So, I'm an regular reader and intermittent contributor over at the gearslutz audio engineering forums, and there are recurring debates over there about how to characterize transient response of high-end studio-grade microphones. There's no question that there's a dramatic difference, one that you can hear with your ears and see in a digitized waveform, in the transient response of certain mics that otherwise don't sound so dramatically different. It's especially obvious when recording drums and other forms of percussion, but also has a significant impact on instruments like acoustic guitar. The question is how, other than buying and trying a mic, you can know what to expect in terms of transient response.
One school of thought says that there's a simple mathematical transformation that allows you to take a frequency response plot and a phase response plot, and from the two of them you can derive everything you need to know about transient response. It's also claimed that the phase response of the microphone can be determined based solely on its frequency response. One (or maybe both) of those steps relies on the assumption that the microphone is a minimum phase device (or a time-invariant system.) Advocates of this thinking would say that any mic with especially good transient response has correspondingly higher response at high frequencies, possibly well beyond the range of human hearing in some cases.
The other school of thought says that microphones are imperfect transducers which do not qualify as minimum phase devices, and as such, no assumptions about transient response can be made solely on the basis of frequency response. They say that distortion, mechanical deformation, etc. break down the clean mathematical relationship between frequency response and transient response. There seems to be reasonable anecdotal evidence to support this, particularly in the case of ribbon microphones. Many studio-grade ribbon microphones exhibit very poor frequency response above 10-15kHz, but seem to have fantastic transient response, capturing a more powerful attack on plucked strings and percussion than their modest frequency plots would predict.
The people making the pro-math argument seem to know what they're talking about, and make fairly convincing arguments... but the other side's argument about non-linear, non-ideal behavior from real-world microphones also makes a lot of sense to me, and my personal experience thus far, not to mention the opinions of an awful lot of audio engineers whom I respect and trust, support the idea that transient response in microphones isn't defined exclusively by frequency response. I've tried to provide a reasonable summary of the salient points, but here are links to two of the larger debates for anyone who's interested in hearing both sides of this debate:
https://www.gearslutz.com/board/geekslutz-forum/1231275-there-measure-mic-transient-response.html
https://www.gearslutz.com/board/rem...diaphram-fast-small-diaphrgam-condensers.html
I trust the engineers here more than most of the people over at gearslutz when it comes to math, science, and theoretical stuff, so I wanted to get your opinions. Keep in mind, I'm not questioning the validity of these mathematical transformations for testing electronics (preamps, transmitters, etc.) but just specifically for microphones. I'd love to hear what you all think.
Thanks!
One school of thought says that there's a simple mathematical transformation that allows you to take a frequency response plot and a phase response plot, and from the two of them you can derive everything you need to know about transient response. It's also claimed that the phase response of the microphone can be determined based solely on its frequency response. One (or maybe both) of those steps relies on the assumption that the microphone is a minimum phase device (or a time-invariant system.) Advocates of this thinking would say that any mic with especially good transient response has correspondingly higher response at high frequencies, possibly well beyond the range of human hearing in some cases.
The other school of thought says that microphones are imperfect transducers which do not qualify as minimum phase devices, and as such, no assumptions about transient response can be made solely on the basis of frequency response. They say that distortion, mechanical deformation, etc. break down the clean mathematical relationship between frequency response and transient response. There seems to be reasonable anecdotal evidence to support this, particularly in the case of ribbon microphones. Many studio-grade ribbon microphones exhibit very poor frequency response above 10-15kHz, but seem to have fantastic transient response, capturing a more powerful attack on plucked strings and percussion than their modest frequency plots would predict.
The people making the pro-math argument seem to know what they're talking about, and make fairly convincing arguments... but the other side's argument about non-linear, non-ideal behavior from real-world microphones also makes a lot of sense to me, and my personal experience thus far, not to mention the opinions of an awful lot of audio engineers whom I respect and trust, support the idea that transient response in microphones isn't defined exclusively by frequency response. I've tried to provide a reasonable summary of the salient points, but here are links to two of the larger debates for anyone who's interested in hearing both sides of this debate:
https://www.gearslutz.com/board/geekslutz-forum/1231275-there-measure-mic-transient-response.html
https://www.gearslutz.com/board/rem...diaphram-fast-small-diaphrgam-condensers.html
I trust the engineers here more than most of the people over at gearslutz when it comes to math, science, and theoretical stuff, so I wanted to get your opinions. Keep in mind, I'm not questioning the validity of these mathematical transformations for testing electronics (preamps, transmitters, etc.) but just specifically for microphones. I'd love to hear what you all think.
Thanks!