This is totally under the control of the software you're using to 'play' the midi file.

Some may not allow this at all, others may allow but it's too clumsy to be practical re what you want.

I've just checked in the SynthFont system that I use to play midi files using VST sounds. This has a control for Speed, you can click for either 0.1% or 0.01% either faster or slower. and when you do this there's a message showing briefly regarding keyboard alternatives which might be even more convenient as the area to click on is fairly small.

You can download SynthFont for free, there might be other systems that do something similar?

Geoff

Hi again, Geoff! How are you? Great to 'see' you again -- you've been so generous (and patient) with your advice on previous questions. Thanks so much for the reply and SynthFont clue, even though it only offers (on my problem) a slight variant.

Hello Nelson,

I've got your profile to list your other threads, but I don't remember anything from the titles.

If SynthFont does not go far enough, you'll need to look elsewhere. There may be something, maybe try searching using the word 'conductor' as part of your search keys?

Otherwise, You can try to write your own code - maybe others would be interested as well? You need something that will play the file, but respond to some physical control, maybe a wheel as might be used on some keyboards. But, receive the messages from that device, and convert them into Tempo Change messages, rather than the initial Controller.

A midi file can have any number of tempo change instructions, and there's no reason why the playing process could NOT receive extra tempo change messages 'on-the-fly'. The software would need to respond to the messages exactly as it would respond to the tempo changes within the midi data.

Geoff

Hi Nelson,

Back in the dark ages, before the first Black Death, there used to be a piece of software known as MIDI Maestro MM4, I think the 4 was for the version number.
It allowed the pitch bend wheel to be used to bend the tempo faster or slower away from the tempo defined in the SMF.
There's a CNET review on-line if you search.
I don't think it's been updated since Win XP tho'.

There will be, apparently, a device coming out soon called MIDronome, which will allow you to control tempo actively.

Regards,
JohnG

Thanks JohnG. I see MIDI Maestro has been kept up, but it'll never work for me

https://www.youtube.com/watch?v=UNyhcGIJfEU&t=174s

MIDronome is already a thing too -- close yet so far from what I'm envisioning

https://www.youtube.com/watch?v=hkw9dmLfkZQ

18 minutes of basic instruction using how many pieces of hardware, ouch. Guess I can only hope that Reaper's and/or Audacity's developers will see this, dig it and race to be the first to offer it inline. I promise you folks, people would have been using and enjoying the daylights out of a tempo slider all this MIDI era if it were standard in DAWs 😉

Can you describe more what kind of control you had in mind? For example, do you want a knob or slider to adjust the tempo during playback? A button or keyboard key you can tap a beat on?

MIDI sequencers often let you synchronize the playback to incoming MIDI timing messages (MIDI Timing Clock, Start, and Stop). Then if you have another program that can output MIDI timing messages, you can connect it to the MIDI sequencer using a virtual MIDI cable like loopMIDI for Windows.

For example, Pocket MIDI has a knob window to transmit MIDI Timing Clock messages at rates from 5 to 300 quarter notes per minute, and another window to transmit the MIDI Start and Stop messages if needed. I used loopMIDI to connect it to MIDI sequencer Sekaiju or Cakewalk, then set up the sequencer to use the incoming timing messages. When a MIDI file is playing in the sequencer, I can drag the tempo knob in Pocket MIDI to control the playback speed.

Instead of a computer program, you could use a physical MIDI keyboard or MIDI controller that can transmit MIDI timing messages and lets you control the tempo with a knob, slider, or button.

JohnG mentioned software that lets you use the Pitch Bend wheel on a MIDI keyboard to control the playback tempo. Here's another program I know of that can do that:

You can use the falling notes piano game Synthesia in its "Watch and Listen" mode to play back MIDI files. You can go to its Shortcut settings to set up a Pitch Bend wheel to control the tempo.

You can try Synthesia for free, but it will only play the first 20 seconds of a MIDI file. It includes built-in songs and some of them are unlocked allowing you to preview them in their entirety. Synthesia's normal price is $40, but it's usually $30 during frequent sales throughout the year, or $20 on Black Friday.

More ideas:

vanBasco's Karaoke Player has a tempo slider.

I previously mentioned setting up Synthesia to use a MIDI keyboard Pitch Bend wheel for tempo control, but Synthesia also has default keyboard and mouse shortcuts for tempo control:
Up or Down changes the tempo in units of 10 percentage points.
Ctrl+Up or Ctrl+Down changes the tempo in units of 1 percentage point.
Ctrl+mouse scroll wheel changes the tempo in units of 3 percentage points.

I guess vanBasco's Karaoke Player and Synthesia are actually MIDI players and not MIDI sequencers like you asked for. But if using a MIDI player program is acceptable for you, they're probably more likely to have a tempo adjustment control.

Another alternative: MuseScore is focused on music notation editing, but it can also record live MIDI input.

MuseScore 4 has a horizontal tempo slider in its Play toolbar when it's undocked.

MuseScore 3 has a vertical tempo slider in its Play Panel. (Note: The Play Panel is resizable, I have mine docked on the right side of the screen and the vertical sliders stretch to a larger size. I only mention MuseScore 3 because that's the version I still have, MuseScore 4 came out earlier this year and I haven't investigated upgrading it yet. If you also have MuseScore 3 already, maybe you wern't aware of its tempo slider.)

Thank you so much for all these ideas, Bavi! Only an on-screen slider will do -- built-in is so much better and I need total instant active control during playback. There are no physical controls on my instruments that could be so dedicated and I have little confidence in my abilities to reassign them.

I see VanBasco's Karaoke Player DOES have what I'm looking for. Maybe it will do during my playback situations. I do need Piano Roll view showing at all times -- maybe VBKP has that feature. I know there'll be a learning curve -- hope I don't break down in it.

Am checking your other suggestions out via Google and YT. Appreciate every one of those MuseScore details. Where's the MIDI feature in version 3? All it wants to do is set up score writing.

This function is available on my Drumstick multiplatform MIDI file player, (which is available for Windows, Linux and Mac) and also on Drumstick MIDI Monitor and the Drumstick MIDI Player. The last two apps are Linux only.

[quotePost id=17908]Appreciate every one of those MuseScore details. Where's the MIDI feature in version 3? All it wants to do is set up score writing.[/quotePost]
I had only quickly tried out MuseScore 3's MIDI record ability before my previous post and I misunderstood it a little bit. I incorrectly believed the "real-time (automatic)" input mode could make a verbatim recording of MIDI input notes. Now I've read more about it, it is more like an automatically advancing step-input mode: You click one of the note value buttons in the toolbar to select the step size, then you hold down a key on your MIDI keyboard and watch the new note on the staff increase in size the longer you hold it down. If you want to try it out, here are some notes:

If you have more than one MIDI device, go to the Edit menu, Preferences command, page "I/O", drop down box "MIDI input" to choose the device you want to use and click OK.

You have to have a blank score before you can record, but you can just use defaults at first to play around with it:
Click the New button in the toolbar (or go to the File menu and choose the New command).
On the page "Enter score information", click Next.
On the page "Choose template file", look under "General" and click either "Treble Clef" or "Grand Staff", then click Finish.

There's a button in the toolbar to enable MIDI input -- it's the 5-pin DIN port icon (just to the left of the "rewind to start" and "play" buttons). Make sure that button is enabled.

In the toolbar with the music note values, the first button is for the note input mode. Click the down arrow and change it to "Real-time (automatic)".

Continue reading how to use the "real-time (automatic)" or other note input modes at the handbook links above.

Looking to capture your MIDI creations on your Android phone?

You've got options! While the landscape can be a bit fragmented compared to desktops, there are some great mobile tools available.

Here's a breakdown to get you started:

Hardware:

MIDI Controller: You'll need a MIDI instrument or controller to record your performance. This could be a keyboard, drum pad, or any other device that sends MIDI data.
OTG Adapter (Optional): If your MIDI controller uses a USB connection, you'll likely need an On-The-Go (OTG) adapter to connect it to your phone's USB port.

Software:

There are several apps that can record MIDI on Android. Here are a few to consider:

MIDI Recorder: This is a simple and free app that lets you record MIDI data and save it as a .mid file.
Mobile DAWs: Many Digital Audio Workstations (DAWs) available for Android also support MIDI recording. Popular options include Caustic, Korg Gadget 2 (LE), and Audio Evolution Mobile (paid for USB MIDI). These offer more features for editing and sound creation alongside MIDI recording.

Choosing the Right App:

The best app for you will depend on your needs. Here are some things to consider:

Features: Do you just need basic recording, or do you want features like editing and sound creation?
Price: Some apps are free, while others require a purchase.
Ease of Use: How comfortable are you with music production software?

For <a href=" removed link " target="_blank" rel="noopener">Software Developers:

If you're a developer looking to build your own MIDI recording app, here are some resources to get you started:

The Android MIDI API provides tools for working with MIDI data on Android devices removed link
Open-source projects like MIDI Recorder (mentioned above) can offer a good reference for building a basic MIDI recording app removed link