In order to fulfill the basic functions of our service, the user hereby agrees to allow Xiaomi to collect, process and use personal information which shall include but not be limited to written threads, pictures, comments, replies in the Mi Community, and relevant data types listed in Xiaomi's Private Policy. By selecting "Agree", you agree to Xiaomi's Private Policy and Content Policy .


[Off-Topic] [Device Team] [Tech Class] Chapter 21: All about Speakers

2017-07-15 03:01:38
17444 219
Hi, Mi-Fans

Welcome to  Tech class session. Speaker is the essential thing for the sound output for any device whether it can be taking a call in loud speaker mode or enjoying music/movie.
So in this tech class, we are going to learn about this Speaker thing.

What is a Speaker?

Speaker is an electroacoustic transducer which converts an electrical audio signal into a corresponding sound. Speaker takes an electric signal and converts it back into physical vibrations, which create sound waves. If everything works just like it should, the speaker produces the vibrations close to those in microphone that produced the electric signal.
In short, a loudspeaker is an item that is used to create the sound in radio, TV, Mobile Devices, and any sound output systems.

How does it work?

Mainly a speaker consist of the following parts:

  • Diaphragm (cone): Moves in and out to push air and make a sound.
  • Dust cap (dome): Protects the voice coil from dust and dirt.
  • Surround: A piece of elastic rubber, foam, or textile flexible which fastens the diaphragm to the basket (outer frame).
  • Basket: The sturdy metal framework around which the speaker is built.
  • Spider (suspension): A flexible, corrugated support that holds the voice coil in place, while allowing it to move freely.
  • Magnet: Typically made from ferrite or powerful neodymium.
  • Bottom plate: Made of soft iron.
  • Pole piece: Concentrates the magnetic field produced by the voice coil.
  • Voice coil: The coil that moves the diaphragm back and forth.
  • Former: A cylinder of cardboard or other material onto which the coil is wound.
  • Top plate: Also made of soft iron.
  • Cables: Connect stereo amplifier unit to voice coil.

When there is no electrical current applied to the coil, it's just hold in place by the diaphragm and the spider. When an electrical current is applied the coil becomes an electromagnet, and inside the constant magnetic field of the permanent magnet it moves up or down, depending on the polarity of the applied current. The positive end of electromagnet is attracted to the negative pole of the permanent magnetic field, and its negative end is repelled by negative pole. When the polar orientation of the electromagnet switches, the direction of attraction and repulsion changes too. This moves the coil, which moves the diaphragm and creates physical vibrations causing sound waves to be formed. What the speaker drivers do is constantly changing the polarity of electromagnet.
You can experience it from the below gif

Types of Speakers

The mostly used type of speakers are : Full-range drivers, Subwoofer, Woofer, Midrange driver, Tweeter, Coaxial drivers, Horn loudspeakers.

1. Full Range Drivers: A full-range driver is a speaker designed to be used alone to reproduce an audio channel without the help of other drivers, and therefore must cover the entire audio frequency range. These drivers are small, typically 3 to 8 inches in diameter to permit the reasonable high-frequency response, and carefully designed to give low-distortion output at low frequencies, though with reduced maximum output level.

2.Subwoofer : A subwoofer is a woofer driver used only for the lowest-pitched part of the audio spectrum: typically below 200 Hz for consumer systems, below 100 Hz for professional live sound, and below 80 Hz in THX-approved systems. Because of propagation delay, their output may be somewhat out of phase from another subwoofer (on another channel) or slightly out of phase with the rest of the sound. Consequently, a subwoofer's power amp often has a phase-delay adjustment which may improve performance of the system as a whole at subwoofer frequencies

3.Woofer : Woofer is a driver that also reproduces low frequencies. The driver works with the characteristics of the enclosure to produce suitable low frequencies

4. Midrange driver: A mid-range speaker is a loudspeaker driver that reproduces a band of frequencies generally between 1–6 kHz, otherwise known as the 'mid' frequencies -between the woofer and tweeter.

5.Tweeter: A tweeter is a high-frequency driver that reproduces the highest frequencies in a speaker system

6.Coaxial Drivers: Coaxial driver is a loudspeaker driver with two or several combined concentric drivers.

7.Horn Loudspeaker: Horn loudspeaker is a loudspeaker or loudspeaker element which uses an acoustic horn to increase the overall efficiency of the driving element.

8. Smartphone Speakers/Device Speakers: Mobile speakers are very small to be fit into a thin casing and even in a small sized device also. This speakers can play very loud, but the sound quality in mobile speakers can never be the same as in standard size speakers. Smaller speakers are more suitable for playing high-frequency sounds. So it's just your feeling that they are loud - because of the amount of high-frequency sounds coming out from them.

Speakers can be of different sizes and shape to suite your need. But it need to be more durable to take all kind of sounds.Nowadays mobile manufacturers  are building the speakers of a higher  quality and also to better fit the devices. Xiaomi is now using MEMS speakers in its smartphones. This allows them to minimize the thickness of the final devices, but produces a significantly better sound quality than standard small-sized electrodynamic speakers do.

Credits: Google, Wikipedia, & other blogs.
Special Thanks to @ansarifauwaz @paramgagan and fellow DT members

Chapter 16: All About TWRP
Chapter 17: All About RAM
Chapter 20: All About Batteries
Was this thread helpful to you?
Single Poll thread Total 152 Users Voted
96.71% (147)
3.29% (5)


Number of participants 10 Experience +73 Pack Reason

View Rating Log

2017-07-15 03:01:38
Favorites136 RateRate
nice..thanks g\for so informative thread
2017-07-23 03:43:16

Rookie Bunny

1670826341 | from app


which is better redmi 4 or redmi note 4
2017-07-23 03:57:57

Master Bunny

Shreyasrocks97 | from mobile


Thank you for sharing
2017-07-23 04:03:20
thanks for this great information bro.
2017-07-23 05:39:56

Rookie Bunny

1713644638 | from Redmi 4A


note 4 is better
2017-07-23 15:03:06

Rookie Bunny

1702229280 | from Redmi 4A


My redmi 4A is working in only hands free mode!  Normal mode is not working
2017-07-23 22:33:09

Master Bunny

Aman35442 | from Redmi 3S


thanks for sharing
2017-07-24 01:04:15
Amandeep Singh

Master Bunny

ramankad | from Redmi Note 4


good described
2017-07-24 01:12:07
Raman kr
Thank you mi for speakers information .
2017-07-24 01:15:27

Semi Pro Bunny

Vicky Rattan | from Redmi Note 4


Such a great information provided by you.  Thank you
2017-07-24 01:17:41
please sign in to reply.
Sign In Sign Up



  • Followers


  • Threads


  • Replies


  • Points


India 2nd year
100K members
Redmi 3S
3 Days Check-In
7 Days Check-In
21 Days Check-In
40 Days Check-In
70 Days Check-In
100 Days Check-In
Lucky Draw No.
Mi Explorers
1 million members
June-100 replies in a month
July-100 replies in a month
Aug-100 replies in a month
Oct-100 replies in a month
Dec-100 replies in a month
100 ответов в декабре
1st Anniversary
71st Independence Day
My Poster My Life
2 million registered members
Newbie Member
Device Team Member
2018 New Year Medal
2017 Xiaomi Annual Bill
Mi Community Updater
MIUI 8th Anniversary
Go Bunny Master
Mi Music: 20 FREE Downloads
Ringtones Mania
Throwback With Mi 2018
Dark Mode
#AnswerMi Vol 1
Holi Hai!

Read moreGet new
Copyright©2010-2020, All Rights Reserved
Content Policy
Quick Reply To Top Return to the list