THD has a much bigger effect on sound than you think

[solderdude]

Can I ask what the goal of the exercise is ?
Do you plan to use tones or music ?
Do you want to know how this amp sounds near full power or at more sensible levels where it would be used ?
When you go for the max distortion emulation then music signals that are not nearing even 1 W will also have high amounts of distortion which in reality won't be the case. It will be a lot better.
In reality distortion levels are ONLY this high near clipping levels and are much more favorable at lower levels where it would be used with sensitive speakers.

At 5W:
H2= -32
H3= -44
H4= -58
H5= -68
H6= -80
H7= -88
H8= -100

At 2W:
H2= -45
H3= -64
H4= -84
H5= -84
H6= -104
H7= -96
H8= -118

At 1W:
H2= -50
H3= -72
H4= -95
H5= -103
H6= -134
H7= -120
H8= -125

You see the harmonics change depending on level. Peaks in music are short and usually contain higher harmonics the moment a tone is 'hit' and then drops quickly by many dB so from 5W to 0.5W or 0.05W in a matter of ms.

And just to be clear. None of the above settings will emulate the ACA's actual sound. So even when you test it the actual ACA will sound different.
As Paul mentioned. Distort is not designed to emulate amps only to distort a signal in a pre-defined way.

Use music.. not test tones !!!

 

[Pdxwayne]

Can I ask what the goal of the exercise is ?
Do you plan to use tones or music ?
Do you want to know how this amp sounds near full power or at more sensible levels where it would be used ?
When you go for the max distortion emulation then music signals that are not nearing even 1 W will also have high amounts of distortion.
In reality distortion levels are ONLY this high near clipping levels and are much more favorable at lower levels where it would be used with sensitive speakers.

At 5W:
H2= -32
H3= -44
H4= -58
H5= -68
H6= -80
H7= -88
H8= -100

At 2W:
H2= -45
H3= -64
H4= -84
H5= -84
H6= -104
H7= -96
H8= -118

At 1W:
H2= -50
H3= -72
H4= -95
H5= -103
H6= -134
H7= -120
H8= -125

Use music.. not test tones !!!

What would be your estimate for 7 watts? Lets still using test tone for now for simplicity. What numbers should I plugged in when I have a 0db tone?

1,2,5, or 7 watts?

BTW, test files are available for you at

250hz_h2_to_h4_120_h5_60.wav and 1 more file

2 files sent via WeTransfer, the simplest way to send your files around the world

we.tl

; )

 

[pkane]

At least point me to a few good sites for learning please?

Google can help you.

 

[Lambda]

If the transfer function for a amp or amp + speaker is Known why don’t we crate an inverse of this in DSP and cancel the distortion?

Seems to work in RF PAs

 

[pma]

If the transfer function for a amp or amp + speaker is Known why don’t we crate an inverse of this in DSP and cancel the distortion?

Seems to work in RF PAs

Because it is not so simple in real life amplifiers. The transfer function is not only a function of level, but also of frequency (sometimes very heavily) and also of load impedance. This would be my question to @pkane, Paul, would you be able to implement frequency as a further variable in the Distort??

And, we already have a solution in Microcap or LTSpice. Both can work above wav input with transfer function that is close to reality. It is only time consuming for computer time. Music can be used as an input. But it needs much more competent knowledge of electronic circuits than a beginner approach.

 

[Pdxwayne]

Google can help you.

So, I read some web pages. Not something I am that interested in learning. Math was too boring for me and thus I didn't take anything more than 2nd years college calculus.

Anyway, I still don't know why you keep insisting for me to learn about transfer function. How would it tell me what distortion numbers to use when I run a file through your app?

Again, here are the numbers. How would knowing transfer function letting me decide what distortion numbers to enter into your app?


At 5W:
H2= -32
H3= -44
H4= -58
H5= -68
H6= -80
H7= -88
H8= -100

At 2W:
H2= -45
H3= -64
H4= -84
H5= -84
H6= -104
H7= -96
H8= -118

At 1W:
H2= -50
H3= -72
H4= -95
H5= -103
H6= -134
H7= -120
H8= -125

 

[solderdude]

What would be your estimate for 7 watts? Lets still using test tone for now for simplicity. What numbers should I plugged in when I have a 0db tone?

1,2,5, or 7 watts?

The problem is the values below are taken with a cold amp and are not representative for 5W under warmed up conditions.

At 5W (cold start):
H2= -32
H3= -44
H4= -58
H5= -68
H6= -80
H7= -88
H8= -100

guesstimate at 5W warmed up:

H2= -43
H3= -55
H4= -70
H5= -75
H6= -95
H7= -90
H8= -110

It will be the following numbers around 8W (warmed up)

H2= -32
H3= -44
H4= -58
H5= -68
H6= -80
H7= -88
H8= -100

As said before the numbers you punch in will NOT represent the amp with music. You will hear distortion with a pure sine wave.
You cannot emulate this amp with distort using music.

When you want you need to do tests with 1W values and 5W warmed up values and perhaps 8W warmed up values.
This will tell you absolute nothing about how it will sound in realty, also not when using music.
As you can see in the plots at 50mW the distortion will be predominantly 2nd harm and that one will be be around -62dB and 3rd around -80dB.
When you would use distort set at 5W warmed up and dial down the volume of the amp H2 would still be -43 while the real amp would be just -62.

So... whatever setting you use you are not emulating the ACA.

 

[Pdxwayne]

The problem is the values below are taken with a cold amp and are not representative for 5W under warmed up conditions.

At 5W (cold start):
H2= -32
H3= -44
H4= -58
H5= -68
H6= -80
H7= -88
H8= -100

guesstimate at 5W warmed up:

H2= -43
H3= -55
H4= -70
H5= -75
H6= -95
H7= -90
H8= -110

It will be the following numbers around 8W (warmed up)

H2= -32
H3= -44
H4= -58
H5= -68
H6= -80
H7= -88
H8= -100

As said before the numbers you punch in will NOT represent the amp with music. You will hear distortion with a pure sine wave.
You cannot emulate this amp with distort using music.

So if you are using pkane's app, which distortion series would you use?

 

[peng]

So, I read some web pages. Not something I am that interested in learning. Math was too boring for me and thus I didn't take anything more than 2nd years college calculus.

Anyway, I still don't know why you keep insisting for me to learn about transfer function. How would it tell me what distortion numbers to use when I run a file through your app?

You are right, in that It won't be easy to learn what pkane may be suggesting but then I am not really sure exactly what he expects you to learn. A degreed EE would have studied advanced calculus, infinite series, Laplace, Fourier and other transforms, those specialized in communications and control systems would have an advantage. Aside from transfer functions, imo one needs to have a good understanding of Fourier series/transform, to understand harmonic analysis, and that typically wouldn't be covered in second year college, may be third..

 

[solderdude]

So if you are using pkane's app, which distortion series would you use?

Depends on the goal of the test. When it is to find out how a single tone will sound at a specific power level use those settings. Try 1W and 8W for instance.

Other than that I would not use distort to emulate that amp with music. It is not designed to do this. You would have to enter the transfer curve.

 

[pkane]

You are right, in that It won't be easy to learn what pkane may be suggesting but then I am not really sure exactly what he expects you to learn. A degreed EE would have studied advanced calculus, infinite series, Laplace, Fourier and other transforms, those specialized in communications and control systems would have an advantage. Aside from transfer functions, imo one needs to have a good understanding of Fourier series/transform, to understand harmonic analysis, and that typically wouldn't be covered in second year college, may be third..

The problem is @Pdxwayne is making public statements and assumptions about amps, distortion, software, and audibility that he’s not qualified to make. I’ve tried to correct his assumptions, but he keeps insisting on arguing from an uneducated point of view. As I said, I’m not here to teach, as I really don’t have the patience for those who are unwilling to do some homework.

 

[Pdxwayne]

The problem is @Pdxwayne is making public statements and assumptions about amps, distortion, software, and audibility that he’s not qualified to make. I’ve tried to correct his assumptions, but he keeps insisting on arguing from an uneducated point of view. As I said, I’m not here to teach, as I really don’t have the patience for those who are unwilling to do some homework.

Ok. Your app could not make good sounding files when using "stereo" option to save. Did you check that out? Or is it all the fault of uneducated user?

 

[pkane]

Ok. Your app could not make good sounding files when using "stereo" option to save. Did you check that out? Or is it all the fault of uneducated user?

the latter, of course

 

[Pdxwayne]

the latter, of course

Well, this will be your last app feedback from an unhappy customer.

: P

 

[pma]

So, I read some web pages. Not something I am that interested in learning. Math was too boring for me and thus I didn't take anything more than 2nd years college calculus.

Anyway, I still don't know why you keep insisting for me to learn about transfer function. How would it tell me what distortion numbers to use when I run a file through your app?

If you want to be a partner in a discussion, you need to study something like this

https://web.mit.edu/6.101/www/reference/op_amps_everyone.pdf

and have knowledge at this level.
It is impossible to have a meaningful discussion between amateur enthusiast who is unwilling to learn and bored with math and the qualified people who have university degree and spent tens of years in the field. If there is a scientific symposium it is not attended by the people who just came around. If there is someone willing to learn and it can be seen from the posts, then it may make sense to try to teach. Otherwise, it is a lost time and similar crowds would soon appear.

 

[Killingbeans]

No not joking. When I made statements in my other threads, many would ask me to do actual blind tests, do abx, etc. So, fair game I do the same to someone who made an "everyone can hear" statement.

No offence, but I think you've misunderstood the concept of critical thinking.

You do blind tests to verify observations that go against all known empirical evidence. If the observation is already supported by empirical evidence, it becomes pointless to do blind tests. If I tell you that it would hurt if I smacked you in the face with a hammer, will you insist on doing a blind test to verify it?

 

[Pdxwayne]

If you want to be a partner in a discussion, you need to study something like this

https://web.mit.edu/6.101/www/reference/op_amps_everyone.pdf

and have knowledge at this level.
It is impossible to have a meaningful discussion between amateur enthusiast who is unwilling to learn and bored with math and the qualified people who have university degree and spent tens of years in the field. If there is a scientific symposium it is not attended by the people who just came around. If there is someone willing to learn and it can be seen from the posts, then it may make sense to try to teach. Otherwise, it is a lost time and similar crowds would soon appear.

I asked simple question for what distortions number to use to enter in your app. You asked for me to take classes that I am not interested in.

Fair attitude for first time user of your app?

 

[Pdxwayne]

No offence, but I think you've misunderstood the concept of critical thinking.

You do blind tests to verify observations that go against all known empirical evidence. If the observation is already supported by empirical evidence, it becomes pointless to do blind tests. If I tell you that it would hurt if I smacked you in the face with a hammer, will you insist on doing a blind test to verify it?

Sorry. Again, words. This is not the way of ASR.

Action please. Files available for you to prove your point:

250hz_h2_to_h4_120_h5_60.wav and 1 more file

2 files sent via WeTransfer, the simplest way to send your files around the world

we.tl

Share your ABX results here.

 

[pkane]

I asked simple question for what distortions number to use to enter in your app. You asked for me to take classes that I am not interested in.

Fair attitude for first time user of your app?

I think you’re confused.

 

[pkane]

Well, this will be your last app feedback from an unhappy customer.

: P

already offered you a full refund!