Nobody wants to know if you hear distortion.
But
Do you measure distortion?
I thought about what a measurement experiment could look like so that the person measuring can directly experience what they are currently doing and achieving.
Do you have a speaker? Good!
Have you ever measured the frequency response of your speaker? Good!
Can you connect a line directly to a transducer in it (leave out the crossover)? Good!
Find a resistor with 20R! Don't worry about the power performance of this resistor! Just keep explosives, your beautiful toddler, your cat... away! 10 Watts is what i use. That's plenty and certainly a lot more than my speaker can handle.
Complete your usual measurement setup.
Carry out a measurement at a very moderate volume. Only the transducer in the box, directly connected to the amplifier. [1]
Save this measurement to overlay. [1]
Then insert the 20R resistor. In series to the transducer. Carry out a second measurement. Increase the volume to approximately the same sound pressure level. [3]
This is all about distortion. So RTFM until you have two distortion charts.
[4] One connected directly and one with the 20R in series.
If you do not see a difference in D3 ask here for help.
This was done at 0,5 Volts at the transducer:
No need to blast your speaker!
[1] yellow is the fundamental directly connected (0R)
[2] Same setup, just disconnected speaker. Noise...
[3]
green is with 20R in series.
yellow is directly connected (from [1])
[4]
D3o (white) is directly connected (0R)
D3 (red) is with 20R in series
20240108 Edit 1:
I am extremely disappointed by the fact that no one is taking measurements here on diyAudio. There are only theoretical heroes here who type more or less gross nonsense with their keyboard.
20240108 Edit 2:
User >OllBoll< on diyAudio was the first measuring "it".
https://www.diyaudio.com/community/threads/hypex-ncore.190434/page-384#post-4095122
He was cited on a German forum on
12.09.2023, 16:47
9 years (nine years !) later, because there was nobody on the whole internet measuring "it". Now that
Tenson< joined,
https://www.diyaudio.com/community/...ortion-measurement.402566/page-9#post-7558653
we are 3. Please be the 4th ;-)
20240110 Edit 3:
tmuikku< joined (#40), we are 4. please be the 5th ;-)
But
Do you measure distortion?
I thought about what a measurement experiment could look like so that the person measuring can directly experience what they are currently doing and achieving.
Do you have a speaker? Good!
Have you ever measured the frequency response of your speaker? Good!
Can you connect a line directly to a transducer in it (leave out the crossover)? Good!
Find a resistor with 20R! Don't worry about the power performance of this resistor! Just keep explosives, your beautiful toddler, your cat... away! 10 Watts is what i use. That's plenty and certainly a lot more than my speaker can handle.
Complete your usual measurement setup.
Carry out a measurement at a very moderate volume. Only the transducer in the box, directly connected to the amplifier. [1]
Save this measurement to overlay. [1]
Then insert the 20R resistor. In series to the transducer. Carry out a second measurement. Increase the volume to approximately the same sound pressure level. [3]
This is all about distortion. So RTFM until you have two distortion charts.
[4] One connected directly and one with the 20R in series.
If you do not see a difference in D3 ask here for help.
This was done at 0,5 Volts at the transducer:
No need to blast your speaker!
[1] yellow is the fundamental directly connected (0R)
[2] Same setup, just disconnected speaker. Noise...
[3]
green is with 20R in series.
yellow is directly connected (from [1])
[4]
D3o (white) is directly connected (0R)
D3 (red) is with 20R in series
20240108 Edit 1:
I am extremely disappointed by the fact that no one is taking measurements here on diyAudio. There are only theoretical heroes here who type more or less gross nonsense with their keyboard.
20240108 Edit 2:
User >OllBoll< on diyAudio was the first measuring "it".
https://www.diyaudio.com/community/threads/hypex-ncore.190434/page-384#post-4095122
He was cited on a German forum on
12.09.2023, 16:47
9 years (nine years !) later, because there was nobody on the whole internet measuring "it". Now that
Tenson< joined,
https://www.diyaudio.com/community/...ortion-measurement.402566/page-9#post-7558653
we are 3. Please be the 4th ;-)
20240110 Edit 3:
tmuikku< joined (#40), we are 4. please be the 5th ;-)
Last edited:
Where is the resonant frequency? The levels should be quite unequal around resonance unless your gain correction depends on frequency.
Where is the resonant frequency of your loudspeaker?
Where are the levels of your Loudspeaker?
I have neither the equipment nor the desire to do such a measurement. My reply was from before you made edit 1, otherwise I would not have replied at all.
PMA did several loudspeaker distortion measurements under current drive - which is not exactly the same as 20 ohm drive, but the trends were similar.
Coming back to Marcel's point: I would expect to clearly see the speaker resonance with the 20R drive on the freq response.
There's no sign of it, which makes the measurement suspect.
Not against measurments - on the contrary, without measurements you know nothing.
I am always measuring my projects.
But this is very strange. Or did you do some kind of pre-correction?
Jan
There's no sign of it, which makes the measurement suspect.
Not against measurments - on the contrary, without measurements you know nothing.
I am always measuring my projects.
But this is very strange. Or did you do some kind of pre-correction?
Jan
Wy did you use dB in the first distortion presentation and % in the second?
//
//
Welcome.
I have the equipment and do measure, but I’m occupied with designing other things at this time.
Plot starts at 100Hz, resonance is probably below 30Hz. With 20R the increase in Q may be moderate. I think we see signs of response starting to rise at 100Hz. Lot's of guesswork.
Rather than providing clarification to our questions the OP chose to be snarky and condescending in his usual style.
I fear this thread is doomed.
No, you should all please accept the measurement challenge and show your measurements ;-)
Are those who have the equipment and time to do the measurement to start their measurement well above, at or well below resonance?
@Hörnli Is not your point(s) already made here?
https://www.diyaudio.com/community/threads/drive-current-distortion-measurement.402566/post-7438273
https://www.diyaudio.com/community/threads/drive-current-distortion-measurement.402566/post-7438273
Just define the range of interest freely for yourself. STEPS allows to define a range. Sometimes i define a small range to save time. Especially if i use 1/48 octave steps for finer detail.
No, my point here is LRDDMC (#1). Your measurement is missing here.
Last edited:
I guess what @Hörnli wants to do is gather a wider range of evidence because for example my data is only with one driver (nd91-4).
I don't really understand why I should repeat this measurement.
Do you need confirmation?
It is anyway hard to replicate your measurement because there is no information about what exactly you did.
No measurement setup, connections, used amplifier/speaker, and as noted the results you gave bring up more questions than it answers.
You refuse to answer reasonable questions, so I don't think people will drop what they are doing to do - what exactly?
Jan
Do you need confirmation?
It is anyway hard to replicate your measurement because there is no information about what exactly you did.
No measurement setup, connections, used amplifier/speaker, and as noted the results you gave bring up more questions than it answers.
You refuse to answer reasonable questions, so I don't think people will drop what they are doing to do - what exactly?
Jan