Really enjoying the API plugins

The API plugins – I’ve owned them for a while but I never had a chance until recently to really dig into them.

They’re a lot of fun!

For one, the API 550a has a handy “filter” switch that tapers the low & high end of a track. This makes the 550a my most frequently used API eq because it’s so fast…

But I also discovered the magic of the API eq curves. In the documentation it describes them as being wide Q at low settings and high-Q (narrow) at high settings. I had to look at the response through spectrum analysis to understand what’s happening —

It’s not that the WHOLE eq curve changes shape – rather, as you boost higher and higher, the louder parts taper. So even boosed a lot it’s never a nasty narrow band spike – it’s a wide boost that tapers as it increases.

As it turns out – that shape is amazing for sculpting the EQ of a sound.

One thing I love is how the EQs are notched, so you dial them in with increments. While this might seem unusual – it’s actually a really FAST way to work because you’re less fiddly with the knobs. In use, it’s just enough control to get what you need while moving quickly.

550b gives you 4 bands for greater detail of your EQ sculpting, but it doesn’t have the bandpass filter.

API 560 is a graphic EQ, and the bands have the same behavior where they start wide and get narrower as you increase.

I’ve never been a graphic EQ kinda guy before, but I actually love this one once I understood the EQ behavior.

The API 2500 is the compressor, and wow is it great!

It’s strange in that it offers notched positions, but also a “variable” position for the attack. What a strange design decision for API, but again — the notched positions let you move fast but you can get finer control on the release if you need it.

The KNEE shape is handy - HARD/MED/SOFT all sound very different, so it’s important to set correctly. The thrust control shapes the EQ of the detector source, which solves the problem of having a detector over-respond to the bass frequencies. Perfect.

I don’t understand the NEW vs OLD feed forward/back settings. I read the manual, looked at the wiring diagram – and I still don’t understand the difference it makes.

This compressor has auto makeup gain. I’ve grown to REALLY appreciate auto makeup gain because you can hear the change to your dynamics without changing the level! You can turn it off though, if needed.

Finally — all the plugins have an ANALOG switch. I keep seeing in other forums that “the analog button just adds noise” — that’s not true at all!!!

I looked at the plugins through spectrum analysis. Run a 100hz or 1khz sine wave through and you can see the harmonics that are added to the signal. All the EQs are pretty much the same in that regard, and then the compressor adds an additional order of harmonics that the EQs don’t.

The plugins also have an “IN” button which allows you to get the harmonics processing without the additional EQ / compression. Just passing through the analog emulation circuitry.

I always enable the analog buttons. It’s part of the fun, and part of the color. Otherwise we could just use a cleaner digital style EQ/compressor.

The API plugins have become some of my frequently used tools now. The EQ handling, filter switch, and easy setting of compression makes it a winner for me.

I do wish they would split the dual-knobs, though. They matched the hardware, which is cool except those are a little fiddly to operate with a mouse!

Still, these made it into my “favorite plugins” list.


This API plugin is really good and helpful.

I also have all of them but have never, up to now, spent time trying to really use them. Thanks to you, I’ll give them a try this weekend :slight_smile:


Yeah that eq filter design is known as “Proportional Q” and does exactly as you state. The idea is as you boost or cut the Q is automatically adjusted so the energy remains pretty much the same. It’s quite clever and musical at the same time.

That compressor is a killer too. And indeed those all important API harmonics are in with the Analog switch, so it doesn’t just contribute noise. I find turning it off is like throwing the baby out with the bathwater. Although, there is such a thing as too much noise.

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