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Old 29th October 2018
  #6
Lives for gear
 

Quote:
Originally Posted by Thavma View Post
...I have a dip at 1KHz with Adam A5Xmonitors, I have measured them separately but there is no dip, they only have dip when they both play in the sweet spot.
....
Could anyone help me to identify the problem....
Arrrgghhh!

My instincts told me to run from this question, but in fact, I had a discussion about this very issue (different frequency) with my Adam A7X speakers in my well-treated studio. With that emotional baggage revealed, here's what I learned:

Your chart doesn't show *how much* of a dip is being experienced, but as things go, let's simply assume (ugh) that what you're seeing/measuring is destructive interference between two sources that are being measured at one point in a 3D space.

A 1kHz wave in the air is about 34cm (13.4 inches) long. Therefore two 1kHz waves that arrive offset by 1/2 that length (17cm, 6.7in) will have a +peak/-peak confluence and show a reduction in the net level as a result. That maximum difference is about 1/2 millisecond offset in arrival time. That's also about the distance and arrival time difference between your ears!

Just with that information, any arrival differences between the two speaker sources at 1kHz that are in increments of 0.5ms, 1.5ms, 2.5ms, etc., will theoretically subtract from one another. Increments of 1.0ms, 2.0ms, 3.0ms, etc., will theoretically constructively add as coherent sources and add their power together.

The "theoretically" weasel word is in there because in the context of music in a real-world room, we're experiencing reflections of complex waveshapes from the walls, ceiling, table/console, and floor, arriving at different angles, different times and varying strengths; in addition to the direct nearfield signals coming to our two ears, all to be managed and interpreted by the incredibly refined audio signal processing wetware in our brains.

A variety of lessons learned have been documented by moving a measurement microphone by 2 inches and seeing the rather drastic differences that are captured by that small physical offset. It serves as a cautionary tale for those who shift their office chair and make recursive EQ decisions... but I digress.

One of the many bottom lines of what I'm offering to you is to simply ensure that you've done the due diligence of managing the most egregious reflections in your listening position, and then dial in your perceptive compensations to ensure that your mix decisions translate to the outside world of earbuds, cars, and the Grammy Awards' satellite feed.