How To Read Microphone Spec-Sheet?

Making that boring but important stuff easy to understand

Buying a microphone is a bit like buying a car. If you’re not a seasoned gearhead, you probably don’t know everything about the particular technology involved yet you want to be sure beyond reasonable doubt that you are about to invest in something that meets your professional needs perfectly.

In fact, buying a microphone might even mean more responsibility in some cases. It will definitely be so if recording and producing music is how you earn (or plan to) your money.

The important information is usually in the specifications sheet but who has time to decode all of that stuff right?

Well, JZ Microphones engineer team has agreed to share a few pointers so read up and be more informed when buying your first or next microphone!

Transducer type

A Microphone is in itself a transducer. It means that is a device which can convert one form of energy into another.

This information will usually appear at the top of the spec sheet because when the manufacturer is talking about transducer types, he is giving you the information about what sort of technology does this microphone use to convert sound of any given source into an electrical signal and store it for you on, let’s say, a laptop where your DAW is installed, for example. Or on tape if you’re just that fancy (good for you).

The types (as of now) are dynamic, condenser (electrostatic) and ribbon.

A microphone with a dynamic capsule uses diaphragm, magnet and a voice coil. The latter is attached to the diaphragm and surrounded with magnetic field. The motion of the voice coil in the particular environment (caused by you singing, playing guitar or dropping the the mic) generates an electrical signal which “interprets” the sound waves and blasts them through the speakers in concerts or records them, if you’re using a dynamic microphone to track an electric guitar, played through 4x12.

Condenser microphones are famed for their sensitivity to sound and wide frequency range (will get to this later on). Condenser microphones utilize a capacitor that converts acoustic signal into an electrical one. It consists of two plates with metal surface, suspended very close to each other with voltage across them (a capsule). One of the plates acts as a diaphragm and the other is called a back plate.

The diaphragm detects and reacts to subtle changes in the air pressure, caused by sound waves as you speak, sing or play, and the distance between it and the back plate changes. This causes the voltage (the electrical signal) to change and serves as a way to capture the sound.

Ribbon microphone is essentially a dynamic microphone in which a very thin strap of metal (ribbon) is used instead of a moving coil (suspended in intense magnetic field). Ribbon microphones provide the same sensitivity as condenser microphones but they have a very different, distinct character.

The diaphragm size (condenser microphones)

[Note: think of a good “size matters joke” and insert it later on]

If you’re looking for a main studio condenser microphone with which to record vocals and alike, you’ll probably be offered a large diaphragm one.

Generally, any condenser microphone with a diaphragm that is wider in diameter than one inch is considered large. Anything below this will be considered small diaphragm and if that’s the case, you’re probably looking at a pencil microphone. Both have their strengths and weaknesses, depending on situation.

Frequency response

The Hz range provided in the spec sheet should accurately inform you about the lowest and highest frequencies the microphone can capture and record. A 20 HZ to 20 000 Hz pretty much covers everything that can be heard and enjoyed by a human ear.

When considering a purchase of a new microphone, you should also take a look at the frequency graph. It tells you a few things about how this microphone reacts to bass, midrange and treble frequencies and which ones will dominate in the sound it reproduces.

Think of it as that small-print description on your vine bottle, giving you hints about it’s taste. The almost flat line means the microphone has little-to-no coloration and is able to produce very precise, natural recordings.

Maximum SPL

Maximum SPL (sound pressure level) specification informs you about the loudest signal the particular microphone can handle without distorting it to a certain degree. Anything above 120dB should be more than enough if you’re not looking to record an explosion of an old star up close.

When inspecting a particular microphone, it is important to find out the SPL at which something called Total Harmonic Distortion (THD) occurs. To put it simply – it is the slight change in the recorded audio when compared to the sound source.

It will usually be depicted (if it is depicted at all) as THD of 1% or even as low as 05% (less is better) and means that at this particular SPL a very small THD occurs which can be heard.

JZ Microphones BH1s maximum SPL is 134.5 dB SPL (2.5kΩ, 0.5% THD).

Noise level (self-noise) and signal-to-noise ratio

The measure of how loud the microphone itself is. Since microphone is a relatively complex electrical device, used in the particular environment, it is bound to emit sound. However, the less sound it produces, the better.

A noise level of below 20dB-A is very good, anything below 15dB-A is stellar and probably means you are looking at a premium class studio microphone.

Signal-to-noise ratio is another way of expressing how noisy (or quiet) the microphone is. The depicted level of dB tells you exactly how much louder the signal is when compared to self-noise.


The aforementioned technical specifications are what distinguish a good mic from a bad one and that’s a good start to finding out whether it is even worth your time to inspect the product closer.

But the most important thing about buying a microphone is knowing what kind of work will you be doing with it.

If you have decided to invest in a microphone, you should avoid cruising shops and choosing something that caught your attention at a particular moment.

Instead make a list of factors that are of crucial importance: will you use the microphone as an all-round recording tool? Will it be a vocal mic? A guitar mic? Will you only do radio or voiceover? Are you about to record various ambiance for a movie of some sorts?

Sound perception is very subjective therefore it is important to do all you can to match-up the sound in your head for a particular application with the sound that is reproduced by the microphone you’re using.