rob aylestone
Moderator
Not sure if shotgun mics have any interest here - but I've got quite a few and it's very common for people to like/dislike the sound of individual mics, and to appreciate that longer is more directional. I thought I'd try to tie it down a bit - so I hit on a test idea. Line up 4 mics of different lengths and put them on a T bar, so they can rotate. Point them at a speaker with pink noise, then record all 4. Look at the meters and record the meter levels in a spreadsheet. rotate the bar and repeat the readings, then keep doing this for the 180 degrees. I then thought that I'd filter the pink noise to produce a fairly wide range of more focussed noise - so remove all bar 63Hz, then 250, then upwards to the top. Do the spin and record the levels for all this and then plot the results on a graph. The results were quite informative and not quite what I expected. It was easy to see the slope on the graphs - as the mic went off axis, the longer mics rapidly reduced in level. The shorter ones were far less sharp on the angle changes in level. What got me was the Sennheiser 416 - the sort of standard 'go to' shotgun mic is not really much of a shotgun at all at the middle-ish speech frequencies. It's drop-off was quite gentle. It has a neutral tone and I wonder if the popularity is simply because it's forgiving. The longer shotguns clearly need much more careful aiming.
With our music recording, I wonder why we rarely do multiple frequency response plots? We compare X against Y and never think about the changes that happen as you go off-axis? I wonder if our liking for certain mics on say guitars or pianos might well be because they change their response with angle more than we think? Point a mic at the neck joint gives more HF we know, but if the directivity at the bass end means the sound hole is covered too that might sound good. Point another with less off-axis bass response and we might discover this is less nice. Looking back at old mic posts - we constantly just talk about one frequency response plot. AKG and Neumann sometimes do their plots on a circular graph and reveal different frequencies, but they're quite rare.
With our music recording, I wonder why we rarely do multiple frequency response plots? We compare X against Y and never think about the changes that happen as you go off-axis? I wonder if our liking for certain mics on say guitars or pianos might well be because they change their response with angle more than we think? Point a mic at the neck joint gives more HF we know, but if the directivity at the bass end means the sound hole is covered too that might sound good. Point another with less off-axis bass response and we might discover this is less nice. Looking back at old mic posts - we constantly just talk about one frequency response plot. AKG and Neumann sometimes do their plots on a circular graph and reveal different frequencies, but they're quite rare.