Here we are in the year 2000 and the following question made it occur to me that many young engineers and musician's will never know the wonders and idiosyncrasies of analog recording.

"I'm using a Fostex 1/4 inch 8-track machine to record a demo for my band. If I record with noise reduction on, does it affect the sound when it is recorded to the tape or does it only affect playback?"

Many different forms of noise reduction have been developed and used over the years. Most use an encode/decode process, where the signal is altered as it is recorded to tape, and the process is subsequently reversed when the tape is played back. Dolby and dbx have been the most prominent brands of noise reduction, and with only a couple of exceptions their schemes have all been of the encode/decode variety. The Fostex 1/4 8-track machines have used either Dolby B or Dolby C (depending upon which vintage), both of which do alter the signal going to tape. Dolby does this by applying what is sometimes known as pre-emphasis to the signal before it is recorded. In simplistic terms this is basically a high frequency boost. When the tape is played back the signal is de-emphasized (high frequencies cut), which removes a lot of the noise we hear.

---

Other Techtips from January 2000:
January 31 - CD burning issues
January 28 - Live miking and mixing with multiple microphones
January 27 - Fundamentals of Noise Reduction
January 26 - Kurzweil Output Architecture
January 25 - Mixing virtual tracks into a MOTU 2408
January 24 - Running wires through sound proof walls
January 21 - Miking an upright piano
January 20 - More on hard drive head crashes
January 19 - Reversing pins 2 & 3 in an XLR cable, what does it do to Phantom power?
January 18 - Pin 2 versus Pin 3 at mic inputs
January 17 - Where have the analog mixers gone?
January 14 - How does increasing amp power affect SPL?
January 13 - The one exception on TRS wiring
January 12 - Get line level signals into a mixer without line inputs
January 11 - Magnetic Fields from unshielded monitors and your cassette deck
January 10 - Keeping rooms isolated that have wire runs between them
January 07 - More on cable wiring - balanced to unbalanced
January 06 - More on wiring unbalanced and balanced connections
January 05 - Wiring XLR to TRS connectors and reversing polarity for pin 3 hot
January 04 - More info on cable polarity and how to wire for various circumstances
January 03 - Getting that R & B booming bass drum sound

---

1997 | 1998 | 1999 | 2000 | 2001 | 2002 | 2003 | 2004 | 2005 | 2006 | 2007 | 2008 | 2009 | 2010 | 2011 | 2012