Continuing down the signal chain of my recent trope of studio gear emulation plugins, it seems only logical to begin a discussion on analogue tape machines and their plugin counterparts.
In my last tutorial I examined analogue mixing desk plugins which attempt to impart many of the audio characteristics of various real world consoles onto a piece of digital audio.
The tape plugins are non-different in this respect but employ a far wider range of controls as they attempt to emulate a far wider range of tape related audio peculiarities. This tutorial focuses on some of the mechanics behind real tape and introduces you to the sights and sounds of some of the best emulations available.
Background Noise
One of the more interesting points regarding tape machine effects is the fact that the auditory nuances of tape were never considered effects in there own right until after the digital audio revolution.
Up to that point recording to tape and imparting saturation, flutter, EQ bumps, etc. onto incoming audio were simply accepted artifacts of the necessary and final step of the recording process. If you were recording music you were recording to tape and if you were recording to tape you were recording the tape machine's artifacts.
Once things began to go digital in the late '70s and early '80s, that premise no longer necessarily held true. Although it did take some time to perfect the digital audio tape format, recording engineers were no longer tied to audio tape as a sole option of recording medium.
As the ease of use, audio quality and available track numbers increased and cost dropped, many top studios increasingly moved towards the new technology and left behind the noisy, cumbersome, expensive and labor-intensive tape machines of old.
Fast-forward to today and we are seeing an analogue backlash from this ubiquitous movement towards digital in all aspects of music production, mixing and recording.
Engineers, musicians and consumers alike began yearning for the indescribable warmth of older recordings which had been sterilized by the zeroes and ones of the digital format.
Gearheads dusted off the old units while software companies turned to digital emulations of those units in order to stay relevant in the revived analogue market.
Waves and Kramer
One of the top contenders in the analogue emulation field is Waves. The high quality coding and SoundGrid integration of their plugins have made them a staple throughout large scale and bedroom studios alike.
Although they have a few tape emulation plugins to choose from, I tend towards the Kramer Master Tape which is modeled after an Ampex 350 valve tape machine.
The Tape Speed Switch in the upper left offers two of the most common tape speed options. Tape speed measures how quickly the tape runs across the record head in inches per second (ips).
Due to the physics behind sound and magnetized recording, frequency response varies according to tape speed. The lower 7.5 ips option will result in a more bottom heavy recording with a more severe high frequency roll off. The 15 ips option will tend towards a recording with lower noise, higher overall fidelity and a less noticeable boost in the lower range.
Bias is an ultrasonic signal that is added to the audio signal in tape recording in order to regulate some of the nonlinear artifacts introduced during the recording process. It may be a little counterintuitive that we are purposefully using a tape plugin to introduce nonlinearities and then using bias to decrease them, but using it works wonders and can go a long way in cleaning up some overly dirty output.
When active in the Kramer model, the Bias Switch emulates the addition of 3dB of ultrasonic alternating current signal into the machine beyond the manufacturers originally recommended level.
The Monitor/Repro button (repro is short for reproduction) allows monitoring pre and post tape. Monitor includes the pre-tape tube and pre-amp effects of the plugin while the Repro mode adds the various post-tape artifacts one would here if listening to a play back of the recording on the machine.
The Record/Playback Level dials are input and output gain knobs which can be linked with the center button. By pushing the Record Level harder, the sound will be more obviously affected by the plugin and color the sound much more dramatically. It is pretty easy to push serene saturation into animalistic distortion here so watch out and use caution. The Link button (chain image) is a good failsafe in this regard.
The Flux control emulates the level of magnetism emitted from the record head onto the tape. In real tape recording the higher the magnetism the more strongly the magnetized particles of the tape are effected. The stronger these particles are effected the less noise and more useable signal is recorded. This holds true up to the point the magnetism distorts the tape itself and you are left with...well, distortion.
Due to the imperfect nature of the mechanical parts of a tape machine, the motor is not going to run at a perfect 15 ips over time and the tape is not going to undergo a completely stable magnetization over time. The artifacts caused by these modulations are collectively known as wow and flutter.
Real world tape machines strive to do away with wow and flutter. Most emulations offer it as a control to add as little or as much of the modeled artifacts as desired which can be done here with the Wow & Flutter dial.
Although the Noise control does add tape noise as one would expect, in the instance of the Kramer Tape, it is a two tiered mixture of both tape hiss and valve noise inherent to the machine's physical components.
A dry loop.
The Kramer at a moderate setting. I can really hear a saturated low-end and subtle compression on this one. The snare roll off is pretty nice too.
Slate's Contribution
Unique to the Slate Tape Machine is a switch in the upper right to choose between emulations of a 16 track Studer A827 tracking tape machine and a Studer A80 RC master tape machine.
Both are highly revered machines known for deep, rich and highly detailed recordings. As Studer strived for as authentic a reproduction and transparent a coloration as possible, both emulations tend towards a fairly flat and clean response which lends itself to material of all types.
Directly below is another switch to choose between FG456 and FG9 tape types. The FG456 is a classic tape type with a fairly colorful saturation while the FG9 is a more modern tape which tends to be cleaner and punchier.
The Bass Alignment slider (revealed after clicking the Settings button in the upper left) controls the level of the bass bump while the Noise Reduction slider controls the level of modeled tape noise. The Wow and Flutter control is self explanatory and is the same as in the Kramer model.
One of the great things about the Slate tape plugin is that you can group multiple instances of it across multiple channels to easily model a tape tracking session and control the multiple instances with a single click. The overall and individual group levels can be manipulated in the Calibration Levels box which is front and center. The groups are set by clicking the Group Box (reads ungrouped) on the main interface.
Directly to the right you can choose to mute the the tape noise when no sound is running through the plugin, choose how quickly the VU meters respond and select the default group new instances of the plugin will adhere to.
The dry loop.
The Slate at a moderate setting. This seems to have a bigger bottom and heavier roll off than the Kramer. I'd probably go back and re-emphasize some of the highs pre-tape.
Other Considerations
On the extreme side of tape emulation offerings are Universal Audio's try at a Studer emulation, the A800, and the U-he Satin which attempts to recreate a number of different classic machines.
These are two of the most feature rich emulations out there and allow the user to literally get under the hood and virtually calibrate them. A mini novel would have to written to get into the details of both of these plugins and as we are getting short on space, I would highly recommend checking out both manuals for some useful and detailed information. The Ampex model by Universal Audio is well worth a look into as well.
The dry loop.
The Satin at a moderate setting. This one is pretty transparent with a subtle saturation being the most noticeable effect. This thing can crush audio also and do a million things in between.
The Studer at a moderate setting. This is pretty transparent also with a good bottom, nice saturation and great compression. This may be my favorite of the lot.
Although subtlety is usually key, these units can be pushed to immense levels of distortion to be used however you may see fit. Although it can be difficult to justify spending hundreds of dollars (the Universal Audio emulations clock in at around $300 and runs only on proprietary hardware) on something that is hardly noticeable when used properly, these emulations can add an earthiness and cohesion to your digital sound at a fraction of the cost of a real unit and are something most will want to seriously consider when fully fleshing out their digital studio.
