Car Stereos: rear door speakers, crossover circuit, chevy silverado

Question
QUESTION: I have a 2004 Chevy Silverado extended cab, the rear doors are suicide doors.I need to know what size are the speakers are in those rear doors. In the front doors my speakers are 4x6 i believe.I would like to hook these rear door speakers to my amp unless they are to small then i will use the factory speaker harness.Is this the right thing to do .I have a Pioneer 600 watt amp.The speaker cut out looks really on those suicide doors. Thanks

ANSWER: Hi William,

I think I answered part of this question a minute ago.

The front door speakers in your truck are 6-1/2".  The rear speakers are 4x6".

Generally, if you have a 2-channel amplifier and can only use it for one pair of speakers, you should choose the front speakers.  This is because the fronts will have a much bigger effect on your overall sound quality than the rears.  However, if you have a 4-channel amp, I'd certainly use it for the rear speakers as well.  It's actually a good idea to use an amplifier when you have a smaller-size speaker, because most amplifiers include a crossover circuit.  With an amplifier, you can use the high-pass crossover filter to cut the deepest bass out of the speaker.  Smaller speakers can't handle bass very well, so removing the bass before it gets to the speaker will let you play them louder with less distortion, and reduce the chance of blowing them.

Some head units also include high-pass filters, but few allow you to set the rear filter differently from the front.  Because your front speakers are larger, you'd want them to get more bass than the rears.  A 4-channel amp usually gives you this kind of flexibility; a head unit usually does not.

If your Pioneer amp is a 2-channel amp, I'd still use it on the front speakers and run the rear speakers directly from the head unit; but I'd consider buying passive "bass-blockers" to install on the rear speaker wires.

Hope this helps!

Brian



---------- FOLLOW-UP ----------

QUESTION: In response my Pioneer amp is a 4 channel amp, so with the 4x6 speakers i should run them straight from the head unit and not from the amp because of their size and their capacity not to be able to handle much bass. And finally can you recommend a decent pair of 4x6 speakers to buy.

ANSWER: William,

Sorry if I wasn't clearer--if you have a 4-channel amp, you definitely SHOULD connect the 4x6 speakers to the amplifier, rather than to the head unit.  The amplifier should have a crossover switch on it, labeled something along the lines of HPF/FUL/LPF.  For the two channels running the 4x6's, you'd want to set the switch on HPF.  This stands for "high-pass filter", and it will cut the bass out of the 4x6's.  Because of this, they'll do better with the amplifier's output than they would with the full-range output from the head unit.

There's a wide range of good 4x6" speakers--many more than I've had the opportunity to test--so don't take my recommendation as the final word.  However, I've always liked Infinity's Reference series 4x6 plate speaker.  It's constructed as a 4" round speaker with a separate tweeter, instead of an oval speaker and coaxial tweeter like most 4x6's.  

Hope this helps!

Brian

---------- FOLLOW-UP ----------

QUESTION: Hi Brain, I have one more question to ask you. I have a Sony CDX GTIPW 52x4 watt head unit and on the back of that head unit a Front Output and a Rear Output for the RCA cables.Right now i have rca cables that are plug into the front outputs that are running my front speaker (6x1/2),so should i run those front speakers that are bigger than the rears through the rear output on the head unit.And the rear speakers 4x6 should i run them through the front output on the head unit since they are smaller.Also my amp is a Pioneer 600watt 4 chanell that has a output and two inputs that are labeled input channel A,input channel B.Right now i have RCA cables plug into the output slot in the amp is that correct,or should the RCA cables be plug into the channel A input because that's where i have my front speaker wires plug into on the side where you connect your speaker wires to. Thank You

Answer
Hi William,

On the head unit, there's no difference between the front and rear outputs except for the fader adjustment.  The speaker size isn't an issue; both outputs carry exactly the same sound.  If your front speakers are connected to the A outputs on the amp, then you should have a pair of RCA cables running from the front output on the deck to the A input on the amp.  If the rear speakers are on the B outputs, then run another set of RCA cables from the deck's rear outputs to the amp's B inputs.  You shouldn't have anything connected to the amp's RCA outputs; those are used if you're adding a second amplifier (ie, for subwoofers).

Hope this helps!

Brian