"Milky" (jordanmielke)
06/17/2015 at 11:33 • Filed to: Crossfire, Chrysler, Mercedes, Stereo
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"Milky" (jordanmielke)
06/17/2015 at 11:33 • Filed to: Crossfire, Chrysler, Mercedes, Stereo | 1
| 23 |
Stereo question and a photo dump for your time.
My stereo cuts out after about an hour of play, or if I hit a rather large bump. And by “cut out” I mean it only outputs bass. I’ve replaced the head unit, the amp and just for the hell of it all 5 fuses with stereo in the description. Thanks Mercedes. Any clue what else it could be?
Pretty images for clicking through.
And watchu know about rear visibility? Shout out to K-roll, bike is about to be working a lot better.
Mattbob
> Milky
06/17/2015 at 11:39 |
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Is there a separate amplifier? Also, by “only outputs bass” do you mean it only comes out of the subwoofer, or only bass comes out of all speakers?
RamblinRover Luxury-Yacht
> Milky
06/17/2015 at 11:44 |
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When you say “amp”, what all does that entail? Do you have one of those Bose systems with kind of a post-processing unit thingy? What it’s sounding like to me is some electric component like a FET getting warm and shifting out of contact, but I suppose it could be a connection in a gang plug somewhere...? I can’t think of anything not on a board that a bump would change the condition of. If you had the wires running straight from the head unit to the speakers as is normal, changing the head unit would in likelihood have cleared it up, but since it didn’t, that speaks to something, a thing managing speaker signals, being between the head and the speakers, and since a buddy’s W210 with Bose system had weird impedance values on the speakers for that, I have to assume the Bose system has a post-processing box.
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Milky
> Mattbob
06/17/2015 at 11:48 |
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Yes there is a separate amp, but I just replaced it and nothing changed. Might as well send it back now.
But I’m 95% sure only bass comes out of all the speakers, though tbh I haven’t checked specifically to see if its coming out of the door speakers too.
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Mattbob
> Milky
06/17/2015 at 11:53 |
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if it is just bass out of all the speakers, I would say it is from whatever handles equalizer duties for the car. Also check the speaker wires that they are not somehow making contact with the chassis and pulling the signal down when you hit a bump. Does the sound go in and out, or once it goes out does it stay out, and what resets it back to normal?
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Milky
> RamblinRover Luxury-Yacht
06/17/2015 at 11:55 |
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Honestly I’ve never done stereo stuff before so all of this is over my head. But for what its worth, its an Infinity system, here is the amp, and how its wired.
Which now after looking at it Im confused WTH is “body control module”, “data link connector” & “controller antilock brake”.
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Milky
> Mattbob
06/17/2015 at 11:58 |
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75% it goes out and stays out, but some other times another bump will bring it back …. so a wire hitting something does make sense.
Thats a lot of wires to check.
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RamblinRover Luxury-Yacht
> Milky
06/17/2015 at 12:09 |
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If I had to guess, the Body Control Module and ABS controller have the ability to switch off the amp for safety if you’ve been in an accident, so it doesn’t start a fire. Weirdly, I don’t know that the radio (outputting with only four wires) is outputting anything other than basic stereo, unless it’s outputting digitally. If it’s outputting digitally, you might have a bad connection that’s making it impossible for the amp to decode? That would be seriously weird. Regardless, something appears to be up with how the amp is handling things, because I see no indication that the head is doing anything other than outputting “left side, right side”.
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Milky
> RamblinRover Luxury-Yacht
06/17/2015 at 12:42 |
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Yea it is a weird system. There is no front to back fader in the car, since the “rear” speakers are only subs. But thanks, I’ll go search the forums for those 2 things and maybe look into some SLK stuff too, since those have been on the road longer.
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RamblinRover Luxury-Yacht
> Milky
06/17/2015 at 12:48 |
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If the rear speakers are only subs, I have *no idea* why they would have four wires. It makes no sense. I would expect that if they were a split-speaker with mini-tweeter or something like that.
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Mattbob
> Milky
06/17/2015 at 12:52 |
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do the different speakers have different connectors at all? I would try to disconnect the fronts or rears and see if it changes the behavior at all. If unplugging something makes the sound not go out on the remaining speakers, you might be able to narrow down where to look.
KusabiSensei - Captain of the Toronto Maple Leafs
> Milky
06/17/2015 at 13:02 |
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Not sure how things are set up (because Germans have done many strange things with car audio).
If you have separate speakers for bass and treble (separate tweeters), you will need to figure out if the crossover is mounted separately from the speakers, or if there is a crossover circuit in the radio itself. Also, if there is a loose connection on the tweeters, you could be hitting that with a bump.
If the schematic you have is for your car, what you likely have is a HPF on the tweeters and an LPF on the woofers for the doors. So the amplifier itself isn’t doing active crossover control.
The Chrysler Infinity systems tend to have less shenanigans in the amp than say the GM Bose systems (of which the Bose amp does the fade control with data bus input from the radio). The amp itself likely isn’t bad, but you either have a loose connection from the radio to the amp, or a loose connection from the amp to the HPF on the tweeter.
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KusabiSensei - Captain of the Toronto Maple Leafs
> RamblinRover Luxury-Yacht
06/17/2015 at 13:03 |
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I don’t think so. Normally the Chrysler Infinity systems use the ABS and BCM to trigger equalizer programs (specifically a separate equalizer program if a convertible top is not latched closed), and the speed signal for the speed sensitive volume, since those are controlled in the amplifier rather than the head unit.
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KusabiSensei - Captain of the Toronto Maple Leafs
> RamblinRover Luxury-Yacht
06/17/2015 at 13:04 |
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Dual voice coil speakers would be my best guess.
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Milky
> RamblinRover Luxury-Yacht
06/17/2015 at 13:05 |
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Every forum post about the stereo is 1 person saying what they did and 50 people being confused. Something about “pre outs” always get brought up. But as for the rear speakers, crutchfield says this “…. while the upgrade was an Infinity package that included two subs and an amp.”
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RamblinRover Luxury-Yacht
> KusabiSensei - Captain of the Toronto Maple Leafs
06/17/2015 at 13:06 |
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Possibably. It does seem like he’s entered the most dreaded zone of German electrical problems, though - the “odd digital problem caused by unknown and indirectly related analog failure” zone.
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KusabiSensei - Captain of the Toronto Maple Leafs
> Milky
06/17/2015 at 13:07 |
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You can have dual voice coil woofers with 4 posts per speaker (two per coil). This is likely what the rears are, if there is no high range mid-woofers or tweeters on the rears.
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KusabiSensei - Captain of the Toronto Maple Leafs
> RamblinRover Luxury-Yacht
06/17/2015 at 13:10 |
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My guess would be that the bridged inputs to the amp make sense since there is no fade control, and the amplifier would have to drive two voice coils per rear speaker.
The amp design is likely shared with other Chrysler products, so there is more likely to bee full range amplification with the high and low pass filters on the speakers themselves. Also, since the speakers are moving parts (and the only parts not indicated changed), it is possible that both mid-woofers and tweeters have failed at the same time. Given the age and origin of the car, that’s more likely that you would think (remember when the amplifier for the diversity antenna on my W210 failed?).
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Milky
> KusabiSensei - Captain of the Toronto Maple Leafs
06/17/2015 at 13:13 |
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For those us who don’t know, what does HPF and LPF mean? But yea its clearly not the amp or the head unit because I’ve replaced both.
So I should check the tweeters?
EDIT: yea that is the schematic for my car, Infinity system w/o nav.
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KusabiSensei - Captain of the Toronto Maple Leafs
> Milky
06/17/2015 at 13:19 |
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HPF = High Pass Filter. LPF = Low Pass Filter.
These are circuits that are inserted to filter out frequencies that a speaker is not able to reproduce. So for instance, you would have a High Pass Filter to block bass signals from reaching the tweeter (because the tweeter cannot reproduce those). Same thing with the woofers.
The speakers are the only things that you haven’t indicated that have been changed. Since both the amplifier and head unit in the dash have been swapped, and the behavior persists, I’m going to put money on bad connections in the wiring (either between the radio and the amp, or the amp and the speakers), or the speakers are bad.
Since it sort of works at times, I’m more of the mind that the connections may be loose in the harness. If you can, check the resistance that is present between the terminals at the amp and speakers, and between the terminals on the amp and the radio. You’ll need the ignition off and the amp and radio disconnected. The schematic at least includes the pin numbers.
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Milky
> Mattbob
06/17/2015 at 13:20 |
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Unfortunately no, its one big plug. Or two actually but you know what I meant.
That sounds like a solid idea though.
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Milky
> KusabiSensei - Captain of the Toronto Maple Leafs
06/17/2015 at 13:34 |
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Ahh I see, would it matter if was working or not before I check? I feel like not would make more sense.
Unfortunately Im going away through the weekend so it’ll have to wait until next week. But where I work has a shop and I know we have tools for that, so I’ll be able to do it.
66671 - 200 [METRIC] my dash
> Milky
06/17/2015 at 20:10 |
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I can’t help you with your problem but the dump was enjoyable, thank you.
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Milky
> 66671 - 200 [METRIC] my dash
06/17/2015 at 21:53 |
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Well thank you. And for a little self promotion, those images and many like them are on my tumblr.
http://mielkedesign.tumblr.com