posted
I was talking to someone at work today who mentioned some of his former college buddies (geeks in the fullest sense of the word) had developed a program whereby you draw an arbitrary waveform and then draw a 2nd waveform. The program chugs away for about 5-6 hours and comes up with an exact circuit schematic that's needed to convert the first waveform into the 2nd. Supposedly it is very accurate.
Then I thought how cool this program would be if you could feed it the output of the frequency response curve of your system, and then the second curve you'd feed it is what you WANT the frequency response to be. If it could crank out a monster schematic for you to build, that would be the best thing since sliced bread. No more messing with an EQ or other stuff...just build the circuit and plug it in. Has anyone else heard of such programs? And how can it possibly work without even knowing the characteristics of the networks it is connecting to? This is absolutely fascinating.
-------------------- "The supreme misfortune is when theory outstrips performance" - da Vinci
posted
The program couldn't take into consideration the frequency effects of the car on your waveform, which are amplitude and phase dependant. Thats why experimentation works better than modeling in most cases (look up chaos theory, minute variable theory, etc)
ShadowStar
-------------------- You can't build a reputation for what you're GOING to do.. But you can build one for TALKING about it!
It's all about knowledge, love and respect.
Posts: 2578 | From: Somewhere In the Northeast | Registered: May 1999
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posted
I downloaded some free RTA software a while back.. You need a decent sound card, but nothing too special.
Plug a microphone into the back... the better quality mic, the better the response, but even a cheap mic should be good from like, 40Hz to 15Khz.
And when you play pink noise on your system, with the mic where your head normally is, it will take that relative response you want, so you can set your EQ. Or you can set your EQ and see how close you got, whatever. It works just like an RTA, Real Time Analyzer.
The software is free, decent mics aren't too expensive.
posted
the problem with stuff like this is the response can change dramatically as the voice coil heats up, the temperature changes, humidity, etc, All contribute and then you'd be left with a big expensive circuit that makes the sound worse. placing this in the line level stage would help, but then you can run into issues of overloading the pre amp circuits and creating instabilities/oscillations in your system. It is widely agreed that capacitors and inductors in the signal path should be minimized. As in all aspects of audio, careful consideration of driver selection and crossover design minimize the need for added equalization.
A big elaborate expensive circuit is more of a half assed attempt to cure symptoms instead of curing the real problem.
jt
Posts: 56 | From: atlanta | Registered: Nov 2000
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posted
You still would need to know the response of the speaker that you are calibrating the mic with. Maybe Im wrong, Im assuming the mics not perfectly flat are they?
[ 10-26-2001: Message edited by: Mr.Dank ]
Posts: 1259 | From: Fullerton. CA ,USA | Registered: Oct 1999
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posted
I'm not totally sure but I think mics are weighted to account for the human ear's transfer function (if you can call it that).
Posts: 3958 | From: State College, PA | Registered: Sep 2000
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posted
Yes, I thought I read somewhere that A-weighted mics acount for the fletcher and munson loudness curves fairly closely. But what I can't remember is what level they work best at, cause the curves change with increasing or decreasing loudness.
Posts: 3958 | From: State College, PA | Registered: Sep 2000
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