ADT-Automatic Double Tracker Simulator

[rockgardenlove]

So I was reading some stuff on the George Martin and the Beatles studio techniques, and it said they used to send many of their guitar tracks through an automatic double tracker.  I assume this was just some kind of delay/chorus something, but it sounds pretty cool, and was wondering if there was a stompbox type thing that might simulate this.  I really like the kind of "semi-warbly" guitar tones that you come across on the later Beatles albums, esp the White Album. 


Thanks!

[MartyMart]

I think that in those day's, it may well have been a tape recorder, guitar sent to the
record head and monitored from the replay head, along with the original, so there's probably
10-15 miliseconds of "delay" between them.
Combined with the "analog/wow and flutter" from tape, it would sound FAB !
I'm sure that's where "ADT" originated .... unless I remember wrongly !

MM.

[rockgardenlove]

^Just read a wikipedia article on it...it is a few ms delay, and then that analog sound...

So for a live effect, the delay is easy.  I've never heard of a really "warbly" kind of effect...its not like a chorus or anything really...

[notchboy]

To start with, I wouldn't take a Wikipedia article as any sort of gospel truth.  A lot of them are "works in progress," to put it kindly.  That Wiki article implies that a singer can do a true double-track that's within a few milliseconds of the timing of the original track, which I find very hard to believe.

Anyway, ADT doesn't use delays of only a few milliseconds -- that's down in the flanging range, and ADT is not flanging or static comb filtering, it's more like somewhere between thick chorusing and a short slapback delay, although there is no "official" definition of what delay range is ADT.  I'd guesstimate 25-75 ms as being the ADT range; 100 ms is starting to get into short echo territory.  I would imagine that they had to run tape machines at fairly high speeds, or use ones that had very little space between the record and playback heads, to get those delays.

Remember the old MXR rack mount Flanger/Doubler?  The Doubler mode is an example of what I think of as an ADT effect.  The old Electro-Harmonix Full Double Tracking effect had a choice of two fixed delays, 50 or 100 ms if I recall correctly.  Adding some modulation makes the double-tracking less fake sounding, but it has to be very, very subtle, or it will just sound out of tune.  You want something on the order of the wow and flutter of a good tape deck, not something that will make you seasick.

btw, the "warbly" sound on Beatles recordings was usually a Leslie, right?

[rockgardenlove]

^Alot of tracks used a leslie...I'm not sure...I'm talking about the kind of subtle stuff like the "While My Guitar Gently Weeps" guitar tone.

Harrison quote on the subject:

"...I was with Eric and I was going into the session and I said, 'We're going to do this song. Come on and play on it.' He said, 'Oh no. I can't do that. Nobody ever plays on Beatles' records.' I said, 'Look, it's my song and I want you to play on it.' So Eric came in and the other guys were as good as gold because he was there. Also, it left me free to do the vocal and play rhythm. Then, we listened to it back and he said, 'Ah, there's a problem, though, it's not Beatley enough.' So, we put it through the ADT (automatic double tracker) to wobble it a bit."

[aziltz]

See i read that same account in Guitar Player and they said it was something about the engineer twisting the "oscillator" on playback.  What that means, i dunno.

[notchboy]

See i read that same account in Guitar Player and they said it was something about the engineer twisting the "oscillator" on playback.  What that means, i dunno.

Oscillator == variable-speed oscillator (VSO) controlling the motor speed on a tape deck.  i.e. it wasn't a Leslie.

[aziltz]

good call.

[rockgardenlove]

^Hehe, thats what it said in wikipedia

Maybe a delay hooked up to an expression pedal then?

[Dave_B]

^Hehe, thats what it said in wikipedia

Maybe a delay hooked up to an expression pedal then?

Seriously doubt that.  Lennon had a tough time with multiple takes, especially if attempting to 'double track' his vocals.  It was easier to use the ADT than to try and get a second take from him that reasonably matched the first. 

I'm not sure if Martin or Emerick have ever detailed how they did it, but we can guess it's just tape delay.  Any manual speed control was probably an attempt to keep the machines from drifting too far apart. 

On that topic, a friend of a friend recently rented Studio 2 for a day (in the last month or so).  I never did ask if they actually recorded anything.     According to the engineers, the piano in Studio 2 is the same one used by the boys.

[bioroids]

ADT is supposed to be "invented" by Abbey Road engineer Ken Townsend (spelling?).

IIRC it is supposed to be a tape delay with the speed varied with an LFO and mixed back with the original signal. Kinda an evolution of the "flanging" effect I suppose.

The aim of this was to avoid having to do several takes to doubletrack the vocals, but they ended up using it in everything. This is the Revolver album mainly, afterwards they just got tired of it, it seems. I don't think they ever used it on the White album and followers, but they did use the tape machine for vibrato (which is essentially the same but without mixing the original signal).

At least this is what I read in many years of searching Beatles recording info...

Luck

Miguel

[rockgardenlove]

Well, Harrison himself says that it was used on the Clapton solo on While My Guitar Gently Weeps...


In any event, is there a box to get that kind of tone?  Its definetly not just straight guitar.  Any tape-warble synth?

[LyleCaldwell]

You can kinda get it from a TC 2290, Korg SDD-3000, Korg DL8000R, and Eventide Eclipse.  The trick is you have to vary the delay time as well as the pitch - most delays have LFOs applied for pitch, but to really do it you have to LFO the delay time.

The Line6 DL4 can do a pretty decent job if you use an expression pedal on the tape echo model's wow.

[rockgardenlove]

Bit too expensive...

Nothing DIY-able?  I just want that very subtle warble.  Would some type of very subtle vibrato get that effect perchance?  Something like an LFO hooked up to both a vibrato and a delay at the same time?

I need that sound!

[Dave_B]

Well, Harrison himself says that it was used on the Clapton solo on While My Guitar Gently Weeps...


In any event, is there a box to get that kind of tone?  Its definetly not just straight guitar.  Any tape-warble synth?

I guess it's time to get the White Album out.  I can't recall any unusual effects on that track.  That means very little, by the way.

For what it's worth, I couldn't find any documentation on it in the Lewison "Chronicles" book.  It mentions it was done on Sept 6, 1968, Clapton used his Les Paul, and gives the impression he didn't spend a lot of time on it, but that's about it. 

[LyleCaldwell]

Dave,

Listen to the piano - it, the vocals, and the rhythm and lead guitars are ADT'd, as are many White Album tracks (Glass Onion and Piggies come to mind).  It's on a lot of post-Revolver tracks, as are Leslie and Fender Tremelo.

I read an interview with Emerick where he described Townsend's ADT as just playing around with the motor speed of a second tape deck with an LFO.  Totally random, and never reproducable.  Townsend also either invented or was one of the very first to use flanging - literally pressing lightly on the flange of the tape reel to slow down the playback or recording speed.  From there it was a short step to ADT.

[rockgardenlove]

^Everything just sounds very slightly off...the backing electric guitar seems really effected up, and the lead has something going too...

It's definetly not a huge in your face type effect.

[SeanCostello]

Pretty sure it is just tape flanging. Same recording played back on 2 tape decks, with the speed of 1 of the tape decks being varied (using the VSO mentioned above to control the tape speed). The tape speed would have to be periodically adjusted, in order to avoid the delay between the 2 units becoming too great, or to avoid through-zero flanging if this is not the desired effect. Since it was a human controlling the tape speed, the pitch change would be more erratic than if driven by an LFO, resulting in a much more interesting sound.

In one of the Beatles books I have, the engineer who applied ADT to Clapton's solo in While My Guitar Gently Weeps talked about how boring it was wiggling the oscillator speed knob for hours...

Sean Costello

[bioroids]

Dave,

Listen to the piano - it, the vocals, and the rhythm and lead guitars are ADT'd, as are many White Album tracks (Glass Onion and Piggies come to mind).  It's on a lot of post-Revolver tracks, as are Leslie and Fender Tremelo.

The effect you mention is very notable, but I think it's not ADT but plain vibrato. It's a very different sound, but is made by the same means of wiggling the speed of a tape machine, either with an LFO or manually. The difference is, for ADT, you need to do it on separate machine so you can mix it with the dry sound.

On the White Album there's a lot of vibrato going on, showcased even in the little track Wild Honey Pie.

A way to get vibrato is to mute the dry signal on most phasers or choruses (there are mods for the Ross phaser I think, to do this). I don't know how close to the tape vibrato can you get with this simple means.

I wouldn't trust too much on the Beatles talking about technical facts  but Harrison did say that Townsend should receive a medal for his invention (back in the Revolver days).

Luck!

Miguel

[RDV]

The Easyvibe on "Vibrato" mode certainly wobbles the sound a bit. At faster speeds it definitely emulates that sound IMO.

YMMV

RDV