The Technofile Web site has moved.

Technofile is now located at
Please update your links, bookmarks and Favorites.  

dbx 700: Best recording device you can buy

technofile  by al fasoldt

Columns and commentaries in a life-long dance with technology

Simple gray rule

dbx 700: The best recording device you can buy

By Al Fasoldt

Copyright © 1986, The Syracuse Newspapers

Compact discs and studio tape recorders alike use a digital technique to store sound waves. The process is called Pulse Code Modulation - PCM for short.

PCM works fine in most respects, but it has just enough drawbacks to keep some engineers searching for a better way. At one American company, that search has led to an entirely new kind of digital recording system.

The new technique is called companded predictive delta modulation. Don't worry about trying to remember the tongue twister; the results are what count, and they are spectacular.

For the last few months I have been making dozens of recordings using this new device, which was loaned to me by dbx Inc. The device, called the Model 700 Digital Audio Processor, is an unusual product for dbx, which is best known for its consumer noise-reduction equipment.

I was also able to listen to a few original studio master tapes made on the dbx 700. The sound of those tapes convinced me that dbx has come up with the single best recording device that money can buy.

I mention money right up front because the Model 700 is not the kind of thing you pick up on a Saturday morning impulse. It costs $4,600, and the price doesn't even include everything you need to start recording.

The major part you have to supply on your own is a video cassette recorder. The Model 700 gets around the difficulties of storing the bits and bytes of digital impulses by changing them into video signals that can be captured by any garden-variety VCR will do.

This means that any video recorder - VHS, Beta, or the professional format, U-Matic - can be turned into a digital recorder. It also means that each recording can play for up to eight hours, which is about seven times longer than a compact disc can play.

The comparison between a compact disc and a dbx digital tape is a fair one to make. Here's how they stack up:

The dbx digital-format tape has a greater dynamic range - the difference between the loudest and the softest sounds - by a margin of about 14 decibels. This is a huge difference, and is about twice as much as the difference in noise between a Dolby cassette tape and an ordinary one.

The dbx digital system can handle sounds that are too loud for the PCM system used in compact discs. Like a good cassette deck, the dbx 700 can handle such signal overloads gracefully. A PCM system will "crash" or fall dead silent in such situations.

The 700 does not need the elaborate filters used in compact disc players.

These filters keep certain very high pitches from interfering with the music, but they also cut off some of the highest musical sounds, too.

The 700 virtually ignores tape dropouts and other problems in the recording medium. A compact disc, on the other hand, can be unplayable if it is scratched - especially if the damage obscures the area containing the disc's coded track information.

But before you call your banker or wonder if you could do without the family car this year, you should realize that the dbx recording system is strictly a roll-your-own affair. There will never be commercial recordings in the dbx format as there are on compact disc, since even dbx recognizes that CDs are far too entrenched.

The sole market for Model 700 is the professional recording studio. Some pros are already using dbx 700 processors to replace their open-reel non-digital recorders, and others are choosing the Model 700 over professional PCM tape recorders.

As dbx 700s come into greater popularity among the pros, they will be used to record the master tapes for some commercial CDs, phonograph discs and cassette tapes.

At least one audiophile-quality cassette recording based on a dbx 700 master will soon be released on a small label, and the venerable Musical Heritage Society is scheduled to release a series of disc recordings mastered on the Model 700 this summer or fall.

The tape that will be available soon is a collection of performances by Solid Brass, a 10-piece ensemble, recorded during concerts in the cathedral-like Crescent Avenue Presbyterian Church in Plainfield, N.J.

A clone of the master tape of the Solid Brass release was among the recordings I played on the Model 700, and it ranks as one of the best recreations of brass instruments I have ever heard.

The MHS releases - on vinyl discs and CDs, too, if all goes as planned - will include a complete set of Beethoven's sonatas for violin and piano performed live by Robert Mann, first violinist of the Julliard Quartet, and Stephen Hough, a young recitalist.

If the Beethoven sonatas are released on compact disc, they will be the first digitally derived CDs not recorded on a pulse-code modulation system.

For information on how to order the Solid Brass cassette, write to Doug Haislip, 744 Fairmount Avenue, Chatham, N.J. 07928. You can get information on the Model 700 from dbx Inc., 71 Chapel Street, Newton, Mass. 02195.

 Image courtesy of Adobe Systems Inc.technofile: [Articles] [Home page] [Comments:]