can a 50 watt amp put out 100 watts???

[Chuck H]

I remember the first time I saw an audio device that stated it's peak power as it's performance wattage on the packaging. After a lifetime of seeing standardized RMS ratings on packages I was pretty shocked to see a cheap 5:1 speaker system with a particle board bass driver and little plastic cube satellite speakers rated at 1000W!?! I'm 100% certain I could have plugged my 20W guitar amp into this thing and blown it to smithereens.

Peak power (handling or produced) is a useless figure for music system evaluation or ratings and using it to imply the apparent suitable of such systems is misleading at best and downright dishonest at worst. And, if I'm not mistaken, it's illegal to knowingly practice dishonesty in product representation. Too often though the consumer electronics industry slithers under the radar because no one with proper knowledge polices regulation.

[loudthud]

Kirk:" Scottie, I need more power!".
Scottie:" "I've given it all she's got, Cap'n."
Aah: dilithium crystals

This is nonsense. Everyone knows you must use a flux-capacitor.

[überfuzz]

I've got a scientific rating system that is based on extensive empirical evidence. Luckily it is possible to map this system to the Watt system.
0 - 5 W : bedroom amp
6 - 20 W : Useless
20 - 40 W : The rehearsal studio range
41 - 84 W : The gig range
85 : Twin reverb
86 - inf : Spinal tapp

[Jazz P Bass]

Hah!
There is local band here in PA called that.

[g1]

There is local band here in PA called that.

Called what?

[Jazz P Bass]

'Flux Capacitor'

[The Dude]

What's lost in most of these or this type of discussion is that double the power is not twice as loud anyway. It's a relevant discussion for those who actually want to learn about measuring power output. But, for those who think their amp will be twice as loud with all that extra power...... In other words, getting back to the original post, I won't even argue (yes or no) about the monobloc putting out 400 watts. There are too many variables. It won't be twice as loud anyway.

[SpareRibs]

Hello,
Isn't the output measured by how many stickers it has on it ???

[Chuck H]

No. The output is measured by the salesman's commission.

[teemuk]

What's lost in most of these or this type of discussion is that double the power is not twice as loud anyway.

This. The scale is logarithmic so even tinyest increase in perceived volume requires substantial increases in output power.

Yes, the modern amps are starting to reach such output power levels that the rating system requires series re-thinking. Someone joked earlier about producing 5kW from a 3kW outlet, but this is not exactly too far off from what happens in practice. See, the capacitance of the amp's power supply stores energy - which is its whole point - so to produce momentary peak power it is indeed possible to drain that energy and produce more output power than what the amplifier draws from the mains continuously or in average. Yes, such amp may also need to incorporate features to "self-protect" under sustained high power output conditions.

On the other hand, we have amplifiers designed with that continuous power output in mind, which may produce substantially less peak power than the modern designs that deliberately exploit burst power capabilities.

Which one is more powerful? In practice?

Are we listening to continuous sine waves or musical signals that largely consist of transients and where crest factors can be moderately high?

If one amp produces 1KW for, say, 20 ms burst but only 100W continuously it may, from basis of continuous power output, seem less powerful than an amplifier that can produce 200W continuously but only produces 400W for the 20 ms burst. But is is really less powerful, if in practical situations we are actually asking the amplifier to produce only short durations of high power output, after which everything settles again to very low output power levels in average. One amp produces 1KW and the other only 400W. So which one was more powerful again?

Amplifying music signals largely requires high power output only for transient reproduction, so the burst power rating isn't exactly totally irrelevant, though somewhat misleading.

Are we driving motors with the amplifier or reproducing musical signals? Which one -really- counts more in the application, that the amplifier can sustain a continuous sine wawe output for years (we don't listen to continuous sine waves) or that it can reproduce that momentary signal transient cleanly? Hint: we listen to signals with moderately high crest factors and transients.

[Mick Bailey]

My traditional method of measuring output power - 1khz sine wave into a resistive load - doesn't work with some amps. They give disappointingly low figures using this method and sometimes the limiter will kick in, or it can look like there's a clear fault with the equipment because the output is so low. A mixed-signal audio test though will often give impressive results.

How you measure the actual power with that type of amp is another thing. Establishing a standardized, repeatable procedure isn't straightforward.

[J M Fahey]

Personally I use the traditional continuous sinewave at the edge of clipping, at some convenient frequency, usually 400 or 440Hz because it's smack in the middle and more bearable than 1kHz (if there is some speaker involved), may easily use 100Hz or 5kHz if measuring a biamped or triamped system, and per the FTC old system, at least for an hour.

Other much lighter demands ratings may apply for Music lovers listening to a Symphony at home through electrostatic or bookshelf speakers but I **rarely** see them, my everyday customer is a red eyed Musician/PA/DJ guy who continuously overdrives his power amp and speakers by 10dB, so dynamic range is *crushed* and signal becomes clipped tops audio wave, level brutally evened out by clipping or, best case, through of brickwall limiters.

Compared to such Real World audio program, sinewaves are but a mild equivalent.

By the way, friends of mine run *huge* PA companies (get hired by Roger Waters, Peter Gabriel, Madona, etc. on tour to play Football Stadiums) BALS || Buenos Aires Live Show , *do* use those Lab Gruppen amps (lately switched to Powersoft) to drive subwoofers, heavily limited, and if you stand by the speakers all you hear is a continuous indistinct rumble, think an underground train passing below you or a distant Space Shuttle takeoff, a fair representation is filtered (and clipped) pink noise.

And although they now use the lightweight digitals, tell me the main advantage is weight and reduced rack space, but they still swear by their old AB Systems and such which they still use, only in fixed or semi fixed installations in Theaters or dance halls.
Not flying them anywhere, of course.

[Chuck H]

This is the sort of thing I was referring to. If this is an honest representation of the product then my ass is a banjo.

LG CM9950 4400W Mini Shelf Speaker System CM9950 B&H Photo Video

[Leo_Gnardo]

This is the sort of thing I was referring to. If this is an honest representation of the product then my ass is a banjo.

LG CM9950 4400W Mini Shelf Speaker System CM9950 B&H Photo Video

One review: "It's booming in my living room right now."

Better have fire extinguisher ready if you turn it up some Mr. Reviewer. Mini speakers will turn into space heaters real fast. And how do LG's amp turn out 4400W with 120V 15 amp branch circuit feeding it?

Chuck don't worry about your ass turning into a banjo anytime soon. An accordion, maybe.

[Chuck H]

Chuck don't worry about your ass turning into a banjo anytime soon. An accordion, maybe.

But I can't pick an accordion.