I think I may get banned for this. What do you do?

[Looneybomber]

Putting drama aside. What do you do? Amp limit or driver limit?

Do you buy amps big enough to push your subs deep into the danger territory producing lots of distortion, or do you buy enough drivers (subs) so that when your amp is at full tilt, your drivers arn't being bottomed out?
Modified by Looneybomber at 2:55 AM 6/29/2007

[qsiguy]

Not sure what the title has to do with anything but to answer your question. There are many opinions on this subject but IMO...

If you have decent quality drivers you are more likely to damage them by electrical distortion than mechanical distortion. I rarely see blown subs from too much (clean) power. Almost always the customer bought too small an amp and the amp is clipping which damages the speakers quickly.

Also, if you have a properly designed enclosure it's pretty difficult to bottom out subs unless you have lots of power. If you have too little power you'll be pushing it harder to get the volume you want, too much power and you'll likely not be pushing it quite as hard because it'll sound good at a higher volume.

A trained ear should be able to hear either mechanical or electrical distortion and back off on it a bit. Trouble with most of my customers is they don't back off when they should, then I get to sell them more equipment because they can't ease up on the "throttle".

[Looneybomber]

Not sure what the title has to do with anything but to answer your question.

Oh, I thought I was going to get banned on the other forum.

I was actually debating with the owner and designer of a driver company on a product they were getting ready to release to the public. I driver limit my stuff so that I have endless amounts of clean power, where-as they were severly amp limiting their product. (1Kw vs. my idea of using 4Kw for added headroom)

After it was all said and done, if I was in their shoes, I would likely severly amp limit my product too to help protect the drivers since it would all be covered under warranty.

I was just curious what the mass majority of people actually do.
Modified by Looneybomber at 3:46 AM 7/4/2007

[Rex]

Have power to spare, and speakers to tear. That's the way it should be.

Distortion kills .

[PoorManQ45]

If you have decent quality drivers you are more likely to damage them by electrical distortion than mechanical distortion. I rarely see blown subs from too much (clean) power. Almost always the customer bought too small an amp and the amp is clipping which damages the speakers quickly.

Umm... No. It is impossible to blow a sub with just distortion.

Here is the test that Dan Wiggins from Adire Audio did.

He took a 200w amp and one of their 12" subs that handled 2000w RMS. He hard clipped the 200w amp. It sounded like total butt, but no harm at all was done to the driver.

No, take a 2kw RMS amp and a 2kw sub and then clip the amp. That is asking for trouble. The reason for this is that when an amp is clipped the sine wave becomes squared off. Meaning there are moments when the sub pushes out and holds, then goes in and holds. As you know alot of the cooling for the VC comes from the air movement generated by the cone movement. Less movement means less cooling.

Just a note, the power ratings on subs are usually termal ratings, not mechanical. The reason I say that is because almost any sub placed in a large port box can be made to bottom out before reaching the thermally rated power level.

Now, in a small sealed box you'll reach thermal limits before mechanical limits.

I personally would go with an amp that can put out more power then the subs can handle. This allows you to easily tune the gains so that you are just below the distortion point of the sub. With an amp that is too small you'll usually hit the clipping level of the amp before hitting the distortion point of the driver. This makes it a little harder to tune the system properly.

[qsiguy]

Umm... No. It is impossible to blow a sub with just distortion.

I have done and seen similar tests proving the opposite. That flat spot in the sine wave you are referring to is DC current to the speaker. Wire your speaker to your car battery and see how long it lasts. The only difference is that the DC current is only momentary when the amp is clipping. There are always exceptions to any rule. Your quoted test for instance. That driver was rated to handle 2000WRMS and can handle quite a lot of abuse, much more than any 200w amp can deliver.

This is a debate that's not worth any further discussion as it will likely be one of those debates that will last the test of time.

[PoorManQ45]

I think what you're referring to is this:

Lets say you have a sub that can handle a thermal max of 2000w RMS. This is including the cooling that would be caused by the cone moving back and forth.

Now, take a 1800w RMS amp and hard clip it. There will be those moments when the sub goes out and holds, and then in and holds. On these holds there is no cooling going on. So the VC heats up more then normal.

In this instance the sub will fail.

Again though, this isn't due to the distortion. This is due to the power exceeding the thermal limits of the sub.

Remember, you don't have to be clipping an amp to reproduce a square wave. You can input a square wave and have the amp reproduce it. So, this wouldn't be distortion(distortion being variation from input to output), but could still kill a speaker if there was enough power being reproduced

[qsiguy]

I see your point about inputting a square wave. The difference being that when the amp doesn't produce the square wave until it's at it's limits and the input square wave would be at a lower power level producing much less heat.

I think we are on the same page through different points of view and definitions of "distortion". It all boils down to heat damage or physically overdriving the speaker.

[PoorManQ45]

You got it buddy.

Heat and physical limitations are the only thing that'll damage the driver

[Looneybomber]

You got it buddy.

Heat and physical limitations are the only thing that'll damage the driver

You forgot one more.Dropping it at the UPS depot will also crack cast aluminum. How do I know? One of my SDX-15's is cracked. It's all good though, they sent me a replacement, so now I have three sitting in my room, waiting to send the broken one back.

[qsiguy]

Ouch, ya that'll do it too!