It's a fair question. After all, there are so many devices that can generate a MIDI Clock all while doing other more interesting things. You probably have something like that already. The ability to send Clock almost seems ubiquitous.
So why invest in a dedicated MIDI Clock? It comes down to having the tightest sync while providing greater control in all areas related to synchronization.
Allow me to spell out the case for using a dedicated clock device. I promise there are some advantages that won't be so obvious at first.
- Generating the most accurate Clock signal requires Priority. When a device like a programmable MIDI controller, sequencer, drum machine or DAW is running, the priority is likely not going to be on its ability to send MIDI Clock. Sending clock out of a MIDI port (or any other sync port) shouldn't have to wait for free computational cycles. A well-designed dedicated Clock makes sending clock signals the highest priority. Not to do so will result in increased Jitter and/or Latency.
- As in #1 above, running a DAW on a computer is especially notorious for MIDI Clock instabilities. Everything may work well at first, but as the project grows and the demand on computational resources and multi-tasking increase, the generation and output of MIDI Clock tends to suffer ... badly. Some dedicated devices, like CLOCKstep:MULTI, have a special mode for syncing from a DAW that doesn't involve MIDI Clock. This mode is commonly known as "Sample Accurate Clock". The details are beyond the scope of this article, but worth mentioning. You can read about Sample Accurate Clock here.
- Independent control of a dedicated Clock provides the most flexibility. When other devices, such as a synths, drum machines or sequencers are designated as the Master Clock, it almost always means that the device cannot halt the other things that it is doing without stopping the Clock as well. You have to find ways to keep Clock running even during moments where you don't want the machine to be doing anything else. With a dedicated Clock that you control independently, you can manipulate every other device without being concerned how it will effect the clock.
- Splitting and distributing the Clock signal alone is easiest with a dedicated Clock. When clock comes at the start of a MIDI Chain before any other messages are present, the signal can be routed through a hub and distributed to larger systems.
- A device like CLOCKstep:MULTI acts as a bridge for various Clock signals in a way a non-dedicated device do not. In a system comprised a DAW, Sequencers, Synths, Loopers and Samplers, you are likely to run into a variety of sync protocols. Having a dedicated device that can translate between Audio, MIDI and Votages using DIN, USB and TRS connections proves invaluable in these circumstances.
- Sending a variety of Sync Rates. MIDI Clock is 24 PPQN, that never changes, but when you mix MIDI Clock with other sync protocols such as Control Voltage outputs, you'll need some sort of utility device to divide the sync rate down to a variety of other compatible sync rates. Some dedicated clocks can do this without requiring any other gear.
- Monitoring the tempo can be done discretely. Not every dedicated Clock device also acts as an Audio Metronome the way CLOCKstep:MULTI does. The ability to route a discrete click track that's independent from any other audio signal will facilitate easier monitoring for a band. Configuration of the Metronome may also be more comprehensive in a dedicated clock than what is offered in non-dedicated devices. Read How Click Feel Matters.