[mathematics]

I don't know if you guys remember from a few months back my post about doing 8" mids in fiberglass kicks, but they are finally being done. Stay tuned for pics!!

[TMR]

sounds AWESOME!. Tru amps are no joke.

[mathematics]

2 custom modded Billet 4100's, Zapco DSP6, Dynaudio Esotar 1200 sub infinite baffle setup where the factory storage pocket is behind rear armrest, Dynaudio Esotec MW 172 in the kicks, and Dynaudio Esotec System 222 in stock location for midranges and tweeters.

[mathematics]

here we go

[VP Electricity]

Pretty gear.

[mathematics]

thank you. still doing a lot of work: adding another Tru Billet 4100 and Zapco DSP6 in the trunk before it gets all cleaned up. Also waiting on the fiberglass kicks for the 8" midbass' to be completed sometime in the next 2 weeks hopefully.

[VP Electricity]

The way your baffle is set up, doesn't the sub hit the back of the insert when it's in place?

Are one set of those RCAs coming from a ground-loop-isolator?

Does your car have Logic 7? Where are you getting your signal for the amps?

[mathematics]

The sub doesn't hit anything. The rear trim panel is cut out and covered in grill cloth.

Signal path: No logic 7. Front two channels are tapped after the factory amp then sent to an LOC. The LOC then feeds a TruTechnology Line Driver (Stereo in-6 channels out).

Note: those cheesy looking RCA's you see are coming from an AudioControl Epicenter that i was playing around with.

[VP Electricity]

Originally Posted by mathematics

Note: those cheesy looking RCA's you see are coming from an AudioControl Epicenter that i was playing around with.

Ah : )

Originally Posted by mathematics

The sub doesn't hit anything. The rear trim panel is cut out and covered in grill cloth.

Cool.

Originally Posted by mathematics

Signal path: No logic 7. Front two channels are tapped after the factory amp then sent to an LOC. The LOC then feeds a TruTechnology Line Driver (Stereo in-6 channels out).

Since the Tru line driver has balanced inputs and the HU outputs are also balanced, you can run the signal directly into the Tru line driver (or into the Tru amps directly, for that matter).

You are losing lots of voltage in the LOC that you don't need to lose (it's not speaker level, so attenuation is pointless), and then boosting it in the line driver. Cleaner signal and less noise if you eliminate the LOC.

[mathematics]

probably will lose the LOC, but currently I have 0 noise

[VP Electricity]

Everyone has a noise floor. Glad you're not hearing yours.

If you ditch the LOC, you will gain 3dB of signal out of the HU. Currently (unless you are using an active LOC which really isn't an LOC at all) you are tossing the (-) half of the signal. You can get a cleaner signal and a higher-voltage signal by using both sides, the way a real balanced input allows.

And I would be way interested to start your car, turn on your high beams, R defroster, blower motor, and any seat heaters, and listen for noise.

[mathematics]

the head unit's output is not balanced. balanced outputs have 3 leads (positive, negative and ground) since the circuit in use is a differential circuit. you can't "toss" half of a signal. that would be like running your signal through a diode and rectifying it. you cannot have balanced signals with RCA-type interconnects. two pins of a balanced line have he same signal, just 180 degrees out of phase, along with the ground. this is for internal circuitry to detect noise. technically speaking, a system isnt balanced unless the internal circuitry is designed as balanced. in other words, balanced transmission is pretty much useless without the circuitry to detect/correct noise in the balanced system.

[VP Electricity]

Originally Posted by mathematics

the head unit's output is not balanced. balanced outputs have 3 leads (positive, negative and ground) since the circuit in use is a differential circuit.

I used to make some of this this argument, and I was wrong when I made it, too. I had some pro audio guys who are active on DIYMA - especially Chad - set me straight.

First off, the HU output IS balanced, buddy. Gotta disagree with you on this one. Bet you $20 PayPal : )

Balanced signals only require a reference ground, not "three wires". Pro-style XLR cables do carry a reference ground per channel, but you only need one reference ground for a multi-channel system. It can be your electrical ground if you like.

As you probably know, balanced differential signals are not AC signals - they are "clamped DC" signals, one always positive, one always negative ("clamped DC" is the technical term for a signal which varies in voltage, but which does not cross the 0V line, from + to - and back again).

What most LOCs do is "shift" the clamped DC of one signal leg back to AC by using a shunt capacitor and/or a transformer (also dropping voltage on the way thru), and then run the other leg of the signal through a resistor network so that if the outer shield of the RCA connector is common-grounded, there isn't a "hard short".

That is what I mean by "tossing" half the signal - what I should have said, perhaps, is losing one leg of the signal and the corresponding amplitude, because only amplitude is lost, not frequency (excluding insertion losses of the LOC itself).

From what I've learned after having this discussion with pro audio guys, RCA-input-CONNECTOR, but balanced-differential-input-STAGE amplifiers like the Tru, JL, Arc, Audio Control, etc., do not take the (-) signal on the RCA shield to ground. They invert it and take it to a differential amp (the (+) is going to another differential amp without inversion). If the (-) is grounded, no harm is done to the signal. If the (-) is balanced mirror-image, then you get the amplitude back.

I seriously suggest you do a bit more research on this car and on the topic, because you have some nice gear there, in a nice car.

Check OEinterface.com, too.

[mathematics]

only one way to find out...oscilloscope and sin wave

[VP Electricity]

Jeez...I need to video EVERYTHING!

I have done such a test in several vehicles using a Fluke Scopemeter, a 0dB sine wave, and an RTA. Would you like me to YouTube it? I need to make some videos anyway ...

[mathematics]

hell yea, youtube that shit lol. that Fluke is nice

[mathematics]

finally some progress. sorry for the shitty pics. i had to take them with my cell.

[VP Electricity]

Are the pods sealed or open back?

[mathematics]

sealed with polyfill added

[VP Electricity]

Sealed that small, you will probably have a upper midbass peak you will need to EQ out, and the lower midbass will rolloff fast. If you have enough power the DSP6 will let you correct... but remember, +3dB=2X the wattage

[amlebede]

How is that speaker on the floor in front of the pedal not annoying?

[mathematics]

Originally Posted by VP Electricity

Sealed that small, you will probably have a upper midbass peak you will need to EQ out, and the lower midbass will rolloff fast. If you have enough power the DSP6 will let you correct... but remember, +3dB=2X the wattage

oh, i have plenty of power...as you can see lol.

also, the black carpeting is temporary.