Why You Do That?

[Hintzyboy 5,000+ posts]

That was written to cover RFs ***, just like companies underrate their products to cover their ***. RMS spec is a decent method to use when matching components if you'e underexperienced. But if you've done your research and know what you're doing, most woofers can be run safely over rms spec.

 

[creyc 10+ year member]

How does that change anything I said? I know this is true and I also understand why this is true.
Excess heat due to overpowering, whether clipped or unclipped, will damage a sub. Did I really need to spell that out?

Yes, I see that you understand this, but by far and away most people don't realize, much less understand why an amp pumps out more power when it clips.

It's actually an alternative way to set your gains, there will be a point where turning up the gain any higher will result in an un-proportional increase in output, the amp is clipping.

At the end of the day, all a speaker sees is power. Be it from a clipped signal, or a clean one at a higher output, average power over time is what heats the voice coil. I was merely trying to define it in terms so that those who aren't experts at amplifier topology could understand.

 

[Demi 10+ year member]

Yes, I see that you understand this, but by far and away most people don't realize, much less understand why an amp pumps out more power when it clips.

I am, far and away, most people. Please explain. The one thing everyone says is set your gains right to avoid damage and clipping. Alrighty then, what about this...Say sub A has an RMS of 500W, but could handle 1000W daily, while sub B also has an RMS of 500W but could be damaged by more than 750W. Assuming that both would be run off of AMP X which has an out put of 1000 RMS @ 2omhs, we use the gain setting formula: 1000(w) x 2 (omhs) and then take the square root of that, which will give you 44.721 volts. This is what confuses me most, by that math the settings on the amp would be the same for both subs, yet one cant handle nearly as much. Could someone clear this up for me?

 

[bballrrt06 10+ year member]

set your gains so that it's 750 x 2

soo...

38.73v

 

[Demi 10+ year member]

set your gains so that it's 750 x 2soo...

38.73v

Ohhhhhhhhhhhh, gotcha.

 

[BOOKER 10+ year member]

...Say sub A has an RMS of 500W, but could handle 1000W daily, while sub B also has an RMS of 500W but could be damaged by more than 750W.

This is the real point of this whole thread. You don't know how much more power you can run past the rms rating of the sub, because as stated before some can take it and some can't, so why take the risk.//content.invisioncic.com/y282845/emoticons/uhoh.gif.c07307dd22ee7e63e22fc8e9c614d1fd.gif

There is a thread of someone asking if he can run 1000 watt //content.invisioncic.com/y282845/emoticons/eek.gif.771b7a90cf45cabdc554ff1121c21c4a.gif to a 10" Arsenal, and some said that's overkill:furious: . That is my point.//content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

But I understand the overpowering statement. So if I run my pair of 12w3v2-d4 which I'm powering off a 750w bridged amp at 4 ohm, and I changed the amp to say for example a Crossfire vr1000d and wired them at 1 ohm that will give them like 1000w, they will sound a lot better?

Another issue is, when is the rated Xmax value measured, I understand it is at the rms rating, is that correct?//content.invisioncic.com/y282845/emoticons/rolleyes.gif.c1fef805e9d1464d377451cd5bc18bfb.gif

Good info.

 

[Immacomputer 10+ year member]

This is the real point of this whole thread. You don't know how much more power you can run past the rms rating of the sub, because as stated before some can take it and some can't, so why take the risk.//content.invisioncic.com/y282845/emoticons/uhoh.gif.c07307dd22ee7e63e22fc8e9c614d1fd.gif
There is a thread of someone asking if he can run 1000 watt //content.invisioncic.com/y282845/emoticons/eek.gif.771b7a90cf45cabdc554ff1121c21c4a.gif to a 10" Assassin, and some said that's overkill:furious: . That is my point.//content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

But I understand the overpowering statement. So if I run my pair of 12w3v2-d4 which I'm powering off a 750w bridged amp at 4 ohm, and I changed the amp to say for example a Crossfire vr1000d and wired them at 1 ohm that will give them like 1000w, they will sound a lot better?

Another issue is, when is the rated Xmax value measured, I understand it is at the rms rating, is that correct?//content.invisioncic.com/y282845/emoticons/rolleyes.gif.c1fef805e9d1464d377451cd5bc18bfb.gif

Good info.

Xmax has nothing to do with the rated RMS value. Also, that thread was talking about sending 1000rms to an Aresenal, not an Assassin.

 

[Demi 10+ year member]

Xmax has nothing to do with the rated RMS value. Also, that thread was talking about sending 1000rms to an Aresenal, not an Assassin.

But doesnt more power = more excursion? A more powerful electromagnetic charge has a larger area of effect does it not? //content.invisioncic.com/y282845/emoticons/ponder.gif.ec2527b23f1d287b60dcbba54f95edba.gif

 

[BOOKER 10+ year member]

Xmax has nothing to do with the rated RMS value. Also, that thread was talking about sending 1000rms to an Aresenal, not an Assassin.

//content.invisioncic.com/y282845/emoticons/slap.gif.87520e8ca8e90076ac30e777c0de5331.gif oops my fault, you are sure it is an Arsenal.

Ok, Xmax has nothing to do with RMS, then what?//content.invisioncic.com/y282845/emoticons/mad.gif.c18f003ab0ef8a0d9c27ca78d77a6392.gif

 

[T3mpest 10+ year member]

Xmax is simply how far the cone can move while keeping the BL (restoring strength of the motor) within 70% of it's resting value. Once a sub has moved out so far the the motor can no longer keep it moving linearly, it begins to distort more. How much power it takes to reach xmax depends on both the size of the enclosure it's in and the frequency it's playing. For lower frequencies hitting xmax is important, since you need alot of displacement to make those notes, let alone at a high volume. With higher sub frequencies hitting xmax can be nearly impossible. For a ported enclosure xmax is impossible to hit at certain frequencies, it may take 10000x the power that the sub is capable of handling to get there! However since the box is essentially making the noise near tuning, it doesnt' really matter. However, manufacturers to take xmax and rms into account when they design their subs. that's part of what make a recommended enclosure size. You can usually get xmax at certain frequencies out of your sub in it's recommended sealed box on RMS power, usually. If the box was much bigger than recommended you'd get xmax easier, but RMS could potentially damage the sub, due to it moving too far. Too small and you get little chance of hitting xmax before the thermal limits of the sub are reached. Finding the nice in between point is the tricky part, which is usually what the reccommended enclosure size is designed to show you!

 

[luvinthebass 5,000+ posts]

Xmax is simply how far the cone can move while keeping the BL (restoring strength of the motor) within 70% of it's resting value. Once a sub has moved out so far the the motor can no longer keep it moving linearly, it begins to distort more. How much power it takes to reach xmax depends on both the size of the enclosure it's in and the frequency it's playing. For lower frequencies hitting xmax is important, since you need alot of displacement to make those notes, let alone at a high volume. With higher sub frequencies hitting xmax can be nearly impossible. For a ported enclosure xmax is impossible to hit at certain frequencies, it may take 10000x the power that the sub is capable of handling to get there! However since the box is essentially making the noise near tuning, it doesnt' really matter. However, manufacturers to take xmax and rms into account when they design their subs. that's part of what make a recommended enclosure size. You can usually get xmax at certain frequencies out of your sub in it's recommended sealed box on RMS power, usually. If the box was much bigger than recommended you'd get xmax easier, but RMS could potentially damage the sub, due to it moving too far. Too small and you get little chance of hitting xmax before the thermal limits of the sub are reached. Finding the nice in between point is the tricky part, which is usually what the reccommended enclosure size is designed to show you!

great info right there!

 

[Immacomputer 10+ year member]

But doesnt more power = more excursion? A more powerful electromagnetic charge has a larger area of effect does it not? //content.invisioncic.com/y282845/emoticons/ponder.gif.ec2527b23f1d287b60dcbba54f95edba.gif

That's correct, but what I was saying is that the methods for finding xmax do not involve power at all.

RMS values are determined a number of ways by different companies. Some companies use pure thermal failure while others use mechanical failure. In either of these situations, xmax is not used. Xsus would be a different story though and all it does is limit the max potential RMS value while free-air if it is reached before thermal limits.

 

[JimJ 5,000+ posts]

But doesnt more power = more excursion?

Make the box large enough, you can send a driver to full Xmech with a fraction of the rated "RMS" power.

Part of why the environment is critical to understanding the woofer's limits //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif