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Stuart Charles here, HomeStudioBasics.com helping YOU make sound decisions, so…
Amidst the flashy jargon and high-tech buzzwords that dominate discussions about audio equipment, certain unassuming terms often find themselves relegated to the background.
One such term is the “Signal-to-Noise Ratio” or SNR.
Despite its unglamorous demeanor, this metric holds a pivotal role in the world of audio quality; perhaps the most important when considering the role that Amps and DACs play in audio.
Forewarning: We’re going to math in this article, so proceed with caution. xD
In this brief exploration, we shed light on the importance of SNR, showcasing how seemingly overlooked elements can wield significant influence in the realm of sound.
Signal-to-Noise Ratio (SNR) is a metric used to quantify the quality of an audio signal in relation to the background noise present in the signal.
In the context of headphone amplifiers (amps), SNR is an important specification that indicates how clean and clear the amplified audio signal will be when it reaches the headphones.
In technical terms, SNR is the ratio of the amplitude of the desired audio signal (the “signal”) to the amplitude of the unwanted background noise (the “noise”).
It’s typically measured in decibels (dB), which is a logarithmic unit that expresses the relative difference between two values.
For example, if a headphone amp has an SNR of 100 dB, it means that the level of the audio signal is 100 dB higher than the level of the background noise generated by the amplifier itself.
A higher SNR value indicates a better signal quality because the audio signal is more distinguishable from the noise, resulting in cleaner and clearer sound.
In headphone amplifiers, a high SNR is desirable because it ensures that the sound you hear through your headphones is faithful to the original audio source without being degraded by added noise.
Lower-quality headphone amps might have a lower SNR, leading to a noticeable hiss or static in the audio playback, especially during quiet passages or when the volume is turned up.
How To Calculate SNR
The Signal-to-Noise Ratio (SNR) can be calculated using the following formula:
SNR (in decibels) = 20 * log10 (Signal Amplitude / Noise Amplitude)
Here’s what each component represents:
- Signal Amplitude: This is the amplitude or strength of the desired signal that you want to measure the SNR for. It’s usually measured in the same units as the noise amplitude.
- Noise Amplitude: This is the amplitude of the background noise that is present in the signal. It’s typically measured in the same units as the signal amplitude.
The logarithm base 10 (log10) function is used to convert the ratio into a logarithmic scale, which is commonly used for SNR measurements in decibels (dB).
Example
- Calculate the Ratio:
- Divide the Signal Amplitude by the Noise Amplitude.
- Let’s call this ratio “R”.
- R = Signal Amplitude / Noise Amplitude
- Calculate the log10 of the Ratio:
- Use the log10 function to find the logarithm (base 10) of the ratio “R”.
- log10(R) = logarithm base 10 of ratio “R”
- Multiply by 20:
- Multiply the result from step 2 by 20 to convert it into decibels.
- SNR (in decibels) = 20 * log10(R)
In mathematical notation, you would represent this as:
SNR (in decibels) = 20 * log10(Signal Amplitude / Noise Amplitude)
Here’s an example of using actual values:
Let’s say Signal Amplitude = 100 and Noise Amplitude = 10.
- Ratio (R) = Signal Amplitude / Noise Amplitude = 100 / 10 = 10
- log10(R) = log10(10) = 1
- SNR (in decibels) = 20 * log10(R) = 20 * 1 = 20 dB
So, in this example, the SNR is 20 decibels.
One thing to keep in mind is that the Logarithm base 10 of 10 is 1. This is because the logarithm of a base raised to its own power is 1.
In other words, log10(10) = 1.
This means that 10 raised to the power of 1 equals 10.
So, when you calculate log10(10), the result is 1.
If the R number was something different, like 5 for instance, you’d just use the log function on a calculator:
- Enter 5.
- Press the “log” button.
- The calculator will display the result, which is approximately 0.69897.
- So SNR (in decibels) = 20 * log10(R) = 20 * 0.69897 ≈ 13.9794 dB
Remember that when using this formula, both the signal amplitude and the noise amplitude should be measured using the same units.
Also, the larger the resulting SNR value in dB, the better, as it indicates a stronger signal relative to the noise.
Note: If the signal amplitude or the noise amplitude is measured in terms of power rather than amplitude, the formula would involve calculating the ratio of power rather than amplitude. In that case, the formula would be:
SNR (in decibels) = 10 * log10 (Signal Power / Noise Power)
Here, the 10 multiplier is used instead of 20 since power ratios are inherently squared (because power is proportional to the square of amplitude).
Closing Thoughts
In the realm of audio technology, the Signal-to-Noise Ratio (SNR) might lack the spotlight, yet its significance is incredibly important.
This unassuming metric holds the power to distinguish between the desired audio signal and the unwanted background noise.
Through its logarithmic calculation, SNR ensures that the sounds we hear through our devices are clear, devoid of distortion, and faithfully represent the intended audio.
Amidst the glitz of advanced features, SNR silently safeguards the purity of our auditory experiences, proving that even the subtlest of factors can wield a profound impact on the quality of sound we encounter.
When considering headphone amps, it’s important to pay attention to the SNR specification to make an informed decision about the quality of audio you can expect from the amplifier.
The SINAD Standard And Why It’s So Important
Well, that’s about it for today folks! I hope you’ve enjoyed this What is Signal To Noise Ratio? discussion and gained some valuable insight.
Questions? Comments? Requests? Did I miss the mark on something? Please let me know down below or Contact me!!
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How important is SNR to you? I’d love to hear from you. Until next time…
All the best and God bless,
-Stu