The Loop of the Tiger

Many great pieces of music come to us from a time when popular songs were the ultimate expression of artistic talent rather than mere technological achievements. That’s not to say that good songs are no longer written today; however, in my opinion music is consumed – and produced – nowadays in such a way that more often than not it ends up being ephemeral background noise. Do you remember the last time you sat down to just listen to music?

The Eye of the Tiger by Survivor is one of the songs that has survived the test of time (pun intended), though some will say that the movie this song was written for didn’t age as gracefully, but I digress. Its rhythmic intro is so catchy that even toddlers can perform it distinctly.

I chose The Eye of the Tiger for a demo video of one of the most frequently used Chronotron features: the ability to create loops. Keep reading if you want to go through some details, otherwise skip to the video below and enjoy.

Basic Operation

The Loop In and Loop Out buttons perform the same functions as in CDJ players: press the Loop In button to set the loop start point, and when playback reaches the point where you want to start over, press the Loop Out button to set the end point and begin looping. It’s really that simple.

The Loop button toggles looping on and off. Clear Loop removes both loop points, once you confirm you really want to do so.

Adjusting Loop Points

You can adjust the loop points by dragging them around with the mouse – or the finger, if you have a touchscreen. However, there are cases when you want to change their location more precisely. The Loop pane – depicted below – allows you to manually edit the loop points either by entering their position as text (more on this below) or by increasing or decreasing their location in 25ms steps.

Whenever you make changes and the Play loop end… switch is on, Chronotron will seek closer to the end of the loop so you can hear if the loop juncture sounds right, without waiting for the whole loop to complete. This comes in handy especially when creating long loops.

In the input boxes you can enter any integer number of hours and minutes, appended with “h” and “m” respectively, and/or any number of seconds with or without decimals places, optionally appended with “s”. For example, entering “200.5” is the same as entering “200.5s”, “3m 20.5s” or “3m 20.5”.

By the way, I hear you saying that it would be great if you could also enter a number of beats in there. However, in order for such feature to be useful some more automation will be required (as of this writing Chronotron has a manual beat detector), but it is definitely in my to-do list.

The Demo Video

Here is a short video showing how the Loop feature works in Chronotron. Be warned, though: a song may stick in your head for the rest of the day.

Questions and suggestions are always very welcome.

The Left-Handed Guitar-Playing Animal

I learned only recently that animals can exhibit handedness, or simply put, that some species statistically tend to prefer one side over the other.

In humans, the ratio of left-handed to right-handed individuals is about 1 to 9, which is pretty low. I ignore whether or not the ratio of guitarists to non-guitarists is the same for each handedness group, but still, I kind of suspect that left-handed guitarists are a minority. Suffice to check the price tag of the LH guitar variant as compared to the same “standard” model – which by the way isn’t even labelled as RH. Talk about offer and demand in play!

Seriously, though, I thought it would be a good idea to do something in Chronotron to help musicians learn songs regardless of their handedness. Left-handed pianos not being mainstream yet, this post is mainly for those who play other instruments, though you can of course use Chronotron no matter what instrument you play.

Video Flipping

For us right-handed guitarists, watching a video of a left-handed player and figuring out what she’s doing shouldn’t be more difficult than watching ourselves play in front of a mirror, right? Try that. For whatever reason the mirrored fingering looks really awkward.

In Chronotron, you can apply a mirror effect during video playback by turning on the corresponding switch in the Adjustments pane, which instantly turns Eric Clapton into his left-handed twin.

Note that in the current and earlier releases (version 99) this switch has effect during playback, but not when video is rendered to disk. In the upcoming release the mirroring effect will also work when rendering media.

Left-Handed Guitar and Bass Fretboards

The purpose of the on-screen instrument in Chronotron is twofold: it serves as the visual support for note detection, and it also allows you to play notes – or even chords, if you have a touchscreen – on the go. You can choose between a piano keyboard, a guitar or bass fretboard.

Unsurprisingly, the fretboards are right-handed by default, but with the flip of a switch they become left-handed.

Ideas are Welcome

If you’re reading this you’re probably left-handed. Are there any other valuable features for lefties you can think of? I’m all ears.

Unfrequently Asked Questions

Some of the Chronotron features are rooted in my own usage, others are the result of customer feedback and a few of them are just there for historical reasons. Then, there are those features that every media player must have, which we just take for granted and rarely think about how they actually work.

Examples of the latter are the Balance control and the Graphic Equalizer. Most people are already familiar with balance and equalization so maybe that’s why I seldom, if ever, get any questions about these features. However, while implementing them I did have questions for which I had to figure out the answers. In this post I’m sharing a couple of such questions – and their answers – with you.

The Chronotron Equalizer

What Pan Law to Use for the Balance Control?

In a nutshell, the pan law governs how much you attenuate or amplify the audio signal to compensate for the gradual loss of the left or right channel as you move the balance control in the opposite direction. A lot has been written about pan laws elsewhere so I’m not going to enter into the details.

Chronotron uses a 3dB pan law, which means that it boosts the remaining channel progressively, by up to 3dB, as the fading channel becomes less audible. This keeps the perceived volume reasonably constant during playback and is the same pan law used by many audio equipment.

If you google for articles on pan laws, you may be wondering why I didn’t choose to apply a higher boost, like 4.5dB or 6dB. After all, Chronotron is a media player and not really a mixing app, right?

Well, there are karaoke videos, music lessons and play-along CDs that take advantage of stereo channel separation to let you adjust the level of the backing track vs. the lead instrument just by using the balance control. In Chronotron, balance is applied before the Solo Channel setting, so if you come across this kind of audio material, you can set Solo Channel to MONO to enjoy sound from both speakers while still controlling the mix with the balance control. Handy, isn’t it? In this situation Chronotron behaves like a mixer and the 3dB pan law is still a reasonable tradeoff.

The above example illustrates the well-known fact that the order in which audio controls and effects are applied can sometimes make a big difference, which led me to the following question…

Should the Graphic Equalizer Come Before or After Tempo and Key Manipulation?

I made a case for putting the balance control before any further processing, but what about the equalizer? If we put the equalizer before tempo change and note detection, we cold leverage its effect to prevent some time-stretching artifacts or to improve the accuracy of the detected notes. If we put it after, we could use it to fine-tune the final result for a particular listening environment, for example.

I thought it would be a good idea giving users the choice and that’s what the Pre/Post switch does.

The default position of the switch is Post, which means that equalization occurs – just like in many other media players – at the end of the sound processing chain. In this position the equalizer does its expected job without causing any side effects.

In the Pre position, though, things get more interesting because you can now use the equalizer to make the note detector emphasize a certain frequency range. Also, when using the equalizer as a notch filter, you will notice that its effect will be preserved even after changing pitch.

The choice is yours.

Have Questions? Feel Free to Ask

Ask questions via the Chronotron web site or by posting your comments here. Unfrequently asked ones are welcome!

The Magical Hold Mode

I call the Hold mode one of the magical features of Chronotron. It makes the sound appear to be frozen in time, while allowing you to continue playback – either forward or backward – so slowly that you can distinguish every single note even in the fastest music passages. You can jump to the demo video below if you want to see it in action right away.

To access the Hold mode, click the button. Once in Hold mode, the Audio Scroller takes control of playback and the real fun starts.

The Audio Scroller

The Audio Scroller, or scroller for short, is depicted below. The center of the scroller represents the current playback position, which in this example is close to 02:14.

You can swipe left or right to play forward or backward respectively, as slowly as you want. This works great with a touchscreen, but if you don’t have one you can still use the mouse or the arrow keys. When using the keyboard, first click on the scroller so it gets the keyboard focus.

The red zone indicates that playback won’t be smooth if you happen to go that far back in time. This zone will appear closer to the playback position right after seeking to a new location within the media clip or after having played backward for a while. You can affect the amount of audio and video to be buffered before hitting the red zone via the setting “Maximum reverse playback length” in the Options pane.

In addition to supporting touch, mouse and keyboard input, the Hold mode can be operated with the Surface Dial.

The Surface Dial

According to Microsoft marketing, the Surface Dial is “a completely new way to interact with technology”, but you can just think of it as glorified jog wheel. It looks like this:

Pushing and holding the Dial brings up a radial menu showing the different things the Dial can control, and the Hold mode in Chronotron is one of them. There are other functions that can be controlled with the Dial, but let’s leave those for a separate blog post.

When controlling Hold, clicking the Dial allows to enter or exit Hold mode. Rotating the Dial is equivalent to swiping on the scroller left or right. That’s all there’s to it.

The Demo Video

This demo video shows how the Hold mode can be used together with the polyphonic note detection feature to make music transcription a breeze. Isn’t that magical?

Start using the Hold mode today and post your stories in the Comments section!

Release 99 is Now in the Store

Something Went Wrong with Release 98

Chronotron version 98 was a bit of a sloppy release, to say the least. It turned out that a nasty Microsoft compiler bug caused Chronotron to crash on some systems, rendering the app unusable for some of you.

Crash telemetry data from the Windows Store. The peak occurs at the date when Release 98 was published.

That’s really bad. Compilers bugs are one of the worst things that can happen to an app. They are hard to catch because we developers are programmed (pun intended) to assume that application errors are always our own fault, which most of the time is true.

After figuring out what the problem was, I reverted back to a previous version of Microsoft Visual Studio and submitted a new app build to the Store, which was promptly approved.

I’d like to thank those who were impacted – and those who reported the issue – for their patience.

The good news is that the next planned release – Release 99 – was already feature-complete, so in addition to the urgent bugfix, in the new build there’s also new functionality!

What’s New in Release 99

After my previous blog post on the demise of the Chronotron plug-in, a few of you reported that a key feature of the plug-in had not made it to the app, which is the ability to operate the Tempo and Key sliders simultaneously to perform pure resampling. This is akin to changing speed in a turntable and can be very useful in some scenarios.

Release 99 brings back this feature by the means of a new Speed slider, which can be found in the Tempo and Key pane.

Other improvements in this release are:

  • A couple of switches to control the app layout have been moved to the Options pane under the Appearance section, where they naturally belong. The documentation has been updated accordingly.
  • Polyphonic note detection now works better, especially with the bass guitar.
  • The layout of the Tempo and Key pane has been revamped.

The change log can be found here.

What Was New in Release 98

For those of you who could not fully enjoy Release 98, you will be glad to know that its most welcome feature is the addition of Bass Guitar to the Instrument pane.

As with every release, in Release 98 there were also some layout improvements, bugfixes and a major bug introduced by the compiler, but the latter is now a thing of the past.

Six Lesser-Known Chronotron Tricks

Chronotron is rich in features that allow you to tweak your media clips in all sorts of ways. This post describes some of the app’s lesser-known tricks to keep in your repertoire.

Transpose Without the Chipmunk Effect

When audio material is pitch-scaled by a significant amount, the vocals start to sound unnatural, resulting in something known as the Chipmunk effect.

With Chronotron you can make transposed vocals sound more natural by enabling the Format Preservation option, as shown in the following demo video.

This works best with pure vocal tracks, but as you can see it works surprisingly well with mixed material, too.

The Anti-Karaoke Effect, or Center Channel Isolation

A simple yet effective method for removing vocals from a stereo recording consists on subtracting both channels, taking advantage of the fact that the singer is often mixed right at the center of the stereo image. A lot of apps can do that and Chronotron is no exception.

However, a lesser-known – and neater – trick is to do the opposite, that is, isolating vocals by extracting the audio content that is common to both channels. The video below shows how to use the Solo Channel function to either remove or isolate the center channel when playing stereo material.

The result naturally depends on the way the recording was mixed.

Play Multichannel Audio Files

Remember the DVD-A vs. SACD format war? There used to be a time when multichannel audio was regarded as the future of music, but history took a different turn (unfortunately, some will say).

If you happen to have multichannel WAV or FLAC files, you should be aware that Chronotron can play them! As you can see in the demo video below, channel isolation becomes child’s play.

Fix Audio/Video Synchronization Issues

A video clip having a slightly out-of-sync audio track may not be particularly annoying when watched at normal speed. However, slowing down the clip also causes the audio/video synchronization gap to increase proportionally to the tempo scaling factor. This can become a big deal, for example, when you’re trying to figure out the exact fingering of a fast guitar solo.

As you can see in the below demo, the Video Delay control allows you to perfectly synchronize audio and video so it looks right at any speed.

Use Calculations for Tempo and Key

In the Tempo and Key pane there are input boxes that allow you to enter the desired tempo and key values directly, like 0.5 or 50%.

A good thing to know is that you can also enter formulas there, so for example, if you want to change tempo from 140 BPM to 80 BPM, you could just enter 80/140.

More complicated formulas work too, like 0.5 + 0.2 + 1%, which would result in 71%.

In addition to the above, the Key input box also allows inputting a number of cents by prepending the amount by a sign. A cent is defined as a 100th of a semitone.

As an example, typing +120 results in pitch being scaled by 120 cents up (i.e. 1 semitone and 20 cents up).

Oops? Don’t Panic! Click the Revert Button

Suppose you have been working on a long playlist, setting parameters for each clip and so on, and by accident you open a new media clip that replaces the whole playlist. Oops.

Don’t panic! Clicking the Revert button – the one close to the Undo/Redo buttons – or pressing Ctrl + Shift + Z will get your original playlist back. See how it works in the following demo video.

This function may also come in handy when performing A/B comparisons.

What do You Think?

If there are other Chronotron functions that you would like to see covered in detail, or if you have your own tips and tricks to share, please don’t hesitate to let me know by posting a comment.

Chronotron Speed Changer Becomes Chronotron

A Brief History of a Time-Stretching App

Time-stretching is defined as the process of changing the speed of an audio signal without altering its pitch. One popular use of this effect is to slow down audio material in order to make it easier to transcribe music or speech.

The original Chronotron product was a time-stretching plug-in for Winamp, inspired by my own desire to learn fast metal guitar solos. Released in 1999, it quickly gained popularity among Winamp users and in 2001 it was featured in the CD included with the book MP3 for Dummies, by Andy Rathbone.

Through the years the plug-in evolved to also implement pitch scaling and support for Windows Media Player and DirectX hosts.

Another area of constant improvement has been audio processing quality and performance. The first release relied on a time-domain algorithm, which mainstream hardware of the early 2000’s could handle in real-time. The most recent releases are based on a phase vocoder plus some secret sauce – just like many other competing software – and sound quality is at least on par with the best.

When you’re a plug-in, though, your fate is inexorably linked to the fate of your host application. In the space of a few years’ time, Winamp went from being the de-facto media player to basically zero relevance. Luckily for Chronotron, Windows Media Player has survived for much longer and still refuses to die (just like Microsoft Paint), though it is no longer the default media player in Windows 10, so we can safely say WMP is now legacy software.

Enters Chronotron, the Speed Changer App

When Windows 8.1 was released and the app movement gained traction on Windows, I reused most of the Chronotron plug-in code to develop a standalone player app with built-in time-stretching and pitch shifting controls. The app was called Chronotron Speed Changer.

The Chronotron plug-in was still around as a necessity, as the first releases of the app were lacking in many ways to compete with full-featured players like WMP.

After nearly 100 app updates, Chronotron Speed Changer got many of the WMP features in addition to all the functionality that musicians love: tempo and pitch controls are of course there, but also channel isolation, interactive piano keyboard and guitar/bass fretboards, polyphonic note detection, and more.

Today, aside from some niche – yet legitimate – usage, the necessity to keep the Chronotron plug-in alive is no longer so compelling. This brings us straight to the subject of my post: Chronotron Speed Changer is being renamed to just Chronotron.

The first update will be to the app itself to reflect the new name, which is being pushed to existing users at the moment via the Microsoft Store. As you can see, the web site has been revamped accordingly. You probably came to this post from there.

I also started this blog as a means of better interacting with you, Chronotron users. You will find here tips & tricks, tutorials and information on how to get the most out of the app.

Players Will Play, Plug-ins Will…

If Chronotron Speed Changer became Chronotron, then what will the original Chronotron plug-in become?

That is a great question. The Chronotron plug-in is no longer available for download; however, this doesn’t mean it’s gone forever, so stay tuned. If you feel like it, you can help shaping the future of Chronotron by providing feedback in the Comments section below.