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How to understand the meaning of those measurement?

fxavier

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I am pretty new to this area, when I look through those review, I found that I couldn't understand the meaning of those testing. Is there anywhere that I can find an answer for that?

Below is a little notes I took after read an review, I want to figure out what outcome is ideal and what not for each test, and what happen when the outcome is ideal and what happen when it not.

1. RMS Level (Vrms)
2. TND+N Ratio (%)
3. Frequency (kHz)
4. SINAD (dB)

• e.g output: ASIO: ASIO4ALL v2.2 Chs, 44.1 kHz
• e.g input: Analog Balanced 2 Ch., 200 kohm, 2.5 Vrms, AC (<10 Hz) - 22.4kHz
5. Dynamic range (dB)
* above measurement measure in both ch1&2

6. Output
- balance / unbalanced

7. Scope
- instantaneous Level (V) x Time (s)

8. FFT
- Frequence (Hz) x Level (dBrA)

9. Intermodulation distortion
- e.g 60 Hz and 7 kHz signals
- SMPTE/DIN ratio (dB) x Generator Level (dBFS)
- lower better

10. Multitone test
- e.g 32 Tone input Signal / 192 kHz Sampling Rate
- Level (dBrA) x Frequency (Hz)

11. Jitter measurements
- e.g Jitter Noise and Spectrum 256k Point FFT, 16 Averages
- Level (dBrA) x Frequency (Hz)

12. FFT Spectrum of White Noise
- e.g 44.1 KHz Sampling
- Level (dBrA) x Frequency (Hz)

13. Linearity
- Relative Level (dB) x Generator Level (dBFS)
- 0dB Relative Level is best

14. THD+N versus frequency
- e.g 48 kHz
- THD+N Ratio (%) x frequency (Hz)
- e.g wide band (90 kHz) determines how much of the unwanted ultrasonic are let through

15. Power x Distortion
- e.g 30 Ohm, 300 Ohm
- THD+N Ratio (dB) x W
- THD+N Ratio (dB) x Voltage (Vrms)
 
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fxavier

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is there anyone that can help me out? or is there any article that I can read?
 

tonycollinet

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You are asking for an understanding of detailed technical topics. You are going to have to do a lot of reading. A good place to start is this thread:

https://www.audiosciencereview.com/...ng-for-new-comers-and-inquisitive-minds.8121/

I good place to ask questions is in the beginners forum:
https://www.audiosciencereview.com/forum/index.php?forums/audio-newbie-beginner-technical-forum.46/

I would suggest looking into one topic at a time, and getting an understanding of that before moving on - starting with voltage and power and how they are measuired (EG your Vrms question above, how power is measured (what is a dB) etc.). Without understanding the basics (eg units of measure) you are not going to be able to understand any of the measurements.
 

abdo123

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Basically every analog device outputs a signal, the signal has an amplitude that is measured in Volts.

it’s easy to think of RMS as ‘average’ so Vrms is ‘average voltage of the output signal at a particular situation’

Noise is well the noise you hear coming out of a speaker’s tweeter when your devices are turned on but nothing is actually playing

it usually defined as a ratio of the signal to noise in volts or dB.

for example, if 2 volts of signal contain 1 volts of residual noise then the Signal to Noise (S/N) ratio or Dynamic Range is 6 dB.

Every signal generator produces some amount of distortion along the intended signal.

One type of distortion, harmonic distortion, is easily measured and compared between devices, it’s better to search on Youtube or something to understand more clearly what harmonic distortion is as it is not a simple thing to explain in typing.

THD+N is the addition of both noise and total harmonic distortion (either in volts. or in in relation to the output signal)

SINAD is THD+N % but in dB terms instead of % terms.
 
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fxavier

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It seems I need to understand the measurement itself first instead of knowing how to measure it. I will look into that after I learn the measurement. Thank you!

You are asking for an understanding of detailed technical topics. You are going to have to do a lot of reading. A good place to start is this thread:

https://www.audiosciencereview.com/...ng-for-new-comers-and-inquisitive-minds.8121/

I good place to ask questions is in the beginners forum:
https://www.audiosciencereview.com/forum/index.php?forums/audio-newbie-beginner-technical-forum.46/

I would suggest looking into one topic at a time, and getting an understanding of that before moving on - starting with voltage and power and how they are measuired (EG your Vrms question above, how power is measured (what is a dB) etc.). Without understanding the basics (eg units of measure) you are not going to be able to understand any of the measurements.
Sorry I didn't know there is a beginner section. I should have ask there. It has bothering me awhile for reading those review just to skip ahead to the conclusion. I know it got some learning curve and I am willing to spend the time to learn more about it. Thank you.

This looks exactly what I need, THANK YOU!
 

KenTajalli

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Sep 8, 2021
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I am pretty new to this area, when I look through those review, I found that I couldn't understand the meaning of those testing. Is there anywhere that I can find an answer for that?

Below is a little notes I took after read an review, I want to figure out what outcome is ideal and what not for each test, and what happen when the outcome is ideal and what happen when it not.

1. RMS Level (Vrms) (since alternating electricity AC is constantly changing, The RMS value gives an equivalent DC value, so 3V RMS AC has as much juice in it as 3V DC!)
2. TND+N Ratio (%) ( this is everything is added to the signal once it goes through a device as a fraction of the signal - the less the better)
3. Frequency (kHz) ( how many times a second a signal changes, 1 kHz means a 1000 times a second)
4. SINAD (dB)
(There is a definition for it, but I don't understand it fully either)
• e.g output: ASIO: ASIO4ALL v2.2 Chs, 44.1 kHz ( Has nothing to do with SINAD , these are different methods two devices talk to each other)
• e.g input: Analog Balanced 2 Ch., 200 kohm, 2.5 Vrms, AC (<10 Hz) - 22.4kHz (Again nothing to do with SINAD, these are specific requirements of certain devices)
5. Dynamic range (dB) ( the difference between the highest and lowest level a device can manage before it looses the plot - measure in deci bells)
* above measurement measure in both ch1&2 ( two measurements done, one for one channel (stereo) and another for the other channel, to compare)

6. Output
- balance / unbalanced ( signal is output ed by two wires, unbalanced means one wire is at zero and the other wire's voltage varies with signal - Balanced means both wire's voltage vary with signal, but in opposite to each other, so it sort of pushes and pulls against the other)

7. Scope
- instantaneous Level (V) x Time (s) ( a device to see an electrical waveform voltage against time)

8. FFT
- Frequence (Hz) x Level (dBrA) (fast fourier transform, a mathematical algorithm that mixes and seperates different frequencies, phases)

9. Intermodulation distortion ( a type of unwanted distortion when two or more signals interact within a device )
- e.g 60 Hz and 7 kHz signals
- SMPTE/DIN ratio (dB) x Generator Level (dBFS)
- lower better

10. Multitone test ( testing a device with not just one pure frequency but with multiple at the same time)
- e.g 32 Tone input Signal / 192 kHz Sampling Rate
- Level (dBrA) x Frequency (Hz)

11. Jitter measurements ( jitter is a type distortion that occurs in digital to analogue converters, when the timing (frequency) of a reproduced signal jitters! so there is the signal, but also there are little other signals a little higher in frequency and a little lower in frequency)
- e.g Jitter Noise and Spectrum 256k Point FFT, 16 Averages
- Level (dBrA) x Frequency (Hz)

12. FFT Spectrum of White Noise ( see FFT above, white noise is a signal that has all the frequencies (within a range) bundled together and at same level, using FFT the output can be measured to see if all those frequencies come out the same)
- e.g 44.1 KHz Sampling
- Level (dBrA) x Frequency (Hz)

13. Linearity ( if the signal level goes up by %10 the output should go up by %10, if it does it is linear, if it deviates it is not)
- Relative Level (dB) x Generator Level (dBFS)
- 0dB Relative Level is best

14. THD+N versus frequency ( total harmonic distortion + noise , is a measurement to see how that changes according to what signal is being used)
- e.g 48 kHz
- THD+N Ratio (%) x frequency (Hz)
- e.g wide band (90 kHz) determines how much of the unwanted ultrasonic are let through

15. Power x Distortion ( do you mean Power multiplied by distortion ??)
- e.g 30 Ohm, 300 Ohm
- THD+N Ratio (dB) x W
- THD+N Ratio (dB) x Voltage (Vrms)

Expand the above to see answers.
I had a go, tried to keep the answers as simple as I could.
Learning the vocabulary of a new language, is only the first step.
 
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