Can a sub be "a bit" blown? - diyAudio
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Old 19th October 2005, 12:52 PM   #1
bigwill is offline bigwill  United Kingdom
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Question Can a sub be "a bit" blown?

I was driving my subs pretty hard today and I accidently turned up the volume too high for a short period of time, and I was worried that I may have caused some damage to them.

I don't know if they bottomed out because the time they were loud was so short but it still made me wonder if they got damaged. They're not rubbing and sound fine, I'm just really paranoid about blowing up my drivers...

I then proceeded to play some test tones to see how loud my subs would go but I chickened out before turning them too high for fear of blowing them so I never saw the speakers bottom out and I couldn't hear the amp clipping. Saying that, I think I caused the amp to clip slightly at one point when playing a 25Hz tone. As I'm powering my subs with a 40w 25 year old Trio (now kenwood) amp, clipping is a concern.

Is it possible for a driver to be "slightly" blown as a result of all this "abuse", so it wont sound as good as it did but still works? I've got the whole OCD thing going on about damaging the sound quality of my speakers


Edit: ARGH, I accidently did it again. I'm running my hifi from a PC and this media player makes it entirely too easy to accidently turn the volume right up if you accidently jerk the mouse. Unfortunately it scales up the waveform digitally and this time it definately clipped and sent TONS of distorted **** to my speakers and now I'm really worried (but they still seem to work fine). I'm going to build some proper equipment now, I'm sick of this stupid setup. I need a preamp.
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Old 19th October 2005, 01:16 PM   #2
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Need more info to be sure. What is the box type and volume, and vent frequency if present? What are the drive units?

As a very rough stab they are OK as bottoming out sounds quite nasty. And a 40W amp isn't likey to do much for a short while if the sub is rated as subs are these days.
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Old 19th October 2005, 01:19 PM   #3
bigwill is offline bigwill  United Kingdom
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It's a TL tuned to about 25Hz, and the drive units are cheapo MCM ones (despite this they seem to work quite well). The problem is they're only rated at 70w RMS. I'm worried about my tweeters too, now I'm such an idiot.
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Old 19th October 2005, 03:10 PM   #4
simon5 is offline simon5  Canada
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LOL, don't worry too much my friend.

When clipping, the amplifier will send about 80W RMS. The subwoofer driver voicecoil can easily take that, especially for short periods of time.

If you don't bottom the driver too often, you won't break anything.

For the tweeter, just listen to it and you'll know if it's damaged. If it's protected by a proper 2nd order x-over or higher order, I wouldn't worry much about it.

To break a subwoofer, you need serious clipping, at least two times the RMS rating of the driver for at least a dozen of seconds. I mean, the copper need vaporize, you need serious power to do that. To break the suspension, foam is kind of strong, you'll need to abuse it alot under tuning to definitely break it.
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Old 19th October 2005, 03:31 PM   #5
bigwill is offline bigwill  United Kingdom
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Well, the tweeter's on a 1st order crossover, but the time I was clipping was only about 1 second maximum. I don't drive my equipment hard usually so thats why its such a big worry. I'll have a listen later and see how it sounds.


I'm sure the sub could handle 80 or even 100 watts for a second As for the suspension, it's made of rubber so it's strong enough
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Old 19th October 2005, 03:43 PM   #6
simon5 is offline simon5  Canada
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You see, no worry about the subwoofer.

Check the tweeter, 1st order is dangerous when you clip the amp, but it was not for a long time, so I guess it'll be ok.
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Old 19th October 2005, 04:56 PM   #7
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As well a surround damage, the spider is usually done at the same time. Also the voicecoil can smash into the backplate on cheap speakers and even some not cheap speakers.

But unless you heard major bad sounds when you cranked it, it will all be fine.
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Old 19th October 2005, 07:06 PM   #8
bigwill is offline bigwill  United Kingdom
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I'm still kinda worried
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Old 19th October 2005, 07:13 PM   #9
ruerose is offline ruerose  Canada
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listen to some piano music, it should sound distorded pretty easily.

It's what I use to test blown tweeters
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Old 20th October 2005, 12:10 AM   #10
simon5 is offline simon5  Canada
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Talking about blowing tweeters, a girl I know just blew the tweeter in 4 Infinity Primus 150 satellites hehe!

She was testing her new Creative X-Fi with udial.wav hehe!

The udial test is lots of HF to test the bad IMD in the HF range of the older Creative soundcards. The new X-Fi have improved resampling so the card pass the udial.wav test.

These speakers got a 2nd order x-over at 3.3 kHz. She heard rattling when testing, so overexcursion with a 2nd order x-over that high? Is that possible? Her amp is a Pioneer (100W/ch) and was at -23 dB so I'd guess around 1W RMS per channel.

I wonder what happened, do you guys have any idea? It's impossible to blow tweeters with 1W RMS IMHO...
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