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If you were to put - 5W speaker to 10-15W amplifier which - bass or treble will most likely damage it first? From what I've heard and learned - boosted bass makes speaker move back and forth and if that moving energy is too big for the speaker to handle it may rip. On the other side, boosted high frequencies generate more heat in the tweeter and it may overheat*.

One more interesting thing I found, is that it is generally better to put a 5W speaker to 10W amp instead of 5W speaker with 5W amplifier which is starting to clip because square sound waveforms (distortions) put much stress into a speaker and it starts generating heat if the clipping is too much. It may even catch on fire! While 10 clean watts give 'natural frequencies which don't put as much stress (peaks) and is easier on the speaker even though it's louder.

I think this is an interesting topic to know about.

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  • \$\begingroup\$ Cup moves with high-mids and trebles, cone moves with bass and low-mids. So the basses would damage most IMO. \$\endgroup\$ – Rohat Kılıç Nov 4 '16 at 14:00
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    \$\begingroup\$ Well, I prefer having my speakers clipping because the amp saturates rather than having them clipping because the amp is too powerful and they reach their maximum deflection... \$\endgroup\$ – dim Nov 4 '16 at 14:07
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    \$\begingroup\$ "... it is generally better to put a 5W speaker to 10W amp instead of 5W speaker with 5W amplifier ..." - False. \$\endgroup\$ – marcelm Nov 4 '16 at 14:28
  • \$\begingroup\$ Perhaps. There is various opinions on this subject from what I found \$\endgroup\$ – Giedrius Nov 4 '16 at 15:10
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    \$\begingroup\$ Clipping is killing for your tweeters. When clipping, excessive amplitudes in high frequencies, much larger in amplitude than for normal sounds. Therefore the maximum rating is much easier exceeded than you might expect. \$\endgroup\$ – jippie Nov 4 '16 at 17:27
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As pointed out in other response, it is heat that usually causes speaker failure. I recommend this article for some additional details on physical failure mechanisms: https://sound-au.com/articles/speaker-failure.html

There are a few other details worth mentioning, since your original question asked about what frequencies are more likely to cause failure.

Low frequencies (relative to the driver in question) can often cause failure because, for a given sound power output, lower frequencies require greater cone excursion. If excursion becomes so great that the voice coil actually leaves the magnetic gap, a magnetic short is formed and lots of heat is produced. Drivers usually have a specified maximum excursion, called Xmax. Speakers designed to produce lower frequencies generally have much larger Xmax values so they can deliver sound power at low frequencies. At any rate, care must be taken to insure that the driver is not driven in such a way that the cone excursion exceeds Xmax. This can be achieved by limiting the total power delivered to the driver and/or by applying a high-pass filter to prevent low frequencies with higher associated excursions from being delivered to the driver.

For different reasons, high frequencies (relative to the driver in question) can also cause failure through a mechanism known as breakup. Basically, standing waves can develop on the cone itself. Because cones are not designed with the resulting stress in mind, this can cause the cone itself fracture.

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Speaker damage (not destruction) is very often caused by heat. The gap between the moving voice coil and the fixed magnet assembly is very small. Any distortion of the cylindrical voice coil can cause rubbing. The effect is audible, but the speaker still "works". Carefully pushing the cone (with even pressure) of a disconnected speaker, you can hear or feel the scraping sound. That's a damaged speaker.
Heat can also cause the voice-coil windings to de-laminate from the cylindrical cone they're wound on. Again, you can suffer scraping in the small gap. Of course, enough heat breaks the wire, and the speaker goes from a few ohms to infinite ohms.
Some of those low-frequency speakers can bottom-out, where some part of the voice coil smashes against the fixed magnet assembly. The voice-coil cap may pop off, the attachment point between cone and voice coil may rip, or the voice coil distorts and, as above, scrapes in the gap. The spider (the corrugated mesh that keeps the voice coil centered) might also come adrift. These damages are usually audible, but the speaker still produces sound. Not a usual failure mode for tweeters. Can be caused by an unexpected loud blast or turn-on transient. This one can happen without the usual heat-related damage.
Another failure mode not heat-related is failure of the flexible surround that attaches the cone to the basket. These are made of light materials, and take a lot of flexing, especially in bass speakers. Heat, sunlight, chemical decomposition can stiffen the surround material causing cracking, or detach at the glue joint.

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  • \$\begingroup\$ So to put it shortly.. speaker damage is more often causes by high frequencies and tweeter overheating? And rather excessive bass boost instead of treble is safer for the speaker? \$\endgroup\$ – Giedrius Nov 4 '16 at 15:27
  • \$\begingroup\$ @Giedrius, I didn't intend to give that impression. Have seen both tweeter & bass damage, but more bass damage on the whole. Much music contains relatively more bass than treble, and pushes more power into bass drivers, especially when bass-boost is employed. Hopefully, a builder matches power capability of both bass & treble drivers. Power-handling specs of drivers are often misleading - you don't know if they're referring to rms, p-p, or acoustical watts. \$\endgroup\$ – glen_geek Nov 4 '16 at 16:03
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The most efficient frequency is at bass resonance and also lower frequencies have larger cone displacement. So the frequency that exceeds the travel where the braided wire breaks is the answer. Unless you melted the windings then it is not freq. but Pd....

In the old days we only used $25 Philips 12" speakers with no crossover and put 1W for normal listening and 100W for really loud in a tuned cabinet ( e.g. labyrinth reflex)

Think big. As Robin Williams once said " You can't make butter out of milk whipping it with a toothpick"

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  • \$\begingroup\$ What if you just need a tiny bit of butter? \$\endgroup\$ – DKNguyen Aug 1 '19 at 22:37

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