The way to stop this is to put a resistor 10-100 ohms in series with the piezos, so that is what the resistor is for and if chosen correctly can roll the hf off a bit.
They don't need a crossover (although they sound a lot nicer with one, or just a simple high pass filter made from a single bi polar capacitor (trial and error is the best here)) because the impedance changes with frequency, the higher the frequency the lower the impedance, at low frequencies the impedance is very high, several thousand ohms, which is why no sound comes from them playing lows, as the frequency goes up the impedance drops until the crystal in the piezo starts to do some actual work and starts playing, if it sees very high frequencies, ultrasonic really, the impedance drops to a very low value, until it is a virtual short circuit and the crystal burns out. Piezo devices are actually rated by their voltage not watts like standard speakers, the motorolas were rated at 30v if I remember correctly which is why they were claimed to be for 100w systems (30v at 8 ohms) so if you took a couple and put them in series you had 60v, 3 was 90v etc. Two pieces of plastic that weighs less than a CD in it’s jewel case.Įdited by Elliot Thompson - 11 September 2009 at 11:11am The shipping ($29.00) is a outrageous for I would imagine the market value has gone up I remember when they would cost $3.00 each and, you could get themįor $2.50 if you bought quantity. Squared-rectangular-shaped and, not a cinlinder. Ohm and, the colour favoured chalk used to write on a black board. If I remember correctly, the resistor was 50 The reason many would wire two in a series/parallel configuration to increase If you tried to feed them 100 watts they would burn up hence, Regardless what marketing claims, they were Purchased the rights to Motorola tweeters in the mid 1990s. Those for sale may have stemmed from some oldĬabinets if, they are indeed made by Motorola and, not the company who
Another company purchased the tools from Motorola and continued to make Motorola stopped making Tweeters in the earlyġ990’s.
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