DIY Web Sites
Humble Homemade Hifi - Tony Gee - Several DIY designs. Also other interesting speaker design info and lots of series crossovers
MurphyBlaster Productions - Several designs including the new Vifa Tower, Usher 2 way, MBOW1 and MBOW1 three way designs
audioDIYcentral - Audio/speaker do-it-yourself news, information and design. Great site!
Parts Express Project Showcase
Zaph Audio - Formerly John Krutke's Audio Projects Page. Great resource for general speaker design info and great low cost projects
Mark K's Speaker Pages - Great resource for driver distortion measurements
David Ralph's (dlr) Speaker Pages - Lots of great info including using felt to reduce diffraction
John Kreskovsky's Home Page - Transient Perfect Speaker Design. Also lots of great speaker design articles and the NaO kit
ARGOS Audio - Andy G's site with lots of series crossover information and lots of curved speakers
ESP - Elliot Sound Products - Audio electronics projects
Gydotron's Home Page (not in English)
Kai Audio - DIY Loudspeakers and Speaker Building Resources along with DIY event summaries
Eric Wallin's DIY page - Speaker Workshop Jig and info
D-web DIY speaker designs
Pjay's speaker building page - lots of DIY info and projects
Jon Risch - Lots of great articles on different aspects of audio systems and designs
A WATT/Puppy clone speaker design
Linkwitz Lab - Loudspeaker Design
Robert's Projects Page
Ronald Milligan's DIY Speaker Page
Steve D's Audio page - Home of the original Bob dipole speaker design
Brines Acoutics fullrange speaker projects
MFK Projects - lots of driver measurement/distortion data
Butterfield Audio
Claudio Negro's Homepage - Great Speaker Workshop information source
Keith Kidder's Audio Site
Lou's Speaker Site
Ted White's Home Theater Page - 7 Proteus jr. speakers!
Paul O'Neal's speaker projects - A few nice speaker designs

Speaker Kits
Several highly regarded speaker kits including line arrays all designed by Rick Craig
GR Research Loudspeakers and Audio Electronics. Several nice kits designed by Danny Ritchie
Salk Sound - Home of Jim Salk's Veracity loudspeaker. Several complete designs for sale. Jim's cabinets are astonishing
Ellis Audio home of the 1801b two way Seas Excel speaker kit
Bamberg Engineering Sound Lab - High end kits

Madisound Speaker Components
Parts Express
Sonic Craft High-End Speakers and Speaker Parts
Adire Audio
Meniscus Audio - Speaker parts and kits
GR Research Loudspeakers and Audio Electronics - Very High End Components and Kits
Ellis Audio - Hiquphon tweeters and 1801 speaker kit
Creative Sound Solutions - Loudspeakers, Parts and DIY Speaker Kits
Speaker City
North Creek Music
Joe Woodwooker - Great Veneer supplies (raw veneer only, pictures on site)
B&B Rare Woods - Great source for raw veneer with good prices as well

Driver Manufacturers
Danish Sound Technology - Makers of Peerless, Vifa, and Scan-Speak drivers now owned by Tymphany
SEAS Loudspeakers
Morel USA
Morel Speakers

Speaker Design Tools
Jeff Bagby's Passive Crossover Designer (Excel)
Speaker Design Calculator
Speaker Workshop
FRD(Frequency Response Data) Consortium - Excellent speaker design tools/spreadsheets
Bodzio Software - SoundEasy speaker design software
LSPCad speaker design software
PCABX Ear Training tools
Room mode / Standing wave calculator
LinearX - LEAP speaker design software
kX Project - Soundcard Drivers
Excel Crossover Design Tools
Virtual Audio Labs

Misc. Audio Info
LDSG Index - Loudspeaker Designer's Selection Guide
True Audio Tech Topics
Tons of tube related links
Art Ludwig's Sound Page - Lots of speaker related audio info.
Transmission Line Speakers and other info... check the "Technical Articles" section for great info
Barry's Coilgun Design Site - Inductor Coil Winding Apparatus
Single Driver Website - focuses on fullrange driver designs with a great links/software section
JPO Speakerbuilding Linklist
World Audio Design - Tube amp and other audio kits
Unit Conversion Factors
Acoustic Reality Series Crossover Design
LC Audio Technology 2.5 way crossover design
Speaker Workshop Project Tutorial
A detailed Speaker Workshop Tutorial
John Dunlavy discussion archive links
Fletcher-Munson Curve Explaination
Loudspeaker Phase Distortion - Is it Audible?
Phase coherent crossover networks - Nelson Pass
Dunlavy Audio Design information
Aloha Audio - Art of Speaker Design section
Audio Engineering Society - Journal Preprint Search Engine
Vintage Altec Lansing information
Shavano Music Online - Air Core Inductor Calculator
Homemade Router Circle Jig
Audio Test Signals
Thiel Audio loudspeakers design principles
Sound Demonstration Files
Speaker Workshop tutorial using FRD tools
Dynaco A25 information
Enjoy the music . com - Hi end audio equipment and music review web site, Hi Fi news
John Kreskovsky's Series vs. Parallel Crossover Experiment
Patent - Crossover Filter Design
DSP crossover design
Jason Cuadra's Elliptic Filters
Quarter Wavelength Transmission Line Loudspeaker Design
Telarc Surround Sound System Setup Guide
Passive Crossover Networks Guide
Loudspeaker Database
Woodweb's Veneer Forum