audioXpress - November 2017

14 Midwest Audiofest 2017
Outstanding DIY Speaker Designs
By Thomas Perazella
Thomas Perazella provides an insider’s view as one of the three judges at this year’s Speaker Design Competition held annually during the Midwest Audiofest.

30 OPPO Digital UDP-205
A 4K Ultra HD Audiophile
Blu-ray Disc Player
By Gary Galo
Get an in-depth look at OPPO Digital’s new high-definition Blu-ray disc player, the UDP-205, which Gary Galo confirms is a new reference for stand-alone digital players.

40 Ultimate Ears Pro Sound Tap Personal Monitoring System
Your Own Easy-to-Use In-Ear DI Box
By Stuart Yaniger
Stuart Yaniger puts Ultimate Ears (UE) Pro’s Sound Tap to the test to see how well it performs when relaying sound.

44 Design Considerations for the Optimum Digital
ANC Headphone
By Peter McCutcheon
Learn more about the constraints associated with active noise cancelling (ANC) and the design best practices to compensate for them and maximize bandwidth.

48 Measurement of Devices That Use AGC
By Adam Liberman
Adam Liberman discusses the test and measurement of audio devices that feature built-in automatic gain control (AGC) and offers some advice about optimal test settings.

56 Build Your Own Oscillator
This is a 1 kHz Device with Less Than
2 PPM Distortion
By Dan Joffe
Dan Joffe explains how to build a 1 kHz oscillator with low distortion for less than $100.
IT’S ABOUT THE SOUND
8 Vinyl vs. CD (Part 2)
Repeated Measurements
By Ron Tipton

SOUND CONTROL
24 Reverberation: Friend
or Foe?
By Richard Honeycutt

Hollow-State Electronics
60 Concept Design for a Small Bass Amplifier
By Richard Honeycutt