CMS Author Craig Vecchione Posted February 2, 2006 CMS Author Share Posted February 2, 2006 Originally posted by Q moder So what is actually meant by program rating then? Actually? Nothing. There's no real standard. Yamaha's Sound Reinforcement Handbook says, "Program (or continuous program) power ratings are basedon the power of a complex waveform that simulates actual program material. This power rating will always be higher than the continuous power or rms power rating. Unfortunately there is no standardized program for this rating, so different manufacturers' program ratings cannot be directly compared". Link to comment Share on other sites More sharing options...
Members Q moder Posted February 2, 2006 Members Share Posted February 2, 2006 Why put it then? After all by following their rating then some companies will obviously have warranty problems that they themselves will be inviting to happen. Link to comment Share on other sites More sharing options...
Members Unalaska Posted February 2, 2006 Members Share Posted February 2, 2006 Many people won't follup on a warranty after too much power is applied or whatever the reason or the season is. Bigger numbers = bigger sales numbers. I wish there was some kind of standardizing that could be done but there are many many apps for speakers that require different parameter that there is no one size fits all app. On the budget end of the MI market though specs are routinely hyped and those who use the gear aren't educated on to look for. p Link to comment Share on other sites More sharing options...
CMS Author Craig Vecchione Posted February 2, 2006 CMS Author Share Posted February 2, 2006 Originally posted by Q moder Why put it then? After all by following their rating then some companies will obviously have warranty problems that they themselves will be inviting to happen. Calculated risk. Most MI gear doesn't get used very often within the warranty period. Of the gear that's used, a good percentage is cared for and used well within spec. The gear that abused might make it out of warranty. The gear that fails may or may not ever be returned for warranty. The gear that's returned may or may not be a valid claim. Weigh the warranty claim numbers against the increased sales generated by having competitive 'specs'. Obviously it works, since every manufacturer does this. Link to comment Share on other sites More sharing options...
Members dboomer Posted February 2, 2006 Members Share Posted February 2, 2006 Originally posted by JohnnyGraphic This makes it all the more difficult for some of us the figure out exactly what we're supposed to be looking at. I took a look at the JBL website which goes into depth as far as how they come up with their power ratings. I'm still confused. RMS = ??? to JBL's specs? Johnny RMS =RMS ... but different manufacturers use a different bandwidth at their rated power ... so RMS at WHAT frequency? JBL for instance uses a testing standard called EIA RS-426A. They start with pink noise and shape it by rolling off the lows at 90 Hz and the highs at 1.6k. That leaves a signal that gives maximum output at 320Hz. Then thay run the test by supplying the RMS power for 8 hours. So their spec is "so much power, for 8 hours at those frequencies". Their speakers will support that power just like they say. The problem as we see it is ... that ain't the way you run a sub-woofer. Their test signal is 13 dB down at 20 Hz for instance. So if you were running 20Hz their rating is 1/200th of the published number. That's why people "burn" speakers when they "think" they are within the spec. They are NOT operating the speaker within the spec in the real world. Link to comment Share on other sites More sharing options...
CMS Author Craig Vecchione Posted February 2, 2006 CMS Author Share Posted February 2, 2006 Originally posted by dboomer RMS =RMS ... but different manufacturers use a different bandwidth at their rated power ... so RMS at WHAT frequency?JBL for instance uses a testing standard called EIA RS-426A. They start with pink noise and shape it by rolling off the lows at 90 Hz and the highs at 1.6k. That leaves a signal that gives maximum output at 320Hz. Then thay run the test by supplying the RMS power for 8 hours. So their spec is "so much power, for 8 hours at those frequencies". Their speakers will support that power just like they say. The problem as we see it is ... that ain't the way you run a sub-woofer. Their test signal is 13 dB down at 20 Hz for instance. So if you were running 20Hz their rating is 1/200th of the published number. That's why people "burn" speakers when they "think" they are within the spec. They are NOT operating the speaker within the spec in the real world. Or are they? Unless you're playing some pretty extreme synth material, just how much program do you expect to see at 20Hz? I don't know about you or others, but I make sure I've got a 30Hz HPF filter on the amp, and the driverack HPF is set to 35Hz with a 24dB BW slope. I neither expect nor want anything at 20Hz or near it. The fact that RS-426A doesn't equally address the extreme low end of the response graph doesn't necessarily mean the speaker can only handle 1/200th of the published number....it only means that's where it was tested. Durability at 20Hz is an unknown quantity. Unless some comprehensive test is developed and adopted univerally, there will always be ways to use specs to some subjective purpose. IMO it's a near complete lack of understanding the rig they're running, in combination with gross overpowering, that results in the vast majority of speaker failures. People run big amps wide open, and fail to apply any form of filtering or limiting to protect the drivers from stuff that doesn't sound good anyway. Despite often ridiculous specification creep these days, you really do have to try pretty hard to blow up a modern driver. Link to comment Share on other sites More sharing options...
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