Tube amps?

[mtrycrafts]

I don't care to speculate on the typos or lies(which ever they may be).

Zumbo, here are some basic physical rules....

I(current in amperes)*V(voltage)=P(power, in watts).

A standard home line is 120V*15 amps = 1800 watts. The heaviest capacity 120V line allowable by elecrical code is 120V*20 amps = 2400 watts.

Each amplifier class has a typical efficiency approximation. A percent of the total power that it can turn into output power. Here is a breakdown:

Switching Amplifiers:85%-95%
Class AB: 50%
Class A: 25%

To get the rated 2 x 800 watts @ 8 ohms of the Ashly MFA-800 claims, if it was class A output stages, it would have to consume 6400 watts. Not possible from a 120VAC line. But that is only the beginning of the consideration. A Class A amplifier also produces far more heat than any other class, and it(unlike other classes which only disapate in proportion to the power being actually output from the amplifer) disappates the full wasted percent of energy 100% of the time. So that means you have a 4800 watt space heater in case of the MFA-800. The heatsink/cooling solution would not even fit in the case size of the MFA-800, and the power supply alone would be as big as the entire case. In fact, in AB operation, it could not produce 800 x 2 from a 120VAC house line. It must be a switching amplifier to reach even this spec with continous power output.

-Chris

EDIT: Corrected number of channels of MFA-800.

Those transformers are not that big either, compared to some toroidal ones in home audio gear. And, without knowing the caps, who knows.

Yes, I would tend to agree that a class A amp to put out such power would need huge heat sinks to begin with. I didn't see much of a heat sink.

 

[mtrycrafts]

Look through for what purpose?

-Chris

The amp has 3 DC voltage, load dependent, levels on the rail, switched by ultra fast MOSFETs. Shipping weight 61 and 68 lbs for the two models.
The 6000 will use 10A on the line when outputting 800watts per channel into 4 ohms. Interesting trick. 1200 watts input, 1600 watts output.

 

[woodyf]

I will email Ashly and try to get a straight answer.

I emailed Ashly and got a prompt answer, now their is no doubt.

Subject: Re: are the FET-2000 and FTX-2001 Class A or Class AB Type:


Class A front end with a Class B output.

It does provide a bit of extra home heating when run
with a low impedance, however the sonic properties
in my opinion make it well worth it.
For pro sound on the road I prefer lighter weight more efficient class D
with a Switching power supply to cut down on labor and trucking.
For a fixed installation, You can't beat the sound of the
Mos Fet. At Idle a properly Biased Mos Fet amp should pull about 275mA.
When running with a dynamic signal @4ohms with a kick drum bumping full output
you're probably going to average ~4-6A. I have successfully Run 2 FET 2000Ms on one 20 amp
line all night at 8 ohms bridged with a compressed signal driving my JBL SRX high packs.


Best Regards,
Mike Bow

 

[WmAx]

I emailed Ashly and got a prompt answer, now their is no doubt.

Class B output? That's rare. Most amplifers are class AB(operate as class A at low signal levels, and switch to class B operation at moderate to large signal levels).

-Chris

 

[mtrycrafts]

I figured that was a stupid question. But, while I had you, I figured I would ask. Thanks for all your help.

Never a stupid question, just the ones not asked How else will anyone learn if they don't ask questions??? I always have to ask questions to be sure and to clarify things.

 

[kgturner]

butler amps

to answer the original question before the poster went off on a tangent about pro amps - from what i recall, the butler amps are a hybrid design using tubes as the input stage and transistors in the output stage. so it is not a true tube amplifier in the sense that there are no tubes in the output stage. as far as what sounds better, that's up to you to decide. i replaced my aragon palladium ii monoblocks with cary audio slm-200 monoblocks. the aragon's sounded better in some respects and the cary's sounds better in some respects. your best bet is to listen to some tube amps in your system and decide for yourself if you like how they sound compared to your solid state amplifier. good luck.

kevin t

 

[highfihoney]

to answer the original question before the poster went off on a tangent about pro amps - from what i recall, the butler amps are a hybrid design using tubes as the input stage and transistors in the output stage. so it is not a true tube amplifier in the sense that there are no tubes in the output stage. as far as what sounds better, that's up to you to decide. i replaced my aragon palladium ii monoblocks with cary audio slm-200 monoblocks. the aragon's sounded better in some respects and the cary's sounds better in some respects. your best bet is to listen to some tube amps in your system and decide for yourself if you like how they sound compared to your solid state amplifier. good luck.

kevin t

great response & i couldnt agree more,while all amp's weather they be a pro amp or a hifi amp(tube or solid state) are pretty much the same device made to do the same job all these different type's of amplifier's will not sound the same,ive owned tube gear,solid state & pro gear,class a ,class ab ect & spec's are not the total solution to putting together a great sounding rig.

i see lot's of responses fixating on dollar to watt's ratio's & that's not the total sum of our hobby,when you start to get away from reciever's & av center's & get into well designed seperate's you can see how different gear has entirely different sonic signature's & that each different type of component will respond quite differently to different type's of amplification.

to fully understand all the different type's of amp's tube or solid state you would need to set up a rig based on what each different amp is good at & spec's are only a part of the picture not the whole shebang.

 

[WmAx]

i see lot's of responses fixating on dollar to watt's ratio's & that's not the total sum of our hobby,when you start to get away from reciever's & av center's & get into well designed seperate's you can see how different gear has entirely different sonic signature's & that each different type of component will respond quite differently to different type's of amplification.

Different sonic signatures? If so, these will be easily measurable/predictable, and they will be correlatable with existing perceptual research that shows the measured difference is within an audible threshold.

-Chris

 

[highfihoney]

Different sonic signatures? If so, these will be easily measurable/predictable, and they will be correlatable with existing perceptual research that shows the measured difference is within an audible threshold.

-Chris

hi cris,i can see your sceptical so i'll give it a shot explaining what i have found out to be true but im not an expert so bear with me as i may screw up some spelling's & such.

measurable yes predictable no

if you "really" want to measure these difference's you will need alot more than a radio shack spl meter,these differences can in fact be seen using an accoustic analizer or even a quality pro equlizer with a built in analizer function with the ability to save setting's & a mic,also in order to see these difference's you cant use a reciever,pre/pro or any other device that add's anything to the signal or processes the signal in any way,either amp's with their own gain control's need to be used or a passive preamp,either of the 2 will work fine but the signal from the cd player to the amp must remain unaltered with controled & measured wattage's.

several model's are there for the asking,dbx 20/20,mcintosh aa2 ,just to name a few,the dbx is a pro eq with a built in analizer function & the mcintosh is strictly an accoustic analizer but both are used for room & system analasis,i think rive's audio & also accuphase both make variation's of theese too but im not positive.

btw,i own the dbx 20/20 & it's analizer function is so sensitive that i can see on the display when my dog walk's thru the room while the music is playing at level's over 110db.

also for arguement's sake let's use two different mcintosh amp's,one 100 watt solid state & one 100 watt tube amp,the reason i chose mcintosh for both amp's is they both have power level meters that are calibrated the same way or if that seem's strange substitute any other amp & use a seperate watt meter in it's place.

start with the solid state amp,combine it with a cd player,pick a spot in or near your listening posistion & place the dbx 20/20's mic where it's pointing tword's the center of the speaker's,now remember that both amp's have gain control's to be used as volume control.

the analizer isnt affecting the sound in any way as it is not hooked up between the amp & cd player its only getting it's information thru the business end of the microphone & showing the result's on the display,also the dbx will show what is in the "audible threshold"

start the cd playing then after the music is going hit the analize function on the dbx,turn the gain control on the amp up to a desired wattage,let's just say 20 watt's,commit these setting's to memory in the dbx.

now to test the tube amp repeat these step's using 20 watt's again from the tube amp & saving these analized setting's to memory on the dbx,now compare the two different setting's that were commited to memory & you will see in person that each amp has it's own sonic signature,not nessacarly better only different.

the same type test's can & will show visable difference's in two dirrerent amplifier's with spec's that are very close together with both amp's being solid state,take a pair of mcintosh mc1000 watt solid state monoblock's & compare them with a pair of musicial fidelity 1kw 1000 watt monoblock's & you will also see difference's in performance level's.

one amp might present a stronger bass while the other amp might produce stronger mid's or high's while both amp's were running the same amount of power but no matter what visable difference's will be there & you will be able to see them plain as day & the result's will show that the difference's are infact within the audible range.

i dont preach this to be the bible of hifi but it's an easily checked fact if anybody really care's enough to line up all the gear & spend an hour or two comparing .

part of what i was talking about in my response above was also finding out what gear work's best with other gear,some gear sound's like hell when teamed up with certian gear & other gear that sounded great on one rig might not sound as good on another & rated spec's are only a part of putting together a great sounding rig,keep in mind that oponion's about what sound's great differ widely but none the less difference's can be measured & seen if you care to take the time.

have a nice weekend.

 

[zumbo]

Now, that was the answer I have been looking for.

Thank you highfihoney.

I am one who believes I can hear a difference in different amps.

 

[WmAx]

if you "really" want to measure these difference's you will need alot more than a radio shack spl meter,these differences can in fact be seen using an accoustic analizer or even a quality pro equlizer with a built in analizer function with the ability to save setting's & a mic,also in order to see these difference's you cant use a reciever,pre/pro or any other device that add's anything to the signal or processes the signal in any way,

1. It is highly questionable to test amplifier or any other electrical device's performance with acoustic measurements. This testing is sensitive to environmental noises and your specific position during the test. Such testing is very difficult to replicate at a later time, as well, due to the complications of setting up the microphone in the exact same place the 2nd time, and depends on the environmental conditions remaining exactly the same at a different time.

2. Far higher accuracy(and the only accepted standard) of measurement is obtained by directly measuring the electrical signal output from the amplifier. This can be accomplished at home by using a voltage divider feeding off the speaker terminals to an ADC input to a computer soundcard. You can input test signals to the amplifier and then sample with the computer ADC, the resulting signal modification for accurate comparison using the appropriate software. The relevant parameters: THD, IMD, frequency response and SNR are accurately measurable using this method. Note: using the loudspekaer as the load means these test results are only valid for the particulare loudspeaker under test. Ideally, a combination of resistive load ranges, followed by reactive load analysis in a controlled manner is warranted in order to be able to predict the behaviour of the amplifier with different loudspeaker loads.

Anyways, I'm not going to comment on the rest of your post since it is an expansion of an odd(and inaccurate) test method. I will be more than happy to explain specific details of how to measure relevant parameters accurately, if you like. Your amplifier may very well be different, but it is easily measurable, and th effects easily predictable, as I specified earler.

-Chris

 

[mtrycrafts]

hi cris,i can see your sceptical

Me too.


so i'll give it a shot explaining what i have found out to be true but im not an expert so bear with me as i may screw up some spelling's & such.

I think, you found out something. Whether it is true or not has yet to be determined as it cannot be from the info you are giving.
And, yes, we can test what you hear, or hear component differences, but, as you may know, you can only use your ears, not your eyes or others help That would be a DBT comparison of amps, other components, level matched, of course, to .1dB spl

predictable no

Oh, but you have not spoken with the experts in the field







the same type test's can & will show visable difference's in two dirrerent amplifier's

Visible??? I thought you will be listening to the amps, not look at the visible traces on a scope.

Besides, I bet you will see a visible differences between cables measurements too, even if the cables are the same and one happens to be a foot shorter. What do you think?


i dont preach this to be the bible of hifi but it's an easily checked fact if anybody really care's enough to line up all the gear & spend an hour or two comparing .

Well, hardly a fact. 20+ years of DBT has shown otherwise.

 

[mtrycrafts]

Now, that was the answer I have been looking for.

Thank you highfihoney.

I am one who believes I can hear a difference in different amps.

If you are a believer, then it is easy to accept his post You saw the thread on ID, right

 

[highfihoney]

hi cris,i can see your sceptical

Me too.


so i'll give it a shot explaining what i have found out to be true but im not an expert so bear with me as i may screw up some spelling's & such.

I think, you found out something. Whether it is true or not has yet to be determined as it cannot be from the info you are giving.
And, yes, we can test what you hear, or hear component differences, but, as you may know, you can only use your ears, not your eyes or others help That would be a DBT comparison of amps, other components, level matched, of course, to .1dB spl

predictable no

Oh, but you have not spoken with the experts in the field







the same type test's can & will show visable difference's in two dirrerent amplifier's

Visible??? I thought you will be listening to the amps, not look at the visible traces on a scope.

Besides, I bet you will see a visible differences between cables measurements too, even if the cables are the same and one happens to be a foot shorter. What do you think?


i dont preach this to be the bible of hifi but it's an easily checked fact if anybody really care's enough to line up all the gear & spend an hour or two comparing .

Well, hardly a fact. 20+ years of DBT has shown otherwise.

ok there's a difference between sceptical about thing's & bieng blinded by sceptisism,how can you infer that beacuse i can see & hear difference's in amplifier's that i believe in cable voodo,your post is more of a rant than an informational discussion & is based on your personal belief's instead of information.

for what's it's worth i dont believe anything in audio that i cant prove by seeing it with my own eye's,yes seeing,you cant see difference's in cable's on any form of testing equipment that i know of unless your running wire's not capable of handeling the load,the human ear is subject to way too many factor's to be the most accurate form of measurement & is affected by thing's like the placebo affect & memory.

the original question posed to me was to show how amplifier's have different sonic signaturer's to where they can be seen & measured,not heard but seen,i have done that & shared the info with everybody so they can also perform these test's,i have also listed the gear needed to do a measured & controled test to where all factor's are a constant.

what is your point & where are you going with all of this? im not talking about dbt test's & you know that,would your reply had been any different had i said i could only hear difference's & not see them,i think the wording would have been different but the end result would have been the same.

i never claim to be an expert on anything other than setting up a rig that sound's good to me & try to do so as sensibly & as affectively as possible by investigating everything i can myself & i never rely on myth's.

i still dont see the point of your post & im far from confused.

 

[highfihoney]

1. It is highly questionable to test amplifier or any other electrical device's performance with acoustic measurements. This testing is sensitive to environmental noises and your specific position during the test. Such testing is very difficult to replicate at a later time, as well, due to the complications of setting up the microphone in the exact same place the 2nd time, and depends on the environmental conditions remaining exactly the same at a different time.

2. Far higher accuracy(and the only accepted standard) of measurement is obtained by directly measuring the electrical signal output from the amplifier. This can be accomplished at home by using a voltage divider feeding off the speaker terminals to an ADC input to a computer soundcard. You can input test signals to the amplifier and then sample with the computer ADC, the resulting signal modification for accurate comparison using the appropriate software. The relevant parameters: THD, IMD, frequency response and SNR are accurately measurable using this method. Note: using the loudspekaer as the load means these test results are only valid for the particulare loudspeaker under test. Ideally, a combination of resistive load ranges, followed by reactive load analysis in a controlled manner is warranted in order to be able to predict the behaviour of the amplifier with different loudspeaker loads.

Anyways, I'm not going to comment on the rest of your post since it is an expansion of an odd(and inaccurate) test method. I will be more than happy to explain specific details of how to measure relevant parameters accurately, if you like. Your amplifier may very well be different, but it is easily measurable, and th effects easily predictable, as I specified earler.

-Chris

hello cris,i dont like to get into pissing contest's over who's gear is better than the other guy's or who's smarter & i think it's unproductive & lesson's any learning that can be had so i thank you for your sensible & fact based response to my last post on this subject.

how can you say that gear cant be measured using accoustic measurement's isnt that part of the design process right along side resistive load test's & accoustical testing in an anechoic chamber ?

were not talking about measurement's needed for building an amplifier only measurement's accurate enough to show difference's in different amplifier's performance's.

i dont think the form of testing i mentioned is as flawed as you say,were not talking about long delay's between measuring the performance of the 2 seperate amplifier's just a matter of minute's & the mic never move's from it's original position,the enviromental condition's do not change in the room within a 10 minute time frame to the point of totally contaminating any result's & no testing is done at a later time,granted the result's can be affected by many thing's such as my place in the room & anything else that that has been changed but if one realize's that right from the start & tries hard to keep every thing a constant then decent result's can be achieved,not 100% accurate but within a degree of certainty.

i agree that the result's would only be aplied to the exact same loud speaker that was in the test but isnt that the whole point to find the amp that perform's best in your system ?

ok let me ask this,if an anechoic chamber were used for control purposes & all switching of amplifier's was done outside the room & both accoustic responses from each amplifier were measured & recorded wouldnt this be the exact same thing but only with 100% accuracy ?

being that i know zip about computer testing of anything i'll take your word for these thing's as fact & from your description of the other form's of testing it sound's like you know about them so please explain to me how an accousticly measured test is so flawed that any & all result's from such a test (no matter how tight the control measures) are flawed beyond the point of being used.

i really would like to learn why amplifier's should'nt be tested & measured accousticly being that the end result from the amplifier is an accoustic response that we hear.

have a good evening.

 

[mtrycrafts]

,your post is more of a rant than an informational discussion & is based on your personal belief's instead of information.

Actually, it is based on 25+ years of DBT evidence, nothing to do with my beliefs at all.


for what's it's worth i dont believe anything in audio that i cant prove by seeing it with my own eye's,

Be careful, sight perception can be fooled as well. One reason eyewitness testimony is not well regarded in the court of law.



yes seeing,you cant see difference's in cable's on any form of testing equipment that i know of unless your running wire's not capable of handeling the load,

If you measure their characteristics, Inductance, resistance, or plot their response curve it becomes very visible and different. Only thing is, not enough to be audible. Same with amps, but what would 25+ years of testing tell us?


the human ear is subject to way too many factor's to be the most accurate form of measurement

And the eye is not?

& is affected by thing's like the placebo affect & memory.

Yes, it is and eyes are not affected by placebo?

the original question posed to me was to show how amplifier's have different sonic signaturer's to where they can be seen & measured,not heard but seen,

Then that question is irrelevant as it has no meaning to audibility, unless it is also combined with known threshold of detection, or verified by DBT listening.




what is your point & where are you going with all of this? im not talking about dbt test's & you know that,

Visual differences are meaningless to audible differences without other info stated above.

would your reply had been any different had i said i could only hear difference's & not see them,i think the wording would have been different but the end result would have been the same.

The answer would have been the same. Evidence is not supporting your perceptions. I have to accept the body of evidence, not anecdotes.

i can myself & i never rely on myth's.

As it should be. Since you like to set up and test, perhaps DBT should be part of that listening comparisons? After all, that is the gold standard of testing in science.

 

[highfihoney]

,your post is more of a rant than an informational discussion & is based on your personal belief's instead of information.

Actually, it is based on 25+ years of DBT evidence, nothing to do with my beliefs at all.


for what's it's worth i dont believe anything in audio that i cant prove by seeing it with my own eye's,

Be careful, sight perception can be fooled as well. One reason eyewitness testimony is not well regarded in the court of law.



yes seeing,you cant see difference's in cable's on any form of testing equipment that i know of unless your running wire's not capable of handeling the load,

If you measure their characteristics, Inductance, resistance, or plot their response curve it becomes very visible and different. Only thing is, not enough to be audible. Same with amps, but what would 25+ years of testing tell us?


the human ear is subject to way too many factor's to be the most accurate form of measurement

And the eye is not?

& is affected by thing's like the placebo affect & memory.

Yes, it is and eyes are not affected by placebo?

the original question posed to me was to show how amplifier's have different sonic signaturer's to where they can be seen & measured,not heard but seen,

Then that question is irrelevant as it has no meaning to audibility, unless it is also combined with known threshold of detection, or verified by DBT listening.




what is your point & where are you going with all of this? im not talking about dbt test's & you know that,

Visual differences are meaningless to audible differences without other info stated above.

would your reply had been any different had i said i could only hear difference's & not see them,i think the wording would have been different but the end result would have been the same.

The answer would have been the same. Evidence is not supporting your perceptions. I have to accept the body of evidence, not anecdotes.

i can myself & i never rely on myth's.

As it should be. Since you like to set up and test, perhaps DBT should be part of that listening comparisons? After all, that is the gold standard of testing in science.

this is starting to look more like a troll as oposed to a real response or a question but i'll bite.

accoustic analyzer's are used in audio to measure responses & they do just that,i am not a engineer or in the feild but that does not mean im not able to read the manual of such a device & use it properely.

your plugging dbt test's as if they are all there is but would the test subject's used be able to tell the difference in a pair of true full range speaker's against a pair of bose 901 speaker's,most likely not,dbt testing rely's on the subject's memory & weather or not it's the standard it's the most flawed way to test anything.

your cable analogy comparing amp's with cable's wont hold water,were not talking about minute differences that are so low they cant be heard were talking about measureable & recordable responses that can be heard & seen on a device designed to measure & capture accoustic response's.

"visual difference's are meaningless to audible difference's without other info stated above"

that's an untrue statement,when you can take visual image's that are saved within a device & have 2 seperate setting's now you can switch back & forth between the 2 seperate setting's derived directly from both amplifier's & hear the difference's between the seperate setting's on a single amplifier it's hard to deny that there is merit to it.

i have tried this type of testing & seen & heard the result's with my own eye's & ear's,before you condem accoustic testing as unreliable you should see for yourself.

i ask you the same question that i posed above,if this test was performed in an anechoic chamber with all varible's remaining constant how can it be flawed?

 

[WmAx]

how can you say that gear cant be measured using accoustic measurement's isnt that part of the design process right along side resistive load test's & accoustical testing in an anechoic chamber ?

The acoustic aspect end of measuring electronics does only one thing: masks the response and makes interpretation more difficult.

i dont think the form of testing i mentioned is as flawed as you say,were not talking about long delay's between measuring the performance of the 2 seperate amplifier's just a matter of minute's & the mic never move's from it's original position,the enviromental condition's do not change in the room within a 10 minute time frame to the point of totally contaminating any result's & no testing is done at a later time,granted the result's can be affected by many thing's such as my place in the room & anything else that that has been changed but if one realize's that right from the start & tries hard to keep every thing a constant then decent result's can be achieved,not 100% accurate but within a degree of certainty.

The only differences one could possibly show with such measurement are rather large frequency response differences or severe noise differences. You can not begin to measure distortions accurately.

ok let me ask this,if an anechoic chamber were used for control purposes & all switching of amplifier's was done outside the room & both accoustic responses from each amplifier were measured & recorded wouldnt this be the exact same thing but only with 100% accuracy ?

This would increase repeatibility/accuracy, but would be completely inferior to direct electrical signal analysis.

so please explain to me how an accousticly measured test is so flawed that any & all result's from such a test (no matter how tight the control measures) are flawed beyond the point of being used.

In-room acoustic measurements are heavily masked by the room's response. You are unable to analyse the specific harmonic structure for THD analysis, nor can you analyse noise carefully, because of the room's inherant noisefloor. The frequency response in a room is also very rough, compared to the actual electrical signal response from the amplifier. Only large frequency response differences can be detected with acoustic response measurement.

-Chris

 

[zumbo]

I want to thank all of you, and I hope everyone is having fun. This is the kind of discussion I was hoping to get going. Thanks again!

 

[mtrycrafts]

accoustic analyzer's are used in audio to measure responses & they do just that,i am not a engineer or in the feild but that does not mean im not able to read the manual of such a device & use it properely.

Unfortunately there is more to this than just reading such a manual, much more. Chris gave you a sufficient response on the flaws of using these acoustic tests for purposes beyond their capability. No need to repeat them.

your plugging dbt test's as if they are all there is but would the test subject's used be able to tell the difference in a pair of true full range speaker's against a pair of bose 901 speaker's,most likely not,

You should read more than manuals. Research the Canadian Research Council and their 30 years of speaker research under DBT listening protocols. May want to read some of Dr Floyd Toole's AES papers from AES.org. It will cost you but good education has a cost. DBt is a 'gold standard' for a very good reason.

dbt testing rely's on the subject's memory & weather or not it's the standard it's the most flawed way to test anything.

That is your opinion. You are dismissing all of science. You are embarrassing yourself.

your cable analogy comparing amp's with cable's wont hold water,were not talking about minute differences that are so low they cant be heard were talking about measureable & recordable responses


Oh, please. Cable differences are measurable and recordable differences.



"visual difference's are meaningless to audible difference's without other info stated above"

that's an untrue statement,when you can take visual image's that are saved within a device & have 2 seperate setting's now you can switch back & forth between the 2 seperate setting's derived directly from both amplifier's

Visible differences are not an indication of audible differences. Depends on magnitude and accuracy of the measurements. Your protocol is flawed, grossly, as was pointed out, hence meaningless.


hear the difference's between the seperate setting's on a single amplifier it's hard to deny that there is merit to it.

Not at all, your listening protocol is wanting as your measuring protocol, hence your whole experiment is unreliable.

i have tried this type of testing & seen & heard the result's with my own eye's

No doubt you have. But, repeating the same flawed protocol will yield unreliable results time after time.

ear's,before you condem accoustic testing as unreliable you should see for yourself.

Nothing to see. It is flawed.

i ask you the same question that i posed above,if this test was performed in an anechoic chamber with all varible's remaining constant how can it be flawed?


You are still measuring speaker responses, not amp property. You don't measure amp distortion through a speaker with an spl meter not even in an anechoic chamber You will get speaker distortion. SPL meters just cannot measure into low enough regions. Same for frequency response, etc. There is really nothing further to discuss on this.