one continuous surface.
also subwoofer cones do not have to be light, so they can be made stiffer by thickness and do not have to rely on cone geometry for stiffness.
consider the surface of cone AND the motion direction.
your consideration would only be effective if all surfaces of the driver would move perpendicular to surface. but they do not.
it's about how much air is being moved.
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Hmm, in retrospect I guess I should have paid more attention to the OP's Q than just responding to later associated posts........
Correct, effective diaphragm area [Sd] * Xmax [or any longer up to Xmech if willing to accept its increasing distortion with increasing stroke and/or gamble on 'letting its smoke out' 🙁] = total swept volume [Vt] dictates how much acoustic pressure is generated, which is its peak SPL combined with the speaker's base efficiency in 'x' space loading, i.e. in this case [Sd] alone has no meaning if not moving.