2 watts to drive PA speakers in living room

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#22
wg_ski said:
High level BASS is what blows piezo tweeters. Overexcursion results, literally ripping the lead wires off the piezo disk. It will also distort the high frequencies being reproduced at the same time. So if you have a limited amount of power (2 watts, or even 60) the piezo is safe without a crossover. You won’t drive them to damage or severe distortion. They SOUND better across the board with a proper 4th-order-acoustic crossover between woofer and tweeter, but then again anything does. Most low end PA speakers don’t have “real”, proper slope crossovers on both woofer and tweeter - even with regular VC-driven tweeters. Only a high pass of some sort on the tweeter to prevent damage.

These low end PA speakers, even with no crossover on the tweeter do ok in PA duty if the high level low freqency is being handled by subwoofers, or as instrument amps where it isn’t trying to pump out bass.
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That was quite useful information. The only thing might be that at living room listening distances the overlap caused by a crossoverless piezo could be a bit confusing.

Thank you for your kind inputs, wg_ski. 🙏
 
#23
InvaderLex said:
well, where are you gonna sit?, at what distance? is 97db at 2w, but minus 3db for every meter of distance you add. in a room a find something around 75db to be a pleasant room volume, and 85 is considered loud, and everything above to be too loud neighbor annoying levels. 2w is enough for the guys with low power tube amps.
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Thank you Lex! Listening would not be more than 4 metres in most cases. Which means i should be good enough with only 0.25 of a watt!
 
#25
Briz said:
2W average is credible, but most of the music I listen to has a fair amount of dynamic range.
Also it depends on background noise, I live in a detached house in a fairly quiet place so there is no traffic noise or 'people next door' to interfere with the quiet bits of the music.
If you listen to rock music which is produced to be listened to in a car, you will be OK with quite low power in a quiet place.
If you listen to classical music with lots of quiet passages, against the background noise of traffic or a washing machine in the next room, or even a computer fan on your desk, you may want more watts for the loud passages.
There are plenty of cheap 20W (or more) amps available. Don't rule out the 'class D' amps either.
Maybe better to have class D in its comfort zone than Class A clipping?

The other thing is, if you like the music, you will ignore imperfections in the reproduction.
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I appreciate all the aspects you have presented. Yes, i listen usually to traditional folk music, chamber music with small ensembles, and sometimes large orchestral works such as Beethoven's 9t and similar. As you suggest, i suppose it would be appropriate to invest in a headroom of say 10 dB. A 20 watts per channel into 8 ohms amplifier is easy to manage.

Thank you for your kind inputs, Briz! 🙏
 
#27
sujat said:
Unfortunately, Wahab, this is a local manufacturer who specifies nothing about the crossover, nor do they offer any impedance plot for the piezo. How then may one determine the value of the capacitor for a 1st order point around 11,000 hz?
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Freedom666 solution is the best overall, although the value of the capacitor in serial has to be set accordingly
to the desired cut off frequency, what is sure is that using only a resistance in serial will result in a screamy sound.

When you compute a capacitor impedance use the basis that a 1F capacitor has an impedance of 0.16R at 1Hz.
increasing frequency by a factor x will decrease this number by this factor, decreasing the capacitance value by
a factor y will increase this 0.16R impedance by this factor y.
 
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