BestCarAudio.com

Showcasing the Best in the Mobile Enhancement Industry

Showcasing the Best in the Mobile Enhancement Industry
  • Upgrades
    • Marine Audio
    • Motorcycle Audio
  • Articles
    • Bluetooth
    • Car Audio
    • Motorcycle Audio
    • Navigation
    • Remote Starter
    • Satellite Radio
    • Smartphone Integration
    • Test Drive Product Reviews
    • Vehicle Insights
  • Profiles
    • Installation Profiles
    • Installer Profiles
    • Retailer Profiles
    • Vendor Profiles
  • Products
  • Dealer Locator
  • Shop
  • Facebook
  • Twitter
  • Instagram
  • 0 items
Home » Car Audio » What Is Signal-To-Noise Ratio, And Why Does It Matter?

What Is Signal-To-Noise Ratio, And Why Does It Matter?

October 19, 2016 By 1sixty8 media 1 Comment

Signal-To-Noise RatioMost people understand the importance of amplifier power specifications. In most cases, more power is a good thing, that is, until you reach the thermal or suspension limits of the speakers you are using. One specification that is also very important in a mobile electronics amplifier, processor or source unit is Signal-to-Noise Ratio. In this article, we are going to explain what S/N Ratio numbers are and why they are important.

All the Noise, all the Time!

Signal-To-Noise RatioIt just so happens that when you pass a signal through any device – like a piece of wire, resistor, capacitor, inductor, transistor or anything else you can think of – a tiny little bit of noise is added to the signal. There are many different kinds of noise. The random motion of electrons bouncing around as they pass through a device causes thermal noise. Higher temperatures result in more noise. Another common noise is Shot Noise. The difference in arrival times of electrons as they cross a barrier or gap between two materials causes Shot Noise. Devices like transistors and diodes, which have different layers of materials inside, are common sources of Shot Noise. There are many more types of noise.

As you can imagine, the amount of noise generated by any one of these devices is minuscule. When you add up a little bit of noise from a bunch of components, then you amplify the resulting signal, the amount of noise in the output of a circuit grows dramatically.

Noise happens in source units, signal processors and amplifiers. Once you add noise to the signal chain, it’s essentially impossible to remove it.

The Sound of Noise

Signal-To-Noise RatioAn easy way to hear what noise sounds like is to connect a set of headphones to your laptop computer and turn the volume up fairly high. You’ll hear a hiss through the headphones. That’s noise. (Note: Please be careful, we want you as an audio enthusiast for life. Take those headphones off before your computer plays a sound and you risk damaging your hearing.)

How We Measure Noise

Signal-To-Noise RatioThere are a few ways to quantify the noise an electronic component creates. One method is to simply state the noise on the output of the device in absolute terms. The measurement could be in volts or watts, and quantifies the amplitude of the noise signal. You won’t see this used to describe audio components, however.

The most common method of quantifying the noise that a product adds to the signal is to compare the noise level to that of the audio signal coming out of the device. Because the difference in these levels can be quite large, we state the ratio of the signal level to the noise level using the decibel (dB) scale. The decibel scale is logarithmic. As such, a difference of 6 dB represents a doubling of the amplitude ratio, 20 dB is ten times the amplitude, 40 dB is 100 times, 60 dB is 1000 times and 80 dB is 10,000 times and so on.

Let us look at a moderate quality amplifier – nothing awesome, nothing disastrous. We see that this fictional amplifier has a S/N Ratio of -82.3 dB when referenced to 1 watt of power output into a 4-ohm load. What does that mean? Well, first, we know that to produce 1 watt of power into a 4-ohm speaker, we need 2 volts RMS of signal coming out of the amp. Our noise level is 82.3 dB quieter than 2 volts. Using an online calculator, that means that the noise produced by this amp is 0.00006918309709189363 times smaller than 2 volts, so it’s about 0.000138 volts. A little more math and that works out to 4.785 nanowatts.

Nope. That isn’t very much noise. And in most cases, you probably can’t hear it.

What if we work hard and find a below-average amplifier? Something with a S/N spec down around 70 dB? If we apply that math to our 2 volts of rated output, we get a noise level of 99.99 nanowatts. Yep, that’s a LOT more watts as compared to the previous example.

Clarifying the Mysterious Signal-To-Noise Ratio

If you look at an amp spec from more than about 10 years ago, or you see a number that is abnormally high, they may be rating the noise level using the maximum output capability of the amplifier as the comparing factor. If we measure an amplifier’s noise output level at 1 watt to be 85 dB, then you increase the amplifier’s output to 10 watts, assuming it doesn’t make any additional noise, the S/N ratio will be -95 dB. If the amp can produce 100 watts with no more noise, the ratio is now -105 dB. There are hundreds of amps that can produce 1000 watts – so that noise ratio measurement would now be -115 dB. When it comes to printing numbers on a gift box, in a brochure or publishing them on a website, being able to say that the S/N Ratio is -115 dB sure looks more appealing than -85 dB.

Signal-To-Noise RatioThe CEA-2006 specification established a standard set of guidelines for S/N Ratio noise measurement. The specification dictates that we measure the S/N Ratio compared to 1 watt of output into a 4-ohm load. A new specification is in the works that will help quantify the adjustment of the sensitivity setting on the amplifier during the measurement process. As it sits, the lower the setting of the amp, the better the S/N ratio measurement will be. Want to confirm this? Next time you are installing an amp, turn the system on with no signal connected to the amp and listen to the speakers. Then turn the amp gain up all the way. You will hear the noise level increase. Please turn the gain back down and shut the system off before proceeding.

Why is the Lack of Noise Important?

How can we quantify the desire not to add noise to our signal? Here is a simple analogy. If you purchased a TV in recent years, you may have heard the expression ‘blacker blacks.’ ‘Blacker blacks’ refers to how dark the screen gets when there is no signal. Blacker is better. When you think about your audio system, a ‘more negative’ S/N ratio means that the noise is quieter than the audio signal. We don’t want to listen to noise. -90 dB is better than -80 dB. Got it? Clear?

There are so many criteria to balance when choosing any car audio product. Power levels, efficiencies, distortion characteristics, features and functions all play an important role. Understanding the meaning of the S/N ratio measurement is very important. We don’t want ANY distortion or noise added to our music, but the laws of physics deny us that luxury. Do your best to choose products that, through careful design and choice of internal components, minimize these negative effects. Your local mobile electronics specialist can help steer you towards some amazing equipment. Drop in and check out what’s new.

Share this:

  • Tweet
  • Email

Related

Filed Under: ARTICLES, Car Audio, Resource Library Tagged With: Amplifiers, Processors, Speakers, Subwoofers

About 1sixty8 media

1sixty8 media is a content marketing, website development, and business solutions provider specializing in the mobile enhancement industry. The 1sixty8 media team includes many household names in the industry, from store owners and industry writers to award-winning installers and fabricators. To learn more about 1sixty8 media, visit www.1sixty8.com.

Comments

  1. Agen Sendal Cowok says

    July 24, 2019 at 3:50 am

    Now I am going away to do my breakfast, after having my breakfast coming again to read further news.

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Kicker ad
Audison Forza

Save Time and Money!

Our buying guides will help you make educated decisions when upgrading your vehicle. Click the image above to shop our affordable and informative buying guides.

Industry Profiles

Amp Rack

Pinnacle Autosound Audi Q3 Amp Rack and Subs

August 16, 2023 By Dave MacKinnon 

A short while back, we looked at the stunning Audi Q3 demo vehicle built by Pinnacle Autosound in Lake City, Florida. We … [Read More...]

Dodge Challenger

Mobile Enhancement Industry Profile: 2019 Dodge Challenger

July 28, 2023 By Dave MacKinnon 

Brian Mitchell’s name should be familiar if you’ve looked at results of any significant sound quality auto sound … [Read More...]

Press Releases

Sony XAV-9000ES
Sony Electronics Introduces New Mobile ES Car AV Receiver and Power Amplifiers
RDVFL Mighty Mount Press Release
RDV Becomes Exclusive US Distributor for Mighty Mount
New Heise Connect App Goes Live for Smart Devices
RDVFL CarPlay CP1
RDV Releases New CarPlay Hardware Platform
Maserati Radio
RDV Launches Tesla Style Radio for Maserati

Vehicle Insights

2023 BMW X1

2023 BMW X1. Modern Tech Basics.

Ford Raptor R

2023 Ford Raptor R. Trail Beast and Street Beast

Find Facility Near You

Subscribe to BestCarAudio via Email

Enter your email address to subscribe to BestCarAudio.com and receive notifications of new posts by email.

Popular Categories

  • Car Audio
  • Window Tint
  • Remote Car Starters
  • Vehicle Insights
  • Radar Detectors

Supporting Manufacturers

  • Arc Audio
  • Compustar
  • Hertz
  • Momento
  • Rockford Fosgate
  • Sony

Contact

  • Editorial
  • General
  • Advertise
  • Dealer Locator Guidelines

Miscellaneous

  • Profile Request
  • Press Release Guidelines

Sign up for our newsletter today. Opt out at any time with 1 click.

  • This field is for validation purposes and should be left unchanged.

BestCarAudio.com is a product of 1sixty8 media, inc. · Copyright © 2023 1sixty8 media, inc. · Privacy Policy · Website by 1sixty8 media, inc. · Log in

 

Loading Comments...
 

    x
    x