The Soyuz SU-13 FET Small Diaphragm Condenser, much like the entire Soyuz line, is quite surprising. To be honest, for what I do, and what I look for in mics – I don't find much use for SDCs. Their biggest advantage is a faster transient response, which make them very well suited for drum overheads and percussion. However, a faster transient response is not a big advantage (or need) for acoustics (which are clearly more complex than just the transients they give off from picking). I have three large diaphragm condensers that work great on acoustic, so there is no real need for me to invest in an SDC, in that regard. This is all personally speaking (as someone that is invested in the prog-rock/metal world).
That is where the Soyuz SU-13 is so surprising. Firstly, the build quality is amazing. It is weighty. The metal work is the real deal – high quality machining, nice finish, thick and durable. It has a threaded interchangeable capsule design (the pad is an inline device that threads in between the body and capsule), and the performance is impressive. There is detail to the smooth musical upper mids, coupled with a soft top end. The low mids have a warmth/fullness to them that stands out, but is not over powering. The mids really brought out the wood and body of my Taylor. The bottom end is present, but rounded with a gentle roll-off. This provided depth, but not more that is actually needed. Whether using a heavy, medium, thin, or finger picking, the results were always warm and woody, with that smooth detail that allowed the acoustic to maintain a proper cut. After experiencing how well the SU-13 and my Taylor got along, I found myself impressed with a SDC. One that if I only ever used on acoustics, I would be happy to own. The tonal character that the SU-13 provides is also something that I believe would perform very well on bowed stringed instruments, giving them the detail you need, but with a richness that brings them forward.
With the SU-13, Soyuz has managed to make something that is pleasing, impressive, and properly charactered, all while doing it's own thing. The SU-13 does not sound like anything else (at least nothing else that I have personally used). Yet, with the full warm and woody tone it provides, that makes it a superb alternative to an industry standard SDC that is often used on acoustic stringed instruments. So if you are looking for a SDC that can be on par with that industry standard vintage acoustic guitar mic, will work on orchestral strings, and also handle drums like a champ – give the Soyuz SU-13 a look.
The Soyuz SU-13 comes in four difference configurations: