Home Theater Forum and Systems banner

First time REW Plot

Tags
plot time
18K views 39 replies 7 participants last post by  eyleron 
#1 ·
Hello everyone, I just made my first plot using REW. I am kind of thinking that something must be wrong with the way I am measuring, and maybe some of the more experienced members of this forum can help me out. I just wanted to get familiar with the software, before I started measuring my home theater. I have a set of M-Audio studio monitor's that are connected to my PC that I measured. This plot just looked a little to good to me, but I have always loved these speakers. Just to make sure that everything was working right, I cut the mid's on my soundcard EQ, and sure enough the plot showed exactly what I did. So anyway here is my first plot, could anyone tell me why this might look just a little too good to be true?
 

Attachments

See less See more
1
#35 ·
I measured the flat curve also when I set up for the others. It too seemed a bit to reserved for me on the high end. The "flat" curve seemed to be the curve where no EQ was applied at all (see above post), as in the most flat through 20kHz. This is also what I noticed during critical listening, that the cymbals and high end were not natural to me. The measurements I obtained do seem a bit counter intuitive, because I have a highly reflective room. Below is the FR for the Audyssey "flat" curve:
 

Attachments

#37 ·
See how 60Hz and 120Hz (I think) look flat, not decaying across time? That's an indication that this is power noise, probably from the computer, being driven through the soundcard and into the system. If it's from the computer, it's not real and you don't need to worry about it. If you are on a laptop and can successfully take measurements while running off battery, you will probably see these disappear and then you will have confirmed that they are measurement anomalies.

Does your USB soundcard have its own power supply? If so, the battery in the laptop might not make any difference, you may be stuck with the power noise isolation, or lack thereof, from the USB device.

Bill
 
#38 ·
Yeah I will try it from the laptop, but that is a little disturbing considering I bought an Antec Signature power supply when I bought my PC. The USB sound card is powered by the USB itself, not a dedicated power supply. I never thought of associating that frequency with power operating at 60Hz though, good call!
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top