WJBertrand

I'm planning to install the Shelby Kicker door speakers and door subs into my '13 Mustang GT Premium (standard Shaker system, not the Shaker Pro) this weekend. Regarding the subs, I've been reading on the forums that since you only use two of the four leads that are attached to the OEM subs, which evidently have two voice coils, that you loose some power there. The other two leads are left unused in the typical installation.

Has anyone tried connecting the two pairs in parallel, i.e. connect both (+) leads to one terminal and both (-) leads to the other on the Kicker subs? My thoughts are to capture all of the OEM amplifier output. I've no idea whether both leads carry the same signals or different signals. I can't think that it would cause a short circuit as long as you are sure which wire is which and don't connect negative to positive. Is it possible? Bad idea?

Thoughts?

jz78817

wow, that's silly. Not only do those woofers look like they have more moving mass (therefore lower sensitivity) than the factory ones, they expect you to give them only half of the power? What's the point of replacing them then? Kicker sells an 8" with dual 1 ohm coils which would make much more sense than these things (assuming they'll fit.)

No, you can't do that because the amplifier's output impedance is on the order of 0.01 ohms, so one channel with short out the other and one or both channels can be damaged. also it won't get you anything because the output signal and voltage is the same for both channels, and when you parallel voltage sources you get the same voltage.

WJBertrand

I'm not sure about the 1/2 power question. If the two coils in the factory sub are 2 ohms each and the Shelby Kickers are also 2 ohm (according to Shelby), then using only one set of leads makes sense to me. I just don't know how those separate leads are connected to the factory Shaker amp. I guess I could check continuity between the two (+) leads and if resistance is essentially zero could I assume they are already connected together somewhere up the harness. i.e. they are both originating from the same amp output? Similarly the (-) leads?

Thanks for the warning and the comment on parallel voltage, makes sense and I forgot my electronics 101 there for a moment. You should get more amps in parallel wiring though.

jz78817

oh, you have a 2013. crap, I was thinking of the 2010-2012 system. Your system has an 8 channel amplifier which powers all of the speakers. 4 of the channels are for the front 2-ways and rear speakers, and the remaining 4 go to the door subwoofers. Both woofers are 2 ohm dual voice coil, and each coil is driven by a separate channel from the amplifier. so there should be no continuity between any of those leads when the amp is off. I still don't see how the Kicker speaker makes sense; the amp can drive 2x40 watts to each subwoofer (80 watts total per subwoofer) only using one channel for the Kicker means you have 1x40= 40 watts total per subwoofer. It doesn't make any sense to me to just throw away half of your amplifier power.

only if you lower the load impedance.

WJBertrand

Hmmm, when I bought the speakers I didn't realize they were different having only a single coil vs. the dual coil OEMs. I'm looking to improve the clarity and sharpness/tightness of the bass, but not necessarily the power or volume. As it is, I can only turn the EQ on the bass up one or two ticks on the display before it gets boomy and just vibrates stuff in the car, not a good sound. Some tracks are worse than others in this respect.

Thanks for the information about the 4 channels used to drive the two speakers, didn't know that. I may just upgrade the door speakers and forgo upgrading the subs. Not much available out there that will fit though. I've dropped a note to Kicker to get their input too.

jz78817

that's because the bass control on that generation of radio is way too broad and boosts too much per step. changing the subwoofer speakers won't fix that. I have the bass up +1 on my 2012 Shaker 500 and I don't do more than that because it gets too muddy.

yeah, it's really tight in there. not so much the depth, but the diameter of the magnet causes problems. The factory 8" subwoofers get around that by using neodymium magnets; they're 10x stronger than the typical ferrite magnets so they only need to be 1/10th the size.

Chromeshadow

The Kicker 8" subs solve the space problem by sticking out about an inch more that the factory speakers. They supply a new speaker cover. I was able to modify the factory covers-I have the "premium" interior and I wanted everything to match. You will need an aftermarket amp to run them, you can find your own or get a complete system from Shelby.

Making a dual cone speaker is a work around. It allows Ford to claim a higher wattage than a single speaker cone. It's cheaper to design an amp like this as they can run it on 12V.
Most aftermarket amps have an internal DC to DC power supply that provides about 75V to the output stage. It's easier to get clear sound with a single coil that is 4 ohms or 8 ohms, but it costs more, it's larger and generates more heat.

jz78817

It isn't a "claim," it's actual power. the G445 subwoofer amp in my 2012 w/ Shaker 500 outputs an honest 8 volts RMS (which is all you can expect from a 12 volt BTL amp IC) into 1.2 ohms, which means it supplies a real 106 watts to each subwoofer. yes you lose a bit of efficiency due to higher current draw, but it's not worth discussing.

and don't confuse the issue. "Dual Cone" speakers are those full-range speakers which have the little "whizzer" cone attached to (or as part of) the dust cap. We're talking about dual-voice-coil subwoofers which are common in both OE and aftermarket.

Eh? "clear sound" has little to do with the nominal impedance. the voice coil inductance can have a notable effect on transient response, but L(e) is not constant across the operating range, and even if it's an issue there are ways to mitigate it such as a copper or aluminum shorting ring or cap. at any rate, L(e) mostly affects the top end response of the speaker but for subwoofers we don't use them up there anyway.

at any rate, when it comes to subwoofers, getting "clear sound" has far, far more to do with making sure they're crossed over properly and aligned in time with the mid/tweeter speakers. There's so much that can be done to tune an audio system properly, yet very little in the aftermarket allows you to do it.

Chromeshadow

We clearly disagree on this. Amps do not control the current, they control the voltage-which in turn controls the current. Using a higher voltage allows more steps to control the sound. Plus, all electrical components accuracy specs are for a certain voltage range. The closer they are to the min max value (o or 6V), the worse the specs are. The larger the voltage swing is, the easier it is to stay inside the best speced range.
In addition, the lower the Ohm rating on the speaker, the higher the current needs to be to get the same volume, which means more losses in the speaker wires and connections. If you have a 2 ohms speaker, and .2 ohms resistance in the speaker wires and connectors, you lose about 10% of the power. Using higher ohm rating speaker allows more power to the speaker.
Also-using dual voice coils means all of the components need to matched much closer that in a single voice coil. If the amp output components are +-10%, you have 4 errors to add or subtract and not just 2. (btw, errors can mean they are all added or all subtracted-they can average out or be cumulative) If one voice coil is driven harder than another, or slightly out of phase, it will sound muddy. A single voice coil has less of a probability to be mismatched.
I can tell you everyone who listens to my Sony driven Shaker 8" subs says there is no comparison the the standard 2012 shaker 500 system. We can argue all day about electrical theory, proof is in the puddin!

jz78817

ok then.

oh, BTW:

this is the same kind of mindset which convinces people they need to spend $1,000 on a 6 foot speaker cable.