Uncategorized admin on 06 Nov 2002 02:10 am
iReTune
The cure for your deviated spectrum.
A couple of days ago I was particularly unhappy with my computer speakers so I decided to have a go at some acoustical calibration.
I snagged some pink noise and set it loopin’ in iTunes. Using the built-in mic on the TiBook and the real-time spectrum analyzer in Amadeus II I was able to visualize the offending frequency response curve for my speakers. I used the 10-band EQ in iTunes to flatten out each band as much as possible — because, surprise, the curve wasn’t anywhere near flat to begin with.
Now, of course, the mic built-in to a laptop computer isn’t the ideal microphone to be using for audio calibration, but it was all I had and it worked out fairly well.
This raises the question: How does one calibrate a microphone without having a calibrated speaker, and vice-versa? I assume the answer involves an oscilloscope and a tone generator. I don’t have any of that stuff so I’ll just make do.
The speakers sound much better now, but they’re still not quite right because, no doubt, some of the frequencies are off since the calibration involved a 10 cent microphone. The end result still is pretty nifty though considering the very small amount of effort involved.
Now I have a baseline EQ setting for those speakers on that Mac. The next step is to combine that waveform with the other EQ presets in iTunes so I end up with usable presets that take the evilness of the speakers into account.
Unfortunately, the data for the EQ settings looks a lot like 20k of this:
AAAAAAAAAAAAADQBWAG8AYwBhAGwAIABCAG8AbwBzAHQAZQByAAAA
Some decoding will be necessary, it seems.
Alternately, I could use Audio Hijack to add another 10-band EQ into the mix (as it were), thus providing some global equalization; which may or may not work — iTunes already has some problems with distortion because of the software EQ. Other options would be to buy some good speakers in the first place, or run the output through a real stereo with a big honkin’ parametric eq.
The only preset I ever use though is “Rock,” so I’ll just tweak that one by hand and see how it goes.
Here’s some fun stuff if you want to get really carried away.
3 Responses to “iReTune”
on 06 Nov 2002 at 6:28 pm 1.Cavedog said …
If you’re looking for boss computer speakers, check out either the Klipsch 5.1 thx - certified ( a little pricey) or the bargain thx Logitech Z560 4.1 speakers - which are on sale for $170 bucks quite often. I can’t leave Best Buy w/o taking a listen to both. I can only imagine how sweet a rocket launcher would sound with these babies! Someday I’ll work up the courage to come home with a set after work.
-e
on 06 Nov 2002 at 11:11 pm 2.MostlyHarmless said …
I’ll probably be spending hundreds of dollars on fixing the TV so I think I’ll skip the new computer speakers for the moment.
If I wanted to run the audio through a real stereo I have three receivers and nine speakers to choose from. I can’t crank it up in the apartment though — gotta buy a house and build one of those $100,000 listening rooms.
on 14 Dec 2002 at 1:51 pm 3.Pat Kraft said …
I like the Logitech’s. You can actually get them for about $110 now. Check pricegrabber. I picked ‘em up for $110, and amazon has them for $115 after a rebate.
Also, I love Audio Hijack, I use it all the time! Adding an EQ to DVD Player is hot.