maltesechicken

Bridged is different than running stereo. When the amp is bridged, the processing sectio nmakes sure that the output is matched because it is one channel. But when the amp is in stereo, there is no guarantee. I know of some songs where the kick drum jumps back and forth between L and R and that would really goof up a sub if each coil was on a different channel. As you noted, a 95% effective way around this is to put a Y splitter on it so the amp gets the same signal in L & R. This SHOULD keep the channels matched, but there is no guarantee, because in stereo, that channel only relies on itself. Now if the amp has an incredible processing section there should be no problems, but that's not likely in a run of the mill Kenwood.

going back to your obersvation about bridging. That is correct - one channel takes the + while the other the -. Yet, in this set up the channels are endlessly dependant on each other. The + can't produce more + than the - can receive. Running in stereo (even though its the same set of transistors) there is no dependancy on eachother. In theory, the Left could completely shut down and the right would keep on truckin because of their indepdance (although this wouldn't happen as if anything so major would happen to shut down a whole channel, the amp would go into protect mode).

I wanted to do this myself and was given a similar explanation as this from an installer in my local shop. He said "If you are using a Y it should work but there is no guarantee that it will be perfectly matched (for the reasons I mentioned above)." He then told me that if I wanted to do it, I should connect everything, and run a 50 hz test tone (with subs connected so the amp sees a load), and constantly test the output voltages. If they are anything BUT exactly the same, it shouldn't be done. High end amps will be more likely than mid-level amps to be dead accurate.

lpchouinard

I am sorry for the bad advice

recap
It's possible but he need test both channels with a DMM and if there's no difference (not likely) then this will work (and only if the input is mono).

Other solution
If he decided to run the amp in bridge mode, when adjusting the gain he should look for 30vac MAX, the amp should not go into protect if he's just 1 ohm lower than the recommended load. Also he will be better to use a test tone at -6db (50Hz) the expected output should be at 15vac, this way it will put less stress on the amp and is ears

n-sanity

Thanks for all the good advice!

I meant exactly what maltese chicken explained... although the amp is one, both channels are separate and act as dual mono-amps. I'm pretty sure processing is central though ... This is what i meant by the coils being ripped apart - if the signal going in isn't identical, they work against each other. If there's an error in processing or it's out of phase somehow ... that'd be a disaster.

As for testing with a 50hz tone, i always test all my speakers first at a -3db 440, then 220, 110, 60 and 35, unless im testing tweeters for functionality and response.

Now as for testing voltages... if anyone knows of a real-time multimeter under $100, please let me know, as mine will take around 3 seconds to settle on a number (during which it wildly jumps all over the place).

Once again, thank you very much for the advice! This run-of-the-mill kenwood was actually $300 when new, and the one i was about to get sold around 3 hrs before my arranged pickup meeting with the douche selling it. So alles gut

If anyone has a ~300w rms amp to run this sub, and is in the GTA, throw me an offer, my budget is flexible!