Sion Nnjs Stephens Posted August 18, 2017 Report Share Posted August 18, 2017 I'm not a pro in this area so please be patient. I recently had my sub installed at a shop in my area along with an amp and a lc7i. Whenever I crank the volume up I get this low rumbling sound from the sub. It makes this noise even when there is no bass in the music I'm listening to (i.e. intro, outro). However, it doesn't make this noise while the music is paused. When I looked in my trunk i noticed that they ran all of my signal cables with my power and ground, so I figure there's a ground issue. I went back to have it looked at and the guy told me that since my car is so small it will make that noise due to the amount of bass that I have, and if it was in the trunk of a small car instead of the back of an suv I wouldn't hear it. None of this sounds correct to me, am I correct in assuming that he was just being lazy? I also noticed that my bass knob does not turn my amp all the way off. When the knob is all the way down I can still hear my sub, just at a much lower volume. Is this normal? Oh yeah, due to my sub being a 2ohm and my amp not being 1ohm stable I am forced for now to operate at a 4ohm load. This is only pushing 750 watts to a sub that 1100 watts is recommended for. The instructions say that I can safely power it with 500-1200 watts rms. Could this be a contributing factor? 2009 BMW X3 single Kicker Comp Q 15 Kicker ZXS1500.1 Audiocontrol LC7i Kicker Comp Q 15 Kicker ZXS1500.1 Audiocontrol LC7i Link to comment Share on other sites More sharing options...
3vil Posted August 18, 2017 Report Share Posted August 18, 2017 Yeah, something is wrong. You wouldn't head it in trunk only because the backseat would muffle the noise, it would should be there. When you say your sub is a 2ohm, do you mean a dual voicecoil 2ohm, which is wired up to 4ohm? Edit: how did the shop set your gain for the amp, what equipment did they use? Did they happen to tell you the Max Clean Volume that your headunit can be turned up to before you start to distort the signal? Link to comment Share on other sites More sharing options...
8ten8 Posted August 18, 2017 Report Share Posted August 18, 2017 I believe you are correct in assuming the installers are full of bologna. Signal wires should be nowhere near the power and ground imo. Start with moving your rca's to the other side of the vehicle or thereabouts. RCA,s might be faulty also. Don't worry bout the size of the vehicle or under powering your sub... That's not droid your looking for Link to comment Share on other sites More sharing options...
Sion Nnjs Stephens Posted August 19, 2017 Author Report Share Posted August 19, 2017 On 8/17/2017 at 8:13 PM, 3vil said: Yeah, something is wrong. You wouldn't head it in trunk only because the backseat would muffle the noise, it would should be there. When you say your sub is a 2ohm, do you mean a dual voicecoil 2ohm, which is wired up to 4ohm? Edit: how did the shop set your gain for the amp, what equipment did they use? Did they happen to tell you the Max Clean Volume that your headunit can be turned up to before you start to distort the signal? Thats what I was thinking. Yes, its a dvc 2ohm thats wired to 4ohm. As far as the the amp goes, they set the gain at 12'oclock and the bass boost is 3/4 up. They did not tell me any info about how high it could be turned up, only that the issue was the size of the car. Thanks for your reply btw Kicker Comp Q 15 Kicker ZXS1500.1 Audiocontrol LC7i Link to comment Share on other sites More sharing options...
Sion Nnjs Stephens Posted August 19, 2017 Author Report Share Posted August 19, 2017 23 hours ago, 8ten8 said: I believe you are correct in assuming the installers are full of bologna. Signal wires should be nowhere near the power and ground imo. Start with moving your rca's to the other side of the vehicle or thereabouts. RCA,s might be faulty also. Don't worry bout the size of the vehicle or under powering your sub... That's not droid your looking for Thanks I will definitely try that, I'm actually going to go back to the installer again this weekend. Kicker Comp Q 15 Kicker ZXS1500.1 Audiocontrol LC7i Link to comment Share on other sites More sharing options...
Sion Nnjs Stephens Posted August 19, 2017 Author Report Share Posted August 19, 2017 What about the bass knob, is that normal or is there another underlying issue? Kicker Comp Q 15 Kicker ZXS1500.1 Audiocontrol LC7i Link to comment Share on other sites More sharing options...
Wishuponasub Posted August 19, 2017 Report Share Posted August 19, 2017 Your gain is most likely set to high. There are tools that can help you set your gains properly. DD1 is one of those tools. Also your bass boost should be at 0. You are sending A distorted signal to subs which is not good for them. Sitting around waiting to be installed: 4 FI X 10 270 CES alt D3400/73ah lithium AA 3800.1 (2) AA 75.4 Link to comment Share on other sites More sharing options...
YukonXL04 Posted August 19, 2017 Report Share Posted August 19, 2017 Did you buy this equipment from the shop? Wondering why they paired you up with a dual 2ohm sub on a mono amp only 2 ohm stable... 18 Sierra 6.2 Z71 : 3 F8L's, DD M2a @.67, 1.95@33 05 TL build log SOLD 04 YukonXL : jvc kw-v51bt , RE 6.5c, 4 jbl gt5 12s, Memphis pr1000.1 5.5 cu.ft. sealed Link to comment Share on other sites More sharing options...
Ahmed Johnson Posted August 19, 2017 Report Share Posted August 19, 2017 if you have a good pair of shielded RCA's you should be fine if the wires are ran together. There is another problem. I hate to say it but I think they gave you a bad sub. Check your ground. You could check to see if the signal wires is bad by getting a 3.5mm to RCA adapter and plug your phone or ipod straight to the amp. Link to comment Share on other sites More sharing options...
ShadeTreeMechanic Posted August 20, 2017 Report Share Posted August 20, 2017 I have seen a ground loop problem that caused a motor boat sound like what you are describing. That was 25 years ago and I'm trying to remember how we fixed it. lol 91 C350 Centurion conversion ( Four Door One Ton Bronco) 250A Alternator (Second Alternator Coming Soon) G65 AGM Up Front / Two G31 AGM in Back Pioneer 80PRS CT Sounds AT125.2 / CT Sounds 6.5 Strato Pro component Front Stage CT Sounds AT125.2 / Lanzar Pro 8" coax w/compression horn tweeter Rear Fill FSD 5000D 1/2 ohm (SoundQubed 7k Coming Soon) Two HDS315 Four Qubes Each 34hz (Two HDC3.118 and New Box Coming Soon) Link to comment Share on other sites More sharing options...
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