n-Track Frequently Asked Questions

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6. Audio recording & mixing

• How can I transfer a song from a 4 track analog tape multitrack recorder?
  
  I have found an acceptable, though complicated and not perfect, solution to the '4-synchronous-channels-into-one-soundcard'-problem. In the following discussion, I assume access to a 4-track cassette mixer like a Tascam Portastudio or, like my own trusty machine, a Fostex 280. It should be capable of punch-in and out (preferably automatic) and simultaneous recording on all four tracks. I also assume access to n-Track and some other sound editing program capable of time-streching like, for example, Cool Edit. The imperfection lies in the way tape machines operate. 1) It is impossible to have a tape play back at exactly the same speed (i.e. sample-accurate) twice. 2) It is also impossible to avoid variations in the tape speed (wow and flutter) as it plays. This is how I overcome the first of these problems, as the second one is of a more subtle character and also harder to solve. Here goes... 1) Put some marker on all four tracks of the tape a few seconds before the music itself begins. this can be made by connecting a jack-cable to one input and touching the cable for a split-second while recording. Here is where the automatic punch-in/out comes in handy, punching out of recording mode before the music is reached, so the precious track itself isn't accidentially wiped. Record this signal at a sensible level on all four tracks simultaneously. 2) Repeat the procedure after the take ends, taking care not to wipe the fadeout or the next take on the tape. Now, we have two markers on each of four tracks on the tape, with identical distances between them. 3) Record the take, including the new markers, two tracks at a time, with n-track or another program, and then import the tracks afterwards. Don't split the stereo tracks up yet. 4) Zoom all the way in to the beginning of the song, and offset one of the stereo tracks so that the markers align. Then zoom in to the end of the track and note the difference in samples between the markers on the first and second set of tracks. Use the 'select' feature of n-Track to find the exact numbers at the bottom right. 5) Divide this difference with the sample rate (e.g. 44,100 samples per second for CD quality). This gives the lag time between tracks in seconds. Make a note of this number (use a calculator). 6) Using another program, such as Cool Edit, edit one of the stereo tracks. If the marker on the track is after the reference marker, the track is too long and should be shrunk to fit (i.e. subtracted from the total time) by an amount equal to the number of seconds in step 5). If the marker on the tape is before the reference marker, then the track is too short and should be stretched to fit (i.e. added to the total time) by the same amount. Don't preserve the pitch while stretching, or the result will be out of tune. This will take awhile, so this might be a good idea to 'goof off' for a coffee break. 8) Import the result into n-Track, zoom in on the beginning of the song, and adjust the markers to align with each other. Zoom to the end of the song, and check the difference in time between the markers here. This should be considerably smaller than before. The perfection of the synchronisation between tracks is of the same magnitude as the accuracy of the time stretching.The advantage of this method lies primarily in the fact that only one sound card is needed, and the inevitable error is suitably small for most types of music. The backdraw is, that variations in tape travel cannot be compensated in this way, and the process is a bit complicated. Posted by Nils (mailto:nok@post8.tele.dk)
  
  
• If I was recording a song should I record tracks in mono or stereo, what do most people do, and what are the advantages of doing either...
  
  It depends on what instrument you are recording. For most purposes a mono recording is most appropriated as for voice, guitars. If you are recording through a multieffect device, maybe you should record in stereo, as such device will enhance a mono sound outputting it in stereo. Also if you record the single tracks in mono, the final result will be always a stereo song: you can pan each track more in one channel or to the other.
  
  
• Recording near the computer is quite noisy: how can I get rid of the fan(s) noises?
  
  One quick and dirty solution to the problem is to put the computer case in another room, make a small hole in the wall and make the cables pass through this hole.
  There are companies today that sell low noise PCs for audio recording, although they tend to be somewhat pricey.
  Alternatively you can replace your computer stock components with low-noise equivalents.
  The most commond causes of noise are CPU fans, power supply, graphic card fans, hard disk vibrations transmitted to the case etc.
  One quick and dirty solution to the problem is to put the computer case in another room, make a small hole in the wall and make the cables pass through this hole. There are companies today that sell low noise PCs for audio recording, although they tend to be somewhat pricey. Alternatively you can replace your computer stock components with low-noise equivalents. The most commond causes of noise are CPU fans, power supply, graphic card fans, hard disk vibrations transmitted to the case etc. Reviews of low noise computer parts can be found for example at www.silentpcreview.com
  
  
• What microphones do you recommend?
  
  Popular mic models are for example the Shure SM57 (great all-around and works great for electric and acoustic guitars) or the Rode NT series condenser mics. There are hundreds of mics on the market and a big factor is how much you're willing to spend. If you need to do studio recording probably the best choice is a condenser mic, but they typically cost a few hundred if not thousand $. You can find out more about mic prices for example at http://www.sweetwater.com. Also see the mic FAQs at http://www.harmony-central.com/Recording/faqs.html A big leap in the audio quality can usually be obtained by using an external mic preamplifier (for example a small analog studio mixer such as the Mackie 1202) and connecting the preamplifier to the soundcard's line input, as soundcard's built-in preamps are generally of poor quality. Also the recording quality depends heavily on the soundcard. You can find a short list of suggested soundcards in this FAQ.
  
  
• When I record existing tracks get recorded into new tracks
  
  The problem is known as "bleeding" of the audio output back into the newly recorded tracks.
  Make sure you've disabled the audio output as a recording source using the soundcard's mixer or Windows Volume Control (Windows XP, Control Panel/Hardware and sound/Manage Audio Devices (Windows Vista/7) or System Preferences -> Sound (Mac OS X).
  
  Please see the "Getting started/Setting the recording level" online help topic for a step by step tutorial on how to set the recording levels and sources.
  
  
• Why doesn't n-Track allow to use mp3 files instead of wave files for the tracks audio data?
  
  Compressed audio formats, such as mp3, real-audio or wma, are suited for distributing audio files over the internet or in any situation when the size of regular wave files will make their transmission impractical. On the other hand this formats achieve high compression ratios using algorightms that degrade the audio quality, and so they aren't suited for storing audio data in situations where the sound quality must be kept as high as possible. Also an mp3 file requires a sizeable amount of cpu time for the decoding process. If you multiply that for say 10 or 20 tracks, you'll have a fast P-III struggling just for reading the audio files, without any CPU power left for using effects. And since todays entry level PCs come with at least 20 Gb hard disks, the size advantage of mp3 files stored on the hard disk has become irrelevant. For this reasons n-Track Studio doesn’t support compressed file formats for recording or importing tracks, but it only allows conversion from finished wave files (i.e. created after mixing down) to mp3, ogg or wma.
  
  
• How can I reduce noise when I use microphones?
  
  Make sure you turn off or disconnect inputs (such as the line input) to the soundcard/computer that are not being used, which may add extra noise.
  Also make sure that the recording level as set in the soundcard's control panel or in the Windows Sounds control panel is the highest possible without incuring in clipping distortion (which will appear in n-Track as big red flashing signs on top of the recording level meters).
  
  If the recording quality is still not good, the culprit is most likely the computer soundcard/audio interface. Soundcards that come preinstalled on desktop and laptop computers have usually relatively poor recording quality. You may want to install a soundcard specifically designed for audio recording. You can find a short list of recommeded soundcards here.
  
  
• Can I use n-Track to remove a vocals from an mp3 or to separate an audio file into separate tracks?
  
  Mixing audio tracks is a non-reversible process, so you can't “unmix" a song into separate tracks or remove vocal tracks. There are a few 3rd party audio plug-ins (that you can use inside n-Track) which achieve decent results removing/extracting vocals: try searching the internet for ‘vocal remover VST plugin'.
  
  

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