_basso_ said:
it's slight lack of high frequency, and i don't know if the angel is the problem. may be it's has something too do with the microphones ?
I doubt the angel was the problem. I haven't seen any of those since I was a kid. They're extinct, aren't they?
But seriously, when you said "the angle outward is ten degrees", did you mean each mic was angled 10 degrees out from the centre, implying a subtended angle of 20 degrees? Or did you mean that each microphone was only five degrees out from centre, creating a subtended angle of 10 degrees? Maybe it's not much of a difference anyway, but I'm just putting up possibilities.
I had a similar problem recording a pipe organ with DPA 4015s, which have a slight high frequency boost on axis. It was the first time I had used them, in fact. I had the 4015s angled apart like ORTF, and when I played it back later there was an obvious high frequency hole in the centre of the recording. I fixed it by converting the signal to MS, and EQing the M separately to the S until it sounded better. (These days I am smarter when using 4015s, and adjust the angle accordingly.)
So perhaps the omnis you were using have an on-axis high frequency boost, or a very poor off-axis response at high frequencies.
Or perhaps they are just a bit too far apart, causing the classic hole-in-the-middle effect, although it is only noticeable at high frequencies on this recording due to the increased directionality of high frequencies contrasted against the larger and less directional wavelengths of low frequencies.
