Art Welter wrote on Tue, 06 January 2009 04:12 |
Elliot,
The scenario you just described:
“Many tend to roll off essential frequencies then, increase the volume to make up the loss in SPL of the missing frequencies to make it sound more balanced. By doing so the xmax is used up even more at the higher frequencies, and the user ends up exceeding the driver's mechanical limits.”
is far more likely to result in thermal rather than mechanical failure.
In over thirty years of looking at failures,(and making a few) I have not seen a mechanical failure that could be attributed to setting a hi pass too high.
Give me one real world example (of the “many”) of a sub high passed too high, where the cone, spider, or surround ripped or the voice coil was flattened rather than burnt.
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Art,
The examples I’ve seen or should I say heard are:
The voice coil bouncing up and down with the cone while the spider is unattached. It sounds like chains banging against a metal shutter.
The voice coil jumps out of its magnetic gap and dislodged itself. Which in turn, prevents coil from re-entering the magnetic gap.
The cone tears in an angular fashion, which started from the voice coil and, proceeds to rip all the way up to the surround.
Please bear in mind that driver failures vary based on music material involved during such accidents. When a driver doesn't have enough xmax, you have enough power to exceed the mechanical limits while having the subs high-passed @ 50 Hertz. This is due to having 60, 70, and, 80 Hertz offering a strong enough signal to move the cone. So the only thing needed is a strong dynamic signal with a powerful amplifier to reinforce the material and you can exceed the driver’s limit. I’ve witnessed woofers “popping” away and the user has no idea why the drivers are making that sound. It’s an unfamiliar sound, which many never heard before.
Since we are talking pre-recorded material where 40 – 30 Hertz is common, when a track has all it’s information lying within 40 – 30 Hz region, that DJ is going to raise the fader until he/she gets the sound they are accustomed to hearing.
If we were discussing live music, it would be different story for it’s rare to have 98% of your bass residing from 50 Hertz – down.
Driver failure always boils down to not having enough speakers for the job. Some resort to feeding their speakers more power and rolling off the lower notes as a means of protection, which solves the problem. However there are some that find such methods useless. It did not work and, the only alternative is to buy more speakers. Those who fall into that category tend to be DJs playing tracks that offer all its energy below 50 Hertz. So as far as they are concern, you turned down their bass and, they will raise the fader to get it back.
Best Regards,