Mono Vs Stereo Sound – The Difference And Why It Matters

In this article, I’ll compare and explain the differences between stereo vs mono sound, why it matters, and much more.

I’ll also show you how stereo and mono sound connectors are different. Read on to learn more!

Mono vs stereo sound differences explained

stereo vs mono sound comparison diagram

Stereo vs mono sound explained

  • Mono sound uses only one audio signal channel to carry the musical content. The sound you hear is the same whether one or more than one speaker is used.
  • Stereo audio uses two separate audio channels to carry a stereo recording with musical signals can differ between the two. With a stereo speaker system, 2 channels can reproduce the original recorded left to right placement of musicians and instruments as intended in the recording studio.

While a mono microphone is fine for mono audio or studio recordings, a stereo microphone is rqeuired at the minimum for true stereo. However a mono track can also be created using two or more studio audio signals mixed into one.

Why was mono popular for decades and still today?

old radio mono sound examples

In the olden days technology was very limited, meaning once it was possible to record and reproduce sound the storage capacity was limited. Mono sound also was used for decades due to the origin of broadcast radio and portable radios that later came to be once the transistor became widely available.

In the days of fireside chat presidential address, news, singers or musical groups, or spoken word entertainment, stereo wasn’t necessary. While the original home radio receivers used simple tuners and vacuum tube circuits they were a remarkable step forward in entertainment for many people before the time of the television.

Home portable and pocket radios weren’t as inexpensive as today, meaning the mono design kept costs down. Likewise, monaural sound designs are simpler and help keep the amount of wiring and complexity down.

Stereo vs mono system AM and FM radio

Amplitude modulated (AM) mono radio was the original radio station broadcast technology. As radio broadcasts and consumer tastes changed over the years, it was typically used for talk radio and news content which doesn’t need stereophonic sound.

Frequency modulated (FM) radio was later introduced, offering better sound quality and the ability to transmit stereo music added during the transmission (modulation) process. FM mixes two separate audio channels into one broadcast signal using a carrier frequency and modulation process.

Likewise, the two channels are demodulated (extracted) on stereo-capable radios which then provide a left and a right output.

It’s also backward compatible with older (mono speaker) radio technology. FM radio uses up more bandwidth (space on radio frequency spectrum) than AM radio, however.

Music media

vintage mono record album example

Musical recordings (such as vinyl records) were originally sold as a mono record version until stereo pressing machines and stereo record player designs came to market. In fact, many popular albums had a stereo version promoted as better sounding than the mono version.

Stereo vs mono audio cables and connectors

Stereo vs mono audio plug comparison diagram

stereo vs mono plug pinout comparison diagram

Mono sound is very simple in that it normally only requires two conductors:

  1. The signal conductor (positive wire, or “+” marked wire.
  2. A ground conductor wire.

Stereo sound is similar but adds a 2nd signal conductor wire. For analog (non-digital) cables, one is marked for the left channel and one for the right. These are very often represented by white for the left and red for the right, although this practice isn’t always followed.

Headphone plug connectors (3.5mm, 1/8″), 1/4″, and RCA style cables are some of the most popular. Tip-ring-sleeve (TRS) styles such as headphone plugs use a tip (T), one or more rings (R), and one sleeve (S) conductor that make contact with points in a matching jack.

TRS and RCA plugins are used in a wide variety of audio systems:

  • Portable audio (headphones, music players, etc.).
  • Car stereo system installations (stereo RCA cables are used here).
  • Home stereo system receivers, amplifiers, and home theater systems (RCAs).
  • Public address (PA) type audio system in music venues, churches, theaters, and auditoriums. 1/4″ or XLR type connectors are common here.
  • Studio or amateur music recording.

RCA connectors use a center pin that carries the musical signal for that channel and a second conductor (sometimes called the shield) as the negative (-) conductor.

Additionally, some 3.5mm jacks and connectors may add a 4th ring conductor for optional microphone use. This usually requires an adapter when using the musical conductors at the same time.

What does it mean when a song is mono or stereo?

diagram showing how stereo imaging in music works

  • A mono musical track uses a single sound channel even if multiple microphones or mix tracks were used in the studio. A mono song has all independent sounds sources mixed into one track.
  • A stereo song contains information for two separate channels (left and right) that can reproduce the placement of the stereo microphones, vocals, and instruments as recorded in the studio.

A stereo song, when used on a good quality speaker system with 2 speakers, can recreate stereo imaging. Imaging is the representation of stereo field spatial cues your ears hear and that your brain interprets to be able to tell where sounds are coming from. This comes both from stereo reverb the microphones pick up as well as the different sound levels between the left and right.

For example, many stereo songs have the singer’s vocals placed in the center and not only the left or right. Other instruments will appear to come from the left, the right, or in between according to what you hear.

Stereo track recordings can also be “downmixed” (combined) into mono tracks. This avoids missing out on some portions of the music which happens when playing on one channel.

Which is better – stereo or mono?

The truth is that there’s not a single best answer – it depends on the application.

  • For music and movies, in most cases a stereo effect provides a much more enjoyable listening experience.
  • Mono is great for vocal media content like news, podcasts, and more.
  • Mono is ideal for sound system installation where there’s usually a single speaker, presenter, or another sound source.
  • Stereo is ideal for concerts or other recordings you’d like to save with a high-quality recording. You can always play stereo tracks you’ve saved as mono but the reverse isn’t true.
  • Mono is great for cases where you’re using a single earpiece or mono headset for communications or other listening purposes.

Can you get surround sound from mono or stereo?

Dolby Pro Logic stereo surround sound decoder diagram

You can get some types of surround sound from a stereo signals source but not from a mono signal.

Dolby Laboratories introduced the original Dolby Pro Logic surround sound format in the early 1980s for use movie theater speaker systems. The Dolby Pro Logic (the most recent version being Pro Logic II) format became available to consumer products in 1987.

While you cannot get a 5.1 surround sound effect like with DTS or Dolby Digital formats, Pro Logic can decode a 2.1 surround audio effect into 2 analog (non-digital) channels which can be carried by nearly any standard stereo recording.

You’ll need a surround sound decoder to do so.

Pro Logic uses a matrix and additional functions to decode the Pro Logic II stereo signal into:

  • Front left and right channels
  • A center channel (optional)
  • Dual mono surround sound speaker outputs with a slight time delay (these are derived from the stereo channels and altered so as to mimic a surround effect)

Other formats and gimmicks have existed to produce a “surround” effect from standard non-Pro Logic recordings but they’re nearly always mediocre at best. Some video games use a 2-channel audio track to provide Pro Logic II output as an option.


About the author

Marty is an experienced electrical, electronics, and embedded firmware design engineer passionate about audio and DIY. He worked professionally as an MECP-certified mobile installer for years before moving into the engineering field. Read more »

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