techno101

I have a question about my stereo system. I installed one pioneer 10" subwoofer rated at 300 W continous, and 800 W max power. I have a pioneer amp rated at 300 W max power output. I sounds great, but I cannot turn my bass all the way up. If I do my subwoofer quits making sound. It will hit hard then stop for a second or two and then hit another note. Then it stops agsin for a second. Is the woofer pulling all the juice from the amp during which the amp is building up power for the nextnote?

Gummie

If the amp stops putting out sound that means it's going into protect mode. If it's going into protect mode that means you're turning it up WAY too loud for the amp. It simply can't keep up, is clipping the signal, etc.

An amp will clip output when turned up too loud (the sine wave will turn into a square wave) meaning that the woofer will have extreme forces exerted on it instead of a smooth transition from one peak to the other. This is really bad for speakers. When an amp is pushed too far it will eventually go into protect mode. This is most likely what you’re experiencing.

Turn it down! This is extremely bad for your sub not to mention your amp. It sounds like you need a bigger amp to live up to your listening tastes.

Dracul

yeah you definently need a bigger amp. generally i like to have an amp that will give abuot 50watts rms more than what the sub rms is rated.

also giving a sub too little power will hurt is just as giving a sub too much power will..

Justin Horne

Uh... Really?
I'm not saying you're wrong at all, just that it doesn't make sense.. Since power can be equivalent to volume, wouldn't that mean low volume's hurt the sub?
For example. If an amp, at 75%, only puts out 40% of the subs rated rms, , and with a volume output of x, than I think you're saying that hurts the sub.. But if you play the sub with an amp fully capable of driving the sub, and play it at volume x, isn't that identical?

And if so, doesn't that mean we're all blowing all of our speakers nearly all the time?

Or I could be totally wrong too, and I can accept that.. I just don't get it.

Dracul

well i figure i'll back up my claim, since i do realize it does sound a bit weird.. but here is one explanation

this is from audiobahn's website
"Problems occur when distortion is fed to a speaker. This occurs more often when you are dealing with an underpowered system, typically the owner will turn up the volume too much or set the amplifier gains too high to try and get more volume from the system. This can greatly increase distortion of the signal. This will destroy any speaker. When a speaker is overpowered, however, it is not nearly as common to have these problems, so speakers aren't blown as much. It is certainly possible to destroy a speaker thermally by overpowering it or distorting the sub."

at crutchfield they also say its better to overpower than to underpower..

pretty much the main reason underpowering a sub or any speaker for that matter damages it is because the majority of us turn the volume up and distortion occurs.. and distortion kills speakers.

Justin Horne

Ok, now THAT I can believe...
By underpower, you/they are meaning, using an amp that, at most, can't drive the sub like the owner wants. Then, the owner maxs the sub, doing all that.. Totally believable.
I thought they/you were saying that simply not giving the sub it's full power would hurt it.

Like those NBC ads, The More You Know.

techno101

thanks for all your help guys, this really helped me out!

NEEDAZ

That's your problem. Distortion bad...

NEEDAZ

This is absolutely inaccurate, but I'm glad you added the clarification.
What you are talking about isn't under powering a sub, which will NOT do any damage to a speaker. What you are talking about is over driving the amp, which will clip the signal. This gives the speaker MORE average power and builds MORE heat in the voice coils (more power=more heat), not less power. Just being a stickler for semantics.

techno101

Distortion? Hmmm, but I don't hear anything unusual. Like, no scratchy-distortion from the speaker. It just hits hard and then clicks for a beat or two then hit and miss again. Sounds good though.

NEEDAZ

You may not be hearing the clipping, but I bet it's there...

sully91rs

Get a more powerful amp and then listen. It will sound better and have no hit and miss clicks.

techno101

Awesome!!.........I already have the amp picked out. Thanks for everyones help!

1meanGTA

what amp?

rx7speed

that's weird
when playing guitar I generally turn the gain up fairly loud to drive it into clipping and have yet to blow a speaker. this is through a few different means. some by signal shaping by using diodes and such like that which shouldn't really effect curent but with a few of the solid state and tube amps I have built I have also set it up where the distortion comes from the transistor or vacuume tube going into saturation and cut off. that point at saturation you get a nice amount of current going through there.

the only speakers I know of though that are touchy to distortion based through the amp itself are tweeters. they aren't able to handle much in current, and there motion range is generally fairly limited. but any of your larger speakers should be able to handle this distortion fairly easily.

1meanGTA

feel free to send YOUR equipment worth hundreds or thousands of dollars a clipped signal. i'll stick with my clean signal. maybe you aren't clear on this, but clipping and distortion are not the same thing. a clipped signal is when the amp is pushed too hard, and instead of sending a sine wave, like the sound waves you see on oscilloscopes in the old 30's frankenstein movies, the peaks go off the chart, and instead of straight up and down, they flatten at the top. imagine your speakers making sound off that electrical signal, then tell me its fine. speakers generally "blow" from the voice coil overheating and melting. hence the stuck cone on a lot of blown speakers. that type of signal creates a LOT more heat in the voice coil than a clean signal, which is why a speaker could handle a clean 1000 watts rms, but may blow off 500 clipped watts.

as far as sound quality goes, clipped vs unclipped, theres no comparison. i was just barely clipping my rl-ps when i had the nine.1 on them to get the output i wanted. switched to a more powerful amp which didnt have to break a sweat to run them, sounds a hundred times cleaner, especially when the bass goes low. most woofers can take a mildly clipped signal, but it still is hard on them, and wont be even close to as accurate.

rx7speed

I build electronics and I can tell you distortion and clipping can be the same.

distortion is a change of the signal as it goes through the output.
or in nutshell signal going in is not the same as the signal that goes out. be it from overdriving the amp or using wave shaping techniques.

clipping is a specific type of distortion that called as such cause the peaks of the waveform are chopped off. it case you might not know this you can cause clipping just by putting a diode in line with the signal. but it isn't going to blow your amp.

when those peaks get cut off that is distortion.
though distortion does take on many other forms then that.


but let me ask you do you think that all the distortion I am doing with my gutiar isn't caused by pushing the amp too far? that's some of the best sounding distortion out there even moer so when tube based. diode based clipping works but there are other methods also. still though with most designs I enjoy the overdrive method.

my speakers and amps are doing just fine care to explain that?
oh wait actually I did blow a tube once. shorted a wire and next thing I knew the heater fillament blew out. my stupidity but thankfully 12ax7 aren't that expensive least for use with this amp which was a cheapy practice one I had built

1meanGTA

clipping generally doesnt blow amps. i never said any clipping at all will blow your speakers, i admitted to having clipped my 12's for months. what i said was that unless you have a good ear for distortion and know when its being pushed too far, clipping the signal to your speakers is a good way to blow them. it doesnt matter quite so much with a guitar amp, as it doesnt have to play voices and everything with any degree of clarity. also i'm sure audiophile guitar players do not clip their amps while they play lol.

i agree on the tube amps, even though some of them have upwards of 8 percent distortion, they just have a warm crisp sound to them, partly caused by the distortion. but again, clipping and distortion are completely different.

rx7speed

clipping IS distortion
though distortion doesn't mean it's clipping

audiophile guitar players? you mean playing clean I'm taking it.
even those amps generally have distortion as the amplifier is part of the instrument and sound your trying to get. plug a guitar straight into a hi/fi amp and it generally doesn't sound as good. but clipping is common to use when playing guitar. ever hear country, blues, rock, metal, pop or anything else like that? your not listening to clean guitar playing or as you call it "audiophile" playing :-p on every song I'm sure . chances are they play into a little clipping or mild distortin of some sort.

as far as clipping I have run my guitar in just into just about into square wave clipping. part of the fun when running a .5-1v signal through 1 stage with around 10db of gain then two more stages of a max of 60db gain. it was going rail to rail real bad.

as far as the sounds it has to play. and what does having to play voices and clarity have to do with clipping/distortion and blowing speakers?

trust me though I've run my guitar amp through more clipping then you have ever put your speakers through and they are doing just peachy. and have been played from around 40hz I think it is with a bass guitar up to around the 12k hertz range.

so I think that more then covers the high end that a sub would play and just about goes as low as most subs. these speakers are still doing fine and have been doing this since the 80's since this is how old the amp is. still stock speakers.

1meanGTA

with a guitar amp, you may want a bit of distortion to get the sound you want. (by audiophile i meant guitar players who have a taste for clean, high quality sound)

however in a car speaker or subwoofer, which is what the topic of this thread is in regard to, clipping does nothing but cause unnecessary distortion, and put speakers at risk of being blown. its great you've clipped the hell out of your guitar amp since the 80s and its still going strong, but how many people do you hear about every day on audio forums or stupid people you know/work with who blew their car speakers? if you're listening to rock or anything with distorted guitars or whatever recorded, fine, you can reproduce the distorted sound with a clean signal. theres no reason to clip your amps to attempt to get a more distorted "better" sound, unless you simply dont know what clean high quality sound is.

when i was speaking of the voices and non-guitar sounds, i was saying that in a car, you have to play a wider range of frequencies than a guitar amp does. a guitar amp can be reasonably distorted, but you dont want that listening to music.

rx7speed

a sub (which was the type of speaker in question) doesn't not ahve the frequency range as my guitar amp.
if my guitar amp has been running this long without blowing spearers when being overdriven how is it going to blow your speaker?
whats the difference that makes your speaker so special?

most everyone I know of who has blown speakers (myself included have done so at levels taht where way to high end ended up pushing the speakers to far and broke the surrounds, or had the surrounds start falling off.

had one situation where a voice coil failed but that was do to something falling on the speaker.


but here is a question what is so different as far as the speaker is concerned between a signal that is clipped at the amp vs clipped as part of the recording?
either way the voltage goes up and has a sudden stop with all the harmonics that are generated

1meanGTA

this is pointless, im leaving this thread. do me a favor, clip the hell out of the speakers in your car. enjoy that muddy, crappy sounding music for a few days before you blow your speakers. im done.

http://forums.caraudio.com/vb/showthread.php?t=63933&highlight=clipping

good reading material. you may learn a few things.

rx7speed

calm down man

and I don't enjoy listening to distorted music. it sucks so I don't deny you should listen to distortion.


just trying to get at an actual explanation as to how clipping could be so bad and how the speaker would see clipping any different then a signal that is clipped to start with as ti is recied (ie heavy metal)

1meanGTA

i dont know, i dont build speakers. if i had to guess i would say most artists dont record any clipping on their albums, i know i wouldnt. clipping maybe classifiable as distortion in that the output is different from the input, but just because there is a lot of distortion does not mean the signal is clipped. when i played guitar way back in the day i had a distortion pedal, i dont know specifically what it did, but im guessing it didnt just clip the signal.

i can play stuff like korn or the deftones, that uses a lot of distortion in their guitars on my components, and it sounds extremely accurate, not at all like clipping.

rx7speed

your prolly right in that did more then just distort. there was prolly shaping of the sound in the tone stack. as well as maybe shaping of the clipping itself be it sharp clipping or more of a softer rounded clipping. who knows

but most distortion pedals use basic clippingto get that sound.

if you get bored one day take a look for information on distortion pedals, schematics, and oscilliscope views you might see what I mean.


edit: if nothing else and you want you can maybe put your hands together at a little building yoruself if you a good hand with a soldering iron

Gummie

Wow, lots of action. I'm going to say two things.

First, I'm far too lazy to read all the back/fourth posted here so I apologize if it’s been posted already.

Second, a good deal of music studio recorded music makes use of a clipped signal in the final cut. It's done for a number of reasons. It adds an interesting edge to audio, makes certain things sound louder (basslines especially), etc. A good deal of rock/metal bands use this method in the studio to tweak their sound and I’m sure that other genera use it as well.

I don't see why this wouldn't be done in a live environment (ie guitar amp) where the clipping won't be introduced during a production phase at the studio.

A lot of what both you and I listen to has a clipped signal. Clipping a car amplifier is generally accepted as bad for subwoofers. Also, the JL sales rep guy (msomething) has written about driving their products to clipping but not that much further past when doing a number of writeups.

I’m not claiming to be an expert, but I don’t think the actual act of clipping is that bad. I guess it depends on what extent you take it to. Keep in mind that clipping means cutting the top off a sign wave, therefore you can have different levels of clipping (ie more/less). I would assume that more is worse.

Again, not an expert. I’m not sure anyone else is going to want to join the fray and post their 2 cents though

NEEDAZ

rx7speed gets the gold star for connecting the dots. Had to think about this one. I've always held onto distortion (over driving the amp) will kill a speaker. At the same time I know how the 'distortion effects’ work (former Fender/Sun, Martin authorized repair tech). The best answer I can come up with is that, on the equipment I remember, the ‘distortion’ was being introduced in the pre-amp stage. So as long the ‘volume’ isn’t all the way up, the ‘clip’ is well below rail voltage, so even though it is a clipped signal, it’s clipped at a low enough power that it’s effects (effectively dumping DC into the coil for a short time) are minimal. Keep in mind we all say DC kills speakers, but at a lower power level you can keep the DC there indefinitely. I’m certain that the high frequencies help a lot as well, but that doesn’t apply to the bass guitar.
Jim, you’ve got the theory in this end of things a lot better then I, any input?

Jim85IROC

iTrader: (2)

As far as I know, the distortion that's added in production or in guitar amps tends to be harmonic distortion, not clipping.

I'm not aware of any cases where signals are intentionally clipped, though I've never produced a record, so who knows. Harmonic distortion is commonly used in many cases though. Toss in some 3rd and 5th order distortion and your metal instruments (and electric guitar) get a raspy, edgy sound that can really make it sound more "alive". Maybe clipping can produce a similar effect, though I'm not sure. Even if it did, it would be done at a high enough frequency that I seriously doubt it would have the same kind of negative effects that clipping your sub amp has.

I have no idea why anybody would ever want to clip a low frequency signal. Often high levels of 2nd harmonic distortion can be added to give the bass a richer, fuller sound through any pair of speakers, but a clipped signal sure as hell isn't going to do that.

rx7speed

that clipping is what produces those harmonics that you hear in a guitar.


clipping is a form of distortion and this distortion is how you get your different harmonics by changing the shape of the wave. depending how you clip the wave can determine what type of harmonics you get.
pure square wave clipping is mainly odd harmonics. where the positive and the negative wave are clipping different amounts or only one part of the wave (either positive OR negative) will generate odd harmonics.

I'm at work right now and can't really explain that great being I'm taking call after call right now, but if you look at this website it has a nice little applet that allows you to play with how the soundwave looks and hear how it sounds and maybe you can see what I'm talking about


http://www.mindspring.com/~j.blackstone/dist101.htm

Jim85IROC

iTrader: (2)

Interesting. I'm going to bow out of this conversation now and just learn a thing or two.

rx7speed

try this one when you guys get the chance
a1 4.9
a2 1.2
the rest at 0
looks likek a clipped signal right?

prolly doesn't sound that different. I'm at work right now so eh.
but this adding of harmonics makes the signal looked clipped.
or driving your preamp/power amp against the power rails is going to cause the clipping also.
when your sub amp goes into clipping it's going to do the same thing.
also think of the term used by people who do music. ever heard the term overdriven? it comes from people overdriving their amp to get that nice distorted sound and push it into clipping

though generally it doens't sound that great with music being it clips things that don't soud good clipped. as far as harming the speaker I don't think it is going to do much though. worst one that would be affected I think would be a tweater. they don't really have much in the way of cooling. usually the sub and and or mid range speakers. if any of them would get hurt I would it would be tweaters. they don't quite have the range or cooling ability of subs do. most times the voice coil is surrounded with no venting and the speaker itself doesn't get much cooling by air done to it.


but also to those that say the clipping is going hurt the speakers. I'm wanting to know the difference between putting the gain on my amp full blast and clip the hell out of my guitar signal and then recording it and then playing it through my car system vs pushing my amp into clipping. how are the speakers going to see a difference in that?
to them isn't it a clipped signal either way?



I'm still not saying it sounds good don't get me wrong. only clipping I like is for my own playing. as far as music. give it to me how it is recorded not over driven.

lockchad

Just my 2 cents guys. May have been mentioned before but, here goes.... When you record a clipped or distorted signal it is not the same as reproducing clear sound to the limit of distortion.
Also speakers have a voice coil which is run by ever-modulating A/C power. When the A/C becomes over modulated it creates heat. A good example is to go look at you stove. A/C with given frequency that is too fast for inductation, D/C to A/C, lets D/C slip through. This in turn heats the voice coil like a heating element therefore deforming the "voice coil former". (Usually made of tin, aluminum, silicone or wound mylar). True these elements can withstand heat, but the voice coil usually has a protective varnish which "cooks" and expands. When this happens it locks up against the T-yoke which has limited room for the voice coil and former to travel. Then POOF. Hopefully when this happens it does not create a direct short and take out your amp.
All of this can happen regardless of power, high or low. Mid-ground is the only safe area. Always match your equipment by RMS. This is the rating in which your equipment will stress least.

Also a tidbit. You can get a good idea of how much power your amp has the possibility of putting out by figuring a couple of things. IxE=P. In other words I=amps X E=voltage = P=wattage. (Ohms law)
Take your fuses or fuseability rating of the amps. Multiply that by your common load output of voltage (normally 11.5V with a few accessories running). And Viola! The most wattage your amp can ever produce. Divide this by 1/2 for your RMS.
So, an amp with 2 25amp fuses has a 50 amp load rating. Multiply by 11.5v and you have an amp that can put out 575 Watts. On its best day.

Excuse my rant but I was in the car audio manufacturing and installing field for 8 years. Excuse any terminology infarctions, its been awhile.

rx7speed

I'm not sure if I am following you with the over modulation thing. or the stove reference. you don't need D/C to heat things up. A/C can do a good job of it also. part of the tubes I use are A/C heated on the cathode or on the heater filiment itself depending on the tube. the only D/C heat would come from the bias current which generally wouldn't be enough to heat the cathode up enough to allow electrons to flow.

as far as the voice coil and overmodulation can you go a little further in depth as to what you rtrying to say there. I'm not quite understanding. from what it sounds like your saying is when pushing the amp to far it goes into clipping and allows the wave to go more into a square wave it allows a DC current to appear to go through the voice coil. thing is though when your playing clean but playing a clipped piece like someone playing metal guitar it has the same wave form and would allow for that same clipped square wave which shoud let dc current go right?


also RMS rating isn't half it's .707 if I remember right or .787v of peak to peak when using a pure sine wave. one thing too give food for thought is very little music is pure sine way so actually rms voltage might be a little different if you rate it on true rms

9177

Back to the topic how big is your power wire going to the amp? is is connected directly to the battery or elsewhere? how big is the ground and where is it attached to.

techno101

The power wire is hooked directly to the battery. And the ground is about 5 feet long and is hooked to the back seatbelt nut, grounded to the chassis. I'm pretty sure I figured out what happened. The sub woofer I'm using has a lot higher RMS wattage than I thought. The amp that I have,turned up as high as the gain will go, is probably only pushing half of the RMS wattage for the sub. Very large mistake on my point. Buts thats how you learn right?

lockchad

Rx7, sorry about the confusion. Ok, here goes, when you put dc current through a wire coil it creates a stove effect. A/C is good enough, but the frequency switches so fast, in sound reproduction, that it doesn't allow heat to build. DC will do it quickly, especially when you have very little resistance i.e. 4ohms or 8ohms.

The clipping thing has to do with the translation of what the amp has the ability to do. The amp sees signal indiscriminatly, send it good sound, it produces good sound. Send it bad sound, it'll produce bad sound, in a safe way. Until you drive the amp into clipping itself. It will then amplify the clipped signal without protection. An amp will safely reproduce signal until you go out of its safety zone. There's a term for this, and a rating, but i can't remember what it is. I do know it's connected to the amps THD rating.

We're probably talking about the same thing in different terms. Mine=manufacturing monkey/installer, Yours=Electrical engineer.

Good call on the rms thing too. All true. I just always use 1/2 as a safe measure, especially when you're selling the stuff retail. Gotta dumb it up.

Gummie

Cranking the gain all the way means that you will max out the amp before you max out the headuit. This leads to clipping and will drive an amp into protect mode causing it to shut off and turn back on when it thinks it's safe to do so again. Turning down the amp will solve the problem while yielding less output. Buying a bigger amp is probably the better solution in your case.

Check out this link for a better explanation.

Incidentally, RMS rating of the sub doesn't matter for making an amp clip. It just means that your sub can handle more power.

PhLaXuS

I've done a bit of recording in studios and on my own and can say that most of what I'm reading in this thread is true (but it's late so I may have missed something), but the whole of what has been said has not been brought together. Basically, as I have experienced it, "clipping" in mobile audio is interchanged (incorrectly) with the term "distortion". Clipping spefically in mobile audio means simply to overdrive a gain circuit so that the output is slammed all the way against the reference rail voltage of said gain circuit. Pretty much looks like a square wave. Distortion, as in a guitar effects box, can look MASSIVELY different from one box to the next and even from different modes of the same box. Point is, regardless of how the distortion is created, I've never seen a waveform from ANY effects box or other piece of studio equipment which resembles a square wave. Now, let's take a Boss DS-1, for instance. I haven't seen the schematic or cracked it open, but it probably does overdrive the signal into a square wave at some point, but further modulates it so that the output jack on the box is simply sending a modulated signal and not a purely clipped one. You can mimic a lot of the effects of clipping with a compressor, but in this case, it's a safe form of pseudo-clipping. A highly compressed signal recorded at 0 dB gain looks very much like a clipped signal, but the duty cycle at rail voltage is not high enough to cause voice coils to overheat & fry.

For a quick demonstration, open a WAV recorder on your PC and check the waveforms you're pulling out of your different effects boxes. This is not a really good method, but it gives a nice visual clue as to what's going on...

rx7speed

I've been using a cheap oscilliscope program hooked up to my sb live. i see many different thing depending on the design. most my tube amps have been fairly soft on the clipping. rather then having a square wave or even just make it look like it's just chopping the top of the wave off most of them seem to be smooshed or compressed. but a few I have put together will clip one of those waves very hard and go into some weird pulse widt modulation also.

with IC, and transistors though I have had some that go damn near into a square wave but more often then not still hit the power rails and get a flat top to them. or if using diodes a lot of times those look fairly well choped at the top.


but they could be mixing in part of the clean signal with the clipped signal to help soften things out. there are many different thigns you could do with the distortion.

so while it might not look like a square wave as in perfect square many times the top or bottom of the wave can still be clipped. it all depends on how much gain is used to do the distortion. the gain could be high enough to clip the top part of the wave but still not be a square wave. if you understand what I'm saying.

NEEDAZ

What you described with the distortion you see over driving tubes is something they’re known for, among other things.
I can only speak directly to one ‘distortion’ circuit that I recall. It was just an op-amp in the pre-amp that you could rap the gain way up on and over drive that stage. But even with this stage ‘all the way up’ I don’t think it was anywhere near over driving the output stage, so total power out would have still been low.
Rx7speed, what is the lowest frequency you think you’re seeing with a base? What about with a guitar? I think this is going to come down to what the total average power out is at what ever frequency and for how long.

In the end, over driving your amp is bad. Turning the gain on the amp all the way up will almost certainly have you over driving your amp. You will NOT damage a speaker giving it too little power.

rx7speed

few thigns and one of them I admit don't know why I didn't think of this.

overdriving the power amp needaz I have done. seems to get a slightly differnt sound out of it.

as far as power output
most ratings are done in RMS which is .707% of peak voltage when based upon a sine wave
so when you compare a square wave vs a sine wave with a peak voltage of 1293watts
both would then have a RMS value of 1000watts again based upon the sine wave.
but the problem comes with the square wave the true actual wattage is the 1293 watts being while the sine wave isn't transferign full power all the time while the square wave is.
so while both might have the same peak wattage at one instant but avg power on the sine wave is less

if I had access to paint maybe I could show you there.


but maybe you guys might be able to understand what I'm saying there.
but even in taht situation if the peak wattage of the amplifier not higher then the peak wattage of the sub it still shouldn't cause a problem.


that's one problem with rating things. too many ratings. you have peak wattage, rms wattage, true rms and who knows what else

lockchad

AMEN, thats why i really like the new standardized CEA 2006 rating scale. Sanme stuff Rockfords been doing forever.

PhLaXuS

rx7speed,

I tried posting today on my lunch break, but the computer I was on had problems & the post didn't go through. I was going to say pretty close to what you just said in your last post. I said something to the effect of:

The only way a "bad" signal can blow a voice coil is if the extraneous waste heat created from driving the VC is too much to dissipate. This is why you can send a square wave of low intensity through a speaker and not have a problem. It's all about average power over a short time frame (just a few seconds). It's also why it's SO much easier to blow a sub from clipping: because bass has such a low frequency, when you clip, the rail voltage into the VC is is most likely occurring at a much greater duty cycle then at a higher frequency. You can clip the crap out of a midrange speaker and it'll probably live through it without a problem. Also, clipping is less noticable from the subs, so people have a tendency to crank it well above what would be considered "musical" from a midrange speaker.

So...in a sense ratings do play a part in this because higher current handling VC's can dissipate more heat and can tolerate clipping much easier from a lower powered amp (i.e.: a sub rated @ 800W RMS driven by an amp which can only put out a max 100W clipped signal may not kill the sub because it should be able to dissipate the heat.).

rx7speed

only two thigns I have to say.

duty cycle shouldn't change just cause of frequency. a pure sine wave should still have a 50% duty cycle as a square wave can have a 50% duty cycle. think of duty cycle as how much time it is positive vs how much time it is negative as easy way to put it though I think I know what you are refering to. just using a different word.



two I HATE FORT LAUDERDALE... HATE HATe HATE. I book travel for a few travel reward credit card programs and EVERYONE wants to go to FLL or want to go to west palm.

PhLaXuS

Agreed, but (assuming a sine wave) because the wave at low frequencies is so slow and lazy in shape, when you clip the peaks of a bass signal, it is easier to attain a clipped waveform for a longer sustained duration of time each cycle. Clipping the same upper 10% (arbitrary %) of a 1kHz sine wave results in a signal which is clipped the same period of time per cycle, but the clips are smaller and further spaced apart -- allowing at least some extra "time off" for the voice coil to cool down.

P.S. I don't mind Fort Lauderdale. It's considerably better than where I moved here from.

PhLaXuS

20Hz Signal, 0.1 Seconds In Duration, Upper 10% of wave clipped. This pic shows ~0.026 seconds of the waveform clipped & 0.074 seconds not clipped.

PhLaXuS

1kHz Signal, 0.01 Seconds In Duration, Upper 10% of wave clipped. This pic shows ~0.0026 seconds of the waveform clipped & 0.0074 seconds not clipped.

rx7speed

percentage wise though they both are spending the same amount of time doing their "cool down" and the same amount of time at peak power.

so overall avg power between the two should be the same.


what program is that and is there a way I might be "able to get my hands on it"

NEEDAZ

OK, so dump both signals into the same speaker and the power will NOT be the same at 1KHz. You will see considerably less power at 1KHz Vs. 20Hz. A speaker is not a purely resistive load, it also inductive. So given the same P-P voltage at the higher frequency current will go down and subsequently power will go down. It important to consider the difference between resistance and inductance. That is why you would be safer at higher frequencies, not because of duty cycle. I’ll add to remember that a square wave with a 50% duty cycle still delivers power 100% of the time, that’ll build some heat.

rx7speed

hey hey I ended up correcting myself on the square wave thing


didn't think about the whole inductive thing which I shoudl of being gee... vacuum tubes and well now what do they use??? transformers and tehy have what? inductance..




sorry it's been a long week.
and their resistance can vary by quite a bit at least with subs from less then a ohm I think I have seen up to 60ohms at their peak.



but here is a question for you needaz what happens when the output source has a negative output impedance?