MIDI for spectrum

slenkar · February 2017

I saw another topic for this in search but it didnt get any informative replies.
I was looking through a magazine and found some MIDI stuff, keyboards and interfaces.
https://wos.meulie.net/pub/sinclair/magazines/SinclairUser/Issue059/Pages/

Did anyone use a keyboard with a tracker program and play back the result?
and MIDI interfaces are supposed to be able to control external instruments as well?

(also on the sound page is 'mega sound' i presume this is an AY chip thingy?
and 2.25 for an aerial switcher including postage and packing aint a bad deal!)

moggy · February 2017

The thing that the spectrum did not have going for it at the time was its non standard interface and its weak, four or was it eight channel capability allied to its simplistic play command and lack of software meant the tracker stuff always won out.
I have used MIDI sometimes professionally from day one(83) and like most people went down the Atari/PC route and don't know of any one who did anything useful if at all with the speccy.

As for controlling other instruments yes easily done I have nine chained together but this can sometimes cause a slight time lag.
Being a controller MIDI is useful in other areas, in my case I used it many times years ago to control light shows for local bands which was a popular thing to do in the absence of more expensive dedicated light controllers.

slenkar · February 2017

thanks :)

zxbruno · February 2017

There are (or were) dozens of topics on this. My hope was to be able to play on a real keyboard and translate it (somehow) to something any Sinclair or Timex machine with AY chip (internal or external) could play. I thought MIDI was the answer and read all the old topics, tried to understand how notes in MIDI compared to the 128K BASIC Play command (it's like comparing apples to oranges), tried many things, gave up. In regards to MIDI interfaces, or MIDI on later Sinclair computers, it does seem like it was always too weak to do anything useful with it. I wanted to send things from a keyboard to a Spectrum, while most topics were about doing the opposite.

Someone posted something on YouTube a couple years ago which gave me a glimpse of hope again. Someone was playing on a MIDI keyboard and the AY chip on the Spectrum was the one playing the notes, but I doubt it was recording them. I don't know what happened to that project.

moggy · February 2017

There is something called MIDI2AY out in web-land but it is pretty useless to be honest. It's a bit like a BASIC compiler in the sense of that the original MIDI file has to be small simplistic and written with conversion in mind rather like preparing a BASIC program for compilation. Also it cannot convert MIDI drum sounds and like a lot of Geek-stuff-for-other-Geeks, it's command line in use and poor on instruction .

The best I could achieve with it was to convert simple 2 handed classical piano pieces into a BIN file(TAP for spectrum) for use with the ZX81 AY BIN player I have but as for converting a 16 channel MIDI song into something useful for AY forget it. :(
An example of its limitations here.

zxbruno · February 2017

Very familiar with it, but it's nice to mention it again for the newcomers, etc.

Another reason why I gave up is because I used to sequence music (record it track by track) and chip music has nothing to do with that. Between 1992 and 2006, I was using digital pianos such as the Clavinova CVP, or Yamaha PSRs, which used 3 1/2 floppy disks to record my humble creations in GM format. Each track was used for only one thing. One track was for drums, another for bass, another for the music notes, etc. When I started reading about trackers, I realized chip music composers didn't compose music the same way. Three channels doesn't mean three separate things. To produce the best results, each of the available channels plays whatever they want when they want it. Also chip music uses a lot of loops and a lot of tricks. Since I play by ear and don't have a way of converting MIDI, or whatever format they use these days, to something the AY chip can play, I moved on. :(

ivanb303 · February 2017

I keep hearing about this non standard MIDI port. What's not standard about it ? I see something that looks like a modem cable marked RS232/MIDI

1024MAK · February 2017

It does not use the standard MIDI connector (five pin DIN socket).
Electricaly, it does not conform to the defined MIDI standard, although it does work.
Both the serial/MIDI/Aux/keypad ports use the general purpose input/output port on the AY chip. There is no hardware parallel to serial conversion chip (UART), so the Z80 CPU has to carry out all the parallel to serial conversion, this is known as bit bashing.
As the data rate for MIDI is different to RS232, so you have to use software that can generate the correct data rate for MIDI.

Compare this to say, an Atari ST which uses the correct connectors (with the correct electrical circuitry), has a UART chip to do the parallel to serial and serial to parallel conversion, and which has the correct hardware to generate the correct clock for the data transfer.

Mark

moggy · February 2017

Nice description Mark.

One of the more serious omissions are the opto-isolators used in MIDI equipment.
https://www.midi.org/specifications/item/midi-din-electrical-specification

Some info from here..
http://forum.arduino.cc/index.php?topic=166030.0
Quote.
"Ground loops will cause horrendous hum, buzzes, and other noises, especially when connected to computerized gear or lighting equipment. The noises are caused by differences in voltage potential from one end of the cable to the other. The remedy, of course, is to run balanced audio lines and to NEVER physically connect the chassis grounds of different pieces of equipment together. MIDI instrument designers understand ground loops. In fact, a major design goal of MIDI, as seen in the electrical specification explanation in the MIDI Specification Document, is to prevent any ground loops that might occur with the MIDI cables. This is done by using a balanced current loop through an opto-isolator and only grounding the MIDI outputs. The MIDI IN connector is not grounded to the receiver's chassis. When done correctly, there are no ground loops and no hum or other noises caused by the MIDI setup."

With the different voltages involved with MIDI kit and the speccies lack of protection there is no way I'd ever connect a couple grands worth of keyboard to it, apart from the fact there is no provision for channel messages, systems exclusive etc other than note on/off. :))

The speccy is to MIDI what Hitler was to reasoned debate.

Scottie_uk · February 2017

What about external midi ports such as those produced by the likes of Cheetah?

moggy · February 2017

Scottie_uk wrote: »

What about external midi ports such as those produced by the likes of Cheetah?

No experience with these Scottie as I went straight down the pro route, but from what I can glean they offered nothing extra apart from standard MIDI connectors and I doubt whether the electronics were any more sophisticated than the speccys' .

No sequencing software as far as I can tell and that which did exist seemed only to support phrase linking not sequences plus simple note on/off no channel,controller or systems exclusive messages and limited polyphony meant that machines like the 4meg Atari STe, coupled to Cubase 2, won the day as far as MIDI is concerned and the speccies lack of memory would be a hindrance insofar as decent MIDI sequencers, having an UNDO function, need a large workspace to store copies of tracks being worked on and when you consider decent sized MIDI files such as orchestral, swing band compositions etc can weigh in at around 70-100k of note content before any controller massages are added you can understand why the speccy was considered a toy amongst musicians.

For all intents and purpose anyone experimenting with MIDI on the spectrum should IMO,just use the PLAY command to make a few interesting noises and not expect to get too much out of it

It would be interesting to hear if anyone has any experience from back then with MIDI on the spectrum but I suspect that game playing was the holy grail for most people given how old they were at the time.

Scottie_uk · February 2017

What about using a midi controller to play the AY?

FrankT · February 2017

I used to make backing tracks using the midi on a 128 toastrack, and a Yamaha PSS480. The midi on the 128 was only one way. It could only send, not receive. I remember it took about 9 months for the midi lead to arrive from Sinclair.

You could send instrument changes, and switch stuff like portamento, vibrato, reverb etc. It was fine for making drum and bass tracks, which I recorded to tape. I modified a tape deck, had a switch for the erase head, so I could record over the top.

Art · February 2017

Very interesting, FrankT. What MIDI lead and software did you use?

By the way, I didn't know anybody using a Spectrum with MIDI, but for example Vince Clarke (Depeche Mode, Yazoo, Erasure) was using a BBC Micro with an external MIDI interface to compose many of his songs, so it's not so crazy. I think it would be perfectly possible to create a decent MIDI sequencer for the Spectrum, with enough memory space for short or simple songs.

moggy · February 2017

Scottie_uk wrote: »

What about using a midi controller to play the AY?

Oddly enough Cheetah did it.

http://www.muzines.co.uk/articles/cheetah-mk5-controller-keyboard/244

@FrankT

Thanks for the feedback Frank nice to know someone used it back then. :)
Same question as Art Really Frank re the software, how did it manage channel messages bank changes etc I only ask as this has suddenly become a wee bit interesting, knowing that someone actually used it successfully I might just experiment with it myself.

FrankT · February 2017

Art wrote: »

Very interesting, FrankT. What MIDI lead and software did you use?

I ordered a midi lead through my local computer shop, who had to order it direct from Sinclair. The toastrack, has an RS232/MIDI socket, similar to a phone socket, but a phone plug would never fit, and the contacts were on the wrong side if I remember rightly.
I used only PLAY in 128 Basic. Let a$-h$="blah", PLAY a$,b$,c$ etc.

moggy wrote: »

@FrankT

Thanks for the feedback Frank nice to know someone used it back then. :)
Same question as Art Really Frank re the software, how did it manage channel messages bank changes etc I only ask as this has suddenly become a wee bit interesting, knowing that someone actually used it successfully I might just experiment with it myself.

Midi channel is set in PLAY statement, upto 8 channels can be used at once. You could send midi controller messages via the PLAY statement as well if my memory serves me right. I only ever had the Sinclair 128 manual to follow. So the commands for sending midi commands are in that small manual somewhere. Can't remember off the top of my head, but it was something like Y or U prefix, followed by the midi control value, which you could find in the back of your Yamaha keyboard manual.

It was a long time ago. Just before Amstrad bought Sinclair.

guesser · February 2017

The serial/midi and keypad/aux ports accept a 631W plug, which is like the standard 631A telephone plug just with different connector keying moulding. The contacts are on the same side - you may be thinking of the joystick ports on the QL which accept the left handed 630W plug.

http://zxnet.co.uk/spectrum/btconnectors

moggy · February 2017

Thanks Frank and Guesser for the replies,some valuable info there. :)

Art · February 2017

Is this cable available somewhere? And is there any software for this cable, which is better than the PLAY command? I don't know if anybody would like to make it, but it would be fascinating to try a real MIDI sequencer for the Spectrum. I use Cakewalk for DOS, which runs in a text mode and it has extremely low system requirements, and I remember a MIDI sequencer for Sam Coupé (Sam has MIDI ports like Atari ST).

ivanb303 · March 2017

I use a 2005 Sony laptop with Ableton 6 and MIDI USB interface, still does the job just fine and that's all I use it for. Someone would have to make the Speccy cable I did find a pinout for it.

ivanb303 · March 2017

@luny

If it does only MIDI out, not much you can do with it but send notes to Cakewalk. The Cheetah interface would be the way to go.

1024MAK · March 2017

If you really want to have a MIDI in, and someone writes the software for this, a opto-coupler (opto-isolator) plus some support components will allow this.

Mark

zxbruno · March 2017

I'd pay good money to have something that could record anything played on a MIDI usb keyboard and translate it to something that could be played on real hardware. Maybe asking for one channel for drums, another one for bass and another one for notes would be too much. But maybe 3-note polyphony wouldn't? All AY channels would be used to play notes only.

Maybe we don't need interfaces or leads. Maybe we just need a utility that can convert whatever format digital pianos use these days, to somerhing that can be played by most 8-bit sound chips.

zxbruno · March 2017

I suspect that if I played and recorded a 1-track MIDI file with no more than 3-note polyphony, tools such as MIDI2CSV would output a file that would have all the necessary info to play it on the AY. Maybe the CSV file would have to be reduced or converted into something first, but I know it'd be doable. I just lack the knowledge to interpret the CSV file.

Art · March 2017

For me, it would be enough to have a MIDI out cable and a good Spectrum MIDI sequencer to control external musical instruments.

MIDI for spectrum

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