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Equation F20 Large-Diaphragm Mic

The F.20 is a versatile, well-built, and affordable LDC that excels in many applications — a “winner,” deems our reviewer.

A relative newcomer, the Nashville-based manufacturer Equation Audio has unveiled its latest microphone, the F.20 super-electret, large-diaphragm condenser.

Designed as a multipurpose mic, it is aimed at a broad range of users, from seasoned industry professionals to discriminating self-recordists.


The F.20’s first example of Equation’s promising attention to detail is in its packaging; it comes in an attractive and soft, zippered and tweed-covered clamshell carrying case filled with cut foam with an included metal pop filter. [According to the manufacturer, its unique soft “bag” style case “allows for great protection without impacting the total cost,” explaining that some “hard cases at the same cost tend to be easily destroyed, contain cheap foam, and afford no better protection and are cosmetically attractive until used a few times.” — Ed.]

The F.20 has a 16 dB pad and a highpass filter (at 80 Hz). Its switches are located on the front side of the microphone, distinguished by the Equation logo. The microphone is internally shockmounted, using a straightforward yoke design for mounting to a mic stand. For its head amp, Equation explains that the F.20 utilizes “a completely new” design claiming low noise (80 dB S/N), high headroom 150 dB max. SPL @ 1 kHz), and a very broad frequency response (according to manufacturer-supplied specs, 20 Hz to 20 kHz with notable 3-5 dB bumps at around 3 kHz to 6 kHz and a nearly 6 dB peak around 12 kHz). The transducer is an electret type with a diaphragm that measures 0.8 inches (20 mm) and sports a supercardioid pattern.

In Use

First up for the F.20 was vocals, comparing it to several vocal mics in its price range and a few costing three times as much. The results with the F.20 were very nice; in comparison to the other mics I auditioned, it had a smoothness to the frequency response the others couldn’t match, especially on female vocals. On “darker”-sounding singers, the mic didn’t place quite as high on the list, but I found that, even when EQ’d to add some air, the F.20 still didn’t become harsh-sounding.

Even though the F.20 is a super-cardioid, it possesses a subtle proximity effect that proved quite useful for our vocalists and never became overbearing or muddy. One subtle quality I noticed during mic comparisons and during mixdown was that the vocals recorded on the F.20 seemed more focused in the stereo image, and slightly more forward-sounding than the other models tested. This phenomenon allowed them to sit in the mix nicely and still be heard without as much processing as other mics.

During my long term testing of the F.20, I found several more good applications, such as on acoustic guitar. There, it sounded very pleasing and full spectrum without too much low end, and without the harshness that some condensers accentuate via pick noise. With the 16 dB pad engaged, drum overheads also sounded good. It was probably my second favorite of all my overhead choices, again showing off its excellent imaging. The mics blended well with the close mics. Close miking on drums for pop/rock was my least favorite application for the F.20, mainly because I prefer (or am accustomed to) dynamic mics on drums. With appropriate EQ, they still sounded quite good, though; for different styles of music (say jazz, for instance), they might be a welcomed choice on drums.

I should note that my favorite app for the F.20 is on an organ Leslie cabinet. In the past, I have always preferred dynamic mics on Leslie cabinets, partly because they pick up less wind noise, squeaks, etc. With the F.20’s pads engaged and the flanking the top rotor in a stereo pattern of the Leslie, I was really impressed; it translated all the richness desired, and the distortion and overtones came through during the mix better than with the dynamic mics I typically use.


It’s clear that Equation Audio aimed for a lot of versatility in the F.20. They aimed to make an AKG 414-type of microphone, yet more versatile, more forgiving, and at a lower price point. In my opinion, they have accomplished that goal. Overall, it has a velvety smoothness that comes through on vocals, a variety of instruments, in a variety of positions. It does all this while creating a solid image in the stereo field that will be appreciated even more on mix day. At under $600 street, it is a winner in my book.

Randy Poole is an engineer and mixer based in Nashville.