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Remember, this transfer that you (or I) are about to undertake may be the last time (and hopefully the best time) that the original is transferred. Here are some suggestions:

1. Make at least two masters and a listening copy. Keep one set of masters off-site. //

2. Make straight transfers before processing. Save these as better noise processing algorithms may be available in the future.

3. Save a good portion of the noise footprint on the tape without other signal information for later noise reduction processing.

4. At first, worry less about a final product than getting a good, clean transfer with as few artifacts as possible.

5. Above all, listen…are you getting the best transfer you think you can?

If the restoration/preservation reformatting is for an institutional client, then the first transfers should be as unprocessed as possible — at least the initial copies that are archived should be done that way. The main reason for this is that processing algorithms will always get better and they may hide some information that is useful to future researchers–information that today we consider “noise.”

I am conservative when setting audio levels when making transfers because there is no way of knowing the loudest portion of the signal in advance. So I generally transfer at 24 bits and then raise or normalize the level prior to dithering down to 16 bits for the distribution copy. If I’m working on music, I will generally archive the 88,200 ks/s or 96,000 ks/s files before the normalization.

Processing should generally be done on a copy. The exception to this in my mind are private clients who want the best possible copy of their parents’ wedding, or some other important event. If applied conservatively, noise reduction and equalization will be appreciated by these clients and most of them won’t care a bit that it’s been processed. I keep the unprocessed files on my servers until I am sure the client is happy with the processed version.

As to what to use, there are a wide variety of options available. At the high-end, this falls into the category of “remastering” rather than simple restoration and I’m sure there are options that I’m not aware of.

As a first step, I am very pleased with the basic capabilities built into Samplitude. In addition to that, I use Algorithmix Noise Free Pro as well as the Sound Laundry suite. Really tough projects can often be improved by the filters in Diamond Cut 6 Live/Forensics and most of the filters are available in the lower-priced Diamond Cut 6. Diamond Cut and their main dealer, Tracertek, often run sales which was how I upgraded to Live/Forensics.

Other products with excellent reputations are Cedar Cambridge, Quadriga Audio Cube, and many others. Listening to and discussing with other users via one or more of the mailing lists listed here is very useful.

It seems some people new to tape are confused over how to align a tape recorder. This is the abbreviated version.

If you want to record on a tape recorder (and I do not recommend doing that these days as you’re just generating more tapes that will need to be transferred later) the first thing to do is get the playback correct. //

Anyway, I think that quality digital recording will capture sounds closer to the original than analog magnetic tape. This has been true in most tests run since the early days of digital recording and why most of the classical engineers who are looking for accuracy and not colouration were early adopters of digital. If you wish to record on analog that’s wonderful, but consider that analog tape is being used as much as an effect or sound-colourant as it is a storage medium. Also, remember that your legacy of tapes will be much more costly to preserve and migrate than digital files, although they may withstand neglect better.

There are complex interactions between tape speed, track width, frequency response, and dynamic range. This article is an attempt to summarize the major influences.

Exact Audio Copy is a so called audio grabber for audio CDs using standard CD and DVD-ROM drives. The main differences between EAC and most other audio grabbers are :

• It is free (for non-commercial purposes)
• It works with a technology, which reads audio CDs almost perfectly. If there are any errors that can’t be corrected, it will tell you on which time position the (possible) distortion occurred, so you could easily control it with e.g. the media player

With other audio grabbers you usually need to listen to every grabbed wave because they only do jitter correction. Scratched CDs read on CD-ROM drives often produce distortions. But listening to every extracted audio track is a waste of time. Exact Audio Copy conquer these problems by making use of several technologies like multi-reading with verify and AccurateRip.

The International Association of Sound and Audiovisual Archives (IASA) has released their landmark Guidelines on the Production and Preservation of Digital Audio Objects as a free web (HTML) edition, available here. http://www.iasa-web.org/tc04/audio-preservation

A variety of noise reduction processing was used This processing was a double-ended system where the record processor boosted certain frequencies and portions of the dynamic range while the playback processor provided a complementary reduction of the signal. These systems are generally referred to as companders for compressor-expander. Two different manufacturers of companders achieved high market penetration. Two others did not, but that is not to say that their equipment was not used somewhere. To the best of my knowledge, no one has written a Direct-X-type plug-in for a computer, so you are stuck having to buy the playback processors for each system you wish to reproduce.

At some point, this tape was played on a 1/4-track machine that injected hum onto the left channel. Here’s what the magnetic viewer showed:

At the very top we can see a remnant of the left channel material, then the 120-Hz bars (62.5 mil spacing), then the remainder of the left channel material. In the middle is the guard band and at the bottom, the right channel.

I finally figured out how to power the Sennheiser MKH-104, 404, and 804 from 48 V phantom power (P48) which is very common on professional and many prosumer mixers and recorders. The MKH-X04 series requires -8V for operation. Please note that some portable recorders do not generate P48 even on their XLR connectors. This will not work with P12 or P24 inputs. It works like a charm on P48 inputs (at least from Mackie, Yamaha, and Sound Devices). Thanks to everyone for their input and assistance.

Today, 48 V phantom powering is almost universal. In phantom powering the positive voltage is fed through a pair 6k81 ohm resistors, one to each modulation lead. The matching of these resistors is often done to 0.1% to maintain common mode rejection. The negative power runs on the mic shield. XLR: Pin 1-shield; Pin 2-audio hot, +48 V; Pin 3-audio low, +48 V. Tuchel: Pin 1-audio hot, +48 V; Pin 2-shield; Pin 3-audio low, +48 V. This was standardized in the 1960s in DIN Standard 45596. //

Prior to standardization, in 1964, Schoeps produced the CMT-20 microphone which used negative 8.5 V phantom power. The CMT-200, according to Schoeps drawing SB316, dated 1964-10-14, used the same -8.5 V phantom. Later this was broadened to negative 8-12V phantom followed by the switch to positive phantom at some later point. With vintage microphones, at least from Schoeps, be very careful as they might be negative phantom.

(free) 333-page technical document on sound restoration titled "Manual of Analog Sound Restoration Techniques." It's written by Peter Copeland of The National Sound Archive in England (part of the British Library Board), and it's a remarkable and interesting document.

I don't agree with everything Copeland says, but he makes a number of good points in his report, and there's a lot of very good information in it, particularly on vinyl restoration techniques. Apparently Copeland died in 2006 without finishing the manuscript; parts of it are in desperate need of editing, and the info is dated in sports, but there's still a treasure-trove of good information there. Note that Copeland's approach is very scientific and engineering-based; subjective audiophiles may take issue with some of his opinions.

It's available as a free PDF at this link:

http://www.bl.uk/collections/sound-archive/pdf/analoguesoundrestoration.pdf

Copeland reportedly put about ten years of research into writing the document, and it's very well-done. Anybody who's trying to do restoration and mastering of vinyl, 78RPM discs, and analog tape should read it.

https://web.archive.org/web/20080920161543/http://www.bl.uk/collections/sound-archive/pdf/analoguesoundrestoration.pdf

The late Peter Copeland wrote a handbook concerning analogue sound restoration. It is required reading. When Peter died in 2006, I despaired that this would ever see the light of day. In 2008-09, the British Library released it as a free PDF file available here.

The IASA “Green Book” TC-04 Guidelines on the Production and Preservation of Digital Audio Objects can be purchased from IASA. The Second Edition is available online.

The CoOL (Conservation On Line) site has many resources. In particular, read Gilles St-Laurent’s 1996 article on The Care and Handling of Recorded Sound Materials.

The National Recording Preservation Board of the Library of Congress and the Council on Library and Information Resources March 2006 Capturing Analog Sound for Digital Preservation: Report of a Roundtable Discussion of Best Practices for Transferring Analog Discs and Tapes

This Tape Timing Chart is approximate. Most reels will contain a bit more tape than indicated time implies, typically about 6%. The footage is actual.

These timings are for one program. There can be as many as four mono programs on one 1/4-inch tape.

This document discusses the speeds used for most analog magnetic tape recording.

See the tape timing chart to convert speeds and lengths into times.

Note throughout most of the rest of this document we are using the correct ISO form of in/s instead of i.p.s. which is the traditional way of stating "inches per second".

One of the challenges for good sound reinforcement or speech recording is keeping the speaker “on mic”. There are many ways of handling this, but some work better than others. Here are my favourites:

• If the room is quiet and you can do a proper setup, a pair of Sennheiser MKH-416 short shotgun mics, one for the interviewer and one for the interviewee, gives very natural and unselfconscious results.
• For larger groups, I’ve had good results with an Audio Technica AT-822 (or the phantom-powered AT-825) stereo microphone, but the actual voice quality of that mic is inferior to the MKH-416. The high-end is harsher, but, used at a greater distance that is often not as noticeable. The room needs to be very quiet for this to work well, however. This is currently my least favourite approach (of those listed).
• So far, some of the best pickup I have found is a headworn mic–the main subject of this post.

At our church, they had tried headworn mics from Shure and they really were uncomfortable. Whoever selected the units, selected dynamic units and they did not sound all that good. They were retired in favour of the Countryman E6 units (also available from Shure, although I prefer the direct-from-Countryman version with the 2mm cable for robustness).

The Countryman units were working reasonably well, but never seemed to stay in the same place. It was frustrating as it was causing a widely varying sound quality, so we decided to try a DPA 4066 headworn mic on our head priest. The results were outstanding. The unit is comfortable (no more sore ears), it stays put, and it sounds better!

It is no surprise that these are taking over the religious and theatre markets.

The benefits of using a voltage audio transmission system in broadcast facilities is investigated. State of the art microphone preamplifier requirements and an ideal voltage system distribution amplifier are outlined. The application of the Peak Program Meter to the new systems and the modified installation at WABC-TV are covered.
Introduction

Over the years, many audio practices have been followed without anyone asking WHY? or IS THERE A BETTER WAY?

The [then (i.e. 1980)] present [but now deprecated] standard for Broadcast Audio Systems is EIA Standard RS 219 [1]. In light of the fact that the [then] current standard was published in 1959 (and this was merely a reaffirmation of an earlier standard), one might imagine that in relation to today's common audio practices, it is somewhat archaic.