QuestionQUESTION: Hi Brian, I'm stumped!!! I have an audiopipe AP-2002, and a LANZAR vibe 256 amp. my questions to you are, which amplifier would power an mtx thunder 8000 12" svc 8 ohm sub better? And what would the final ohm load be if I bridge either amp (which are both 2 channel) to power that one sub? I have seen diagrams, read instructions on wiring for certain ohm loads, and frankly my head is spinning. the lanzar amp is 2 ohm stable, I'm not sure about the audiopipe, i think it is though. The thing I'm worried about is either melting the amp or the sub, because one site I read, said it wouldn't safe to bridge a 2 channel amp to one 8 ohm svc sub due to the fact the amp would be running under it's recommended ohm impedence or something. PLEEEEAAASSSSEEE HELP MEEEEEE!!!!!!!! THANK YOU VERY MUCH FOR YOUR TIME AND EXPERTISE, ANY HELP WILL BE MUCH APPRECIATED!!!!
ANSWER: Hi Jesse,
I'll see if I can simplify things a bit for you.
First of all, an 8-ohm sub is always an 8-ohm sub, no matter how it's wired to the amplifier. Impedance is a property of the subwoofer, and it doesn't change. You can combine subwoofers or voice coils in various ways, and that will affect the final impedance load at the amplifier; but each sub's individual impedance will remain unchanged. If you just have one 8-ohm, single voice coil subwoofer, then it's very simple: your impedance will always be 8 ohms.
Every amplifier has a minimum impedance rating. As you reduce the load impedance, you'll usually increase the amp's power output; but at some point the amplifier won't be able to safely handle the extra current. "Bridging" an amplifier generates more current too; so the minimum impedance for a bridged amplifier is usually higher than the minimum impedance for the same amplifier in 2-channel mode. Usually, an amp that can tolerate a 2-ohm load in 2-channel mode won't be able to handle a load impedance below 4 ohms in bridged mode. Some car audio people explain this by saying that the amplifier "sees" half the impedance when it's bridged; but as you're finding, this can be needlessly confusing.
Generally, you won't hurt an amplifier by using a subwoofer that's a higher impedance than the minimum. For example, an amplifier that's 2-ohm stable won't have any problem running with a 4-ohm load; in fact, the amplifier will run cooler and produce less distortion. The trade-off is that it will also produce less power. Higher impedances don't hurt anything except power output; lower impedances will put more stress on the amplifier, but generate higher power.
So let's look at the specs of your two amps:
The Audiopipe amplifier is rated for 125 watts per channel into 2 ohms in 2-channel mode, or 300 watts into a single 4-ohm load when bridged.
The Lanzar amplifier's rating is 200 watts per channel into 2 ohms in 2-channel mode, or 400 watts into 4 ohms bridged.
You have a single 8-ohm subwoofer, so in either case you'd want to use the amplifier in bridged mode. Don't worry about the 8-ohm rating; you're well above either amp's minimum bridged impedance of 4 ohms. Generally, if you use an 8-ohm sub with an amplifier, you'll get about half the rated 4-ohm power; so the Audiopipe amplifier should be able to produce 150 watts, and the Lanzar amp could produce 200 watts. Your sub's designed for a power range between 75-400 watts, so either amplifier would work; but the Lanzar amp would give you more power (assuming the published power ratings are accurate).
If you had a second 8-ohm subwoofer, you could wire them in parallel, producing a combined impedance of 4 ohms. That's exactly what 8-ohm subs are made for; they're meant to be used in pairs with amplifiers designed to drive 4-ohm loads. In this case, the amplifier's output would be divided between the two subs. However, you won't hurt anything by using an 8-ohm sub by itself; you just won't get the full rated power from the amplifier. It's not harmful for either the subwoofer or the amp.
Hope this helps!
Brian
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QUESTION: Wow, now that was fast!!!! I don't even get an answer that fast over the phone!!! Thank you, that helped clear things a bit. I was just wondering, my lanzar amp's owner's manual has a bunch of wiring diagrams in it, I haven't paid that much attention to it, but I skimmed through it once and I thought it's most powerful state was bridged at 2 ohms or something like that. It says it's a 1600 watt amp but i guess that isn't always the case, like the audiopipe says it's a 1000 watt and according to the owners manual for that, it doesn't even push half of that. Anyways, so even if I get another amp thats more in the range of the subs rms, if need be, I can power that same said sub with a 2 ohm load and have no worries? THANKS AGAIN, YOU'VE BEEN MOST HELPFUL!
ANSWER: Hi Jesse,
To be honest, I'm not usually that quick with the answers--you just caught me at a good time.
I looked over the Lanzar amp owner's manual downloaded from their web site. Keep in mind that they use the same manual for several different amp models, so many of the diagrams don't apply to the Vibe256. However, from what I can tell, you'll need to stick with an impedance of 4 ohms or above when you're bridging the amp.
Your current sub can't be hooked up to any amp at 2 ohms--it's an 8-ohm sub, and it will be an 8-ohm load for any amplifier that you use with it. You won't often find 8-ohm power ratings in car audio amplifiers; the standard for car amps is 4 ohms or 2 ohms. If you had the 4-ohm version of your subwoofer, then the Lanzar amp's 4-ohm power output would be the same as the sub's maximum RMS power rating. If you want to get 400 watts to your 8-ohm sub, though, you'd need to find an amplifier that's capable of producing close to 800 watts into a 4-ohm load. There aren't many amps with that kind of power.
Note that most amp manufacturers will publish a "Peak" or "Max" power rating, and an RMS power rating. Usually, the peak rating is just for marketing; the only way to compare amplifiers is to look at the RMS numbers. In many cases, this means you'll need to look at the owner's manual. Some amplifier manufacturers make it very difficult to find the RMS ratings, and these tend to be the same manufacturers that publish wildly inflated "peak" ratings.
Personally, I'd go ahead and try the Lanzar amp with your subwoofer, and see what you get. There's nothing wrong with using a 200-watt amplifier with a 400-watt sub. If it gets loud enough for your needs, great; if not, you can shop for a more powerful amp--or a 4-ohm subwoofer.
Hope this helps!
Brian
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QUESTION: Yes, it helps very much! thank you! Sorry to bother you yet again, I'll make it short. Is it possible for me to run the 8 ohm sub with another sub that's 4 ohm. From the way I understood what you told me, it can't be done, but I just want to be sure. THANKS AGAIN, YOU GUYS ARE AWESOME!!!!
AnswerHi,
It can be done, but there are some serious disadvantages to mixing subs like this.
You wouldn't be able to bridge either of your current amplifiers if you had them connected to a mixed pair. When you wire a 4-ohm and 8-ohm sub in parallel, you end up with a combined impedance of 2.67 ohms. Both of your amps require a 4-ohm or higher impedance in bridged mode.
You could wire one sub to each channel, and use the amp in 2-channel mode; but you'd end up with less total power output that you'd get with a single sub. With the Lanzar amp, the 4-ohm sub would get about 100 watts on one channel, and the 8-ohm sub would get slightly more than half that on the other channel, for a total power output of around 150-170 watts. Compare this to the 200+ watts you'd get from the bridged Lanzar amplifier, using the 8-ohm sub alone.
If you bought a mono amplifier, you could combine both subs to the same output. Just about all mono amps are capable of load impedances down to 2 ohms. However, even connected to the same output channel, the two subs would use different amounts of power. This is because each sub retains its individual impedance. No matter how you wired them, the 4-ohm sub would get twice as much power as the 8-ohm sub when connected to a single amplifier output channel. When you're using multiple subs, you want their output levels to be as close to identical as possible.
Another option would be to use both your current amplifiers to drive the subs. You could use the Audiopipe amplifier for the 4-ohm sub, and the Lanzar amplifier for the 8-ohm sub (both amps could be bridged). This would allow you to carefully adjust the amplifiers to match the output levels.
Personally, I think your best option--if the single subwoofer doesn't meet your needs--would be to look for another 8-ohm sub to match the one you have. This would effectively double your output, as both subs could be wired to the Lanzar amp in bridged mode, resulting in a 400-watt output instead of 200 watts. Individually, each sub would still be using 200 watts, but your total power would be higher, as would your volume level.
Hope this helps!
Brian
