Now Iblew the tweeter in the other R50?

[BrettSelinsky]

I had blown a tweeter in my new R50's about 2 weeks ago. Well I thought the problem was my cheap a-- Sony reciever. So, I bought a new Yamy RX-V2500. WOW! What a difference. The sound is so much cleaner and better. But, I blew the other tweeter last night???????? I was playing it pretty loud (over 1/2)but the sound wasnt distorting or anything. And I had no clipping at all. Just quit working?
Polk sent a replacement tweeter at no charge ( and I really appreciated this / great customer service). And when I opened the box they sent me 2 replacements. So I do have a replacement for the one I just smoked.
Well to get to the point, I wonder If it was just a bad lot of tweeters and they sent me 2 because they've been having a problem?? And, if I do keep having this problem what tweeter would one recommend for a replacement for the tweeters that come with the R50's. I have RT15i bookshelves in the rear. Are they a better tweeter? Should I swap them?
Hopefully they were just a bad lot of tweeters.
What actually happens when a speaker blows? When I barely touch the center dome on the tweeter it comes back on? Just wondered?
Sorry so long winded.

Thanks
Brett

[hoosier21]

playing music OVER 1/2 or past 12 oclock (older equipment with analog volume control) will bring on clipping, I thing you fried the second tweeter just like the first one.

Turn the volume down, it is unrealistic to think you can play concert levels and not kill something in the system. No offence, but but 500.00 speakers and a 600.00 receiver will not play that loud without clipping. Clipping equals dead tweeters.

[BrettSelinsky]

Ok I shouldnt have said half. It was -13dB. Is that too loud. Is that over half? And no offense taken but this $600 receiver and $280 speakers really sing clearer than anything I have ever heard. I couldnt imagine what you guys are hearing with your systems. But I have to start somewhere.

Thanks
Brett

[danger boy]

congrats on your new Yammy.

My friend kept cranking the volume on his Onkyo and kept blowing tweeters in his CS400i. after three blown tweeters he finally gave up and went with another brand of center speaker. no more blown tweeters.

i can't say why some people experience lots of blown tweeters and others don't. I can only guess it's by playing the volume loud for extended periods of time.. like for hours and high volume. that was his case.. it may not be the same with yours however.

[Tour2ma]

Doesn't necessarily take hours... driving a speaker to near it's limits will progressively warm voice coils and as it does the impedance drops. Dropping impedance demands more current, generating more heat, etc... until clipping occurs. And sustained clipping kills tweeters...

If rock is your music of choice, its relative lack of dynamics feed the above cycle very well... and fairly quickly...

The 2500 at 130 wpc, albeit near the top end of the recommended range for the R50, is a mid-power AVR, and I see nothing to indicate that it has significant current reserves beyond its power rating. You have not commented on it here, but I'd be willing to bet the your AVR is getting hot during your listening sessions and this would indicate that you are reaching its limits...

Listening at lower levels is the only solution with the gear you have, but you can rearrange your listening to help regain some volume... namely move closer... Halving the distance between you and your speakers will increase the SPL by 6 dB. So you can set your AVR to -20, rock on and see if everything holds together.

[madmax]

Another possibility is that the second tweeter was damaged but had not given out yet. Before they blow the coil wires get very hot and sometimes short together. They may still play that way but tend to get even hotter with less power. I think you probably damaged both tweets with the sony.
madmax

[Tour2ma]

Good observation, max...

I'd still urge caution in approaching the listening levels at which the last failure occurred, but it is possible that the Sony set up tweeter failure #2...

[BrettSelinsky]

Mad max and Tour2ma I think your both right. I went home turned it on put a cd in turned it up to -13 and off went the tweeter in about 20-30 secounds. I really think the Sony may have got both of them. I just cant believe it was at to load a volume because it was not shrill sounding at all and it was a very pleasing volume. Can you hear clipping?

[steveinaz]

Your tone controls are set to flat correct? Increasing treble past 0dB can also contribute to blown tweeters.

[Tour2ma]

Clipping is sometimes accompanied by audible distortion, but it's major component is ultrasonic, in the 100 kHz area.

When a tweeter tries to reproduce this high of a frequency (as opposed to the normal upper limits in music of 20 kHz or so), it overheats and "fries".

Replace the 2nd bad tweet and approach with caution...

[madmax]

You can hear it when it is way too much. The problem with cheap amplifiers of the sony range of power (not sure of exact wattage but close to the speaker limits) you end up not having enough power to stay away from distortion but yet have enough power to do damage before realizing it. There are two ways around this. One is to go with really low power and the other is to go with really high power. That may sound strange but with a much higher power (300 to 1200 watts) you can drive the speakers much louder with no distortion and little chance of damage.

Tour brought up another point that there are differences in music also. I have power meters on my equipment and I've noticed some music stays very low with huge peaks. That is very speaker friendly. Other music is constant and the meters don't jump around very much. (same continuous sound level throughout). With this type of music you have to watch your power setting much closer. I'm sure you can figure out which music is which and keep that in mind.

madmax


edit: Tour and I are always right except when we argue with each other in which case I'm always right. :D

[Tour2ma]

max,
We've been agreeing wa-a-a-y too much lately... ;)

[madmax]

Read my edit on the previous post. :D

[Tour2ma]

LOL... That EDIT could be "quote" worthy...

[MacLeod]

Technically, clipping isnt what kills speakers. A speaker doesnt know the difference between a clipped signal and any normal one. It doesnt know the difference between a distorted or clean signal either. The thing that kills the speaker is too much power.

When an amp clips it can produce as much as twice its normal power. Say an amp rated at 100x2 @ .08% THD clipped would produce something like 200x2 @ 10% THD. So if your speakers are rated at 300 watts, you could clip this amp all day long and not hurt the speakers. That 10% is also why people mistakenly associate distortion with dead speakers when it was the doubled power that was the culprit.

So when you turned up your amp into clipping, it doubled its power output and thus ended the life of your tweeter.

Getting a bigger amp can only help in that youre less likely to clip it because you have more headroom and are more likely to get it loud enough before the amp clips. However, if you get a 150x2 amp and stick it on 50 watt speakers, you can kill them with a super clean signal just as easily and quick as a dirty distorted one.

[hoosier21]

MacLeod, that post is very confusing, and has some bad information in it.

Clipping

Amplifier distortion occurring when a high energy wave form (a very loud sound resulting in a large output) is input into an amplifier and the amplifier is unable to fully reproduce it due to power supply limitations or amplifier design limitations resulting in the audio output waves being cut off (the rounded tops sliced off resulting in short waves with flat tops). Clipping creates audible distortion and can be damaging to speakers especially if the clipping is hard and frequent.

Clipping generally occurs when an amplifier is playing at a high level and it is asked to output a large amplitude waveform (“tall” wave with lots of power). The amplifier clips when it does not have the power capability to correctly create the waveform. Instead, as the wave is built it hits a ceiling essentially not allowing the wave to go any higher. Since the amplifier cannot recreate the remaining portion of the wave rising above the “ceiling,” the wave is cut off.

Generally, the more power an amplifier has (especially relating to the quality of the amplifier’s power supply) the more immune it is to clipping. For this reason, larger amplifiers tend to provide better quality sound at loud listening levels since they clip less often (if at all) compared to similar but less powerful amplifiers.

Clipping may be heard in loudspeakers as an abnormal, non-musical sound. It is unpleasant and it may damage speakers (with tweeters being particularly susceptible). This occurs because a speaker cannot produce the flat-topped waveform sent to it by the clipping amplifier.

In order avoid clipping, do not play a sound system at excessively loud levels and make sure the amplifiers being used are large enough to recreate the sound levels in the given space. Generally, use the largest amplifiers reasonable, as they are less likely to clip and damage speakers. It is much more dangerous to clip loudspeakers by using a small amplifier lacking in power than to use a large amplifier even if that amplifier’s power ratings are greater than those recommended for a given speaker (distortion, and clipping in particular, causes damage not clean power from a quality amplifier).

[hoosier21]

good read

http://sound.westhost.com/clipping.htm

[Tour2ma]

Originally posted by hoosier21
MacLeod, that post is very confusing, and has some bad information in it. Agree... Does not agree with my readings on the nature of clipping.

And one side point in particluar about speaker ratings is inaccurrate. Speaker ratings are nominal ratings. Speakers can handle transients that many times their nominal rating. Julian Hersh showed this time after time for a couple decades.


Originally posted by hoosier21
Clipping

Since the amplifier cannot recreate the remaining portion of the wave rising above the “ceiling,” the wave is cut off. Yup... turns a sinusoidal input into something approximating a square wave output.

Source I read decades ago went into the examination of what happens to the unreproduced input, i.e., the peaks that are "clipped" off. Their measured result was the creation of the ultrasonic element I referred to above.

While the cause of clipping is amp power limitations, this is usually associated with bass demands the amp is unable to meet. However, the impact of clipping falls upon the tweeters.

[MacLeod]

Originally posted by hoosier21
Clipping

Amplifier distortion occurring when a high energy wave form (a very loud sound resulting in a large output) is input into an amplifier and the amplifier is unable to fully reproduce it due to power supply limitations or amplifier design limitations resulting in the audio output waves being cut off (the rounded tops sliced off resulting in short waves with flat tops). Clipping creates audible distortion and can be damaging to speakers especially if the clipping is hard and frequent.

Clipping generally occurs when an amplifier is playing at a high level and it is asked to output a large amplitude waveform (“tall” wave with lots of power). The amplifier clips when it does not have the power capability to correctly create the waveform. Instead, as the wave is built it hits a ceiling essentially not allowing the wave to go any higher. Since the amplifier cannot recreate the remaining portion of the wave rising above the “ceiling,” the wave is cut off.


Agreed. I didnt say anything contrary to this only added that when an amp clips it is making as much power as it possibly can given its input voltage which is usually double what it normally puts out at normal listening levels.


Generally, the more power an amplifier has (especially relating to the quality of the amplifier’s power supply) the more immune it is to clipping. For this reason, larger amplifiers tend to provide better quality sound at loud listening levels since they clip less often (if at all) compared to similar but less powerful amplifiers.

Yup, agree with that too. But all amps will clip eventually. Its just that with more powerful amps you dont need to push them that far.


Clipping may be heard in loudspeakers as an abnormal, non-musical sound. It is unpleasant and it may damage speakers (with tweeters being particularly susceptible). This occurs because a speaker cannot produce the flat-topped waveform sent to it by the clipping amplifier.

This I disagree with. A speaker will produce a flat wave just as it will produce a sine or triangle wave. Its not the shape of the wave that is hurting the speaker but too much power. Go get you a 1000 watt sub and hook a 100 watt amp to it then clip the hell out of it. Itll sound like crap but the sub wont even whimper.


In order avoid clipping, do not play a sound system at excessively loud levels and make sure the amplifiers being used are large enough to recreate the sound levels in the given space. Generally, use the largest amplifiers reasonable, as they are less likely to clip and damage speakers. It is much more dangerous to clip loudspeakers by using a small amplifier lacking in power than to use a large amplifier even if that amplifier’s power ratings are greater than those recommended for a given speaker (distortion, and clipping in particular, causes damage not clean power from a quality amplifier).

I disagree with this too. Again its not the distortion or clipped single that hurts the speaker. You take 150 watts of super, shiny clean power from the best amp on the market and run it thru a 50 watt speaker and youll kill it just as if youd ran a crappy Kraco amp signal thru it.

[Tour2ma]

I was editing, while you were posting...

I disagree with your disagreements...

[MacLeod]

I dont understand why this is confusing.

I agree with everything you guys are saying other than its not the distortion or the squared wave that hurt a speaker, but rather the substantial increse of power at the point of clipping. If the increase is within the power handling of the speaker tho, itll just shrug it off.

100 watts of pure distortion wont bother a speaker capable of handling 200 watts.

I hope some of my car audio homies come over here and help me out. Im getting outnumbered! LOL :p

[Tour2ma]

Rallying the troops, eh? :)

I'm really arguing the ultrasonic created being the destructive force associated with clipping.

Clearly the only way to avoid clipping is to stay within the limits of a given amp. So if you want louder, you have to go with more power and exceeding the rating of a given speaker should be a non-issue in a home application where your ears should protect your speakers and you. Car audio differs when the objective of being the loudest on the block is added...

As for the waveform.... let's use your car as an analogy...

A sine wave is like gradually accelerating in the forward direction, holding a speed for a bit and then slowing to a stop before going into reverse, accelerating, sustaining, slowing and stopping then going into first and repeating.

A square wave is full speed forward, dead stop, full speed in reverse and repeat.

A triangle wave is full speed forward, full speed in reverse, etc.

It's easy to how mechanically destructive the latter two are for a car vs. the sine wave. The same is true for the drivers in the loudspeaker.

[MacLeod]

This is fun. I Havent had a good debate in a while! :)


Originally posted by Tour2ma
As for the waveform.... let's use your car as an analogy...

A sine wave is like gradually accelerating in the forward direction, holding a speed for a bit and then slowing to a stop before going into reverse, accelerating, sustaining, slowing and stopping then going into first and repeating.

A square wave is full speed forward, dead stop, full speed in reverse and repeat.

A triangle wave is full speed forward, full speed in reverse, etc.

It's easy to how mechanically destructive the latter two are for a car vs. the sine wave. The same is true for the drivers in the loudspeaker.

That is a good analogy so Ill stick with it.

Say you accelerate to 25 MPH, then stop then reverse to 25 MPH. Big deal.

Now accelerate to Mach 1, stop then reverse to Mach 1. Squish!

Same with the clipping. If the clipped signal is at 500 watts and the speaker is able to handle 200 watts, squish. If its a 500 watt speaker and the clipped signal is at 200 watts then the speaker will have no problem.

There are only 2 things that will kill a speaker. 1- pushing the cone further than the suspension can handle. 2- Giving it too much juice which builds more heat than the speaker can dissipate.

The shape of the wave has no effect on either of these. Take a 500 watt speaker. A 200 watt signal, clipped and distorted all to hell wont make a dent. A 1000 watts of pure, clean, sonic goodness will tear it to shreds.

The shape doesnt matter. If the movement of the cone is within the suspensions limit and the power is less than the limit of the speakers ability to dissipate the heat then the clipped, distorted signal will not hurt the speaker.

So, again, Ill take an Orion H2 sub, capable of handling well over 1500 watts RMS, and you take a 100 amp and clip it til the cows come home and that badass Orion wont so much as be tickled.

Yeah, who's ya daddy?! :p

[MacLeod]

Since Im on the subject of the badass Orion H2, check out this video. (http://www.realmofexcursion.com/videos/Orion/h212.1.wmv)

I dont care what kind of audio youre into, home theater, home audio or car audio, this is just cool! ;)

[danger boy]

well maybe the tweeters can't handle the same amount of power given to them as say a mid driver or a woofer. or else maybe something in the crossover got fried when they were pushed that hard.

[Tour2ma]

db,
Actually tweeters can handle remarkable amounts of power.

McL,
You're talkin' subs, and saying speakers and meaning subs
... I'm talking tweeters...

Been saying all along... Clipping kills tweeters ...
It's the #1 cause. Far more prevalent than overpowering them.
It's what this thread is about...

Sub's... different story... Even inside the house, subs are killed by being overdriven, bottoming-out. A sub won't even try to reproduce a 10 kHz signal, let alone a 100 kHz.

We are in agreement about heat being the culprit in voice coil destruction. I am saying is that if you ask a tweeter to reproduce a 100 kHz signal, an artifact of clipping an amp, it will "melt down" trying... A single, pulse of power will not have this effect.

Meanwhile back at the analogy...
Rate of change of direction is most important to mechanical devices which cycle. If you don't think so, then just get rolling at 5 mph and then throw your car into reverse.

[danger boy]

I think you're right.

my friend who kept frying tweeters was clipping his receiver now that i think of it. it would some times shut itself down. just recently he added a 2 ch. amp and he hasn't had that clipping problem anymore. huh. go figure.

[steveinaz]

Far more tweeters are toasted due to not enough power, than by too much---due to people pushing their under-powered amp too far, causing clipping.

Now, if this has changed for some reason in the last 40 years, I'd like to read about it....

[BrettSelinsky]

Had the house to myself last night and did a little test. Ran that Yamy at -13dB to -7dB for about 1 1/2 hrs. No problems at all. Im almost positive the Sony got both of them. I wouldnt have done it but it was driving me nuts because there is no sound distortion at all and it sounds sweet. I cant believe the difference in sound between the two receivers.

Thanks

[madmax]

Originally posted by MacLeod
I dont understand why this is confusing.
LOL :p

I'm not sure why you are confused either. Better get some of your car audio buddies in here. They can learn too. :)

Just kidding. In any case I can play my LSi7's with 600 watts per for hours. Good clean power.

madmax

[Tour2ma]

Glad to read you're back in business Brett S....

Slept on this overnight...

Originally posted by MacLeod
Now accelerate to Mach 1, stop then reverse to Mach 1. Squish! What was getting me were two questions:
- can something moving slower than the speed of sound create sound??? and...
- does a driver move at the speed of sound???
Let's see...

Speed of sound is around 770 mph or 1130 fps or 94 ips...

If a woofer is moving 1/2" total distance per cycle (not a big excursion... 1/8" out and 1/4" in and 1/8" out to return to starting position) in a response to a 30 Hz (pretty slow) sine wave input, it moves:
1/2" x 30 cycles per seond = 15" per sec
Of course this is an average speed since each cycle includes periods of acceleration and deceleration. Maybe the max speed is 20 ips, but this is still not the speed of sound... Hummmm.... I'd think you'd hear this :rolleyes:, so lower than speed of sound movement does make sound... Makes sense that the two are unrelated as the speed of sound through a medium is just its transmission rate and is not dependant upon the speed of the wave being transmitted...

As to the second question...
For the above excursion we'd have to reproduce a 141 Hz signal for the driver to reach the speed of sound... getting up there for a sub, but doable...
Of course 70 Hz with twice the amplitude (1/4" excursion, or 1" total travel per cycle) gets you to the speed of sound...

Bottom line... drivers do reach speeds of Mach 1...

Originally posted by MacLeod
Yeah, who's ya daddy?! Want my addy so you can send me a Father's Day card??? :D

[madmax]

Tour has finally lost it.

La la la la la la la la la la la land....

madmax

[F1nut]

Originally posted by madmax
Tour has finally lost it.

La la la la la la la la la la la land....



Yeah, what he said! ;)

[Tour2ma]

Originally posted by madmax
Tour has finally lost it.

La la la la la la la la la la la land....

madmax No wonder I started agreeing with you... :D

[MacLeod]

I feel so alone! ;)


You're talkin' subs, and saying speakers and meaning subs

Im saying speakers and meaning ANY speaker. I just keep using subs cause how many 1500 watt tweets you seen around? LOL A tweeter capable of handling 200 watts wont be hurt by an amp clipping at 100 watts.


Been saying all along... Clipping kills tweeters ...Far more prevelant than overpowering them.

When an amp clips, it puts out about double its power rating. This is what kills the speaker. If the clipped signal is under the speakers power handling, the speaker wont be hurt.


my friend who kept frying tweeters was clipping his receiver now that i think of it. it would some times shut itself down. just recently he added a 2 ch. amp and he hasn't had that clipping problem anymore.

Right because he doesnt have to turn it up as much to get to the volume level he wants. But, rest assured, if that amp puts out more power than the speakers can handle, it will fry those tweeters jsut as quickly as the crappy amp did because when the crappy amp clipped, it doubled the power and pushed the tweeters beyond their limits.


Far more tweeters are toasted due to not enough power, than by too much---due to people pushing their under-powered amp too far, causing clipping.

Go install a set of 150 watt Polk MM6 components in your car and power them with the cheapest, crappy 10 watt per channel head unit you can find. Turn it all the way up to max and youll never fry those speakers. Why? Cause even in clipping, that head unit wont put out any more than 25 watts or so which is about 125 below the limits of the MM6.


Now, if this has changed for some reason in the last 40 years, I'd like to read about it...

Well, here (http://www.welcometotheden.8k.com/caraudio/clipping.PDF) is some good reading by Richard Clark, one of the most renowned engineering gurus in car audio.

Cody, Joel! You guys get your asses in here! :p

[F1nut]

Originally posted by MacLeod
I'm saying speakers and meaning ANY speaker. I just keep using subs cause how many 1500 watt tweets you seen around? LOL A tweeter capable of handling 200 watts wont be hurt by an amp clipping at 100 watts.

I've killed a few tweeters and have known others that have too. It was always done with underpowered amps. I've never cooked one with high quality, high powered amps, never. What happens to a tweeter when it's underpowered vs overpowered is very different. When underpowered and clipping (distortion) occurs the voice coil cooks, when feed too much power a tweeter will basically explode, sometimes in flames.


When an amp clips, it puts out about double its power rating. This is what kills the speaker. If the clipped signal is under the speakers power handling, the speaker wont be hurt.

Clipping is distortion and distortion is what damages a speaker.

[Tour2ma]

High frequency...
There is another consequence of operating an amplifier into clipping: high frequency harmonics will be generated. Any time a signal is clipped, the waveform's spectrum (frequency components) will be altered. The result is that more high frequency energy is generated (as compared to what was present in the signal to begin with). The crossover in the speaker system will direct the higher frequency energy to the midrange and tweeter speakers, and these (especially tweeters) will be more susceptible to burnout.

The risk of damage to the speakers depends on the characteristic of the music (does it have lots of high frequency energy to begin with?), to what degree of clipping is occurring and how conservatively the speakers are rated. It is not uncommon to blow tweeters when operating an amp into clipping.

With average music material (and typical crossover frequencies for a 3-way speaker), about 70 percent of the amplifier's output energy is directed to the woofer, maybe 20-25 percent to the midrange, and 5 or 10 percent to the tweeter. If clipping occurs, the power to all speaker components increases, however the ratios given above change (such that the midrange and tweeter end up trying to deal with more than their share of the power). As should be fairly obvious, this can lead to premature failure of the midrange and/or tweeter. From a pretty fair write-up... http://www.rocketroberts.com/techart/powerart_a.htm

The author does discuss the increase in amp power at clipping, but it is RMS power that rises owed to the amplifier compressing the music signal through.... taadaa... clipping...

[Tour2ma]

Oh, and I read the pdf partly by Mr. Clark, partly by David Narvone (another guru?)... Clark says "subs" about three time in the first two paragraphs, but I hung in there...

Narvone does mention "extra 3 dB of energy... 1 dB is higher frequency" (quote approximated due to inability to cut and paste from pdf's), but blows it off by implying it is not meaningful to come movement... Gonna guess he's referring to a sub here...

And there's plenty of square wave talk... Can't fathom the belief that it is less stressful on any driver than a good old sine wave...

Anyway... I think we can all agree on two things:
- clipping is not good.
- heat damages voice coils...

Any increase in current to a voice coil increases the amount of heat it will have to dissapate.
Power, high freqency material and distortion all increase current flow...

What we disagree on is what is the most significant source if undesired current...

And don't think I failed to notice how you ignored the Mach 1 analysis I did...

Now go sit in your car...

[steveinaz]

The article you posted is addressing subs---again. Subs can take enormous amounts "raw" power and survive. Tweeters cannot. In fact you'd be amazed how much power a table radio speaker can take before failure, even though most of those are rated in "tenths of a watt."

The issue here is tweeters and amplifier clipping. True, amps do produce wattage far beyond their rated output beyond the on-set of clipping---the kind of power you light light bulbs with; but it's the overload of ultrasonics that fry the tweeter--ultrasonics induced by clipping.

[PolkThug]

Yeah, but will Brett Selinsky blow a third tweeter?:p

[madmax]

Originally posted by MacLeod

When an amp clips, it puts out about double its power rating. This is what kills the speaker.

I really don't know where you got this rule of thumb but it is wrong. When the amplifier clips it produces a square wave output which can be many times the specified power. Another thing to keep in mind is that speaker manufacturers have a lot of data to consider before putting a power limit spec on a speaker. How they do it can be varied.

madmax

[PolkThug]

Richard Clark kicks butt, he put a lot of people/manufacturers in their place with the amp challenge.

[steveinaz]

OK, do this:

Take a 35 watt receiver (any brand) connect it to a tweeter. Gradually turn up the receiver until the tweeter dies. Using an SPL meter measure how loud the tweeter played.

Take a 200 watt power amp, do the same. I'll bet you my next months paycheck that the tweeter will play far louder before giving out on the higher wattage amp.

It isn't clean power that kills tweeters, it's clipped signals. Though you can blow a tweeter with brute force watts, no doubt--but clipping will blow it long before brute force power comes into play.

[Tour2ma]

steve,
Even I'd have to take that bet with no x-over in play... ;) Especially since I no longer get a monthly paycheck...

[Tide]

Originally posted by PolkThug
Yeah, but will Brett Selinsky blow a third tweeter?:p

Does Vegas have a line on this yet? Who wants to guess the over/under on number of days until the next blown tweeter?

[Tour2ma]

Over/ Under??? We can e-mail PTI and get their take...

[TheReaper]

Originally posted by steveinaz
OK, do this:

Take a 35 watt receiver (any brand) connect it to a tweeter. Gradually turn up the receiver until the tweeter dies. Using an SPL meter measure how loud the tweeter played.

Take a 200 watt power amp, do the same. I'll bet you my next months paycheck that the tweeter will play far louder before giving out on the higher wattage amp.
The psychoacoustic theory of how clipping blows tweeters:

What happens is, once you start clipping, the amplifier can no longer amplify the loud part of the sound (the part that is being clipped). The amplifier can only amplify the softer part of the sound (the part that is not being clipped). In order to perceive the sound as being louder, the amplification of the softer part of the sound is greater, then amplifying both the loud part and soft part together (as would happen with a more powerful amp that is not clipping). The net result is, you are adding more and more power (continous power), to get less and less of a perceived volume increase, once an amp is clipping.

[MacLeod]

Clipping is distortion and distortion is what damages a speaker.

Clipping is distortion but distortion in and of itself doesnt hurt a speaker. If you have a 100 watt signal distorted all to hell playing into a 200 watt tweeter, itll never blow.


And there's plenty of square wave talk... Can't fathom the belief that it is less stressful on any driver than a good old sine wave...

The shape of the wave isnt the problem. If it is within the tolerance of the speaker it wont bother it. I.E. A 100 watt distorted, clipped signal into a 200 watt tweeter. Nothing happens other than it sounds like shit.


The article you posted is addressing subs---again.

No, its addressing speakers. Subs are speakers and work just like tweeters and midranges.


but it's the overload of ultrasonics that fry the tweeter--ultrasonics induced by clipping.

No, its the overload of power. Ill go back to my MM6 analogy. I can hook up my Alpine 15x4 head unit to my 150 watt MM6, turn the volume all the way to max and play it like that for years and never hurt those speakers.


I really don't know where you got this rule of thumb but it is wrong. When the amplifier clips it produces a square wave output which can be many times the specified power.

Umm...isnt that what I said?


Take a 35 watt receiver (any brand) connect it to a tweeter. Gradually turn up the receiver until the tweeter dies. Using an SPL meter measure how loud the tweeter played. Take a 200 watt power amp, do the same. I'll bet you my next months paycheck that the tweeter will play far louder before giving out on the higher wattage amp.

It isn't clean power that kills tweeters, it's clipped signals. Though you can blow a tweeter with brute force watts, no doubt--but clipping will blow it long before brute force power comes into play.

Ill take a 35 watt receiver and play it thru a 200 watt speaker (tweeter, mid, sub whatever) and itll never blow. But assume I hook it to a tweeter that dies at 50 watts. I turn up the 35 watt receiver until it clips. When it clips the power jumps to about 80 watts thus frying the 50 watt tweeter. Now take the 200 watt receiver and turn it up. Once it goes beyond 50 watts the tweeter dies. The reason it sounded louder was that a distorted signal isnt as loud as a clean signal but the speaker doesnt know the difference. All it knows is its getting 50 watts and once it goes beyond that 50 it dies, regardless if its clean or distorted.

The reason the "underpowering kills" theory got started is that most people dont power 500 watt speakers with 50 watt amps. If they did tho, it would never blow those speakers. Most people consider underpowering to be more like powering a 100 watt speaker with a 60 watt amp. This would kill the speaker cause youre more likely to clip the amp at which point the power jumps to about 130 watts and squish! It wasnt the clipping or the distortion. It was the 130 watts which was caused by the clipping.

Is anyone keeping score? I think Im losing. :D

[Tour2ma]

It's not a matter of winning or losing... it's a matter of convincing... and in case you have not caught on, you are not convincing me/ us...
I can hook up my Alpine 15x4 head unit to my 150 watt MM6, turn the volume all the way to max and play it like that for years and never hurt those speakers. You say "can". Have you actually done this? Not for years, but how 'bout an hour?

Part of the issue is your solution to clipping, i.e., grossly underpowering speakers, is practical only in the car audio world. Why? Because car cabin volumes (as in cu ft, not dB) are many times smaller than the smallest of man cave, home listening rooms. In cars, tiny amps can drive speakers to unbearably high SPL's. In homes you need more power.

So if the level of power you have leads to clipping, and you are unwilling to reduce listening levels, the only solution is to increase amplifier power.

[MacLeod]

It's not a matter of winning or losing... it's a matter of convincing... and in case you have not caught on, you are not convincing me/ us

In case you didnt catch on, it was a joke.


You say "can". Have you actually done this? Not for years, but how 'bout an hour?

Ive done it several times over the last several years and for extended periods. I used to drive around with a pair of MTX Road Thunder boxs (2 subs, 2 mids, 2 tweets) powered by a Sony 25x2 "power booster" :rolleyes:. I would drive around for hours with it cranked to the max. It was loud (screechy) as hell. Sounded like shit too. It was clipped and distorted as hell but those boxes never so much as whimpered. Why? Cause they could handle well over 200 watts and even tho that Sony was putting out one hell of a clipped and distorted signal, it never got anywhere near the limits of those speakers.


Part of the issue is your solution to clipping, i.e., grossly underpowering speakers

Oh come on! Do you really think Im advocating powering 150 watt speakers with 15 watts? Give me a little credit. I would never do that nor would I recommend doing that. Im just using it as an illustration of my point.

The only thing that kills a speaker is getting hit with too much power and either building up more heat than it can dissipate or being forced to move beyond the limits of its suspension. It doesnt matter if that signal is clean, distorted or clipped. If it is below the limits of the speaker, the speaker will be fine. If it is beyond the limits, then the speaker dies.

How 'bout we go out on common ground here:

A - A clipped signal is much more likely to kill a speaker than a clean one.

B - You should always power your speakers properly.

C - Too much power kills speakers.

:cool:

[F1nut]

There's one big problem with a lot of this post. People are not talking about the same thing. The problem is with tweeters, not entire speakers, not subs, just tweeters!

As such, it is a well known fact in the audio world that you will cook a tweeter easier and faster when cranking up the volume with a low powered amp rather than a high powered amp because the low powered amp clips easier and sooner. That is a indisputable fact.

[Tour2ma]

Jesse,
Still agree that grossly overpowered amp capability is the safest ground... at least where no small children, or (worse yet) teenagers or (worse yet) guys from NJ named Tony are around... :D

All,
I'm done arguing. Not because I am tired of it, or defeated, or because I can't convince anyone I'm right... OK, maybe a little due to this last point.. :D ... but mostly because I'm going for a deeper understanding. (Yup, Jesse, the Engineer is coming out... ;) )

I did a bunch of searching and reading today. Some of the sites I found have some pretty good science behind them; some had none at all. And while no one site provided a definitive treatment of the subject, cummulatively I think I came away with a better, more holistic take on the topic, but no firm conclusions yet. Now I am just trying to understand....

Mac,
Truce for now... but let's hold off on the common ground and just agree to holster our guns for now... Mmmm-kay?

Yup, I knew you were joking about the losing. But the "convincing" comment I made was meant. We're all just going round and round now, restating what we'd already covered. It's why I asked if you'd performed the clipping test (me, testing your convictions... you passed ;) ) and went off in search of "the truth"... but alas no Holy Grail of Clipping web-sites to be found...

Also trying to raise new discussion points is why I raised the question around your "low power" solution and followed it (in case you did not notice) with observations on the car audio world vs. the home audio world... just some new material, not meant to demean, but to stimulate and clarify.

Couple questions on your car test...
You said your speakers were 200 watt rated. This is an overall rating I'm sure, so do you know what your tweeters' rating was? Are they more in the 10 to 20 watt range?
For the Sony 25x2... was 25 watts the max or continuous rating?

More later...

EDIT: Almost forgot... we could just forget the whole thing and go with the POLK FAQ explanation...
http://www.polkaudio.com/home/faqad/q.php?article=whybreak

[MacLeod]

As such, it is a well known fact in the audio world that you will cook a tweeter easier and faster when cranking up the volume with a low powered amp rather than a high powered amp because the low powered amp clips easier and sooner. That is a indisputable fact.

I agree totally with this bro. With underpowering a speaker (say 50 watt amp to a 100 watt speaker) you will need to turn it up more to get the sound youre after. With the smaller amp youre more likely to turn it to the point of clipping at which point the amp makes around 120 watts thus killing the 100 watt speaker.

I think we're all in agreement about 99%. Where I differ is that I claim its the overpowering coming from the clipping , regardless of distortion, that is destroying the speaker and you guys claim its the square wave or distortion, regardless of the power, that is the culprit.


Couple questions on your car test...You said your speakers were 200 watt rated. This is an overall rating I'm sure, so do you know what your tweeters' rating was? Are they more in the 10 to 20 watt range?
For the Sony 25x2... was 25 watts the max or continuous rating?


LOL! I wouldnt exactly call that a test partner. More like me thinking Im the man cause my shit was loud. Didnt matter that it sounded like poop! The Sony "power booster :rolleyes: " was 25x2 RMS. Youre right that the rating for the MTX's was 200 RMS per box (1 sub, 1 mid and 1 tweet) and so I would agree with you that the tweet was about 10-20 watts. My point was tho that even tho they were getting a horribly clipped and distorted signal, it was well below their power handling and so didnt hurt it. There again my point being that distortion doesnt hurt speakers if its below their power handling.

All in all, I think we have argued this to death and as such should put it to rest. I dont want to start any bad blood. Ive always enjoyed a good intellectual exchange such as this and since none of my cowardly car audio homies see fit to come to my aid I think its time we move on to other things!

:p

[F1nut]

Speaking for at least Tour (I can speak for him since he played MJ on my big rig....ugh!!!) and I, no bad blood at all.

Carry on.

[Tour2ma]

There you go Mac... see how forgiving Jesse can be... Hee-hee :D

No bad blood here either... but my blood is up and my thirst for knowledge must be quenched... :cool:

"I'll be back..." - Tour2ma-nator

[MacLeod]

Bring it on! :p