I have just bought a 10" MB Quart Subwoofer (Great Deal). This is a 6 ohm sub. How will this work with a 4 ohm rated power amp. Will the amp deliver the same ammount of power, but run cooler/hotter? Will the amp deliver less power as a result of "seeing" more impedance? (remember V=IR???!!!). Thanks for any help.
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Mike 92 XLT
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Yes, the amp will deliver less power as a result of the higher impedance. However, I'll bet that sub is a dual-voicecoil speaker, right? If that's the case, simply wire the two voicecoils in parallel and then the amp will see a three ohm load and deliver more power, assuming it's stable below four ohms (most newer amps are stable to two ohms). That's what I'm doing with my system: one JL Audio six ohm dual voicecoil speaker wired in parallel.
peace
Mike
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Mike
JTang
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You're referring to the MB Quart SBR 250.92? I think that one's strictly a 6 ohm single voice coil sub, I could be wrong though. On a single channel, whatever your amp is rated at 4 ohms, knock that rating down to 75% and that's about what you're going to get (if it's a single voice coil). Your amp is going to run a bit cooler.
If you're going to power the sub by bridging your amp, (if it is only a single voice coil 6 ohm sub) then each channel will see a 3 ohm load, so as long as each channel can handle at least a two ohm load, you should be fine. Again, take the bridged wattage, of 4 ohms normally, and knock it down to 75%. Really, however, that sub only takes about 175 watts maximum, so don't overpower it. The RMS is what you should be trying to match on both, not the peak power.
If you're going to power the sub by bridging your amp, (if it is only a single voice coil 6 ohm sub) then each channel will see a 3 ohm load, so as long as each channel can handle at least a two ohm load, you should be fine. Again, take the bridged wattage, of 4 ohms normally, and knock it down to 75%. Really, however, that sub only takes about 175 watts maximum, so don't overpower it. The RMS is what you should be trying to match on both, not the peak power.
JTang & MIke 92, thanks for the information. That is the sub I have, and it is a single voice coil. The amp I have is 2 ohm stable, and will run at 180 watts max power bridged (4 ohms). The Max power on the sub is 175, so 75% of 180 should keep me in a safe range (closer to RMS).
Another Question. If I bridge the amp and run a single sub (6 ohms), the impedance seen is 3 ohms? Then, if I decide to run 2 of these subs, in parallel, on the bridged amp, will the load seen by each channel be 1.5 amps? In which case, the impedance is too low for a 2ohm stable amp, causing the amp to run hot and possibly burn out.
Thanks again for all of your help.
Matt.
Another Question. If I bridge the amp and run a single sub (6 ohms), the impedance seen is 3 ohms? Then, if I decide to run 2 of these subs, in parallel, on the bridged amp, will the load seen by each channel be 1.5 amps? In which case, the impedance is too low for a 2ohm stable amp, causing the amp to run hot and possibly burn out.
Thanks again for all of your help.
Matt.
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