Jolbaru_LGT Posted November 11, 2022 Share Posted November 11, 2022 So, I have a stock under the seat sub. I thought it was a good idea, when I bought it, but as my system expands, I'm not so sure. Anyways, I also have an Alpine iLX-207 HU. When I adjust the crossovers to block the bass in the front and rear speakers, I'm also losing the bass that goes to the subwoofer. Now, I'm wondering if there's any way to access the sub output on the Alpine HU? Such as cutting off the speaker inputs going to the sub and replacing them with vampire taps from the Alpine's sub output, so I actually have some bass in the system. It's also worth noting that I'm planning on putting a sub in the back, but I'm just wondering if what I'm thinking is possible with the under the seat sub, before I remove it altogether. Thanks! Link to comment Share on other sites More sharing options...
blackobxt Posted November 12, 2022 Share Posted November 12, 2022 The under seat sub requires high level inputs (speaker outputs from stereo). When you adjust the crossover you are essentially removing the frequencies the crossover in the oem sub filters. Your only option might be to wire in crossovers in between the speakers and the head unit or just pony up and amp the speakers. Even on stock speakers, amping them is one of the first things I do Link to comment Share on other sites More sharing options...
Jolbaru_LGT Posted November 12, 2022 Author Share Posted November 12, 2022 2 hours ago, blackobxt said: The under seat sub requires high level inputs (speaker outputs from stereo). When you adjust the crossover you are essentially removing the frequencies the crossover in the oem sub filters. Your only option might be to wire in crossovers in between the speakers and the head unit or just pony up and amp the speakers. Even on stock speakers, amping them is one of the first things I do I have the KTP-445A Alpine in-line amp. I ran a separate power and ground for it, but kept the stock power and ground to just power up the under seat sub. Link to comment Share on other sites More sharing options...
blackobxt Posted November 12, 2022 Share Posted November 12, 2022 Are you running the KTP with the high level inputs or the rca low level inputs? Link to comment Share on other sites More sharing options...
blackobxt Posted November 12, 2022 Share Posted November 12, 2022 I’m assuming the high level since it’s the 445A and not the 445U Link to comment Share on other sites More sharing options...
Jolbaru_LGT Posted November 12, 2022 Author Share Posted November 12, 2022 31 minutes ago, blackobxt said: Are you running the KTP with the high level inputs or the rca low level inputs? It’s the high level inputs. The amp that’s specifically for Alpine HU’s and not the universal one. Link to comment Share on other sites More sharing options...
blackobxt Posted November 12, 2022 Share Posted November 12, 2022 You’re kind of out of luck with the oem sub then, unless you switch to the 445U. The 445U has a built in crossover via dip switches and adjustable front and rear gain settings 1 Link to comment Share on other sites More sharing options...
Jolbaru_LGT Posted November 12, 2022 Author Share Posted November 12, 2022 Lol... I can't vampire tap the speaker wires before they go into the HU and splice that in before it hits the sub? Link to comment Share on other sites More sharing options...
silverton Posted November 12, 2022 Share Posted November 12, 2022 It's not going to work how you want it to. The sub gets its inputs from the rear speakers and a built in crossover. You would need to replace the OE woofer with an aftermarket one to use the sub output of your HU. 1 Link to comment Share on other sites More sharing options...
blackobxt Posted November 12, 2022 Share Posted November 12, 2022 Or switch to the ktp445u and leave the crossover on the head unit alone Link to comment Share on other sites More sharing options...
AWDFTW Posted November 13, 2022 Share Posted November 13, 2022 If you're getting rid of your OEM underseat woofer and harness, I'll be happy to rehome it. 1 Link to comment Share on other sites More sharing options...
Jolbaru_LGT Posted November 13, 2022 Author Share Posted November 13, 2022 3 hours ago, AWDFTW said: If you're getting rid of your OEM underseat woofer and harness, I'll be happy to rehome it. I’ll let you know. I have to get this sub in the rear quarter panel working first. But if I do, I’m sure I won’t need it Link to comment Share on other sites More sharing options...
Jolbaru_LGT Posted November 13, 2022 Author Share Posted November 13, 2022 This might be for another thread, but does anyone know about the polarity of a stock 09 Outback HK 8” sub? Or a good way to find it? I’m pretty sure it’s dual voice coil @ 2 ohm. It’s got like, 4 posts.. I am at a loss on how to wire it. it’s being connect to an Alpine MRV-M250, a 250watt @ 2 ohm mono amp. I don’t believe it’s 1 ohm stable. any help or direction would be greatly appreciated. I know the speaker might be crap, but I want to get everything in and then decide if I’m going to upgrade it or not. It’s basically the bracket, HK sub, and cover that goes in the stock passenger rear quarter panel that replaces that little cubby. thanks! Link to comment Share on other sites More sharing options...
blackobxt Posted November 13, 2022 Share Posted November 13, 2022 Have you checked the impedance of each voice coil? I haven’t found and solid info on the oem sub. Link to comment Share on other sites More sharing options...
Jolbaru_LGT Posted November 13, 2022 Author Share Posted November 13, 2022 20 minutes ago, blackobxt said: Have you checked the impedance of each voice coil? I haven’t found and solid info on the oem sub. Sorry, I’m a noob on audio, how do I do that? Do you have a link to a decent video or tutorial? I do have an ohm meter, btw. Link to comment Share on other sites More sharing options...
Jolbaru_LGT Posted November 13, 2022 Author Share Posted November 13, 2022 (edited) Just trying to wrap my head around this: my amp is only stable down to 2 ohms. The speaker in question is 2 ohm dual voice coil. Meaning I should only connect 1 voice coil to keep it 2 ohm. Connecting both coils in parallel would result in 1 ohm? Edited November 13, 2022 by Jolbaru_LGT Link to comment Share on other sites More sharing options...
blackobxt Posted November 13, 2022 Share Posted November 13, 2022 You set your meter to ohms and put the leads on one voice coil then the next voice coil. Make sure nothing is pushing down on the woofer as it will affect your readings. If it’s a dual 2ohm you can either wire it to 1ohm or 4ohms. The problem with running it at 1ohm would be heat but that likely won’t be your issue, it will likely be overpowering that cheap paper sub even at 4ohms. You might get away with it but results will likely be less than desireable. 1 Link to comment Share on other sites More sharing options...
Jolbaru_LGT Posted November 13, 2022 Author Share Posted November 13, 2022 (edited) Ok, I see.. wiring in a series would net 4 ohms, taking the strain off of the sub. Ah…. Edited November 13, 2022 by Jolbaru_LGT Link to comment Share on other sites More sharing options...
blackobxt Posted November 13, 2022 Share Posted November 13, 2022 Taking the strain off the amplifier. You will get 150w rms at 4ohm and 250w rms at 2ohm and likely 350ish rms at 1ohm. Even at 150 rms that sub is going to be waaaaay overpowered. May or may not be an issue. Like I said, I always amp factory speakers before I go big and I’ve always had great results even running 75+rms to them and never blown one up but they are open air and don’t overheat but that little inefficient sub in its (I’m assuming) sealed enclosure might get pretty hot. Link to comment Share on other sites More sharing options...
blackobxt Posted November 13, 2022 Share Posted November 13, 2022 For clarification, I’m not trying to discourage you but I am trying to make you aware of your hurdles and potential results. I honestly think you should try it and report your results. Link to comment Share on other sites More sharing options...
Jolbaru_LGT Posted November 13, 2022 Author Share Posted November 13, 2022 (edited) 3 hours ago, blackobxt said: For clarification, I’m not trying to discourage you but I am trying to make you aware of your hurdles and potential results. I honestly think you should try it and report your results. I will! This is mainly about me wiring in the subwoofer system and getting everything in place. I wanted to go for a stock look, and not have some goofy sub enclosure hanging out in my trunk. So far I’m pretty happy with the way it’s progressing. I was disappointed at first with the HK speaker swap(which I believe was from a GT sedan) But as soon as I put in the Alpine KTP-445A(which is 2 ohm stable) and cut the lower frequencies, it came alive! Now if my theories are correct, and I get this 09 HK outback sub to work, it should really round everything out. Really all it needs is some bass, and possibly a pro audio tune. I think I did all right with the HU’s crossover but it could be better, and I didn’t even touch the time correction, lol. But definitely, an aftermarket sub is in order. I had the Pioneer TS-A2000LD2 in mind when I picked out the amp from eBay, so that’s what my thought is right now. But there’s also the Kenwood Excelon KFC-XW800F… Edited November 13, 2022 by Jolbaru_LGT Link to comment Share on other sites More sharing options...
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