need help with my amp and subs and stuff

[suprra_girl]

so i've got a vbd1400 head unit
manual > http://www.lanzar.com/manuals/VBD1400.pdf

a vibe 418 amplifier
manual > http://www.lanzar.com/manuals/Vibe218-228-238-248-258-268-418-428-438.pdf

on the head unit i only have one output rca for the subwoofer so i made a rca splitter for the amp
plugged it to ch 1 & 2 of the amp (the amp doesn't have L & R etc)
i have 2 12" subs but of course only one is powered up so i assume that because i only have one output from the head unit that i then use another set of rca's and go from the line out on ch 1 & 2 and plug into ch 3 & 4 line in?

hope that wasn't too confusing

reason i ask is that i suspect only one of the subs is going but i can't tell coz the subs shake the other subs when going lol

so have i got it wired properly?

here's a pic hopefully this helps lol

 

[NeoJester]

ok, first off what are the 2 subs you are using? and is rms/ohm rating for the amp and the subs? and do you just have a mono out on your head unit?

 

[suprra_girl]

12" lanzar subs, i think maybe 400w rms on each
amp is 2 x 200w rms bridged

and i dunno... there is just "one" rca for the subwoofer

thanks

 

[estrellainc]

i dont think anyone here knows that i am versed with music & engineering (4 of my works helped ziggy marley get a grammy in 98).
enough of the boring credentials, I am here to help ya make some sweet bass. :evil2:

i feel i should warn ya. Your setting yourself up for a nasty ground loop.
(it just sounds like normal hum).
The most severe cases of Ground Loop is INAUDIBLE.
The penalty for this is a burnt amp, or melted wires, blown speaker, or even a fire.

now-now, dont worry many people do it regularly,
ive used a similar setup temporarily myself with usable results. but theres a much simpler way to get past this. let me detail it.

1) an easy way to tell if the speakers are both workin is to reverse the polarity on one of the subs. wha??? just switch the + and - on one of the speakers, and only just one. if it right, it should cancel out a lot of the bass. if its not working, there will be no change in the volume of the bass.


2) as far as both woofers bein the same volume- no way; no mam!

theres a thing called resistance in the wires, (and anything else ya connect.) The "signal chain" pic ya posted tells me the signal has to go through the amps circuit board before going back to the input. this WILL reduce the sound level on that other channel because theres a longer path.

3) to help eliminate this nuisance, ya gotta "Y" the input wires BEFORE they get to the amp. (radioshack is the place to get an "RCA Y adapter")

the drawback is signal loss, but the levels will be the same. (pending wire choice of course)
always use equal lengths and lowest resistance always!
(this can apply to every part of the system. the speaker sizes too!)
You soundsystem will reward you with more dbs, better stereo, tighter bass!.
jus my 2 cents change from my (sicks) cents
G/L & ya go girl!

 

[suprra_girl]

cool thanks alot.. i'm gonna go try it now while the sun is out

 

[5uprahboy]

Can you please explain this ground loop you speak of? what causes it?

 

[estrellainc]

Can you please explain this ground loop you speak of? what causes it?

basically a ground loop is comprised of multiple connections of ground.

I.E.
More than one source for ground between two pieces of equipment.

this causes an imbalance of the input signal, an forces ground to seek the least resistive path to it. The results are unpredictable, and surely troublesome.

I did a google search on it. and found these resources
http://www.google.com/search?hl=en&q=ground+loop
(i edited this one for clarity)
DING DING- skools in session
Ground loop basics

What is ground loop?

A ground loop occurs when there is more than one ground connection path between two pieces of equipment. The duplicate ground paths form the equivalent of a loop antenna which very efficiently picks up interference currents. Lead resistance transforms these currents into voltage fluctuations. As a consequence of ground-loop induced voltages, the ground reference in the system is no longer a stable potential, so signals ride on the noise. The noise becomes part of the program signal.
Ground loop is a common wiring condition where a ground current may take more than one path to return to the grounding electrode at the SERVICE PANEL. AC powered computers all connected to each other through the ground wire in common building wiring. Computers may also be connected by data communications cables. Computers are therefore frequently connected to each other through more than one path. When a multi-path connection between computer circuits exists, the resulting arrangement is known as a "ground loop". Whenever a ground loop exists, there is a potential for damage from INTER SYSTEM GROUND NOISE.
A ground loop in the power or video signal occurs when some components in the same system are receiving its power from a different ground than other components, or the ground potential between two pieces of equipment is not identical.
Usually a potential difference in the grounds causes a current to flow in the interconnects. This in turn modulates the input of the circuitry and is treated like any other signal fed through the normal inputs. Here is an example situation where two separately grounded equipments are interconnected though signal wire ground and the mains grounding wire. In this situation there is 1A current flowing in the wire which causes 0.1V voltage difference between those two equipment grounding points.

Because there is voltage difference between the equipments, the signal in the interconnection wire sees that difference added to signal. This can be heard as humming noise on the wire because the AC current cause the voltage difference of those ground potentials to be also AC voltage. This is one reason for this 50 Hz or 60 Hz noise you hear in the audio signal (or see in video signal as annoying horizontal bars).
Another problem is the current flowing in the signal cable grounding wire. This current passes though the cable and through the equipment. Because of the way the current passes is not well designed this can cause lots noise to the equipment or other kind of problems (like computer lockups). Lots of designers count on ground being ground and do not optimize their design to eliminate their sensitivity to ground noise. If you are a product designer remember to take care that ground loop current does not cause problems in your equipment by designing proper grounding scheme inside the equipment.
Why ground loop is a problem?

Ground loop is a common problem when connecting multiple audio-visual system components together; there is a good change of making nasty ground loops. Ground loop problems are one of the most common noise problems in audio systems. Typical indication of the ground loop problem is audible 50 Hz or 60 Hz (depends on mains voltage frequency used in your country) noise in sound. Most common situation where you meet ground loop problems are when your system includes equipment connected to earthed electric outlet and antenna network or equipments connected to different grounded outlets around the room.
Everything connected to a single mains earth, which is usually connected to all the earth pins in all the power sockets in one room. Then antenna network is also grounded to same grounding point. This would normally be okay, as the grounding is only connected to each other in a star-like fashion from a central earth wire (leading to the real Earth via a grounding cable or metal pipe) earth cables run through your power cables into the equipment.
Once you take into account that some of your equipment is linked with shielded cable you are quite likely to face some problems. Currents could quite possibly run from one piece of equipment, into the earth cable, into another piece of equipment, then back to the first piece via a shielded audio cable. That wire loop can also pick up interference from nearby magnetic fields and radio transmitters.
The result is that the unwanted signal will be amplified until it is audible and clearly undesirable. Even voltage differences lower than 1 mV can cause annoying humming sound on your audio system.
A problem with audible noise coming from your audio system when other electronic components (fridge, water cooler, ect.) could be the result of a contaminated ground/neutral conductor in your A/C wiring and a ground loop in your audio system. This can happen when certain type of devices come on. Typically their power supplies are non-linear and throw garbage back onto the neutral and/or ground conductors. Usually line conditioners or UPS devices will not do anything to help solve this problem.
Common Causes for Computer System Problems

Many times when a user thinks that his system is 'bad' or has 'gone bad' the fault is electrical or magnetic in nature. Monitor problems are very often caused by nearby magnetic fields, neutral wire harmonics, or conducted/transmitted electrical noise. Intermittent lockups of computers are very often the caused by a Ground Loop, an electrical phenomena that sometimes manifests itself when a system and it's peripherals are improperly plugged into different electrical circuits. Many don't even know if their wall outlet is properly wired and grounded, an absolute necessity for a computer and peripheral to operate reliably and safely.
Have you ruled out Ground Loops in your computer system? Ground loops can cause problems to LAN connections if not properly wired. A ground loop caused by RS-232 connection to other computer can cause computer lockups.
When ground loop is not a problem

Ground loop does not cause problems when all of the following things are true:

• None of the wires in the loop carry any current
• The loop is not exposed to external changing magnetic fields
• There is no radio frequency interference nearby

If there is any current following in any wires, there is then some potential difference which causes current to flow in other wires also which causes problems. The loop will also act as coil and pick current from the changing magnetic fields around it. Wire loop acts also like an antenna picking up radio signals.
What size of ground potential difference problems we are talking about?

Literature is speaking about Common Mode Noise of 1 to 2 Volt in "well grounded" plants and over 20 Volts in "poorly grounded" plants. Literature is also speaking of the current measured on a main service grounding (in a large building) in terms of Amps.
Where does this current and voltage difference come from ?

Current leakage of condensers between hot and ground and between neutral and ground, in for instance main filters, cause current in ground wires (and ground loops). The leakage current is typically measures in milli-amperes (typically less than 1 mA in computer equipments) per equipment. When you sum up maybe hundreds of such equipments you can easily get amperes.
The capacitance between line and ground of large heaters and motors, for example, can be much larger than the capacitance in filter capacitors. Currents from this source are usually of the order of 1 amp (rather than 0.1 A or 10 A)
Even a very small induced voltage can cause a very large current in a ground conductor loop, because the resistance (and inductance) is very low. These currents can indeed be tens of amps. Current induction can be caused for example by cables carrying high currents and from transformers.
What those grounding currents and voltage differences can do?

Small voltage differences just cause noise to be added to the signals. This can cause humming noise to audio, interference bars to video signals and transmission errors to computer networks.
Higher currents can cause more serious problems like sparking in connections, damages to equipment and burned wiring. My own experience on the field is limited to sparking connectors, heating cables and damaged computer serial port cards. I have read about burned signal cables and smoking computers because of the ground differentials and large currents caused by them. So be warned about this potential problem and do not do any stupid installations.


personally, ive shocked myself enough to wonder when it all gonna come back out. (i'll prolly zap my wife first! lol!)
hope the jibberish helps!

 

[5uprahboy]

WOW thanks for that - rather informative

 

[estrellainc]

ya shoulda seen the faces on a client i had once- the CB radio played right through my system! breaker- breaker 1-2 ! puzzzzzzap!

 

[suprra_girl]

lol

well i got my subs cranking today, appears they only like to play when all exits are closed hehe

Thanks heaps for the help

 

[Fuzz420]

3) to help eliminate this nuisance, ya gotta "Y" the input wires BEFORE they get to the amp. (radioshack is the place to get an "RCA Y adapter")

I bought my y-splitters from there they were fair priced, but the quality sucked, my wired started shorting out after a few months of use.I bought 4 sets and only two lasted the year my system was in,i would definetly search for a slightly higher quality component here, but if you gotta have it now, go to radio shack.

 

[5uprahboy]

lol

well i got my subs cranking today, appears they only like to play when all exits are closed hehe

Thanks heaps for the help

Mine are the same. As soon as you open the doors or the boot the sound changes and it's no where near as loud inside the car. Having the windows open is ok tho.

 

[aznwaterboy]

i got a question, i'm trying to put an amp and a sub into my car right now but i can't seem to find a place to put the wire from the battery to my amp. i can't seem to find a hole in the firewall to feed the wire through, can someone help me and also pics would be nice too, its a 90 7mge supra so i think that should help a little bit.