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ODS123

Advice for Beginners - consider this test from an audio club

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Doesn't matter how it's implemented, it's still only 2 samples being compared.  It's not about how it makes you feel or whether it engages you (so much); how does one sound compared to the other, and which one is X?

 

If your audio memory can't last more than a moment you've got no business taking the test or you'll merely skew the results, "fraughting" the test with problems.

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2 minutes ago, robert_kc said:

The rules for the "Richard Clark $10,000 Amplifier Challenge" also state:  "Compensation will also be made for input and output loading that affects frequency response."  What does this mean?    

 

Not sure, look up Richard Clark and ask him?

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1 minute ago, Don Richard said:

 

Not sure, look up Richard Clark and ask him?

 

If you're not sure about the meaning of this:

  • The rules for the "Richard Clark $10,000 Amplifier Challenge" also state:  "Compensation will also be made for input and output loading that affects frequency response."

Then, why did you say this:

 

1 hour ago, Don Richard said:

 

That's not what was said. He said to do this if one DUT has EQ that cannot be bypassed:

 

 

 

 

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1 hour ago, Don Richard said:

 

So you don't know the basics of ABX/DBT yet you argue about it? ROFLMAO

 

Here's the opening statement from wikipedia re ABX:

  • An ABX test is a method of comparing two choices of sensory stimuli to identify detectable differences between them. A subject is presented with two known samples (sample A, the first reference, and sample B, the second reference) followed by one unknown sample X that is randomly selected from either A or B. 

My earlier questions stand:

 

On 1/8/2019 at 8:38 AM, robert_kc said:

Have the questions I posed in an earlier post about ABX tests for audio been answered?

  • Can most people listen to 2 different music samples (A & B ) that have subtle sound differences, and then listen to Sample X, and reliably identify whether A or B is the same as X?  What percentage of the general population can remember 3 audio samples that have subtle differences?  What percentage of trained listeners?   What are the limits of human memory of sound?  If someone can’t identify X as A or B, does that mean that A & B are the same, or does this show that people can’t remember 3 sound samples with subtle differences, and the ABX test is therefore limited in its usefulness for audio?  (It seems to me this may be different from a scenario where the differences between A & B are significant, e.g., A is a duck quacking and B is a dog barking.)  Is an ABX audio test effectively a shell game – i.e., it confuses people?
     
  • What is the explanation for the phenomenon that many people who participate in formal tests (e.g., ABX, DBT) often cannot reliably identify subtle differences in sound quality (e.g., between different amps, or different bit rates for recordings), whereas many life-long hobbyists report that they can readily hear differences via their casual listening observations?  Are the hobbyists “audiophools”?   Or does this point to a problem with the test methodology? 

I don’t know the answers to these questions, but clearly there is a disconnect between some ABX audio test results and the experience of many life-long hobbyists.

 

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If Clark is talking about input impedance vs frequency and output impedance vs frequency, these are factors that can certainly affect the sound quality of amplifiers and affect frequency response. These things are not EQ or Audyssey, however.

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14 minutes ago, Don Richard said:

 

That could be, but the computer could also be set up to switch amplifiers, speakers, wires, or whatever.

 

I believe these testing devices are custom made, often in-house by companies that use them, and not generally for sale. 

Agreed. A computer could be made to switch just about anything. And agreed if a company went through all the trouble to make it  they would probably keep in house. As the guys that tried to make a go of it at the ABX corp back in the day found out--there just ain't no money in it.

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4 minutes ago, robert_kc said:

 

Here's the opening statement from wikipedia re ABX:

  • An ABX test is a method of comparing two choices of sensory stimuli to identify detectable differences between them. A subject is presented with two known samples (sample A, the first reference, and sample B, the second reference) followed by one unknown sample X that is randomly selected from either A or B. 

My earlier question stands:

 

 

 

If you keep reading that Wiki article it explains and answers most of your questions.

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7 minutes ago, Don Richard said:

If Clark is talking about input impedance vs frequency and output impedance vs frequency, these are factors that can certainly affect the sound quality of amplifiers and affect frequency response. These things are not EQ or Audyssey, however.

 

Are you saying that one factor that can cause two modern amps to sound different is "input impedance vs frequency and output impedance vs frequency".  (I'm not a technical expert, so additional information would be helpful.)

 

If so, does the "Richard Clark  $10,000  Amplifier Challenge" attempt to mask these inherent differences in 2 amps by inserting an equalizer into the audio chain of one amp?

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36 minutes ago, robert_kc said:

Are you saying that one factor that can cause two modern amps to sound different is "input impedance vs frequency and output impedance vs frequency".  (I'm not a technical expert, so additional information would be helpful.)

 

If so, does the "Richard Clark  $10,000  Amplifier Challenge" attempt to mask these inherent differences in 2 amps by inserting an equalizer into the audio chain of one amp?

 

Simple explanation:

 

If the input impedance of an amplifier is too low relative to the output impedance of the source device, frequency response will be affected, usually resulting in less bass.

 

If the output impedance of the amplifier is too high the output voltage will track the impedance of the loudspeaker, which varies with frequency. Such an amplifier that will show a flat frequency response with a resistive load (resistance doesn't vary with frequency) and a variable frequency response when connected to a loudspeaker.

 

I have never heard of this $10K amplifier challenge before this thread, and my reading of his rules is if one of the two amplifiers has an EQ circuit in it that cannot be bypassed, then the other amplifier has an EQ curve identical to the first amplifier inserted into it's signal chain. The first amplifier could instead have an EQ inserted to "unEQ" it's non-bypassable EQ if desired.

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My view is that a lot of these differences are subtle and refined, like the way you can appreciate wine or certain performers, and that’s what you pay for.  Blind wine tastings produce similar results, I’ve heard.  And when talking about the sound of music, it’s elusive.  It’s being able to hear the difference between Brendel’s Schubert vs Kempf’s, for example.  In addition, there is the quality build, people here on this forum have their Klipsch speakers for decades and they still sound great, same is true for audio equipment.  But at the same time it is true that you can enjoy a piece of music you hear in your car radio just as much.  And as long as you stay within your budget.

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1 hour ago, Don Richard said:

 

Simple explanation:

 

If the input impedance of an amplifier is too low relative to the output impedance of the source device, frequency response will be affected, usually resulting in less bass.

 

If the output impedance of the amplifier is too high the output voltage will track the impedance of the loudspeaker, which varies with frequency. Such an amplifier that will show a flat frequency response with a resistive load (resistance doesn't vary with frequency) and a variable frequency response when connected to a loudspeaker.

 

I have never heard of this $10K amplifier challenge before this thread, and my reading of his rules is if one of the two amplifiers has an EQ circuit in it that cannot be bypassed, then the other amplifier has an EQ curve identical to the first amplifier inserted into it's signal chain. The first amplifier could instead have an EQ inserted to "unEQ" it's non-bypassable EQ if desired.

 

Thanks for the explanation.

 

I have no insight into the "Richard Clark  $10,000  Amplifier Challenge"  other than what ODS123 provided:

 

On 1/8/2019 at 3:42 AM, ODS123 said:

It seems Diz, Dean and Dave are hellbent on getting this thread shut down.  I seem to have a struck a nerve with you three.

 

Guys, I'll reply to your posts so long as their pertinent.  It's not a problem if they're snide, snarky or even nasty, so long as their relevent.

 

Tiz..  From Richard Clark's website.  There's a great deal of Q&A from RC to critics such as yourself.  I suggest you go to the website and read for yourself before further hectoring me on this point.

 

Amplifier Comparison Test Conditions

1. Amplifier gain controls - of both channels - are matched to within +- .05 dB.

2. Speaker wires on both amps are properly wired with respect to polarity. (+ and -)

3. That neither amp has signal phase inversion. If so correction will be made in #2 above.

4. That neither amp is loaded beyond its rated impedance.

5. That all amplifiers with signal processors have those features turned off. This includes bass boost circuits, filters, etc. If frequency tailoring circuits cannot be completely bypassed an equalizer will be inserted in the signal path of one of the amps (only one and the listener can decide which) to compensate for the difference. Compensation will also be made for input and output loading that affects frequency response. Since we are only listening for differences in the sonic signature of circuit topology, the addition of an EQ in only one amps signal path should make the test even easier.

6. That neither amp exhibits excessive noise (including RFI).

7. That each amp can be properly driven by the test setup. Not normally a problem but it is theoretically a problem.

8. That the L and R channels are not reversed in one amp.

9. That neither amp has excessive physical noise or other indicators that can be observed by the listener.

10. That neither amp has DC OFFSET that causes audible pops when its output is switched.

11. That the channel separation of all amps in the test is at least 30 dB from 20Hz to 20kHz.

 

 

Do we interpret the highlighted text above to mean that there were two different conditions that might have caused Clark to insert an equalizer into the audio chain of one amp, in an attempt to make the amps sound similar?

  1. If frequency tailoring circuits cannot be completely bypassed, OR 
  2. If the amp's "input and output loading" affects frequency response.

On one hand, this seems to me to be pointless speculation.   OTOH, ODS123 cited the "Richard Clark $10,000 Amplifier Challenge" as strong evidence that all modern "linear" amps sound the same.   I'm wondering if this assertion needs to be clarified to say something like "all modern amps that are linear for resistive loads, and are linear when connected to a wide range of loudspeakers"?  If so, what's the difference between this statement and "In the real world, all modern amps don't sound the same?"


 

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To all of you who select your gear based on ABX/DBT testing: Good luck. Have fun. Enjoy the system you assemble based on ABX/DBT.

 

Personally, I will continue to use the Observational method that I have used with great success for 47 years because I know it works for me.

 

The best thing I can do for a newbie is to teach them how to trust their own ears while observing subtle differences in the sound of audio gear. ;)

 

Just my opinion. :)

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2 hours ago, Don Richard said:

 

No, he doesn't understand at all. ABX/DBT does not compare 3 samples at once. The subject listens to one sound sample, a switch is made, and the question is asked, "Is there a difference or not." Testing is repeated several times with neither the tester or subject knowing whether A, B. or X (no change) has been selected. The test equipment records the results. 

 

 

I thought I made that clear in an earlier post. I sat in on the very first public demo of the AB/X box at an Audio Engineering Society meeting over 40 years ago. It ONLY identifies, statistically, detectable DIFFERENCES between 2 similar things. Nothing more.

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Everything presented here is just OPINIONS, including mine. However some of us have had real world experience in these areas, along with an electronics and Audio construction background, not opinions "plucked from air" based on something read "somewhere" on the web. Just sayin'

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18 minutes ago, ClaudeJ1 said:

Everything presented here is just OPINIONS, including mine.

Get with the program.  All opinions are equally valid, however ridiculous./s

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This thread is great & all....  since we're into hijacking....will the plan take off from the conveyor belt??

 

 

 

 

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Like I've said before merits pro or con of ABX testing, I just liked the fact that with the old ABX corp equipment the change between A and B was noiseless and almost instantaneous. So which one do you like better A? or B? Not after f'ing around changing cables/components but right now.  A? or push a button B? Release the button A? or push the button B? Relying on MY long term auditory memory is useless when it comes to subtle differences. And the older I get I think the more useless it is.

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11 minutes ago, Coytee said:

This thread is great & all....  since we're into hijacking....will the plan take off from the conveyor belt??

 

 

 

 

A plan will not, however, a certified  airworthy airplane, with tires properly inflated, will takeoff easily as its means of thrust is independent of the conveyor belt and exceeds the coefficient of friction of the free-spining wheels upon the conveyer belt surface.

 

This assumes the air density is such that the subject airplane is capable of flight in the same location as the conveyer belt.

 

Interesting you bring up flight as there is a direct LINEAR relationship between the amount of lift any given airfoil creates and the surface area of the wing.

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7 minutes ago, dwilawyer said:

A plan will not, however, a certified  airworthy airplane, with tires properly inflated, will takeoff easily as its means of thrust is independent of the conveyor belt and exceeds the coefficient of friction of the free-spining wheels upon the conveyer belt surface.

 

This assumes the air density is such that the subject airplane is capable of flight in the same location as the conveyer belt.

 

Interesting you bring up flight as there is a direct LINEAR relationship between the amount of lift any given airfoil creates and the surface area of the wing.

I haven't seen the length of the conveyor belt in question.
 

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