|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
74.74.162.231
What is the neutral ("flat") frequency response if both L and R are played in room?If my target is flat response on pink noise from each channel, is my target still flat response from both channels?
Or is there some rules when L and R are combined (some kind of sloped target curve)?
P.S. : You do not need to post merely to teach that in-room response cannot be ruler flat
Edits: 06/19/16 06/19/16 06/19/16Follow Ups:
Dave,
Not sure if this is what you're referring to, but:
When playing a test signal through both channels simultaneously and measuring with a single microphone, it is common to see some cancellation effects at high frequencies. Because the wavelengths are so short (1.35 inches at 10KHz), it is easy for the signals from L & R speakers to arrive out of phase in the top octave. You can minimize the cancellation by measuring the distance from the microphone to each tweeter and moving the microphone such that the distances are equal to within 1/4 inch, and also make sure toe-in is the same. Or you can ignore it. It's an artifact of a single point microphone measurement and isn't representative of what you hear with two ears.
Regards,
Dave
What I see in my room is that as the mic is moved the cancelations ripple through the mids and highs. What I also find is that the couch impact my response more than room or speakers. My speakers are positioned to do well without EQ.
Just as in commercial theater seating - EQ'ing a room is an attempt to improve the imaging and performance of a front of Hall listening system. Using pink noise assess not only direct but also the reverberant energy in the room. Cinemas us what is called the "X-Curve" as a targeted response. The X-Curve is flat to 2kHz - then falls at 3dB/Octave above that to 10kHz. This curve is designed to account for the typical acoustics and absorption in cinemas.
Note: in the attached article, this actually results in Boosting the high frequencies of the direct sound in a large theater (Fig 3)
I think this is a little too aggressive a slope - I use a 2dB/Octave slope in my home theater/main listening system that cuts in at 3000 Hz. Because the room area is relatively small - but because I also us some diffusers - the surface area of the room is large enough to accommodate a little more high frequency. Also when I measure Live music in small performance venues (bars and small clubs) the music is alway fairly bright - and many/most studio recordings are not.
With my main system MMG's - which are fairly flat and have a bit of a rising direct response in the high frequencies I don'r really need too much EQ on the pink noise signal.
I send pink noise to left and pink noise to the right EQ'ing each speaker separately, then, using 250-4kHz band limited pink noise match the levels of the left to right to within 0.1dB.
"The hardest thing of all is to find a black cat in a dark room, especially if there is no cat" - Confucius
If you EQ for flat response, you will probably find that the high frequencies are too bright. There are different ideas on this. One curve shows most natural sound comes from a -3db per decade above 200 hz is best (-3 at 2k, -6 at 20k). This is supposed to recreate the sound in a concert hall. I would recommend a bit of experimentation.
Post a Followup:
FAQ |
Post a Message! |
Forgot Password? |
|
||||||||||||||
|
This post is made possible by the generous support of people like you and our sponsors: