How to make practice CDs for choral parts

Using midi files for parts                            Open this page as PDF to save and print

Many choirs have wished at sometime they had CDs for members to learn parts from.

These can be made from midi files. Unfortunately, midi cannot be made easily, if at all, from choral performances. A midi file is only a set of instructions to operate an instrument: on, off, pitch, tempo…  a bit like a player piano roll. It is actually a text file and carries no wave form information itself so it can be applied as a controller for a wide range of instruments and sound generators.

For choirs, midi (.mid) is often to be found indirectly in the form of Noteworthy Composer  (.nwc) files or can be exported from them or other notation programs. Not all programs do it as reliably as Noteworthy which at only $US49 is excellent value. It has cost me only $US15 for updates over a period of 17 years.

Noteworthy Composer

Here is a file in Noteworthy Composer –

Noteworthy SATB example

Noteworthy  Composer SATB example.                                                      (Click for larger view.)

Separating out parts

This extract is from our Carols for Christmas, but CPDL and The Cyber Hymnal among others have a vast collection in NWC format which can be opened in Noteworthy and re-arranged as required.  A feature of Noteworthy is the ease of entering notation and it can also be separated out, not always without work, but readily. On original entry there is a layering method available so SATB parts and others can be entered on separate staves and printed conventionally as above. The highlighting of the bass part above shows the stave has hidden layers.

nwc-expanded -staves

NWC file with layers shown for SATB.                                                        (Click for larger view.)

Notation can be entered, pasted or imported in the usual way on each stave and tail positions set later for the whole stave with one click.

If the work is the usual form, or even worse mixed up parts on the one stave, it is fairly easy to separate them out. For the treble stave with SA mixed, add another stave and copy the whole of the original to it. The soprano part can then have the alto notes removed and any consequential changes made. Similarly, do this removal across all the remaining parts. The lyrics, if any, can be ignored because they do not sound. Note spacing likewise is irrelevant.

Next a conductor track needs to be added. This will set tempi for the whole work. If there is likely to be confusion remove tempi from the parts at this stage and copy and paste them to the conductor stave. It is also possible to set precisely any rits, accel. and fermata.

Critical repeats, where tempi or dynamic changes occur, may need to be allowed for by cutting and pasting those repeats for all parts. If this is not done the resulting midi export file without effective repeats may miss significant conductor markings. This is the time to put these in the score if you want your choir to learn them at home.

nwc-conductor stave

Conductor stave added by duplicating soprano stave.  This can be muted for playback.                                                                                                                                                 (Click to enlarge.)


Midi files have no voice of their own so we need to assign one to each vocal or instrumental accompaniment staff. These work well:

  • Soprano soloist  -Oboe
  • Soprano   – Clarinet
  • 2nd soprano  -Soprano sax
  • Alto  -English horn (Cor Anglais)
  • Tenor  -French Horn
  • 2nd tenor Tenor sax
  • Bass  -Bassoon

Ding Dong Merrily on High          Download samples – zipped mp3s, nwc & midi  (5Mb)


A real wind band! Choral oohs and aahs are also available but are hard to distinguish in parts. It is possible to add a grand piano, harpsichord, organ or other instruments in the ensemble. Ultimately the individual choral voice will be highlighted in the mix so the presence of the other voices and instruments in the background is helpful for cueing and placement. The dynamics should appear in the parts but the overall levels for each part will be set in the following SynthFont stage. Instrumentation can be done in SynthFont but it has proved simpler in Noteworthy.

Exporting midi file from Noteworthy Composer

Exporting midi file from Noteworthy Composer.                                             (Click to enlarge.)

SynthFont to convert midi to wave files

Done! (with Noteworthy.)  We now have a midi (.mid) file but it is nothing more than mere performance instructions for a machine. When opened in Synthfont, the instruments assigned in the midi file are given life. A soundfont is collection of samples for an instrument throughout its range and there is a general midi (gm) numbering standard for these.Gm soundfounts can be used interchangeably. Synthfont comes with a good soundfont so you are unlikely to want to change it. It does not need special sound cards as it can be used in memory. SynthFont is doing the real work of picking out the sample notes required and assembling a virtual orchestra. Get it here.

Midi file opened in Synthfont

Midi file (ex Noteworthy) opened in Synthfont.                                               (Click to enlarge.)

In the enlarged image it is easy see that the conductor part, now assigned to a clarinet along with the soprano part from which it was copied, has not been muted yet. Most what is on the screen is not needed, only what is boxed.

Using SynthFont

Using SynthFont.                                                                                                      (Click to enlarge.)

Wave file production cycle

  1. Check that conductor track is muted then follow the blue numbers on the illustration above. Select all the parts, other than the voice for which the practice CD is being made, so they can have their volume reduced. When highlighted as a group the slider will set all those in the group to the same level. A level about 0.30 for the background works well. Leave the voice for output at 1.00 to start. This can be increased in the next step.
  2. Playback to speakers and adjust the levels live for the output voice if necessary.
  3. When this is satisfactory play the arrangement to a file. This will be an audio (.wav) file.
  4. Repeat until done.

File management

File management is important at this stage as the whole process must be repeated, from the initial opening of the exported midi file, for each voice and each movement. A suggested naming form is S_nn_movement_name.wav. For SATB you will finish up with at least 4 files for each movement. If you have split voices these should have their own CD too and something like S2_nn_movement_name.wav will be needed.

The individual voice wave files output need to have the same names across the parts for the movements and all numbering have leading zeros eg. 03, 04.. ; sorting is important. For the split voices one simple trick is to create a separate folder for each of them, copy their output files to them and later assemble their CD by copying into the folder the other movements which they are to sing where the voices are not split. There should ultimately be a folder for each voice type plus one for each of the splits. Each folder should contain all the wave files for that voice type in order by movement so the whole CD for each can be burnt when passed to the burning stage that follows. Any files out of order will be burnt to play out of order. Make initial test CDs to check this then burn away.

Burning to CD

Finally! Now with a heap of wave files made we are ready to burn them. Many of you will have a suitable program but be warned this stage can be frustrating as you discover the foibles of your resident burner. Apart from cranky software you may have to deal with the physical device has to actually burn microscopic holes in the CD disk dye layer and it can get hot and possibly overheated with extended work. Burning a batch of,say,10 only at a time with cooling rests is likely to prolong the life of your DVD/ drive.

Another burning tip is to not use the highest speed the drive is rated at and the job may even complete faster! The media are not all of even quality and the slower speed may allow burning to succeed at the first write attempt.

The right CDs
The CD disks required are labelled CD -R. Don’t attempt this work with +R even should they be a lot cheaper; the control information on them prevents them being used for originating work.

Don’t buy the cheapest disk you can find unless you have already proved their quality. Disks have standards and compliance will be on the label: look for ansi standard, these are an acceptable level and are frequently no dearer than ungraded disks.


If your operating system doesn’t have a built in burner to make audio CD’s you will need to install one. These can all be quirky. It is not uncommon to find a burning program simply refusing to co-operate without explanation. Some of them take on the role of rights-management-controller and I have simply had to bypass them and use something else. I used to resort to Linux which didn’t care about such things but as we have to provide for Windows users a good choice is ImgBurn available here This is free to use and devoid of in-built advertising which has become a pain.

ImgBurn Creating cue file

ImgBurn Creating CUE file.                                                                                     (Click to enlarge.)

There are two parts to burning an audio CD which can be played in any CD player: one is making the CUE file, the second is to burn the CUE file.

ImgBurn Selecting file to add to CUE sheet for burning

ImgBurn Selecting file to add to CUE sheet for burning                             (Click to enlarge.)

The background window opens up immediately on choosing to create a CUE sheet. Click the button marked in red to open the voice part folder, label it appropriately and set that as the CUE sheet to provide instructions for the burning. You are now making a music CD not a computer data disk.

Final step

ImgBurn The CUE sheet being burnt to a CD

ImgBurn The CUE sheet being burnt to a CD.                                         (Click to enlarge view.)

This final step requires selecting ‘Write’ under ‘Mode’. It will look for the CUE sheet you have created and proceed to burn as many copies as entered. You have to repeat this for all the voices and you can come back at any time and re-use the CUE sheet for each voice to make fresh CDs.

Using MP3 files

These can be used in a CUE sheet along with wave files. Files of 192K are hard to tell apart from originals. Audacity  (availble here)  can produce these if you need them. There is no need with MP3s for the midi to wave conversion setout above.


S.D.G. Kev.

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