What Is Microphone Self-Noise? Why Does It Matter for Recording?
Microphone self-noise (equivalent noise) refers to the inherent background noise generated by the microphone itself. This article provides a detailed explanation of the definition of self-noise, measurement methods, and acceptable ranges for various recording scenarios, helping recording beginners and podcasters choose the right microphone.
What Is Microphone Self-Noise? Why Does It Matter for Recording?
Have you ever noticed this? You’re recording in a quiet room, yet there’s still a faint “hiss…” in the background—something between electrical noise and the sound of air. You assume your microphone is defective, replace it with another one, and even try an expensive “noise-canceling microphone,” only to hear the same thing.
Don’t worry—it’s probably not a faulty microphone, nor is your room necessarily noisy.
What you’re hearing may actually be the microphone itself.
This inherent background noise produced by a microphone is called self-noise (also known as equivalent noise). Think of it like the grainy image your smartphone camera produces in low light—it’s a natural limitation of electronic devices.
In this article, we’ll explain:
- What microphone self-noise actually is
- Why it affects recording quality
- Whether it’s something you should really worry about
The Short Answer: What Does Self-Noise Mean?
Simply put, self-noise is the level of noise generated by the microphone itself when there is no sound being recorded.
It is measured in dBA (A-weighted decibels).
- Lower numbers = quieter microphone
- Higher numbers = more audible background hiss
You’ll usually find one of these specifications on a microphone’s datasheet:
- Equivalent Noise Level
- Self-Noise
- Signal-to-Noise Ratio (SNR)
As a general rule:
- Lower self-noise is better (under 10 dBA is excellent)
- Higher SNR is better (over 80 dB is considered good)
However, self-noise is only one factor when choosing a microphone. A lower number doesn’t automatically mean it’s the best microphone for your needs.
Why Do Microphones Have Self-Noise?
Every electronic component generates a tiny amount of electrical noise while operating.
Inside a microphone, components such as:
- the diaphragm
- preamp circuitry
- resistors
- capacitors
- transistors
all produce microscopic electrical fluctuations due to thermal motion and other physical phenomena.
These tiny signals are amplified together with your voice and become part of the recording.
Technical Definition
Equivalent Noise Level (EIN)
According to IEC 60268-4, equivalent noise is the A-weighted noise level measured in an anechoic chamber with no acoustic input. The unit is dBA.
Signal-to-Noise Ratio (SNR)
SNR measures the ratio between the desired audio signal and the microphone’s own noise.
A higher SNR means:
- cleaner recordings
- less background hiss
- better dynamic range
A Simple Analogy
Imagine your microphone is a recording studio.
Even when nobody is speaking, the room still contains tiny sounds:
- air conditioner hum
- computer fans
- subtle mechanical vibrations
These sounds never disappear completely.
A microphone’s self-noise works the same way.
When you’re speaking loudly, your voice easily masks it.
But during pauses, whispers, or quiet passages, the background hiss becomes noticeable.
Understanding the Key Specifications
1. Equivalent Noise (dBA)
Typical ranges are:
- 6–10 dBA — Extremely low self-noise; ideal for ASMR, whisper recording, and high-gain applications.
- 10–15 dBA — Excellent; suitable for podcasts, voice-over work, narration, and most instruments.
- 15–20 dBA — Acceptable; works well with some attention to gain staging and recording environment.
- Above 20 dBA — More noticeable in quiet recordings and may introduce obvious hiss.
2. Signal-to-Noise Ratio (SNR)
Typical microphones offer:
70–90 dB SNR
Generally speaking:
- Higher SNR = Lower self-noise
For example:
- 80 dB SNR ≈ 14 dBA equivalent noise
- Good enough for general voice recording
- Not ideal for extremely quiet recordings
3. A-Weighted vs. Unweighted Measurements
Most manufacturers publish A-weighted (dBA) measurements.
A-weighting reflects how human hearing responds to different frequencies by giving less emphasis to very low and very high frequencies.
As a result, A-weighted numbers usually appear more favorable and are more representative of real-world listening.
How Self-Noise Affects Recording Quality
1. It Raises the Noise Floor
When recording quiet sounds such as:
- whispers
- narration
- breathing
- acoustic guitar harmonics
- instrument decay
self-noise can cover fine details like a thin layer of fog.
Subtle nuances become harder to hear.
2. It Reduces Dynamic Range
Dynamic range depends heavily on the relationship between signal and noise.
Higher self-noise means:
- lower SNR
- reduced dynamic range
- recordings that sound less open and less detailed
3. Noise Reduction Isn’t a Perfect Solution
Many beginners think:
> “I’ll just remove the hiss in post.”
Unfortunately, that’s only partially true.
Noise reduction plugins work by suppressing frequencies identified as noise.
If pushed too far, they often introduce:
- metallic artifacts
- unnatural voices
- hollow sound
- loss of detail
Noise reduction should be viewed as damage control, not a replacement for clean recording.
Capturing a clean signal from the start is always the better approach.
Common Misconceptions
Myth 1: Lower Self-Noise Always Means Better Sound
Not necessarily.
Self-noise measures only one aspect of microphone performance.
A microphone with 8 dBA self-noise but a cold, thin sound may be less suitable for podcasting than one with 14 dBA self-noise but a warm, rich tone.
Other factors also matter:
- frequency response
- tonal character
- sensitivity
- polar pattern
- maximum SPL
Myth 2: Noise-Canceling Microphones Eliminate Self-Noise
No.
Most “noise-canceling microphones” use DSP algorithms to reduce external environmental noise after the sound has already been captured.
They cannot eliminate the microphone’s own electronic noise.
A noise-canceling microphone is not necessarily a low self-noise microphone.
Myth 3: Expensive Microphones Always Have Lower Self-Noise
Not always.
Many legendary vintage-style condenser microphones intentionally prioritize tonal character over ultra-low noise.
Likewise, dynamic microphones often have simpler electronics, but because they require much more gain, the preamp’s noise may become more noticeable.
Ultimately, what matters is whether the microphone performs well in your intended recording environment.
Recommended Self-Noise by Recording Scenario
| Recording Scenario | Recommended Self-Noise | Why |
|---|---|---|
| Podcasting / Voice-over | Below 15 dBA (ideally under 10 dBA) | Clean background during speech |
| Acoustic guitar, piano, violin | Below 12 dBA | Preserves delicate harmonics |
| ASMR, whispering, meditation | Below 10 dBA (preferably around 8 dBA) | High gain amplifies every tiny noise |
| Drums, rock vocals, guitar cabinets | Below 20 dBA is usually sufficient | Loud sources naturally mask microphone noise |
These are general recommendations. Actual requirements depend on the recording environment, musical style, and production goals.
How to Find a Microphone’s Self-Noise Specification
Look for one of the following on the manufacturer’s specifications:
- Equivalent Noise Level
- Self-Noise
- Signal-to-Noise Ratio (SNR)
If only SNR is provided, you can estimate equivalent noise using:
Equivalent Noise (dBA) ≈ 94 dBA − SNR (dB)
Example:
SNR = 87 dB
Equivalent Noise ≈ 94 − 87 = 7 dBA
That’s considered an excellent result.
Self-Noise Isn’t Everything
A low self-noise specification is great, but don’t choose a microphone based on that alone.
Also consider:
- Sound character — Bright, warm, smooth, or neutral?
- Sensitivity — Low sensitivity often requires more preamp gain.
- Polar pattern — Cardioid, omnidirectional, or figure-eight?
- Maximum SPL — Important for loud vocals and instruments.
- Physical size — Especially relevant for on-camera content creation.
For example, many classic studio condenser microphones have self-noise between 12–16 dBA, yet they remain favorites in professional recording studios because of their exceptional tone.
Self-noise is a starting point—not the final deciding factor.
Buying Advice
- Identify your recording scenario first. Recording a podcast, ASMR, voice-over, or loud instruments each has different requirements.
- For most voice recording, choose a microphone with self-noise below 15 dBA. If you’re producing ASMR or whisper recordings, aim for below 10 dBA.
- Listen to real recording samples instead of relying only on specifications. Search for microphone demos on YouTube or other review platforms to evaluate their actual sound.
- Don’t overlook your audio interface or preamp. Even a low self-noise microphone can sound noisy if paired with a poor-quality preamp.
- Use proper microphone technique. Good positioning, reasonable recording gain, and a quality shock mount can all help minimize perceived background noise.
If you’re looking for a large-diaphragm condenser microphone with exceptionally low self-noise, consider models that specify below 10 dBA. For example, the TZ Audio Stellar X3 is rated below 8 dBA, making it well suited for whisper recording and other high-gain applications.
That said, no microphone is perfect for every recording situation. Choose based on your budget, recording environment, and intended use.
The key takeaway: Low self-noise provides a cleaner foundation, but great recordings ultimately depend on a combination of room acoustics, microphone placement, performance, and post-production.
FAQ
Q1: What’s the difference between self-noise and environmental noise?
A: Self-noise is the microphone’s own inherent electronic noise and is always present. Environmental noise comes from sources such as air conditioners, traffic, computer fans, or room ambience. Environmental noise can often be reduced through acoustic treatment or better recording conditions, while self-noise can only be improved by using a quieter microphone.
Q2: Is a microphone with 18 dBA self-noise acceptable for podcasting?
A: Yes. You can improve results by:
- Keeping the microphone within 15–20 cm (6–8 inches) of your mouth.
- Using appropriate recording gain.
- Applying gentle noise reduction during editing if necessary.
However, for long-term podcast production, a microphone rated below 15 dBA will generally provide cleaner recordings.
Q3: Do dynamic microphones always have lower self-noise than condenser microphones?
A: Not necessarily. Dynamic microphones have simpler electronics and typically generate very little internal electronic noise. However, because they produce lower output levels, they often require much more preamp gain, making preamp noise more significant. Modern condenser microphones with well-designed electronics can also achieve extremely low self-noise.
Q4: Is an 80 dB SNR microphone considered good?
A: An 80 dB SNR corresponds to approximately 14 dBA equivalent self-noise, which is perfectly suitable for most podcasts, voice-overs, and general recording. For ASMR or other extremely quiet recordings, many professionals prefer microphones with SNR above 85 dB (equivalent noise below approximately 9 dBA).
Q5: I hear a faint hiss while recording my podcast. Is it self-noise or environmental noise?
A: One simple test is to record about 10 seconds of silence with your microphone connected and recording normally.
- If the recording contains a consistent, steady noise floor, you’re likely hearing microphone or preamp self-noise.
- If the noise changes depending on your surroundings, it’s probably environmental noise.
Another easy test is to monitor your audio with headphones and temporarily disconnect or power off the microphone. If the hiss disappears, the microphone or its electronics are likely contributing to the noise. If the hiss remains, the source may be elsewhere in your recording chain or your environment.