Normal
Re: matching amp with speakersOne interesting tidbit: The majority of voice coil heating comes from mid frequencies, 100Hz - 800Hz. This is because at these frequencies there is insufficient voice coil movement (excursion) to really cool the coil, and the impedance curve has approached nominal - so the speaker is consuming the expected amount of power. While it takes a lot of "power" (really volts) to drive subwoofers, the impedance is very high at these frequencies and excursion provides lots of cooling, so VC heating is quite low! Below is an 18SW115 impedance curve so you can see what I mean. This is why it's so hard to find a really good midrange, they have to take a lot of heat - more than you'd expect from the data sheet.[ATTACH]153297[/ATTACH]
Re: matching amp with speakers
One interesting tidbit: The majority of voice coil heating comes from mid frequencies, 100Hz - 800Hz. This is because at these frequencies there is insufficient voice coil movement (excursion) to really cool the coil, and the impedance curve has approached nominal - so the speaker is consuming the expected amount of power. While it takes a lot of "power" (really volts) to drive subwoofers, the impedance is very high at these frequencies and excursion provides lots of cooling, so VC heating is quite low! Below is an 18SW115 impedance curve so you can see what I mean. This is why it's so hard to find a really good midrange, they have to take a lot of heat - more than you'd expect from the data sheet.
[ATTACH]153297[/ATTACH]
