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  • With version 5.0.9, the iOS version of the Sing! app gains a new video filter option: the so-called Blemish filter. It’s a live video filter, which detects smooth surfaces like your skin and adds a blur filter to make them appear even more smooth. 
    The effect can be turned on and off before, during or after a video recording. It works in combination with the existing filters like Selfie, Vintage and so on. 

    without (left) and with Blemish filter (right)
    Have you used the new option yet? How do you like it?
    We already published an article about uploading songs to Smule. But what if you don’t have karaoke versions of your favourite songs and you can’t record them yourself playing an instrument? Then you might try to remove the vocals from an original track. Here is an article about how this can be done. 
    But let’s be clear about it in advance: a perfect karaoke track is one that never had vocals to begin with. Unfortunately, there is no reliable way to remove vocals from any song. You can mute a voice track in the studio, but once the final recording is produced, the voice is mixed in with all the other instruments and hard to remove. 
    There are two basic principles to try it anyway: Isolating the voice through its frequency range and isolating the voice through its placement in the stereo panorama.
    Identifying and removing the frequencies of a voice is easy to do with an audio equalizer, but the problem is: the frequencies the singer uses, are usually also used by the instruments, so you would remove them as well. So for most songs, that doesn’t get us sufficient results. It might work to just lower the volume of the voice though. 

    If you have an audio editor with a spectral pitch display (see above) you could also use it to identify the individual notes of the singer and then delete them manually. But the process is quite cumbersome. So we rather focus on the typical way to create karaoke songs from original songs: the center cancellation method. 
    Removing vocals through center cancellation
    This method is based on the fact, that the voice and the instruments are usually distributed in a certain way across the stereo panorama, i.e. the left and right channel. The lead vocals are recorded in mono and almost always placed exactly in the center, while other instruments are either recorded in stereo or they are mono and placed somewhere on the left or right. If all that is the case, we can – in theory – easily isolate the lead vocals by just removing what is exactly in the center. This can be done in any audio editor, free or professional. You take the original track, split it in two tracks if necessary, and then reverse the phase of one track. As a result, what is played in the center will be played on both channels and through the phase change both channels will cancel each other out regarding the equal (center) parts. What was exactly in the center, is now removed. Here is a video tutorial for this technique using the free audio editor Audacity, which is available for Windows, Mac OS and Linux. But you can use this technique in almost any other audio editor and recording app as well. 
    But don’t be surprised if the results of this technique are usually rather disappointing. There are two main reasons for that:
    The voice usually has stereo reverb (or other stereo effects) added to it. Those effects act across the entire stereo panorama and are therefore not removed through the center cancellation technique. As an active Smule user you have probably heard lots of background tracks like that in the Smule community songbook.  Other instruments are usually also playing in the center and they are removed as well. So the background track will often sound rather flat and tinny.  Better results can be achieved if you use professional audio editors. They will also use the center cancellation technique, but they provide settings for it as stock option or through third-party plugins. So depending on the song, you have detailed control over the frequencies that get removed and the amount of space you remove from the stereo panorama. As a result, you can remove as much as necessary from the vocals, but keep as much as possible from the instruments. 

    Plenty of options in the “Center Channel Extractor” effect in Adobe Audition
    Whether or not the center cancellation technique works depends on the mastering of the specific song. Even for songs on the same album, it might work well for one track, but not at all for another. In my experience, the best results are achieved with uptempo pop and rock songs. The lead vocals have usually very little effects added and the instruments are distributed evenly across the stereo panorama. An acoustic song with a guitar and a voice on the other hand might not work at all. The instrument and the voice will usually share the same space in the stereo panorama and the same frequencies, so you can’t remove one without also muting the other. 
    But if you are missing a certain song in Smule, give this technique a try! With apps like Audacity you can even try it for free. 
    And feel free to let me know what your experiences with voice removal are! Which software do you use? What do you like about it? What are your tips and tricks?
    Your favourite song isn’t in the Sing! app yet? Then maybe add it yourself! It’s pretty easy! All you need a desktop computer and a karaoke version of your song. I don’t want to recommend any copyright violations, so for this article we assume that you created the karaoke version yourself, e.g. by recording yourself playing an instrument or by arranging a MIDI song in an app like GarageBand. So you should now have a lossless audio file of your song as .wav or .aiff for example. Now let’s go through the process of preparing the song and uploading it to Smule. 
    Preparing the Audio File
    To upload a song to the Smule community songbook you need an .mp3 or .m4a file which is smaller than 20 megabytes and shorter than 10 minutes. So you can usually upload your live recording or arrangement straight away, but it’s often useful to optimize it first with an audio editor. A popular choice is Audacity, since its free and available for all major operating systems. 
    There are a few things we want to check and optimize now. 
    1. Normalize the Song
    As you might have noticed, songs in the community songbook can have very different volume levels. In an audio editor you can manually change the volume, but you should at least normalize the song. This brings the average or peak amplitude to a target level (the “norm”). In Audacity, just pick the Normalize filter from the effects menu to normalize the entire song. 

    Guitar recording before (left) and after normalization (right)
    2. Remove Silence
    Don’t you hate it when community songs start and/or end with several seconds of silence? It’s especially annoying with video OCs. So make sure you remove that silence before uploading a song to the songbook!
    In Audacity just zoom in to the beginning and end of the song, select the area where no music is playing and hit backspace to delete the silent parts.  
    3. Fade in and Fade out
    If the volume jumps abruptly at the beginning or end of the song, it won’t sound very good. Even just a little bit background noise coming from your microphone can create this unwanted effect. To remove this problem, you can add a fade in effect at the beginning of the song and a fade out at the end. Select a part of the beginning or end and select “fade in” or “fade out” from the effect menu. 

    See the volume jump at the end where the music stops abruptly? We should add a fade out effect to the selected part to improve the recording. 
    When the song is ready, we export it as .mp3 or .m4a file. Feel free to pick a high bitrate for better quality, since a small file size is not important for the use of a song in the Smule app. 
    Song Upload to Smule
    Now open http://www.smule.com/s/upload/ in a desktop browser and pick “Songbook” to create a new karaoke song available to everyone. 

    Select the .mp3 or .m4a file you just created. 

    Add the song title, artist, a cover image and tags. You could skip the last part where the lyrics are added, but it is highly recommended that you add them. 

    So write down the lyrics or just copy and paste them from another site. Make sure the line-breaks make sense, so the singers can easily follow the lyrics. Assigning the lines to singer 1 and 2 is optional, but also highly recommended. To assign a part to a singer just click the button next to the line of the song. 
    If the original song is divided among two singers, e.g. there is a male and female part of a musical song, then replicate this separation. For most songs it is totally up to you how you divide the parts. In general, you want to try to keep a good balance. Don’t let one singer sing alone for too long—but also don’t switch between the singers too fast or too often. And don’t assign the lines randomly. Make sure there is a pattern to it, e.g. switch every second or fourth line of the verses and then let them sing the chorus together. Often the pattern gets reversed after a while (e.g. after the first chorus), so every singer gets a chance to sing all melody parts of the song. 

    After you have assigned the parts, you need to set the timing of each line. For this the song is played for you in the browser. You only need to hit the space bar, once the next line (the one below the speaker symbol) is supposed to be sung. You continue this process throughout the song for each line. It’s simple, but you can easily make mistakes if you don’t hear the original voice to guide you. If you made a mistake, you can jump back to specific lines or just start over. But please don’t upload a song with mistakes in the timing of the lyrics. Tens of thousands of people might want to sing your song and they will all struggle, just because you wanted to save 3 minutes and didn’t restart the timing after a mistake. 
    When you have set the timing for every line, you can play the song again to make sure everything is correct. It helps to sing the song aloud as you would sing it in the app. When you save then song now it gets published immediately in the app and everyone can create solos and collabs. Be aware that there is no delete option at the moment. So make sure you are really happy with the result before saving/publishing. 
    If you have additional questions about song uploads, feel free to ask!
    The rumor about Apple removing the headphone port from the iPhone 7 has sparked a lot of discussions—even months before the official release of the device. Users of Sing! Karaoke app were also worried all their Smule gear (microphones, headsets, earphones or adapters like the iRig PRE) might stop working. Now that the iPhone 7 was officially released, we can take a look at what works and what doesn’t. 

    The Good News: Adapter Included
    Apple’s so-called EarBuds now come with a lightning cable (see image above) since the headphone socket is indeed gone. But you can still connect all your existing devices you plugged into previous iPhones and iPads—and you don’t even have to buy an additional adapter, since it is already included with the iPhone 7. 


    If you plug this adapter into the lightning port of the iPhone 7 the phone will work like any previous iPhone with a headphone jack. The adaptor provides the same analog input and output and all your old gear will continue to work with the iPhone 7. Hurray!
    The Bad News: One Socket Less. 
    With previous iPhones and iPads you might have used both sockets at the same time. For example, to use a headset with the analog audio socket and to charge your phone at the same time using the lightning socket. Or you might have used an external microphone like the Apogee MiC with the lightning connector and headphones with the analog audio socket. Well, you can’t do that anymore. At least not easily. 
    The lightning connector is now the only socket and because of the way this connection works, there aren’t even true hubs available to connect multiple devices at once. Apple’s recommendation is to go wireless. With the iPhone 7 they are also introducing a (rather pricy) wireless headset called AirPods, but there also many wireless headsets available from other vendors. 

    A solution to connect one adaptor or lighting device (like a microphone or headphone) and still charge the device at the same time comes from Belkin and costs around $40. It’s called Lightning Audio + Charge RockStar. With it, you can continue to use your older gear meant for the 3.5 mm audio socket and still charge your device at the same time—but you need to plug in two adaptors at the same time and so it gets pretty messy. 
    Another option for your desk or nightstand might be the Apple dock. You can charge the phone by connecting the dock through a lightning cable and there is a headphone socket to connect regular analog headsets or earphones. I read that the headphone socket on the dock would be a combined headphone/mic input socket like on the older iPhones. In that you could also use it to sing with a headset or adaptors like the iRig PRE—but I haven’t seen any official confirmation about this from Apple. 

    Another way to provide power to an iOS device and/or to an external device like a microphone is through Apple’s Lightning to USB 3 Camera adaptor. Official support is only guaranteed for iPads, but people have also successfully used it with iPhones.

    With this adaptor you can connect bus-powered USB devices like microphones to your iPad and the necessary power is provided through an additional lightning cable connected to a wall socket. So this might an option for you, if you have an iPad and one of the many iOS-compatible microphones (e.g. from Blue, Apogee, IK Mutlimedia) which come with USB and lightning cables. The microphone has to be compatible with the Sing! App of course and the power adaptor has to provide enough wattage. While this solution won’t help you to connect multiple lightning devices (like a microphone + cable headphones), it can help to provide continuous power to use the Sing! app longer. Here is a YouTube review with some more information: 
    Singing with people from all over the world on the Sing! App is great, but if you want to really spice up your collabs try adding some harmonies. Experienced singers will often just create them by ear. Over time you just get a feeling for scales and chords and you learn to create melody variations and harmonies while singing. But what if you want to learn to sing harmonies from scratch? Just follow our two-part article and we will teach how to do it! 
    Harmonizing just means to add additional notes to an existing note. But which notes? There are so many choices! Think of a piano for example—it can play 88 notes. Or can it? In fact, it just repeats a block of 12 semitones played at different frequencies. But since a song in Western music is written in a certain key, we don’t even need all 12 semitones. In a key we just need 7 notes. Using C major as an example we get the well-known note progression: C, D, E, F, G, A, B. (That’s all the white keys on the piano by the way.)

    If we go one note higher, we have closed the circle and end up at the octave. The frequency of the upper C will be exactly double the one of the lower C and as a result their waveforms match up in a way that we perceive them as the same note, even though the frequencies are different. And that is why we can sing any song in different heights as long as we hit the right notes within the different frequency ranges. 
    But now back to finding the harmony notes: If we omit the one note the melody is using at a given time, we narrowed down the choices for a harmony note to just 6 possible options within the given key. While all 6 options might be used in more complex arrangements, some notes do work better than the others, especially for beginners. The most typical and basic harmonies are parallel thirds and fifths. So the whole movement of the melody is repeated, but shifted 3 or 5 notes above the melody. So in the key the song is using, count up from any melody note as first note (let’s say C), skip the next one (D) and then sing the 3rd note (E) as harmony note. That’s it! If you manage to sing this note and you can resist the urge to also sing the base note of the melody the duet partner is singing, you managed to sing harmonies.  
    Thirds as harmonies are especially popular. You can hear them in pop arrangement all the time—or in musicals for example. Even if you haven’t learned to read musical notation: Take a look at this excerpt from a song from the Lion King. Both voices (male and female) start out with individual parts in the song and then both voices sing a finale together with harmonies. This part uses thirds and ends in a more open fifth. Very simple, but very effective! 

    Expert tip: As we have learned, the octave we are in doesn’t matter much in regards to the perceived note. So instead of going up 3 or 5 notes in the key, we can also go lower and sing the equivalent notes an octave below. In that case, going down 6 equals going up 3, and going down 4 equals going up 5. So if the melody is already so high that you can’t go further up, sing the thirds and fifths an octave down.  Now that we have understood the basics, let’s try it out! Here is a simple melody in C major created for the purpose of this article. Click play and get familiar with the melody which is played first. After that comes the harmony part alone. It is based on thirds. Listen carefully! It’s an advantage of thirds that the interval to the base notes is rather small. But it can be a disadvantage as well if you struggle to keep that interval and fall back to the melody line. In the third round the melody and the harmony are played together.    

    Now let’s practice singing the harmony notes on top of the melody. Sing along with the following video. To make it easier for beginners, we start by singing only the harmony (right side of the video). Continue singing it with me when the melody joins in (left side of the video). Then I will stop singing the harmony and you have to carry it on alone until the end. Feel free to repeat the exercise as often as necessary. (Or join the OC on Smule as long as it is open.)

    If you managed our beginner’s exercise, try practicing this technique with other songs on Smule. The rewind function (on the iOS version) makes it easy to practice a part until you get it right. If you can’t manage to sing the harmony part, because the melody in the OC is too dominant and distracting, start a test OC yourself and practice the harmony line without a melody.  
    If you can play an instrument, you can find or look up the original melody and then shift the notes to thirds and play them to memorize the harmonies. If you don’t play an instrument, try to find the first note of the melody, sing it and move up the scale to find the first harmony note. Then try singing the shifted melody without background music first. If you feel comfortable singing it, try it with the music and the melody. 
    The more you practice this, the easier it will get to hit the thirds or even fifths without even having to listen to them first played by an instrument or sung by someone. 
    While parallel harmonies on thirds and fifths are usually pleasing to the ear and work with many songs from many genres, they aren’t always the best choice. There is a certain tonality to these harmonies which might not always be desirable and since you are just replicating the melody, there isn’t much creativity and tension in these harmonies. So in the follow-up article we will look at options for more interesting and creative harmonies. Sign up on Sing Salon so you don’t miss it!
    If you start out with the Sing! App on your phone or tablet, you probably use a simple headset like the one that came with the device. And that is fine! The Apple EarBuds for example are pretty good for what they cost. But if you are looking for better options you will find that the professional microphones used on stage or in studios are meant to be plugged into a professional mixer, not a phone or tablet. But with a little device, you can use any professional mic in the Sing! app. There are two problems to overcome:
    Audio cable jacks
    Professional microphones use the XLR connector standard with three pins. Today’s phones and tablets use a 3.5-mm 4-conductor audio jack for analog audio input (microphone) and output (headphones). It is basically a tweaked headphone socket with an additional connection for the microphone to save the room for a dedicated microphone input socket. As a result, you can plug any headphone with a 3.5-mm jack into your phone, but not any microphone. The microphone cable needs to be specifically made to work with these 4-conductor phone sockets. So even microphones with a 3.5-mm phone connector, which might work for your computer or digital camera, won’t work with your phone or tablet without an adaptor—even though the jack fits in the socket. And XLR microphones aren’t meant to be plugged into phone ports at all. 

    Left: XLR jack Middle: standard phone connector jack with 3 conductors for left, right, ground (“TRS”—Tip, Ring, Sleeve) Right: Typical smartphone connector jack with 4 conductors for left, right, ground and microphone/control signals (“TRRS”—Tip, Ring, Ring, Sleeve) Phantom Power
    Professional microphones, especially the ones used in studios, are often condenser microphones. They require a permanent power source to work. If you just plug a condenser mic in a regular mic input, you won’t hear anything at all. To make a condenser mic work with Smule, you not only need an XLR to phone connector adaptor, you also need to provide the necessary phantom power. But luckily there are several devices available to achieve this and they aren’t even that expensive. 

    A common choice is the iRig PRE, which I use myself. You can plug in any XLR microphone including condenser mics. The phantom power is provided by a battery which lasts for about 10 hours (or 30 for dynamic microphones). There is a gain control knob on the side of the iRigPRE. You need to play around with it a little bit to find the perfect setting, so the mic input signal in Smule is neither too high nor too low. There is an additional headphone socket on the device, so you can still hear the audio signal from your phone or tablet. However, the sound quality is not as good as when you plug the headphones directly into your phone or tablet and the buttons of the Apple EarBuds also stop working. 
    The iRigPRE output is an analog audio signal, so you can be sure it works with any app that supports the regular mic input port (so basically all of them). There is also the much more expensive iRig Pro I/O, which has a digital output and connects to your device through a lightning or USB cable. This should provide a better audio quality with less noise, but I haven’t tested it myself and can’t say if it is compatible with the Sing! app. 
    Similar to the iRigPRE, both in price and functionality is the TASCAM iXZ. The advantage of it is that the input socket does not only support XLR jacks, but also 6.35-mm jacks for guitar/line input. As with the iRigPRE you can be sure this works with Smule and any iOS device with a 3.5-mm headphone socket. 

    The discussion section below this article has been closed. If you have more questions regarding this topic, please use the forum. The many questions can be structured and answered better there. 
    Has this ever happened to you: You join a video OC and everything works fine, right until that tricky part at the end which you then mess up. So you start over only to screw it up once more. Frustrating, right? So here is what I usually do to avoid this problem and save some time. 
    Instead of going straight for the video join, do an audio join first. You are probably aware that you have access to a rewind function here. The markers are set automatically and as a result you might not end up where you want. The jumps might be too small or too big. So use the flag symbol instead to set a custom marker. Once you have set such a marker, the automatic markers become inactive and you can always jump to that one position you have set yourself—until you set a new custom marker later in the song. 

    With these custom markers you can easily practice specific parts of the song. Whenever it is your turn, set a custom marker right in front of that section. If you manage to sing the part without problems, just continue. If you struggled, hit the rewind button and try that section until it works perfectly. With this method you save a lot of time, since you only practice the tricky parts over and over again, without the need to go through the entire song. Once you have managed the audio-only practice, abort the audio join and start the video join instead.