Does power effect box volume?

[bkolfo4]

Impedance rise effects the amount of power the driver sees. Efficiency is referring to the output difference with the same power applied.

[Souldrop]

We are talking about 2 different aspects of overall efficiency at the moment, straight mechanical efficiency and box rise. The efficiency I was referring to was straight mechanical efficiency, the amount of cone movement with a given power not taking into account any impedance rise. That's why skittlesrgood seemed to contradict himself. He was talking about two entirely different concepts...The linear excursion should increase in a larger box all things the same because the air in the box exerts less pressure ie less "springingess" or resistance to cone movement. In a larger box you have to be careful because with increased cone movement with less power it becomes easier to cause over excursion the larger your enclosure becomes. If I'm mistaken in any aspect please someone correct me....And from what I've gathered box rise is just impedance rise inherent to the box's construction and its interaction with sub's electrical characteristics and tbh I don't know anything about box rise unless it is related to an induced emf and related to the amount of linear movement of the driver; then I can guess a little.

[Souldrop]

And mrskippy makes a good point, you can't magically increase a sub's power handling by a large amount just by making the box smaller. You still have the limit of thermal power handling; you can just sort of tweak a sub's mechanical power handling and efficiency at the cost of one or the other with varying enclosure volumes.

[DubNDodge]

Thanks a lot. This summed up all my questions, back to designing the box now lol.. more questions about that though in my other thread

[skittlesRgood]

and if I am not mistaken, box size does NOT effect thermal power handling.

my first thought was "no" but actually it could affect thermal power handling. in a smaller box the speaker moves less vs a larger box on the same power. the only thing that cools a sub is its movement. so if the sub moves less, it cools less. makes sense, right?

[skittlesRgood]

The smaller the box the greater the rise in most cases

in my testing I've seen the opposite.

The air in the box serves almost like a "spring." The larger your box the lower the "springiness" of the box. The "springiness" of your box helps to control the mechanical movement of your driver. So you have a coupled relationship between your box's efficiency and its ability to help control the movement of your driver. In short if you're putting more power to a sub you want to to make the box smaller to give your sub more mechanical control in that situation at the cost of a lower efficiency. A larger box does not necessarily give your sub more thermal power handling.

Let me grasp what was said. Efficiency means impedance rise or not? If so a smaller box will have a greater impedance rise while a larger box won't. So when it's all said and done. A 1k setup in a large box could be louder than a 3k in a small box. The large box will have a smaller rise than the smaller box. If this is the case, I might rethink getting the HDC3 and just stick with 1k on sdc2.5s

the answer is in what you have been told already. a big box will have less pressure inside of it, allowing the sub to travel easier (more efficiently). while a small box creates more pressure and is less efficient. there is always a happy median between the two that takes some time, or luck, to find.

put them in 2 cubes each. 12"s in general do quite well with that airspace. its a safe size if you only want to build once.

These two statements contradict each other don't they? I thought impedance rise meant the subwoofer was becoming less efficient. Because with rise, isn't it drawing less impedance from the amplifier? Or do I have it backwards?

no, those two underlined statements are completely different entities. you dont "draw impedance". impedance is the electrical resistance presented to the amp and it dictates the wattage produced from the amp.

[MrSkippyJ]

and if I am not mistaken, box size does NOT effect thermal power handling.

my first thought was "no" but actually it could affect thermal power handling. in a smaller box the speaker moves less vs a larger box on the same power. the only thing that cools a sub is its movement. so if the sub moves less, it cools less. makes sense, right?

Yup, it does. I still think it won't be significant. But I do agree with you that that change in movement can effect cooling.

[ALPINE408]

and if I am not mistaken, box size does NOT effect thermal power handling.

my first thought was "no" but actually it could affect thermal power handling. in a smaller box the speaker moves less vs a larger box on the same power. the only thing that cools a sub is its movement. so if the sub moves less, it cools less. makes sense, right?

Yup, it does. I still think it won't be significant. But I do agree with you that that change in movement can effect cooling.

it can be very significant i had a tiny box for 2 18's on 4k would not move much would heat up fast and start to smell double the power to 8k they would now move a good amount and would cool themslefs and not smell for long periods of time it all depends on the install like everything

[SlamminBeats]

if you're adding power, build it the first time for given power to be added.

[bkolfo4]

You can play notes at tuning in a big box and have the same issue with reduced cone movement. . .