Car Audio Questions

[Exit]

My 09 Corolla has a passable factory sound system, but I am looking at adding a subwoofer and amp with the least amount of disassembly and cost. I already have a leftover JL Audio 12" sub and enclosure, so I only need to select the amp and wires and possibly and EQ or processor.

I want to just tap off of the rear deck speakers and feed the signals to the speaker level inputs of the amp. Will this work or will it lower the impedance of the speaker load and screw up the factory head unit? Do I need to disconnect the rear deck speakers to make this work? One source I read recommended taking out the rear deck speakers anyway to allow the subwoofer sound to more efficiently enter the passenger compartment from the trunk.

The front car speakers have a bass cutoff at 45 Hz. I was thinking I could put capacitors on the front channels and raise the cutoff point above 79 Hz to get rid of some of the 79 Hz spike. Then I could control the subwoofer bass at 79 Hz with an EQ.

The car has a 15dB spike at 79 Hz measured using sine waves and an RS meter. I have only measured from 158 Hz down so I still have to measure the full 20Hz to 20KHz to see what is going on with the rest of the frequency range. In any event I would like to find something like a BFD DSP1124P parametric equalizer where you can set all the filters parameters versus fixed frequency type, only for a car, and less than $200, to get rid of the 79 Hz spike and any other anomalies. I prefer a manually setup EQ versus automated.

All suggestions welcome.

 

[Sounds Good]

i dont have any experience with it, but ive only heard good things about the Infinity Basslink..

 

[GlocksRock]

The easiest thing to do is just add an amp with high level inputs, or get a line output converter, so you can use the rca inputs on the amp. Depending on your amp, not sure what sub you have, but as long as you aren't running a powerful amp, you will be good with an 8 gauge amp kit. Another option is to replace the front speakers with some nice coaxials, and get a 4 channel amp, that way you can run channels 1 & 2 for the front speakers, and cross them over wherever you want, and bridge the other 2 channels for your sub.

 

[speakerman39]

The easiest thing to do is just add an amp with high level inputs, or get a line output converter, so you can use the rca inputs on the amp. Depending on your amp, not sure what sub you have, but as long as you aren't running a powerful amp, you will be good with an 8 gauge amp kit. Another option is to replace the front speakers with some nice coaxials, and get a 4 channel amp, that way you can run channels 1 & 2 for the front speakers, and cross them over wherever you want, and bridge the other 2 channels for your sub.

Great advice here Glock! We use line-level converters all the time. When we do, we use T-taps to get a signal which does NOT cause any problems with impedance. It works great most of the time whereas at others added noise becomes a problem. It is surely worth a try.



Cheers,

Phil

 

[annunaki]

Depending upon the factory audio system, line level converters are not always an option. Many of the factory systems' amplification have pre-corrected response to compensate for shoddy speakers. In other words the output sent to the speakers is eq'ed & crossed over limiting bass response to speakers.

Unless there is a factory sub woofer to get a line level signal, your best bet will be to use a JL Audio Cleansweep, or MTX Re-Eq, or Alpine's option (don't know model or name). This corrects the factory response deviations and outputs a flat 20hz-20hz signal.

 

[GlocksRock]

Depending upon the factory audio system, line level converters are not always an option. Many of the factory systems' amplification have pre-corrected response to compensate for shoddy speakers. In other words the output sent to the speakers is eq'ed & crossed over limiting bass response to speakers.

Unless there is a factory sub woofer to get a line level signal, your best bet will be to use a JL Audio Cleansweep, or MTX Re-Eq, or Alpine's option (don't know model or name). This corrects the factory response deviations and outputs a flat 20hz-20hz signal.

Don't forget about the Rockfor Fosgate three sixty.

 

[Exit]

I have been looking at mono amps with line level inputs. I have also been looking at amps that have differential balanced inputs as I have read that these are a lot easier to install yourself without noise problems. The subwoofer is rated 150 W rms normal and a maz of 300 W rms.

I am looking closely at JL Audio 500/1v2, Kicker ZX750.1 and ZX500.1 and Hiphonics TXi1008D. right now.

If differential balanced inputs are no big deal, then I have identified another 17 amps that may suit my purposes. I want to try to just add the amp/sub and only a processor later if need be. Most processors require amps for the speakers which I don’t want to do right now. I also don’t want to get into the dashboard or doors and replace speakers at this time. So I want to start off simple and relatively low cost, and have the amp good for the future (RCA low level inputs too)..

The JL Audio unit is probably more power than I need (or is there no such thing), but it is rated very conservatively with good specifications and features so I am leaning that way unless I can find a lower cost unit with about the same specifications for S/N, THD etc.

So what do you think about differential balanced inputs or anything else I should know.

 

[GlocksRock]

The JL amps are very nice, and can also be set to turn on via input signal instead of using a remote wire, and I would choose either the JL or Kicker amps over the HiFonics, not that HiFonics is all that bad, but the others are much nicer amps. You don't need balanced inputs either, just rca inputs will be fine. But if your sub is only rated at 150 watts, and you don't plan on upgrading to anything much more in the future, you may be better off with the JL 250/1.

 

[agarwalro]

Found this on Crutchfield, http://www.crutchfield.com/p_543ADP12/Russound-ADP-1-2-Speaker-level-to-Line-level-Adapter.html?tp=9070&tab=detailed_info

I don't know if any speaker to line level converters that can work as a splice, that is, also let you send signal to speakers. Adding the splice will impact the impedance your head unit sees and therefore might not work out for the deck lid speakers.

Unless you are comfortable taking off pannels, identifying and splicing into existing wiring, running new wires and reattaching everything, pay to have it done. You will get warranty on the work and the last thing you want is electrical issues in the car's harness that causes a major problem somewhere else.