posted
-We know that electrical impedance of a woofer change with frequency. -Everybody should play the tone that hit highest SPL. -Now if i have 6 woofer with nominal impedance of 6 ohms each and i wire all them in parallel... I'll get 1 ohm nominal noh? -But if the best tone for better SPL is 57Hz The impedance of the total woofer should increase (change from 1 to X ohms ) ?
I have two RF Bd1000.1 'supposed' to support 1 ohms. I want to bridge these two amp to get more voltage and get output impedance of 2 ohms and get max power.
-The nominal impedance of woofer is now 1 ohms, but we want to put the bridged amp to the six parallel woofer. I KNOW THAT WITH THIS METHOD EACH WILL DRIVE .5 OHM , but i think that this is only at nominal impedance?!... If i want to play only the 57Hz tone with this system, and that i measure a total impedance of 2 ohms and up, That will be ok ??????
-Does anyboby wire there subs considering the only impedance of played tone ??(say in parallel..) ????????
NEED OPINION !!!!!!!!!
------------------ Show me the bass !
Posts: 643 | From: Quebec city | Registered: Mar 2000
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posted
Your best bet is just to measure the impedance while playing with a less extreme setup and use that to find the actual impedance that you will be looking at.
Colin
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posted
I found a site explaining how to measure the impedance of a driver at a given freq, (but I lost it) I did post a link to it on this forum but I can't find it. I printed the page and it has the url I'll do my best to find it, as it gives some VERY helpful results. My DD 9515 2/2 has an impedance of a hair over 7ohms per coil (nominal 2 ohm/coil) at 50hz so something like a 2000x or 4000x would be perfect with the coils paralleled.. so my memphis 1000d at roughly 3.5 ohms is nowhere near max power (but I bet it's very efficient at that load or email me and I'll give you a quick how to, it's very simple, you just need an rms ac voltmeter, dummy load (resistor) very close to the nominal resistance of your woofers for calibrating, a function generator (winisd on a computer works fine for that) a 500 ohm resistor (1 watt is best) and that's about it..
------------------ Digital Designs 9515b -- Memphis 1000D -- Panasonic source -- MB Quart fronts -- ADS power plate -- RW Audio LD4.12MBR -- 149.3 & climbing -- rwaudio.com -- Member of Team Hertz Canada -- robin@rwaudio.com
Posts: 735 | From: Calgary AB | Registered: Oct 1999
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I appreciate your advice, but i already know the method to measure the impedance of a woofer... I just need to know if someone here consider the impedance of the woofer only at played freq tone when plugging it to their amplifier... to keep the output current highest as possible... because if the impedance of each woofer rise say ...at 20 ohms when playing the best freq, the power will be very low... You know what i mean?
------------------ Show me the bass !
Posts: 643 | From: Quebec city | Registered: Mar 2000
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posted
if your measured impedance at that frequency is high enough then your amp should be fine. i have been told tho, that the amp may not like the DC resistance when it is first turned on...IOW, some amps won't even turn on due to the too low impedance at startup. i could be wrong tho...mr. dank told me about the DC resistance thing, at least i think it was him. one of the smart EE's around here.....
------------------ Team "Under Pressure"--now in Minnesota for the summer with the stroke of a cone, i can make you moan wall w/two shocker15's and a cadence a7hc, soon to be 2 class D's
posted
yeah i know of a very loud person that is suposedly doin this..he has amps the run at 4ohms but there wired to 1ohm becouse wehn it burps..i think his ohms go upp to like 5 ohms......this is what i heard...im not positive..but i am doin my new set up like this
------------------ well im not really a magician but sure as hell tryin and learnin to be.
posted
I ran my 2000x's at 1 ohm bridged instead of 4ohms. Actual impedance was about 2.5ohms and the amp would shut off some times. That might have been do to my voltage droping close to 10V.
------------------ 2-DD 9512's 2-2000X's (for now) 8.0ft^3 box in a civic trunk One big ass port ?????dB's
It's not the size of your woofer, It's the size of the waves your woofer makes!
Posts: 1259 | From: Fullerton. CA ,USA | Registered: Oct 1999
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