Blagsheets - MIDI

Crow Hill Blagsheets
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Thanks to everyone who contributed to helping perfect the instruments and microphones blagsheets.

Now we’d like to call on your fact checking and proof reading skills for a new blagsheet:

Blagsheet #07: MIDI

Here is the beta version to take a look at:

https://web.thecrowhillcompany.com/blagsheets/BLAGSHEET_MIDI_v1.0_NEON_DRAFT.pdf

and if anyone has any comments, suggestions or spots any errors, feel free to add them below.

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A few things I noticed:

  • HISTORY / WHAT IS IT?
    • para 2 heading “HISTORY” - spacing above/below should be consistent?
    • para 2 sentence 1 - comma should be a conjunction “…legitimise their operations and to increase…”
    • para 2 sentence 4 needs a subject “…of music. MIDI is something”
    • para 3 sentence 2 is a sub-clause of the first - use a semi-colon or dash “…Korg and Kawai; that an…”
    • para 4 sentence 4 - unnecessary comma in the expansion of the MMA acronym, plus capitalisation of MIDI “…MMA (MIDI Manufacturers Association)…”
    • para 5 sentence 1 - I think “8bit” is more conventionally written with a hyphen “8-bit”; but this is a personal preference
    • para 5 sentence 2 - I’m not sure that the transmitter and receiver are inevitably sound/music related. See Other applications on the MIDI Wikipedia page
    • para 5 sentences 3, 4, & 5 - The explanation of/comparison to piano rolls is a bit garbled. Alternative version: “It contains no sonic information, but instead encodes a stream of events - such as note-on and note-off - which the receiving device must interpret. A MIDI stream has similarities to sheet music (where a musician interprets written notation) and to a paper piano-roll, which a mechanical player-piano interprets to recreate a musician’s performance.”
  • IN, OUT & THRU
    • para 1 sentence 1 - capitalisation - “MIDI…”
    • para 1 sentence 2. It might be clearer to split the discussion of details of the communication protocol (channels) from the description of the physical cabling/ports. Maybe rewrite as "MIDI allows several devices to be connected together and controlled by one another; each connection is made over a uni-directional cable. Different ports are…
    • para 2 - maybe spell out the flow of data as related to the MIDI ports? "In this example, a performance is converted into MIDI by the synthesiser; the MIDI data representing the performance is transmitted from the synthesiser’s MIDI OUT port to the sequencer’s MIDI IN port. Later, the sequencer transmits the MIDI data from its MIDI OUT port back to the synthesiser’s MIDI IN port to replay the performance. The synthesiser outputs…
    • para 3 - maybe add something at the start of this para about a single MIDI stream not being limited to controlling a single device, to give a context for channels?
    • para 3 sentence 3 - typo - “its” not “it’s”, capitalisation “MIDI OUT.”
    • para 3 sentence 4/5 - typo - “its” not “it’s”. Maybe clearer to word as "The second (upper pictured) synthesiser plays the instructions contained in the MIDI stream on its own channel, ignoring any instructions for other channels; it passes on all the MIDI data it receives via its MIDI THRU port.
  • WHY IS MIDI SO “QUIRKY”.
    • General - there’s nothing in this section about SysEx messages. Maybe add a footnote? Something like “The MIDI standard also allows manufactures to define SysEx (system exclusive) messages that are device-specific, and which are not constrained to 3 bytes per message; using extended messages, many different kinds of custom hardware and software can be controlled by MIDI. This makes MIDI almost infinitely extensible, and is part of the reason for its longevity.”
    • para 2 sentence 1 - capitalisation “MIDI”
    • para 2 sentence 1 - might be worth including “asynchronous serial” in there somewhere - suggest “MIDI is a stream of asynchronous serial data…”
    • para 2 sentence 2 - nested brackets are a bit clunky - replace the outer set with a semi-colon?
    • para 2 sentence 2 - suggest “…was agreed by the MMA.”
    • para 3 sentence 1 - suggest "To communicate meaningful data, the individual bits are evaluated in a groups of 8, known as bytes.
    • para 3 sentence 2 - suggest “In the MIDI protocol, data units are 1 byte (8 bits) wide - so MIDI is as an 8-bit system”
    • para 3 sentence 3/4 - comma not full stop "…made up of 3 bytes, with byte 1…
    • para 3 sentence 4 - suggest “…two data values.”
    • para 4 and beyond - this description skips any mention of the two “framing” bits (0 for start, 1 for end) that delimit the bytes in a MIDI message. Because of the framing bits, each byte of a MIDI message is encoded as 10 bits (start bit, data byte, end bit) - this reduces the theoretical data rate from 31.25 kbit/s to 25 kbits/s. Perhaps too technical a detail?
    • para 5 - possibly another too-technical detail, but the position of the MSB is determined by the “endian”-ness of the protocol - MIDI is a big-endian protocol, meaning that the highest valued bit is on the left of the byte. Other protocols/file formats (including WAV audio) are little-endian, where the highest-valued bit is on the right of the byte
    • para 9 (starting "With the 8 possible…) sentence 1 - suggest hyphenating “channel-dependent”
    • para 11 (starting “SO, we can…”) sentence 1 - capitalisation of “So”
    • para 11 sentence 3 - “channel-dependent”
    • para 11 sentence 3 - abbreviation of number seems to have misfired - use the “numero” character?
    • para 12 (starting “SO, with”) sentence 1 - capitalisation of “So”, “bytes”, “data” (first instance)
    • para 12 sentence 1 - suggest “..each of which have 8 bits…”
    • MIDI message diagram:
      • what’s labelled as “LSB” on each data byte should be labelled “MSB” - unhelpfully, MSB and LSB can mean most/least significant byte or bit; in the protocol message definition it’s about bits.
      • the underscores sort-of represent the framing bits, but it would be more correct to have one underscore at the beginning and end of the three-byte sequence and two underscores between each byte. Again maybe splitting hairs.
    • para 14 (starting “We hope”) sentence 1/2- suggest “…less arbitrary and more pragmatic, being based on the 8-bit technology available at the time, balanced with the desire to make…”
    • para 14 sentence 3/4 - suggest “..these days - electing instead for far-superior USB connections - don’t be fooled into thinking that this is no longer MIDI.”
    • para 14 sentence 5 - remove “packages or”
    • para 15 (starting “If there is one quirk…”) - this is a bit disjointed. I think you are trying to say something along the lines of “Isn’t it surprising how well-supported aftertouch is by the MIDI protocol, given that it is so little used; perhaps this is down to Yamaha’s ambitions for the CS80.”
    • para 15, sentence 5/6 - move this to the GM section?
  • THE 5 PIN DIN CONNECTOR
    • Title - hyphenate “5-PIN”
    • para 1 sentence 1/2 - join these with a comma, capitalisation "…“separates systems", the DIN…”
    • para 1 sentence 2 - hyphenate “mid-20th century”
    • para 1 sentence 3/4 - join these with a comma, hyphenation “…starting as a 3-pin connector for mono sources, the 5-pin connector”
    • para 2 sentence 1 - typo “Its” not “It’s”
    • para 3 sentence 1,2 - join with a comma “…or MIDI as it became known), it…”
    • para 4 sentence 1 - hypens, capitals, commas, typos “…these now-defunct cables it was suggested that the 5-pin DIN connector could be adopted; its shielding…”
  • GENERAL MIDI (GM)
    • Footnote - a point implicit here is that MIDI encompasses both a communication standard and a file format - this is something that should perhaps go into the intro section at the top of the poster.
  • MIDI NOTE NAMES VS NUMBERS
    • footnote sentence 4 - typo “its” not “it’s” - “as its keyboard”
    • footnote sentence 5/6 - join with a semi-colon, “protocols” feels like the wrong word in this context - suggest “..from these two conflicting definitions of middle C; Roland’s…”"
    • footnote sentence 6 - clarification - suggest “..see which convention they’re…”
    • footnote sentence 6/7 - suggest - "…their flag to; for avoidance of doubt middle C is always…
    • footnote sentence 7 - use “numero” character?
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Thanks so much for your help Ed. Here’s the latest version: https://web.thecrowhillcompany.com/blagsheets/BLAGSHEET_MIDIv1.1.pdf

2 Likes
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These are great. Thank you for providing these resources! There is some confusion for me regarding the Pitch Wheel data bytes. DATA 1 and DATA 2 are listed as (from) and (to). This led me to believe that a movement range was being sent. It is my understanding that the combined value of these 2 bytes indicates the absolute position. A little more detail on this value would be helpful. Thank you!