Loudspeaker Power Handling
Copyright 2013 © Troels Gravesen
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A frequent question is how many watts a given construction can handle. I wish I could give a precise answer, but I can't because it depends on what signal the speaker is fed - and for how long, continuous for e.g. two hours or a short term impulse. The latter is often specified as double of continuous wattage, e.g. "music power".
None of these specifications make much sense in the real world. Think of a 100 watt light bulb (old-time bulb) and you will how hot this gets. Imagine the same amount of heat being subjected to a 1-1½ inch speaker voice coil. That is a lot of power and the voice coil needs serious cooling to cope with this amount of power. The voice coil is only cooled by air and the surrounding metal parts will help absorbing some of the heat generated. No wonder some PA drivers have heat sinks bolted to the magnet to help getting rid of the heat. Most hifi drivers do not have a heat sink and are generally less rugged compared to PA drivers, being designed specifically for long term high power handling.
Regarding my own speakers, I have have some recommendations on what kind of amplifier should be used for a given loudspeaker based on the choice of drivers and overall system sensitivity.
Some general guidelines on min/max wattage required for some of my speaker constructions:
TQWT: Recommended 10-30 watts.
DTQWT(10 and 12"): Recommended 20-60 watts. Don't use 250 solid state watts unless you're always is in control of playback level.
QUATTRO: Recommended 20-50 watts.
OBL-11: Recommended 30-100 watts (due to the 8008 having a high-pass filter, this speaker can handle quite a lot of power and play immensely loud).
All Jenzen speakers incl. ATS4, NEXT4, Discovery-4 and Illuminator-5: Recommended 50-250 watts.
All 6" +1" constructions, being stand-mount of floor-standers: Recommended 50-100 watts
All 2½-ways and 3-ways based on 6" basic driver(s): Recommended 50-100 watts.
All 2-way minis based on 5" basic driver: Recommended 25-50 watts.
This page on amps for TQWT/DTQWT is about this issue: http://www.troelsgravesen.dk/DTQWT-amps.htm. The lesson to be learned from this is that we do not feed a 95 dB speaker for domestic use 400 solid state watts. This doesn't mean it cannot be driven from such an amp, but if your kids turn the volume knob all the way we may blow our drivers. Using 400 watt solid state amps we better think about what kind of speaker to use and maybe we have to look for PA drivers in case we also want to play seriously loud. Very few "hifi" speakers can handle disco levels.
Obviously we can run all of these speakers from significantly higher powered amps as long as you know what you're doing. I shall not reiterate all the writing and cleaver thoughts others have done on this difficult issue, only recommend taking a deeper look into the articles linked below:
LOUDSPEAKER POWER RATINGS - CUK Audio
Speaker Power Requirements - JBL Professional
Claus Futtrup, SEAS Sales and Marketing, sent me these links:
DPC Manual Direct link: DPC POWER
Remember: Any burned driver is always a misused driver.