I have just tried a dual "car sub " box on my Bryston
4BST that was given to me by a friend ...
he wasn't able to drive it with any amp at all..
well to be able to drive only 1 sub ( 4ohm ) i had to bridge my 4B to mono output wich gives 800W@8ohm
( ~ 1500W @ 4ohm supposdly )
and i was only barely able to drive it at all with all my sources and all at maximum power ...
now i wonder, why would someone want a subwoofer that is so hard to move?
ain't the point of a loudpseaker to actually move?
i can punch right in the sub without it moving much
( i can't even push it to bottom out )
the suspension is rubber that is probably 1/4" thick
and is hard to even move at all with my finger's nail
please explain ..
4BST that was given to me by a friend ...
he wasn't able to drive it with any amp at all..
well to be able to drive only 1 sub ( 4ohm ) i had to bridge my 4B to mono output wich gives 800W@8ohm
( ~ 1500W @ 4ohm supposdly )
and i was only barely able to drive it at all with all my sources and all at maximum power ...
now i wonder, why would someone want a subwoofer that is so hard to move?
ain't the point of a loudpseaker to actually move?
i can punch right in the sub without it moving much
( i can't even push it to bottom out )
the suspension is rubber that is probably 1/4" thick
and is hard to even move at all with my finger's nail
please explain ..
It's so kids can send 5000 watts to their subs at 20hz without the thing bottoming out. Efficiency means nothing when your 18 years old and just want to make noise.
The spider is there to control the cone at low frequencies. At higher frequencies the motor actually controls the cone.
I had a 10" sub in a car once that the spider came detached from. When I played frequencies above 50-60hz the sub played fine; if I went any lower the cone would lose control and start flapping around and bottoming out.
I say sell the thing to some kid looking to make noise and buy yourself something more useful.
The spider is there to control the cone at low frequencies. At higher frequencies the motor actually controls the cone.
I had a 10" sub in a car once that the spider came detached from. When I played frequencies above 50-60hz the sub played fine; if I went any lower the cone would lose control and start flapping around and bottoming out.
I say sell the thing to some kid looking to make noise and buy yourself something more useful.
i never thought about using it at all for myself 
was just playing with it, and astonished to see that something that stiff can actually give out some sound
I still don't understand the goal of having to push 2000000000 trillion watts in a subwoofer to make some noise ... there must be something more
i don't think that any amplifier that goes up to 2000W+
@ 4ohm can do it with anything less than 1-2%HD
Isn't the goal to try and match the air impedance as much as posisble like when using horns??
that thing is just like 100000000000 times the mass/stiffness of the air to move ..
need more explanation ..still don't get it at all!
was just playing with it, and astonished to see that something that stiff can actually give out some sound
I still don't understand the goal of having to push 2000000000 trillion watts in a subwoofer to make some noise ... there must be something more
i don't think that any amplifier that goes up to 2000W+
@ 4ohm can do it with anything less than 1-2%HD
Isn't the goal to try and match the air impedance as much as posisble like when using horns??
that thing is just like 100000000000 times the mass/stiffness of the air to move ..
need more explanation ..still don't get it at all!
im no expert on this but obviously this sub isnt gonna hit those lows without hella watts. But it probably hits those low to high mids pretty "stiff". I bet a couple of those subs and a couple more efficient subs would really fill in the tightness and the low end. For like metal, or hardcore metal, or even drum and bass.
I can see where they could be of use. But not worth the hassle maybe.
I dont know but i think for the most part efficient subs sometimes are almost to efficient for the high and low mids. I listen to metal and rock mostly so if you think of a kick drum i like to hear and feel the slap, and the thud, along with the low end of it in the room.
I can see where they could be of use. But not worth the hassle maybe.
I dont know but i think for the most part efficient subs sometimes are almost to efficient for the high and low mids. I listen to metal and rock mostly so if you think of a kick drum i like to hear and feel the slap, and the thud, along with the low end of it in the room.
nothing written on em ..
i was told by the guy they are from " SWAN" or whatever brand ...i believe that he doesn't even know..
they sure are hell heavy ...probably 150lbs for this 3/4" case and 2 12"
how can it play tight ?
i don't see how a plastic plate ( cause this is what it is ) can play any sound good ..
i was told by the guy they are from " SWAN" or whatever brand ...i believe that he doesn't even know..
they sure are hell heavy ...probably 150lbs for this 3/4" case and 2 12"
how can it play tight ?
i don't see how a plastic plate ( cause this is what it is ) can play any sound good ..
Don't forget the acoustic environment this thing is supposed to work with is radically different to most room / acoustic issues. It is about achieving high power handling in a cabin, maybe 3cu.m^3, and little else. The cone suspension is designed to be 1)hysteretic and 2) robust, because , with 'cabin gain', it doesnt actually have to be efficient - only to withstand the onslaughts of the nasty amps it will be tested with.
Just my 2c.
Just my 2c.
Hi JinMTVT,
There is a trend to design subs as stiff pistons rather than rely on T/S parameters. The ones I saw could easily support a man's weight without damage. Although the suspension was also stiffer, what you are describing is off the map.
It appears that these were designed to absorb power rather than deliver "music".
-Chris
There is a trend to design subs as stiff pistons rather than rely on T/S parameters. The ones I saw could easily support a man's weight without damage. Although the suspension was also stiffer, what you are describing is off the map.
It appears that these were designed to absorb power rather than deliver "music".
-Chris
Alot of the "thick rubber surround "car subs are really stiff when they're new. Thet need to "break in" for awhile before they loosen up. If it's an SPL sub it will have a FS in the mid 30's and be built to get loud at one frequency. What may be adding to the stiffness is the subs being in too small a box. It would be intersting to find out what brand they are and see what the T/S parameters are.
Perhaps these were actually part of a large lot of transducers specifically designed to turn ocean tidal energy into electric power and got shipped by accident to a car stereo shop? That could account for the 1/4 inch thick rubber surround.
or...
Maybe this is the device the man stands on when he is about to be launched out of a circus cannon. Again, a shipping error.
or...
Maybe this is the device the man stands on when he is about to be launched out of a circus cannon. Again, a shipping error.
ahhaha you guys are funny
Seriously, i am pumping an estimate of 1500W in 1 of those stupid driver, and i can even get past 60-70db of output for anything under 60-70hz
that has to be ridiculously low efficiency here
Still didn't get 1 reason why those things should exist at all....
i'll try and get some time to remove one of the driver out of the shitty box later on just to see what it is supposed to be
Seriously, i am pumping an estimate of 1500W in 1 of those stupid driver, and i can even get past 60-70db of output for anything under 60-70hz
that has to be ridiculously low efficiency here
Still didn't get 1 reason why those things should exist at all....
i'll try and get some time to remove one of the driver out of the shitty box later on just to see what it is supposed to be
Hi JinMTVT,
This driver will absorb all this power and give low sound output, although it may have great "snap". All that juice and no one stays awake.
It is entirely possible that it's a messed up recone or experiment. Could be rejects from off shore manufacturing. Does it really matter, they will be hard to sell unless you make it clear there are no refunds.
-Chris
Simple. It's a parent's dream (more the neighbours maybe).
This driver will absorb all this power and give low sound output, although it may have great "snap".
All that juice and no one stays awake.It is entirely possible that it's a messed up recone or experiment. Could be rejects from off shore manufacturing. Does it really matter, they will be hard to sell unless you make it clear there are no refunds.
-Chris
120V into 8 ohms = 15 amps = 1.8 kilowatts
120V into 4 ohms = 30 amps = 3.6 kilowatts.
A 15 amp, 60 volt transformer would me more appropriate. Perhaps a large welder wound up to maximum?
Very dangerous! I was joking.
I doubt you'll have a 15 amp outlet, let alone a 15 amp isolation transformer. Look at the size of the wires in a 15 amp mains extension cord - is the voice coil that big? what about the wires from the terminals to the voice coil?
think of the element in an electric oven, now shrink that element into something the size of the voice coil with the same heat output.
The sub would take about 2 seconds to catch fire, then you have 120V on the chassis. Death!
Similar care should be taken with the outputs on your big amplifier. Music can kill with enough power.
Perhaps the rubber surround was more compliant but it was treated with some inappropriate polish.
Edit: with a 100% efficient amplifier (impossible) 1 kilowatt requires 72 amps at 13.8 volts. In the real world we're talking at least 120 Amps per kilowatt of amplifier.
120V into 4 ohms = 30 amps = 3.6 kilowatts.
A 15 amp, 60 volt transformer would me more appropriate. Perhaps a large welder wound up to maximum?
Very dangerous! I was joking.
I doubt you'll have a 15 amp outlet, let alone a 15 amp isolation transformer. Look at the size of the wires in a 15 amp mains extension cord - is the voice coil that big? what about the wires from the terminals to the voice coil?
think of the element in an electric oven, now shrink that element into something the size of the voice coil with the same heat output.
The sub would take about 2 seconds to catch fire, then you have 120V on the chassis. Death!
Similar care should be taken with the outputs on your big amplifier. Music can kill with enough power.
Perhaps the rubber surround was more compliant but it was treated with some inappropriate polish.
Edit: with a 100% efficient amplifier (impossible) 1 kilowatt requires 72 amps at 13.8 volts. In the real world we're talking at least 120 Amps per kilowatt of amplifier.
Originally posted by theAnonymous1
Volfenhagen
12" Dual Voice Coil Car Sub Model: ZX-4712
Manufacturer's Specs (Based on 1 Voice Coil):
Fs = 30 Hz
Vas = 56L
Qes = 0.614
Qts = 0.526
TS measured with LMS (Free Air & Delta Mass-120g)
(Based on 1 Voice Coil)
Fs = 44.3 Hz
Vas = 31.4L
Qes = 3.79
Qts = 2.56
Absolutely ridiculous. Never encountered anything so stiff before. Judging from the thick rubber surround, seriously doubt it can be broken in. Tried emailing but unable to get through
Faxing them on Monday regarding discrepancy.
car woofers are used by kids that havent got a clue what they are doing or how things work. 9 time out of 10 they are mounted to a board and the back fires into the trunk. The only cabinet they see is the cabin and the trunk.
In these days of 5000+++ watt class D car subwoofer amps traditional woofers dont last long. Kids are into max volume, and who cares about distortion. half the time they crank it up well well WELL into distortion anyway. These ar enot audiophiles here guys.
Car stereo compititions are well into the 170+ db range. i think the record is over 180 actually.
Even most 1000 watt rated pro audio subwoofers wont handle anywhere near 1000 watts down around 20-30hz. maybe a couple of hundred at best.
SO, a super stiff suspension makes sense when there is no back box and it will be seeing 5,000watts plus clipping. and they will.
In these days of 5000+++ watt class D car subwoofer amps traditional woofers dont last long. Kids are into max volume, and who cares about distortion. half the time they crank it up well well WELL into distortion anyway. These ar enot audiophiles here guys.
Car stereo compititions are well into the 170+ db range. i think the record is over 180 actually.
Even most 1000 watt rated pro audio subwoofers wont handle anywhere near 1000 watts down around 20-30hz. maybe a couple of hundred at best.
SO, a super stiff suspension makes sense when there is no back box and it will be seeing 5,000watts plus clipping. and they will.
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