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More power doesn't mean better sound...


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#1 of 22 ChrisDixon

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Posted February 23 2005 - 08:35 AM

...when there aren't other factors clouding the judgment. See my comments bellow (taken from a previous post on AVS) and let me know if you agree or not.

Quote:
I still don't undertand the mixed messages that are sent on these forums regarding amp power. On one hand, you often hear the reality that ijd said above: at very loud levels, your amp is only using 1-3 watts. On the other hand, you hear people saying that more power = better sound quality and imaging (especially with music). Break out your SPL and listen to music at 90db. I don't know about you, but I don't usually listen much louder than that, and I am generally more comforatable in the 80s for "loud" listening. So, what is it about headroom (that is almost never used) that makes a system sound better?

It's probably similar to the "all amps sound the same" argument, but if you compare apples to apples, the difference between a true 100watt amp and a true 200watt amp is probably only noticable at ear-bleeding levels, or in a cavernous room. If you are in a typical room with typical listening habits, my guess is that there may be a few seconds per week that might actually sound different - especially given the fact that your sub amp takes the most demanding job of low bass during movie passages!

The key here is "apples to apples" (amp to amp with adequate power supplies and the same pre/pro for example). I totally agree that a 200 watt separate amp sounds better than a 100 watt receiver, but the reasons for that are many. Just read any receiver vs. separates thread to see why. Am I completely off base here, or is extra "headroom" one of the more overrated priorities?

Chris

#2 of 22 Elinor

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Posted February 23 2005 - 08:53 AM

Depends on the speakers, to a degree. How difficult are they to drive?

Nice efficient 8 ohm speakers aren't going to sound much different, IMHO, with an 80 wpc amp or a 200 wpc amp of the same make. I couldn't hear a dam bit of difference with my speakers when I unplugged the 200 wpc to test a newly purchased 80 wpc.

Inefficient 4 ohm speakers ... maybe a different story.

How the system crossover is set (large vs small) is going to have an influence too ... making the speakers produce more bass puts more drain on the amp ... and a lower watt/current amp will begin to struggle under a sustained difficult load.

I don't necessarily disagree with you, I just don't think you can ever make blanket statements like that.

#3 of 22 David Judah

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Posted February 23 2005 - 09:05 AM

Quote:
Am I completely off base here, or is extra "headroom" one of the more overrated priorities?

It depends on alot of factors, as mentioned, but generalizing with the 90dB+ sensitivity, 8 ohm speakers that alot of us have, I'd say yes. In many set-ups the money could be better spent on other things in the system.

My foray into digital amps has showed me that at least for my system, my 200x5 Sunfire was overkill in all but the most extreme and rare situations. The Sunfire is now gone.

DJ

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#4 of 22 ChrisDixon

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Posted February 23 2005 - 09:12 AM

That's why I qualified it with "typical conditions". I think most people DO use a sub, at least for movies. Your point about inefficient speakers is a good one, but I think a lot of people with very efficient speakers and normal room size are paying more than they need to for amps, and manufacturers are happy to provide them. IMO, there should be more of a market for quality ~100wpc amps, but 200 seems to be the place that makes people happy (and gives them better bragging rights), so there are a lot more options.

Chris

#5 of 22 David Judah

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Posted February 23 2005 - 11:09 AM

Yeah, it seems like the ~100 wpc amps are more common in a stereo configuration. I have an Adcom at 125 wpc that I use for the sub, and it was very inexpensive but solid.
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#6 of 22 mackie

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Posted February 23 2005 - 12:33 PM

My experience has been that a 200w external amp didn't make much difference except at high volumes over the 110w per channel amp in my Denon 3803 with my Paradigm Studio 40v3. I use a sub and cross over at 80 hz. You often hear people say that adding an amp makes a huge difference. In many cases it can, but not all. I recently got a pair of swan 4.1s that I run on a Denon stereo receiver with a healthy 100w per channel output. I'm going to throw the 200w mono-blocks into the mix to see if it'll make a difference with a floor-standing speaker receiving the full signal bandwidth that based on specs isn't necessarily a easy to drive. Anyway, I kept the external amps because they give me options as far as future upgrades goPosted Image

#7 of 22 Kevin C Brown

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Posted February 23 2005 - 12:40 PM

Chris- I 110% agree with you, and I have 3 examples why:

a) Acurus 100x3 vs 200x3
b) Bryston 5b-st/8b-st vs 4b-st
c) Nakamichi PA-5AII vs PA-7AII

In each of those cases, the 2nd amp is exactly the same core design as the 1st, just more powerful. But also in each of those 3 cases, the "ear up against the tweeter" test yielded more hiss with the more powerful amp. (At various times, I had each combo on hand at one time. ... Surprised me the first time I heard that. I thought there was something "wrong" with the more powerful amp ... the 1st time.)

And to clarify now (because I've gotten into very heated arguments on AVS about why more powerful amps are not necessarily a good thing), the "ear up against the tweeter test" doesn't necessarily mean your ear actually has to be right up against the tweeter. Worst case, the hiss can be heard out to a distance of 4 ft or so. (... In my 3 cases with my electronics in my room. I do actually know people who put up with being able to hear hiss at their listening position. I don't understand that... One reason why I run with 125W/ch now... Posted Image I personally just don't need that much power.)

Also, in each and every case the s/n between the lower power and higher power amps is the same. That means that because the more powerful amp can produce a signal to a louder volume, the absolute noise level of the amp is allowed to be comensurately higher. Hence, more hiss. The absolute noise floor is higher

Now, some people do need more power. Bigger (deader) room, inefficient speakers, low impedance speakers, listening habits, etc. More power (!) to you. Posted Image But I agree that most people don't need to buy as much power as they have. And you hit the nail on the head too: since most people do crossover to a sub, less power is needed by the main power amp for the speakers themselves.

It amazes me that sometimes I get into arguments with people who believe that the more powerful amp is "better" simply because it has more power. Hogwash. If the design is the same, then there is absolutely no difference in sound quality until you begin to hit the limits of the low power amp.

Marketing being marketing though, seems like the magic number now for power amps is 200W/ch. But most people also forget about the log nature of sound, that 200W/ch only gets you 3 dB more volume than 100W. Increase the volume control on your pre/pro by 3 dB right now. Not much louder, right? Posted Image Sure, you can get benefits with transients and such, but again, only if you are reaching the limits of the lower power amp in the first place.

And, one question that I have asked in discussions like this that David, you allude to: when I look at "higher end" stereo publications, European magazines, etc, *most* amps are 100W per ch or less. And I have come across some quotes such as "the lower power amp has a better refined, more delicate soundstage." I don't 100% know the answer why that seems to hold, but I am slowly becoming convinced that mating a too powerful amp with the wrong speakers (i.e., too efficient) can muddy low level detail. And it is absolutely not that the higher power amp has more "resolving" ability either. It's just noisier.

That's what I think, anyway. Posted Image
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#8 of 22 Chu Gai

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Posted February 24 2005 - 12:22 AM

Quote:
I do actually know people who put up with being able to hear hiss at their listening position. I don't understand that... One reason why I run with 125W/ch now... I personally just don't need that much power.)

True, but part of that's a judgement call on the listener and can involve various degrees of an obsessive/compulsive disorder known as audio nervosa. If you can't hear the hiss during playback then you can argue it's really a moot point. OTOH, if any kind of hiss is going to get to you, then you'll completely sympathize with Jack Nicholson in the film, As Good As It Gets. Geez, back in the good old days, 100 wpc was looked at as overkill.

You're right about your comments regarding S/N since it's referenced to power of the amp. One other thing to consider though is that sometimes this noise that you hear is due to very slight mismatches in ground potential between your amp and preamp. One way to test this is to put a product that contains an isolation transformer that breaks the ground like from RS, EbTech, Jensen (pricey!), or others. If you now have silence, then the problem wasn't the S/N. If you now hear greater space, more palpability, greater space between the instruments, your ears have been magically transformed to gold and you can now post in Audio Asylum.

Crossovers to a sub I think is a good idea even in the cases where all you do is listen to music. It relieves the main speakers from the onus of reproducing the lowest frequencies and as you suggest, can make marginal amps or receivers completely adequate. I feel this is true even with so-called full range speakers. Due to room mode issues with low frequencies, having the mains reproduce them generally means that you'll probably have big suck-outs since their locations will fail to excite all the room modes.

Quote:
And, one question that I have asked in discussions like this that David, you allude to: when I look at "higher end" stereo publications, European magazines, etc, *most* amps are 100W per ch or less.
Yes, but there are signficant other issues at play here. Houses, apartments, and room sizes in Europe, Asia, and elsewhere are notably smaller than in the US requiring less 'oomph'. Further, the mix of speakers with sensitivities that are greater than in the US is different. It's like the size of the cars, greater number of diesel vehicles that exist in Europe due to parking limitations and fuel prices. There are signficant cultural differences that go a long way to explaining lower power amps over there.

Quote:
And I have come across some quotes such as "the lower power amp has a better refined, more delicate soundstage."
Sheesh! Can't believe everything you read now! Next thing, you'll start looking at European women with underarm and leg hair as sexy Posted Image Europeans have long turned their noses up at the colonies.

Quote:
... but I am slowly becoming convinced that mating a too powerful amp with the wrong speakers (i.e., too efficient) can muddy low level detail.
Well it makes sense to pick your speakers first and then find an amp that can drive them to the levels you want without making the amp go into distress. That might be 40, 110, 300 wpc. Also of importance is to give thought to the speaker impedance/phase angle as a function of frequency when looking to an amp.

#9 of 22 mackie

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Posted February 24 2005 - 10:52 AM

Chu - will you elaborate on

QUOTE]Also of importance is to give thought to the speaker impedance/phase angle as a function of frequency when looking to an amp.[/quote]

#10 of 22 Kevin C Brown

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Posted February 24 2005 - 12:21 PM

Chu- I agree. It is a *system* that we are dealing with. Pre/pro, cables (!), amp, cables (!), speakers. Some eqp does work better with other stuff, some doesn't. (Some high end cables introduce too much capacitance, for example.)

Since I am not being flamed here, like I was on AVS Posted Image, I actually have a working theory too.

In most cases, two amps from the same manufacturer, same design but one high power one low power, the big differences include, a) size of the transformer(s), b) number of output device, c) amount of capacitance. The higher power amp has more output devices, hence, it has a higher noise floor. (Assuming exactly the same kind of devices, just more of them.) What do you think?

Don't get me wrong, that has nothing to do with saying amp company A with 4 output devices/channel will have a lower noise floor than Amp company B with 27. Just that if they are the same maker, same design, more could be worse than less. ??
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#11 of 22 eddieZEN

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Posted February 24 2005 - 02:13 PM

Chu,

this is a little off-topic, but...

> Next thing, you'll start looking at European women with underarm and leg hair as sexy

I agree with the leg hair (if it's really visible) but beg to differ on the armpit hair---I once had the priviledge of snuggling up with a Slovak nymph during a hiking trip in my 20s who not only had unshaven armpits but also didn't use deodorant...ahhhh it was wonderful waking up in the morning with my nose buried in her armpit!

Armpit hair on a woman is intensely erotic because of the resemblance to pubic hair, especially the light musky scent of female B.O. is the best aphrodisiac on God's green earth! Who needs Viagra when you can sniff a sweaty woman's armpits (and other body cavities)?

#12 of 22 Chu Gai

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Posted February 24 2005 - 07:07 PM

I'll dig up an article that gets into that mackie, just bear with me.
Quote:
What do you think?
I just think some amps, even within the same line, can have the same or different S/N. Damned if I know the reason why or what it's specifically related to. I do though, think it's funny when people buy 200+ wpc amps to drive high efficiency horns. Really, how much do the ears have to bleed?

Damn eddieZen. Even asian women are known for some of that.

Posted Image

#13 of 22 mackie

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Posted February 24 2005 - 11:06 PM

Thanks Chu - I'm trying to think of something witty to write about that picture, but I can't get the mental picture of me swinging from those handlebars out of my mindPosted Image

#14 of 22 dany

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Posted February 25 2005 - 02:15 AM

Nice grass.
Get In My Belly.

#15 of 22 ChrisDixon

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Posted February 25 2005 - 04:49 AM

I posted this thread, and then got too busy to keep up with it. Imagine my surprise when I see that it is now about armpit hair!

I hadn't even considered the extra hiss thing, though I tend to agree that it's not really an issue if it's only audible when "ear to tweeter". Also, from what I've read, speakers can suffer from dynamic compression when high spikes of power are sent from a beefy amp anyway.

Someone mentioned that 100wpc is more common in stereo amps, which is interesting given the fact that more speakers give you additional spl due to sonic reinforcement. That is, you need LESS power in a multi-channel amp. Using an spl calculator (http://www.myhomethe....alculator.html) I calculated the max spl for a 100x5 system, and it came out to 110.3. For two channel, it came to 106.3.

The analogy I like to use is that I bought a car with a v6 so I could have more power at all speeds. I wouldn't have done that if it only provided more acceleration between 110 and 113 mph (in typical driving conditions).

Chris

#16 of 22 dany

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Posted February 25 2005 - 05:27 AM

Watts sell rather you need them or not.
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#17 of 22 Arthur S

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Posted February 25 2005 - 05:41 AM

Elinor hit the nail on the head. If you have your speakers set to small and bass below 80Hz is being handled by a subwoofer, a big amp is rarely going to make much of a difference.

If on the other hand you run your speakers full range AND you boost the bass either with the tone controls or any kind of EQ, a big amp will eliminate potentially audible distortion.

Bass is what creates the need for high power. That's why subwoofer amps run 300-1,250 watts.

#18 of 22 John Garcia

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Posted February 25 2005 - 07:59 AM

Chu always has to take it one step further...LOL

I have to agree with Kevin - unless the amp is struggling to reproduce what you want at a given listening level, an amp isn't going to make your speakers sound like new speakers. In my case, with 4 Ohm speakers, the difference was quite noticable when I moved to monoblocks for my mains. My receiver didn't like driving that many 4 Ohm speakers.
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#19 of 22 eddieZEN

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Posted February 25 2005 - 07:59 AM

Chu,

ooooh, can I have her phone number? Posted Image

#20 of 22 John S

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Posted February 25 2005 - 08:23 AM

My theory is that you can never have to much power. Period.

And maybe with the turn of the thread. Any love is good love'n???


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