Loafing

[jgstudios]

After my last post I was given several pages of advice and information. I then went into seclusion and studied. One of the posters made a comment that the 500 Watt amp I was looking at to connect to my polk rti a9 speakers with a 90 db sensitivity would be "loafing", and I should look at a lower powered amp. I wasn't exactly sure what the term loafing meant, I had some idea, but I thought it might be some specialized Hi-Fi jargon that meant something altogether different. So I was on a quest for more info, I and played around with the SPL calculator page that someone posted as well using different numbers to crunch out various scenarios. I then came across this article with speakers of an equal sensitivity and wattage to my polks, and here's a quote from it. "A speaker that can play loudly is likely going to do a better job of small-scaled quiet music than a speaker that cannot play loudly. Audio devices do their best when they are just loafing." Now, from the article it sounds like loafing would be a good situation, but the poster left me with the impression that was not a good thing. So I take the term loafing to mean the device is barely doing any work at all is this correct? So my question is, whats wrong with loafing? I humbly ask for some clarity in this subject.

http://www.theabsolutesound.com/articles/tested-cerwin-vega-cls-215-loudspeaker/

 

[shadyJ]

Loafing means doing something with ease, so of course its good for audio equipment to loaf. The reason is that the more stressed they get, the more distortion and nonlinear they become. A speaker that is not being stressed should play below 1% harmonic distortion, and an amplifier will have much less distortion than that even. You always want to keep your equipment in their comfort zone. Although that sentence about speakers that can play loudly doing a better job of quiet music is very much an over-generalization.

 

[GrimSurfer]

Loafing is a pretty subjective term.

I think it would be more accurate to say that most products work best when operating well within their designed limits. For amps, this means that the best scenario occurs when steady state demand and peaks fall comfortably within unclipped performance specs.

Most manufacturers rate amp output in one of two ways... continuous power (FTC method or RMS) and peak power (IHF method is one of many such methods). They do so at a point either corresponding to, or just below, clipping.

Some manufacturers are very conservative in their ratings. These often demonstrate, in independent tests, to have outputs far higher than their advertised rating. In almost all cases, one can reliably presume that such products' advertised ratings are unclipped to a margin that could (and I stress could) leave a significant dynamic headroom margin.

Power is often misunderstood. You don't need 500W per channel of continuous or peak output for normal listening in a normal (~3000 cu ft or smaller) room... or for aggressive listening in a normal room.

You only need enough power to reach a desired spl without the amp having to extend itself beyond the point where it runs out of dynamic headroom, clips, distortion starts to rise exponentially, or overheats.

 

[Swerd]

I used the term "loafing". And I used it as a very subjective term, not at all technical. I'm sorry if that caused confusion. It really comes down to money and amplifier over-kill. How much are you willing to spend?

Your speakers, if I remember correctly, are on the sensitive side, about 90 dB. They should be able to play very loud, 90 dB, when driven by 1 watt, if you listen 1 meter away from the speakers. Most of us listen at distances about 9-10 feet or more, but at levels lower than 90 dB. So how much power do you need to avoid causing an amp to distort or begin clipping?

I suggested that 500 watts might be over-kill for your speakers. If the cost of those amps isn't too much for you, they should be no problem. But for less money, 200 watt/channel amps would achieve the same results for you.

In audio there are often questions of "how much power is enough"? Some would answer that "more is always better". But others would answer "good enough" is all you need. More than "good enough" is a waste of money. And the debate continues from there. It's not too difficult to estimate how much power is enough for a pair of speakers, in a given room, with given listening tastes. No one other than you knows how much money you're willing to spend.

 

[GrimSurfer]

FWIW, I'm totally cool with loafing. It's clearly understandable when the various issues behind the term are understood.

Also (LOL) I used the term "pretty subjective". Stupid on my part... something is either subjective of not, there are no degrees!

 

[ryanosaur]

I think there’s also an element of pragmatism in that statement warning against loafing: consider that polks speakers are designed to handle large levels of energy being fed into them... that is almost unlistenable if tapping into that potential. It has been written, for this reason, thats polks are sort of foolproof/bulletproof in that its very difficult to overdrive them, thus damage them. Enter the idea that “you should have an amp that doubles the rms rating of your speakers.” Suddenly, polks are power hungry speakers that take a lot to drive! Yes, I’ve seen that in writing, and was even told that by salespeople!
Anyway, the pragmatism at AH is in the attitude of some that you shouldn’t buy it to not use it. Amps are the perfect example for this, of course, and one of the more... shall we say: controversial components on the market. You don’t actually need 500w to drive the speaker... you will quite possibly never actually use more than 32-64 watts while being in the same room as them. So why spend the money on that amp, when you can possibly buy fewer watts at lower distortion levels/cleaner power, or just flat out save money to apply to another future upgrade?
Don’t misunderstand me, I see the value in both sides. I like that my amps aren’t working hard (yet I do have the potential to drive my speakers to reference level dynamic peaks), and that my speakers aren’t working hard, and that my subs aren’t working hard. I also bought wisely, with sale prices and smart gear... thus fulfilling both angles of pragmatism! Not that I didn't have people telling me to buy the model 5000 amp over 5 2200s, or just 3 2200s. There was plenty of that!

Regardless, It's not a bad thing to have dynamic headroom hanging out for those times when you need it. If you are comfortable spending for that amp, it is your system. No real reason not to, as long as you understand the gear, how it works and interacts with everything else in the system, and use it responsibly and not destroy your hearing. (That's my pragmatism ) Have fun and enjoy!