Frequency response graph and EQ
Mar 5, 2015 at 6:18 AM Thread Starter Post #1 of 17

radosuaf

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I was wondering - if you have a frequency response graph of a certain speaker, can it be somehow used to set the EQ so that you get a more or less flat line?
I don't mean the fact that if you see a peak at 5 kHz for example you shall lower that setting @EQ but if the graphs do give the values that should be applied.
 
Mar 5, 2015 at 9:23 AM Post #2 of 17
It can certainly help. It just depends on how wide the freq band of each EQ slider is. The other thing to remember is that boosting/cutting frequencies can also change other parts of the sound outside the specific range of the EQ slider you just moved. Boosting uses more energy, and that leaves less energy for other high dynamic parts of the music. Reducing a peak frequency might reduce harmonics that were boosting other parts of the frequency range. Finally, "flat" does not always mean "good" - your specific ears might prefer a sound a that is not flat.
 
Mar 5, 2015 at 10:32 AM Post #3 of 17
How are you getting the frequency response graph? If you are using manufacturer supplied graphs or ones created by professional reviewers, those are often anechoic measurements to eliminate room interaction. How the speakers respond in your room could (and typically would) be a bit different because of how the sound reflects within your room. So people that use EQ to smooth the response take measurements from the listening position with a calibrated mic and/or SPL meter. REW is free software that many people use to then plot the frequency response and then retake the measurements as they apply EQ to see how it works: http://www.roomeqwizard.com/.

And to overcome the problem billybob_jcv described with graphical EQ, many people use PEQ as it allows for more finely correcting the speaker response.
 
Mar 5, 2015 at 10:40 AM Post #4 of 17
  I was wondering - if you have a frequency response graph of a certain speaker, can it be somehow used to set the EQ so that you get a more or less flat line?

 
To an extent yes, but note that your room unless it is professionally dealt with may have different room modes than what we can assume is likely an acoustically superior room where the measurements were taken. 
 
Mar 5, 2015 at 11:34 AM Post #5 of 17
LOL - I wasn't even thinking of the room - I missed "speaker" and assumed we were talking about headphones. So - yeah - everything I said, plus everything they said!

In a room, you really need to take your own measurements. Luckily, that's pretty darn easy to do using TrueRTA, RoomEQ Wizard, AudioTools and other software, an inexpensive mic and a calibration file for the mic. Parts Express has a cool & cheap mic that fits in your phone:
http://www.parts-express.com/dayton-audio-imm-6-calibrated-measurement-microphone-for-iphone-ipad-tablet-and-android--390-810
 
Mar 5, 2015 at 11:37 AM Post #6 of 17
LOL - I wasn't even thinking of the room - I missed "speaker" and assumed we were talking about headphones. So - yeah - everything I said, plus everything they said!

In a room, you really need to take your own measurements. Luckily, that's pretty darn easy to do using TrueRTA, RoomEQ Wizard, AudioTools and other software, an inexpensive mic and a calibration file for the mic. Parts Express has a cool & cheap mic that fits in your phone:
http://www.parts-express.com/dayton-audio-imm-6-calibrated-measurement-microphone-for-iphone-ipad-tablet-and-android--390-810


Hadn't seen that before. That's a nice device.

If you don't have Apple products, this USB mic is designed to work with measurement software: http://www.minidsp.com/products/acoustic-measurement/umik-1. In fact, I think REW has the calibration files for it already.
 
Mar 5, 2015 at 11:41 AM Post #7 of 17
To an extent yes, but note that your room unless it is professionally dealt with may have different room modes than what we can assume is likely an acoustically superior room where the measurements were taken. 


Or even outdoors instead of "an acoustically superior room." That's what Josh Ricci does with subwoofers: outdoor ground plane measurements.
http://www.data-bass.com/systems
 
Mar 5, 2015 at 11:44 AM Post #8 of 17
Many years ago when I set-up my PEQ for my subwoofer, I just used the standard cheap measurement system - TrueRTA, a RadioShack SPL meter and a calibration file that could be downloaded from the AVS forums. It worked well enough for my purposes, and I must say, it sounded FAR better than without the PEQ.
 
Mar 5, 2015 at 12:21 PM Post #9 of 17
I still remember the time when we used RTAs in cars, then USB mics came out, and we'd tape that mic to the headrest and sit in the back with the laptop. At around the same time integration processors with interfaces for Windows were coming out, but didn't really get that much traction here unlike the US since preserving the factory GPS (which wasn't popular here to begin with) was one of the primary reasons for not tearing out the factory electronics.
 
Mar 5, 2015 at 3:25 PM Post #10 of 17
Mar 5, 2015 at 4:48 PM Post #11 of 17
So, if we discuss, say, ~175 Hz and neutral setting (middle line), shall the EQ be set to more or less - 6 dB?


Try it and see. PEQ would be better than graphical EQ because you can adjust the Q of the response.


Can the calibration mic that is supplied with Onkyo amplituners (I own one) be used for the purpose?


You have to know the calibrations for the mic to use it. For example, scroll down here. It's the calibration corrections for the RS SPL meter billybob mentioned.
 
Mar 5, 2015 at 4:52 PM Post #12 of 17
Guess it would help if I include the link to the calibrations: http://forum.audiogon.com/cgi-bin/fr.pl?htech&983682086&openflup&1&4 :)
 
Mar 5, 2015 at 8:47 PM Post #14 of 17
I still remember the time when we used RTAs in cars, then USB mics came out, and we'd tape that mic to the headrest and sit in the back with the laptop. At around the same time integration processors with interfaces for Windows were coming out, but didn't really get that much traction here unlike the US since preserving the[COLOR=FF00AA] factory GPS (which wasn't popular here to begin with) [/COLOR]was one of the primary reasons for not tearing out the factory electronics.


You're on an island, how lost can you get?? :p


Just kidding! I know it's a pretty darn BIG island... :D
 
Mar 6, 2015 at 3:13 AM Post #15 of 17
You're on an island, how lost can you get??
tongue.gif



Just kidding! I know it's a pretty darn BIG island...
biggrin.gif

 
The problem here is that professional GPS systems (the ones that help you navigate with coordinates instead of colorful rendered maps) will work well, but the maps for the usual systems weren't completed until recently due to how this isn't exactly laid out like Manhattan or Tokyo (the old walled city was, but you can walk across that over lunch assuming you don't get heat stroke). Add to that how, until recently, traffic flow schemes were perpetually experimented with in congested areas that one of our main concerns was how quickly can they update the GPS data before I slam into oncoming traffic because this place is suddenly a one-way road going the other way. We were surprised actually that when they got implemented here they can even update that cops were up ahead, and it made me paranoid because the idiot I carpooled with going up the mountains was smoking weed the whole damn time (at that point I wasn't even sure if I was paranoid simply because I had the right to be, or because I inhaled too much second hand smoke that wasn't my Marlboros).
 
Funny thing is I've gotten out of many situations where I'm about to get lost just by looking at where the sun is 
tongue.gif
 What confuses me is that people look at me and say they're amazed at how I just did that. I can't believe this isn't common knowledge (was I the only one who joined the Scouts?!) but then there's our old-school version of On-Star, which is to open the window and ask a random stranger smoking on the sidewalk (preferably the kind wearing an office suit and coffee, and not the topless dude with a bottle of gin).
 

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