40 watts over that big of a deal?

nyydmb12

I just installed a new amp to run my front polks and after a few minutes of playing with the cross over and wondering why they sound different I find I forgot to switch the HPF on. When I bought this amp I had to decide whether I wanted a 60 watt 2ch for the backs or a 100 watt 2ch for the fronts, and bridge my 4ch to a 100 watts. So I went with a 110 watt amp to power the fronts. I'm not to worried about giving to many watts to the front with a 10 watt difference, but the 40 watt over difference I'll see on the rating for the rears startles me. Right now its running 40 watts and you may say a 20 watt increase to 60 isn't a lot, but its a 50% increase. Well I suppose I could always bring it to a local car audio shop.

TouchOfEvil

Your fine, it's better to ahve too much power than not enough. Just adjust the gains on the amp to suit the speakers.

MacLeod

You do need to worry about having too much power as overpowering a speaker is the ONLY thing that will kill it aside from shoving a screwdriver thru it. You either push the suspension beyond its mechanical limits or you build up more heat in the voice coil than it can dissipate and either of these 2 things can only be done with overpowering.

That being said - a 100 watt amp isnt making 100 watts all the time. Your can can do 100 mph, but I doubt it does it all the time. Music is dynamic and unless youre listening to big bass heavy music with the volume maxed out, chances are youre not making anywhere near the upper limits of power the amp is capable of. If you were listening to MUSIC at a MUSICAL level then youll probably never have a problem.

bigaudiofanatic

Agreed if you are going to be blaring it louder than you can stand it still would not be 100 watts.

audiobliss

MacLeod wrote: »

You do need to worry about having too much power as overpowering a speaker is the ONLY thing that will kill it aside from shoving a screwdriver thru it.

That's slightly misleading, I think. Sure, sending too much power to a speaker is the only thing that will kill it. I'll buy that. However, that's NOT to be taken as 'using an amplifier rated at too many watts is the only thing that will kill it.' To quite the contrary, TouchOfEvil alluded to, an amplifier rated at too FEW watts will kill a speaker very easily and more inadvertently than a higher quality, more powerful amplifier.

If you're using an amplifier that puts out less than what your speakers are rated at, it's likely you'll have the gains up on the amp and the volume up on your HU, which will very quickly lead to your amplifier sending your speakers a distorted signal. The distortion itself could cause your speaker to get hot and kick the bucket, OR the fact that you're totally overpowering your speaker because I clipped signal is MUCH more powerful than a clean signal. Your underpowered speakers are now being overwhelmed.

I don't know if that made any sense at all, but I wanted to try and clarify. Too much power kills speakers. But it's generally easier to send too much power to a speaker with a weak amplifier (by pushing it too far and sending a distorted signal) than by using a more powerful amplifier that's set right.

exalted512

audiobliss wrote: »

That's slightly misleading, I think. Sure, sending too much power to a speaker is the only thing that will kill it. I'll buy that. However, that's NOT to be taken as 'using an amplifier rated at too many watts is the only thing that will kill it.' To quite the contrary, TouchOfEvil alluded to, an amplifier rated at too FEW watts will kill a speaker very easily and more inadvertently than a higher quality, more powerful amplifier.

If you're using an amplifier that puts out less than what your speakers are rated at, it's likely you'll have the gains up on the amp and the volume up on your HU, which will very quickly lead to your amplifier sending your speakers a distorted signal. The distortion itself could cause your speaker to get hot and kick the bucket, OR the fact that you're totally overpowering your speaker because I clipped signal is MUCH more powerful than a clean signal. Your underpowered speakers are now being overwhelmed.

I don't know if that made any sense at all, but I wanted to try and clarify. Too much power kills speakers. But it's generally easier to send too much power to a speaker with a weak amplifier (by pushing it too far and sending a distorted signal) than by using a more powerful amplifier that's set right.

So basically what you're saying is, overpowering a speaker is the only way to kill it?

It doesn't matter if you have a small amplifier or not, as long as the gains are set appropriately, you will not have a problem.

Distortion does NOT kill speakers. Overpowering them does. I can run the dirtiest signal ever to my mids and not ever blow one, as long as the signal is still not overpowering the speaker.
-Cody

MacLeod

audiobliss wrote: »

That's slightly misleading, I think. Sure, sending too much power to a speaker is the only thing that will kill it. I'll buy that. However, that's NOT to be taken as 'using an amplifier rated at too many watts is the only thing that will kill it.'

Feel free to point out where I said that.

To quite the contrary, TouchOfEvil alluded to, an amplifier rated at too FEW watts will kill a speaker very easily and more inadvertently than a higher quality, more powerful amplifier.

Nope. Depending on the size of the amp of course but its a lot easier to fry a speaker with a bigger amp. Hook up a 50 watt amp to a 100 watt speaker and sure, its more likely youll push the amp into clipping but there is still a very good chance you wont do it especially if you use common sense. A clipping amp kills speaekers by sending out a one time big blast of power that will snap the speaekrs suspension. Now hook up a 200 watt amp to that speaker. All that nice clean power can lure you into a false sense of security and youre more likely to have the volume up pretty stout and build up too much heat in your voice coil and there goes your speaker.

If you're using an amplifier that puts out less than what your speakers are rated at, it's likely you'll have the gains up on the amp and the volume up on your HU, which will very quickly lead to your amplifier sending your speakers a distorted signal. The distortion itself could cause your speaker to get hot and kick the bucket, OR the fact that you're totally overpowering your speaker because I clipped signal is MUCH more powerful than a clean signal. Your underpowered speakers are now being overwhelmed.

Thats wrong on so many levels. First off as long as the signal is below the speakers thermal handling limits, it can be 50% distortion and itll play it all day long. A speaker doesnt know nor care how clean the signal is its reproducing - so long as its within its limits. Second, a signal is a signal. 500 watts of pure distortion is no different than a 500 watts of clean signal. The sound may be different but the power wont be.

I don't know if that made any sense at all, but I wanted to try and clarify. Too much power kills speakers. But it's generally easier to send too much power to a speaker with a weak amplifier (by pushing it too far and sending a distorted signal) than by using a more powerful amplifier that's set right.

Thats wrong too. Again, it all depends on the size of the amp. A lot of SQ guys I know love to use hundreds and hundreds of watts per driver - Im talking 300-500 watts per driver.....and they blow speakers all the time with a signal as clean and pure as the wind driven snow. Now I ran for 2 years with 50 watts and never blew anything. A small amp will run out of clean power before it starts to clip and youll hear this crappy sound and likely wont push the amp any harder. Also, when an amp clips its a spike of power which will bottom out the speaker. Most of the time this wont instantly kill the speaker but youll still hear it and usually realize youre giving it too much and back off.

Now with a big **** amp, its a lot harder to tell when youre putting too much power to the speakers unless theyre bottoming out and if youre playing a track that doesnt have a lot of bass in it, then you could completely melt the voice coil without ever causing it to bottom out. Im not saying a clipping amp isnt dangerous to speakers, it can kill in an instant, however a clipping amp can and usually does give off some warning signals before it kills where a monster amp likely wont because its more of a "slow burn" rather than a single big blast.

Bottom line - overpowering is the only way to kill a speaker. Clipping an amp will do it and using too much clean power will do it.

So whats the best way to go? Get an amp that best matches your speakers power handling ratings. Extra power is fine so long as you use common sense with the volume and gain.

TouchOfEvil

MacLeod wrote: »

So whats the best way to go? Get an amp that best matches your speakers power handling ratings. Extra power is fine so long as you use common sense with the volume and gain.

I'm pretty sure my first post offered up the advice to adjust the gains to match the speakers. But i guess you didn't read that part.

Also yeah too much power can blow of speaker but if you adjust things to work with your setup then you have clean power and a amp that is setup to power everything properly.
A amp underpowered and running a speaker that can clip at times is more dangerous if you ask me as alot of people try to push small amps too hard.
If it's got enough power and not running hard you won't risk this and as long as you set the gains properly you won't over heat the coils.
In the end what you are trying to say is no differant from what i'm saying.
Your side under power but adjust and don't clip.
My side adjust to not over power and all is well.

MacLeod

TouchOfEvil wrote: »

I'm pretty sure my first post offered up the advice to adjust the gains to match the speakers. But i guess you didn't read that part.

Yeah I read that part and its wrong. The gain doesnt adjust the power of the amp - it adjusts the input of the amp to the output of the head unit and unless youre using a head unit with .5 volt pre-outs you can still get a big amp up to full power pretty easy even with the gains on the floor.

A amp underpowered and running a speaker that can clip at times is more dangerous if you ask me as alot of people try to push small amps too hard.
If it's got enough power and not running hard you won't risk this and as long as you set the gains properly you won't over heat the coils.

Go back and read my last post.

Your side under power but adjust and don't clip.

Nope. My side is that its ok to use a smaller amp and its ok to use a bigger amp. The key is to understand what youre doing. If youre going to use a smaller amp, then pay attention to how hard youre pushing it. Dont crank the gains up to 3/4 to compensate for low power and if you hear the speakers bottom out or hear a lot of distortion in the signal, back off. If youre going to use a bigger amp then dont crank the volume up to full tilt assuming that because youre not hearing the speakers bottom out or any distortion that youre not hurting anything. And that since there are a lot fewer warning signs with a big power amp thats its easier to kill a speaker with an amp that is way too big than with one that is way too small.

TouchOfEvil

I don't know maybe you never turned everything down a amp before then adjusted it with your volume levels to your desired full volume point...?
Because if you did then you would realize a amp turned all the way down and i'm talking mroe than just gain the output increases by alot.
Also you telling me not to be stupid when playing with a small amp is no differant than me saying don't be stupid with a large one.
But to each his own.

MacLeod

TouchOfEvil wrote: »

I don't know maybe you never turned everything down a amp before then adjusted it with your volume levels to your desired full volume point...?
Because if you did then you would realize a amp turned all the way down and i'm talking mroe than just gain the output increases by alot.
Also you telling me not to be stupid when playing with a small amp is no differant than me saying don't be stupid with a large one.
But to each his own.

Wow. Reading your posts hurts my eyes. Your post makes no sense at all.

Im not sure how turning the amp down increases the output and Im not sure what other than the gain you can use to adjust the amps output. And Im actually saying to not be stupid with BOTH small AND large amps. Are you even reading my posts?

TouchOfEvil

I'm out i feel like i'm talking to a brick wall.

MacLeod

Funny, I was just thinking the same thing.

audiobliss

Awesome thread. Glad I could be a part of it.

frosty2k

MacLeod wrote: »

they blow speakers all the time with a signal as clean and pure as the wind driven snow.

hehe that made my day

only126db

Sending a clipped signal to a speaker will most definately kill the speaker, there is no ifs ands or buts about it....

Continually sending a clipped signal to speakers will cause them to heat up and die.

Driving speakers with an underpowered amp trying to make up for lack of volume by adjusting the gain too high will cause clipping.

MacLeod

only126db wrote: »

Sending a clipped signal to a speaker will most definately kill the speaker, there is no ifs ands or buts about it....

Continually sending a clipped signal to speakers will cause them to heat up and die.

Yeah, there actually are a couple ifs, ands and buts about it. If the clipped signal is below the thermal handling limits of the speaker, you can run a clipped amp all day long. Hook up a set of 150 watt speakers to a typical head unit and turn the volume full blast. At full clip its doubtful a HU will put out more than 30-40 watts and that amount of heat can easily be dissipated by the speakers with no problem nor will it be enough to push the suspension beyond its limits.

dudeinaroom

you can kill a 150 watt speaker with 30-40 clipped watts. 40 watts of clipped signal will produce more heat in a voice coil than a non-clipped signal. The non-clipped signal has a peak, and then drops off, the way speakers were designed to work. A clipped signal will come up to that peak, and hold it until the signal has come back below the the amps clipping level, the way a speaker is not meant to function. This longer duration of a clipped ,almost "dc" like signal, keeps the current in the voice coil longer not letting it cool right away.

To the people who say too much power doesn't kill speakers, go hook the good old pos and neg to a car battery terminal. To those who say too little power won't hurt it either, hook a couple D batterys in series to your speakers and leave them that way for a while.

Guess your damned if you and if you don't

later,
dude

eloplayspolo

this would be so easy if someone just made a sticky with everything cody and Mac has ever said about this topic... it would prob be a 200 page post with the amount of times ive seen this argued.

Jstas

Yay!

A thread full of angry posts that I'm not in!

Keep posting angry, I'm having fun reading!

dirthog

With a clipped signal you're increasing the average power sent to the speaker. I like the "dc" example.

Is it enough to kill the speaker well that's a test I don't like to perform.

Jstas

dirthog wrote: »

With a clipped signal you're increasing the average power sent to the speaker. I like the "dc" example.

Is it enough to kill the speaker well that's a test I don't like to perform.

Distortion does not necessarily come from a clipped signal. Also a clipped signal is more likely to burn out an amplifier or line source than a speaker. Provided you aren't trying to push the amplifier to its max at the time. Then again, most people who are clipping signals are driving a signal source too hard to get more production out of a system with low limits.

Don't confuse a clipped signal with clipping amplifier power either.

MacLeod

dudeinaroom wrote: »

you can kill a 150 watt speaker with 30-40 clipped watts. 40 watts of clipped signal will produce more heat in a voice coil than a non-clipped signal. The non-clipped signal has a peak, and then drops off, the way speakers were designed to work. A clipped signal will come up to that peak, and hold it until the signal has come back below the the amps clipping level, the way a speaker is not meant to function. This longer duration of a clipped ,almost "dc" like signal, keeps the current in the voice coil longer not letting it cool right away.

To the people who say too much power doesn't kill speakers, go hook the good old pos and neg to a car battery terminal. To those who say too little power won't hurt it either, hook a couple D batterys in series to your speakers and leave them that way for a while.

Guess your damned if you and if you don't

later,
dude

Thats kind of an extreme example. I mean, yeah I could hook up a car battery to a speaker and it would probably fry it after 15 minutes. I could also shoot one with a .50 caliber sniper rifle. Im pretty sure that would do one in as well.

Your scenario would only be relevant if a person generally listened to test tones at full tilt boogie for several minutes. Who and why would you do that?

Music is dynamic and 40 watts of clipped MUSIC will never hurt a speaker that can handle 150 watts.

A speaker doesnt care what kind of signal its getting. It doesnt care if its clean, dirty, distorted, maladjusted, nonconformist, perverted or whatever - all it cares about is if its within its thermal handling limits. 50 watts of pure distortion wont hurt a 150 watt speaker but 200 watts of pure sonic goodness will melt the voice coil.

eloplayspolo

MacLeod wrote: »

full tilt boogie

things like this are what make MacLeod my fave.


....that doesn't make me sound strait at all

dirthog

Jstas wrote: »

Distortion does not necessarily come from a clipped signal. Also a clipped signal is more likely to burn out an amplifier or line source than a speaker. Provided you aren't trying to push the amplifier to its max at the time. Then again, most people who are clipping signals are driving a signal source too hard to get more production out of a system with low limits.

Don't confuse a clipped signal with clipping amplifier power either.

I wasn't confused, I was talking about clipped amplifier power. Isn't that what started this thread. 40 watts over with a new amplifier.

eloplayspolo

what started this thread was someone saying "its better to have too much power".... when too much power is what kills your speaker.

The reason u buy an amp with headroom is so that u dont have to push it hard.... u want it to work with ease. u dont buy it so u can have "too much power".

Jstas

dirthog wrote: »

I wasn't confused, I was talking about clipped amplifier power. Isn't that what started this thread. 40 watts over with a new amplifier.

No, you stated this:

dirthog wrote: »

With a clipped signal

Signals on RCA connections can clip also.

I am not a mind reader and if you state something that is viable and applicable but not accurate then how am I supposed to know you meant something different?

An amplifier clipping is different than a signal source clipping. Both are possible, both have differing results.




As far as buying an amp with headroom, you don't necessarily buy an amp with too much power. You need to look at specs. Things like slew rate, dampening factor, dynamic power ratings vs continuous power ratings, input sensitivities and what voltage all those ratings are measured at are all important is showing you what kind of headroom is already built in to the amp. Most amplifiers will have have head room already built in but the specs will tell you how much is there.

If you have a speaker that handles 150 watts of power, pushing it with a 200 watt per channel amplifier is not the best thing to do. Finding an amp that pushes the speaker with 130 watts of power but with favorable specifications for headroom will work out much better.

Overpowering a speaker kills it because it pushes it past its physical and thermal limits. Under powering a speaker will not kill it unless you are overdriving your amplifiers trying to get more performance out of your setup than is there. That is what causes amplifier clipping. If anyone tells you that under-powering a speaker will kill it without mentioning why, ask them why. If they tell you any other reason than what I just said, you can call shenanigans.



Just for example, I have been under powering a dB124 by 120 watts for 4 years now and before that I underpowered a dB104 for almost 11 years and had no problems. I am also under powering speakers at home with an 8W x 2 tube amplifier on speakers that are rated for about 70 watts. Still no problems and they have been going strong for 6 years now in that state. I'm also overpowering a set of bookshelf speakers on my computer but due to the near field listening I do with them, I rarely push them anywhere near where they might be compromised.

dirthog

You are correct I did say signal, but in my mind I knew what I was talking about. My bad!

I wouldn't look at slew rate or dampening factor when purchasing an amplifier. These rates have no audible effect.

Purchase a decent amp with the power ratings you want and you'll be happy.

Jstas

dirthog wrote: »

I wouldn't look at slew rate or dampening factor when purchasing an amplifier. These rates have no audible effect.

Just because they do not have an audible effect doesn't mean they aren't important. Honestly though, the kind of do have an audible effect.

From Wikipedia:

In electronics, the slew rate represents the maximum rate of change of a signal at any point in a circuit. Limitations in slew rate capability can give rise to non linear effects in electronic amplifiers.

http://en.wikipedia.org/wiki/Slew_rate

From Wikipedia again:

In loudspeaker systems, the value of the damping factor between a particular loudspeaker and amplifier, describes the ability of the amplifier to control undesirable movement of the speaker cone near the resonant frequency of the speaker system. It is usually used in the context of low frequency driver behavior, and especially so in the case of electro-dynamic drivers which use a magnetic motor to generate the forces which move the diaphragm.

A high damping factor indicates that an amplifier will have greater control over the movement of the speaker cone, particularly in the bass region near the resonant frequency of the driver's mechanical resonance.

http://en.wikipedia.org/wiki/Damping_factor

Pretty important stuff that has direct correlation as to whether you blow your junk up or not.

dirthog

While they have big important definitions at wikipedia does not mean it will have a huge effect on quality of sound or whether it blows your junk.

Here's a recent post on another forum.

Quoted by Andy Global Product Line Manager, JBL Car Audio Harman Consumer



Neither matter much. Slew rate is basically a measure of distortion at high frequencies--how fast can the amp swing from - to +. It's taken into account for any power measurement over the useable band of frequencies at some distortion level. damping factor is nearly useless. It's an erroneous indication of how muh control an amplifier's output impedance (or lack of imedance) has over the speed at which the woofer returns to rest after a signal stops. The formula fails to take into account the primary EMF generator in the speaker and its relationship to the speaker's DCR. Basically, the speaker controls its damping and the amp doesn't.

Basically, don't sweat either of these specs.


He said it better than me.

If they don't have an audible effect then they don't matter. These two specs are NOT going to blow your junk. The person using the equipment incorrectly will.

Jstas

Those two specs have a direct correlation on how your amplifier makes power and how it sends that power to your speakers. They can offer insight in to how much "headroom" your amplifier has.

They are relevant and they do affect sound. Just because you got one guy who is a product line manager telling you different doesn't mean that the laws of physics don't apply.