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Emotiva XPR-1 vs Bryston 28B SST2 anyone ever compare these? - Page 2

post #31 of 48
Quote:
Originally Posted by commsysman View Post

Virtually every S/S amplifier has a flat frequency response when tested with a RESISTOR for a load. That is like testing a car on a dynamometer and claiming you know everything there is to know about that car from that one test.

If you had any experience in audio engineering, you would be very much aware that a SPEAKER is a complex load that has substantial amounts of inductive or capacitive reactance, and an impedance that is NOT linear.

The ability of an amplifier to drive that sort of load is a whole different thing, and requires a lot of attention to power supply design and amplifier design to prevent distortion.

ANY engineer that has EVER designed an amplifier KNOWS exactly what I am talking about, and your repeated statements indicating your complete ignorance of these BASIC design and performance issues serves no purpose. I don't know who "those people" are, but they sure as hell are not competent amplifier design engineers!!!

The most expensive amplifier is not always the best amplifier, but the design decisions required to make a relatively cheap amplifier pretty much guarantee poor performance in the real world (driving REAL speaker systems).

Well, I see that Arny and others have already addressed what you stated above, but I couldn't help but notice how you had no comment about the following. I don't know why you chose not to address this (I have my own viewpoints as to why, but I'll allow you to comment);
Quote:
"Could you demonstrate this in a DBT ABX test? And, yes, I mean a real DBT ABX test. You seem to suggest that this is the case, when you say that "virtually ANYONE" can tell the difference.

So it should be obvious, right? If it's that obvious - any test should show that? If I am wrong - in what way am I wrong?

Do you know that this has been done before? And if so, do you know what the results were?"

So, Commysman, if "virtually anyone" (trained or untrained listeners) can hear the difference, why haven't they been able to? Should be pretty obvious to prove in any kind of a test, right - if it's as obvious as you claim it is?
Edited by bo130 - 7/4/13 at 12:54pm
post #32 of 48
Quote:
Originally Posted by commsysman View Post

It is actually fairly simple to connect an actual speaker system to an actual amplifier, and using a signal generator as a source, measure the frequency response and distortion of the amplifier with that load over the audio band with an oscilloscope and Distortion Analyzer.

John Atkinson does a distortion analysis for every amplifier that is reviewed in the magazine Stereophile and publishes the detailed results. Since a good distortion analyzer costs $30K and more, and requires considerable expertise and experience to use properly, it is not surprising that magazines do not usually do this. He points out the shortcomings of each amplifier, and the wise will do well to heed his analysis before purchasing an amplifier.

You would probably learn a lot if you were to read 10 or 20 of his amplifier test reports from past issues COMPLETELY AND CAREFULLY and let the information sink in a bit. It is obvious that you have never done so in the past. Educate yourself a bit and your questions and statements will possibly make more sense. I am always amused when people criticize Stereophile as being a purely subjective magazine, when they do much more objective scientific performance testing of products than any other. They obviously are not reading the whole article.

This is how amplifier design engineers do it, and if you were to do so you would find that the differences between amplifiers are quite significant and measureable.

Using the complex load of an actual speaker to test the amplifier will reveal the shortcomings of the amplifier very quickly, while a test with a resistive load will only give some information.

The amplifier performance will be different with every speaker, since some speakers have a greater degree of impedance variation and reactances than others.

Better-designed amplifiers, however, will perform better, maintaining more linear gain and producing less distortion, even with those speakers that are a more difficult load to drive.

Now that's exactly what I was hoping for. Your combination of arrogant, condescending tone, along with your poor understanding of what you blather about, is precisely what makes your posts so comical. Stephen Colbert would be proud. biggrin.gif
post #33 of 48
Quote:
Originally Posted by commsysman View Post

The most expensive amplifier is not always the best amplifier, but the design decisions required to make a relatively cheap amplifier pretty much guarantee poor performance in the real world (driving REAL speaker systems).
Quote:
Originally Posted by commsysman View Post

Better-designed amplifiers, however, will perform better, maintaining more linear gain and producing less distortion, even with those speakers that are a more difficult load to drive.

What is your recommendation as to a starting price point for a better-designed amplifier?
post #34 of 48
Quote:
Originally Posted by A9X-308 View Post

Quote:
Originally Posted by commsysman View Post

It is actually fairly simple to connect an actual speaker system to an actual amplifier, and using a signal generator as a source, measure the frequency response and distortion of the amplifier with that load over the audio band with an oscilloscope and Distortion Analyzer.
You only need a decent soundcard in your desktop and free software such as REW, Rightmark, Holm or ARTA.

Agreed. Sometimes it is possible to make more accurate measurements using this method than one obtains with expensive special purpose audio test equipment.

I exclusively used specialized test equipment from 1962 to the late 1990s. I popularized the the use of first high end computer audio interfaces and later on as their performance improved, on-board interfaces starting in the late 1990s.
post #35 of 48
Let's just say that I don't know of very many 2-channel integrated amplifiers that are capable of driving a wide range of good speakers well for much under $1000.

For under $1500, some of the better integrated amplifiers that I would be comfortable recommending to a friend are the Creek Evolution 2, Arcam A19, and Musical Fidelity M3i.

The key spec that really tells you how well they can drive a speaker is the output impedance of the amplifier. That is what I look at first.

Amplifiers with an output impedance of less than 0.5 ohms can generally drive almost any speaker with minimal distortion.

With most speakers, 60 watts per channel at 4 ohms or more is usually enough IF the output impedance of the amplifier is low enough.

With very low-sensitivity speakers, less then 86 db/watt, of course, higher power may be needed.

The output impedance of the amplifier tells me a LOT more about how the amplifier will drive a speaker than a power rating determined by driving an 8 ohm resistor.

IMO a power rating determined with an 8 ohm resistor load is almost worthless as an indicator of amplifier performance capabilities (how good it will sound).

Quote:
Originally Posted by Nethawk View Post


What is your recommendation as to a starting price point for a better-designed amplifier?

Edited by commsysman - 7/5/13 at 1:13pm
post #36 of 48
Quote:
Originally Posted by commsysman View Post

The key spec that really tells you how well they can drive a speaker is the output impedance of the amplifier. That is what I look at first.

Amplifiers with an output impedance of less than 0.5 ohms can generally drive almost any speaker with minimal distortion.

With most speakers, 60 watts per channel at 4 ohms or more is usually enough IF the output impedance of the amplifier is low enough.

With very low-sensitivity speakers, less then 86 db/watt, of course, higher power may be needed.

The output impedance of the amplifier tells me a LOT more about how the amplifier will drive a speaker than a power rating determined by driving an 8 ohm resistor.
Surely you're not serious?

Every manufacturer measures Zout at the output terminals, so if an amp has a Zout of 0.5R, then it's DF at 4R is 8. Almost every SS amp for 30 years has bettered that by a factor of 10, most by 100.

You have beclowned yourself again.
post #37 of 48
Quote:
Originally Posted by bo130 View Post

So, Commysman, if "virtually anyone" (trained or untrained listeners) can hear the difference, why haven't they been able to? Should be pretty obvious to prove in any kind of a test, right - if it's as obvious as you claim it is?

(hears crickets chirping...)
post #38 of 48
Quote:
Originally Posted by bo130 View Post

(hears crickets chirping...)
It's not the first time: http://www.avsforum.com/t/1455620/nad-c-356-vs-outlaw-rr2150-vs-marantz-pm8004#post_22910248 and won't be the last.
post #39 of 48
There are two things that one can rely on in your posts; as this example clearly demonstrates-

1- They will contain nothing constructive or relevant on the subject at hand.

2- They always contain gratuitous insults and cheap shots.

This demonstrates to all who have the misfortune to read them a LOT about your lack of maturity and character, and NOTHING about anyone else.

It's very sad and pathetic when a person is so insecure that they have a need to trash other people in this manner.



Quote:
Originally Posted by beaveav View Post

Now that's exactly what I was hoping for. Your combination of arrogant, condescending tone, along with your poor understanding of what you blather about, is precisely what makes your posts so comical. Stephen Colbert would be proud. biggrin.gif

Edited by commsysman - 7/6/13 at 10:10am
post #40 of 48
Quote:
Originally Posted by commsysman View Post

There are two things that one can rely on in your posts; as this example clearly demonstrates-

1- They will contain nothing constructive or relevant on the subject at hand.

2- They always contain gratuitous insults and cheap shots.

This says a LOT about your lack of maturity and character, and NOTHING about anyone else.

It's very sad and pathetic when a person is so insecure that they have a need to trash other people
That's funny because that is how I feel about a lot of your posts.
post #41 of 48
I challenge you to quote where I have directed insults at ANY individual. You are mistaken.

I leave that to others.


Quote:
Originally Posted by 67jason View Post

That's funny because that is how I feel about a lot of your posts.
post #42 of 48
Quote:
Originally Posted by commsysman View Post

I challenge you to quote where I have directed insults at ANY individual. You are mistaken.

I leave that to others.


Quote:
Originally Posted by 67jason View Post

That's funny because that is how I feel about a lot of your posts.
You have hashed people in the way you have commented on the use of certain gear. Sorry if you haven't been able to recogonize your own shortcomings.
post #43 of 48
You are equating the fact that I criticized some EQUIPMENT with the kind of vicious direct PERSONAL insults that I was referring to?

That's a ridiculous comparison.

Quote:
Originally Posted by 67jason View Post

You have hashed people in the way you have commented on the use of certain gear. Sorry if you haven't been able to recogonize your own shortcomings.
post #44 of 48
Quote:
Originally Posted by bo130 View Post

So, Commysman, if "virtually anyone" (trained or untrained listeners) can hear the difference, why haven't they been able to? Should be pretty obvious to prove in any kind of a test, right - if it's as obvious as you claim it is?

(hears more crickets chirping, because Commysman can't back up his statement with these questions)
post #45 of 48
Quote:
Originally Posted by commsysman View Post

There are two things that one can rely on in your posts; as this example clearly demonstrates-

1- They will contain nothing constructive or relevant on the subject at hand.

2- They always contain gratuitous insults and cheap shots.

This demonstrates to all who have the misfortune to read them a LOT about your lack of maturity and character, and NOTHING about anyone else.

It's very sad and pathetic when a person is so insecure that they have a need to trash other people in this manner.
You mean post like this?:
Quote:
Originally Posted by commsysman View Post

These bozos repeatedly make comments to the effect that the amplifier is a very minor factor in the overall sound quality of the audio system. That is precisely opposite to what my ears have told me over the years, and totally destroys their credibility in my mind.


I tell anyone who will listen that they had better get a pretty good amplifier in their system FIRST, or they will have no frigging way to tell how good a CD player or turntable they are auditioning or otherwise listening to. I have heard hundreds of systems over the years and this fact remains a constant, in my experience. Not only that, but without a decent amplifier it can be problematical to evaluate speaker differences, since interaction between cheaper less stable amplifiers and the speakers can confuse the listener about the actual performance capability of the speaker.


To provide low distortion playing MUSIC (no meaningless sinewave test tone frequency response or distortion graphs give you the slightest clue of actual music performance...) an amplifier has to have a stable high-current power supply, precision high-quality capacitors, and a very low output impedance. None of these things come cheap. There are very few halfway decent amplifiers available for less than $1000...but there ARE a few ( the NAD C355BEE is one of the best...).


And of course, there are HUGE differences in the sound of CD players. There has been steady progress in increasing the accuracy and resolution of the DACs used, and the better chips cost enough that you just can't put them in a $300 player and make a profit; it ain't gonna happen. Some of these morons even use DVD players as their main source for playing audio discs, and the circuitry of these things is mainly composed of video chips and the audio circuits are a cheap afterthought. What a joke! The only DVD player I have ever heard that is even half-way decent-sounding for CDs is from OPPO.


The stuff some of these guys spout repeatedly is so ridiculous to anyone who has long experience in audio that it really gets tedious to listen to.
post #46 of 48
Quote:
Originally Posted by commsysman View Post

You are equating the fact that I criticized some EQUIPMENT with the kind of vicious direct PERSONAL insults that I was referring to?

That's a ridiculous comparison.

Quote:
Originally Posted by 67jason View Post

You have hashed people in the way you have commented on the use of certain gear. Sorry if you haven't been able to recogonize your own shortcomings.
see post #45 for an example.
post #47 of 48
Quote:
This demonstrates to all who have the misfortune to read them a LOT about your lack of maturity and character, and NOTHING about anyone else.

It's very sad and pathetic when a person is so insecure that they have a need to trash other people in this manner.



Quote:
Originally Posted by beaveav View Post

Now that's exactly what I was hoping for. Your combination of arrogant, condescending tone, along with your poor understanding of what you blather about, is precisely what makes your posts so comical. Stephen Colbert would be proud. biggrin.gif


The latter is an analysis of the content and tone of most of your posts, and therefore appropriate criticism.. Maybe you should more closely observe what and how you write your comments.
You get only whipped if you do not behave,.
post #48 of 48
Quote:
Originally Posted by commsysman View Post

Let's just say that I don't know of very many 2-channel integrated amplifiers that are capable of driving a wide range of good speakers well for much under $1000.

For under $1500, some of the better integrated amplifiers that I would be comfortable recommending to a friend are the Creek Evolution 2, Arcam A19, and Musical Fidelity M3i.

The key spec that really tells you how well they can drive a speaker is the output impedance of the amplifier. That is what I look at first.

Amplifiers with an output impedance of less than 0.5 ohms can generally drive almost any speaker with minimal distortion.

With most speakers, 60 watts per channel at 4 ohms or more is usually enough IF the output impedance of the amplifier is low enough.

With very low-sensitivity speakers, less then 86 db/watt, of course, higher power may be needed.

The output impedance of the amplifier tells me a LOT more about how the amplifier will drive a speaker than a power rating determined by driving an 8 ohm resistor.

Interesting claim - that integrated amps with source impedances of less than 0.5 ohm are rare.

Let's give it a sniff test:









These are from Stereophile - the first 4 lab (random selection - not cherry picked) tests of SS integrated amps in their archives.

They are frequency response curves into 8,4, and 2 ohm loads, which can be used to discern amplifier source impedance.

We see that none of the amplifiers have significantly greater then 0.25 dB frequency response variation, which is typical of good modern SS amplifiers of any price.. They all show greater loss with lower load impedance (expected). 0.25 dB loss is about the same as 2.5% loss. We'd like to see response into a high impedance load (say 10,000 ohms) to calculate source impedance, but 8 ohms is so much higher than 2 ohms that we can estimate source impedance by saying that 8 ohms approximates a high impedance load. The source impedance of these (and any other good SS amp of any price including those in modern AVRs) is less than 1/40 (2.5%) of 2 ohms or 0.05 ohms.

The claim that integrated amps with source impedances of less than 0.5 ohm are rare is not supported by readily available evidence

Unless we say something crazy like "All good modern SS amplifiers sound the same", amplifier source is not a reliable indicator of amplifier sound quality. ;-)

***Yeah, amps 3 and 4 are a little weak but still beat the 0.5 ohm spec by a factor of 5), but I thought I'd keep you on your toes! ;-)***
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