View Single Post
Old 28th October 2019
  #15
Lives for gear
 

Quote:
Originally Posted by Geoff Poulton View Post
What frequency would you aim for with that deedeeyeah? Or would it depend on.........?
yes, it depends...

short answer: the lf range as you experience the largest difference in level with the phase relationship off, the mids as there is simply the most 'traffic'/our ears are the most sensitive and the hf range which can make the stereofield more wide.

___


long answer: i mostly measure the room before i set up spaced mics and then decide on their spacing (although i hardly ever end up using spaced mics as mains but anyway):

let's assume you experience a 'room tone' at 100hz: you could almost cancel out this frequency by using a spacing of 83,5cm which would get you (up to) 90° degrees phase offset at 100hz while all other frequencies would have a less (or a less noticeable) phase offset.
then you set identical apf's on both tracks but invert phase on just one track until you get +90° one one side and -90° on the other side at the frequency which you want to cut down.
with multple apf's you can affect the phase relationship in multiple frequency areas - but also completly mess up things, so handle with care! :-)

i'm using a measurement mic, an fft to analyze and a speaker processors for precise alignment (and i record clave clicks right in front of the main mics). without fft, a goniometer and even a simple spl meter are also helpful (although way less precise).

___


p.s. i learned s few things from measuring and aligning large speaker systems and especially from designing and measuring subwoofer arrays: same principles on the way in as on the way out...

Last edited by deedeeyeah; 29th October 2019 at 12:34 AM.. Reason: edited twice for clarification and p.s. added