posted
couldn't you do that w/ a laptop, and a multimeter that has computer capabilities? i know my multimeter does.. i just have to hook it up to my computer and i can do graphs and such...... but that thing is neat however..
------------------ I respect any sub that can make me pass out.
posted
That seems cool but there's more to it than just building the device. This is from the site "Other Things You Will Need
Now that you've got the impedance analyzer all finished, it's time to learn how to use it. I won't go into any theory on how this thing works, because you don't really need to know. It's more important to know how to make it work and give you accurate readings. You will need along with your brand new impedance analyzer the following items:
Frequency Generator
Frequency Counter
Amplifier
Digital Voltmeter
Your speaker
Some wires " If you have a Linear-X meter, the PCRTA or the RTAjr, both will do in box impedence. the PCRTA will do alot more than the RTAjr though.
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Terry Shores Team STREET SOUNDS MECA M5 World Record Holder 154db MECA M5 Tn Record Holder 155.3db DB DRAG Certified SPL SSNW 157.5db so far.......
i see you know the page...i just got bored and did some surfin. was lookin for good tech pages on enclosure building but didn't find any that said much more than i already knew. anyone know of any?
------------------ Team "Under Pressure"--now in Minnesota for the summer wall w/three shocker15's and a cadence a7hc...in a tiny corolla
posted
If you're low on equipment, you can calculate impedance the long manual way by purchasing a high power 10 ohm resistor. all you need is a sine wave generator(or oscillator) and a multimeter.
using the resistor in series witht he speaker you measure the voltage across the resistor as well as the speaker for each frequency. The formula for speaker impedance is speaker impedance = VS(across speaker) / VR(across resistor) * 10(or the resistance of the resistor.
it's good for getting decent results with a minimum of a computer, multimeter, resistor and the stereo equipment(amp, subs)
whenever testing a speaker in free-air, try to hang the speaker from the ceiling if possible or put it on the least reflective surface you can find.
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Posts: 768 | From: Ottawa, On, Canada | Registered: May 2000
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posted
Following up on emu's post, yeah, be sure to do speaker measurements in a truly free-air environment (i.e. hanging subwoofer from a clothes line outdoors). I once tested an 18" sub's T/S params in a large dorm hallway and then again outdoors...the difference was something like 20%. Maybe smaller subs wouldn't be affected as much, but still...
------------------ "The supreme misfortune is when theory outstrips performance" - da Vinci
Posts: 95 | From: PA then IL then TX | Registered: Oct 1999
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posted
my neighbors would really think im crazy hanging a sub out on the clothes line, lol, j/k guys, i know you gotta do what has to be done to do stuff right sometimes
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