Analog Tape Effects PSE’s gone back to the future, creating tape loops and echo chambers – and now we want to show you how. By Keith Hatschek | April 2008
With the range of digital plug-ins and effects available today, the time when engineers created special effects with simple do-it-yourself techniques and tools found in any control room seems like ancient history. But these effects helped define an era of pop music. For example, Sam Philips’s slapback tape echo on early Elvis recordings and Pink Floyd’s use of tape loops are just two examples of innovative analog techniques that are worth remembering today.
This month, PSE decided to step back in time, so we dusted off an analog reel-to-reel tape machine from the ‘80s and experimented with making tape loops. Then we used the ambience found in a studio to enhance some drum and clap tracks. But let’s start with a little…
Tape and tape effects history
One of the original magnetophones brought back from Germany in 1946 by Jack Mullin is now in the Pavek Broadcast Musuem in Minnesota.
Analog tape recording was invented in the mid-1930s by German recording engineers who saw the immense benefits of being able to record and edit tape rather than rely on lacquer discs or bulky wire recorders to make masters. They dubbed their invention the magnetophone. During the Second World War, GIs listening to classical music broadcasts originating in Germany were puzzled that there were none of the clicks associated with the 16” transcription discs used to replay concerts in the U.S. on these German broadcasts. In the last days of the war, an American GI named John T. (Jack) Mullin tracked down the reason for these “perfect” broadcasts. He located a working high fidelity German magnetophone system and brought it back to the US.
In time, Mullin and a number of other U.S. technicians learned the secrets of the recorder and not long after, in 1948, a small group of technicians at the Ampex Company, inspired by Mullin’s innovative use of the magnetophone, manufactured the model 200, the first commercial analog recorder built in the U.S. Ampex brand two-track and multi-track machines are still viewed as some of finest sounding recording systems ever built.
Composers in the mid-20th century then took these developments to their next phase, experimenting with tape loops. Rather than simply using tape to document a musical performance, the loops created by cutting out a section of recorded music and splicing the front to the back – forming a loop that could be played endlessly on a tape machine – became a new compositional tool.
The Beatles' "Stawberry Fields Forever" introduced mainstream audiences to tape loops.
American composers such as Pauline Oliveros and Terry Riley embraced tape as part of their music creation process. They spliced, edited, and looped tapes, creating music that had never before been heard or conceived. By the late 1960s, the Beatles began incorporating tape loops into their recordings, with “Strawberry Fields Forever” and “Revolution #9” standing out as two of the more famous examples.
Tape loops were the equivalent of today’s samplers. Record a sound that you wanted to use as a repetitive element on a song, then simply create a loop of the proper timing and play it over and over, mixing it in and out of the song as it suits the mix. One of the most recognizable tape loop sequences is the opening series of clocks on Pink Floyd’s “Time,” from their seminal 1973 album, Dark Side of the Moon.
Some of the additional techniques associated with analog tape loops include using tape saturation to get a compressed, “fatter” signal; recording at ultra-slow speeds (1 7/8 IPS on some consumer reel-to-reel machines), which results in a dramatic roll-off of high frequencies and a distinctive “lo-fi” sound; speeding up and slowing down the tape loops to create phasing or pitch variation effects; using your fingers to pinch the loop, slowing it down a tiny bit; and poking the tape with a finger or otherwise manually controlling the tape’s path across the playback head.
Sony's TC-377 was designed in the 1970s for the home recording enthusiast. It boasts three tape speeds, front panel mic inputs and adequate specs for making analog tape effects.
One of the most interesting decks that offers a great deal of flexibility is the quarter-track Sony TX-377 three-head tape recorder, a staple of the 70s hi-fi scene, now found routinely for sale on eBay for less than $100. It offers three tape speeds, from 7.5 IPS down to 1 7/8 IPS, and front panel mic inputs with inexpensive preamps that make it easy to plug a mic or other sound source directly into it. Since it has three heads, you can also use it to create slap back echo effects, simply recording on channel one, then routing that channel’s output into the input of channel two and re recording it. The distance between the record and playback head will give you a nice slap echo. By selecting different speeds, you can vary the length of the delay and simulate that great Sun slapback echo sound. You can also use such a machine to make quarter-track tape loops.
Making a Tape Loop The recipe for setting up and making your own tape loops is pretty straightforward if you have access to an analog tape recorder, some fresh tape, and the appropriate tape splicing block. We gathered our materials together at a newly-constructed studio at University of the Pacific, which is built around a Pro Tools HD 2 system and a Digidesign C-24 mixer.
I invited two local engineers, Jeff Crawford and Spencer Johnson, to help with the session. We secured an Otari 5050 Mk II ¼” two-track reel-to-reel mastering deck with a built-in splicing block on the head cover and a 2500’ reel of Emtec SM 900 ¼” analog tape we ordered from our local pro audio dealer.
Thousands of Otari MX 5050 Mk II two-track recorders were sold in the 70s and 80s around the world. It is a classic design, very durable and relatively portable.
The first thing Jeff did was to clean the heads and tape path of the Otari using 91% isopropyl alcohol and a few regular Q-tip applicators. Ask for the 91% at your local pharmacy as the 70% variety leaves too much water on the heads and tape path. Avoid cleaning the rubber pinch roller with alcohol as it will dry out the rubber and eventually ruin it.
We loaded up the blank tape, and using a direct box and the Otari’s channel-one mic-level input, Spencer recorded a four-bar phrase at the Otari’s slow speed (7.5 IPS). Using the Otari’s edit function, I rocked the reels back and forth to find the attack of the first note Spencer played on the Otari’s playback head. At the end of the four-bar passage, Spencer had continued playing the first few notes of the phrase again, so I marked the attack of the first note’s repeat on what would have been the beginning of the fifth bar with a China marker pencil, the same type used to mark film in the editing process.
With my in and out points marked, I rewound to the first edit, lifted the tape into the Otari’s splicing block, and cut the tape with a brand new razor blade using the angled track in the Otari’s splicing block. Then, I simply reloaded the tape into the guides and pinch roller, hit play (still in “Edit” mode), and the tape played back while spooling off into a neat pile on the floor. At the beginning of the fifth bar, I hit stop, pulled the tape up to the splicing block and cut the “out” point. Then, I simply connected the front and back of the tape segment together with ¼” low-tack splicing tape. There was our first tape loop!
One important tip when creating tape loops: make a directional arrow with the China marker pointing in the direction of tape travel, just after your first splice mark. This will come in handy to ensure that you load the completed tape loop ready to play in the proper direction.
Playing a Loop Setting up your tape loop for playback requires a slight variation on the tape deck’s normal operation. Start by removing both reels of tape from the machine, as the reel motors will spin when you are playing the loop and you don’t want the reels in the way. Plug the machine’s output into your mixing board. In our case, this meant routing it into the Digidesign 96 I/O.
Our four-bar tape loop set up for playback around the "far" tape guide, a mic stand about 18" above the Otari.
If you place the deck in a horizontal position as we did, you can use a mic stand as an extended tape guide. Simply place the tape loop in the tape guides and playback path, then place the loop over a mic stand, and gently slide the mic stand away from the deck until the slack is taken out of the tape loop. Be sure that you do not stretch the tape completely taut! Simply slide the stand back far enough to keep the tape loop from slipping down the stand.
We all held our breath for a second as I poised over the machine’s play button. Click. Out of the speakers came the riff, playing over and over, perfect for dubbing onto a track in the appropriate key – in this case, A-minor. We had spent about an hour hooking everything up and making our first tape loop. While we could have done the same thing in much less time using Pro Tools, the creative options offered by tape loops were now at our fingertips.
One of the first things you can do is to reload the tape loop backwards (with your directional area on the tape pointing OPPOSITE the direction of tape travel). Now, our guitar is playing backwards with each note’s decay eerily building up in volume to that note’s sharply defined attack of the pick plucking the string. Definitely an interesting effect. Another tape loop trick is to use the same loop played at a different speed. The two-speed Otari allows us to play the same loop back at 15 IPS, doubling the speed and kicking the pitch up an octave. Experimenting with this simply requires hitting the stop button, changing the speed to “high” and hitting play. The 5050 also has a vari-speed control, which can be used to subtly alter the speed of loop playback, or if you overdub the loop twice into your multi-track, can be used to create a rich phasing effect between the two loops by varying the second loop’s speed just a fraction.
Other sound sources that make interesting sonic textures include recording cymbal crashes and open chords on acoustic guitars tuned to a specific tuning such as D or A. Even an autoharp makes an interesting sound source to record and loop in either direction. Be sure to let the decay ring out until the level is quite low, as any of these sound sources, when played back in reverse, offer a refreshing effect to use judiciously in your next mix. Your clients will likely be pleasantly surprised at the new textures you can now suggest to make their tracks unique and memorable.
Using Your Studio as an Echo Chamber
The AT 4050 room mic was initially positioned eight feet away from the Tapco S-5 speakers. The speakers were eight feet apart and four feet from the back wall.
The next technique we experimented with was pumping various recorded tracks out into a pair of near-field monitors placed in our studio space and recording that sound with various microphones. Although we use the term “echo chamber,” generally most smaller rooms found in the home lack the cubic volume and enough hard wall surfaces to create truly discrete “echoes,” which are heard by the listener 30 ms or more after the original sound.
We experimented with speaker placement in the room and, more importantly, with mic distance from the speakers to create a bigger sound for the originally recorded tracks. For our tests, we used a snare drum track as well as a hand clap track, both of which were recorded using a close mic set-up. We routed the signal to the TRS ¼” jacks on the microphone panel in the studio and plugged in the Tapco S-5 two-way powered speakers
We set up the snare and positioned our first mic, an Audio-Technica 4050 set to cardioid, about eight feet in front of the speakers. We recorded about a minute of snare hits with the room mic and listened back. The original snare and the re-amped room mic sounded a bit different, but not enough to warrant using it in the mix to our ears. So we moved the AT back another ten feet (which was about as far back as we could go).
The Fat Head ribbon mic pair set up to capture a 360-degree image of the playback in the room.
Next we switched the mic to omni and did a quick listen. It was a bit better but still not enough room sound was coming through. We then added a second 4050 to the first with both mics set to cardioid, on a stereo rail in a spaced pair configuration. We kept the array at the far position and repeated the process, this time picking up some stereo information that made the room seem more three dimensional. All of us remarked that there was now a certain fatness to mix in with the original dry snare. It wasn’t enough of a delay time to give us a discrete echo, but by mixing in a bit of the combination of early- and mid-reflections the stereo mic array picked up, it definitely improved the snare’s overall sound.
We decided to swap out the 4050s for a pair of Cascade Fat Head ribbon mics. The Figure-8 Fat Heads came with a Blumlein-type stereo rail, so we set them up in an over/under pair with the two mic’s pickup patterns oriented in a cloverleaf pattern. We repeated the same test, going directly to a distance of 18 feet from our playback speakers. The Fat Head room mics delivered a smooth, even, slightly buttery richness that enhanced the originally recorded snare drum. This was a sound that would nicely fatten up the original snare when mixed tastefully behind the original track.
Finally, we fired up a click track and recorded two minutes of close-miked hand claps into Pro Tools with the Fat Heads set in the “distant” position. We played back our clap track, once again finding that the re-amplified stereo track, when mixed just behind the original, delivered an awesome, thundering track that incorporated the early and mid-time reflections of our studio space into the sonic palette.
A few tips for creating your own home-made echo chamber: test rooms that have plenty of reflective surfaces, such as a bathroom, garage, kitchen, or tile hallway. Also, try various mic placements, including placing a cardioid mic facing away from your speaker so that it picks up the reflected sound first. If you have an omni mic, you can also try it to see if it picks up the echo chamber’s diverse reflections more accurately.
The Re-Amp is a handy studio device allowing you to playback line level tracks that have been recorded and route them out to a high impedance instrument amplifier in the stuido for further enhancement.
We eventually moved to a stereo pair, as we wanted to simulate what a pair of ears would hear in the room. With the Figure-8 Fat Heads, we got a much denser pallet of direct and indirect sounds due to the two mics Figure-8 pick up patterns, and although there were some phase anomalies as a result, the track played back acceptably when summed to mono, albeit without the same thickness of the stereo image we recorded. Another very handy accessory to use when re-amplifying tracks that have already been recorded is the Re-Amp, an impedance and level-matching accessory that makes sending any line level (+4dB) signal from your workstation to an unbalanced guitar amp in the studio a snap.
In closing, although most of us do the vast majority of our work “inside the computer,” a reconsideration of some of the classic effects techniques of the analog era makes for some interesting and rewarding additions to your arsenal of sound choices. With a little practice and a small investment of time and money, you’ll also develop some new chops that may impress your studio clientele by bringing back some of the old school techniques that helped to make a few of yesterday’s legendary recordings.
