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Silver Member Username: ScubasteveAnnapolis, MD Post Number: 316 Registered: May-05 | I'm new to home audio, and I had a question concerning the power that companies recommend that people give their loudspeakers. It seems like most speakers you see, even if they have dual 8s and multiple midrange and tweeters will only recommend a few hundred watts RMS (if that), when the raw drivers can handle much much more power than that. Is it because the crossovers can't handle all that power, or they don't want to scare consumers off thinking that they will need to buy multi-kilowatt amplifier to run the speakers or what? |
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Bronze Member Username: Devils_advocatePost Number: 89 Registered: Jul-05 | Power handling numbers are all but meaningless in the real world. |
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Silver Member Username: ScubasteveAnnapolis, MD Post Number: 317 Registered: May-05 | would you care to explain that one? |
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Bronze Member Username: Devils_advocatePost Number: 91 Registered: Jul-05 | How detailed of an explanation do you want? There are a lot of reasons. |
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Bronze Member Username: Devils_advocatePost Number: 92 Registered: Jul-05 | Heres a short list. 1. Receiver manufacturers lie about power ratings. 2. Speaker manufacturers give the power handling characteristics as a guideline, it is by no means set in stone. 3. You are much more likely to destroy your speakers buy underpowering them (causing your receiver to go into clipping) than overpowering them (if you purchased some Bose cubes and Mark Levinson amplifiers). |
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Silver Member Username: ScubasteveAnnapolis, MD Post Number: 318 Registered: May-05 | Any time anyone could take out their schedule would be just fine. I'm not a complete audio newb who doesn't know the difference between true RMS handling, peak handling, true thermal dissipation abilites, etc. My background is in car audio where you usually attempt to have an amp (or a channel of an amp) for each component that can supply the RMS handling of the driver, assuming you believe this is a truthful claim by the speaker company. I was just wondering why this is (seemingly) different in home audio. |
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Silver Member Username: ScubasteveAnnapolis, MD Post Number: 319 Registered: May-05 | "You are much more likely to destroy your speakers buy underpowering them (causing your receiver to go into clipping) than overpowering them" I agree with that statement, but it doesn't explain why loudspeaker companies would suggest using LESS power than the drivers can handle. That means an owner is garunteed to be underpowering them, which will make him more likely to drive the amp into clipping. |
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Gold Member Username: PetergalbraithRimouski, Quebec Canada Post Number: 1048 Registered: Feb-04 | For another thing, power output capability and power input capability varies with frequency. If you can safely pump 100W of 100 Hz into a speaker, I wouldn't try pumping 100W at 10kHz. For another, since power works on a log scale it's difficult to accurately know whether you are pumping 100W or 150W since the difference in dB is so small. Since the scale is logarithmic, you may most often require less than 1W rather than 100W. |
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Bronze Member Username: Devils_advocatePost Number: 93 Registered: Jul-05 | How many amps do you know that can deliver a couple hundred watts RMS? |
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Gold Member Username: PetergalbraithRimouski, Quebec Canada Post Number: 1049 Registered: Feb-04 | I don't know that's it's true if drivers are over-spec'ed. But judging from the dainty PC-board type of crossovers often used today I wouldn't be surprised if they were the limiting factor. Now this is a crossover : http://cgi.ebay.com/New-Replacement-Crossover-Klipsch-Type-AA-PR-Cedar_W0QQitemZ 5792679238QQcategoryZ14993QQssPageNameZWDVWQQrdZ1QQcmdZViewItem :-) |
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Silver Member Username: ScubasteveAnnapolis, MD Post Number: 320 Registered: May-05 | since when is power on a logrithmic scale? SPL is measured on a logrithmic scale but thats a different story. Dainty crossovers was my first thought though... |
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Bronze Member Username: Devils_advocatePost Number: 94 Registered: Jul-05 | Either way, whether you have a amplifier that is too powerful or too weak, if you hear distortion, just turn the thing down.... As for SPL vrs power, it is somewhat important. Every doubling of power only results in a 3dB gain. So from 100 to 200 watts is 3dB. From 100 to 400 is 6dB. Not that much in the grand scheme of things. |
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Gold Member Username: PetergalbraithRimouski, Quebec Canada Post Number: 1050 Registered: Feb-04 | sigh. That's what I meant. How would you have phrased it? Start at 1W, turn the volume dial up 10dB and you are at 10W, turn it up another 10dB and you are at 100W, turn it up another mere 3dB and opps you're at 200W and you've blown something. |
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Gold Member Username: PetergalbraithRimouski, Quebec Canada Post Number: 1051 Registered: Feb-04 | Not that much in the grand scheme of things. Exactly my point. Not much SPL gain but a whole lot of Watts more required! |
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Gold Member Username: PetergalbraithRimouski, Quebec Canada Post Number: 1052 Registered: Feb-04 | Hey DA, a few more and you turn silver! |
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Silver Member Username: ScubasteveAnnapolis, MD Post Number: 321 Registered: May-05 | ahh, sorry about that, Peter. Now that I re-read, I see what you were getting at. |
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Gold Member Username: PetergalbraithRimouski, Quebec Canada Post Number: 1053 Registered: Feb-04 | No harm done. But have we convinced you of anything yet? ;-) |
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Bronze Member Username: Devils_advocatePost Number: 95 Registered: Jul-05 | Yes indeed Peter. Then just a few more weeks till gold if I keep going at this rate! |
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Bronze Member Username: Devils_advocatePost Number: 96 Registered: Jul-05 | Its just way too much information to write down coherently without spending a lot of time to formulate all my thoughts, etc. |
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Gold Member Username: PetergalbraithRimouski, Quebec Canada Post Number: 1054 Registered: Feb-04 | yeah, you registered this month so it's going up fast! Then there's Art, Paul and Jan. Boy are their counts going up quickly! |
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Bronze Member Username: Devils_advocatePost Number: 97 Registered: Jul-05 | It helps to be able to sit on here all day at work with nothing better to do. |
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Gold Member Username: PetergalbraithRimouski, Quebec Canada Post Number: 1056 Registered: Feb-04 | I've been on vacation for the last few weeks so my count went up. But the pattern won't hold... |
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Silver Member Username: ScubasteveAnnapolis, MD Post Number: 322 Registered: May-05 | "Not much SPL gain but a whole lot of Watts more required!" Isn't a 3 dB increase in SPL considered twice the audible level? |
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Bronze Member Username: Devils_advocatePost Number: 98 Registered: Jul-05 | No, 3dB is double the power. 10dB increase is considered twice the audible level. |
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Bronze Member Username: Devils_advocatePost Number: 99 Registered: Jul-05 | Also, keep in mind that most program material consists of peaks and dips. It is only those peaks that come anywhere close to maximum power; most loudspeakers of decent make can handle such peaks. |
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Silver Member Username: ScubasteveAnnapolis, MD Post Number: 323 Registered: May-05 | right...but the power for the peaks won't be there if you're chronically underpowering your speakers...trying to use 1 or 2 channels of a receiver at most to power at tower speaker with 4 of 5 drivers. Thanks for being patient with my questions. I'm trying to make my break into home audio now that I acutally have a place where I can put some speakers. |
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Bronze Member Username: Devils_advocatePost Number: 100 Registered: Jul-05 | Unless you're really pushing it hard enough to cause yourself to go deaf in a couple years, you aren't chronically underpowering your speakers. The average loudspeaker can manage somewhere on the order of 90dB with 1 watt of input. 90dB is pretty darned loud. |
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Silver Member Username: Devils_advocatePost Number: 101 Registered: Jul-05 | http://www.moultonlabs.com/articles/93aboutloud.htm This looks like some good info about sound levels... |
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Silver Member Username: Devils_advocatePost Number: 102 Registered: Jul-05 | Ohh and the tower speaker being less efficient isn't really accurate. For example, Peter's mains play at 104dB with one watt of input power. |
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Silver Member Username: Devils_advocatePost Number: 103 Registered: Jul-05 | Anyways, have a good night Steve. I'm out for the evening. I'm sure the good people of ecoustics will have more to say on the matter. |
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Gold Member Username: PetergalbraithRimouski, Quebec Canada Post Number: 1059 Registered: Feb-04 | Hey DA, you made it to silver on this very thread! scuba steve, I think you worry too much about pushing speakers to their very limit. There's more to audio than SPL. Have a good night! |
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Silver Member Username: ScubasteveAnnapolis, MD Post Number: 324 Registered: May-05 | yes!! truly there is peter, it is just always my experience that speakers preform better when their full RMS power is available to them, even if you're listening to them at low levels. Thank you both for your help. |
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Gold Member Username: PetergalbraithRimouski, Quebec Canada Post Number: 1063 Registered: Feb-04 | it is just always my experience that speakers preform better when their full RMS power is available to them, even if you're listening to them at low levels. How would it know? There are lots of recordings that I like to listen to at 90 dB or so (light trio jazz) because the instruments are more realistic at that level. That's at -30 dB on my volume dial, so 1/1000th of full power. Should the speakers care what that full power could be if they are only being fed 0.1 W peaks? |
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Silver Member Username: ScubasteveAnnapolis, MD Post Number: 325 Registered: May-05 | Well Peter, me saying that speakers sound better when powered by an amp that has the ability to produce the full RMS handling of the speaker is true in my experience. This probably has something to do with the fact that if you're listening at low volume levels, the amp is producing a signal with .0003% THD. For an example from car audio, if you power a set of focal components with your head unit, its going to sound terrible no matter what volume level you listen on. |
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Gold Member Username: PetergalbraithRimouski, Quebec Canada Post Number: 1069 Registered: Feb-04 | Ah, so you're talking about quality then. Gotcha. |