Where to start?

It's a bit confusing, but the amp should be able to produce as much or more power than the subwoofer requires. Let's say that a certain subwoofer / box combination can handle 250 watts thermally and mechanically full bandwidth. You could pair the subwoofer with an amp that produces up to 500 watts, if care was exercised in it's operation, or an amplifier with 125 watts or less. The amplifier gain control could be set so that the 500 watt amp will never exceed more than a few watts, and the 150 watt amp gain could be set so that it is clipping continuously at half volume or less on the head unit.

Doubling the amount of electrical power (wattage) produces a 3 db change in output, for the change to be meaningful to a human, you need 10 db or 10x the electrical power, this is perceived as twice as loud. Contrary to popular belief, a subwoofer driver isn't a fuse, and it won't release the magic smoke if you exceed it's power rating for short peaks. It's the long term average power that will damage it if it is too high. Over excursion though isn't great for it and continual bottoming can damage the voice coil former or tear a spider, depending on what is the limiting factor.
 
PainSoFamiliar said:
As I'm doing research I see that the amps and subs are at certain ohms. I used to be a headphone guy so I know the higher the ohm the more power it needs. Does this mean a 4ohm amp will not sufficiently power a 8ohm sub?
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Don't think in terms of power... you need to think in terms of voltage. Voltage is the electrical 'pressure' that allows work to be done.

What's a watt, or what the heck does it all mean?? Well a watt is described as 1 volt into a 1 ohm load, resulting in a current of 1 ampere.

If I had an amplifier that was capable of driving a load between 1 - 16 ohms while not reaching it's voltage or current limits or burning up, with an output voltage of say 40 volts to the speaker terminals, I would have:

A 100 watt amp driving a 16 ohm load
A 200 watt amp driving an 8 ohm load
A 400 watt amp driving a 4 ohm load
A 800 watt amp driving a 2 ohm load
A 1600 watt amp driving a 1 ohm load.
 
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i see. definitely learned a good amount from you guys. thanks a lot! hopefully i can get a sub going in the trunk once my taxes come back
 
Impedance of a speaker is the DC resistance component along with an inductive component and a reactive component added together, and it's a complex relationship that changes with frequency, voice coil temperature, voltage and current flow through the coil as well. [ English ] a speaker is never really 4 ohms, or 2 ohms etc..... it's all over the map.
 
If I remember correctly the measured impedance of a sub is pretty much the least resistance it will give. A sub that's 4 ohms at 20hz may be 16 ohms at 80hz. I believe that's called impedance rise. Now on the amp side ill use my amp as reference. The lowest ohm load it can support is 1 ohm. When wired to a 1 ohm sub it will put out 600 watts continuous (rms). When wired to a 2 ohm load it will put out 450 watts. 4 ohms will give you probably around 200 watts. If I feed it a half ohm, it will put out around 1200 watts rms.... For a second, then it will shut itself down to prevent a thermal meltdown
 
Pretty much correct.... now as the voice coil heats up it's DC resistance ( DCR component ) of the impedance will rise, in some higher power applications as much as 30% of it's static room temperature DC resistance.

The degree of thermal rise is related to a bunch of different factors such as the amount of coil volume in the gap, the conductor material, the insulation material, the voice coil former material, whether there is nomex under the coil on the former, the types of adhesives used, the clearance from the gap to the coil ( both on the inside and outside ) and how much mass and surface area there is in the magnetic system. Also, as the power levels rise, the amount of heating is more or less proportional.

Having a well designed motor with copper or aluminum sleeves / copper or aluminum shorting rings will also reduce the amount of heat generated, by reducing the inductance.

I know I am probably way over the head of most people here reading, especially the OP... he must feel like trying to take a sip from a fire hose. :omg: My bad... for getting way off topic.
 
Depends on the sub. If your sub can only handle 200 watts rms then it would have to be a 4 ohm sub, under 4 ohms you will over power the sub. The best option for my amp would be a sub that can handle 600 watts rms and can be wired to 1 ohm. If you take a 600 watt rms sub and wire to my amp with a higher impedance than 1 ohm you will be under powering then sub. Which won't hurt anything it just won't be as loud
 
PainSoFamiliar said:
Do you think 200 is too small of a budget? I'm just looking for a simple sub to increase bass can maybe stretch to 250 but I'm a kid with limits! haha
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You can replace the door and rear deck speakers with something quality and get quite a bit of bass with an amplifier, no sub needed, IMO. Unless you want people outside of the car to hear everything. I had some nice Cerwin Vegas in a 91 accord that put out as much bass as a friends dual 10" setup unless he cranked it so loud it caused distortion.
 
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