Amplifiers affecting speaker frequency response - Page 4 - AVS Forum
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post #91 of 362 Old 11-11-2013, 10:25 PM
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Originally Posted by Wayne Highwood View Post

The only Krell I've seen personally had an overblown fully regulated power supply, more complex than some entire amplifiers. It was stable and doubled down almost to a dead short. This was some time ago, perhaps they've changed their approach in recent years (it sure would make economic sense, and who really needs an amp that can double as an arc welder?), I just don't know, but in that particular case it was not playing with the numbers but over-engineering to the power supply that did it.

Speaking of arc welding, does anyone remember an amplifier test years ago (I think is was in Stereo Review) where the reviewer found that the output voltage was high enough to strike an arc and the amplifier could drive a load down to a fraction of an ohm - so he decided to use a test tone and struck an arc between two pieces of metal which actually created a pool of molten metal vibrating very loudly at the test tone frequency? I don't remember all the details. Talk about ridiculous output current capabilities - I can't imagine any kind of speaker that would require even a tenth of that kind of power even at deafening levels.

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post #92 of 362 Old 11-12-2013, 06:16 AM
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Originally Posted by mtn-tech View Post

Speaking of arc welding, does anyone remember an amplifier test years ago (I think is was in Stereo Review) where the reviewer found that the output voltage was high enough to strike an arc and the amplifier could drive a load down to a fraction of an ohm - so he decided to use a test tone and struck an arc between two pieces of metal which actually created a pool of molten metal vibrating very loudly at the test tone frequency? I don't remember all the details. Talk about ridiculous output current capabilities - I can't imagine any kind of speaker that would require even a tenth of that kind of power even at deafening levels.

I'm not a welder or welding engineer but its quite clear that arc welding is theoretically within the capabilities of some power amps used for professional audio.

Arc welding usually involves 40-60 volts or so, at 60-150 amps. The upper numbers multiply out to 9000 watts, which is still less than the largest amps use for pro audio which run well beyond 10 KW. An arc welder usually puts an inductor in series to support striking and pulling the arc.
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post #93 of 362 Old 11-12-2013, 08:12 AM
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It was a popular demo in the 80's IIRC. I think Krell started it, but I saw it done on most of the high-end amps of the day (Krell, ML, that New Zealand amp (Perraux?), PL, Threshold, etc.), with some "interesting" results at times. smile.gif The demo would kick the protection circuits on a lot of amps, leading some dealers to defeat it and try it anyway, then discovering abuse voids the warranty...

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post #94 of 362 Old 11-12-2013, 10:28 AM - Thread Starter
 
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Just a question to those more knowledgeable. If you need 50 watts to reach a given SPL, would it not be a good idea to have a 100-150 watt amplifier to keep distortion low enough?

 

So a 200 watt amplifier using 100 watts will be cleaner than a 100 watt amplifier going full out?

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post #95 of 362 Old 11-12-2013, 11:26 AM
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Originally Posted by Shaun B View Post

Just a question to those more knowledgeable. If you need 50 watts to reach a given SPL, would it not be a good idea to have a 100-150 watt amplifier to keep distortion low enough?

Keep in mind that this only concerns adequate power to avoid clipping distortion, not how the amps behave within their rated power limits (within which the differences should be inaudible for any respectable amps). That being said, sure, it's a good idea. Given that amp power is a cheap commodity, and the rapidly rising demand for power as the spl goes up, and that you ideally never want your amp to clip, then yes. The 100-150 w amps would provide an additional 3-~4db than the 50 w amp. Depending on your listening habits, that could be the difference between audible clipping with the small amp vs. no clipping or only lopping off the top of the occasional transient peak, which you may never notice. It all depends on your speaker sensitivity, number of speakers, distance, desired spl, room gain, etc. to get an idea of power requirements. You should play around with one of the several spl/power calculators available on the interwebs, just to plug in some numbers to help you wrap your head around this. There is one at hometheatershack, one from JBL/harmon, probably others.
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So a 200 watt amplifier using 100 watts will be cleaner than a 100 watt amplifier going full out?

That depends. Assuming similar distortion and noise at 100w, if you never use more than 100w then the small amp gives up nothing to the large amp. If your listening habits/room demand more power, and you speakers can take the flogging, then the more powerful amp is warranted. Or more sensitive speakers.
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post #96 of 362 Old 11-12-2013, 11:32 AM
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If you need 50 watts to reach a given SPL, would it not be a good idea to have a 100-150 watt amplifier to keep distortion low enough?
If all you need is 50w, any amp that can deliver 50w cleanly will sound as good as any amp that can deliver more than 50w cleanly.
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So a 200 watt amplifier using 100 watts will be cleaner than a 100 watt amplifier going full out?
First, it's not necessarily the case that a 200w amp putting out 100w will be cleaner than a 100w amp doing so. Depends on the amps.

Second and more important, distortion in both amps will be so low as to be inaudible. One amp might spec a little better, but you won't be able to hear the difference.

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post #97 of 362 Old 11-12-2013, 11:51 AM - Thread Starter
 
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If all you need is 50w, any amp that can deliver 50w cleanly will sound as good as any amp that can deliver more than 50w cleanly.

Why? Distortion would be lower, surely?

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post #98 of 362 Old 11-12-2013, 12:13 PM
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If all you need is 50w, any amp that can deliver 50w cleanly will sound as good as any amp that can deliver more than 50w cleanly.
Why? Distortion would be lower, surely?
It might be lower; it might be higher. Some amps have higher distortion than other amps. It's quite possible for a 50w amp to have lower distortion through its operating range than a 100w amp. If you look at enough amp measurements, I'm sure you'll find examples.

The reason they'll sound equally good is that both amps would be operating cleanly, and that means that both are producing only inaudible levels of distortion. If neither amp produces audible distortion, both will sound the same.

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post #99 of 362 Old 11-12-2013, 12:54 PM
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Originally Posted by mcnarus View Post

It might be lower; it might be higher. Some amps have higher distortion than other amps. It's quite possible for a 50w amp to have lower distortion through its operating range than a 100w amp. If you look at enough amp measurements, I'm sure you'll find examples.

The reason they'll sound equally good is that both amps would be operating cleanly, and that means that both are producing only inaudible levels of distortion. If neither amp produces audible distortion, both will sound the same.
+1

Power, if rated in a meaningful way at all, will be specified as "X watts at Y THD [total harmonic distortion]." If a 100 watt amp is rated at 1% distortion (invisible except maybe to well trained on an oscilloscope, might or might not be audible, depending on signal and circumstances) an amp rated at 50 watts with 0.5 or 0.1 percent THD could well be cleaner at 50 watts than the 100 watt amp. Both should be audibly clean.
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post #100 of 362 Old 11-12-2013, 10:27 PM - Thread Starter
 
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with a 90 dB sensitivity, at 400 watts the speakers will be putting out 116 dB each (assuming no compression, which is probably unrealistic).  Very very loud. at 90 dB, the speakers will be consuming a watt.  One watt.  If the entire sound were centered at a point where the impedance was 4 ohms, then 2 watts.  2 watts.  See, the amp will provide the voltage that its gain requires it to supply, and the current requirements will be defined by the speaker's impedance, and total power will be physically restrained by the laws of the universe we live in.  IOW, when you're listening at loud levels and using a watt or two or even five, having a 400 watt amp cannot change the power used because the way our universe works, ohm's law controls total power.

 

Just a question.

 

If I have a speaker that requires 40 watts (8 ohm) to hit 90 dB, and there is an impedance dip to 4 ohm, and music has frequencies that target this 4 ohm dip, then will my power need to double? So 80 watts? Reason I ask is because you say so above, but my question is, wouldn't that depend on how much energy is recorded? Or does it not matter? So if 4 ohm dips, and program material doesn't have much energy down at frequencies where the dip is low, then you won't need exactly double the power?

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post #101 of 362 Old 11-12-2013, 10:43 PM
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Assuming your 90dB at 40 watts is at measured in the same way as sensitivy ratings (1w/8ohm/1m), the sensitivity rating for that speaker is approx 75dB? (40w/90dB, 20w/87dB, 10w/84dB, 5w/81dB, 2.5w/78dB and 1.25w 75dB). That's a very low sensitivity rating, what speaker is that? It will take what it needs from the amp and many amps can deliver 80w at 4ohms so your amp needs to be example specific, like your speakers. Program material level could have an effect but that assumes your gain structure is already optimized, too, which it may not be. You might want to review Ohm's law for a relationship between impedance and wattage.

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post #102 of 362 Old 11-12-2013, 10:45 PM
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Originally Posted by Shaun B View Post

Just a question to those more knowledgeable. If you need 50 watts to reach a given SPL, would it not be a good idea to have a 100-150 watt amplifier to keep distortion low enough?

The distortion may not be lower on one amp vs another, even if it is running at half its capability and that level of distortion probably won't be audible. But if the amp clips, its distortion will be much higher and it probably will be audible. So the only thing you should really be worrying about is how much power you will need to drive your speakers to the volume you want - use an SPL calculator to estimate the power you'll need:

http://myhometheater.homestead.com/splcalculator.html

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post #103 of 362 Old 11-13-2013, 12:19 AM - Thread Starter
 
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[quote="lovinthehd"]Assuming your 90dB at 40 watts is at measured in the same way as sensitivy ratings (1w/8ohm/1m), the sensitivity rating for that speaker is approx 75dB?  (40w/90dB, 20w/87dB, 10w/84dB, 5w/81dB, 2.5w/78dB and 1.25w 75dB).   That's a very low sensitivity rating, what speaker is that?  It will take what it needs from the amp and many amps can deliver 80w at 4ohms so your amp needs to be example specific, like your speakers.  Program material level could have an effect but that assumes your gain structure is already optimized, too, which it may not be.  You might want to review Ohm's law for a relationship between impedance and wattage.[/quote]

 

Perhaps you misunderstood. If I NEED 40 watts to hit 90  dB in my room, at a given distance, and the impedance dips to 4 ohms at some frequency, then if music has frequencies that dip down to those frequencies, will my power need to double? I know power doubles with halving of impedance, but if the source material has very little energy at frequencies where the impedance is at a minimum then would I still need double the power at those frequencies?

This is just an example,I just want to know I'm on the same page.

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post #104 of 362 Old 11-13-2013, 12:50 AM
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What's to misunderstand? You understand that if your impedance drops from 8 to 4 ohms then by definition the wattage doubles; your amp either can provide the necessary power within acceptable distortion limits or it can't. You seem to be trying to engineer an example but aren't quite getting to where you want it to go....for example, are you talking about an average or peak spl of 90db? Or both?

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post #105 of 362 Old 11-13-2013, 02:33 AM - Thread Starter
 
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Originally Posted by lovinthehd View Post

What's to misunderstand? You understand that if your impedance drops from 8 to 4 ohms then by definition the wattage doubles; your amp either can provide the necessary power within acceptable distortion limits or it can't. You seem to be trying to engineer an example but aren't quite getting to where you want it to go....for example, are you talking about an average or peak spl of 90db? Or both?

 

But I heard from some people that if energy exists in program material that has frequencies that dip down to where the impedance dips, it isn't necessarily problematic because it depends how much energy exists at those frequencies and the duration of the signal.

 

So it got me thinking a bit - if frequencies in music matched the impedance dips of the speaker, like from 8 to 4 ohms, would power absolutely double under all circumstances, or only under certain circumstances?

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post #106 of 362 Old 11-13-2013, 02:57 AM
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By definition if the impedance changes so does the wattage....they go hand in hand; each speaker will change in impedance/wattage depending on frequency response required. I still think you have a concept/concern you're not getting across so far....

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post #107 of 362 Old 11-13-2013, 04:37 AM
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Originally Posted by Shaun B View Post

So it got me thinking a bit - if frequencies in music matched the impedance dips of the speaker, like from 8 to 4 ohms, would power absolutely double under all circumstances, or only under certain circumstances?

It could, and if the sky falls we all die. ;-)
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post #108 of 362 Old 11-13-2013, 08:26 AM
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Only one of the glaring errors above is the claim that square waves are transients. They are in fact steady state collections of sine waves. That's engineering 201 in many good Universities.
Best not skip engineering 101 though. biggrin.gif That is where they teach rc time constants and such. Rise time is a measure of *time domain* response of a system, not frequency domain. Square wave has a sharp leading edge that forces the amp to climb up its maximum level as fast as it can to track that difficult signal. By examining that signal visually or with (visual) measurement, you can get a quick idea of the rise time. This is routine in digital systems. Here is quick pictorial definition of it:

z_clock.gif

The reason square wave is used instead of a single impulse is that the square wave keeps repeating so you can use any analog scope to view it. With a single digital event you need to capture that and go back in time to look at the transient response. Today, you can get pretty cheap digital scopes that can do that but this was not the case in the past.

But let's say we use a single impulse to measure the rise time. An impulse by definition is also a collection of sine waves just the same. To reproduce an infinitely fast rise time, you need infinite number of frequency components. You would have to break Fourier and a bunch of other basic physics principals and university teaching to improvise a test signal that is a transient but has a single frequency. A single sine wave gently moves up and down and cannot possibly show you the systems rise time or transient response.

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post #109 of 362 Old 11-13-2013, 12:15 PM
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Hmmm... Rise/fall time is related to bandwidth, as is the flat top response (LF cut-off for the latter). For a first-order system (which I freely admit almost no speaker or amp really fits) the relationship is risetime = 0.35 / BW where BW is the upper frequency -3 dB point. A single tone high enough in frequency will allow you to infer risetime since the amp won't be able to follow the sine wave's slew rate. A swept sine test provides information about bandwidth, though I would use a VNA. Even ancient analog scopes had a trigger level that would allow you to capture a single event, but you had to have the right phosphor to retain the image long even to view. Delay lines even let analog scopes provide pre-trigger info.

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post #110 of 362 Old 11-13-2013, 04:27 PM
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Swept sines especially the log variety can be used to implement a Dirac Delta (Impulse) response. Indeed that is what REW uses to generate its Impulse Response and ETC. But as with the true impulse or square wave, we now have a group of frequencies we are using and not just a single tone. It simply is a more pragmatic way of generating an impulse.

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post #111 of 362 Old 11-13-2013, 04:40 PM
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Originally Posted by amirm View Post

Swept sines especially the log variety can be used to implement a Dirac Delta (Impulse) response. Indeed that is what REW uses to generate its Impulse Response and ETC. But as with the true impulse or square wave, we now have a group of frequencies we are using and not just a single tone. It simply is a more pragmatic way of generating an impulse.

The false claim that seems to be made above is that a square wave has the same frequencies in it as a swept sine or impulse(s), The square wave does not contain a continuous range of frequencies, it only contains the odd harmonics. The impulse and the swept sine contain a continuous range of frequencies. Thus testing with a square wave has inherent blind spots composed of the frequencies that it does not contain.

In another post I showed that a wide range of published audio tests simply ignore square wave testing. One reason for this is the fact that there are simply better ways to accomplish the same outcome.
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post #112 of 362 Old 11-13-2013, 09:41 PM
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Originally Posted by Shaun B View Post

Just a question.

If I have a speaker that requires 40 watts (8 ohm) to hit 90 dB, and there is an impedance dip to 4 ohm, and music has frequencies that target this 4 ohm dip, then will my power need to double? So 80 watts? Reason I ask is because you say so above, but my question is, wouldn't that depend on how much energy is recorded? Or does it not matter? So if 4 ohm dips, and program material doesn't have much energy down at frequencies where the dip is low, then you won't need exactly double the power?

For explanation purposes let's say all the frequencies are recorded at the exact same level and you set the volume control so the amplifier is outputting 2.83v.
When a frequency is produced in the speakers 8 ohm band there will be 0.35A.
When a frequency is produced in the speakers 4 ohm band the current will bee 0.70A.
With real world music the amplitude (loudness of the various instruments and voices) and frequency varies continuously but the principle I described remains the same. For any given voltage the current into 4 ohms is double compared to the same voltage applied to 8 ohms.
If the frequencies in the speakers 4 ohm band are quieter (have less energy) they will require less current because the output voltage of the amplifier will be lower.

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post #113 of 362 Old 11-14-2013, 01:46 AM - Thread Starter
 
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If the frequencies in the speakers 4 ohm band are quieter (have less energy) they will require less current because the output voltage of the amplifier will be lower.

That is what I was thinking. So then you don't necessarily need an amplifier that can double down from 8 ohms to 4 ohms. If the energy in music is constantly changing depending on the frequency and amplitude, and you need X power in 8 ohms, then you don't need double that into 4 ohms, necessarily. Am I understanding this correctly?

 

If the signal amplitude was identical for all frequencies in music then I can understand that doubling down in power would make sense.

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post #114 of 362 Old 11-14-2013, 01:48 AM - Thread Starter
 
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Also, how does the phase of the impedance affect things? I see measurements from Stereophile have some speakers have a difficult phase angles. What is that, and why is it difficult for amplifiers? The B&W 800 review shows measurements down to 3 ohms or so, across a given range, but the reviewer states that the phase angle can be very strenuous on amplifiers.

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post #115 of 362 Old 11-14-2013, 02:49 AM - Thread Starter
 
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Originally Posted by mcnarus View Post


It might be lower; it might be higher. Some amps have higher distortion than other amps. It's quite possible for a 50w amp to have lower distortion through its operating range than a 100w amp. If you look at enough amp measurements, I'm sure you'll find examples.

The reason they'll sound equally good is that both amps would be operating cleanly, and that means that both are producing only inaudible levels of distortion. If neither amp produces audible distortion, both will sound the same.


So you are saying a receiver can sound just as musical as a dedicated two channel amplifier if both are not running into audible distortion? So a Mcintosh or Krell or Mark Levinson are just the same as a Sony, or Pioneer, or Onkyo?

 

I believe products are manufactured to achieve a price/performance point. An AVR is a complex multifunctional device that does many things well without doing anything exceptionally well. To achieve maximum technological benefits costs have to be cut somewhere. It may be in finish or function or power. The technology chips cost are a dime a dozen, especially in the quantities they buy them. What pushes up costs are licensing, new product implementation and beefy power supplies with suitable output. You can guess where the costs are cut to achieve a price point of a product.

 

A power amp is just that. A one function device that is designed to achieve a desired outcome. Once again at a price point. It achieves its so called spec being a dedicated device.

An AVR in my opinion is a less discerning device. It is multifunctional and it uses multiple loudspeakers with a subwoofer to achieve "spectrum" balance. It is not optimised for pure stereo listening, that's why they have bass management and use a subwoofer to achieve that. It is tailored to sound field processing and multiple loudspeakers at the same time.

 

So I don't know how people can say that receivers can sound the same as any other amp if they are not distorting.

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post #116 of 362 Old 11-14-2013, 04:14 AM
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Originally Posted by mcnarus View Post

It might be lower; it might be higher. Some amps have higher distortion than other amps. It's quite possible for a 50w amp to have lower distortion through its operating range than a 100w amp. If you look at enough amp measurements, I'm sure you'll find examples.

The reason they'll sound equally good is that both amps would be operating cleanly, and that means that both are producing only inaudible levels of distortion. If neither amp produces audible distortion, both will sound the same.

Agreed.
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So you are saying a receiver can sound just as musical as a dedicated two channel amplifier if both are not running into audible distortion? So a Mcintosh or Krell or Mark Levinson are just the same as a Sony, or Pioneer, or Onkyo?

They are not just the same but they are enough the same that they won't sound different. Human hearing is not perfect, and many small differences will always escape its notice for all people. I make this point to head off the next claim.
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I believe products are manufactured to achieve a price/performance point.

That is true.

However, the cost of providing high performance has fallen dramatically over the past 50 or more years.

I can show you technical test after technical test where an AVR equals or beats the technical performance of high priced separates. It is all about improved general price performance, economies of scale and diminishing returns.

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An AVR is a complex multifunctional device that does many things well without doing anything exceptionally well.

In 2013 there is no need for exceptional technical performance to obtain exeptional audible performance. In 1955 a power amplifier with less than 1% THD 20-20 KHz at 20 watts was exceptional, if it existed at all. Today that's worse performance than provided by a $200 HTIB.
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To achieve maximum technological benefits costs have to be cut somewhere.

First off, we don't need maximum technological benefits. This would only be true if human hearing was ideal and perfect, which it is not. Secondly, the electronics in a good audio system do not set the technological limits. The speakers and the room set those limits.
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It may be in finish or function or power.

You seem to be willing to complete disregard the concepts of diminishing returns and economies of scale. IMO, not the best idea!
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The technology chips cost are a dime a dozen, especially in the quantities they buy them.

Well, a dollar or a few dollars.
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What pushes up costs are licensing,

It has been documented elsewhere that the licensing costs for a surround processor are the same whether the processor costs $200 or $20,000. There are also economies of scale there, that favor volume producers.
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new product implementation and beefy power supplies with suitable output.

Development costs for an AVR are about the same whether the price point is $500 or $15,000. The $500 processor sells thousands of units and the $15,000 process sells just a few. The development costs are divided by the size of the production run. the cost per unit for development of the $500 processor is far less.
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You can guess where the costs are cut to achieve a price point of a product.

I don't have to guess - the arithmetic presented above are irrefutable and demolish your argument.
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A power amp is just that. A one function device that is designed to achieve a desired outcome. Once again at a price point. It achieves its so called spec being a dedicated device.

I think that is has been shown that by ignoring economies of scale and the law of diminishing returns, your argument has become highly incomplete and grotesquely flawed.
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An AVR in my opinion is a less discerning device.

Yup, your opinion, and it has been shown that your opinion is not well-grounded in well-known facts.
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It is multifunctional and it uses multiple loudspeakers with a subwoofer to achieve "spectrum" balance.

On the one hand we have a 7.1 AVR and on the other hand we have a 7 channel power amplifier that is made by say, MacIntosh. If there are multichannel cooties as you seem to suggest, how does the MacIntosh avoid them?

On the one hand we have a 7.1 AVR and on the other hand we have a 7 channel surround processor that is made by say, MacIntosh. If there are multichannel cooties as you seem to suggest, how does the MacIntosh avoid them?
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It is not optimised for pure stereo listening,

That would be an unsupported assertion at this point. This seems to be a repeated flaw in your presentation - you seem to keep saying it has to be worse, facts be damned, just because I say so. Can we see your membership card in the association of ruling dieties? ;-)
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that's why they have bass management and use a subwoofer to achieve that.

Your challenge for the day is to find a so-called full range speaker that reproduces deep bass as well as say a $2,000 subwoofer from one of the top supplies, say Rhythmic, SVS or Hsu. I'll save you some time, we've already checked out several $20,000+ a pair high end speakers and they have come up short. Beyond that we have plenty of technical evidence that there are sound quality advantages from being able to place the subwoofer ideally and no exactly co-located with the L&R mains. You seem to be unaware of this, and are probably unknowingly discrediting yourself in the eyes of many readers.
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It is tailored to sound field processing and multiple loudspeakers at the same time.

It is well known that if you take a good AVR and configure it for 2.0, 2.1, 3.0 or 3.1 speakers it sounds great.

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So I don't know how people can say that receivers can sound the same as any other amp if they are not distorting.

It appears that there is a great deal of knowledge about audio that would alleviate your situation were you to educate yourself about them. Simple things like the superiority of dedicated subwoofers over so-called full range speakers.
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post #117 of 362 Old 11-14-2013, 04:31 AM - Thread Starter
 
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Arnyk, I'm not going to argue the point further. I don't have the technical chops to sustain an argument with you on this, I'm only going with my experiences. You explained yourself very well.

 

However this point :

 

Quote:
I can show you technical test after technical test where an AVR equals or beats the technical performance of high priced separates. It is all about improved general price performance, economies of scale and diminishing returns.


I would appreciate it if you could show me some technical tests where a modern AVR can outperform a modern processor from a high-end brand.

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post #118 of 362 Old 11-14-2013, 04:42 AM
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Originally Posted by Shaun B View Post
 

So you are saying a receiver can sound just as musical as a dedicated two channel amplifier if both are not running into audible distortion? So a Mcintosh or Krell or Mark Levinson are just the same as a Sony, or Pioneer, or Onkyo?

 

 

Arny has so completely demolished the points you made that it is barely worth responding, but I would add that your remark that some amps can sound 'musical' and others, by implication, do not, is strange and seems to be at odds with the general understanding of what an amplifier does.

 

A good amplifier does not 'sound musical' or indeed 'sound' anything. All that a good amplifier does is take the input signal and pass it out unchanged, other than in amplitude. Decent modern SS amps have been able to achieve this for decades. By 'decent' I mean the sort of amps that are found in any AVF made by a mainstream manufacturer such as those you mention. It is for this reason that in properly conducted blind tests where amplifier A is tested against amplifier B, nobody can reliably distinguish A from B. This has been proved so many times that to disconcur with these findings is pointless.

 

Indeed, if an amplifier did have a 'sound' of its own then that means that it is deliberately distorting the input signal prior to outputting it. This of course, is possible and one can, therefore, make a modern SS amp which 'sounds' like a tube amp from the 50s. But nobody can surely question that if the amplifier output signal is different from the input signal (other than in amplitude obviously) then the amplifier is deliberately introducing a form of distortion. Is that what you want from an amp, or do you want the source faithfully reproduced?

 

As Arny says, there are many measurable differences between one amp and another. But that isn't really the issue we need to address. The real issue is whether these differences are audible, and the answer is 'no they are not', hence the inability of people in the blind tests I mentioned to be able to differentiate A from B with any more reliability than random chance ('guessing'). 

 

Your apparent disparaging of the use of a subwoofer is also strange. As Arny says, nobody has yet been able to design a so-called 'full range' speaker in which the bass performance exceeds that of a good subwoofer. Considering that a subwoofer uses its own amplification (sometimes as much as 2 or 3000 watts of it) and has been designed with only one purpose in mind - the reproduction of frequencies from 20Hz (or below sometimes) to around 100-150Hz - this does not seem surprising. Just as importantly, by separating the reproduction of bass frequencies from the rest of the spectrum, the subwoofer can be positioned at the optimal place in the room for the reproduction of bass - the place where it is the least affected by room modes. This optimal placement is rarely at the same spot that the main speakers are located - which have to be, of course, located at the front of the soundstage for imaging reasons. And since almost nobody can localise bass below 80Hz, the sub is free to be placed optimally, anywhere in the room. There is no good reason not to use a subwoofer, but there are many good reasons to use one. 

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post #119 of 362 Old 11-14-2013, 04:49 AM
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Originally Posted by Shaun B View Post

Arnyk, I'm not going to argue the point further. I don't have the technical chops to sustain an argument with you on this, I'm only going with my experiences.

The tyrrany of reaching far-reaching conclusions based on sighted evaluations, eh? ;-)
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You explained yourself very well.

Thank you. I simply stand on the shoulders of giants who went before me.
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However this point :
Quote:
I can show you technical test after technical test where an AVR equals or beats the technical performance of high priced separates. It is all about improved general price performance, economies of scale and diminishing returns.


I would appreciate it if you could show me some technical tests where a modern AVR can outperform a modern processor from a high-end brand.

You are making my job extra tough by misquoting me. I said "equals or outperforms" I therefore reject your request as written.

Instead I will provide documentation of a situation where a high end processor was a mid-fi processor: This clearly supports my claim of "equals".

http://www.slashgear.com/lexicon-bd-30-reviewed-an-oppo-bdp-83-at-7x-the-price-1870267/

"Lexicon BD-30 reviewed: an Oppo BDP-83 at 7x the price."

http://gizmodo.com/5450893/lexicon-charges-3500-for-a-repackaged-500-oppo-blu+ray-player

"Lexicon Charges $3500 For a Repackaged $500 Oppo Blu-ray Player"

http://www.avsforum.com/t/1217550/hilarious-must-read-oppo-on-the-inside-lexicon-on-the-outside/150

"Hilarious Must Read - Oppo on the Inside, Lexicon on the Outside"

The device in question is a digital music player with processors sufficient to produce analog multichannel outputs, so it is in fact a surround processor.

Due to the costs of licensing the necessary decoder software and the complexity of developing player hardware there have been numerous examples of high end players and processors that share major components with or just put a high end veneer on a device that is sold in the upper-mid-fi market.

Just in the past week I documented an example of a high end integrated amplifier that appears to share critical components with a $79 stereo receiver.

And just for grins, compare these two pages:

http://www.soundandvision.com/content/arcam-avr360-av-receiver-ht-labs-measures ($1,795)

http://www.soundandvision.com/content/denon-avr-2313ci-av-receiver-ht-labs-measures ($554)
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Development costs for an AVR are about the same whether the price point is $500 or $15,000. The $500 processor sells thousands of units and the $15,000 process sells just a few. The development costs are divided by the size of the production run. the cost per unit for development of the $500 processor is far less
 
How do you know this?
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