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post #181 of 404 Old 06-11-2007, 12:40 PM
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Does the power handling specification refer to thermal or mechanical limitations?
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post #182 of 404 Old 06-11-2007, 12:56 PM
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Originally Posted by Megalith View Post

Does the power handling specification refer to thermal or mechanical limitations?

That's a very good question. I certainly don't know the answer.

I have no idea where the power handling specification for speakers comes from. Is it calculated? Is it an actual real, experimentally-derived result?

It's usually presented as a "round" number, like "200 w/channel" or "250 w/channel". You never see something like "237 w/channel".

Hmm. Hopefully someone will know the answer. I'm curious, now.

"All men are frauds. The only difference between them is that some admit it. I myself deny it."
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post #183 of 404 Old 06-11-2007, 02:54 PM
 
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Originally Posted by Nuthed View Post

I don't know how you feed a speaker 120db of anything. My speakers OUTPUT dbs of sound.

What is difficult to understand is why you don't realize that speakers are capable of this very unique thing called "roll off". Say it with me now..... roll off.

This is the way a speaker that isn't capable of reproducing low bass handles those frequencies.

FWIW the very same thing happens at the other end of the spectrum as well.

All these years I have played my bedroom system with Advent Graduate bookshelf speakers, sometimes at high volume, I have never bottomed the woofers or heard any unreasonable distortion.

I just love being treated like a kindergartner by someone who doesn't understand the basics of speakers and driver performance. Speakers aren't "capable" of such a unique thing, that is their limitation. But amazingly enough, the other frequencies that the speaker is sent by the amplifier that the speaker may have a difficulty reproducing do not just disappear into some kind of ethereal space. They go through the voicecoil just like everything else. It can overheat the VC, and it can bottom out the driver very easily.

Don't think so? Don't know any better? Then feed your speakers some tones at 10-20hz and observe what happens and compare that with what you hear (or don't hear). Just because the speaker is not succeeding at reproducing the signal doesn't mean the signal isn't dangerous to the driver and hence the speaker. Indeed it can be.

But you don't have to believe me. You can easily do the test yourself. Take a driver, put it on a signal generator and feed it some deep tones that it likely is not going to reproduce successfully at any audible level, and watch what the driver does (or tries to do). Now turn up the volume a whole lot. What kinds of sounds do you hear now? This is what happens when you feed a driver a dangerous signal, which is what may occur if you try to listen near reference level (an appropriate level for watching a movie) and include LFE.

Why do you think many professional PA systems and speakers are high-passed? Because you need to play them very loud without damaging them. This is not necessarily the same thing, but listening at volume to a film soundtrack can include some very loud peaks because of the dynamic range of most DVDs, and most of these peaks will occur in scenes of high action and which may include an inordinate amount of bass which can very easily damage your speakers if you are listening at a reasonably loud volume. And no this isn't any different than listening to music with similar kinds of very deep bass at loud volumes, as anyone with listening experience or AV experience can attest to.

What ever happened to common sense? If you feed a speaker a LOT of deep bass, it is, surprisingly enough, difficult for many drivers to reproduce and it may threaten the integrity of the driver. It's why speaker abuse is not covered in the warranty of pretty much any speaker I am aware of.
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post #184 of 404 Old 06-11-2007, 05:55 PM
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Originally Posted by ChrisWiggles View Post

Oh my goodness. Suddely we all have major english comprehension problems?

Some speakers can be damaged if you feed them 120db of very deep bass. Obviously you can try to feed them that. They're not going to succeed in reproducing that kind of bass, if anything they will give you a bunch of distortion, and at worst you will very likely bottom out the drivers and you can damage the speakers in this manner.

I really do not understand why it is somehow so difficult to understand that you cannot drive SOME speakers to ridiculous volume levels with very deep bass without risking damaging them.

Apparently this is new information for some people?



First of all, where did this magical 120 dB number for a single speaker come from? That is well over "reference level" standards for any frequency, let alone deep bass. You are not talking reality here.

Next, if a speaker is down say 20 dB at 20 Hz, no one here is claiming that it will put out "full volume" at 20 Hz. No one is claiming that it will even put out any 20 Hz tone that is even useable.

Everyone here also understands that you cannot drive speakers to ridiculous volume levels (with or without very deep bass) without risking damaging them.

Np wonder you are !!!
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post #185 of 404 Old 06-11-2007, 06:56 PM
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Quote:
Originally Posted by ChrisWiggles View Post


I just love being treated like a kindergartner by someone who doesn't understand the basics of speakers and driver performance. Speakers aren't "capable" of such a unique thing, that is their limitation. But amazingly enough, the other frequencies that the speaker is sent by the amplifier that the speaker may have a difficulty reproducing do not just disappear into some kind of ethereal space. They go through the voicecoil just like everything else. It can overheat the VC, and it can bottom out the driver very easily.

Don't think so? Don't know any better? Then feed your speakers some tones at 10-20hz and observe what happens and compare that with what you hear (or don't hear). Just because the speaker is not succeeding at reproducing the signal doesn't mean the signal isn't dangerous to the driver and hence the speaker. Indeed it can be.

But you don't have to believe me. You can easily do the test yourself. Take a driver, put it on a signal generator and feed it some deep tones that it likely is not going to reproduce successfully at any audible level, and watch what the driver does (or tries to do). Now turn up the volume a whole lot. What kinds of sounds do you hear now? This is what happens when you feed a driver a dangerous signal, which is what may occur if you try to listen near reference level (an appropriate level for watching a movie) and include LFE.


You are not supposed to test any speaker that way. Not even a competent subwoofer.

Turning up the volume "a whole lot" has no meaning. Systems are calibrated these days, and a specific volume level is easy to set with the master volume control.

Also, if you claim that an appropriate level for watching a movie is near reference level, that is silly. War of the Worlds DTS version plays back at 8 dB higher in level than WOTW DD version. Which version has the correct "reference level"?



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Originally Posted by ChrisWiggles View Post


Why do you think many professional PA systems and speakers are high-passed? Because you need to play them very loud without damaging them. This is not necessarily the same thing, but listening at volume to a film soundtrack can include some very loud peaks because of the dynamic range of most DVDs, and most of these peaks will occur in scenes of high action and which may include an inordinate amount of bass which can very easily damage your speakers if you are listening at a reasonably loud volume. And no this isn't any different than listening to music with similar kinds of very deep bass at loud volumes, as anyone with listening experience or AV experience can attest to.

What ever happened to common sense? If you feed a speaker a LOT of deep bass, it is, surprisingly enough, difficult for many drivers to reproduce and it may threaten the integrity of the driver. It's why speaker abuse is not covered in the warranty of pretty much any speaker I am aware of.



Professional PA systems (and the like) are not located 10 or so feet from the listening area, and are used for large areas. They require more amplifier power and driver power handling than you need to use in a home setting. You can calculate power requirements if you know distances and speaker specifications.

http://www.myhometheater.homestead.c...alculator.html


In addition, if you have ever recorded the FR (peak levels) of music on a PC based RTA, you would know that music rolls off at around 45 Hz or so.


Your generalizations may be appropriate for a larger home theater setup (AKA high performance) being used to playback at reference level, but that is not what most people have for systems.

A system that will work just fine at a listening distance of 10 feet may not work well at all with a listening distance of 18 feet. The volume level at 1 meter for each scenario will be quite different even though each is calibrated to be equal at the listening position. If you are running on the ragged edge, then you are limited in your options.

Anyhow, speaker abuse is caused by playback at higher volume levels than the speaker can take. As you also know, testing speakers at high levels with test tones is also speaker abuse.
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post #186 of 404 Old 06-12-2007, 04:02 AM
 
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Speakers were designed to be run full-range.

Then most speaker designers either have no understanding of the term "full-range" or are truly incompetent. Or both.

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You don't really understand how a speaker works, then, do you? A speaker with a low-end F3 of 60Hz for example, doesn't disintegrate when it's sent a 20Hz signal; it just doesn't reproduce that low a frequency with any audible output, if any at all.

This isn't entirely accurate. While a speaker won't automatically fail when sent a deep bass signal (this depends on signal amplitude among other things) it will be forced to react to the signal sent to it regardless of whether it can or cannot reproduce that content. As frequency drops, impedence drops (resistance increases), the more cone movement and power required at low frequencies.

The laws of physics still apply. A sealed speaker acts like a high-pass filter below resonance. It doesn't have to respond to signals below it's resonant frequency because it acts precisely like a high pass filter. Ported speakers do not. The great majority of speakers on the market are ported not sealed.

I really don't understand where some people get this idea that just because a speaker can't physically play back deep bass frequencies well that somehow it won't respond to a high amplitude signal containing deep bass below it's passband. It goes against reality. And the reality of the situation is that just because a speaker might not generate enough output to be perceived at a given frequency does not at all mean that it won't be forced to react to said signal whether it can reproduce the content or not.

The only exception to this would be in the case of ported subwoofers with built-in limiters (or servo controlled) to prevent overexcursion, but we are talking about speakers with no high-pass filters used. I think that some people here are also forgetting that there is substantial low frequency energy in the main channels alone in many sound tracks. Spectral charts show evidence of sub-20 hz material at high amplitude (and even below in some bizarre cases) in more and more film soundtracks and that should be reason alone to be more cautious when deciding to use the 'large' setting.

Dolby wasn't kidding with their 20hz low frequency spec.

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Speakers that aren't capable of it will simply not reproduce those frequencies.



The speaker might not be able to reproduce those frequencies but that doesn't mean a thing. It doesn't mean that it won't react to the signal being sent to it. The amplifier doesn't all of a sudden ignore the signals and magically hide them from the speakers. Not only is it naive to think so, but it goes against how amplifiers and speakers actually work.

There is this thing that no one can avoid and it's called the laws of physics. A woofers pistonic motion will be increasingly non-linear as soon as it's motion exceeds it's linear excursion (VC outside the gap), and high amplitude bass at deep bass frequencies is one excellent way to achieve overexcursion. Not to mention that impedence will drop like a ton of bricks at very low frequencies especially with most AVR's. How this will affect the speakers mechanical action should be clear to anyone with even moderate understanding of mechanical systems.

Try playing back 'Master and Commander' with AVR (or pre/pro) setting to large in conjunction with the LFE at high levels. It's bad enough to try this with 'large + sub' with speakers with moderate excursion levels but in conjunction with the LFE track it's practically suicide for most speakers without a sub. This is volume dependent to a degree but I warn those who think that reference level volume is required for driver failure. It most certainly is not !

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They have a natural roll-off.



No they don't. I don't know where you got that idea from but unless you are talking about sealed designs, speakers most certainly do not have a natural roll-off. Ported designs have a 24 dB per octave drop below tuning which borders on supernatural.

Just how many people have sealed speakers for main speakers ? Few, I would imagine. Ported speakers bottom out so easily as soon as you feed signals with high amplitude, low frequency bass. And one doesn't have to play back at so called "reference levels" for this to happen either.

Just adding a few cents.

Cheers.

--Regards
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post #187 of 404 Old 06-12-2007, 04:39 AM
 
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Originally Posted by goneten View Post

Then most speaker designers either have no understanding of the term "full-range" or are truly incompetent. Or both.



This isn't entirely accurate. While a speaker won't automatically fail when sent a deep bass signal (this depends on signal amplitude among other things) it will be forced to react to the signal sent to it regardless of whether it can or cannot reproduce that content. As frequency drops, impedence drops (resistance increases), the more cone movement and power required at low frequencies.

The laws of physics still apply. A sealed speaker acts like a high-pass filter below resonance. It doesn't have to respond to signals below it's resonant frequency because it acts precisely like a high pass filter. Ported speakers do not. The great majority of speakers on the market are ported not sealed.

I really don't understand where some people get this idea that just because a speaker can't physically play back deep bass frequencies well that somehow it won't respond to a high amplitude signal containing deep bass below it's passband. It goes against reality. And the reality of the situation is that just because a speaker might not generate enough output to be perceived at a given frequency does not at all mean that it won't be forced to react to said signal whether it can reproduce the content or not.

The only exception to this would be in the case of ported subwoofers with built-in limiters (or servo controlled) to prevent overexcursion, but we are talking about speakers with no high-pass filters used. I think that some people here are also forgetting that there is substantial low frequency energy in the main channels alone in many sound tracks. Spectral charts show evidence of sub-20 hz material at high amplitude (and even below in some bizarre cases) in more and more film soundtracks and that should be reason alone to be more cautious when deciding to use the 'large' setting.

Dolby wasn't kidding with their 20hz low frequency spec.

[/b]

The speaker might not be able to reproduce those frequencies but that doesn't mean a thing. It doesn't mean that it won't react to the signal being sent to it. The amplifier doesn't all of a sudden ignore the signals and magically hide them from the speakers. Not only is it naive to think so, but it goes against how amplifiers and speakers actually work.

There is this thing that no one can avoid and it's called the laws of physics. A woofers pistonic motion will be increasingly non-linear as soon as it's motion exceeds it's linear excursion (VC outside the gap), and high amplitude bass at deep bass frequencies is one excellent way to achieve overexcursion. Not to mention that impedence will drop like a ton of bricks at very low frequencies especially with most AVR's. How this will affect the speakers mechanical action should be clear to anyone with even moderate understanding of mechanical systems.

Try playing back 'Master and Commander' with AVR (or pre/pro) setting to large in conjunction with the LFE at high levels. It's bad enough to try this with 'large + sub' with speakers with moderate excursion levels but in conjunction with the LFE track it's practically suicide for most speakers without a sub. This is volume dependent to a degree but I warn those who think that reference level volume is required for driver failure. It most certainly is not !

[/b]

No they don't. I don't know where you got that idea from but unless you are talking about sealed designs, speakers most certainly do not have a natural roll-off. Ported designs have a 24 dB per octave drop below tuning which borders on supernatural.

Just how many people have sealed speakers for main speakers ? Few, I would imagine. Ported speakers bottom out so easily as soon as you feed signals with high amplitude, low frequency bass. And one doesn't have to play back at so called "reference levels" for this to happen either.

Just adding a few cents.

Cheers.

--Regards

What kind of crap speakers do you and Wiggles use? Or do you just have such an enormous amount of power that there is no speaker capable of surviving it's fury?

As another poster noted earlier, speakers, even those pesky bookshelf type, are designed to be fed a full range signal. Period.

If you guys, unlike anyone else, want to use a bookshelf loudspeaker as a subwoofer, and feed it strictly LFE at high wattage thats your prerogative. I have to warn you though, that will definitely void the warrantee.

I run my towers, Paradigm 9V5s, full range AND I have a subwoofer. For movies I would probably be better off redirecting all bass to the sub. However I don't because I refuse to get into the setup menu every time just because I am switching from music to movie.

My speakers have a low limit of 43hz, they certainly aren't what you can call truly call "full-range". However they are designed to be fed such a signal, and they handle it quite well.
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post #188 of 404 Old 06-12-2007, 04:49 AM
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As another poster noted earlier, speakers, even those pesky bookshelf type, are designed to be fed a full range signal. Period.

IMO, that is not correct. Modern AVRs and preamps standardly have a "small" setting. If it is standard, why would it be claimed that it is intended to send full range to all speakers?
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post #189 of 404 Old 06-12-2007, 05:19 AM
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People still forget the law of conservation of energy. You have to be able to draw an energy flow diagram and all energy has to be accounted for; it doesn't just disappear. If it's not audible, it's still mechanical or thermal. If your speaker is heating up and moving without producing sound, the efficiency is plummeting, given that efficiency is defined as the 'Ratio of the total useful sound radiated from a speaker at any frequency to the electrical power applied to the voice coil.' (http://lp2cd.com/audio_terms/s/speaker_efficiency.html). I'm no expert in anything audio, but I am an electrical engineer. I can only assume that if you're losing efficiency and your transducer is suffering large energy losses, it will affect the sound.

Now, having said that, I was at my father's house last weekend. He has a 7 year old Yamaha receiver that was pretty nice in it's time, and some really tiny, cheap satellite speakers for fronts, a no-name center channel, and a tiny Aiwa subwoofer. I popped in Saving Private Ryan and changed his speaker settings to small during the beginning beach invasion scene.

I was shocked at the huge improvement in audio quality. My dad's eyes about bugged out of his head. The bass became much fuller and the entire sound stage became much more vivid and spectacular (best way I can describe it). We kept switching back and forth and were really blown away. Before reading all the posts from the very intelligent individuals on this forum, I never would have guessed that setting your speakers to "small" would increase the performance and sound quality of a home theater system. I guess the term "small" is deceiving.

On a side note, my dad was even further blown away when I discovered the installer ran his component video cables out of his cable box into the video/l/r output of his DVD player. He was watching cable on a standard RF cable! Needless to say, he was very happy when we left this weekend after viewing a true 1080i source for the first time
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post #190 of 404 Old 06-12-2007, 05:26 AM
 
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Originally Posted by Riblet View Post

IMO, that is not correct. Modern AVRs and preamps standardly have a "small" setting. If it is standard, why would it be claimed that it is intended to send full range to all speakers?

Your opinion is wrong. I have never seen a stereo only preamp or a 2 channel receiver with any speaker setup options.

That doesn't mean there aren't any though.

Yes all AVRs have bass redirection, but small bookshelf type speakers and music only systems have been around a lot longer than surround sound.

They were designed for people who didn't want or couldn't use larger speakers. And yes the trade off is less bass.
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post #191 of 404 Old 06-12-2007, 05:31 AM
 
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Originally Posted by Balforth View Post

Now, having said that, I was at my father's house last weekend. He has a 7 year old Yamaha receiver that was pretty nice in it's time, and some really tiny, cheap satellite speakers for fronts, a no-name center channel, and a tiny Aiwa subwoofer. I popped in Saving Private Ryan and changed his speaker settings to small during the beginning beach invasion scene.

I was shocked at the huge improvement in audio quality. My dad's eyes about bugged out of his head. The bass became much fuller and the entire sound stage became much more vivid and spectacular (best way I can describe it). We kept switching back and forth and were really blown away. Before reading all the posts from the very intelligent individuals on this forum, I never would have guessed that setting your speakers to "small" would increase the performance and sound quality of a home theater system. I guess the term "small" is deceiving.

That is very nice that there was an improvement in the SQ, in your case.
However I believe the OP said he had some tower speakers, not "really tiny, cheap satellite" speakers. I'm sure the OP's improvement after switching to small was much less noticeable and necessary.

BTW, how is the term "small" deceiving? If your speakers are small, you select small.

Did you possibly think it had something to do with "space" or soundstage, maybe imaging?
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post #192 of 404 Old 06-12-2007, 05:44 AM
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Blowing the mid-bass driver of any bookshelf speaker is easy to do, and I don't need test tones to do it, run any mass market rcvr in direct mode (full range) and play death metal, rap, hip-hop, trance, etc and PLAY LOUD enough and you can do it. Now for many the sound may get too uncomfortable (due to sheer volume or, more often, distortion) brfore that point, but usually this occurs well before accepted "referance" levels. Now I am not advocating constant listening at performance levels, but I do like using more power so that I can approach these levels, when moved by the music, without as much distortion.
I have sat in rooms and been to clubs where the music didn't seem loud as it was very "clean" (relatively distortion free), but when you went to try and talk over it, there was no chance.
Taking the weight of responsibility for very low frequencies off of the speakers and amps is a good idea if you like to listen loud (or in a large space) and if you can decently blend the sub in at that point so music remains defined and articulate and blends with the mains.

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post #193 of 404 Old 06-12-2007, 06:00 AM
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That is very nice that there was an improvement in the SQ, in your case.
However I believe the OP said he had some tower speakers, not "really tiny, cheap satellite" speakers. I'm sure the OP's improvement after switching to small was much less noticeable and necessary.

BTW, how is the term "small" deceiving? If your speakers are small, you select small.

Did you possibly think it had something to do with "space" or soundstage, maybe imaging?

I made a post earlier in this thread that said if he has a REALLY crappy subwoofer (even if he didn't) and switched to large and it sounded better, then leave them at large! All the technical details and specifications don't mean squat if it doesn't sound better to YOU! I didn't mean for the story about my dad to be the definitive answer on how all systems should be set. I was just excited about the improvement that we heard on his system.

And "small" is deceiving because what it really means is "crossed-over". In relation to our discussion, this happens to be a high-pass filter, and in many systems, this high pass filter can be set very low. You could have huge towering full-range speakers and you still might decide to cross them over at some frequency and send all lower freq. to your sub to let your sub amp bear that cross. In my dad's case, his little speakers which would otherwise just "lose" the low freq. info that they couldn't reproduce really came to life when the amp was only trying to send it the frequencies it was capable of handling

Or maybe amplifier headroom isn't an issue; maybe your sub just reproduces those frequencies much better than your full range mains. It really doesn't have anything to do with whether or not your speakers are physically big or small. It has to do with how you wish to divide and direct the different audible frequencies of your system.

In other words, just because you're high-pass filtering your mains doesn't mean they are small in size. Your high pass filter could be set to 50Hz. Hell, your high pass filter could be set to 10Hz. I'm not sure if COTS receivers are capable of these frequency cut-offs, but it would be trivial to implement and could still be implemented at any point before the actual speaker, if not in the receiver.
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post #194 of 404 Old 06-12-2007, 06:12 AM
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Originally Posted by goneten View Post

Then most speaker designers either have no understanding of the term "full-range" or are truly incompetent. Or both.


--Regards


Speaker designers do not say that their speakers will play back flat for the full audio range, not has anyone else said that.

Speakers can be sent full range signal without self destructing, and that is what is being discussed (at this point in time). Examples of this would be nearly every television speaker that has ever been made, auto radio speakers, boom box speakers, etc.

How about headphones? They are about as small as you can get!



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The speaker might not be able to reproduce those frequencies but that doesn't mean a thing. It doesn't mean that it won't react to the signal being sent to it. The amplifier doesn't all of a sudden ignore the signals and magically hide them from the speakers. Not only is it naive to think so, but it goes against how amplifiers and speakers actually work.



Speaker sensitivity drops when you are out of the speakers passband. You put in voltage from the amplifier, and you get out driver movement and heat in voice coil. Out of the passband, you get less driver movement and more heat in voice coil.

We are talking about driver movement!




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Try playing back 'Master and Commander' with AVR (or pre/pro) setting to large in conjunction with the LFE at high levels. It's bad enough to try this with 'large + sub' with speakers with moderate excursion levels but in conjunction with the LFE track it's practically suicide for most speakers without a sub. This is volume dependent to a degree but I warn those who think that reference level volume is required for driver failure. It most certainly is not !



I have done that many times. War of the Worlds is a good one also. However, my ears can not take full "reference level" (120 dB theoretical 5.1 total volume). My system can not produce those levels either!

Just how much extra signal level do you think is sent to your mains speakers via your receiver or pre/pro when LFE and redirected bass is sent to them? From what you are writing, you don't seem to know the answer.





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Just how many people have sealed speakers for main speakers ? Few, I would imagine. Ported speakers bottom out so easily as soon as you feed signals with high amplitude, low frequency bass. And one doesn't have to play back at so called "reference levels" for this to happen either.



I do!

Ported sub however!
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post #195 of 404 Old 06-12-2007, 06:27 AM
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Originally Posted by Schadenfreude View Post

Blowing the mid-bass driver of any bookshelf speaker is easy to do, and I don't need test tones to do it, run any mass market rcvr in direct mode (full range) and play death metal, rap, hip-hop, trance, etc and PLAY LOUD enough and you can do it. Now for many the sound may get too uncomfortable (due to sheer volume or, more often, distortion) brfore that point, but usually this occurs well before accepted "referance" levels. Now I am not advocating constant listening at performance levels, but I do like using more power so that I can approach these levels, when moved by the music, without as much distortion.


Music (AKA CD's. etc) are not a calibrated medium, so your reference to music being played back below "reference level" has no meaning whatever. There is no "reference level", just a volume level.




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Originally Posted by Schadenfreude View Post

Taking the weight of responsibility for very low frequencies off of the speakers and amps is a good idea if you like to listen loud (or in a large space) and if you can decently blend the sub in at that point so music remains defined and articulate and blends with the mains.


Sure, but what does "loud" mean? One man's "loud" is another man's "turn up the volume" is another man's "are you deaf"!

I have assumed that this thread was about normal home systems. High performance system system used in large rooms at "loud" volume levels have high performance requirements in speaker output capabilities as well an in amplification.
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post #196 of 404 Old 06-12-2007, 06:41 AM
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Music (AKA CD's. etc) are not a calibrated medium, so your reference to music being played back below "reference level" has no meaning whatever. There is no "reference level", just a volume level.

Measured listening volume in the middle of the live venue in which it was recorded ...easier if it's music that's acoustic in nature.

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I have assumed that this thread was about normal home systems.

Me too.
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High performance system system used in large rooms at "loud" volume levels have high performance requirements in speaker output capabilities as well an in amplification.

Yeah, that's the point, but even in normal rooms with higher quality gear, the limits can often be found rather easily

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Maybe someday in the future we will be able to quantify perceived Sound Quality .
(But not today....)

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post #197 of 404 Old 06-12-2007, 06:42 AM
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Originally Posted by Riblet View Post

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As another poster noted earlier, speakers, even those pesky bookshelf type, are designed to be fed a full range signal. Period.

IMO, that is not correct. Modern AVRs and preamps standardly have a "small" setting. If it is standard, why would it be claimed that it is intended to send full range to all speakers?

Your opinion is wrong. I have never seen a stereo only preamp or a 2 channel receiver with any speaker setup options.

That doesn't mean there aren't any though.

Yes all AVRs have bass redirection, but small bookshelf type speakers and music only systems have been around a lot longer than surround sound.

They were designed for people who didn't want or couldn't use larger speakers. And yes the trade off is less bass.

I am a little frustrated here. Why are you bringing a two-channel system into a discussion of 5.1 and 7.1 type systems? It is true, indisputable fact, that a standard feature is bass control, often via a "small" setting for speakers. If you instead want to talk about 2-channel systems, well... the entire thread is moot. There is no channeling of low frequency content to the sub since there isn't any sub channel.

"Pesky bookshelf type" speakers are designed to reproduce a limited range of sound. They are limited in reproducing low frequencies. If they sound better with a less-than-full-range signal being fed into them, then it is my opinion that they are not designed to be fed a full range signal. The only question is what signal entering the speaker sounds best? I have personally never heard a small speaker sound better with a full signal versus with a high-pass crossover set to a proper frequency.
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post #198 of 404 Old 06-12-2007, 06:54 AM
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Originally Posted by Balforth View Post

People still forget the law of conservation of energy. You have to be able to draw an energy flow diagram and all energy has to be accounted for; it doesn't just disappear. If it's not audible, it's still mechanical or thermal. If your speaker is heating up and moving without producing sound, the efficiency is plummeting, given that efficiency is defined as the 'Ratio of the total useful sound radiated from a speaker at any frequency to the electrical power applied to the voice coil.' (http://lp2cd.com/audio_terms/s/speaker_efficiency.html). I'm no expert in anything audio, but I am an electrical engineer. I can only assume that if you're losing efficiency and your transducer is suffering large energy losses, it will affect the sound.



No one has said otherwise. You can't get a 20 Hz tone (at useable levels) out of a speaker that is not capable of playing that signal. Obviously, that affects sound reproduction.

The issue is, will that destroy a speaker? Your father ran his small speakers as large for 7 years. Were they ever destroyed?







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Now, having said that, I was at my father's house last weekend. He has a 7 year old Yamaha receiver that was pretty nice in it's time, and some really tiny, cheap satellite speakers for fronts, a no-name center channel, and a tiny Aiwa subwoofer. I popped in Saving Private Ryan and changed his speaker settings to small during the beginning beach invasion scene.

I was shocked at the huge improvement in audio quality. My dad's eyes about bugged out of his head. The bass became much fuller and the entire sound stage became much more vivid and spectacular (best way I can describe it). We kept switching back and forth and were really blown away. Before reading all the posts from the very intelligent individuals on this forum, I never would have guessed that setting your speakers to "small" would increase the performance and sound quality of a home theater system. I guess the term "small" is deceiving.

On a side note, my dad was even further blown away when I discovered the installer ran his component video cables out of his cable box into the video/l/r output of his DVD player. He was watching cable on a standard RF cable! Needless to say, he was very happy when we left this weekend after viewing a true 1080i source for the first time



Well, who setup your fathers receiver in the first place? He has a subwoofer and small speakers, so why would you be "shocked" at the improvement in sound quality when you setup the system properly? I am shocked that it took 7 years to be setup right.

That is just as bad as what the OP did with his system.

The OP had larger main speakers and no subwoofer, but he told his system that he did have a subwoofer and small speakers. The result was no LFE and no bass redirection of small speaker bass to the main speakers because he told the receiver to send al that bass to the subwoofer (that did not exist).

Your father's system obviously has small speakers and a subwoofer. Setting the speakers to large and subwoofer to ON means that only LFE was being set to the subwoofer, and bass below the small speakers frequency capabilities were not being reproduced.




Like Silvy said, people should just follow the directions in the instruction manual. Makes you wonder how many systems are setup properly regardless of speaker size!
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post #199 of 404 Old 06-12-2007, 07:25 AM
 
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Originally Posted by Riblet View Post

I am a little frustrated here. Why are you bringing a two-channel system into a discussion of 5.1 and 7.1 type systems?

Because you said that bookshelf speakers aren't designed to accept full range signals....I provided an example that refutes your claim.


[/quote]"Pesky bookshelf type" speakers are designed to reproduce a limited range of sound. They are limited in reproducing low frequencies. If they sound better with a less-than-full-range signal being fed into them, then it is my opinion that they are not designed to be fed a full range signal.[/quote]

See the above post, #194, about TV speakers and the like.
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post #200 of 404 Old 06-12-2007, 07:47 AM
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Originally Posted by J_Palmer_Cass View Post

No one has said otherwise. You can't get a 20 Hz tone (at useable levels) out of a speaker that is not capable of playing that signal. Obviously, that affects sound reproduction.

The issue is, will that destroy a speaker? Your father ran his small speakers as large for 7 years. Were they ever destroyed?

There are many places in this thread where people have said that a speaker will only reproduce what it can and the rest is just lost. While this is technically correct, those losses are a detrement to the system and should be avoided if at all possible. It seems to me the concept trying to be conveyed is that it's perfectly normal to send a speaker energy that it cannot physically convert into sound and there are no ill effects or consequences from it. If I misinterpreted this I apologize, but it really seems like people are trying to preach this gospel. And no, my dad's speakers are just fine. My parents are old and aren't into cranking up the volume. I could only imagine that if these little baby speakers were cranked, they would blow. I've blown many speakers in my life. I've blown car speakers using the factory head-unit.

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Originally Posted by J_Palmer_Cass View Post

Well, who setup your fathers receiver in the first place? He has a subwoofer and small speakers, so why would you be "shocked" at the improvement in sound quality when you setup the system properly? I am shocked that it took 7 years to be setup right.

That is just as bad as what the OP did with his system.

I set it up, and I'm shocked because I've never even knew receivers were capable of setting speakers to large and small. I'm not an audiophile and I'm new to all of this. I've been reading about it for quite a while, but I've never been able to implement it. It was new knowledge to me, and it came as a very pleasing "shock". I'm not sure that my expression of happiness over discovering the proper way to set up a home theater system warrant your sarcasm.

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Originally Posted by J_Palmer_Cass View Post

The OP had larger main speakers and no subwoofer, but he told his system that he did have a subwoofer and small speakers. The result was no LFE and no bass redirection of small speaker bass to the main speakers because he told the receiver to send al that bass to the subwoofer (that did not exist).

Your father's system obviously has small speakers and a subwoofer. Setting the speakers to large and subwoofer to ON means that only LFE was being set to the subwoofer, and bass below the small speakers frequency capabilities were not being reproduced.

Like Silvy said, people should just follow the directions in the instruction manual. Makes you wonder how many systems are setup properly regardless of speaker size!

But he also has a small subwoofer. How do I set the subwoofer to "small"? What would that possibly even mean if a receiver had the option to set a subwoofer to "small"? It could mean a reduction in gain; it could mean a high-pass crossover; it could mean a band-pass crossover; it could mean a lot of things.

"large" and "small" are only names that appear on your receivers display. Technically what's happening is a crossover being applied to the signal and information being re-routed. I think it seems really nice to be able to be in control of these settings and to limit the input of each speaker to a reasonable frequency range which the speaker was originally designed to work with. Just looking at a speaker cabinet and saying "big" doesn't seem like a good formula for determining the overall best configuration of these parameters.

I'm not convinced that if his speakers were "large" in size, the entire system would absolutely sound better if the receiver set the speakers to "large". I think that could be judged on a per-system basis. If his sub outperforms his "large" speakers with low frequencies, it may sound better if he high-pass filters his "large" speakers and sends the cut-off info to the sub. If his amp is under too much strain from amplifying full-range information, it may sound better if his "large" main speakers are crossedover and the sub's amp handles the low freq. info.

To each his own I like to be slightly more technical and in control. I'll try to not be shocked in the future as I continue to gain new knowledge and really have fun with this hobby! (ps my system is still in boxes waiting for my new house to be finished)
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Originally Posted by J_Palmer_Cass View Post

First of all, where did this magical 120 dB number for a single speaker come from? That is well over "reference level" standards for any frequency, let alone deep bass. You are not talking reality here.

Next, if a speaker is down say 20 dB at 20 Hz, no one here is claiming that it will put out "full volume" at 20 Hz. No one is claiming that it will even put out any 20 Hz tone that is even useable.

Everyone here also understands that you cannot drive speakers to ridiculous volume levels (with or without very deep bass) without risking damaging them.

Np wonder you are !!!

You have been on my ignore list for a very long time, but in case anyone else is reading, I will only address the 120db figure, which is the potential bass peaks that will be contained in the main channels in addition to the LFE when listening to DD properly calibrated at reference level without a subwoofer and with the LFE re-routed to the main channels.

As I have already referenced:
http://www.hometheaterhifi.com/volum...pril-2000.html
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What kind of crap speakers do you and Wiggles use? Or do you just have such an enormous amount of power that there is no speaker capable of surviving it's fury?

If you really are curious, which I am sure you're not since you don't understand the basics of speaker design and function, I use Dynaudio Contours.

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As another poster noted earlier, speakers, even those pesky bookshelf type, are designed to be fed a full range signal. Period.

Of course. That does not mean that they are not capable of being damaged by a high amplitude low frequency signal. The two things are not mutually exclusive.

Why you are arguing this is beyond me. You 1) do not have the experience to know one way or the other and 2) have had the basics of speaker design explained to you by people much more knowledgeable than yourself, yet despite this you continue to fein ignorance and forward an erroneous position.
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post #203 of 404 Old 06-12-2007, 12:21 PM
 
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Because you said that bookshelf speakers aren't designed to accept full range signals....I provided an example that refutes your claim.

How many times do I and others have to say this. Absolutely they can handle reasonable full range signals with no problem and no threat to the speakers. However, if you increase the power with which you are feeding the speakers, you will eventually reach a point where you are overdriving the speakers and you can damage them. This is much easier to do if you feed such a speaker, especially a ported speaker, very low frequencies at high amplitude.

Returning to my first post in this thread, we were discussing home theater soundtracks, namely Dolby Digital soundtracks which include an LFE, and many such tracks include an inordinate amount of very low bass, the kind which you are less likely to find in most music (but which you can find in some music and can also be dangerous to a less-than-capable system if played at high volume.

As I have said before, if you listen to a film soundtrack at an appropriate volume even 10-15db below reference, you can still have very very significant bass peaks especially from the LFE, and this may threaten the integrity of some speakers.

None of this is controversial, it's basic physics, something that it appears several of you are quite ignorant of, which is fine on its own but don't go arguing about it if you don't know what you're talking about.

If you take any of those pesky and pathetic TV speakers you mention and feed it the kind of full range signal at volume somewhere near reference level, I'm quite sure you'd be bottoming out such a tiny driver like crazy. Why do I know this? Because I've done this many times before in many different audio systems, from many different signal sources, and on speakers and drivers FAR more capable of handling these kinds of signals than relatively small bookshelf speakers that seem to be the topic of discussion here.
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Sure its possible with *enough* power to bottom out the drivers, but in most cases, you'd still be more likely to hit clipping in the majority of receivers, due to the natural rolloff of most drivers as well as any possible protection built into the XO.

I think the problem that you are having is this:
"As I have said before, if you listen to a film soundtrack at an appropriate volume even 10-15db below reference, you can still have very very significant bass peaks especially from the LFE, and this may threaten the integrity of some speakers."

Yes, if you tried to reproduce a 100dB 20Hz tone from a pair of small speakers, you wouldn't get a heck of a lot except a dead pair of speakers. However, just because you set your receiver to -10dB doesn't mean the speakers are going to produce each frequency at 100dB. The speakers output at 20Hz may only be 70dB, which is a factor of 1024 less in terms of acoustical power output, and won't damage it. See the problem?
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Originally Posted by Stefano-M View Post

Sure its possible with *enough* power to bottom out the drivers, but in most cases, you'd still be more likely to hit clipping in the majority of receivers, due to the natural rolloff of most drivers as well as any possible protection built into the XO.

I think the problem that you are having is this:
"As I have said before, if you listen to a film soundtrack at an appropriate volume even 10-15db below reference, you can still have very very significant bass peaks especially from the LFE, and this may threaten the integrity of some speakers."

Yes, if you tried to reproduce a 100dB 20Hz tone from a pair of small speakers, you wouldn't get a heck of a lot except a dead pair of speakers. However, just because you set your receiver to -10dB doesn't mean the speakers are going to produce each frequency at 100dB. The speakers output at 20Hz may only be 70dB, which is a factor of 1024 less in terms of acoustical power output, and won't damage it. See the problem?

Yes I do see the problem. The problem is in your thinking that because a speaker is not producing audible sound that therefore it cannot be damaged.

Have you ever feed a speaker a large amount of DC? DC sounds like, well, nothing. But it sure as heck can short a VC in an instant.

An average small 2-way bookshelf speaker wouldn't even be outputting any recognizable tone of 70db at 20hz, it probably would not even be measurable, let alone audible. But that doesn't mean it's not dangerous to the speaker.

We're not concerned with acoustical power output at all. We're concerned with the electical signal being fed to the VC and also how the driver reacts to that signal (because there is also physical damage possible in addition to thermal damage). Whether you hear anything at all is immaterial, a point which several people in this thread fail to understand, despite numerous explanations.
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post #206 of 404 Old 06-12-2007, 02:16 PM
 
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Originally Posted by ChrisWiggles View Post

Yes I do see the problem. The problem is in your thinking that because a speaker is not producing audible sound that therefore it cannot be damaged.

Not quite the problem...

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Originally Posted by ChrisWiggles View Post

An average small 2-way bookshelf speaker wouldn't even be outputting any recognizable tone of 70db at 20hz, it probably would not even be measurable, let alone audible. But that doesn't mean it's not dangerous to the speaker.

Have you seen an FR chart of a bookshelf speaker? Sure, its mostly distortion, but it has output at 20Hz unless otherwise limited.


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Originally Posted by ChrisWiggles View Post

We're not concerned with acoustical power output at all.

No, were concerned with the motion of the cone mostly. If it hits its end stop, then you need to turn it down. However, reducing acoustical output significantly reduces cone travel. As far as overheating the voice coil, its doable, but like I said, you'd be more likely to hit clipping first in the majority of receivers.


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Originally Posted by ChrisWiggles View Post

We're concerned with the electical signal being fed to the VC and also how the driver reacts to that signal (because there is also physical damage possible in addition to thermal damage).

Alright, lets look at the electrical signal... To make it easier, lets assume we have a speaker with a flat impedance curve of 8 ohms. What is the difference between the electrical signal it receives for 20Hz versus 100Hz when the receiver is set to -10dB?
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post #207 of 404 Old 06-12-2007, 02:22 PM
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you'd be more likely to hit clipping first in the majority of receivers.

THE MAJORITY OF RECEIVERS ARE MASS MARKET AND CURRENT LIMITING .

I think it would be generally more useful if everyone new to these forums is reminded that they are constantly being marketed to and pitched by people who post their affiliations and many others who do not. This is all part of marketing and advertising and you, the consumer, are the targets.
Noth...
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post #208 of 404 Old 06-12-2007, 02:25 PM
 
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THE MAJORITY OF RECEIVERS ARE MASS MARKET AND CURRENT LIMITING .


Well if they limit their output to 40 watts or so at 8 ohms without clipping, I still don't see it overheating the voice coils of too many speakers of decent quality speakers, nor do I see how they'll drive a decent quality bookshelf into overexcursion.
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post #209 of 404 Old 06-12-2007, 02:30 PM
 
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Originally Posted by Stefano-M View Post

Not quite the problem...

Have you seen an FR chart of a bookshelf speaker? Sure, its mostly distortion, but it has output at 20Hz unless otherwise limited.

Yes. And as I have said repeatedly, that is completely beside the issue. It doesn't matter what the speaker is outputting. It matters what signal the speaker is seeing from the amplifier. As I just explained, the effective acoustical output at 20hz could be 0db, but that doesn't mean it's not dangerous. Why are you so focused on the acoustical output? It's completely beside the point, as I say over and over, and as others have explained.

Quote:


No, were concerned with the motion of the cone mostly. If it hits its end stop, then you need to turn it down. However, reducing acoustical output significantly reduces cone travel. As far as overheating the voice coil, its doable, but like I said, you'd be more likely to hit clipping first in the majority of receivers.

The "cone?" Please. You must be referring to the voice coil and/or the voice coil former. They are quite different than the cone. You are extremely unlikely to damage the cone at all unless you stab at it with a knife or the VC catches on fire or something.

But far be it from me to explain the very basics of speakers and transducers to you...

Quote:


Alright, lets look at the electrical signal... To make it easier, lets assume we have a speaker with a flat impedance curve of 8 ohms. What is the difference between the electrical signal it receives for 20Hz versus 100Hz when the receiver is set to -10dB?

Okay, let's examine that question and observe that it's a completely meaningless question without any parameters.

Let's examine another difference: one poster doesn't know the most basic speaker terminology, and doesn't understand how a speaker and speaker driver operate either alone or in combination.

Several other posters with intimate knowledge of basics physics explain the workings of a speaker and speaker drivers.

Who would you believe?

You want to keep going in circles? Or do you want to go to your local library and check out a book or two about speaker and driver design? Or maybe you could just read gonoten's post earlier in the thread:
http://www.avsforum.com/avs-vb/showt...&#post10767335

I've already suggested that you try this yourself. Hook up a driver to a signal generator and play around. It's not that difficult to see exactly what I and others have described. Don't have a signal generator? Do some google searches on test tones or test CDs, and play some low frequency tones through some spare speaker drivers and observe what occurs.

The basic laws of physics are, surprisingly enough, fairly established laws.
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post #210 of 404 Old 06-12-2007, 02:34 PM
 
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Originally Posted by Stefano-M View Post

Well if they limit their output to 40 watts or so at 8 ohms without clipping, I still don't see it overheating the voice coils of too many speakers of decent quality speakers, nor do I see how they'll drive a decent quality bookshelf into overexcursion.

But you've never tried have you? And you wouldn't have any idea, you just have an opinion (an uninformed one, given that you don't understand the basic components of a speaker) based on limited experience. Yet in the presence of facts contrary to your unsupported 'idea' of what you 'see' to be the case, you just reject such facts. Why? Because the "well, drrr, I don't see how it could by george..." logic.

Wonderful... :/
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