Mach stereo with aftermarket head unit, no bass...

Discussion in 'SVT Tech Forum' started by millhouse, Jun 9, 2010.


  1. millhouse

    millhouse Founding Member

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    I just picked up a 97 cobra convertible (actually traded my TT 5.0 fox for it) and noticed the surprisingly lack of bass from the system. Now, while I'm not intimately familiar with the mach setups…I was expecting more from the bass department. The previous owner recently installed a newer sony x-plod head unit. All speakers seem to be working and hooked up to the proper channel, as the f/r fade and l/r balance seems to adjust properly. Is this just normal for the verts, as they don't have any speakers in the decks (as they don't actually have a rear deck)?
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  2. Steve491

    Steve491 Member

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    Assuming this website is correct you should have subwoofers in the trunk. If they were removed then you won't have much bass, especially in a convertible.
    Mach 460 Information
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  3. millhouse

    millhouse Founding Member

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    It looks like the sub's are only found in the mach 1000 systems. Mine has no subs in the trunk.
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  4. Steve491

    Steve491 Member

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    I didn't notice that in the picture. My 97 had the head unit ripped out and a woofer box in the trunk when I bought it so I don't know what the original configuration was.
    It sure seems like they would have put some sort of subwoofer in the trunk from the factory because the rear speakers were in the quarters.
    In the olden days a couple of decent speakers in the rear deck would do pretty good with the trunk as an enclosure. :)
    Get a small bass box with an amp and put it in the trunk, kinda like the old bazooka tubes, unless you want ground pounding bass. Personally I prefer exhaust over bass.
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  5. millhouse

    millhouse Founding Member

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    Back in the day, a pair of 6x9's in the rear deck was plenty bass for me! With the loudness now turned on...it is plenty bass for what I need it for. When I crank it up too much it distorts ever so slightly...but without the loudness turned ON, there is literally NO bass...it's all mid's and highs!
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  6. lang williams

    lang williams New Member

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    My car came with boss unit with the pop out dvd screen. It sounded great to me, good bass but the memory was lost every time you turned the car off. I got tired of it an bought a cheap sony explode an now no bass. I prob have a bad connection in the adapter harness I had to make.
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  7. millhouse

    millhouse Founding Member

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    I don't know man, did you turn the loudness on?
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  8. lang williams

    lang williams New Member

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    I've tried all the settings. I'm thinking maybe the 12 v to the amp is a bad connection an not turning all the amps on.
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  9. Charged01cobra

    Charged01cobra New Member

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    i have this same problem, just bought a brand new pioneer head unit and wire adapters so i dont have to cut the factory harness..... sounds like absolute dog crap to me all the speakers are working its just distorted and muffled i personally think that you cant beat the sound of the stock sterio but they all seem to have problems with the 6 disc changer part so its prety much a lose lose situation.
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  10. millhouse

    millhouse Founding Member

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    Yeah, well...I spoke too soon. While it sounds ok with the car off, the exhaust immediately cancels out any bass. In other words, while driving down the road I can't even hear the bass line in Brass Monkey...WTF!
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  11. Charged01cobra

    Charged01cobra New Member

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    when you wired in your radio did you hook up both of the amp positive wires to your power antena/amp wire or just one? because you need to hook up both of the blue/ white stripe wires for both the amps to kick on. Also, your radio might have a sub woofer adjustment just like regular bass/treeble and it might be on 0..... mine has no adjustment i just found out and i am getting full range out of my larger speakers where before they where only supposed to get just bass so i have no idea how to fix my problem.
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  12. millhouse

    millhouse Founding Member

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    I didn't hook up the stereo, it was already done when I picked it up. All speakers are actually working…it's just that the bass isn't very loud or distinct. When I do crank up the volume, instead of the bass having a small amount of thump it just distorts. Hell, even my 2004 F150 has MUCH better bass then this cobra.

    I have already adjusted the bass all the way up and ensured the low and high pass was turned off in the head unit. I was hoping I wasn't going to have to dig in to the damn wiring on this ****!
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  13. millhouse

    millhouse Founding Member

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    Ok, after doing some research I think I may have found some things out. While I don't know for sure (yet) how he has it wired up…I'm assuming it's wrong. The head unit I have is a low-buck newer Sony Xplod unit which does not have 4 RCA line-out's. Because of this, a simple harness adapter such as the Metra 70-5510 will not work, as it needs to be hooked up to all 4 to function properly. The reason for this is because you need a low level line out for all four channels to properly drive the amps. The stock headunits output basically needs to be dropped down in intensity. With that said, what I would then need would be something that converts the signals from the Sony head unit's speaker wires to a lower level line out. Something along the line of the Scoche SLC4 or this… Factory System Integration Adapter 1988-up Ford/Lincoln/Mercury/Mazda/Nissan at Crutchfield.com . Considering he has the thing hooked up and working, I'm thinking I won't need the later…as I likely have all of the connectors already in there and the SLC4 should then do just fine. If by chance I already have something of the sort in there…I either need to lower the gain or I'm SOL and the MACH 460's just sound like ass (no bass, distorts with the volume turned up high).
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  14. millhouse

    millhouse Founding Member

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  15. millhouse

    millhouse Founding Member

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    Ok, he clipped the friggen wires in the doors/panels and bridged both woofers and tweeters together. No wonder it sounded like ass.

    Anyways, with everything hooked up it seems the right rear amp is producing a buzz and not putting out anything to the rear woofers. I could wiggle the rear plug and get the buzz to go away, but it doesn't make the woofers work. I simply disconnected the plug going to the amp and the buzz went away (but again, no rear woofers). These should have 3 wires for the rear amp plugs, correct?

    More good news, the left rear tweeter is blown completely while the right rear tweet is working as are the front woofs and tweets. Even with all of this chaos going on, this setup sounds WORLDS better than having 4 channels from the head unit feeding all 8 speakers! Seriously, everything is more crisp and I have a ton more base (without the rear woofers even working!)!

    On a side note, while pulling apart the Shi#$% wires (which were simply twisted and taped)and solder/shrink-wrapping, I noticed there were some wires from the factory harness not being used. The first being a Black wire (connected to orange/black stereo wire which was clipped), the second being a Blue/Red wire (connected to orange/white stereo wire which was clipped) and a black wire which is taped to another wire with some sort of single clip on it. Does this sound right?
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  16. stanggirl14

    stanggirl14 New Member

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    In case you haven't seen the other posts here's the wiring diagrams for the Mach 460 and mach 1000. Mach 460 Information

    You have 3 amps, the one in the front runs all 4 tweeters, the two in the rear run the two front woofers and two rear woofers, so one amp for front, one for the rear.

    My experience with wiring up an aftermarket head unit is you need the adapter you posted from crutchfield to make everything work. Sounds like he screwed up your system, good luck!:D
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  17. millhouse

    millhouse Founding Member

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    Ok, another small update.

    While the sounds was MUCH better with the amp driving the rear woofers, the lack of sound in the front's due to the broken amps was really bugging me.

    If you recall before, they had the front speakers hooked up in series. This meant that the two 6 ohm speakers that were connected together (woofer and tweeter per side) were pulled down to 3 ohms, which I'm assuming is why it sounded like poo. Seeing as the tweets were now working great hooked up to the factory amp and running through the RCA's from the head-unit as are the rear woofers, I decided to go ahead and hook up the front lower door speakers to the head unit's speaker outputs. Because the head unit can comfortable handle between 4 and 8 ohms, the results were awesome. With all 4 woof's firing the sound is much more full. The only issue I can see is how to limit some of the high's from the woof's as you really can't control the cross-over separately.
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