Guide to Subwoofers: Setup Tips, Crossovers, and more

Written By: 
Robert Silva
Tags: 
Share:
  •  

Ecoustics’ Robert Silva dives into the basics of subwoofers and what you need to know.

In order to experience great sound in a speaker setup, you need speaker drivers that provide clarity, depth, and the ability to provide a full range of audio frequencies. Tweeters are designed to handle high frequencies, the Midrange driver handles the frequencies associated with vocals, while a Woofer handles the low frequencies. This is referred to as a three-way speaker.

Many times, especially for compact speakers, the midrange and woofer are combined into a single speaker (aka a 2-way speaker). More on 2-way vs 3-way speakers.

What a Subwoofer Is

REL HT/1205 MKII and HT/1003 MKII Subwoofers
REL HT/1205 MKII and HT/1003 MKII Subwoofers

For movies and bass-heavy music, a woofer may not be able to reproduce all of the low frequencies. To provide more sonic impact (hearing and feeling), you need a subwoofer which is a specific type of speaker that handles only the lowest frequencies that other speakers can’t reproduce.

In what is considered a basic surround sound system (5.1 channels), there are five main speakers: Left, Center, Right, Left Surround, and Right Surround. In addition, a  subwoofer is assigned to reproduce low frequencies (usually below 120Hz). The subwoofer is associated with the .1 channel. 

Tip: The role of the subwoofer is the same regardless of how many channels and speakers are in the rest of your system. 

Subwoofer Types

Passive

A passive subwoofer needs to be powered by an external amplifier. The external amplifier may be part of an amplifier that powers the rest of the speakers or more typically, an external subwoofer amplifier that is placed between a preamp or home theater receiver (via a subwoofer output) and the speaker terminals of a passive subwoofer. 

Monoprice Monolith M-IWSUB82 In-Wall Subwoofer Front and Rear
Monoprice Monolith M-IWSUB82 In-Wall Subwoofer
Monoprice Monolith SWA-400 Subwoofer Amplifier Front and Rear
Monoprice Monolith SWA-400 Subwoofer Amplifier

Powered

Powered subwoofers incorporate both the subwoofer speaker driver and an amplifier inside the same enclosure. For the powered subwoofer to work, in addition to AC power, a line output (sub out or LFE out) from a home theater receiver needs to connect to the subwoofer. 

A powered subwoofer takes excessive power load away from the amp/receiver so that the amp/receiver can power the other speakers in a system more efficiently, Most subwoofers used in home theater setups are powered.

In addition to how power and audio signals get to a subwoofer, there are other features that the subwoofer has that contribute to its bass role.

Monoprice Monolith 13-inch THX Ultra Subwoofer Front Back
Monoprice Monolith 13-inch Subwoofer

How Subwoofer Speaker Drivers Are Mounted

  • Front-firing subwoofer is one where the speaker driver is mounted so the bass sound emanates from the front of the subwoofer enclosure.
  • A Down-firing subwoofer is one where the speaker driver is mounted facing down so that the sound emanates from out of the bottom of the subwoofer toward the floor.  
  • Side-firing subwoofer is one where the speaker driver (or two drivers) are mounted on each side of the subwoofer so that the bass sound emanates from one or both sides. 

Subwoofer Enclosure Options

Sealed Cabinet: Some subwoofer speaker drivers are enclosed in a sealed enclosure. This means that all of the air is pushed out directly from the speaker driver into the room. 

Passive Radiator: Some subwoofer enclosures incorporate a passive radiator in addition to the speaker. This increases efficiency and preciseness. Passive radiators can either be speakers with the voice coil removed or a flat diaphragm.

Port: Some subwoofer enclosures offer an additional port. This forces out more air, as it is coming from both the speaker and the port. Some ports may be cylindrical while others might be slotted. This increases bass response in a more efficient manner than sealed enclosures, but may not be as precise. A ported design is referred to as bass reflex

Wilson Audio Loke Subwoofer Colors Grills On Colors
Wilson Audio Loke Subwoofers

Crossover

A crossover is a circuit that sends frequencies below a specific point to the subwoofer and frequencies above that specific point to the other speakers in the system. 80Hz to 100Hz are commonly used points, but most subwoofers provide additional adjustable crossover points. In addition, most home theater receivers include bass management, which allows further control of what frequencies are sent to the subwoofer. 

Anthem AV MRX Series Bass Management Settings

Sound Dispersion

Deep-bass frequencies (below 80Hz) are non-directional. This means that human ears have difficulty pinpointing the source location of bass frequencies. This means a subwoofer can be placed in a room where its bass response is best in relation to the size of a room, type of floor (carpet, wood, other), furniture placement, and wall surfaces.

Subwoofer Connection Options

REL HT/1205 MKII rear panel
REL HT/1205 MKII Subwoofer Rear

Depending on the subwoofer, the following connection options may be provided. 

  • A Passive Subwoofer features high-level inputs (traditional speaker connections). 
  • Most Powered subwoofers feature low-level inputs (RCA or choice of RCA and XLR Balanced). 
  • Some Powered Subwoofers feature both low-level and high-level inputs. 
  • Some Powered subwoofers incorporate wireless connectivity in combination with, or in place of low-level inputs.

Tip: Most powered subwoofers with wired-only connectivity can also be made wireless via an adapter kit that includes a transmitter that plugs into a subwoofer output of a home theater receiver and a receiver that plugs into the subwoofer inputs.  

SVS SoundPath Tri-band Wireless Audio Adapters Transmitter and Receiver
The SVS SoundPath Tri-Band Transmitter and Receiver

Basic Subwoofer Setup Tips

The most common spot to place a subwoofer is in front of a room, to the left or right main speakers. However, they can also be placed along a wall or in the back of the room. The key is to place it where it sounds best. You want to minimize the “boomy” base as much as possible. The bass should be deep and tight.

Denon Home Subwoofer
Denon Home Subwoofer

Use crossover settings to get the best balance between what the subwoofer reproduces in relation to the speakers in the rest of the system. Most subwoofers provide crossover settings. In addition, most home theater or AV receivers provide crossover (aka bass management) settings that can further tweak what frequencies are sent to both the main speakers and subwoofer. Read your home theater receiver’s user guide for specific details, but here are some possible options:

If you set the main speakers to “large” and have a subwoofer, low frequencies (LFE and non-LFE) will be sent to both the main speakers and subwoofer.

Tip: Depending on the receiver, when set to large the low frequencies may be sent to the front left/right speakers and subwoofer but not to the center or surround speakers.  

If you set the main speakers to “small” all low frequencies, whether they contain a dedicated LFE signal or not will be sent to the subwoofer. 

If your receiver has an LFE+Main setting option all low frequencies will be sent to the Subwoofer (LFE and non-LFE) whether the speaker channels are set to “large” or “small”.

For details on LFE, read our companion article: WTF is LFE?

Subwoofers and Stereo

In addition to home theater and surround sound, subwoofers can also be used in a stereo system for music listening. When a subwoofer is added to a stereo setup, it is referred to as a 2.1-channel setup. 

Klipsch Synergy Black Label 2.1 Speaker System
Klipsch Synergy Black B200 2.1 Speaker System

This can be done in two ways:

1. Some stereo receivers have subwoofer outputs. This means you can connect a powered subwoofer to your system using a single audio cable. 

2. If you have a powered subwoofer that has standard speaker input/output terminals in addition to a subwoofer input, you can connect the left and right channel speaker outputs of your stereo receiver to the subwoofer and route the speaker output connections to your left and right channel speakers. 

This creates a little more wire clutter, but the benefit is that you get an extra bass boost from the subwoofer, which comes in handy if you are using compact-size left and right-channel speakers. 

In this type of setup, you would use the crossover controls on the subwoofer to determine the point where audio frequencies are reproduced by the subwoofer and which frequencies are sent further to the left and right channel speakers. 

Subwoofers and Soundbars

Most soundbars come packaged with a subwoofer, which typically connects to the soundbar wirelessly via bluetooth or Wi-Fi. In this type of setup, the soundbar has a pre-determined crossover point that determines which frequencies are reproduced by the soundbar and which are assigned to the subwoofer. 

2023 Vizio M-Series Elevate M512E-K6 Soundbar System

This article originally appeared at ecoustics.com and has been published here with permission.


In Sheep’s Clothing is powered by its patrons. Become a supporter today and get access to exclusive playlists, events, merch, and vinyl via our Patreon page. Thank you for your continued support. 

Related Articles

Sort By
12th Isle
2020
33rpm
45rpm
4AD
5 Selects
7"
99 Records
A&M
Abbey Lincoln
Aboriginal
Abstract
Ace Tone
Acid
Acid Archives
Acid Folk
Acid House
Acid Punk
Acid rock
Acoustic
Adrian Sherwood
Africa
African
Afro
Afro-Cuban
Afrobeat
Alan Ginsberg
Alan Greenberg
Alan Thicke
Albert Ayler
Alice Coltrane
All Genre
Altec
Amazon Music
Ambient
Amoeba Music
Amplifier
Analog
Anatolian Rock
Andy Warhol
Animation
AOR
Aquarium Drunkard
Archie Shepp
Archival
Art
Art & Design
Art Dudley
Art Film
Art Pop
Art Rock
Artform Radio
Arthur Russell
Article
Ash Ra Temple
Audiogon
Audiophile
Audiovisual
avant
Avant-Garde
Avant-pop
Avant-Rock
Avent-Garde
Balearic
Bali
Ballad
Bargain Bin
Baroque
Baroque Pop
Basquiat
Bass
Bauhaus
Bayou Funk
BBC
BBC Radiophonic
Beats
Beats in Space
Bebop
Belgium
Bennie Maupin
Berlin-school
Best of 2020
Beverly Glenn​-​Copeland
Bhutan Stamps
Big Band
Bill Laswell
Black Ark Studios
Black Jazz
Blaxsploitation
Blue Note
Blues
Blues Rock
Bob Marley
Bola Sete
Bollywood
Boogie
books
Boredoms
Bossa
Bossa Nova
Brazil
Brazilian Folk
Breakbeat
Breezy
Brian Eno
Bruce Weber
Bruton Music
Buddhism
Budget Audiophiler
Cabaret
Calypso
CAN
Canterbury
Cape Verde
Caribbean
Cartridges
Casio
Cassette
Cats
CD
Chamber Music
Channel One Studios
Chanson
Charles Lloyd
Charles Mingus
Chee Shimizu
Chet Baker
Chicago
Chillout
Choral
Christmas
City Pop
Classic Album Sundays
Classical
Classics
Clothing
Coctueau Twins
Coffee
Commercial
Community
Compass Point
Compilation
Concept Album
Condesa Electronics
Conny Plank
Contemporary Jazz
Cornelius
Cosmic
Cosmic Disco
Cosmic Folk
Country
Country-Rock
Covers
Cult Classic
Cumbia
Daft Punk
Dance
Dancehall
Dark
Dark Entries
David Bowie
David Byrne
Davida
Deep Dive
Deep House
Deep Listening
Delia Derbyshire
Demo
Dennis Bovell
Denon
Detroit
Devotional
Diasporic Disco
Dick Verdult
Diggin in the Mags
Disco
Discogs
DIY
DIY / Amateur
DJ
Documentary
Don Buchla
Don Cherry
Donald Byrd
Doom Metal
Downtempo
Dowtempo
Dr. John
Dream House
Dream Pop
Dreamy
Drone
Drum Break
Drum Machine
Drum n Bass
Drums
Dual
Dub
Dub Poetry
dublab
Dubwise
Durutti Column
Düsseldorf School
Eames
Earl King
Early Electronic
East African
Easy Listening
EBM
ECM
ecoustic
ecoustics
Electric Lady
Electro
Electronic
Electronica
Elegant Pop
Emahoy Tsegué-Maryam
Enossified
Environmental Music
EOY
Eric Dolphy
ESG
Esoteric
ESP Institute
Essential Listen
Essential Listening
Essential Listenning
Ethereal
Ethiopian Jazz
Ethnic
Event
Events
Exotica
Experimental
Factory Records
Fela Kuti
Festival
Field recording
Films
Fingertracks
Fingetracks
Fishing with John
Fleetwood Sound Company
Floating
Floating Points
Folk
Folk-Rock
Fonts
Fourth World
France
Free Improvisation
Free Jazz
Friends of ISC
Frippertronics
Fundraiser
Funk
Fusion
G.S. Schray
Gal Costa
Gamelan
Garage Rock
Garrard
Gems from the Dollar Bin
George Martin
Gifts
Gilberto Gil
Glam Rock
Gogo
Gospel
Grado
Graphic Novel
Grateful Dead
Group Sounds
Guide
Guitar
Hard Bop
Harold Budd
Harp
Harry Nilsson
Haruomi Hosono
Heavy Metal
Henry Lewy
Herbie Hancock
hi-fi
hi-NRG
Hidden Gem
Highlife
Hip Hop
Hiroshi Yoshimura
history
Holger Czukay
Holiday
Hollywood
Holy Grail
Home Listening
House
Hypnotic
Iasos
Ibiza
IDM
Illustration
Improvisation
Impulse!
In Conversation
In Stock
India
Indian
Indian Classical
Indie
Indie Rock
Industrial
Ingmar Bergman
Installation
Instrumental
International
Interview
ISC Classic
ISC Collection
isc guide
ISC Record Store
ISC Selects
Island Records
Isolation
Italo Disco
Italy
Jackie McLean
Jamaica
James Baldwin
Japan
Japananese
Japanese
Jazz
jazz kissa
Jazz-funk
Jazz-rock
JBL
John Fahey
John Martyn
Jon Hassell
Joni Mitchell
Judee Sill
Jungle
K. Leimer
Kankyo Ongaku
Keith Haring
Keith Jarrett
Kid-Friendly
Kitty Records
Klaus Schulze
Klipsch
Kompakt
Kosmiche
Kosmische
KPM
Kraftwerk
Krautrock
L.Shankar
La Monte Young
Labels We Love
Lafawndah
Lagniappe Sessions
Laraaji
Larry Levan
Last Resort
Laswell
Latin
Latin Jazz
Laurel Canyon
Laurie Spiegel
Leaving Records
Lebanese
Lee Scratch Perry
Left-field
Leftfield
Lena Horne
Les Baxter
Lester Bowie
Library
Library Music
Liquid Liquid
Listening bar
Live Performance
Live Recording
Los Angeles
Lost & Sound
lost and sound
Louisiana Blues
Lounge
Lounge Lizards
Love Songs
Lovefingers
Lovely Music Ltd.
Lovers Rock
Luaka Bop
Mad Professor
Marantz
Marcel Duchamp
Marcos Valle
mbaqanga
McIntosh
Meditation
Meditative
Melancholic
Mellow
Melody As Truth
Meredith Monk
Metal
Michael Franks
Mid-Century
Miles Davis
Milford Graves
Mills College
Minako Yoshida
Minimal
Minneapolis Sound
Mixes
Mixtape
Mizell Brothers
Mobile Fidelity Sound Labs
Modal
Modern Classical
Modern Soul
Modular Synthesis
Moki Cherry
Mono
Mort Garson
Motown
MPB
MTV
Munich
Music Blog
Music from Memory
Music Interior
Music Therapy
Music Video
Mwandishi
Narrative
Neptunes
New Age
New Music
New Wave
New York
News
Nico
Nina Simone
No Wave
Noise
Non-Profit
Northern Soul
Now Sound
NTS
Nubian Pop
Nubian Soul
Numero Group
NYC
OBI
Obscure
Obscure Sound
On Screen
On-U Sound
online radio
Opera
Organic
Organic Music
Ornette Coleman
Ortofon
Oswalds Mill Audio
Outsider Pop
Overtone Singing
Painting
Painting with John
Pandit Pran Nath
Paradise Garage
Pastoral
Patrick Cowley
Paul Horn
Paul McCartney
Pauline Oliveros
PBS
Penguin Cafe Orchestra
Pensive
Percussion
Pharoah Sanders
Phillip Glass
Piano
Pioneer
Plantasia
Plants
playlist
Playlists
Plinth
Podcast
Political
Pop
Pop not Slop
Pop Rock
Popul Vuh
Post Bop
Post Rock
Post-Punk
Post-Rock
Power Pop
Premiere
Prince
Private Press
Producer
Productions
Professor Longhair
Prog Rock
Progressive
Progressive Rock
Prophet-5
Proto-techno
Psychedelic
Psychedelic Rock
Psyhedelic
Punk
Qobuz
Quadraphonic
QUARK
Quiet Storm
R&B
Radio
Raga
Rare Groove
rca victor
Receivers
Record Fair
Record Label
Record Stores
Record Stories
Reggae
Reggaeton
Reissue
Reissues
Releases
Religious
Remix
Retrospective
Rock
Rocksteady
Roland
Roland Kirk
Roller Skate
Room Recordings
Room Treatment
Roots Reggae
Rotary Mixers
Rough Trade
Rudy Van Gelder
Ryuichi Sakamoto
Ryuichi Sakmoto
Sacred
Sade
Sam Gendel
Samba
Samples
Sci-fi
Séance Centre
Seefeel
Sensual
Shamisen
share
Shibuya-kei
Shoegaze
Singer-Songwriter
Sisters with Transistors
Sly & Robbie
Smooth Jazz
Soft Rock
Solid State
Songwriting
Sonny Sharrock
Soul
Soul-jazz
Sound Collage
Sound Installation
Soundsystems
Soundtrack
South Africa
South African
South America
Space Rock
Speaker
speakers
Spiritual
Spiritual Jazz
Spoken Word
Staff Picks
Steely Dan
Stereolab
Stereophile
Steven Halpern
Stevie Wonder
Stoner Rock
stores we love
Stories
Streaming
Street Soul
Studio One
Sun Ra
Sunn O)))
Surround Sound
Susumu Yokota
Suzanne Cianni
Suzanne Kraft
Swamp Rock
SYNG
Synth
Synth Pop
Synth-pop
Synthesizer
Synthwave
Taarab
Takoma Records
Tangerine Dream
Tape
Tapes
TD-160
Techno
Techno Pop
Television
Terry Callier
Terry Riley
The Beatles
The Broad
The Loft
The Meters
The Mizell Brothers
The Music Center
The World Stage
Theater
Thelonious Monk
Third Side Music
Third Stream
This Mortal Coil
Thorens
Tim Sweeney
Too Pure Records
Total Luxury Spa
Traditional
Tribal
Trip-hop
Tropical
Tropicalia
Tuareg
Tube
Turntable
TV
UK
Underrated
Val Wilmer
Vandersteen
Vanity Fair
Velvet Underground
Vice
Video
Vince Guaraldi
Vintage
Vintage Gear
vinyl
Virginia Astley
Visible Cloaks
Visual Art
Vocal
Vocoder
Wackies
Walearic
Wally Badarou
Water
Website
Werner Herzog
West Africa
West African
Windham Hill
World
Wrecking Crew
Yacht Rock
Yamaha
Yasuaki Shimizu
Yellow Magic Orchestra
Yma Sumac
YouTube
Zamrock
Zither