Roland MRM 500
Midi File Converter
Roland's MRM500 software offers unprecedented file compatibility between software sequencers and their MC-series sequencers. Vic Lennard asks if it's too good to be true.
FOR THOSE OF you not already familiar with it, the Standard MIDI File format provides a method of saving songs via the disk drive on one sequencer, and loading into another. If the sequencers are software running on the same computer, there's no problem with disk format. However, very few of the hardware sequencers use a compatible disk format and so loading a MIDI File would be impossible.
While Roland's MC-series of sequencers are renowned for their reliability and sturdiness, there's no substitute for the power and level of visible information available when editing on a computer. The inclusion of MIDI File compatibility for these sequencers, therefore, would make them even more useful to the editing musician - and that's precisely what the MC-series' MRM500 optional software provides.
MRM500 can be used in any of the MC series - MC300/500 and the new MC50 (reviewed MT, Jan '91) and facilitates the use of the Super MRC software. You are supplied with a System Generator disk, from which you create an MRM system disk; this contains the software program for MIDI File conversion which the MC sequencer loads each time you need to do a conversion. The idea of using different "system disks" is a good one because a MIDI device can be continuously updated without the need for sending it away to have a new ROM fitted.
There are four modes in which the MRM software works. Mode 4 lets you initialise (or format) a disk to IBM PC format (it is also compatible with the Atari ST range of computers). If you're using an Apple Macintosh (you lucky people), then you'll need to use the Apple File Exchange program (on the Mac) to format a disk for IBM PC compatibility. Mode 2 lets you choose whether an MRC (MC sequencer) song file will be written as a Format 0 or Format 1 MIDI File. Format 0 writes a single track only while Format 1 writes multiple, parallel tracks. You would usually use the latter unless the sequencer you are going to use for editing will only accept Format 0.
Mode 1 then allows you to convert between MC sequencer file format and MIDI File format, or vice versa. The MC screen prompts you to change disks when necessary, and you can also change the name of the converted file if you wish. The final mode, Mode 3, is Restart, which lets you boot up another system disk on the MC-series sequencer - the MRB librarian, for example. Alternatively, you can switch off and on, and go back to using the sequencer.
Conversion of an MRC file to a MIDI File is a very thorough affair - Roland have done their homework well. Testing the software with an MC50, all MIDI information (including system exclusive) and tempo changes gave satisfactory transfers, and the time signature changes from the rhythm track were also correctly encoded into the MIDI File. Steinberg's Cubase and Hybrid Arts' SMPTETrack correctly reformed all information. However, C-Lab's Notator ignored the time signature changes.
MIDI File to MRC transfer gave rather more interesting results. Generally, time signature changes are written to the rhythm track with the actual patterns being filled with rests (a good implementation). Tempo changes are written to the tempo track, and if there are more tracks of information than available sequencer tracks, these are automatically merged into the last available track - track four on the MC500/300 and track eight on the Super MRC/MC50.
Unfortunately, there were problems with various of the sequencer programs. Notator writes the default tempo and time signature to the first track, and any changes to the second. The MRM software only looks at the first track for changes and so doesn't "see" those in the second track. While the use of more than one track for tempo changes is permissible within the MIDI File spec, it has become usual to write any changes to the first track. Without either party stepping outside the MIDI spec, therefore, there is a compatibility problem between Roland's software and C-Lab's.
A bigger problem arose with SMPTETrack. Without going into detail here, there are two distinctly different ways to write system exclusive to a MIDI File, and Hybrid Arts use the method that the MRM software will not recognise. Not only does Roland's software not convert the Hybrid Arts SysEx, it won't touch the song file at all. Surely it could have ignored the SysEx information and converted the rest.
While not all file transfers gave perfect results, the errors are not down to the MRM500 software. Some inaccuracies occur due to the different resolutions of the sequencers - the MC range uses a resolution of 96ppqn (pulses per quarter note) while many of the modern sequencers have double this accuracy. More to the point, few, if any, sequencers correctly write their MIDI data to a MIDI File - yet the MRM converter will accurately handle what it is given. With this and the sheer reliability of the MC-series in mind, I have to conclude that if you use an MC sequencer live, this piece of software will revolutionise the way in which you work.
Price £75 including VAT
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Review by Vic Lennard
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