New Software Review: API 2500 Compressor from UAD
If characteristics like “punch”, “aggression”, “energy”, “color” and versatility are what you look for in a compressor, you’d be doing yourself a disservice by not getting your hands on some form or another of the classic API 2500 bus compressor, whether it be hardware or software.
Until recently, those of us without access to the original hardware have had only Waves to thank for offering us with the 2500’s unmistakable tone inside-the-box, through a plugin that dates back to the mid-2000’s.
But look out, Waves—you are no longer the sole purveyor of the 2500 in software form. In late 2016, Universal Audio added the revered dynamics processor to their long list of classic, painstakingly-designed hardware emulations for the UAD Satellite and Apollo hardware platforms.
UAD worked closely with API to design an accurate recreation of the classic 2500 bus compressor.
I’ll precede this review of UA’s stab at the 2500 by noting that I haven’t done a mix in the last 5 or more years that wasn’t peppered with at least several instances of Waves’ API 2500. And if you crack open one of my mixes, you’ll likely find it taking up residence in more places than just my mix bus or stereo subgroups. So how does this new version compare?
Features
Universal Audio claims to have obsessed over the schematics of API’s 2500 rackmount and console-based iterations of the 2500, and say they were granted access to proprietary information that API made available to their eyes only to help make the most accurate emulation of the hardware to date.
In addition to all the classic parameters however, is one distinct feature of the UA 2500 compared to both the hardware unit and Waves’ software emulation: a Mix control for parallel compression applications. Additionally, the UA 2500 offers a “HR” (headroom) adjustment in place of the “L/R Tilt” feature found on the API hardware units, which lets you customize the UA 2500’s internal operating level. Neither of these features are found on the Waves 2500.
Otherwise, the controls on UA’s emulation are the same as on the hardware and the Waves version, and bear the same 5-section layout: Compressor, Tone, Link, Output and Source Meter.
Unlike Waves, UA has retained the smaller, gray pots for the two non-detented controls in the Compressor section (Threshold and Variable Release). Although I seldom find myself using the variable release (see “overchoice”), having this parameter can be key in dialing in just the right amount of movement for your compressed signal.
The values for each parameter across the entire plugin are true to the original hardware unit; no liberties taken here by UA or Waves—and rightfully so.
You’ll find three Knee settings in the Tone section (Hard, Medium and Soft), along with three settings for API’s proprietary “THRUST” technology—Loud, Medium, and Normal—and finally, the option to choose between Feed-back and Feed-forward compression via the “new” and “old” Tone selector.
A closer look at the Tone section of the UAD API 2500
THRUST is essentially marketing jargon for a sidechain EQ circuit that determines how the compressor reacts to specific ranges of frequencies.
In an effort to circumvent the compressor reacting predominantly to low frequency energy (which causes over-exaggerated pumping and a perceived lack of midrange and high frequency energy), the THRUST circuit provides two different options for high-pass filtering on which the compressor’s behavior is based. This ultimately makes for more controlled low end while yielding louder overall volume, and more pronounced mid and high frequencies.
With the Type selector, you can choose the source of the signal for the RMS detector. When “Old” is selected, the unit works in feed-back mode, where the RMS detector receives its signal from the output of the VCA, then feeds the VCA based on a set ratio. This ultimately makes for a very smooth, conservative flavor of compression.
When set to “New,” the 2500 can get aggressive. The unit is feeding forward in this case, which means the RMS detector is sending signal to the VCA at the precise ratio selected.
The Link section is another unique feature available on all iterations of the 2500 that is not found on most compressors. There is a six-step detented “percentage” pot, which determines the degree to which the Left and Right channels are linked. “IND” means there is no linking, then starting at 50% the channels can be linked in increments of 10%.
The Shape control in the Link section has two filters (high pass and low pass)—as well as the option to combine both, creating a band pass—that tell the L/R link what frequencies to not include. This is helpful when particular elements that are weighted to either side excite the compressor, potentially causing the opposite side to compress undesirably.
The Output section features switches for “In,” “Bypass,” and “Make-up Gain.” With “In” selected, the Compression section is bypassed, however signal is still flowing through the 2500. On the hardware unit, “Bypass” is a hard relay from the unit’s inputs directly to the outputs.
When the “Gain” switch is depressed, the neighboring red pot acts as expected—a control for applying necessary output gain after the dynamic range of the signal has been reduced due to compression. With the Gain switch out and the signal below +4dBu, the 2500 offers a convenient automatic make-up gain of sorts, keeping the output around +4dBu based on the Threshold settings. In this mode, the Threshold and Ratio can be tweaked without the overall output level being substantially affected.
Lastly, the HR screwdriver trim—a feature exclusive to the UA emulation—controls the internal operating reference level so that the plugin doesn’t begin compressing before the desired point. It operates in 4dB detented increments from 4dB-28dB.
Interestingly, this seems to be based off of the “L/R Tilt” control found on the original hardware unit, which allows the 2500 to tailor either the left or right channel to allow for a more balanced stereo image of the signal once it is compressed.
The HR trim on the UA 2500 can also be used creatively to expand the sonic palette of the plugin. UA has also conveniently allowed for a quick reset of the HR control via a single mouse click on the “HR,” despite it not appearing as though it’s a button.
You can find a full breakdown of the fixed ratio, attack and release settings available on the 2500 in the UAD v9 Plugins Manual.
In Use
Upon pulling up my first-ever instance of the UA 2500, I found the GUI to be more attractive than the Waves version I’m so used to seeing. The lighting on the VU meters is just more realistic, and I am partial to the fully-black aesthetic of the UA version because it’s truer to the hardware.
Being so used to the sound of the 2500, all of the controls behaved as expected on all sources; there was no night and day difference between the hardware 2500, the Waves and the UA in this regard. Tweaking the attack, release and ratio settings on all familiar sources yielded no surprises, either pleasant or unpleasant—and I really put it through the paces.
The most common places you’ll find an instance of the 2500 in my mixes are my parallel drum bus, overheads, bass (in applications where the playing is more percussive rather than smooth), all types of guitar playing, the mix bus of course, and oftentimes as a first-stage, gentle, slow-attack/fast-release compressor on vocals before I really slam the signal with something else. The UA 2500 was pleasing in all instances here.
The feature I found to be most useful (as predicted) was the Mix knob, and I’m willing to bet that anyone who regularly implements parallel compression techniques would agree. I also found the HR control to be helpful, as oftentimes with the Waves 2500 I’ll have to trim signals down before hitting the compressor to avoid unwanted gain reduction when the Threshold is all the way down. The HR feature also proved to be a nice added subtle layer of texture control.
To Be Critical
I’ll give a disclaimer here that the upcoming sentiment does not apply to UA exclusively, nor is it even a shortcoming of API (or Waves, for that matter). In fact, even considering this a gripe is a massive overstatement.
If I’m looking for smooth, creamy compression, any iteration of the 2500 wouldn’t be my first choice of compressor. When I reach for the 2500, I want aggression. I want obvious, unapologetic, badass compression. And though I find great use in the 2500 when I want to unobtrusively reduce the dynamic range of something before further processing (for example, using a 1.5dB ratio, slow attack and fast release), it wouldn’t be my go-to for warm, thick gain reduction.
That said, ancient wisdom says the jack-of-all-trades is the master of none. The versatility of the 2500 allows it to handle gain reduction tasks of all types, but that’s not to say it would be my first choice for everything under the sun.
Summing it Up
The UA API 2500’s behavior was predictable and in line with my extensive experience using the Waves 2500, which I consider a favorable trait. I wasn’t hoping that UA would reinvent the wheel with their take on the 2500, nor try to fix what isn’t broken. This compressor is a classic for a reason.
The biggest difference to me was in the actual tone of the unit, not the behavior—and the HR control adds great depth and flexibility in this regard. In direct comparison with the Waves 2500, the UA felt palpably richer and more sonically complex. Priced at $299, the UA bears the same list price as the Waves. (Though, at the time of this writing and publication, the decade-old Waves is on sale for a fraction of its normal price.)
Ultimately, I’m happy with anything that bears the API 2500 name—in fact, I’m not sure I could do without it. If you don’t have the budget to pick up a hardware API 2500, you’ll get closer to the real deal with the UA 2500 than you will with Waves, though I’ve been happily using Waves’ 2500 for years.
I strongly urge those who are on the UAD-2 and Apollo platforms to demo the UA 2500. I would be willing to bet that once the trial is up, they’ll find it difficult to go on without it.
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