Impedence?

Okay so I went to my JL dealer today to check on my VR-series speaker repair and see what they had in the way of comps and what-not.. when I get into a conversation with one of the sales guys he explains to me.. I guess.. that 2 woofers need to be 8-ohm woofers to be wired to 2-ohms @ the amplifier. So I'm sort of confused, because, he really is quite insistent about this. So I tell him that as long as I've messed with cars, I've always wired 2 4-ohm subwoofers for a 2-ohm load on a monoblock. I mean, this is sort of one of the first thing I learned. Now, I'm aware that if you BRIDGE two channels, say off an A/B amp, the amp will see half-of what the speakers are wired at, but the monoblock? Wouldn't this ruin the "monoblock" purpose? So the guy starts walking around the store talking about "how long he's done this" and then dares me to prove him wrong. "Okay" I think, and I pointed his dandy computer right at sounddomain.com and opened that handle little "Subwoofer Wiring Guide Selector" and sure enough, two 4 ohm speakers is wired at any given monoblock for a 2-ohm load. Not So! Claims this guy, then he starts telling me how the guide is totally wrong and it is because Circuit City and Best Buy control the industry and Rockford had to change its lines all around and thats why everyone thinks that two 4-ohm speakers in parallel wire to 2-ohms when it really wires to 1-ohm. Can anyone tell me what this guy was talking about?"I'm finished!" - Daniel Plainview

Hes wrong, if two 4 ohm resistors are wired in parallel, the resistance in the circuit is 2 ohms. I dont know what that guy is trying to tell you, but cc and best buy did no come up with or change ohms law.6th gen Celica | Alpine CDA-9827 | Pioneer GMX962 | CDT CL components | JBL 600.1 | Infinity Reference 12

I think that guy hit the crack pipe or bong a little bit too much. Best Buy and Circuit city have nothing to do with ANYTHING. Two four ohm loads wired in parallel will create a 2Ohm load.

Right Right but this guy was telling me that "internally" the amplifier is really operating at 1-ohm because all a monoblock is a bridged amp so its really at 1-ohm. He kept saying "amp sees half of what the box sees." Can you even guess at what he meant?"I'm finished!" - Daniel Plainview

good question...now i'm curious myself.  Is a monoblock amp the same as a bridged amp?  if so then wouldnt the 2 ohm load actually appear to be a 1 ohm load (assuming a monoblock is the same as a bridged amp)  but if it is the same then why put terminals for 2 subs ( 2- and 2+)  on a monoblock?  if a monoblock was a bridged amp then wouldnt there only be a need for 2 terminals (1- and 1+) or would both sets of terminals on the monoblock be bridged meaning u could hook up 2 sets of dual 4 ohm subs, each putting out a load of 1 or 2 ohms?  I'm confusing myself here now, but if a monoblock is the same as a bridged amp then why would they sell both?

Mono = one channel.  No relationship to a bridged stereo (2-channel) amp.  They are different animals.  Amplifiers don't "see" anything, they supply voltage and current into an impedence load.  If you connect a 2-ohm load to an amp, it operates into a 2-ohm load.  Poormanq45 had it right: too much crackpipe or bong action happening somewhere.Support the12volt.com

The guy is very confused. http://www.bcae1.com/bridging.htm Print that out and give it to him. He probably won't understand it. I'll try to give him the bridging for idiots explanation: First: Mono amplifiers aren't necessarily bridged amplifiers. Second: The box doesn't see anything. Tell the guy this statement makes him sound like an idiot. Third: The load the amplifier "sees" has nothing to do with what's in the stupid amplifier. It has everything to do with how the resistors (speakers) are wired together. Fourth: quote from bcae1.com, because this is the most important part: "If we take a single 4 ohm speaker and bridge it on that same amplifier, the amplifier will be able to apply twice the voltage across the speaker. This is because while one speaker terminal is being driven positive (towards the positive rail), the other terminal is being driven towards the negative rail. This will allow the entire power supply voltage to be applied to the speaker's voice coil. It will now be able to drive the 4 ohm speaker with 40 volts instead of 20 volts..." Fifth, and finally: another quote from that page, because I'm lazy: "The same amount of current flows through the output transistors whether the amplifier is driving a 4 ohm mono load or 2 ohm stereo load. As far as the amplifier is concerned, they are the same load. NOTE: Some people say that when an amplifier is bridged onto a 4 ohm load, it 'sees' a 2 ohm load. While it is true that the same current flows whether the amp is bridged on a 4 ohm load or a 2 ohm stereo load, the amplifier is driving a 4 ohm load across its outputs. A single 4 ohm speaker can never be a 2 ohm load." In other words: Just because the output transistors have the same amount of current running through them when bridged doesn't mean that the amplifier "sees" a different speaker load! The wiring guides all over the internet are correct and have nothing to do with Circuit City and Best Buy. The fact that he came up with some conspiracy theory like that to explain something he obviously doesn't understand ... is well, really freaking funny. You should laugh at him. New Project: 2003 Pathfinder

The guy used to wander up and down the street talking to himself and yelling at his imaginary demons...then he was tagged to sell subs.  Go figure.

or maybe the demons werent imaginary and its all a dastardly evil plan to have him corrupt the minds of all who want to know the TRUTH about audio.

lol, you never know.  ;-)New Project: 2003 Pathfinder