kuantan Posted February 26, 2002 Share Posted February 26, 2002 Why don't speaker manufacturers state wattage consistently? That is, why do some state RMS and others in "Total System Power" or "Maximum Burst Output"? As I understand "Total System Power" or "Maximum Burst Output" are really only measurements at a momentary peak performance. Since RMS is a measurement or formula based on longer and more consistent output, isn't RMS the more accurate measurement? Understandably, manufacturers may shy away from RMS measurements since they are typically half those of other measurements (200W RMS vs. 400W Total System Power). To the average consumer bigger numbers mean better. Any thoughts on this? Quote Link to comment Share on other sites More sharing options...
lynnm Posted February 26, 2002 Share Posted February 26, 2002 I think you answered your own question except to say that some power ratings published by manufacturers can be even more misleading. I have seen a rating of 1000 w. per channel specified for a setof computer speakers driven by an amp that might be able to put out 20 watts RMS on a good day. ------------------ It is meet to recall that the Great Green Heron rarely flies upside down in the moonlight - (Foo Ling ca.1900) Quote Link to comment Share on other sites More sharing options...
JohnA Posted February 26, 2002 Share Posted February 26, 2002 The Marketing section always wants to show a big number to impress the ignorant. The best ratings for a speaker would be Long Term Continuous Power (max power the speaker could absorb for 1 hour without damage) and instantaneous peak power (max power a speaker could absorb for a brief interval like 10 milliseconds without damage). Most driver OEMs spec their drivers that way. For instance, those ratings for the K-77-M seem to be 2 watts continuous and 10 watts instantaneous. John Quote Link to comment Share on other sites More sharing options...
Ray Garrison Posted February 26, 2002 Share Posted February 26, 2002 I agree that the specs you see are usually the result more of marketing demands than engineering, but on the other hand... If a speaker manufacturer really wanted to state the maximum power it was safe to drive their speakers with, how would they state it without the spec being so complicated that it wasn't very helpful? I mean, if my speaker could safely take a kilowatt of short term power at, say, 1kHz without any damage, but if you put that much power in centered on, say, 20kHz you'd fry the high pass network and maybe the tweeter also, what do I do? Use a full range signal to test maximum short and long term levels? And would that be pink noise spectrum or white noise? Or state something like "This speaker can safely handle a momentary power input of 1,867 watts provided that the power level is not held constant for more than 239 milliseconds and does not contain significant spectral components above 5,500HZ. The full bandwidth limit (20Hz to 20kHz) for a full spectrum input containing equal power in each octave (logorithmically decreasing with frequency) is 285 watts unlimited duration, 529 watts for durations of less than 10 seconds, 815 watts for durations of less than 1 second, 1,100 watts for durations of less than 200 milliseconds, and 4,500 watts for durations of less than 10 milliseconds. These power levels represent total power summed for all frequencies and corrected for frequency-specfic system impedence, and are invalid is sourced from an amplifier having an output impedence of greater than .855 ohm due to insufficent damping factor." ------------------ Music is art Audio is engineering Ray's Music System Quote Link to comment Share on other sites More sharing options...
JohnA Posted February 26, 2002 Share Posted February 26, 2002 Now Ray,..... I write a bid spec every so often. Everything cannot be precisely specified and still put it on one sheet of paper. IOW, anybody wanting to scam the public can. There does seem to be a standard for pro gear power handling. That or something like it could easily be adopted by the home audio industry. It would probably preclude most power absorption ratings above 100 watts. Quote Link to comment Share on other sites More sharing options...
TheEAR Posted February 26, 2002 Share Posted February 26, 2002 Simple Just stay away from non RMS ratings and the 1 KHz circus jokes.If you see PMPO just turn around and walk away,it stinks like a major scam. Any serious amplifier will be rated in RMS full bandwith and the spec will be all channels driven.Few do this(Outlaw is one of the few budget oriented who do this,ATI too!). I see so many 400 and 500W reciever for under $300 it stinks.They are rated this way to catch fish and fool the sheep.These recievers often use under 3 AMPS under max output and weigh under 20lbs! Talk about ripoff A solid 150W per channel 5 channel amp weighs 60+ lbs. Amp alone,the transformer and heatsinks take 40lbs at the elast unless they are a copy of Bob Carver's Sunfire/Lightstar.It may be hard to belive but the SUnfire Signature HT amp delivers over 400W RMS full bandwith all channels driven and weighs around 50 lbs. This amp,providing the outlet can keep up delivers over 800W per channel! Now this is someting else,and the Sunfire amps sound light years better then the old Carvers.In fact the Carver Magnetic Field amps sound like locomotioves on Klipsch large speakers.Note,great amps double the output when load is greater,example 200W into 8 Ohms and 400 into 4 Ohms.And great amps still double at 2 Ohms!Is this a must,NO.Its a sign the power supply has reserve and the output stage is overdone. Ray I agree with the speaker power ratings,it would be tricky and most would get mixed to the point of no return.I know my Klipsch RF-7's can take over 100W at just about any(ahem the tweeter does not get too many watts) freq. above 50Hz with ease and belt insane SPL with a few watts. In contrast the Contour 3.3's are power suckers,they gob power and ask for more.The Denon 3801 can drive the Klipsch easy and gets hot like a heater when driving Dynes,I did manage to make the Denon shut off! Poor Denon,The 5800 can take much more abuse but does not like Dynes too much.With the big ATI,Celeste and Krell its party time.The Contour 3.3's can take way more power(than RF-7's)and likes it. Dynaudio was created for BIG muscle amps(works real well with low power tubes if high SPL is not a must),Klipsch is great for tubes and low power SS amps. TheEAR(s) Now theears Quote Link to comment Share on other sites More sharing options...
mike stehr Posted February 27, 2002 Share Posted February 27, 2002 Use Theears. Quote Link to comment Share on other sites More sharing options...
Colin Posted February 27, 2002 Share Posted February 27, 2002 good example Ray, The Ears, what you are describing is tantamount to fraud, the intentional misleading of a consumer to make a purchase decision ... ------------------ Colin's Music System Cornwall 1s & Klipsch subs; lights out & tubes glowing! Quote Link to comment Share on other sites More sharing options...
LNEtubaPLYR Posted March 6, 2002 Share Posted March 6, 2002 i would have to dissagree about the mag. field amps sounding bad on large klipsch. i have that little cube that doens't get hot (for some reason...i never found the answer to that question) but it sounds pretty good. i have only hooked my scalas up to a pioneer reciver and the carver blows it away. so watch what you say about carverIMG]http://216.37.9.58/ubb/cwmsmilies/cwm23.gif or i will make it catch on fire in front of your house! i musta got one that doesn't explode......so far anyway Rob ------------------ My 2 cents... I'll put it on your tab. Quote Link to comment Share on other sites More sharing options...
Ray Garrison Posted March 6, 2002 Share Posted March 6, 2002 LNEtubaPLYR, Wanna see it blow up? Borrow Theears Dynaudio's for a few minutes... Ray ------------------ Music is art Audio is engineering Ray's Music System Quote Link to comment Share on other sites More sharing options...
pzannucci Posted March 6, 2002 Share Posted March 6, 2002 I have yet to have a set of BIG Klipsch's heat up my old Adcom GFA-555II but if you want to bring a big amp to its knees, hook them up to some old Apogee ribbons. My MiniGrands used to make the heat sinks on the Adcom boil water. Pete Z. Quote Link to comment Share on other sites More sharing options...
Ray Garrison Posted March 6, 2002 Share Posted March 6, 2002 pzannucci, Yes, the MiniGrands were something of a tough load, but even worser were the Scintillas. I posted a link to an old Audio magazine review someplace in the forum a while back, but to cut to the chase... Audio was using FOUR of the biggest Krell monoblocks available at the time, with two per side driving the Scintillas in biamp mode. They couldn't get output levels above the mid-90's dB SPL before they were driving the Krells into hard clipping. Impedence approached 0.1 ohm in the midbass, sensitivity on the order of the low 80's... but they sure sounded nice, if you were sitting close enough to hear 'em... Ray ------------------ Music is art Audio is engineering Ray's Music System Quote Link to comment Share on other sites More sharing options...
boa12 Posted March 6, 2002 Share Posted March 6, 2002 colin brings up a good point. the ftc guidelines i think require 20hz-20khz w/ all channels driven. but obviously these must be guidelines & not law. or if not i wonder how many of these reputable makers avoid getting hauled in. or maybe it is law but there's a loophole because all or most of the components in the receivers or amps are made overseas. anybody know the legals here? ------------------ My Home Systems Page This message has been edited by boa12 on 03-06-2002 at 04:11 PM Quote Link to comment Share on other sites More sharing options...
boa12 Posted March 6, 2002 Share Posted March 6, 2002 like ray says, this interent is great. just a quick search & this was the 1st that popped up: http://www.qscaudio.com/news/cssbypq.htm ------------------ My Home Systems Page Quote Link to comment Share on other sites More sharing options...
discorules Posted March 6, 2002 Share Posted March 6, 2002 This is one of the reasons I go with HK. They spec conservatively all channels driven, full bandwidth. In fact I just read a recent test done by a British Hi Fi online magazine. The HK 5000 they tested easily met and surpassed the power rating, all channels driven. A Denon receiver they tested dropped power considerably from the advertised rating when all channels were driven. Quote Link to comment Share on other sites More sharing options...
TheEAR Posted March 6, 2002 Share Posted March 6, 2002 "Your typical speakers are going to present 6-ohm to 32-ohm load to an amp while playing music, and so what does this have to do with delivering 2KW at half an ohm? And why should anyone buy such a stupid thing? Much better to have an amp that actually is designed to drive speakers, and has HEADROOM for millesecond music peaks that doesn't require 60-pounds of useless heatsinking. The "fad" if there is one, and the "marketing mumbo-jumbo" is convincing people they need a voltage source instead of an audio amplifier." Tubey talk It shows you dont like amps that can drive tough loads too well.As far as heatsinks are concerned they are a must in almost all SS amps.The only amps that dont need heatsinks are Bob Carver inventions.The Carver Lightstar and the newer SUnfire amps dont need heatsinks(the chassis is the heatsink). Speakers going only down to 6 Ohms,your speakers maybe.I have Dynes and they dip around 3 Ohms,often stay around 4. You will not tell me what to like in audio,you like you little glowing tweaker's tube amps and I like my BIG powerful solid state amps. And the 1 Ohm capable amps are great for subwoofers,other than sub use I agree any rating below 2 Ohms is just for show. Wow a new trend...hate the BIG powerful amp because its capable of doubling its power with load!LOL Hate the amp because it does not need an output transformer,hate a good SS amp with a solid power supply. Too much LOL Only a tubephile can start this! TheEAR(s) Now theears Quote Link to comment Share on other sites More sharing options...
Manuel Delaflor Posted March 6, 2002 Share Posted March 6, 2002 In my opinion wattage ratings are *almost* meaningless. I think we need SPL numbers given in full range and stated at +/- dB. For example, in the case of an amplifier, those numbers should say something like this: "Our amplifier can put 110dB at one meter from 20Hz to 20Khz at +/-5dB on a speaker with 88dB of sensibility". With this system it would be irrelevant if the amplifier have 200watts RMS at 1Khz or full bandwith, or 10,000watts PMPO. Quote Link to comment Share on other sites More sharing options...
Audio Flynn Posted March 6, 2002 Share Posted March 6, 2002 Ray, Great spec Colin, Agreed Quote Link to comment Share on other sites More sharing options...
TheEAR Posted March 7, 2002 Share Posted March 7, 2002 mdeneen, "What poorly designed subwoofer dips to 1-ohm? Who would buy such a thing? Why? Who would be silly enough after designing it to try to sell it?" SVS subs are 4 Ohms and this way they "extract" more power from amps then poor 8 Ohms drivers. Who cares if real world speakers dont drop to one Ohm. Why did I spend two(ok a bit less)years of savings on an amp?Because to me its worth it,I am an audio lunatic.And when I pay I want big power at 8 Ohms and an amp capable of doubling its power down to at least 2 Ohms. And in this case the Krell FPB600 delivers,it can drive any speakers made and drive them to thier limits. Do I need this? NO Why do some buy sports cars capable of 180+ MPH? Because they can,not they will EVER use them at these speeds. In the end its what makes you tick in audio,me its BIG power amps,a multitude of subwoofers and an army of speakers.I use Monster M Series M2.4B wires with my Klipsch R series,overkill? You bet TheEAR(s) Now theears Quote Link to comment Share on other sites More sharing options...
JohnA Posted March 7, 2002 Share Posted March 7, 2002 Ratings aside, I don't believe ANY amp is so linear that it would double its power at clipping when the impedance is halved. There are plenty of amps that are *rated* at 250/500/1000, but they will typivally clip at something along the lines of 350/520/1000. My old B&K M-200 was a good example. John Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.