Analog Tape Basics

As promised we’ll now dive into the real meat & potatoes (or is it bits & bytes?) of recording. This article will be hands-on user oriented for analogue, with the next installment for the digital set. Here’s the basics of analogue and how it fits into your recordings.

The very first recordings were analogue. The first recorder consisted of a needle wiggling on a wax cylinder, followed by a needle wiggling on a flat disk, followed by a thin iron wire dragged through an electromagnet, followed by a strip of paper with rust on it dragged over a flat electromagnet. Editing went from impossible to pretty OK. Wax cylinders and disks couldn’t be edited; followed by wire recorders, where you cut the wire and tied knots in it for editing; followed by splicing blocks and tape that we all know too well.

Soon after tape recorders were invented, people wanted to make them portable and take music with them. Ignoring the underdash record players of the day, a few hikers in Europe started recording music on a newly invented dictaphone format, the Phillips cassette. From it’s humble beginnings as a fairly horrible sounding medium, it has been upgraded to sounding pretty darn good. Better tape formulations, more powerful noise reduction, and quieter electronics has made it the medium of choice for many of us. (We won’t segue into 8-tracks and the El-cassettes, both interesting but irrelevant to our discussion)

The original reel to reel recorder was used by consumers for a lot of years. You could even purchase albums on reel tape. These tape recorders were made by companies like Ampex and Wollensak, and sounded pretty good in their day. Once cassettes were upgraded to chrome tape and Dolby noise reduction, reel decks became too expensive and complicated for home use. But did they go away? Nope, radio stations and recording studios still use them to this day.

Here’s a list of standard analogue tape formats and how they fit into the entire recording chain.

1) Multi-track reel to reel:

Usually 1/4″ to 2″ tape with anywhere from 4 to 24 channels. The original workhorses, the Tascam 40-8 and 80-8 were the first multitrak recorders of a lot of current engineers. Price range is around $500 per track. Noise reduction on the earlier units was external dbx or Dolby A, but many of the newer units from Tascam and Fostex use internal Dolby C or dbx at a great cost reduction since external noise reduction costs around $150 (for dbx) to $700 (for Dolby SR) per channel. Multiply that by 8 or 16 tracks and you’ve got real money in NR. Tape costs around $20 per reel for 1/4″, $40 per reel form 1/2″ and $80 per reel for 1″ stock. And you get maybe 30 minutes running time on a 2500 ft tape at 15 inches per second. Yep, time is money, especially on a reel of 2″ tape.

2) Multi-track cassette:

First pioneered by Tascam with their porta-studio, everyone now has got a multi-trak cassette studio in a box. Tracks range from 4 to 8 on a standard Phillips cassette, and basic mixing board functions are usually included. Internal noise reduction is built-in and needed to help offset the limited headroom and noise floor of the cassette medium.

3) Half-track reel:

The workhorse of the radio industry, you still can find one in just about every radio station in the world! Radio spots are still distributed on 7 1/2 ips 1/4″ reel without noise reduction in all but a very few specialized cases. A good Studer, Ampex, or Tascam recorder with external dbx noise reduction is a very clean and good sounding medium that’s able to take lots of abuse. Many recording are still mastered this way, but the half-trak reel will soon be replaced by the DAT recorder.

4) Standard Cassette:

Everyone’s got one, and one size fits all! Isn’t it great when there’s a standard. You can playback any cassette ever recorded in your new whiz-bang Walkman. With tape formulations ranging from ferric (that’s iron rust) to chrome (actually chromium dioxide) to metal (that’s pure unoxidized metal particles for the purists), tapes have come a long way. Also noise reduction (ranging from least to most powerful) such as Dolby B, Dolby C, dbx type II, Dolby A, dbx type I, and Dolby SR, plus new ones like Dolby HX-Pro and Dolby SL have helped spell the demise of the vinyl record.

Why use analogue?

Well the first rule is you use what you got! Studio’s can’t afford to buy every new gadget that comes along, so you make do with what’s available. Secondly, well maintained equipment run by a competent engineer can sound pretty impressive. Even the cheaper gear can sound good, but it’s not as forgiving as it’s thoroughbred cousins. Here’s a few hints:

1) Clean your heads:

Q-Tips and denatured isopropyl alcohol are a necessity in this business. Clean them before every session, and clean them like you clean your own teeth (maybe better). Nothing is more important to good sound and long head life than cleaning. Don’t use methanol, since many tape heads use this as a base for their glue. Apparently, you can delaminate your heads if you sop on too much wood alcohol. Teac sells chrome polish for regular use on tape heads which is a favorite of mine. Just dab a little on the heads after cleaning with alcohol, and polish with a soft cloth. Teac claims it greatly reduces head wear, and I tend to agree. An engineering buddy of mine, Fran Little, swears by silicon car wax for the same use. The idea is to make the tape heads as slick and smooth as possible so they don’t scrape the oxide off the tape and further accelerate wear. If Teac and Fran both like it, it can’t be all bad.

2) Use “best” quality tape: 

I’m amazed at the tapes that hit my studio from time to time. Some of the worst junk tape you can buy is sent in as masters. Boy are they selling their project short! Even at two to three times the price of “junk” tape, premium tape is a bargain. Especially for cassettes, you’ll have better high’s, more saturation capability, and less oxide shedding for better head life. Find the most expensive brands of tape available and do a few tests on your decks BEFORE you start your recording project. I use TDK MA-X 60 for my cassette mastering, and AMPEX 456 Grand Master for both half-trak and multi-trak recording. Remember to set your bias for any new tape you use.

3) Use the most powerful Noise Reduction you have available:

I’ve had projects come in that were recorded without dbx because the “engineer” thought that you can’t mix noise reduction types and he wanted Dolby on his cassettes. That’s doo doo! If you’ve got dbx, use it. Dolby C is better than Dolby B, and any noise reduction is better than none at all. No Virginia, noise reduction does not cause a loss of highs in general. If you turn off the noise reduction on playback of a Dolby encoded tape, you’ll get an unnatural high boost along with a lot of noise. That’s where that old wive’s tale comes from. Also, Dolby and dbx can’t remove any noise from dirty mixer channels, etc…. Dolby’s and dbx’s only job is to reduce hiss introduced by the tape itself. All in all it’s a pretty good deal. But one caveat, all noise reduction is dependent on good tape. If your frequency response of the tape is down 6db at 15 khz without dbx, you’ll be down 12 db with the noise reduction turned on. You don’t get something for nothing, so use the best tape you can get and keep your decks aligned!

4) Red Riders of the Lost VU Range:

Don’t bang those needles in the red. Noise reduction means never having to say your sorry. On a cassette try to keep it around +2 VU for ferric, +4 VU for chrome, and +6 VU for metal tape. A little saturation is O.K. and can make up for a lack of limiters downstream, but don’t bury the needle, especially with highs on a cassette. It just won’t do the job and you’ll be left with a nasty mess that can’t be fixed. Percussive sounds are especially hard to record on a cassette with saturation happening when the needles barely move. LED sytle meters are much faster than a conventional meter movement in this environment, and can be a big help if available.

There’s also more leeway on a reel to reel deck running at 15 or 30 ips where +8 VU is traditionally the limit with good tape and electronics. The general rule of thumb is that doubling tape width or speed gives you an extra 3 db of noise floor or headroom. You can see why a 1/2″, two-track tape running at 30 inches per second can handle much more signal than an 1/8″ wide four track running at 1 7/8″ per second. If your portastudio has a selection for regular or high speed (3 3/4 IPS) by all means use the fast speed. Audio recording can be fun and profitable if you pay attention to the details. Unlike live performance where problems are in the past and forgotten, recordings make a detailed record of all musical and engineering problems encountered in a session. So do the best job you can so you won’t cringe every time you hear your tunes played.

That’s about all for this time…. Next time we’ll take a byte out of digital recording with a few hints for those new users. Also we’ll be going into editing both with razor blades and computers. So hold on to your DATs, the fun is just beginning…

As Published in Free Spirit Magazine – June ’93
Copyright Mike Sokol – All Rights Reserved

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