car amp with default speakers?

**Blackrazor** · 03-16-2005, 06:12 AM

The power dissipated in the coil will be similar regardless... What may change is the coil movement, as stated. What the BCAE site talks about is what happens when the coil doesnt move as far for EXTENDED periods of time... most speakers are designed to use the motion of the cone for some form of cooling, so even tho as stated above in the short term there wont be any major difference, if you distort your speakers heavily for a good period of time, say 10 minutes or more, then heat will build up due to the lack of cone-motion-provided cooling.

I didnt make an issue of that because in my mind, its not hard to tell when you're speakers are distorting, let alone distorting heavily... and anyone who would sit there and listen to speakers heavily distorting for 10 minutes plus has more issues than how long their speakers would last

You have to have VERY specific circumstances to cause a speaker to fail with less than its power rating. On the other hand, its a simple matter to blow a speaker with too much power. So in my mind, having too much power is a greater risk

In the end, it all comes down to common sense. It doesnt matter whether you use a 5w amp or a 500w amp, so long as you ease off once you hear the speakers distorting, either via an amp signal or of their own accord

Who wants to listen to distortion anyway

**Blackrazor** · 03-16-2005, 06:23 AM

As another opinion, heres a direct quote from the Car Audio Australia FAQ

Note that clipping per se is not dangerous for the speaker. It is the actual power of the signal that causes the overpowering. For example, an amplifier may produce only 100WRMS of power, beyond which it will clip. If clipped, the signal may reach around 200WRMS. However, if the subwoofer it drives has a power handling rating of 300WRMS, it will not be overpowered or at risk of overheating. Therefore, the subwoofer will happily reproduce a clipped signal of 200WRMS all day long; it will just sound terrible and the amplifier may overheat!

So understand that clipping is a sign that the amp is being pushed beyond its limits; that the onset of clipping causes a rapid increase in power output, albeit highly distorted; clipping does not necessarily mean the speaker or subwoofer will be overpowered.

In agreement with the stated above, it is my firm beleif that it is not the 'type' of signal that you need to fear but the overall power level itself. Feed 100w of power, be it clipped or not, into a 100w speaker and for short periods you should be fine. Feed 200w of either clipped or clean power into a 100w speaker, and you'll soon run into trouble

**Nic** · 03-16-2005, 07:31 AM

Originally Posted by Blackrazor

You have to have VERY specific circumstances to cause a speaker to fail with less than its power rating. On the other hand, its a simple matter to blow a speaker with too much power. So in my mind, having too much power is a greater risk

In the end, it all comes down to common sense. It doesnt matter whether you use a 5w amp or a 500w amp, so long as you ease off once you hear the speakers distorting, either via an amp signal or of their own accord

Who wants to listen to distortion anyway

This is different from saying distortion dosent kill speakers, what i would say is more accuratly correct is that distortion is less likely to damage speakers than many people would have you believe.

my sub is rated at 300w and my amp is rated at 300w, if it was distorting the amp would be putting out over 300w and my sub would be able to cope with less than 300w, with this combination, if pumped up for too long, the speaker could fail.

and on another note, there are lots and lots of people who lack common sense

**RedGTiVR6** · 03-16-2005, 08:14 AM

thanks for taking the time to explain your side of the issue. I appreciate it. I do understand where you are coming from, and I agree with it, just as I always have.

Now, I'm trying to figure out how to say this without coming across....unexperienced and unintelligent....but it's 7 in the morning and it was a late night last night and I'm not thinking straight yet...

here's my question then

why, over about 10 years of installing, would you have a customer come in, want a set of speakers installed powered off of an aftermarket deck. Say the speakers need 80 watts of continuous power, and the deck only puts out (at most) 20 watts rms. Why would there be a larger percentage of these installs returned with locked up speakers than those who have the exact same set-up, only with a small amplifier that pushes out adequate power to those speakers?

in general, the systems that had adequate power came back far fewer times than those that were under powered....

not sure how you explain that away??

I just have a hard time believing that distortion has absolutely no effect on the life of a speaker.

why is it that, and just hear me out here, those vehicles (and you probably know which one's I'm talking about) that ride around booming some terrible, awful, distorted rap, need their speakers replaced more often than others? can't tell you how many of those would come in, want boom, and have no money.

they get a 200 watt amp, insist on a power hungry sub, and blow it a few days later....not the case with those that put an adequate amount of power to the sub...

**ekip** · 03-16-2005, 10:23 AM

Originally Posted by Nic

my sub is rated at 300w and my amp is rated at 300w, if it was distorting the amp would be putting out over 300w and my sub would be able to cope with less than 300w, with this combination, if pumped up for too long, the speaker could fail.

There is some differents how the power of amplifiers is counted. Most of them tell PMPO power what is point max vs point min. its about 150W or so... Then when you read the specs there is 75WRMS at 1KHz and 0.1% Thet is continues power with 0.1% of distortion. And if the amplifier is realy good one that distordion number is like 0.005% - 0.05%.

**Blackrazor** · 03-16-2005, 04:17 PM

Originally Posted by Red GTi VR6

in general, the systems that had adequate power came back far fewer times than those that were under powered....

not sure how you explain that away??

I'm in the business too, as you may be aware. I've never ever, in all my time, seen a speaker that blew up from not enough power or through being fed distortion. I've seen plenty that were driven too hard for the installation, or were trying to play frequencies they werent equipped to play. You feed a solid 20w from a headunit into a '100w' speaker that is trying to play 30Hz on a Little Jon song, and your poor '100w' speaker that only has about 2mm of excursion is suddenly trying to get to 4mm excursion and its *** is slapping on the backplate. So sure, its distorting, and sure its killing it, but its not because of the amp signal being distorted, its because the speaker is trying to play what its not designed to play, and is damaging itself in the process.

Put the same 20w (or 60w, or whatever) from an amp, highpassed with no low bass coming through, and all of a sudden the speaker isnt playing 30Hz, its not over excurting, and all it has to worry about is its thermal handling. So voila, its fine.

But the thing to remember is that its NOT that fault of the amp playing distortion. Its the fault of people being cheap and not buying the gear needed to play the music they want without distorting the speaker. I mean, all it would take to fix it is a couple of $5 capacitors on the speaker leads acting as a high pass filter at around 80Hz, and they could drive their speakers off the headunit all day every day no worries at all

Originally Posted by Red GTi VR6

why is it that, and just hear me out here, those vehicles (and you probably know which one's I'm talking about) that ride around booming some terrible, awful, distorted rap, need their speakers replaced more often than others? can't tell you how many of those would come in, want boom, and have no money.

Again, as you know, power handling is a thermal limitation, the mechanical limits depend on the sub design and the installation. In all my time, i've never seen a high powered sub with decent excursion killed by a low powered amp. Ever. Not once. I've seen subs with high power ratings that really couldnt handle jack all power when it came down to it ruined by too much power. But never a good sub driven within its limits failing.

If you want to test it out, go get a high handling high excursion sub like a DD 3512 or something, feed it 200w and clip it as hard as you like, and leave it running. Come back 3 hours later, and see if its any worse the wear. It wont be, i know because i've done exactly that experiment

The problem with the beleif that amp distortion ruins speakers is it encourages people to buy massive amps for their speakers, which is fine but also makes it even EASIER for them to nuke their speakers if used improperly. The problem is not the amp distorting. The problem is the numbrat in the drivers seat trying to drive his system past what its capable of. If you do that, then distortion or no distortion, something will eventually blow

**Blackrazor** · 03-16-2005, 04:19 PM

Originally Posted by ekip

Most of them tell PMPO power what is point max vs point min. its about 150W or so...

Some of the PMPO figures you see, you wonder if the method they use to calculate it is measure the distance to the nearest phone box in inches, and multiply it by the advertising budget

**RedGTiVR6** · 03-16-2005, 04:25 PM

What you are saying makes complete sense....that it's actually that one would be asking too much of a speaker, more than it is designed for, and that that would in turn cause the speaker to blow, not the install, not the low power, etc...

I guess I just have a hard time believing that distortion would have ABSOLUTELY nothing to do with launching a speaker....

call me hard headed, but I just don't see it...

**poseur** · 03-17-2005, 02:48 AM

Recorded distortion is just plain silly to speak of, and it would appear as though your'e simply using it to prove your point. When will that ever be a factor? In any place where this conversation has come up, it's a matter of misadjusted gains, the distortion that results is clipping, or dc output. Ever put dc output to a speaker? what do you get? it puts the speaker at one end of it's mechanical capability, then add in a bit of AC from the music that IS playing, and you've got speaker crunch.... whoca res about the heat, how about the coil bouncing off of the backplate. A speaker only has somuch Xmech, and that can easily be overcome by DC signal.