Suggestions: Versatile PA System

[varmonter]

Originally Posted by nhbiker1961

Over the 30 yrs of gigiing, from full bands to duos, I have found Peavey products bulletproof. I have droped PA's, mics ( I am using peavey mics too) and they just keep going. My last PA which I still have in my music room has got to be 20 yrs old and the only thing I replaced on it was the fan which took me about 15 minutes.

I too can attest to peaveys road worthyness.
Had a 600b head back in the 80s.it fell off
A waitress stand and a 3 foot stage for
A drop close to seven feet.hit the floor.
Bent some 1/4 inch plugs.but it kept
Working.. In regards to power.don't equate power
With loudness.
Power
Gives you better sound quality at a lower
Volume.so in small intimate venues you
Can keep the volume down and maintain
Quality.I would not do less than 1000 watts.
Really makes a difference at low volume.
And when you need it..its there.

[Bobby1note]

Deleted,,,,double post.

[Bobby1note]

Originally Posted by varmonter

I too can attest to peaveys road worthyness.
Had a 600b head back in the 80s.it fell off
A waitress stand and a 3 foot stage for
A drop close to seven feet.hit the floor.
Bent some 1/4 inch plugs.but it kept
Working.. In regards to power.don't equate power
With loudness.
Power
Gives you better sound quality at a lower
Volume.so in small intimate venues you
Can keep the volume down and maintain
Quality.I would not do less than 1000 watts.
Really makes a difference at low volume.
And when you need it..its there.

Required power, boils down to the "efficiency" of the speakers. A 200w amp for example, can produce more volume than a 1000w amp,,,, depending on which speakers it's mated to. Speaker efficiency (or, sensitivity rating) is usually expressed as xxdB/1 watt/ at 1 meter. Once you know the sensitivity(power @ 1 watt), just keep doubling the input-power, and increase the speaker output by 3dB at each doubling, and this will give you the total output of your speakers.

Example; let's say you have a 1000w amp, and your speaker has an input- sensitivity rating of 90dB/at 1 watt/ at 1 meter. As you apply power, your speaker output(SPL,,,sound-pressure level) will look like this;

90dB/...... 1w/ 1m
93dB/...... 2w/ 1m
96dB/...... 4w/ 1m
99dB/...... 8w/ 1m
102dB/... 16w/ 1m
105dB/... 32w/ 1m
108dB/... 64w/ 1m
111dB/.. 128w/1m
114dB/.. 256w/1m
117dB/.. 512w/1m
120dB/ 1024w/1m

Example 2; a more efficient speaker, which has for example, an input-sensitivity rating of 100dB@1w/1m,,,, then your speaker output will look like this;
100dB/...1w/ 1m
103dB/...2w/ 1m
106dB/...4w/ 1m
109dB/...8w/ 1m
112dB/..16w/ 1m
115dB/..32w/ 1m
118dB/..64w/ 1m
121dB/,128w/ 1m
124dB/ 256w/ 1m
127dB/ 512w/ 1m
130dB/1024w/ 1m

Now, you can't keep on doubling power without limitations of course, or you start getting into "power compression". In other words, at one point the next doubling of power will yield less-than a 3dB increase,,,, and it gets worse(more-compressed steps at each doubling) as you add more power. Using the above example of 130dB/1024w/1m,,,, you might get 131.5dB/2048w/1m,,, etc. At the next doubling (4096w), you might get 132.25dB/4096w/1m. (and you're probably calling the fire department )

[nhbiker1961]

Originally Posted by Bobby1note

Required power, boils down to the "efficiency" of the speakers. A 200w amp for example, can produce more volume than a 1000w amp,,,, depending on which speakers it's mated to. Speaker efficiency (or, sensitivity rating) is usually expressed as xxdB/1 watt/ at 1 meter. Once you know the sensitivity(power @ 1 watt), just keep doubling the input-power, and increase the speaker output by 3dB at each doubling, and this will give you the total output of your speakers.

Example; let's say you have a 1000w amp, and your speaker has an input- sensitivity rating of 90dB/at 1 watt/ at 1 meter. As you apply power, your speaker output(SPL,,,sound-pressure level) will look like this;

90dB/...... 1w/ 1m
93dB/...... 2w/ 1m
96dB/...... 4w/ 1m
99dB/...... 8w/ 1m
102dB/... 16w/ 1m
105dB/... 32w/ 1m
108dB/... 64w/ 1m
111dB/.. 128w/1m
114dB/.. 256w/1m
117dB/.. 512w/1m
120dB/ 1024w/1m

Example 2; a more efficient speaker, which has for example, an input-sensitivity rating of 100dB@1w/1m,,,, then your speaker output will look like this;
100dB/...1w/ 1m
103dB/...2w/ 1m
106dB/...4w/ 1m
109dB/...8w/ 1m
112dB/..16w/ 1m
115dB/..32w/ 1m
118dB/..64w/ 1m
121dB/,128w/ 1m
124dB/ 256w/ 1m
127dB/ 512w/ 1m
130dB/1024w/ 1m

Now, you can't keep on doubling power without limitations of course, or you start getting into "power compression". In other words, at one point the next doubling of power will yield less-than a 3dB increase,,,, and it gets worse(more-compressed steps at each doubling) as you add more power. Using the above example of 130dB/1024w/1m,,,, you might get 131.5dB/2048w/1m,,, etc. At the next doubling (4096w), you might get 132.25dB/4096w/1m. (and you're probably calling the fire department )

I bet you're a blast at parties?

[jwp2]

So basically, the efficiency of a speaker makes a big difference in volume. For example, I have a Fender Vibro Champ that puts out 5 watts. I installed a more efficient speaker and it is literally twice as loud as it was with the old speaker. So while wattage is something to consider, so is speaker efficiency.

[Bobby1note]

Originally Posted by jwp2

So basically, the efficiency of a speaker makes a big difference in volume. For example, I have a Fender Vibro Champ that puts out 5 watts. I installed a more efficient speaker and it is literally twice as loud as it was with the old speaker. So while wattage is something to consider, so is speaker efficiency.

Yep, that's pretty well it in a nutshell. What that doesn't tell you however, is the increase in distortion level, as you increase input-power.

When it comes to powering 2-way speakers with a monoblock amp-module, it gets a bit more complex, but it's the same basic idea. The difference is, one of the drivers' input-power(usually the high-frequency driver), will have to be "limited".

Example; a 2-way passive speaker, with a 200wRMS woofer, and a 25wRMS HF driver, powered with a 200w mono-amp,,,,. You couldn't "send" all 200 watts into the 25w HF driver, or you'd burn it,,,, so the amps' output into that 25w HF driver, has to be limited. The woofer though, would be fine since it's rated at 200wRMS.

When it comes to bi-amped powered speakers, you'll seldom (if ever) find a sensitivity-rating, so you basically have to trust the manufacturers' claims for max or continuous output. Unfortunately, that allows some manufacturers to "market" those speakers as being "more than they actually are". (marketing BS). Example; many manufacturers today, use inexpensive high-powered digital amp-modules to create the impression that this loudspeaker is REALLY powerful,,,, maybe two 500w amp-moduless, so they can "market" that magic 1000w "rating". In actual fact, each of those 500w modules, would have to be "limited", so they don't deliver more power than can be handled by the individual drivers which they are powering. Example; a K-series box rated at 1000w's, has two 500w amp-modules, one for the woofer,,, and one for the HF driver. That HF driver however, has a 25w rating,,, so it's pointless (other than for marketing BS), to use a 500w amp-module to power that driver..... but hey,,,, big numbers "sell" loudspeakers.

I don't want to pick-on QSC by the way,,,, most manufacturers do the same nowadays, and they're constantly trying to out-do each other with nonsensical power-ratings. 1400w ratings seem to be common now, but many aren't any louder than those with less-than half the power-rating.

[Bobby1note]

Originally Posted by nhbiker1961

I bet you're a blast at parties?