Table of contents
- Audio Digitising of Analogue Tapes
- About the equipment
- Digitising Cassette Tapes
- Digitising Reel-to-reel Tapes
- Additional Resources
🚧 This page is currently under construction 🚧
Last updated: 26 November 2021
This page outlines the technical workflow for audio digitising for the PARADISEC unit based at the Australian National University. This workflow can be modified to accommodate other organisations in their specific digitising goals.
The ANU PARADISEC studio utilises a high-performance DELL OptiPlex 7080 Tower PC workstation with the following specifications:
|Processor||Intel Core i7-10700 (8-core, 16MB cache, 2.9GHz to 4.8GHz, 65W)|
|Drive||M.2 512GB Class 35 Solid State Drive|
|Drive||2.5in 1TB 7200 Hard Disk Drive|
|Drive||8xDVD +/-RW 9.5mm Optical Disk Drive|
|Full-size Tower||SSF (Small Form Factor) will not accomodate necessary soundcard|
Soundcard: RME HDSPe AIO Pro
A new soundcard needed to be added to the DELL tower to provide us with the necessary input and output connections and meet the high-level specifications set by our industry’s peak-body: IASA (the International Association of Sound and Audiovisual Archives).
- D-sub 9-pin socket (for the Digital Breakout Cable: AES/EBU & SPDIF)
- up to 192kHz/24-bit, balanced stereo in/output
- a high quality digital audio stream synchronisation mechanism
- allow the transfer of a digital audio data stream having undergone no change or alteration
AD/DA Converter: RME ADI-2 PRO FS R Black Edition
Having an external, stand-alone analogue/digital converter is critical so that the following specifications can be met (see IASA link below for the precise parameters for each):
- Total Harmonic Distortion + Noise
- Dynamic Range (Signal to Noise)
- Frequency Response
- Intermodulation Distortion
- Amplitude Linearaity
- Spurious Aharmonic Signals
- International Clock Accuracy
- External Synchronisation
READ MORE ABOUT analogue to digital converters and sound cards in sections 2.4 and 2.5 of IASA’s TC04: Guidelines on the Production and Preservation of Digital Audio Objects.
Audio cassette player: Tascam 122 mk III
READ MORE ABOUT the use of cassette tape machines in section 5.4.5 of IASA’s TC04: Guidelines on the Production and Preservation of Digital Audio Objects.
Reel-to-reel tape player: Revox C270
Reel-to-reel tape player: Studer A807
READ MORE ABOUT the use of reel-to-reel machines in section 5.4.4 of IASA’s TC04: Guidelines on the Production and Preservation of Digital Audio Objects.
The software we use to digitise audio is Steinberg’s Wavelab 10 Pro
Note: Avoid internet browsing and any activity over the network during digitisation (these activities can cause interference, which may result in digital clips and unwanted errors in the signal). Avoid using mobile phones or other mobile devices (better yet, turn them off), including close wi-fi transmitters, and as a precaution, close any programs other than WaveLab during recording of audio.
Turn on computer and login with your ANU UDS credentials
Resources you should find on the desktop:
- Wavelab Pro 10.0 shortcut
- Wavelab Pro 10.0 operations manual
- Turn on the RME ADI-2 PRO FS R
- Turn on and load a tape into the Tascam 122 mk III
Open the Wavelab program.
You may need to select New Project if presented with a start-up window.
Otherwise, the main Wavelab window will open up
Make sure the Workspace layout is the PARADISEC layout. Go to the banner menu at the top and select Workspace > Layout > PARADISEC
Once main window opens, go up to the banner menu again and select File > New.
Another window pops up asking you to select the template. Select PARADISEC.
A new timeline will appear in the AUDIOEDITOR window located in the lower half of the main window. In this window, select the ANALYZE tab along the top. Make sure to tick the radio button next to Audio Input
From the meter tabs in the upper right quadrant of the main window, grab the PHASESCOPE and drag it out to create a popped-out, larger window.
Look to the buttons on the bottom of the window
Press the button with the dot on it, far right. This will open the following recording window and activate the PHASESCOPE:
In Method tab under File to Create, select Named file from the drop down menu, then type in the file name you want to assign this file. Select the target location, E:\DigitisedFiles for the output files.
Play the tape as a means to test the levels audio levels to recording. These can be seen in the Recording window. Play for a minute or so, making sure the signal stays below -12.00 dB.
If the signal on the tape is too loud, you should adjust this on the TASCAM using the OUTPUT dial on the far right of the tape machine. The dial should be on 8 to begin with. Make adjustments from there.
Once you adjust the volume, press the Reset button underneath the audio levels back in Wavelab so that you can confirm you have adjusted the audio adequately.
As you are previewing the tape, you can see that the PHASESCOPE is also actively monitoring the audio. We will use this scope to help guide us in our Azimuth adjustment.
You can find the Azimuth screw on the TASCAM machine in the gap right above the STOP button. It is the screw to the left of the heads. Use the supplied tiny screwdriver.
READ MORE ABOUT Azimuth adjustments in section 5.4.12 of IASA’s TC04: Guidelines on the Production and Preservation of Digital Audio Objects.
Confirm the PHASESCOPE is active. There will be a gently moving circle of random noise (see image below).
Play the tape. Once the signal is clearly coming through, turn the screw to the left and to the right, using your ears and the phasescope to help you determine the clearest signal. If the tape is a cassette tape the same signal will be on both channels. Aim to get the line as vertically straight as possible (see image below).
- Once you get the cleanest, most vertical line you can, rewind the tape, press Record in Wavelab, then press play on the TASCAM and begin digitising the tape. Remain nearby to monitor the progress of this task; keep in mind that something could go wrong as the tape is being played. If you remain nearby you can
Put the tape reel onto the left spindle, the right is reserved for the take-up empty reel. Make sure tape is spooling off to the left of the reel. Once on the spindle, lift top of the spindle and turn it so that the tabs can lock down the reel.
Bring down the tape leader (the extra bit of non-magnetic tape at the beginning of the reel, usually green) and thread it through the various rollers as below.
Once threaded through, if digitising on the Studer, flip up the head shield. The shield flips up automatically when play is engaged on the the ReVox.
Move the reels manually along until the point where the tape leader ends and the magnetic tape begins almost reach the tape heads.
Reset the counter so that it reads 00.00.00.
Follow the same WaveLab instructions as above for testing the volumes of the output. To adjust the output volume, make sure the UNCAL light is on. This means the audio volume is uncalibrated and you can adjust volume as needed using the CH1 and CH2 REP/SYNC LEVEL
Check the speed of the playback. If it sounds too slow or too fast, cycle through the choices of 3.75, 7.5 or 15. If these do not appear to create the right speed, make note and we may need to adjust once audio is digitised.
Adjust the azimuth for opem reel tapes
If the tape you are digitising is recorded as mono, but there is signal only in one channel, you will see the line is at a 45° angle, leaning toward the left or the right, depending upon which track the mono signal was recorded on (see image below).
Many tapes we receive were recorded as mono, but on both sides of the tape. We digitise these two tracks simultaneously. As a result, there will be an X shape for representing both mono tracks. As the audio for both tracks is playing simultaneously (one track will play normally, the other will be reversed), you will rely more on the phasescpoe to adjust the azimuth (see image below).
Once everything has been checked and adjusted. stop the reel from playing.
Get WaveLab set up to record the track, following the instructions as outlined above (specifically: step 16).
NOTE: It may be the case that the tape has been recorded as mono tracks on both sides. Our system will digitise both mono tracks simultaneously. If you are using headphones, you will hear one track in one ear, playing correctly, and the second track in the other, playing backwards.
When the tape is coming to the end, watch closely and stop playback when the magnetic tape finishes passing along the heads and the leader tape appears (usually red). Then stop the recording in WaveLab.
Press z-loc to rewind the tape back onto original reel.
NOTE: DO NOT HIT REWIND. Use the Z-Loc button. This will rewind the tape, slowing down as it approaches the 00.00.00 point in the counter. This will ensure we do not need to rethread the tape, and it is a more cautious way to treat the tape
Pragmatic Audiovisual Preservation (2021) Ashley Blewer
IASA Technical Committee, Guidelines on the Production and Preservation of Digital Audio Objects (2009, 2nd ed.) ed. by Kevin Bradley. (Standards, Recommended Practices and Strategies, IASA-TC 04). International Association of Sound and Audiovisual Archives.
Sound Directions: Best Practice for Audio Preservation (2007) Mike Casey & Bruce Gordon
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