SPL Machine Head vs Metric Halo Mix Head: which one I use and when

When Metric Halo Mix Head came out, it stayed on my mix bus for months.

It does something special to the highs, adding a nice polish and overall glue to your song. The drive is great, and sometimes it’s just what you need to finalize a track, especially in pop or electronic music, where that extra presence and color can make all the difference.

But then SPL made an original code port of the hardware, Machine Head.

The Metric Halo vibe

Metric Halo plugins, while great, tend to sound very clean: transparent, sterile and digital. Not in a bad way, but if I’m after an analog feel, I usually don’t reach for Metric Halo plugins.

The same thing happened to me with their Sontec EQ. It just sounds like a regular digital EQ to me. The curves replicate the real thing, but I don’t get that “analog magic” feel from it. However, if you compare it to Acustica’s Scarlet (which captures the essence of the Sontec EQ), you automatically get that 3D depth and phase shift that you expect from analog hardware.

Is that good or bad? It’s just different, and it’s great to have both depending on what you are trying to achieve. Sometimes you need things to stay clean and transparent, and on other occasions you need that “extra something”.

So which one is better?

Machine Head feels more like outboard gear to my ears. The way it saturates, the drive, the warmth, and the glue it brings between the mid and side channels is interesting. Creamy. But I do get the feeling that I’m losing a little definition and clarity in the highs.

Mix Head, on the other hand, feels very direct, bright, sharp, “transienty” and with loads of definition, but I don’t get that creaminess and glue in the low and low-mids. It brings some extra life to songs, and for some material that makes things more interesting and lively, but on other songs it can destabilize the mix.

So it’s not about which one is better, but about what your song needs:

• If I want to keep my transients sharp and clear, I go with Mix Head.
• If I’m after vibe and warmth, Machine Head wins for me.

Why they sound so different

My friend Josh Berrios mentioned that when comparing both plugins to the original hardware, Machine Head nulls at -35 dB, while Mix Head nulls at -85 dB.

That surprised me, because I thought the SPL plugin was a direct code port of the original hardware. From what he mentioned, the difference may come from the antique Motorola chips that were used back then.

That’s why the two plugins sound so different.