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Jay Graydon. Official Web Site.Uncle Ian's Tech 
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Ian in Liverpool 1997

Ian Eales - the gifted engineer on many of the top Westcoast albums you have in your collection at home (which you didn't even know you had, right?), President of Studio City Sound Corporation, and one of Jay's best friends, shares with us his expertise, offering technical advice on this section.

Read more about Ian on the Wall of V.I.P.'s page where you will find his bio. He has left his mark on music biz for ever and ever by for instance inventing the Vocal Splicer for making life in the studios a lot easier for all musicians involved by cutting down on the time consuming and voice wearing vocal retakes. To begin with I have asked Ian to explain the smart function of this device.

And since Jay says: "When Ian speaks - listen!" I suggest you check out this page thoroughly and you will most likely learn all you ever wanted to know but never dared to ask.

Here is an audio link - Chesky Records - that Ian appreciates. In their own words: "Our philosophy is simple: to create the illusion of live musicians in a real three-dimensional space."



What exactly does the Vocal Splicer do, Ian? Can you tell me the story about it, for instance how it all started, like what made you decide to invent and manufacture such a device?

Vocal Splicer History

In days of old
When Knights were bold...

OOPS, wrong story.

Since the invention of multitrack recording, it has been possible to make several passes of a performance and then make a master take by selecting portions of the many passes and bouncing them into the master track. This is a fairly straight forward exercise for good singers. You simply select the few repairs from the many, cross patch the good track into the master and punch it in. Occasionally, you have to settle for a slightly inferior take, because the defect is impossible to punch around. You can resort to tricks of erasing breaths or copying to a second tape deck and then flying it in. Remember this was long before samplers and harddisk editors. With singers who think Time is a magazine and pitch is where you play cricket or football, it becomes an absolutely tedious chore, taking hours or even days to assemble a passable performance.

Once Jay and I were talking on the phone and he mentioned what a difficult time he was having with a project he was producing. I casually said it should be a simple matter to make a box to cross fade between two performances. Almost before I had finished talking, Jay said "Build it, man!" After a little R&D to determine the best performance values, I built a box that had a fader, two inputs and one output. Jay was ecstatic for about 15 minutes, for being the perfectionist he is, often pitch corrects a take. That meant he had to make a multitude of patches to go from the tape deck to a mult to the Harmoniser and the Vocal Splicer then to the tape deck. This was a major waste of time repeatedly making these patches, so I made a switch box with eight inputs and a loop circuit that could be selected from any of the eight inputs. Now all that had to be done was to patch the eight tape outputs to the switch box, the Harmoniser to the loop circuit and the output of the Vocal Splicer to the input of the master track.

Next I added a second channel, which only splices between channels 2 and 4 for doing stereo crossfades and compiling tracks recorded in stereo. The current version adds a built in TT patch with back shorted inputs to improve noise and cross talk. It is available from Recording Arts in Nashville Tennessee USA. Ask for Carl Tatz (615)321-5479 . You can email me at ieales@ieLogical.com .

It is now possible to audition the tracks and splices by simply selecting the takes on the buttons. Once the map for the master has been made from the eight takes, it can be a simple matter of putting the master track in record and selecting the desired takes with the buttons and crossfading between them.

Once I was engineering a fair singer and the producer and I had completed the master map for a ballad. He got up and said "I'm going home. Don't stay too late putting this together." I said "I'll be done in 5 minutes." He laughed and said "Ha, if you are, I'll buy you a bottle of whiskey." (We both are fans of single malt whiskeys.) He left the control room and went to have a drink in the client lounge. I walked into the lounge exactly 4 minutes and 45 seconds later and told him that The Glenlivet would do fine. He refused to believe I had done it, so we went back in the control room to listen. I played the tape. He still did not believe it, so I soloed the master vocal and played it down from top to bottom. It was perfect. You could not hear a punch and all the breaths were there. He was astounded. At least I shared the whiskey with him.

Once I was doing a movie title song. I thought this singer could sing, and did not bother taking my Vocal Splicer. (I tip my hat to those engineers who did her records.) Needless to say, I was in trouble. At the dinner break, I skipped eating and went and picked up the Vocal Splicer. This was no five minute compilation. We used a Publison for pitch correction and got done about midnight. There is good and bad news in this tale. The bad news is I suffered through recompiling the complete soundtrack because the track done with the Vocal Splicer made the others pale in comparison. The good news is the producer bought two Vocal Splicers. He keeps one as a spare for the rare times it comes back for service.

Another two Splicer story. A producer/engineer had seen a Vocal Splicer in use and bought one for himself. He used it on several projects and said it saved him at least $10,000 per album in studio time. Sometime later, he told the artist he was about to produce that he a had a tool that was going to make doing vocal painless. The artist said "Bull....! A machine like that did not exist and if it did, he would buy two." He bought two.

    Some Vocal Splicer Statistics:

  • Way over 100 million albums sold.

  • Dozens of top 10 hits.

  • Currently 4 hits in the top 10
    (April 1997)

  • $1295 US

Study the Vocal Splicer Application Hints for more details!




Switch Tip

If you have an analogue console, it is good practice to exercise the switches the signal passes through. At least once a month, toggle every switch on the console. More often if you have smokers in the room. If the desk has been sitting for a while and you have a big session coming, it is a good idea to toggle all the switches before the session. This removes the oxide from the contacts and helps to keep them clean. Doing it before the big session will help prevent an intermittent connection from an oxidized switch, in the middle of the perfect take.



Demagnetizing Heads and Tape

Digital Machines - NEVER DO IT!!! Heads stacks on digital machines are not designed to be demagnetized. I don't know the technical reasons why, but if you do it, make sure you have about $15,000 to spare to replace the head stack. (No, I never did it)


Analog Tape Machines Ideally the heads could be demagnetized for every pass, but of course that is impractical. Daily should suffice. The trick is how to do it. Turn ON the tape machine. Yes, ON. Put the machine in INPUT. No harm will come if you don't set input, but the meters and possibly your monitors may object. The reason for input is when power is applied, the power supplies may not come up symmetrically and there is the possibility of a DC current pulse passing through the head. DC and iron make permanent magnets. Magnets erase tape.

The reason no harm comes to the tape machine is that all that happens is the head amplifiers clip. As these are inherently low current amplifiers, there is no danger to the devices in the amplifiers. I have done this on almost all multitrack tape decks made in the last 20 years. The same technique works for cassette decks and open reel recorders.

To actually demagnetize the heads, plug the demagger in at least four feet away from the heads and bring it up slowly to the heads. Move it slowly over the heads and guides, taking care near the heads. Now slowly move it away from the heads and unplug it when it is about four feet away. DO NOT use a demagger with a switch because if the switch is released or fails near the heads, you could have a set of magnetized heads that will be difficult to demag without a much more powerful demagnetizer. They are magnetized by the collapsing field, which could be quite intense depending where in the AC cycle the power stopped. For the really paranoid, you could use a computer UPS to power the demagger, to insure clean, uninterrupted power just in case the power failed while demagging.

One of the myths is how easy it is to demagnetize tape. Tape is very resistant to demagnetizing. Once for my own education, I took a tape and played it, while moving a demagnetizer up to the tape. While this was very uncontrolled and unscientific test, I could detect no appreciable difference until the demagnetizer was within a couple of inches of the tape. There is no need to remove tapes from the control room when demagging, as I have seen done. If tape was that easy to erase, the fields from all the transformers in all the gear in the control room would wipe the tape as you walked in.

If bulk erasing tape, don't just set the tape on the bulk eraser and turn it on, erase the tape and turn it off. If you do this, you will leave a pattern on the tape which can be heard if played. As the erase head does not erase all the tape, but leaves a small gap between the tracks, this noise could possibly remain and form an undesired part of the recording. The correct way is to turn on the bulk eraser, bring the tape up to it, erase and slowly move the reel away. If doing tape wider than 1/4", turn the tape over and repeat. Doing both sides gives an even field all across the tape and a more consistent background noise.

Just to be on the safe side, set your wallet with credit cards down a few feet away from where you will be demagging.



Tech Tip - Monitor S/N Ratio

Many people insist on running the monitor loudspeaker power amps at full level and only using a portion of the output available from the console, i.e. the control room monitor pot never gets past 12pm, even when listening on STUN. While it is true that some power amps in the past used to suffer from input coloration when the input attenuators were turned down, good modern amps usually do not suffer from this problem. Set the input level on the power amp to give a level slightly louder than you would ever listen when the control room monitor pot is fully up on the console and you will achieve maximum signal to noise ratio for the control room monitors. All desks exhibit some noise. Adding 40db or more typical power amp gain to the noise and attenuating the console output needlessly, results in less than optimum signal to noise ratio heard on the monitor loudspeakers. The residual console noise is perceived as a masking signal which degrades the transparency of the perceived mix. The mixer often adds more eq or compression than necessary to get the mix to jump out of the muck.

Consequently on a playback system without the masking noise, the mix sounds overly processed and unpleasant to hear. The same principle applies to Cue systems.

For those of you running a mixture of Pro (+4) and Consumer (-10) equipment like CD and cassette players, the best solution is to bring this external equipment up to +4 level before connection to the desk. Several manufacturers make such devices and they are fairly inexpensive. Those of you handy with soldering irons can make an eight channel device to handle four external players for less than $50. It's well worth the effort.



One Bit DACs and Music

Several CD players today 'feature' 1 bit DACs and oversampling. This is done because a 1 bit DAC has no non linearity's, as do all multi bit DACs. The output of a 1 bit DAC is either 1 or 0 and as such can have no error. These DACs are cheaper to produce. The machines employing them convert the data read from the disk to an oversampled data rate of 64, 128 or other multiple of the 44.1KHz CD sample frequency.

To output the changes between samples, the number of 1's and 0's is altered to give the desired input to the output filters. For example for a 64 times system, if the level did not change between two 44.1 samples, there would be 32 1's and 32 0's in the output stream. If the level goes up, more 1's are output and less 0's. If the level goes down, more 0's and less 1's. A 16 bit system, as CDs are, have a possible 65365 steps from top to bottom. From inspection, it can be seen that with 64 times oversampling, at most 64 steps can be output during one 44.1 sample. If a very steep transient occurs, it is impossible for the 1 bit DAC to output enough energy to faithfully reproduce the transient, and it is distorted. Most of the time this is not a problem, because there is very little energy in the higher frequencies of music. However, it is distorted none the less.

So, what to buy. An 18 or 20 bit Oversampled system would be free of this problem, and all other things being equal, should reproduce the music more faithfully. The extra bits on the 18 or 20 bit DACs reduce the error inherent in multi bit DACs and are discarded to help reduce distortion. The oversampling means the output filters can be more gentle and should result in more faithful reproduction. Just be sure to listen to your favorite kinds of music on several machines before plunking down your cash.



The Early Machine

When recording, often it would be most useful to have an "early machine." Now you may ask what is an early machine. We all know what a delay line is and have used them in creating interesting effects. Well, an early machine is just the opposite of a delay line, it makes things happen before the actually have.

An early machine is most useful to trigger synths or drum machines ahead of when the signal on tape occurs. By triggering the devices early, the delay inherent in the processing of the device is removed and the track keeps a much better feel. The output of the early machine is fed into a delay line. The output of the delay line is fed into the trigger input of the device and the delay is adjusted to align the new signal with the one on tape. Or even make it earlier if the one on tape is too laid back.

An early machine can also be used to move a good, but rushed (early) vocal performance into time. The output of the early machine is fed into a delay line and the delay is adjusted until the vocal is in time with the track. This is much easier than sampling and then trying to fly the sample in by triggering the sampler.

An early machine can also be used to align video to audio playback. Every so often, one gets a video tape with the SMPTE out of sync with the picture. Simply place the early machine on the timecode track of the tape deck, feed the SMPTE to a delay line, the output of the delay line to the synchronizer and adjust the delay line until the picture aligns with the audio.

Once you have an early machine, it is a simple matter to move it into the track slot of the card cage for the required track. Unless you are certain that your tape machine can handle this with the power on, TURN OFF the power. Be sure to mute the control room monitors and any cues, regardless.

To build an early machine, you need a three head analog tape recorder, a set of schematics for it, some wire, an hour and the connector of your choice. Optionally, you can make the early machine on a spare card for the recorder and/or add an output buffer if you have to drive the signal a long way or the playback amplifier is not capable of driving the new load. The ubiquitous 5534/32 can handle this job with aplomb.

A three head tape recorder uses one head for erasing, one for recording and one for playback. When overdubbing, the record head is used for both playback and recording, leaving the playback head unused. Internal switches in the machine connect the output from either the record (SYNC) or playback (REPRO) head to the output electronics. The typical spacing from the record to playback head is 1-1.5 inches (2.5-4cm), and at 30ips, this gives an early signal in the range of 30 to 50ms. At 15ips, these times are double, but one rarely needs anywhere near this much time. Typically, less than 10ms are required to align, so typical delay settings range from 20 to 40ms at 30ips. It is not necessary to know the distance, just adjust the delay line until the new signal aligns to the desired point.

On the schematic find the output of the playback amplifier. This is NOT the output amplifier. Prior to any switches and post any DC blocking capacitor, add a 50ohm resistor in series with the output. Connect the +phase wire to the free end of the resistor and the -phase to a suitable 0v connection close to the output amplifier. A good connection point is across the pull down resistor on the DC blocking cap. Wire the other end to your connector and voila, an early machine. If you have to drive the signal more than 30 feet (10m) or so, it may be advisable to add another buffer or balancing amplifier so as to not load the output of the playback amplifier. As long as the input of the device you are driving is a high impedance, everything should be all right. You can check this by placing the tape deck in playback and monitoring the channel with the early machine. Connect and disconnect the delay device and listen for any degradation to the original signal coming off tape.

WARNING: Over use of the early machine can lead to a severe case of DEJA VU!

Enjoy.


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