Removing Incidental Noise

Incidental noise on a track is always a problem.  In a recent recording session, my acoustic guitarist shifted a couple times on a creaky chair at a particularly inopportune time — right at the end of a track on the final chord.  Here is what it sounded like:

Removing the offending noises using time-based edits (i.e. cutting the piece out, muting the section, or using parametric EQ) to remove or diminish the sound would result in an audible glitch.

Using Sony SpectraLayers, I was able to isolate the sound and remove it without affecting the rest of the track.

Here is a screen capture of the creaks:


And closer detail:


By selecting the offending bits, copying them to a new layer, and reversing the phase of the layer, the sounds are cancelled out of the resulting audio:


Here is the before and after audio:

Friggin’ amazing!

p.s., per request, here is a link to the original wav file, prior to the “fix.

Pitch tuning

I would be surprised if there is a single major release that does not have pitch tuned vocals, even if just a tweak here and there.  Some singers are able to exist only because of pitch tuning and killer videos.

In the  “old days,” before pitch tuning (circa 2000), vocalists had to hit the notes right with their own vocal chords or find a different career.  According to Wikipedia, Auto-Tune was first deployed as an effect on Cher’s 1998 song “Believe.”  Once in the hands of producers and engineers, it rapidly proliferated, and is an essential tool in any pro or serious amateur studio.

The Wikipedia entry is a good read, and talks about musicians protesting tuned vocals.  Frankly, I would be surprised if anyone protesting has not had some tuning done to smooth out a vocal part they missed.

In my opinion, as with much technology, pitch tuning has diminished the art.  A mediocre vocalist can “sing” in perfect pitch.  Style supersedes substance.  But, pitch tuning is deeply and permanently embedded in music culture.  So, like it or not, live with it.

Notwithstanding, I recently gave a presentation on recording techniques, which took me briefly onto the topic of pitch tuning.  I decided to put up a blog post because most non-recording musicians do not understand how it works.  As an example, I provided the following screen capture to visualize a vocal line as recorded by the singer.


(click on the image for a larger view) The column on the far left shows the perfect-pitch notes (e.g. A, A#, B, B# …).  The alternating horizontal bands across the image are the pitches, essentially black and white keys on the piano.  Top to bottom is actually a continuous increment in frequencies that is conveniently grouped by the alternating bands (e.g. the center of middle A=440hz, middle C=261.63Hz).

The blobs in the middle are the notes that the singer sang.  The fatter they are, the louder they are.  Length is the duration of the note.

As you can see, some of the notes sit right in the middle of the band, whereas some straddle between two bands.  The notes between bands are the ones which need to be corrected.  Correcting them is dead simple — just drag the note to its optimal position.  Bazinga – perfect pitch.  Its crazy how easy it is.

Plus, you can shorten or lengthen a note, make it louder or softer, smooth out the modulation or quiver, etc.  Perfect notes.

The software will allow you to take much more creative liberties with the notes, such as copying and stacking to create harmonies, or resetting to extreme positions, such as full octaves.  However, the more extreme you go, the more you introduce residual noise, aka artifacts, which are not desirable.

The technology will improve so as to enable cheap, real-time, zero-latency pitch tuning, i.e. when you sing into the cheap little karaoke box you bought, your pitch will be perfect.  Amazing, yes?

Open tuned chords

Just a quick clarification.  I am not referring to open tunings, in the sense of playing a song in a guitar tuned to open-G, open-D, DADGAD etc.  I am talking about tuning a guitar to an explicit open tuned chord and playing it, if that makes sense.  Let me explain.

A bit of context.  I remember reading an interview with producer Mutt Lange.  He was talking about some recording techniques, and mentioned recording a song where each chord was played on a guitar tuned to that chord.  So, a sequence of chords, say Am – G – F – D7, would be played with the guitar only playing the chord in the sequence for which it was tuned.  Awkward, but intriguing.

His thinking was that open strings sound differently from fretted strings, which is definitely true, and easy to validate.  Playing a song with a lot of quick changes would be a challenge to get it all right, but a portion of a song in which each chord lasts a couple beats over a medium tempo would be easy to do.

So, I decided to give it a try.  I tuned a strat to Am, and capoed on the second fret to give me a Bm (so not totally open, but I didn’t want to tune up to a Bm).  Here is the chord with a bit of vibrato:

And the chord in context, in my song A Delicate Balance:

I like the sound, and intend to use it again.

And for completeness on the topic of open tunings, I really like playing in them.  I regularly play in open-G, open-D, DADGAD, drop-D and double-drop-D.  Definitely something you should try.

Backwards tracks

One of the sounds that I have always been fascinated with is backward tracks.  Backward tracking is a tape technique that has been around since tape was used, but only became popular in the fifties, according to Wikipedia.  Being the Beatles fan that I am, my first experience was on Revolver in 1966.

The technique is simple.  Flip the tape over so the feed reel becomes the take-up reel.   In the digital world, DAWs and audio editing tools allow you to reverse the track.

Reversing a track is easy.  Getting it to work within the context of a song is finicky, but not so bad.  I get a mix together of where I want the reversed track to show up, paste into a new project, reverse that track and then record what will become the reversed track in the mix against that.  It takes some practice, but the track should follow whatever changes are in the composition, the tempo and such.  A bit strange to listen to and record against, but you get used to it.

Here are some examples of reversed tracks.  First is the track played normally, next is the reversed track:

  • from Revolver, the lead break from “I’m Only Sleeping”
  • also from Revolver, the lead break from “Tomorrow Never Knows.”  I think this sounds fabulous.
  • from Sgt Pepper, the inner groove* at the end of the record after Day in a Life.  It is quite a jumble.  It is also sped up.  I slowed it to 74% of the original.
  • The last recording I did, “A Delicate Balance” uses a backward guitar track, panning left and right.  I included the intro to that song.

*additional notes on the inner groove track.

On the original inner groove track, they seem to be saying, “I never could see any other way.”  On the reversed and slowed down track, you can clearly hear the vocal saying “and we’ll all be there to seek your pleasure.”  It sounds like they recorded one word at a time and then put them together to form a sentence.

I think what they did was record the initial track “I never could see any other way”, played it back in reverse, and said, “I think it sounds like they are saying “… and we’ll all be there to seek your pleasure.”  Which they tracked at a slower speed, reversed and played at the normal speed.

One other thing funny about the Sgt Pepper inner groove track is a high pitch just before the inner groove begins playing.  You can see it here:


John thought it would be amusing to include something that only dogs could hear, so they added a 16k sine wave.   The vast majority of humans cannot hear that high.  But on the slowed track, the pitch is now quite audible at about 10k.  You can hear it at the tail end of the reversed track.

Mid-side recording

I was recently wondering about mid-side recording, and decided to try it out.

The technique is to use a figure-8 microphone placed with the “null” side facing the source, while the front and rear sides of the mic face perpendicular left and right to the source.  The recording of the source is done in mono, which means that the resulting mono file essentially has stereo information in it.

The file is then copied and phase reversed.  Placing the two files in a DAW and hard panning them left and right, the resulting stereo output will have a wide mono sound, but the middle is empty because of the phase cancellation between the two identical, phase reversed tracks.

Adding another track, e.g. a vocal track, recorded using a cardioid pattern mic and mixing that in the middle, gives you a complete MS stereo recording.  With an MS decoder applied to the resulting stereo track, you are able to manipulate the stereo soundstage to widen or narrow it, and push the mid-channel up or down.

Its a pretty nifty technique that sounds great.  Here is a recording I did using mid-side technique, of Stephen Stills’ “So Begins the Task”.  There is a lot of presence to the guitar and width across the sound stage.  The vocal sits nicely in the middle surrounded by the guitar.

Here is a discussion on mid-side on Gearslutz.

For additional reference, Sengpiel Audio has a neat page that visualizes the various techniques for mic placement, e.g. ORTF, XY, Blumlein …


Ooo Eee Oo Ah Ah

A recording technique that has long been used for interesting and amusing effect is to change the speed of the playback.  Faster would raise the pitch, slower would lower it.  In some cases, artists slowed the tape speed down during tracking to make instrument parts easier to play or to hit higher notes, and then sped up for the final mix. Other times they would adjust the tape speed during mastering to get a sound they liked more.  The timbre of the notes changes.  Guitars played back at even slightly faster speeds sound chimier.  Vocals at slightly slower speeds have a deeper resonance.

One of my favorite Beatle songs, which coincidentally used this technique, is Rain, where the master was slowed down.  The guitars sound sublime, especially that little guitar break at 2:33.

In thinking about the Beatles use of the varispeed technique, it occurred to me that the backing vocals on Magical Mystery Tour sounded like they were pitched upwards.  And indeed they are.  Here are some parts with the final version followed by the slower playback which would have been used during tracking:

On a tape machine, this was easy to do, as you just needed to flip a switch for preset speeds (typically 30ips, 15ips, 7.5ips and 3.75ips), or change the voltage to the capstan motor (varispeed) for continuous increments.

In the digital world, pitch tuning (Autotune, Melodyne, …) allows you exceptional ability to change notes.  But this does not sound the same to me, and more extreme changes result in artifacts that sound bad.  Changing the playback speed for recording or mastering takes a couple of extra steps.

The “time stretch” function in your DAW or audio editing software serves the same purpose.  In Wavelab, time stretch lets you define how much to stretch the track (%).  It allows you to keep the pitch constant, or to let the pitch change consistent with the change in track length, i.e. longer stretch would lower the pitch.

All that to say, as a little exercise, I took a run at Alvin and the Chipmunks, to see what the real voice behind the little critters actually sounds like.  Here is the amusing result at half-speed, from the original 1958 recording of Witch Doctor that started it all for Alvin:

Finally, the most famous chord of all time …

… the opening chord of A Hard Days Night has been successfully dissected.

In this radio interview with Randy Bachman on CBC’s Guitarology program, RB talks about meeting Giles Martin, son of George Martin, at GM’s private studio at Abbey Road. In the studio, GM has access to digitized copies of all the Beatle’s multitrack source tapes.

After pondering what he would like to hear, RB is provided with solo’d track by track playback of “the chord”.  When it is all put together, HE NAILS IT!  Give it a listen …

Here is the breakdown he describes:

  • Track 1: George on Rickenbacker 12-string  GCFACG
  • Track 2: Paul on Bass playing D
  • Track 3: John on 6-string xxDADG

The notes being picked up are:  A-C-D-F-G

  • From a G perspective: 1-2-4-5-b7
  • From an F perspective: 1-2-3-5-6
  • From a D perspective: 1-b3-4-5-b7
  • From a C perspective: 1-2-4-5-6
  • From an A perspective: 1-b3-4-b6-b7

Closest thing to call it would be a Dm11 or an F6add9.  Whatever you call it, you can’t make the chord sound properly with only one hand (chording) and one guitar.

What a sound. This is TOO COOL!!

Sound engineer humor

One of my favorite sites is, where people, mostly sound engineer types, talk about … gear. Most of the time, the conversations are about experiences with specific pieces of recording equipment or techniques. Some can be offbeat and really amusing, like this one — He Is…the Most Interesting Gear Slut!

Basically, assembling all the collected wisdom, knowledge and opinion about gear, talent and luck, and packaging it as hyperbole. Here are some samples:

  • He mixed the entire Hotel California record in one day on headphones in a room AT Hotel California and then left without checking out
  • Word clocks sync to him
  • He records a whole band perfectly with one mic, in one take, on one track, on tape — and mixes it to surround sound … telepathically
  • He pronounces Moog correctly
  • He’s so forward thinking that the last time he played guitar was tomorrow
  • He can tune a piano and tuna fish
  • He’s won Grammy’s for songs he almost worked on
  • He once wrote a concerto for dog whistle
  • He thought he’d made a mistake once, but he was mistaken
  • He can hear, pan, eq and add effects to the sound of one hand clapping
  • At a lecture, he once uttered, “just do it” and walked off the stage. Nike tried to sue him for using the catch phrase, but ended up being sued themselves by him as he had already developed that exact shoe style for a song intro that required someone running into a house. The album was “Nike Runner” and the title song was “Just Do It”. He did however let Nike keep making the shoe pump that he had invented for the compression effect on that intro. It eliminated sock issues by compressing foot sweat.

… well, *I* think they are really funny. 😎

Just Dropped In …

… to see what condition my condition was in. When Kenny Rogers was cool. I had a flash-back when I was working through lyrics for a new song. This song popped into my head. I looked it up on YouTube and — Poof!! — there it was.

What a song. According to Wikipedia, it was first recorded by Jerry Lee Lewis in 1967, who rejected it. It was a hit for Kenny Rogers and the First Edition in 1968, at the apex of psychedelia in pop culture. Some of the lyrics are worth repeating here:

I woke up this mornin’ with the sundown shinin’ in
I found my mind in a brown paper bag, but then…
I tripped on a cloud and fell eight miles high
I tore my mind on a jagged sky
I just dropped in to see what condition my condition was in

I pushed my soul in a deep dark hole and then I followed it in
I watched myself crawlin’ out as I was a-crawlin’ in
I got up so tight I couldn’t unwind
I saw so much I broke my mind
I just dropped in to see what condition my condition was in

The video is simple but clever. Check it out.

The video is on YouTube Channel WABCRADIO77, whose mission is to present classic “oldies” music the way it was meant to be – in it’s original form exactly as it sounded when the song was a hit on the radio. All the songs are played from original vinyl 45 RPM records.

Very cool.

Full-spectrum ears, great gear & a passion for audio