Blowing a Full Range Speaker

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Hello,

I'm using a "full range speaker" that does not respond well under 100-200hz. It is 40watt rated and I am using a 30watt amplifier. I have noticed that it is starting to sound a bit distorted like its going to blow.

I think that its because of the low frequencies its receiving but unable to represent.

2 questions

1. Does that blow a speaker?
2. I can build a High pass filter for it but what are the right components for that job? I have heard Electrolytic capacitors are not good for audio.

thank you for you time,

Rex
 
Depends where you're putting the capacitors. Caps often respond badly to the impedance peak at the resonance of the driver, increasing power delivery massively over that narrow band.

Better would be to use a much smaller (and cheaper) cap on the amplifier input.

Chris
 
I have noticed that it is starting to sound a bit distorted like its going to blow.
All the time or only at high volumes? If it's happening at very low volumes too either the speaker(s) has already been irreversibly damaged or it's not the speakers. Try also gently pushing the cone of the speaker back and forth. If you hear or feel scratching noises the voice coil has been overheated, come unwound and the driver is toast. If everything feels smooth it is probably ok.

One thing to understand about speaker drivers is that while they have a quoted power rating it is only valid as long as the excursion limits are adhered to. When a driver is pushed outside of it's linear excursion range (xmax in the datasheet), the power handling becomes dramatically reduced as the voicecoil heats up significantly more as it moves outside of the magnetic gap.

Depending on the configuration of the enclosure you have the driver in, at low frequencies the driver may be pushed past linear excursion limits at only a few watts. Building a pass high pass filter at the output of the amplifier is non-trivial due to the low frequency mechanical resonance of the driver. It is better/easier to implement a line level filter before the amp. Be aware that depending on what type of music you listen to, implementing a 100-200Hz high pass filter is going to have a dramatic effect on the sound of the speakers.
If your amp or any part of your system has a bass tone control it would be easiest to simply turn that down a bit. Consult the datasheet of your speakers and find out what the xmax specification is, then have a close look at how far the cones are moving when you listen to music. You may need to turn down the bass further when listening at higher volumes to avoid exceeding xmax.
 
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Also worth noting that there are no standards for power ratings so the numbers are not very useful and cannot be compared across brands (or sometimes even within brands). It is typically safer to have too much power than too little and an amp that clips gracefully. And judicious with the volume control.

I have blown lots of speakers, but not any FRs personally (i have put screwdrivers thru them or otherwise damaged the cones).

What is your FR speaker?

dave
 
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… damage from transient noise spikes from hot-jacking inputs or shorted DC supply rails on SS amps

Thanx to Terry for the death of the original set of Bud EnABLed FE127e, and to The Geek for not considering that the line voltage might drop to 106V when he designed the reg in his piece of kit causing the death of a very pretty set of FE126eN.

dave
 
Don't forget my own little mini-aleph build that went awry after a few hundred hours - honestly you could see the voice coils glowing a dim orange through the dust caps. Another case of voice coils melting to protect the power amp's mains fuse - another set of FE127E IIRC
 
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