Kaleb Posted May 5, 2017 Report Share Posted May 5, 2017 I have a bmw with the base stereo. Ive added a lc7 along with a 5 channel alpine amplifier. I have a lot of static with my volume down and my engine off, I've even tried upgrading to a DSP and if anything it makes my static or humming worse. After doing some testing i have found a problem. While playing a test tone i checked my signal voltage for all the wires on the lc7 coming from the head unit. As i understand signal voltage should be in the 5v-10v range. 3 of my signal wires read 6-7 volts and one signal wires reads 40+ volts. I know how to check signal voltage all i do is put multimeter in DC and test positive and negative speaker wires coming from head unit. Any idea why one signal wire would have so much coming through it? Quote Link to comment Share on other sites More sharing options...
reedal Posted May 5, 2017 Report Share Posted May 5, 2017 Signal voltage is AC, not DC...... Quote SMD Tool Map https://www.stevemeadedesigns.com/board/topic/193176-smd-tool-map-new-november-2014/ Build log https://www.stevemeadedesigns.com/board/topic/197217-reeds-03-tahoe-hat-sqaq-singer-xs-shca-cockbox-80prs/?page=32 Link to comment Share on other sites More sharing options...
Kaleb Posted May 6, 2017 Author Report Share Posted May 6, 2017 21 hours ago, reedal said: Signal voltage is AC, not DC...... Thank you I've realized this and I got confused by the Millie volts reading thinking it was volts . I've been trying everything to diagnose my main problem and I thought I had a lead. My main issue is when I disconnect all my rcas going from lc7 to amp, I can play music and still faintly hear it coming through my speakers, I'm pretty good but I'm no profession and I've never seen this before I have no idea what could cause it. Has annoying else ever experienced this ? It just seems impossible for the sgnal to travel with the rcas disconnected. It's like the signal is traveling through air just enough so when you put your ear to the speaker you can hear it as long as the volume is up all the way Quote Link to comment Share on other sites More sharing options...
ShadeTreeMechanic Posted May 6, 2017 Report Share Posted May 6, 2017 Try unplugging the rcas from the amp and see if it still does it. With the gain set high on the amp, it might be possible for the rcas to pick up an induced voltage from wires running next to it like the factory wiring or something. When you say static noise is it like an air sound mostly from the tweeters? This is caused by the gain being set too high. Is there anyone in your area with a DD-1? it might be worth buying one. The eq that I run has a pre amp in it so I can turn my gains way down low to get rid of this noise. Maybe the LC7 has an adjustable output, I don't know. Quote 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...
deathcards Posted May 6, 2017 Report Share Posted May 6, 2017 static also has a possibility of coming from a poor factory ground diagnosing is fun....not Quote skar sk2500.1 0 gauge power and ground kunukonceptz alpine HUvxi65 components on BA gt-275new build log -> http://www.stevemeadedesigns.com/board/topic/150642-project-d-kon-deathcards-build-log/#entry2148821 2 x-15 sundowns singer alt, odyssey bat, and maxwell ultra caps Link to comment Share on other sites More sharing options...
bmwking Posted May 6, 2017 Report Share Posted May 6, 2017 i, too, have a bmw and had audio issues. what year is your car? also, where did you tap in your lc7? I was running into turn on pop, engine noise, and static hiss with my 4 channel until i finally had the epiphany to look and see that even tho i had the base stereo, it's still amplified. i bypassed the factory amp, and *poof* all my issues disappeared. wish i had thought of that before i threw money at it, but whatever. so yeah, check where you tapped in for your signal wire to the loc, make sure it's before the amplifier, not at the speaker. best idea would be directly out of the head unit. Quote Link to comment Share on other sites More sharing options...
reedal Posted May 6, 2017 Report Share Posted May 6, 2017 44 minutes ago, Kaleb said: Thank you I've realized this and I got confused by the Millie volts reading thinking it was volts . I've been trying everything to diagnose my main problem and I thought I had a lead. My main issue is when I disconnect all my rcas going from lc7 to amp, I can play music and still faintly hear it coming through my speakers, I'm pretty good but I'm no profession and I've never seen this before I have no idea what could cause it. Has annoying else ever experienced this ? It just seems impossible for the sgnal to travel with the rcas disconnected. It's like the signal is traveling through air just enough so when you put your ear to the speaker you can hear it as long as the volume is up all the way The RCAs you have are likely of poor quality and the signal is escaping the shielding and entering the speaker wiring. Can we get a better rundown of ALL of the equipment you're using? How did you tune the LC7 and amplifier? How did you determine where to set your gains? Where are all of your ground wires grounded at? What RCAs are you using? Quote SMD Tool Map https://www.stevemeadedesigns.com/board/topic/193176-smd-tool-map-new-november-2014/ Build log https://www.stevemeadedesigns.com/board/topic/197217-reeds-03-tahoe-hat-sqaq-singer-xs-shca-cockbox-80prs/?page=32 Link to comment Share on other sites More sharing options...
Kyblack76 Posted May 6, 2017 Report Share Posted May 6, 2017 I was gonna suggest tapping in BEFORE the oem amp. Quote SMD SUPER SELLER The Burban Build Blazer Build sold Acura trunk build sold Link to comment Share on other sites More sharing options...
bmwking Posted May 6, 2017 Report Share Posted May 6, 2017 also, wrong sub forum lol but whatevs Quote Link to comment Share on other sites More sharing options...
bmwking Posted May 6, 2017 Report Share Posted May 6, 2017 Just now, Kyblack76 said: I was gonna suggest tapping in BEFORE the oem amp. that's because you're smart Kyle Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.