Westone W40

Westone Series In-Ear Monitor Earphones with 4-Way Quad Balanced Armature Driver


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The Quad-Driver Westone W40 earphone

The Westone W40 Headphones Offer an Incredible Listening Experience

The Quad-Driver Westone W40 earphone will take your listening experience to an entirely new level. Four balanced armature drivers and a three-way crossover network deliver breathtaking clarity and realism. Westone's True-Fit technology provides superior ergonomics and comfort.

Westone True-Fit Technology

Westone W50 True-Fit Technology

Fifty years experience with in-ear applications has yielded a low-profile, lightweight, universal earpiece with optimum ergonomics and fit. The True-Fit sound port delivers maximum comfort and in-ear coupling for dynamic transfer of sound.

Balanced Armature Drivers

Westone W50 Balanced Armature Drivers

Operating on different functional principles than traditional dynamic, moving coil drivers, balanced armature drivers are significantly more compact and efficient, allowing for a more comfortable, electronically sensitive, and sonically accurate end result.

Acoustic Symmetry

Westone W50 Acoustic Symmetry

The Westone W40 in-ear monitors feature left and right earpiece responses that are matched to an extraordinarily tight +/- 2dB tolerance. These tight responses deliver unparalleled balance and accuracy of sound-stage reproduction giving you the best sound quality possible.


Westone W50 EPIC MICS Cable

For the active user or mobile professional, Westone's MICS (Microphone In Control System) gives simple, one-button control for music playback plus answer/end call, voice control, and communication on most smartphones.

General Features:

  • Wired W Series In-Ear Earbuds
  • 4-way quad balanced armature drivers ( 2 low frequency, 1 mid-range, and 1 high frequency)
    • Each balanced armature driver only weighs 0.66 grams
    • 4 drivers combine with a 3-way crossover network to deliver breathtaking sound clarity and realism
    • Not sure what Balanced Armature Drivers are? Click here to read our Headphone Driver Type knowledge base article
  • Integrated microphone with adjustable volume controls for use with iOS devices
  • Lightweight, universal earpiece design delivers maximum comfort
    • Ensures dynamic transfer of sound
  • Primary Color: Black
  • Manufacturer Part Number: Westone 78504
  • Includes red and blue interchangeable face plates
  • W-Series Designed for: Audiophile Listeners
  • Westone Series Is Available In:
  • Authorized Internet Dealer
  • 2 Year Manufacturer's Warranty

Product Specifications:

  • Frequency Response: 10-18,000 Hz
  • Sensitivity: 118dB
  • Nominal Impedance: 31 Ohms
  • Passive Noise Attenuation: 25dB
  • Cable:
    • Detachable: Yes
    • Cord Length: 50" (1.3m)
  • Plug Size: 3.5mm

Product History:

Westone W40 thumbnail
(newest, current model)
Westone Westone 4 (79297) thumbnail
(previous model, replaced by Westone W40)

Headphone Design

Headphone Type

This is the design of the earpieces on the headphones. Some headphones go inside the ear, while others rest on the outside of the ear. This helps you know exactly what type of headphones you will be receiving.

In-Ear: The ear buds go into the ear. Most often, the right and left ear buds are two separate pieces.

Enclosed-Ear: Usually are found on the larger headphones. They rest on top of the ear and have padding for comfort, as well as enclosing the ear to the speaker. This type of headphone helps to filter out surrounding noise.

On-Ear: This type of headphone involves the speaker sitting gently on the ear without going in the ear or sealing it off.

Headband Type

Headphone type refers to the construction of the headphones.

Around the Ear means that the headphones wrap around the ear to provide a secure fit. This is most often seen in active and sports headphones.

Around the Neck means that the headphones wrap around the neck. This is also seen in active and sports headphones.

Earbuds means that the right and left sides of the headphones are separated and will fit securely into the ear. These are small, compact, and user friendly.

Over the Head headphones mean that the right and left speakers are connected with a support that goes over the head and rests on top. This is the typical headphone type.

Specifically For
Some headphones can use an IR Transmitter in your vehicle, while some can be plugged into your media device and be used on the go or at home.
Headphone Application

This is the application that the headphones are designed for. Each application has unique features that make it perfect for particular uses.

DJ: These headphones are durable, loud, and will often allow for one ear listening.

Gaming Delivers explosive sound and allows you to communicate with others.

Home Hi-Fi: These audiophile headphones are engineered to produce high fidelity and accurate audio.

Home/Office: These headphones are designed to produce rich, brilliant sounds that the artists would appreciate.

Sports: Designed for active use. These headphones are made to stay in (or on) the ear during workouts.

Kids: Feature noise limiting technology so that your little ones don't damage their ears listening to music too loud.

On-the-Go: On-the-go headphones are lightweight and often fold up for easy storage and portability.

Student: Compact and rugged enough to survive life in a backpack; inexpensive enough to not hurt the wallet of a student.

Studio: Reproduce music perfectly without any coloration. Look here for reference quality studio monitoring headphones.

Traveler/Airplane: These headphones are compact, lightweight, and have a portable design.

Home Hi-Fi
Acoustic Principle

The basic design of the headphones. There are 3 different types:

Open: Have ports that allow air through the back of the diaphragms, enabling the headphones to sound like the music is coming from an outside source.

Closed: Completely sealed and have no air passing through the diaphragms. Sounds like you are in a closed off room.

Semi-open: Have slots or ports in the back of the cup and are partially open. This allows for a mixed sound between an open and closed headphone.


General Features

Noise Reduction technology removes unwanted noise from a signal. Background or ambient noise can be removed to produce clearer speech and enhanced hearing. Typically these Active Noise Canceling (ANC) headphones are powered and use batteries to activate the noise canceling technology. Also referred to as Noise Reduction or Noise Cancellation.
Device Controls & Compatibility
Refers to the devices the in-line controls are compatible with.
Apple 3 Button (Volume, Track Up/Down, Play/Pause)
Built-In Microphone
This means that the headphones or earbuds have a built-in microphone. This can be a microphone on the cord, built into the headphone, or even a boom microphone. These mics can be used for music devices like iPods, for Smartphones to make and receive calls, or for gaming purposes.
Headphone Connection
This is how the headphones connect to the audio source.

Corded means that the headphones use a cord to transfer the audio signal.

Bluetooth means that the audio signal is transmitted from your device to the headphones via a Bluetooth connection.

Corded or Bluetooth means that the headphones can be used as corded headphones or as Bluetooth headphones. They have an input in one or both earcups for use as a corded headphone while they also have a built-in battery for use as Bluetooth wireless headphones.

Wireless means that the audio signal is transmitted wirelessly to the headphones.

Volume Adjustment
Volume Adjustment means that the headphone (independent of the source) can adjust the playback volume. Many headphones and ear buds have in-line volume control, which allows adjusting the audible volume from a switch on the headphones cord. Other headphones have a volume knob on the headphone can.
Connector Type
The type of connection the headphones use to connect to receive the audio signal from a music source. Traditional headphones use an analog 3.5mm headphone jack. Newer technology has allowed digital signals to be sent directly to the headphone using an Apple Lightning or USB-C cable.
Jack Size
Refers to whether the headphones use a 3.5mm or 1/4" headphone jack connection.
Jack Angle

The Jack Angle refers to the angle of the input jack on the headphone cable.

Straight Jack: Straight plug with no angle.

Angled Jack: Angled plug, usually a 90 degree angle.

Swivel Jack: A swivel jack is able to swivel between a straight plug and an angled plug.

Angled Jack
Detachable Cable
Refers to whether the cable can detach from the headphones. If a pair of headphones has a detachable cable, the cable can be replaced with a longer cable, one with (or without) a microphone or if you accidentally damage the cable.
Color Shades
Primary color shades of the headphones.
Refers to materials used to build the headphones. Most headphones are built from some combination of plastic and metal to give you a durable pair of headphones.
Ear Cushion/Earbud Material
Refers to the material that the ear cushions/earbuds are made from. Ear cushions and earbuds are available in a variety of materials, ranging from basic rubber eartips to plush leather ear cushions intended for maximum comfort.
Protective Case
Refers to whether a pair of headphones come with a protective case.
Hardshell Case
Water Resistant
This refers to the level of water resistance of the fitness tracker. Some fitness trackers are water resistant and can be used while swimming, while others are only splash proof or should not be used near the water.
Ear Hooks
These headphones feature hooks that wrap around your ears for a secure fit.

Audio Features

Driver Type

The physical design of the driver in the headphones.

Balanced Armature:
A balanced armature driver uses a coil wrapped around an armature which is held in between two magnets until it is stimulated by an electrical current. When stimulated, this armature is magnetized which causes it to rotate one way or the other around a pivot point which moves the diaphragm to create sound. Balanced armature driver headphones are generally earbuds and can have multiple drivers in each earbud.

Dynamic drivers are the most common driver type. They feature a permanent magnet, usually neodymium, a voice coil and a conical diaphragm to drive your music. A dynamic headphone driver looks pretty much identical to any typical home theater speaker.

Electrostatic drivers are made up of an extremely thin membrane, usually a coated PET film, stretched between two metal plates. An electrical signal is applied to the metal plates to create an electrical field which, depending on its polarity, draws the speaker diaphragm toward one of the plates which forces air through the perforations in the diaphragm which generates the sound wave.

Planar Magnetic:
A planar magnetic driver is made up of a large membrane suspended between two sets of oppositely aligned magnets. An electric charge is applied to the membrane to induce movement and produce sound waves.

Balanced Armature
The opposition to electric current, a higher impedance means a higher electrical resistance. This is measured in ohms.
31 ohms
An efficiency or sensitivity rating tells you how effectively a speaker converts power into sound. The higher the number, the more efficient the speaker and the louder it will play with the same input power. An efficient speaker helps you maximize your available power. Most sensitivity ratings measure the speaker's output with 1 watt of input, 1 meter from the speaker. Some speakers' sensitivity is measured with 2.83 volts of input, instead of 1 watt.
Efficiency (1w/1m) is not an accurate indicator of a subwoofer's output capability and should not be used as a comparison to other speakers or subwoofers to determine which one is "louder".
118 dB
Frequency Response
The range of frequencies the speaker will reproduce (lowest frequency to the highest). Bigger is better, meaning the wider the range, the better. The optimal range is 20 - 20,000 Hz (which is the range of human hearing).
10 - 18000 Hz
Audiophile headphones represent some of the finest headphones available. Audiophile headphones produce genuinely outstanding sound quality as well as extraordinary build quality, components and comfort. They are truly the finest headphones available.
Built-in Amplifier
This refers to whether the headphones have an amplifier built-in.

What is in the Box?

Main Product
The main product in the box.
Westone W40 In-Ear Monitors
Accessories included with the headphones
Carrying Case
Cleaning Tool
Replacement Ear Tips
Secondary Cable
Paperwork included with the product.
User manual
Warranty/Registration card

Warranty and Return Policy

Parts Warranty Duration
2 years
Labor Warranty Duration
2 years
Warranty Provider

Summary of Customer Ratings & Reviews

Rating Distribution

5 Star
4 Star
3 Star
2 Star
1 Star

Average Attribution Rating


Oswego, IL

Awesome IEM's

March 11, 2015

First, let me say writing product reviews is not my forte; however, I feel compelled to share my thoughts on my Westone’s W40 In-Ear-Monitors.

After researching the different brands of IEM’s available in the market for several months, via the internet and in stores, I purchased a pair of Westone W40 IEM’s. This was a major purchase; I’ve owned several other brands over the years, but nothing remotely close to this investment price for IEM’s. I travel for work and was looking for IEM’s that had the following qualities:

• Comfortable, with noise isolation qualities
• Clear, controlled sound
• Bass delivered as it was intended (full but not overpowering)
• Compact light travel case

My W40’s arrived and I could not wait to plug them in to see how they sounded. My first impression was they were just OK; not great, but not bad either…just neutral. Factored into my decision was the required time to ‘burn in’ for my W40’s. My W40’s came to life (WOW) after about 50 hours of use. Activities during the ‘burn in’ phase included, listening to music, watching movies and multiple conference calls using the provided MFI cable.

Here are my thoughts after two weeks of using my W40’s – SWEET, AWESOME, FANTASTIC! The sound is absolutely impeccable! I enjoy hearing the bass (robust and full, while not overpowering), the beautiful mids and trebles are balanced along with superb separation of instruments and vocals (in many instances, I feel like I am hearing new instruments in my music selections). I am simply amazed with the clarity and overall sound my W40’s deliver.

Additional items worth mentioning:

• People sound like they are sitting in the same room with me during conference calls when I dial in from a remote location. The pitch is flawless (an added benefit I did not consider in my purchase requirements).
• The product comes with two types of ear buds; silicone and foam in multiple sizes. My recommendation is to try both types of ear buds and the different sizes. It took me about a week of trial and error to find the ones that work best for me.
• The mini vault is a nice touch, but I find it difficult to store my IEM’s with the MFI phone cable attached.

While the price was higher than I planned on spending, I don’t regret my purchase. My W40’s are everything I thought they would be and more. My only regret …not buying them sooner.

38 of 47 found this helpful

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East Selah, WA.

Very good

March 31, 2015

I had never spent this much money on ear buds. I was a little reluctant to shell out that much money but I wanted the great sound that everybody was raving about. I took the plunge and have been very happy with these Westone w40. I use lossless music files and I can listen to them for hours on end. My Ibasso dx50 died just after I received them so I had to go a week before stepping up to the Fiio x5. This is a very good pairing. I get lost in the music now.

33 of 39 found this helpful

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North Cali

W40 Review

July 27, 2016

Preface: I primarily listen to rock and roll, hip hop, and electronic music. During my testing I

enjoy nice clean bass, decent mids, as well as a good open soundstage. I primarily use

earbuds for traveling so another important factor is sound isolation. All testing was done on with

the Lotoo Paw Gold DAP.

Features: Some key features this IEM includes a detachable cord so if you would like to

upgrade your cable you could do so. It also comes with quite a few tip choices including True-

Fit foam tips as well as Star silicone tips of various sizes. This quad driver IEM has an

impedance of 31ohms and comes with red, blue, and black faceplates. The quad driver design

includes four balanced armature drivers with a three way crossover. Also includes a hard travel

carrying case as well as extra cable which includes a three button Apple control system with


Build Quality: I feel the build quality on these is excellent only issue I have is the connector

with the detachable cord. It doesn’t stay in place but however rotates so at times could be

difficult to position correctly.

Comfort: These IEMs have a thin barrel which allows for good fit into the ear canal. When it

comes to IEMs with thinner barrels I usually have to use triple flange ear tips in order to get the

best sound and seal. However, for this IEM I preferred the foam tips as the barrel isn’t long like

in other IEMs such as the Shure SE535.

Bass: The bass on these was nice and clear. The mids don’t get overshadowed by the bass

and the bass hits are very clean. It doesn’t hit as hard as some other IEMs I have tried but I feel

like this is a nice change as it doesn’t take away from the beauty of vocals. It may not reach

down as low as you would like but definitely makes up in other areas.

Mids: Mids are solid and clear. You can clearly hear the instruments as well as the vocals.

This is in part to the excellent implementation of the crossover I feel. With the bass not as

pronounced it allows for excellent mid and treble extension. I would easily highlight this as

being the star of the show. Just an excellent reproduction of music and such a clean sound.

Treble: Treble is very solid on the W40 as it’s not too bright or tizzy. To some it might sound

slightly rolled but I feel there is a certain balance you need in order to achieve good quality

treble. For me too much treble extension could cause fatigue however, cymbal hits are great

and don’t cause fatigue or discomfort.

Soundstage/Separation: The soundstage and instrument separation on the W40 is the

highlight for me. The details come through very clear. It’s what I would call the ideal sound

stage for me as everything comes through very clearly. You don’t miss anything and are able to

catch details that usually aren’t present when the sound stage is too cluttered.

Overall: This IEM is valued at $499.99. I think if you like music and are looking for an IEM with

solid mids and great treble extension this might be the IEM for you. The tonality is excellent and

felt that this IEM overall just really enjoyable. Excellent for vocal focused music like Diana Krall

as well as jazz, classical, and the blues.

Thank you for reading my review and I hope this helps with your purchase decision.

0 of 0 found this helpful

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Browse 1 question and 7 answers
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Why did you choose this?
Sonic Electronix Store
It's on sale.
kelvin N on Nov 28, 2016
The price is cheaper than other sellers.
JIA MING G on Sep 12, 2015
Clarity and instrument separation while staying musical
ANURAG G on Dec 23, 2015
I chose the Westone W 40 because I had read good reviews of the W4, the W4R, and also the W 40. I want to begin to get into portable HiFi audio, and these are my start.
Bernard S on May 8, 2015

Product Summary


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Sonic Electronix Wiring Guide

Wiring Diagram Legend

Warning: The image depicted shows the resistance change when wiring multiple subwoofer terminals. Please refer to your subwoofer's owner's manual for the proper wiring of its terminals. Sonic Electronix, Inc. is not responsible for damage caused to your audio system or vehicle due to improper installation. Please call tech support at 1-877-289-7664 if you require additional assistance.

Product Name: Westone W40

Item Added to Cart

Westone W40

Westone Series In-Ear Monitor Earphones with 4-Way Quad Balanced Armature Driver


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