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Discussion Starter · #1 ·
I want to put a 4 channel amp in with comps up in front. do I lose any major sq if i stick with the stock HU instead of switching for an aftermarket one? To me the appeal of the stock HU is the compatibility with all of the steering wheel controls and the looks of it fitting in with the rest of the dashboard.
 

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If you put in a sub, transformer style LOCs have a rolloff on bass response. The most expensive LOCs do this less.

Ironically, cheap resistive LOCs have almost no distortion at all, but they often have ground loop issues, so most LOCs use transformers to avoid that.

I have an internal LOC inside my sub amp, so I have no idea what technology it uses. It couldn't be a very expensive, since the sub amp cost less than some LOCs do by themselves, so I suspect that it is a resisitive loc or a very cheap transformer.

Perhaps there is a rolloff in the bass, but this could be compensated by the room gain of the car interior, so I still have good, solid low bass.

The main thing you lose with a LOC over head-unit replacement is the equalization and time alignment control you get with $300+ head units. I don't think there is much benefit with replacing the head unit unless you buy one that has these capabilities.
 

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Do you already have the amp? Because if not, you could just get an amp with speaker-level inputs, and not even need a LOC. That's what I decided, and it sounds just fine.
 

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Discussion Starter · #4 ·
I was shying away from the speaker level inputs simply because one of the workers at the local car audio place mentioned that they didn't sound very good. I understand that he isn't exactly an expert, but LOC's seem pretty common so i thought speaker level inputs must not be very good. So no problems with speaker level inputs?
 

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The speaker-level inputs on amps is kind of a crap shoot...some are designed well, others are not. I decided to go with a LOC for my Infinity BassLink, even though it has speaker-level inputs, ultimately because I prefer running RCAs over speaker wires and also in the event I upgrade my sub.

On the 3's factory headunit, I can tell you that the front speaker outputs are better to tap for an LOC than the rears...the amp in the headunit changes the EQ of the rear speakers based on volume to keep them from distorting, but leaves the fronts alone. My BassLink sounded like crap when I had my LOC tapped to the rear outs, then sounded much better when I moved it to the fronts.

Whether the overall sound quality of the factory HU is "good" is a hot topic here -- ultimately, only you can decide whether it's good enough for you. In my case, it was good enough considering the issues you brought up -- steering wheel controls and how it looks in the dash.
 

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^ that's interesting about tapping the rears. I have a LOC tapped from the rears for my sub amp, and a 4-channel using speaker-level inputs for all the door components, and don't have that problem... it all sounds great.
 

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[quote author=cali_axela link=topic=134397.msg2891329#msg2891329 date=1232995758]
^ that's interesting about tapping the rears. I have a LOC tapped from the rears for my sub amp, and a 4-channel using speaker-level inputs for all the door components, and don't have that problem... it all sounds great.
[/quote]

Did your car originally come with the Bose system? The only catch is that the Bose headunit actually outputs a perfectly flat, clean line-level signal (all of the amplification is done by the Bose amp under the seat). It's the non-Bose systems that mess with the EQ on the rear channels.
 

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Nope, I have the normal low-end stock headunit, no external amps or Bose anything.

EDIT: also installed a sub in my GF's new 09 iTouring without Bose last weekend. Her sub amp has speaker-level inputs (it's an Alpine MRP-500), tapped into the rear channels for that amp too just like with my own, and it also sounds great.
 

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I could barely even hear my Sub when I was using the Factory deck it was horrible. I had to pull it out and replace it with the 8Volt Head Unit I had in my garage.

There is no subsitute for good clean voltage.
 

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The OEM HU had absolutely nothing to do with "hearing" your sub. The gain was either set too low, or you had a bad/cheap LOC, or any number of things, but my sub hits just fine with the OEM head unit, using its internal LOC.

This is not to say that replacing the OEM head unit has some sonic advantages (as I mentioned earlier in this thread) but you can get very good bass performance with the OEM head unit and a sub.
 

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[quote author=cali_axela link=topic=134397.msg2891329#msg2891329 date=1232995758]
^ that's interesting about tapping the rears. I have a LOC tapped from the rears for my sub amp, and a 4-channel using speaker-level inputs for all the door components, and don't have that problem... it all sounds great.
[/quote]

thats funny too, i had my sub amp hooked up on front speakers and it was like i was not getting frequencies 30hz and below, changed it over to the rear and bam! all was good now the front is running my comp. amp
 

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^ yeah... i have a HPF on all my door speakers at around 50hz so I would not be noticing any loss of signal below 30hz to them... but the rear channels definitely send a good enough signal to my subs to sound consistent down to 20hz.

Not sure what your exact problem was with the stock HU CarAudiophile, but i've had great success using its outputs to power multiple amps without any issues. You sure the wiring was all good? Maybe the amp you chose just had really crappy speaker-level inputs, or your LOC (if using one) wasn't set up correctly.
 

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I would recommend getting a David Navone LOC. His are by far the best. I am getting 8v - 9v preouts to my RCA's and couldnt be happier with the sound.
 

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I'm Kindof a noob to audio ive got a quick question. If i were to buy one of the Subs that mounts in The jack compartment and buy a One of these speaker level amps is that all I need? along with the wiring of course. thanks guys
 

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yup! that's it.
 

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How hard would wiring it be on a scale of 1-10. Ive wired most of my stuff so i have some know how, but never sliced and diced before
 

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Ive been looking around but not been able to find much info on doing the wiring on a speaker level amp. Could anyone point me in the right direction I'd really like to try and do this myself and save some money ;P
 
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