When amateur recordists ask about simple stereo mic techniques, the most widely recommended mic array for novices is the ORTF arrangement. The spaced capsules gather inter‑channel time differences in addition to the inter‑channel level differences afforded by the angled polar patterns — the combination delivers a reliable, spacious, and professional‑sounding stereo sound stage. However, rigging two pencil microphones with the required 170mm capsule spacing and 110‑degree mutual angle is often fiddly and frustrating, especially as one of the microphones usually has to be raised above the other to allow the cables to be plugged in.
Thankfully, the age of 3D‑printing has made it practical for designers to manufacture all manner of specialised microphone mounting brackets at relatively low cost. Designs can be created in a CAD system by enthusiasts and shared over the Web for printing at home, or by a commercial company. One such 3D‑printing supplier is an American company called Shapeways, who have a subsidiary in the Netherlands. Look up ‘custom microphone mounts’ on their website and well over 300 different microphone mount designs will appear! Some are simple and basic, some quite ingenious, and some others will probably never work as intended... but the variety is astonishing.
I have recently been looking for a simple mount to make rigging an ORTF array quicker and easier and, after trawling the Interweb, I came across an elegant design by JM Acoustic, who also offer mounting plates for X‑Y, M‑S, DIN and NOS stereo formats, as well as acoustic spheres for omni mics, and various other handy mic‑related contraptions.
The mic clips are available with nominal sizes from 19mm to 22mm, or there’s a ‘universal’ model...
JM Acoustic’s ORTF mount comprises a flat plate with integrated mic clips on the top and bottom surfaces. Strategically placed holes allow mounting directly over a 5/8‑inch mic stand thread, or suspension lines can be attached at three points. It is 3D‑printed‑to‑order exclusively by Shapeways from a black nylon plastic in a matte finish. The mic clips are available with nominal sizes from 19mm to 22mm, or there’s a ‘universal’ model for pencil mics of any size, secured with elastic ‘hair ties’, O‑rings, or rubber bands. There are also options intended for specific mic models. I bought the 20mm clip version, and have found that there is enough ‘give’ in the plastic to cope with 21 and 22mm diameter mics, if fitted with care.
JM Acoustic recommend using the plate with a ball‑joint adapter, so that the mics may be angled up or down easily from a vertical stand. That makes a great deal of practical sense already, but as all of my mic stands have the European 3/8‑inch thread, selecting a ball‑joint adapter with a 5/8‑inch top thread also made fitting the plate easier. (I bought the Onstage MM01, but alternatives include the Triad M1‑R and WindTech MA‑1).
The JM Acoustic website lists the ORTF plate at £25.90 for customers here in the UK, which is very reasonable for a custom‑made specialist device like this, although Shapeways’ processing and shipping charges (plus VAT, our sales tax) brought the final price for a single unit up to £45.34. Tax and shipping differences make it slightly less in the USA ($44.77 in total). It arrived within eight days and the product is perfectly suited for my purposes and the cost is, for me, justified by the minimised rigging time and hassle. I have installed a pair of Rode TF‑5s semi‑permanently on the plate and can now put up an ORTF stereo array in, literally, 10 seconds!