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Watts per channel, RMS... overrated?

hnash53

hnash53

Super Member
Doing a bit of research after reading in several places that most audio listening is done using 1 watt of power, I did some tests on my own very modest system.

I have a Realistic STA-76 receiver rated at 12 watts per channel, and a pair of EPI 150 speakers rated at about 88 dB sensitivity, and a second pair of "modified" EPI speakers with the same woofers and tweeters as in the 150s but in a smaller enclosure. And I run the Quatravox all the time (Realistic's simulated 4-channel or quad sound).

Using the following calculator, http://www.crownaudio.com/elect-pwr-req.htm I put in the following data: 4 meters distance from the EPI 150s (this is where I sit most times when listening to music... the second pair is located behind me about 2 meters), 88dB speaker sensitivity, and 80dB listening level (I measured what this sounds like using a dB meter... and it's LOUD... at least to me), and finally 3dB headroom for handling peak output.

The calculator says that the required amplifier power for the above level of listening is 5 watts. Yeah... 5 watts.

Another factor worth noting is the room size. I have fairly low ceilings (7.5'), and the room is fair sized... slightly smaller than 20' x 24'. But the speakers are placed in an area about half those dimensions.

The 80dB listening level is about the max I can even handle in my typical listening position. It's more like 70dB or less most of the time.

So..., at least in my case, my Realistic STA-76 has plenty of power, no?... and some to spare, right?

I read that those powering with vacuum tubes often run at 1 to 2 watts.

I know this post may revive what has undoubtedly been discussed here before... the "wattage wars."

More than discussing wattage, though, I just wish to know if I have indeed done the calculation correctly.

And if I have, I am curious as to what low-wattage but high audio quality stereo receivers I might wish to consider.

Thanks for reading, and any comments/suggestions/critical thinking welcome.
 
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Epi 150's dont look too beastly. One vintage 8'' woofer?

Hows your bass at 5 watts with an 8''?

Bass is what sucks up RMS numbers.

You can be loud without having bass.
 
To say that wattage is "overrated" is missing the point IMO. If you don't need the extra power in the first place, then you obviously won't benefit from it. That doesn't mean you can start drawing conclusions and throwing out broad generalizations though.

It's more about evaluating your usage scenario and making the determination on an individual basis as to how much power you will benefit from.

hnash53 said:
The 80dB listening level is about the max I can even handle in my typical listening position. It's more like 70dB or less most of the time.
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If you consider that loud, then you are likely spot on about having very modest power requirements. It also has a lot to do with what sort of music you listen to, if you use EQ, etc. Bass sucks up power.

My preferred listening level is significantly higher, and much of the music I enjoy is fairly bass heavy. When I had my L100Ts on my Yamaha M-2 they had no problem eating up all ~240wpc it had to give, and the most noticeable side effect when it got to that point was loss of definition in the bass. Powering those speakers now with two bridged P2201s for ~700wpc, I can play them even louder than what was possible before and each note of bass is clearly defined and hits me in the chest like a jackhammer :yes:
 
Depends if the playback level you're talking about is the peak level or the average level.

If it's peak level then the power requirement is along the lines of what you calculated. If the level is the average level then you need to figure the music's peak demands as well. A good number on average is 10dB peak to average ratio. So, if it takes 5 watts to produce the average level then with 10dB crest factor in the music, peak power requirement would be 50 watts.
 
The EPI 150s each have an 8" woofer and inverted dome tweeter. And the second pair has the same size and type of drivers. At 70dB right now the bass is pretty good (listening to Robert Miles' "Fable"). I adjust the bass knob accordingly when varying the volume. If I punch in the "loudness" button with the volume high, I can detect some clipping. But I never get close to that volume/setting when listening. At 70dB right now, it's a bit high for me.

The EPI 150s woofers can go down pretty low... 35Hz or so. The sealed speakers and the enclosures filled with acoustic batting enable these speakers to produce outstanding bass.

So, from that it seems as if the bass is good at the less than 5 watts I'm listening at right now.
 
hnash53 said:
The EPI 150s each have an 8" woofer and inverted dome tweeter. And the second pair has the same size and type of drivers. At 70dB right now the bass is pretty good (listening to Robert Miles' "Fable"). I adjust the bass knob accordingly when varying the volume. If I punch in the "loudness" button with the volume high, I can detect some clipping. But I never get close to that volume/setting when listening. At 70dB right now, it's a bit high for me.
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Are you measuring using A-scale "dBA" or C-scale "dBC"?
 
I wouldn't choose an amp because of it's low power....but I never turned up the 35 watt or 38 watt receivers past noon. I don't play the 90 watt amp currently in the rack it any louder than the lower wattage boxes.

The 35 watter is a Pioneer SX-727, completely restored by a pro, every cap & most diodes, and it has an amazing sound quality. The phono stage is really nice.
The 38 watter was a lovely Marantz 2238b, and sounded pretty darn good until it didn't.
 
Peak level? Average level? Those terms are vague to me. By "peak," do you mean when the music gets loud for a moment or two? By "average," do you mean where the music "hangs out" most of the time? If I understand these terms correctly as such, then I think the 70dB is about average, allowing another 10dB for peak.

Amazing what 5 watts can produce.
 
As for different measuring scales, I have no freaking idea. The notes for this app do not distinguish the type of scale used.
 
You should try a more powerful amp, then see what you think. Most of my listening is done at less than 1 Watt, but not all of it. I can't see myself ever having a small Wattage amp in my main system.
 
hnash53 said:
As for different measuring scales, I have no freaking idea. The notes for this app do not distinguish the type of scale used.
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Two things...

phone/tablet apps are not really that great for measuring SPL, and I've seen many that produce readings that aren't even close to accurate (off by 20+ dB). For one, different phones come with different microphones, and I'm guessing the app you are using probably wasn't specifically designed for your specific phone.

Not telling you what scale it's using is a bit obnoxious. A-scale and C-scale measurements can differ by 20+ dB in some cases. It would probably be safe to assume it's using A-scale, but you know what they say about assumptions...
 
Researching this app a bit more says that it was calibrated with a dB-A sound level meter. Reviewers of the app say that it's good up to 90-100 dB, and not accurate beyond those levels.

I'd never listen to music that loud on my home system.
 
Too much over thinking on this!
Shouldn't take to long to find out if you like it clear and louder than you already have!
As for me the more Watts that I can have under anyone's definition RMS/PMP/Whatever Scale you know,the more the better but really to each his own as always.Running Tubes at 1-2 Watts with the high efficiency speakers (98-102 DB's) is plenty loud yet not so efficient speakers (80-90 DBs) need more power period depending on how loud one likes or needs? Trail & Error?
 
I wasn't wanting to choose an amp because of its low power, but instead of paying for watts I'll never use or need, I was hoping to get better quality audio design and internal components which contribute to audio quality.

Since watts are "cheap," I'll go for a 30 WPC receiver with high quality audio components rather than a 100+ WPC monster.

And since I like the Quadravox sound from Realistic, perhaps I could get a more powerful STA receiver... 25-40 wpc.

Thanks. Any other suggestions for lower wattage/higher quality components in a receiver would be welcome.
 
I'm willing to pay more for design features/components that contribute to audio quality than I am for "wattage."

Since the wattage thing is blown way out of proportion, I want to learn about what/which kinds of components/features/specs I should be looking for. Having said that, I'll probably get comments on THD specs... but anything around or below 1% is likely indiscernable anyways. So, what else is there to consider for quality audio?
 
hnash53 said:
I wasn't wanting to choose an amp because of its low power, but instead of paying for watts I'll never use or need, I was hoping to get better quality audio design and internal components which contribute to audio quality.

Since watts are "cheap," I'll go for a 30 WPC receiver with high quality audio components rather than a 100+ WPC monster.
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Your post is contradictory. If you are looking for "better quality audio design and internal components which contribute to audio quality", a 30WPC receiver isn't where to look...
 
titanstats said:
Your post is contradictory. If you are looking for "better quality audio design and internal components which contribute to audio quality", a 30WPC receiver isn't where to look...
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Absolutely wrong. Low powered amps does not necessarily mean cheap components, in fact many times the engineers have more leeway and parts in the bins to work with. Additionally, there were companies that concentrated on higher quality lower power amps. I just finished some months, actually years, going through my inventory quite comprehensively and just decided on the final cuts. The remaining units are all lower power, nothing greater than 25 watts rms ftc. My larger and sought after units all failed in the end.

Even with tube amps it is not uncommon for a company's smaller amps are better sounding in system.

There are very few home audio speakers that actually need high power amps to open up such as the AR LST. With my system at average listening levels with my least efficient speaker I hit .0004 watts on my RS peak level meter with peaks maxing out at around .5 watts with no loss of dynamics. Using my HIIs, on peaks really pushing them where they start sounding more like a disco speaker than home audio, my peaks are less than 1.5 watts and my ears start hurting. The results were no different when I used my 200 and 105 watt amps on them.

But, if a high power amp for some reason gives you either pride or satisfaction, go for it. In the end, this hobby is as much about pride of ownership as the sound quality.
 
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Brian... your comments verify what I've thought about high audio quality and low wattage... they are NOT mutually exclusive. In other words, just having lots of watts doesn't automatically imply high audio quality.

So, after gleaning your inventory, what low wattage amps/receivers "made the cut"? I'd be curious to know.

Thanks.

Hal
 
Brian said:
Absolutely wrong. Low powered amps does necessarily mean cheap components...

But, if a high power amp for some reason gives you either pride or satisfaction, go for it.
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Gonna have to say, that's kind of an obnoxious way to end a post -- none of this has anything to do with pride. All audio, no attitude...

OP was asking about 30 Watt receivers -- not amps, not tube gear. If he thinks he's going to get better sound quality out of a company's mid line offerings than their higher-powered units, he's gonna have a bad time. That's just not how it works. If a company has gear for sale at six different price points, and the cheapest ones sound best and have better build quality, they aren't going to move many more expensive units, are they?

I have yet to come across an underpowered receiver that has better build quality, components, or sound, than the more powerful offerings -- not even one. They may exist, but they'd be exceptions to the rule.

I'd love to hear the list of 30 Watt receivers out there that are better than the same company's larger offerings -- care to share?
 
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