Powered sub's

[RamAirZ]

I wasn't even thinking about the different signals per side. I'm just used to running on RCA's. As for output being cut, why would that be? and why would the front speakers suffer, because of the "power" getting fed in multiple directions.

[Grif]

I wasn't even thinking about the different signals per side. I'm just used to running on RCA's. As for output being cut, why would that be? and why would the front speakers suffer, because of the "power" getting fed in multiple directions.

Ohms law.

[RamAirZ]

Ya but why would output be cut? Power is coming from the amp, signal is coming from the speaker inputs. I understand Ohms law but signal shouldn't effect the actual power output, unless I'm missing something (which very well could be)

[Bob Barker]

[tom4bren]

V=IR (Voltage = Current times Resistance).

P=VI or substitue the above equation and P=I2*R (sorry, can't superscript the 2, that's current squared).

The point of the math lesson is that power is directly proportional to resistance. If you tap into the rear speaker wires, you will change the resistance. If the powered amp has an effective resistance equal to the resistance of the rear speakers, then you will only get 1/2 of the power coming out of the rear speakers. Since it's a powered sub, you'll be able to recover the deep base but the midrange & tweet in the rear will still be lower than in the front. You can compensate for that with your fader but what you don't want to do is dork up the balance by only connecting to one rear speaker. You'll never be able to find a proper setting for balance & fader that will get the sound properly distributed.

All this theoretical minutia is happily provided by your tone deaf EE with severe tinitis. A kick arse stereo is completely wasted on me. As long as Brooks & Dunn comes in without a lot of static, I'm happy.

[Bob Barker]

I'll take your word on it and do the hard work for both speaker wires.

Thanks!

[RamAirZ]

I'll just take your word on it too because I'm looking at it from an RCA stand point. RCA's send the audio signal to the amp, the amp provides the power based on it and the subs resistance etc. Changing RCA cables wouldn't increase the power output, might get you a clearer signal path but measured output should be the same either way. In this instance I'm looking at it this way, the rear speakers output might be cut by 50% but why would the subs output be cut since it is only using those speaker wires to get audio signal and not power?

[tom4bren]

BINGO

The rear speakers will only be getting 1/2 the power that you were getting before. The powered subs will boost the power back up for it's own need ... but ... subs suck at pumping out mid to high range. You'll be getting plenty of base but you'll prolly hafta tweek up the treble a bit to compensate.

Are you starting to see why sound engineers get paid so much out in Hollyweird?

BTW, I'm not sure what you mean by RCA cables. Typically audio signals are on wires with RCA connectors and line signals are on wires with mini-phono jacks. The connectors make very little difference on resistance until you get up into VHF & UHF (i.e., shielded cables).

[etlsport]

the way this sub will have to be wired to a factory head unit is using line level input. tapping off of both rear speakers to provide a signal only, the actual power being drawn will be minimal.

normally an aftermarket head unit would have RCA terminals to provide a signal for the sole purpose of a subwoofer and the amplifier in the basslink should have rca inputs.

using line level inputs will give you sound just fine, but any distortion picked up by the factory speaker wires will be amplified too. RCA wires are shielded so they deliver a cleaner signal.

It doesnt take much power to get the signal though, most RCA signals are delivered 2v or 3v.. occasionally 5v on some nicer head units, so I don't think you are going to have a huge effect on the sound quality of the rear speakers. IIRC i think that the basslink has crossovers built in anyway, so the sub will produce NO highs or mids

[tom4bren]

RCA wires are shielded so they deliver a cleaner signal.

Not always. I've seen them as shielded, twisted pair, & twin conductor (speaker wire).

Be careful when you get a set to make sure it is shielded.

[RamAirZ]

the way this sub will have to be wired to a factory head unit is using line level input. tapping off of both rear speakers to provide a signal only, the actual power being drawn will be minimal.

normally an aftermarket head unit would have RCA terminals to provide a signal for the sole purpose of a subwoofer and the amplifier in the basslink should have rca inputs.

using line level inputs will give you sound just fine, but any distortion picked up by the factory speaker wires will be amplified too. RCA wires are shielded so they deliver a cleaner signal.

It doesnt take much power to get the signal though, most RCA signals are delivered 2v or 3v.. occasionally 5v on some nicer head units, so I don't think you are going to have a huge effect on the sound quality of the rear speakers. IIRC i think that the basslink has crossovers built in anyway, so the sub will produce NO highs or mids

exactly! That's what I was getting at. I can understand the theory of the rear speakers losing power but if they lost any it's minimal because the sub isn't using any of it technically, basically just making a longer path for the power to travel to the speakers. And yes the Basslink does have a crossover built in.

[etlsport]

Not always. I've seen them as shielded, twisted pair, & twin conductor (speaker wire).

Be careful when you get a set to make sure it is shielded.

true.. GOOD RCA cables are shielded

[tom4bren]

exactly! That's what I was getting at. I can understand the theory of the rear speakers losing power but if they lost any it's minimal because the sub isn't using any of it technically, basically just making a longer path for the power to travel to the speakers. And yes the Basslink does have a crossover built in.

You can't think of 'lectricity in that way. It travels the path of least resistance. The amount of power lost by the rear speakers is proportional to the input impedance of the power amp. If it's designed properly, it should have a very high impedance which will minimize the amount of loss to the rear speakers.

I'll refer back to my last comment in post #35 now & shut up.

BTW Eric - just rattlin yer cage Dude. Since yer so young, I didn't expect you to remember the old days when RCA connectors came on nuthin but twin conductor. Nowadays you can even drive video through "good" RCA cables.

[Ldub]

You can't think of 'lectricity in that way. It travels the path of least resistance. The amount of power lost by the rear speakers is proportional to the input impedance of the power amp. If it's designed properly, it should have a very high impedance which will minimize the amount of loss to the rear speakers.

Says the man with lightning bolts in his shorts...

[RamAirZ]

You can't think of 'lectricity in that way. It travels the path of least resistance. The amount of power lost by the rear speakers is proportional to the input impedance of the power amp. If it's designed properly, it should have a very high impedance which will minimize the amount of loss to the rear speakers.

Yes I know this, but the path would still go to the rear speakers. I'm looking at it from my experience, I never lost much if any off my interior speakers when i ran line-level converters off the rear speakers to run subs with a factory head unit.