Is more power really needed? (1 Viewer)

[Jason.Soko]

I'm telling you right now, you do not listen much higher than 1 watt of power. Like I said before 1watt gives you that sensitivity rating. 90db is pretty damn loud.

Trust me man, we, you use far less power than you think. It is like the 20amp circuit debates I engage myself in. I'd really really really like to see a system drawing 10 amps of current in a home.

Here is some tidbits for you.

The measurement of noise (bels and decibels) is logarithmic. In other words 40 decibels is not just twice as loud as 20 decibels. And, 40 decibels is actually about nine times as loud as 20 decibels. The reason for this is that loudness increases approximately three times for every bel (or 10 decibels). So 30 decibels is three times as loud as 20 decibels. 40 decibels is three times as loud as 30 decibels. This makes 40 decibels nine times as loud as 20 decibels. You should know that loudness itself is quite subjective. What sounds twice as loud to one person may not sound twice as loud to another. To the average human ear, however, an increase of 10 decibels means that the perceivable increase in noise is triple the noise.

 

[Jason.Soko]

Here is some other useful info.

Near total silence - 0 dB
A whisper - 15 dB
Normal conversation - 60 dB
A lawnmower - 90 dB
A car horn - 110 dB
A rock concert or a jet engine - 120 dB
A gunshot or firecracker - 140 dB

 

[Wayne_T]

Mike, you get it, and you raise the appropriate question... how much difference will a small increase in power make? Given the logarithmic relationship between power and volume, it would appear that it takes significantly more power to make an audible difference. There are no absolutes, but directionally it is correct to say that more power will sound better, i.e. closer to the sound of the live performance. My experience is that 100W sounds significantly better than 60W, and that 200W sounds way better than 100W. I am now driving my mains with 313W (Bryston spec), and the difference from 200W is noticeable by anyone. And we don't listen any louder than we used to... in fact the older I get the lower the volume I seem to enjoy.

There is another question that needs to be asked... how truthful are the manufacturer's power claims? There is a site (I've lost the link) that lists the tested power outputs of many popular receivers, and it is surprising how over rated some of the manufacturer's claims are. Perhaps someone can post the link.

Jason, if you are making an argument that there is no improvement with more than 100W, with all due respect I think most audiophiles will disagree with you. I think that we often do drive our speakers with more than 1W average power, and that loud sounds are often more that 4 times as loud as average. I would contend that anyone could discern the improvement in sound of a 200W amp over a 100W amp, both playing the same material at the same volume. I'm not so sure that the 15% power difference between the receivers Mike is considering would be noticable.

 

[Jason.Soko]

For home theater I am not arguing about more power usage as the range of sounds is all over the place. But as far as normal music listening levels, honestly I do not go much over 1 watt of power unless I am cranking them. Then maybe, maybe a couple of watts. 90db is LOUD in my room.

As far as 200w sounding better over 100w, I would imagine that is merely due to the twice as much headroom. The amp is not nearly working as much as it would be with only 100w of power at it's disposal, therefore producing cleaner sound. I can't honestly believe you are using 200watts of power, but merely using a much lesser amount much more efficiently.

 

[Jason.Soko]

By the way, here is that chart.

http://www.geocities.com/Area51/Holl...1/ratevsac.htm

 

[Wayne_T]

Thanks Jason. That was the link I was referring to. Doesn't look like its been updated for a while.

Yes, I believe that I do use the power - at the peaks. And I really don't listen at very loud volumes.

I don't know that I would notice much difference on movies - do I really care if I've clipped the sound of an exposion that was likely louder than I'd want anyway?

Where the power counts, imho, is for music. That is why I only spent the extra money for the amp for the mains, and why I bought I good sub.

Wayne

 

[MikeNagy]

Wayne: I mirrored that page on my website since the original was on Yahoo! and had lots of annoying pop-up ads:
http://www.mnagy.net/ratevsac.htm
I actually hadn't looked at it in a long time, and I was going to post the link to it to show how NAD does not exagerate their power ratings (a lot of their reputation is staked on the fact that none of their ratings are exaggerated) and I was surprised to see that SR found that the 752 was outputting 92 watts/channel when it started clipping. Also the THD+n was measured lower than the spec'd 0.08% THD. Of course, these measurements should be taken with a grain of salt, because who knows what methods they used to measure these numbers, but they certainly are encouraging.

Now I'm pretty much leaning towards the T752. The good measurements on that page combined with the fact that a 50% increase in cost is not worth a marginal increase in power, especially since I don't really have any use for any of the extra features that the 762 has. And I'll have more money leftover for better food and drink. yay!

 

[Chu Gai]

When all is said and done, if for some reason the receiver doesn't meet your expectations, will you be able to return it and get your money back?

 

[Michael R Price]

90db continuous is pretty loud, and for people with inefficient speakers that can mean 5-10 watts per channel average power. To meet 105db peaks cleanly, which I think is a realistic goal, users of 85-90db efficient speakers may need 200 watts or more. This is not a good thing, but it's a tradeoff necessary to get the kind of speakers we can live with. And amplifiers distort audibly before they clip, so some might sound better than others once you start getting to, say, 20 watt peaks.

Mike, the Stratus Silver speakers are quite inefficient at 86db/2v/1m. Please keep that in mind.

For the record I did notice a significant improvement in dynamics going from a 100 watt receiverlike amp, which was actually capable of meeting its ratings, to larger DIY amps using significant power supplies.

And I know 90db is a bit loud, but sometimes it just sounds so damn good I have to turn it up even more. Keep that in mind, because if your speakers can sound good loud and your amplifier starts to wimp out, it might be disappointing.

 

[Asim]

thanks for this thread guys...really learned a lot from all of the responses!

 

[Johan_relen]

Do you all think it's possible driving fronts (91dB/1W/1m), a center (90dB/1W/1m) and surrounds (88dB/1W/1m) on a Nad T742? They're all rated 4 ohm speakers.

Or do I need the T752 (don't have the money really)?

This will be my only system so both HT and music will be played.

 

[MikeNagy]

Chu: Yes, I'd be able to return them. I'd be buying from either Yawa or DMC Electronics; both are about the same distance from me.

Michael: I know that more power is better, and I know that the PSB's are hard to drive (due to low sensativity and 4-ohm-ness), but my question was will I see a notable difference between the 230 watts dynamic of the 762 and the 200 watts dynamic of the 752?

Johan: It's POSSIBLE, and it will probably work nicely...just not optimally. But if you don't have money for the 752, then you don't have money for it. Buy only what you can "afford" (its up to you to define what afford means)

 

[Johan_relen]

Afford is a _very_ relative term I'm afraid...I have more cash but don't want to spend it. I guess I could save cash a while longer and wait for my birthday or the rumoured replacment of T752. I'll have to say what my parents say as well I guess...

 

[Carlo_M]

I agree with just about all of what's been said. I own a T762 and am very, very happy after upgrading from a Sony 555ES. They were supposedly 100wpc but I can tell you there is a big difference (and not just in my head either, but confirmed by several people in admittedly non-scientific listening tests at my house) in sound.

The most compelling reason for going with the T762 is the torroidal power supply, and the extra channel. That way you have CYA for the EX & ES DVDs. I didn't think much of it when I didn't have it, but now that I have the extra center channel in the rear it just adds that little bit of je ne sais quoi...it's just frickin' cool that's what it is.

re: the power and volume, yeah I don't listen to things louder on the T762 than on the 555ES. But it's like a 6 or 8 cylinder car vs. a 4 cylinder car. They both go 65mph but the ride difference is there between a BMW and a Corolla. Not just comfort either, but in the way the engine handles and sounds going 65mph. That's kind of what I can use as an allusion to what I'm hearing. The amp never sounds like it's straining at any reasonable output.

 

[Robert Tonkin]

Mike,

As I am going to do exactly what you are doing, using an AV receiver for HT processing duty and keeping the 2 channel music separate, I'm following this thread with great interest.

Two related questions come to mind. I hope you will allow me to pose them here as they are VERY related to the current discussion of amps in receivers.

1. Does the design of the "usual suspect" receivers, NAD Pioneer Elite, Denon" differ from one maker to the next as to how much current (if any) you would pick up in the used channels by not using others, or in Mikes case not using the center and surrounds right away? Is that current available to the other channels in the receiver by not using 3 of the 5 channels (assuming a 5 channel receiver)?? Put another way, will the ratio of available power to any channels be equal across all receivers regardless of who, or what type amp they employ? Will Mike be wasting money by having a 7 channel amp and not using two of them ever; or is that current, or some portion of it, used in PSB's for him now, and then redistributed to his next 3 channels when he uses them? Do some recievers do a better job of redistributing unused current from unused channels into channels being used?

2. Mike's PSB Silvers have a 91 db typical listening room sensitivity (from PSB website). They are 4 ohm speakers rated for 15-250w, 400 dynamic peak. Is there such a thing as "too much" power? Is anything over 400 too much? What if the magic amp fairy left a Bryston 6B SST amp under his pillow for a rotten tooth he lost from not eating because he couldn't afford food after buying his receiver: Is 500 watts too much power for his PSB's??? I know the usual caveats of room size and bleeding eardrums, but leaving all those aside, will 500 watts really make the PSB's more "transient" resilient without actually harming the coils as they have a top dynamic peak of 400 watts ??

Thanks Guys!!

Robert



stratus silvers @250

The reason more power is important is not beacause we want to play the music louder. God forbid! 25 watts average power would be unbearably loud in most rooms, but a 25 watt amp would be terribly underpowered if you wanted to listen at an average 2W with decent dynamic range. More power gives you cleaner, truer sound, not louder sound.

My advice (for what its worth)... get all the power you can afford.


The most compelling reason for going with the T762 is the torroidal power supply, and the extra channel. That way you have CYA for the EX & ES DVDs. I didn't think much of it when I didn't have it, but now that I have the extra center channel in the rear it just adds that little bit of je ne sais quoi...it's just frickin' cool that's what it is.

 

[Michael R Price]

Mike, the difference between 200 and 230 watts is completely un-noticeable, almost a rounding error as far as loudness is concerned. However, the stronger amplifier may sound a little better at normal levels, so it's a toss-up.

 

[MikeNagy]

Man...reminds me of when I was on the freeway the other day, me and this BMW was chillin' side-by-side at like 60, traffic was somewhat thick. Then an opening appears in front of the BMW, and that guy took off like he was standing still. No way could my car even come close to that! Siiigh....

 

[MikeNagy]

Err...I take that back. Apparently, the Rotel 1055 can reassign the front channel amps to the back (for if you added a power amp for your mains). So it is possible, but I've yet to hear of any that can do it the other way around. I would not be at all surprised if the Rotel can do this, too.

Should I be looking at a Rotel?? How do they do for 4-ohm loads?

 

[Carlo_M]

Then an opening appears in front of the BMW, and that guy took off like he was standing still. No way could my car even come close to that!

I was referring to sound differences between my 555ES and T762 at normal volumes, but this example is also appropriate because that "acceleration" would be analogous to what an amp has to do when a passage in a movie becomes very loud (explosions, crescendo in music, etc.). And the more powerful amps/receivers will perform more like that BMW.

RE: Rotel - I would think they would have no problem with 4 ohm loads though I'd check the website for the specific model you are interested in. BTW, Rotels had some issues IIRC but since I wasn't in the market for that brand I can't tell you what they were. Maybe a search here or at AVS would yield a result.

 

[Michael R Price]

"Then an opening appears in front of the BMW, and that guy took off like he was standing still."

Bingo! That's what happens when you have a mondo amplifier (and more importantly, mondo speakers). Instead of thinking "Ow turn it down", you think "Weeeooo... nice." Something to that effect.