If you expect people to accept your claims, you need to provide the evidence; what were the specific test conditions, what equipment was used (both test equipment and DUT), what signal levels were used, etc.
Lacking evidence, your just making unsubstantiated claims, nothing more.
Mike
It would be interesting to dig a bit deeper to see where does this non-linearity originate from. Provided that the input sweep signal is near-ideally flat, why not measuring stage by stage and see if it is an intended effect or a design flaw in the power stage, for example. Also, It would be very useful to see potential differences in response in function of power and load impedances.
How to sell amplifiers - cheat the sound ?
Thread starter, please allow some analysis of what you wrote:
How did you arrive at this curve? Is it taken from the output of this reputable amp?
So this curve is only valid with a speaker load? "Some amps" or "common practice in the audio industry" ?
Oh, I see it is "your beloved SS amp", so you even know what we use at home.
And "it is common in CD players, DAC, phono" as well, does this mean the response aberrations even add,
so that we arrive at 24 dB plus in a CD, DAC and amp chain?
This may tell also why the figure is around -90dB full scale although:
We clearly see it is not a scope, but no idea even now.
No, I will not. I accept (others will not) that you don't want to tell the name of this "reputable 70 Watts hifi amplifier"
but the rest is complete BS*, the full word is not allowed here for good reasons.
Some examples would be fine though. No company will feel offended by what you write here.
On the other hand, cheat and trickery are strong accusations.
In my time of 35+ years of professional experience I have never seen any amp, receiver or someting like this with intended non-flat frequency response.
The only exception I recall is a very old Bang&Olufsen receiver with permanent loudness, a useful feature for some equipment.
The testing, as requested, is already done. Especially your proposition "some tone controls are activated only by a speaker load" is near impossible,
because most tone controls are in the preamp chain and just don't know about the existence of a load
(some very rare exceptions have their controls in the power section).
So please which particular speaker did you use?
But later:
Speaker only phenomenon or not? Again, a clear idea of what you measured and want to show us may be useful.
"The sample was at around 10 watts", but later "no, it was made to around 15 watts".
I don't care, but it may be easy to blow your tweeters at a level like this and probably you are deaf after the "test".
After all, do I reply to sort of trolling?
Thread starter, please allow some analysis of what you wrote:
How did you arrive at this curve? Is it taken from the output of this reputable amp?
So this curve is only valid with a speaker load? "Some amps" or "common practice in the audio industry" ?
Oh, I see it is "your beloved SS amp", so you even know what we use at home.
And "it is common in CD players, DAC, phono" as well, does this mean the response aberrations even add,
so that we arrive at 24 dB plus in a CD, DAC and amp chain?
Would you mind to show us what kind of instrument it is?
This may tell also why the figure is around -90dB full scale although:
We clearly see it is not a scope, but no idea even now.
No, I will not. I accept (others will not) that you don't want to tell the name of this "reputable 70 Watts hifi amplifier"
but the rest is complete BS*, the full word is not allowed here for good reasons.
Some examples would be fine though. No company will feel offended by what you write here.
On the other hand, cheat and trickery are strong accusations.
In my time of 35+ years of professional experience I have never seen any amp, receiver or someting like this with intended non-flat frequency response.
The only exception I recall is a very old Bang&Olufsen receiver with permanent loudness, a useful feature for some equipment.
The testing, as requested, is already done. Especially your proposition "some tone controls are activated only by a speaker load" is near impossible,
because most tone controls are in the preamp chain and just don't know about the existence of a load
(some very rare exceptions have their controls in the power section).
So please which particular speaker did you use?
But later:
Speaker only phenomenon or not? Again, a clear idea of what you measured and want to show us may be useful.
"The sample was at around 10 watts", but later "no, it was made to around 15 watts".
I don't care, but it may be easy to blow your tweeters at a level like this and probably you are deaf after the "test".
After all, do I reply to sort of trolling?
That, and details on test setup. How do we exclude incorrect software setting, for example?
At this point I pray for someone to come to my rescue. Didn't want to launch a tsunami.
east electronics
xrk971
as audio: Especially your proposition "some tone controls are activated only by a speaker load" is near impossible (the amplifier brand is from Germany in this case, the other one I had is from England)
It is very easy to have more gain if impedance raise and in between stages at some frequency a little like a needle magnet reacts to capacitance and resistance of the loading.
I am using the QA401 48K/192KSPS 24-BIT USB AUDIO ANALYZER
I use voltage dividers to not overload the inputs
I use also QA101 Mixed Signal Oscilloscope
$409
and Tecktronics digital oscilloscope
I know my stuff and can measure distortion and response between each stage of an amp, simple capacitors, isolators, step down transformers are used both at my work and in building my audio amps.
I have reference amps to always check that the measurements are valid ones.
I'm a bit confused on something here. In post #1 you say
That seems to suggest that you are saying the source components (or amplification needed to get a source component up to line level such as a phono stage) also exhibit this type of response.
Is that what you are really suggesting... or have I interpreted the meaning of that incorrectly ?
That seems to suggest that you are saying the source components (or amplification needed to get a source component up to line level such as a phono stage) also exhibit this type of response.
Is that what you are really suggesting... or have I interpreted the meaning of that incorrectly ?
Well, if there is great bass and lots of detail, and maybe if there is also a decent impression of mid frequency reproduction, then why would anyone want to give that up? Trade an actual positive experience for a flat frequency response graph?
Especially if one is not a well equiped DIYer with gear to measure frequency response, distortion, slew rate, ... , of one picks what "sounds right" as this provides the most happiness.
http://www.stereophile.com/content/thöress-300b-monoblock-power-amplifier-measurements . Now this is an exceedingly high end low power hand made SET with a high output impedance. That's about the worst I have ever seen into a typical speaker load.
My amps a bit diffrent, its A 2 U size with zero volume control in it, just pure amp, and then the pre amp is tubes that comes in a separate case.
Should have zero tone control things going on inside it
Besides that, I have a tube pre amp that my dad designed. Zero tone control going on inside here too
Should have zero tone control things going on inside it
Besides that, I have a tube pre amp that my dad designed. Zero tone control going on inside here too
..
Sorry for interrupting, gentlemen,
may I ask to go to topic again, it is: How to sell amplifiers (cheat the sound)
Thread starter tried to prove his proposition of "common practice in the audio industry" with a suspicious looking curve.
The curve in his post 1 is obviously not made with Corel draw, but shows signs of digital aberration and probably some
misunderstanding of the task at the same time.
This graph is not sufficient to underline the original proposition. In fact all practical evidence shows that the contrary
must be true. Not only from my own experience, described before, bur many others may agree.
So the thread starter is asked again to refine his statement and show what "we" missed in decades.
Quote: "It is very easy to have more gain if impedance raise and in between stages at some frequency a little like a needle magnet reacts to capacitance and resistance of the loading"
It speaks for itself.
Quote: "QA401 48K/192KSPS 24-BIT USB AUDIO ANALYZER
I use voltage dividers to not overload the inputs
I use also QA101 Mixed Signal Oscilloscope
$409
and Tecktronics digital oscilloscope
I know my stuff "
OK I admit to not know these. My stuff is only Teccckkktronixxx etc.
Again, I do not completely understand, are we falling into a troll trap? Did I do tricky even freq. responses all the time without knowing it?
Sorry for interrupting, gentlemen,
may I ask to go to topic again, it is: How to sell amplifiers (cheat the sound)
Thread starter tried to prove his proposition of "common practice in the audio industry" with a suspicious looking curve.
The curve in his post 1 is obviously not made with Corel draw, but shows signs of digital aberration and probably some
misunderstanding of the task at the same time.
This graph is not sufficient to underline the original proposition. In fact all practical evidence shows that the contrary
must be true. Not only from my own experience, described before, bur many others may agree.
So the thread starter is asked again to refine his statement and show what "we" missed in decades.
Quote: "It is very easy to have more gain if impedance raise and in between stages at some frequency a little like a needle magnet reacts to capacitance and resistance of the loading"
It speaks for itself.
Quote: "QA401 48K/192KSPS 24-BIT USB AUDIO ANALYZER
I use voltage dividers to not overload the inputs
I use also QA101 Mixed Signal Oscilloscope
$409
and Tecktronics digital oscilloscope
I know my stuff "
OK I admit to not know these. My stuff is only Teccckkktronixxx etc.
Again, I do not completely understand, are we falling into a troll trap? Did I do tricky even freq. responses all the time without knowing it?
And the totally reasonable price of only $12,995 per pair! I gotta git me some of them!
Mike
Most equipment is built to a price point, and the sound is a result of that usually. Somebody probably thought it sounded better that way, a focus group or something.
Automotive is probably worse than consumer audio, where you see the shaving of fractions of pennies from a product that will be priced at $20k or more. The processors in car stereos are biased like you have described, as mentioned here before.
Automotive is probably worse than consumer audio, where you see the shaving of fractions of pennies from a product that will be priced at $20k or more. The processors in car stereos are biased like you have described, as mentioned here before.
The OP is perfectly correct.
Many of the mid/lower end amplifiers and receivers from the big brands in the 70s and 80s offered a 'tailored' response, in the 'flat' position, particularly boosting the lower mid-bass and often rolling off the extreme top end. I've measured hundreds over the years and often the results are far from the pretty little graphs of limited resolution we saw in the HiFi rags giving some of this junk "rave reviews". Bear in mind, the magazines in the 70s and 80s used tiny little FR plots in print with the vertical scale in coarse dB gradations. They'd gloss over the flaws and talk about the good stuff.
Now, FFT and accurate PC based test gear is available to anyone and the truth is easily seen.
The only brand I consistently saw flat FR curves was Harman Kardon gear from the 1980s. Their entire range, from the cheapest to the most expensive was to all intents and purposes, ruler flat from almost DC-daylight (just a saying).
Sansui were the worst in vintage with their little integrated and baby receivers posting plots that were a joke. Yamaha amps only started flattening out about 4 models up the range. Most tone controls at flat, completely butchered the FR unless a true bypass was fitted. Wait until you use a square wave and view how bad most amps of the vintage era were.
The HiFi magazines printed reviews that the manufacturers and the buying public want to hear- that there are bargains in the form of 'giant killers' and 'audiophillia on a budget' and 'best amplifer for <$300 etc' crap. (NAD, Marantz and half of the UK-made rat's-nests-in-a-tin amplifiers, I talking about you...)
Even the TOTL stuff wasn't free from slight response 'tweaking' but you were way more likely to find that $399 amplifier that you thought sounded sweet with a pair of $299 shoebox two-ways was in reality running a cheeky loudness contour, even when its tone controls were 'bypassed' or not even installed.
Many of the mid/lower end amplifiers and receivers from the big brands in the 70s and 80s offered a 'tailored' response, in the 'flat' position, particularly boosting the lower mid-bass and often rolling off the extreme top end. I've measured hundreds over the years and often the results are far from the pretty little graphs of limited resolution we saw in the HiFi rags giving some of this junk "rave reviews". Bear in mind, the magazines in the 70s and 80s used tiny little FR plots in print with the vertical scale in coarse dB gradations. They'd gloss over the flaws and talk about the good stuff.
Now, FFT and accurate PC based test gear is available to anyone and the truth is easily seen.
The only brand I consistently saw flat FR curves was Harman Kardon gear from the 1980s. Their entire range, from the cheapest to the most expensive was to all intents and purposes, ruler flat from almost DC-daylight (just a saying).
Sansui were the worst in vintage with their little integrated and baby receivers posting plots that were a joke. Yamaha amps only started flattening out about 4 models up the range. Most tone controls at flat, completely butchered the FR unless a true bypass was fitted. Wait until you use a square wave and view how bad most amps of the vintage era were.
The HiFi magazines printed reviews that the manufacturers and the buying public want to hear- that there are bargains in the form of 'giant killers' and 'audiophillia on a budget' and 'best amplifer for <$300 etc' crap. (NAD, Marantz and half of the UK-made rat's-nests-in-a-tin amplifiers, I talking about you...)
Even the TOTL stuff wasn't free from slight response 'tweaking' but you were way more likely to find that $399 amplifier that you thought sounded sweet with a pair of $299 shoebox two-ways was in reality running a cheeky loudness contour, even when its tone controls were 'bypassed' or not even installed.
Most test gear of yesteryear was CRT based and the only way to reproduce/store plots was to photograph (using a film camera) the scope or CRT display (as the HiFi magazines used to do). I'm sure you can understand why I don't have a vast repository of plots...
In the late 80s, early 90s, we had gear that could export basic BMPs (Dos/Win 3.11) or output to a plotter/dot matrix printer at 150-300dpi on fanfold tractor feed paper if you were lucky! Some exotic test gear produced fantastic thermal printouts that lasted about a month before fading I wish I had a AP System 1 but $30k+ for something that output a 640*480 CRT display and needed a 286/386 was out of reach. Funny, you can buy one now for $2k used, but it's useless- you need to maintain an ancient PC/AT machine to keep it going.
Now we can download myriad software, for free, utilise a 24/96 or above soundcard with front end noise levels 120dB+ down, pad down the front end and FFT/Sweep gear with higher resolution and accuracy than the HiFi mags could have dreamed of back in the 1970s/80s.
Yes, I have a relatively low opinion of most European HiFi gear of yesteryear. Newer stuff I don't see- probably because not much was sold here and it hasn't died yet maybe. I've spent far too much time repairing poorly designed, badly implemented, overpriced junk that was sold on the superlative riddled, subjective reviews of HiFi magazines that were pushing their advertising agendas to the detriment of their reader's bank balances.
I have an old piece of aquisition gear (AudioLab) from 1995 that I need to maintain a dedicated Pentium 100 Win95 machine to run it! It's a dinosaur, but useful. The software is DOS and needs direct port access for two serial ports and '95 is the last OS to allow it to work.
I gave up with believing printed HiFi reviews in the mid 80s when the blatant errors, omissions and plain BS got too much to bear. The UK and Australian HiFi press were simply shocking. The US mags were reasonably trustworthy and the German ones, I couldn't read anyway so I can't comment.
But anyone, who bought anything based on a 'review' was, in my opinion, fooling themselves.
In the late 80s, early 90s, we had gear that could export basic BMPs (Dos/Win 3.11) or output to a plotter/dot matrix printer at 150-300dpi on fanfold tractor feed paper if you were lucky!
Some exotic test gear produced fantastic thermal printouts that lasted about a month before fading I wish I had a AP System 1 but $30k+ for something that output a 640*480 CRT display and needed a 286/386 was out of reach. Funny, you can buy one now for $2k used, but it's useless- you need to maintain an ancient PC/AT machine to keep it going.Now we can download myriad software, for free, utilise a 24/96 or above soundcard with front end noise levels 120dB+ down, pad down the front end and FFT/Sweep gear with higher resolution and accuracy than the HiFi mags could have dreamed of back in the 1970s/80s.
Yes, I have a relatively low opinion of most European HiFi gear of yesteryear. Newer stuff I don't see- probably because not much was sold here and it hasn't died yet maybe. I've spent far too much time repairing poorly designed, badly implemented, overpriced junk that was sold on the superlative riddled, subjective reviews of HiFi magazines that were pushing their advertising agendas to the detriment of their reader's bank balances.
I have an old piece of aquisition gear (AudioLab) from 1995 that I need to maintain a dedicated Pentium 100 Win95 machine to run it! It's a dinosaur, but useful. The software is DOS and needs direct port access for two serial ports and '95 is the last OS to allow it to work.
I gave up with believing printed HiFi reviews in the mid 80s when the blatant errors, omissions and plain BS got too much to bear. The UK and Australian HiFi press were simply shocking. The US mags were reasonably trustworthy and the German ones, I couldn't read anyway so I can't comment.
But anyone, who bought anything based on a 'review' was, in my opinion, fooling themselves.
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