e_lectro

Using a small amp when you want a large one? Yes. Fault of the amp? No. You will not get 1000W of sound out of a 100W amp. You will get quieter sound, not a blowen speaker, that is all.

This is about the clearest description I can give you on this:
from:http://www.carsound.com/UBB/ultimate...=019131#000000

Bass Mechanic

no im saying that first and formost as a blanket statement running a smaller amp will not have a negitive effect on the sub other than running it with less power than its rated for. i dont care if it's a clipped signal or not it may sound like crap but the speaker isnt going to suffer any more ill effects than if its clean.
running a larger amp rated at or above the wattage of the sub can and probly will damage the coil from heat.

as for adjusting gains i would say that people who firstly buy a wallmart amp and crank the gains and also buy wallamert subs are far more likely to blow shit up then people who have the money and some common sence to buy the right equipment and know how to use it correctly. or at least get it installed by smeone who knows how to.

i think from my experience common sence and ones income and spending potential go hand in hand. if your generrally stupid person you probly dont have the capacity to earn a whole lot of money.

disclaimer, if you dont have money right now its not because your stupid. sometimes people have tough times in life.

Bass Mechanic

im Dieing to hear eludoos responce to this. lol

elduderino

I was not trying to blame amps, and I was not trying to say that speakers fail due to being driven at low wattages. I have never said that speakers blow up with low levels of undistorted power, so if you're arguing that point, it's kinda off-topic. Look, I don't care if it IS Richard Clark, he's talking about an amp that is NOT clipping and I am talking about an amp that IS clipping.

As far as the fault of the amp, e_lectro, I have never been trying to blame the amp - I've simply referred to what is easier. As in more likely - happens more often in real life.

This is kind of a circular point - if stuff is installed so you can't blow it up, then you can't blow it up. We all agree about that.

That doesn't mean that it's not easy (or easier) to install it where you CAN blow it up. Of course it is!

Is it easier to drive a speaker with a clipped signal using a small amp than a big amp? Is it more likely to happen? Yes or no?

Yes, it is easier - regardless of what you want to blame it on - gain setting, etc., the base question is, is it easier, and the answer is, yes, it is. Doesn't have anything to do with the shape of the distortion curve or the quality of the amp - smaller amps by definition go into clipping with fewer watts of output than larger amps, and people are more likely to have smaller amps, just judging by the sales figures! I don't mean TINY amps, I just mean lower than the speaker power rating.

And this discussion is still discounting HU deck power and OE amps that have no gain adjustment, but are preset at the factory. Placing lower-efficiency speakers in such a system with higher insertion-loss crossovers means that the user is going to ask for higher volume settings to reach an acceptable volume level, and with that amp, he is more likely to go into clipping, since it's small. Blowing a speaker is thus more likely to result, even though the smaller amp is below the power rating of the speaker used.

The intent here was to warn people that they should not expect installations to be problem free just because they bought speakers with higher ratings than their amps have. This is a common question/complaint/issue on the sales floor, on forums, and with DIY shadetree installers, and the EIA/CEA was trying to come up with a way to commmunicate this to consumers back in the early 90's - and simply saying "it's not the amp's fault" was not considered an effective way of communicating it to the end user. The industry was trying to decide how to deal with this problem back then, and I don't think they've figured it out as an industry, because the biggest complainers as suppliers were the worst offenders when it came to using speaker wattage ratings as a marketing tool.

Bass Mechanic

Eludo this is what you typed this is what started this discussion. you made an incorrect statement. stop trying to twist the facts of what you said all around. stay on topic and lets move on shall we?
you had no proof to back this statement up and we have proven that.

Bass Mechanic

again dont contridict yourself.
and when you asked me to explan how a 15WPC head unit blows up a 200 watt speaker
you were referring to exactly the same scenerio were you not?

elduderino

\

What I said stands. It's a pretty good description of a clipping amp. If you don't like the analogy, make a new one, but it's a good description of a clipping amp.

Bass Mechanic

Plllltttt!
whatever i might as well be talking to a hairdryer for the amount of good its going to do.

ClutchPerformer

jaydub

Mega

Here are some questions that the answers will help me form my opinion on the subject:

1. Can an amp send more than its rated peak power when it is clipping (I already know it can exceed its RMS rating)?
2. Does the output level continue to increase as distortion/clipping increases, or does clipping already infer max output has been attained?
3. Can you make any amp clip?
4. Is a low build quality amp more likely to clip than a high build quality amp?
5. Can an amp send direct current when it is clipping?
6. Is it likely direct current will damage a speaker?

I’m starting to see that both sides of this argument have valid points. Making some assumptions, here are four scenarios (assumptions are:amp is adjusted in a way that max volume produces clipping, and amp can deliver twice it’s rating when clipping... I know that’s a generalization, but go with me for the example):

50watt amp and 200watt speaker:
In this case the 50watt amp peaks at 100watts and therefore no matter how bad it’s clipping, it can’t hurt the speaker. But, you would get low volume that would distort before desired volume. Sustained play could damage the amp, but not the speaker.

150watt amp, and 200watt speaker:
In this case, everything is great until clipping occurs where the amp could spike to 300 watts and damage the speaker. The chances of clipping are still likely due to desired volume level, so this is a dangerous setup.

200watt amp and 200watt speaker:
This case is similar to the above only a higher volume can be attained before clipping occurs, so under normal conditions, this is safer. Arguably this may be the safest setup even though the amp could still be driven to clip which could send 400watt spikes.

300watt amp and 200watt speaker:
In this case, the amp could blow the speaker when producing a clean signal. However, it would not be as likely to blow the speaker quickly since clean signal is not erratic like clipped signal. The clean signal would distort the speaker in a fairly controlled manor, so unless the user didn’t know or didn’t care distortion was occurring, it would be fine. However the user that would turn any of the systems up all the way will blow this one the quickest. But on the other hand, this system would be able to deliver the maximum undistorted safe signal. So for that reason, this may be considered the safest setup (depending on the user).

For me personally, I think #4 would be the best. I would never need to worry about clipping, and would be able to back off at the first sign of distortion while being able to maximize my speakers.

For a person not concerned with sound quality, I think #3 would be best. They have the lowest chance of blowing things if they tend to only go for desired volume regardless of quality.

Bass Mechanic

1. no because RMS is the DC equivelent in an AC circuit. thereofr if it were straight DC the wattage would be the same. and for the record you can only measure peak watts with a meter or O-scope because peak watts in an AC circuit are only calculated not measured in heat so the whole thing about getting more watts frm a clipped signal doesnt hold water except for the fact that the sub will generate additional heat due to the fact that its not following a smooth sine wave.
its literally being told to move to the forward position and hold it there then sweep back to the rearward position hold and repeat. this combined with the fact that the springiness of the suspention of the sub trying to move the cone back to center will also cause the coil to generate excess heat. the key here is the sub has to move to cool itself
here is a simple analagy if you had a coil sitting in free air and no magnet or movement involved it would generate the same heat or dissapate the same watts wether the signal was sine, square or triangular or any other type of signal even DC. the measure of watts is simple the voltage times the current = watts or in ohms law P=I*E the signal matters not. but to understand why it would get hotter under a clipped signal is simply because of the fact that if there were no movement of the coil at all that same 200 watt coil would probly smoke at 50 watts or less because it doesnt have the ability to dissapate heat unless its moving.
if you limit its movement with a clipped signal and the fact that the sub was not intended to stop on a dime and reverse direction much as a square wave would cause it to it will A. not be able to cool as well and also generate more heat then in normal operation. the watts havnt changed any it just lost its ability to stay cool when air is not passing over the windings to keep it cool.

2. yes any amp will clip wether it be the the signal to the preamp or the preamp to the power amp (internally) in other words you can get a clipped signal by running more input to the amp than the preamp can handel or turning the preamp up so high that it will take a clean signal and clip it at the input of the power amplification stage. how easy it clips depends on the gain value of the transistors of the amplification stage your asking about.
a clipped signal is notheing more than an over driven signal or one that causes the transistors of the amplifier to reach their full "ON" state in a push pull configuration amplifier 1 transistor turns on to send current to the sub in a forward fashion where the other compliment transistor turns it on in a reverse direction.
without trying complicate things assume an amp has voltage rails in the output stage of + 20 and - 20 volts with respect to reference 0 the speaker outputs will be able to send no more than 20 volts + or - to the sub no matter how large the signal is. if you exceed this limit the signal stops at 20 volts when if the voltage were higher it would have continued so you get a straight DC situation breifly while the input signal swings all the way positive and then starts back to 0 again and the same on the negitive side.
in other words you could also cause an amp to clip with the same input signal if you could adjust the power supply voltage to the output stage. thats why unregulated amps have a higher wattage rating at 14.4 volts then they do at 12 volts as is stated by many manufacturers (ex 150 watts at 12 volts 175watts at 14.4 volts.) with the lower voltage the amp would clip sooner with the same input signal. and as a result its wattage output stops right there at 150 instead of 175.

3. it's possible but you cant blanket statement that because it depends on the input sensitivity adjustment and the gain of the transistors themselves. but the answer is really relitive to the watts in this example.
if your asking me to compare 2 amps 1 at 25 watts and one at 250 watts if both have an adjustment sensitivity between 200 mv and 2 volts with a 2 volt signal applied they would both clip in theroy at the same setting provided the adjustment knob on both amps was actually that accurate.
if you hooked a 4 volt signal to both examples you would clip the amp on its lowest sensitivity (2 volts) at about 1/2 volume again assuming the controls were that accurate.

4. yes in a mannor of speaking it is DC but only as long as it takes for the signal to return below the limit of the voltage rails. assuming you played a 60 HZ signal severly clipped the duration you would be sending dc to the sub would only be for about 1/4 of a cycle in each direction of a 60 hz signal so about 25% of the time it would be getting DC and it would still change direction 60 times a second. i am too tired to figure out how long that is in seconds but ltes just say its very very brief and far less than a fraction of a second

5. direct current will definitly damage a speaker. as in if you put a battery to it it would only take a few seconds of straight DC to smoke the coil because there would be no movement of the coil to keep cool. of you applied 20 volts to a sub of straight DC on a 4 ohm load the watts would be 80 watts and no moving air to dissapate it. 80 watts is pretty damn hot imagine grabbing an 80 watt light bulb while its been on for a while to get the glass temperature up to the full 80 watts worth. yea without cooling that would definitly smoke a coil.

hope this helped clear things up

i dont think i numbered thoes right but i think you can get the jist of it.

e_lectro

SO..... all we need now is subs with built in fans to cool the voice coils when they are clipping... just wait, it will be all the rage next year! lol

elduderino

OK, in an attempt to get past personal disagreements and come up with text for C) that doesn't involve deciding whose is bigger, I submit the following:

(Note: The added text is in italics. I don't think these contradict each other, but they address problems that have been brought up and hopefully cause everyone to feel like Barney the big purple dinosaur).
This text replaces this:
*(not me!)

Bass Mechanic

dude, give it a rest! now you just not making any sence at all. you contridict yourself in every attempt you have made to save face.
lets move on shall we?
i already pointed out the facts. how about you just copy and past the facts of what has been spelled out for you and stick it in your sticky.

elduderino

Take your meds, you sad little man.

slo007

I'm under powering my sub as follows: 150 watts rms bridged from amp to a 300 watts rms sub (JL W3v2 12"). Am I in the clear?

Bass Mechanic

as long as your gains are adjusted correctly you have nothing to worry about.

slo007

Great, thanks.

jpswanberg

hi guys, interesting discussions. a couple of points only, of the many subs I and amps I have used, I have only blown two: one through massive long term abuse (a jl 8w1 in a microsub box, rated at 100w continuously) driven by a 300 w Rockford amp for over three years, the second because it was totally crap (rockwood? amp and some swapmeet $29 special sub). Typically I drive my subs (reputable brands) with a lot of power (reputable brands). No problems due to professional installation and reputable brands.

The other issue I am interested in hearing your opinion about is soundstaging and imaging. I am a nut when it comes to those two issues. At present I have a set of dynaudio seperates in the front doors, time aligned using my alpine head unit and no rear fill. I am interested in changing out the door speakers for a set of dynaudio 3 ways installed in the doors/kickpods and no time alignment. Has anyone done anything similar? Thanx, jps

elduderino

Where are your tweets?

jpswanberg

mounted co-ax style in the grill, although in my last car (02 GTI) they were mounted in the stock position, actively x-ed over and time aligned by themselves. jps

elduderino

There was a poster who PM'd me about building pods in the TSX with a 6MT... looks awfully hard to do in a 6MT daily driver to me. Hope he sees this...

I have not done that setup. That said...

I assume the dyne 3-way you are talking about is the dome tweet/dome mid setup. Since you have the latitude, I would make the following suggestions:

Consider buying the Dyne drivers seperately rather than the 3-way kit. This allows the following:

1) You could go with the bigger tweeter. In a pod a slightly larger tweeter is irrelevant, so consider the MD130 tweeter over the MD100, or even the Esotar if you have the cash.

2) The Dynaudio 3-way passive xover is not very flexible as I understand it. They cross the tweeter over at 4K and the mid/midbass xover is at 700. This range is not quite 3 octaves, and the passives are almost undoubtedly interfering with each other to some degree (passive crossovers work by increasing the impedance at and above/below a given freguency at an increasing rate.) I have made lots of 3-way passive xovers and I don't think they are the end of the world, but if you can, I would use a seperate set of amp channels for the midbass than for the mid/tweet, and use an electronic xover at 700 Hz or so.

This leaves the xover for the mid/tweeter (edited for error). Dyne crosses over that tweeter at 3K with a cone midbass, but at 4K with a dome midrange (the midrange can obviously play higher, and in a pod there will be little straight-line "beaming" at higher notes to worry about, since they are pointing at you). The best result would be to build custom passives for these at 4K, I suspect - Dyne lists no 2-way crossover at 4K.

Since Dyne's xovers are somewhat off-the-shelf anyway ( they use the same xovers regardless of which cone mid you are using, or whether you have the MD100 or MD130 tweeter - and we know they aren't identical) I think you might be best off by designing your own passives for the mid/tweet crossover. Time alignment between the two should be irrelevant, as the mid and tweet will be on the same plane. You may at some point go with time aligning the mid/hi output with the midbass door output, and that would work out OK with seperate midbass and mid/tweet channels.

The pod setup would allow easy tinkering with the passive component values if you stash them inside until you nail them down for good - good news for an imaging nut : )

jpswanberg

thanx, jps

tuan209

not sure which alpine HU you have, but if you got the 9835, why not just use the xovers on that instead of building some passives? active > passive. i believe most alpine headunits that have time alignment also have a 3/2 way xover. as for kicks, good luck. its going to cost you some money to make some kicks for the tsx as the hood release and fuse box is in the way.

elduderino

Hey, tuan, if it has a 3-way active xover, I was assuming he would need a 4-way total - tweet/dome mid/cone midbass/woof.

Unless you were proposing that he use an external xover with the subs? I think that that would be a fine way to do it if you didn't want to do time alignment (which you said you were willing to let go of).

If you wanted to do time alignment, I assumed that you would need to use it in 3-way mode and high-pass the pods...

I'm Batman

So how is it that a head unit stock or aftermarket can blow speakers if there is no gains to adjust and it isn't being over powered/under powered?

Do I hear distortion?

proaudio22

I would like to add my two cents into this. This subject is much debated in the pro audio world. I think Mega made a good list of questions, and I don’t exactly agree with Bass Mechanic.

1. Yes, square waves are approx. 2x as powerful as a respective sine wave of the same amplitude. The crests and troughs of the wave are now much shorter resulting in an almost constant time the amplitude is applied to the voice coil. Bass Mechanic is partially right; the measured power (well easily measured, like with a multimeter) would be pretty much the same. This measured power is the amplitude of the “wave”. However with a sine wave, the amplitude is held for ~25% of the time. Simple measurement alone is not valid here.
2. Clipping is referring to the amplitude rising and reaching the limit of the device. The wave will continue to rise and the crests/troughs (IE tops) of the wave will become chopped off. At the onset of clipping, the overall power difference isn’t that great. It does indeed rise as more and more of the wave is chopped off, up to the point it becomes a complete square wave.
3. Any amp with it’s limiters removed, can be fed a signal that in conjunction with it’s own internal gain, will surpass the maximum input of the amplifier and will clip the signal.
4. Yes and no. Taken off the shelf, a high quality amp generally can produce more raw power. However; gain, power output, etc equal; neither will clip sooner than the other.
5. Again, yes and no. Technically a straight square wave is stepped DC, it changes the direction of current in a regular pattern, that pattern is determined by the dominant frequency at the amps input stage(s). If you send the amp a straight 80Hz sine wave and run it into hard clipping, it will basically turn to DC and reverse polarity at a rate of 80 cycles per second. However, it’s rare to reach that situation in reality.
6. Again, yes and no. This is dependent on the current available to the speaker. In Bass Mechanic’s example of a car battery, it would more than likely damage the speaker. The car battery can supply much more current than the driver can safely handle. However, hooking a simple 9v battery to the speaker will cause no damage at all as it doesn’t have enough current. It will simply hold the voice coil out (or in) until the battery runs dead.

The examples below are extremely good examples!

YES! As long as the potential power output of the amp does not exceed the capabilities of the driver, it will not damage it, only sound like crap.

Good example of a basic under powering situation. However, as long as the amp nor anything else in the signal chain is allowed to clip, it will not damage the speaker. Volume will be lower than driver can produce.

This is the basic “safe” powering assumption. As long as the amp or anything else in the signal chain isn’t allowed to clip the signal, no damage will be done to the driver. The driver will reach it's RMS rating, but not it's true potential. However, there is really just as much danger, if not more, in this setup as the underpowered setup if it is allowed to clip.

This is safer, yet still not exactly what we should shoot for. The problem is there are too many “fluff” specifications given by manufacturers today. The only power rating of a driver we should be concerned with is the RMS rating. Good powering would be 2x the RMS rating of the speaker. This provides enough power so that peaks are not allowed to clip the amp (IE headroom). These peaks are easily handled by the driver if it’s clean power. This requires someone who knows what they are doing else it can do more damage than any of the other setups as it can hit the driver with 4x it’s rated power.

Mike_SilverTSX

You ARE the man! That was like one of the "hear's how electricity works" lectures from my Dad. Great stuff.

BallsOfSteel

Good Stuff !!!!

xX24Xx

My eyes hurt because of this forum!

BallsOfSteel

Shouldn't this be a sticky???

Jonesi

Nope....

goofy8

Beautiful, just simply beautifully stated.

proaudio22

Really if you ask a 40 watt amp to try to play 80 watts you'll get 80 watts of distortion. Lil bit worse than stated before.

badboy

great thread....keep it going guys..