Topic: Question about Soundfield ST250

[beauharlan]

Hello, I have a person who left me a Soundfield ST250 windshield but I have no experience using it. Does anyone who has used it tell me the pros and cons of this product in practice? Thanks.

[todd e]

if you mean you have been left the full microphone and 'box/cable' that allows changing of microphone patterns, then yes.  it's a fantastic microphone set that allows for multiple polar patterns.

https://issuu.com/filmmaker8.com/docs/soundfield_st250_user_guide

It is discontinued now, however when i ran it - it had a cable which would allow connectivity to your recorder, via full XLRs.  I think you can run omni, hyper, cardiod, or mid-side.
I demo'ed from SoundField and they sent this unit to me, which I was asked to send along to NASA after a month of constant use.  What a great customer service program!

https://makenoiseproaudio.co.uk/products/ams-soundfield-st250-1

[Gutbucket]

I've not used the Soundfield ST250 specifically, but am familiar with ambisonic mics in general and may be of help.

Think of an ambisonic mic as a very flexible X/Y or Mid/Side stereo microphone.  When used by itself it is limited to coincident "single point" stereo microphone configurations, but you can dial in any combination of pickup pattern and inclusive angle you like.  In some cases you can do that after the recording was made, in other you need to decide which combination of pattern and angle to use prior to making the recording.

Generally there are two categories of ambisonic mics:  Those which require a dedicated power-supply/preamp/decoding box (ST250 is one of those) which are capable of outputting a ready to use stereo signal, and others which shift the ambisonic decoding to a post-production process done later on the computer or a hardware unit.  Some in the second category can be plugged directly into the XLR preamps of a four channel recorder, while others still require a dedicated power-supply and just offload the processing part.  In either case, good calibration of the microphone is critical for good performance.  That's achieved in the dedicated power-supply/preamp/decoding box via adjustable trimmers. If needed, Len at CoreSound may be able to offer that service, as they both make ambisonic mics and create calibrations for other ambisonic mics.  Mics that do the processing later on the computer require recording with rather closely matched gains across all four channels, so in that case a recorder with digital gain controls is helpful, and some use calibration files specific to each microphone which get applied prior to decoding.  Those calibration files essentially take the place of the trimmers in a dedicated power-supply/preamp/decoding box.