5.1 surround rear channel question

Mal'ak Nephel · 04-11-2006, 04:53 PM

I am in the process of building a 5.1 system. I have the option of running about 55W or 80W to my rear speakers (2 alpine type R 6 1/2). Running 80W will cost me about 2X as much for the amp. I have lots of experience with car audio but have never run a 5.1 system.

I could use some input on how important the rear channels are with surround sound. While sound quality is important to me I do not wish to spend way more for little or no gain.

3onDubs · 04-11-2006, 05:00 PM

For accurate surround sound reproduction...your going to need 4 of the exact same speakers, one center speaker, and a sub. The sound behind you will be weak and it won't sound accurate.

How important is this to you honestly? Do you plan on heating up popcorn and sitting in your car? I've had a surround sound processor for months now and i've never used it once....to me, music sound quality is more important. I'd understand if you plan on fabbing a Plasma in your dash and you wanted the sound to match the visual sensation of a big screen two feet from your face, but a little 7" screen won't make you feel that the sounds are struggling.

Bob_Barker · 04-11-2006, 05:36 PM

If you are planning on putting the 42" plasma in dash then go for the bigger amp because you will have to sit in the back seat to watch your movies. Are you planning on mounting a full size speaker in the dash as well?

If your primary use is going to be sq (and have the 5.1 for the coolness factor & the occasional movie) then spend the extra bucks on your front stage and let the poor sob's in the back seat deal with the lesser powered speakers.

Mal'ak Nephel · 04-11-2006, 06:07 PM

Here is more info on my system once finished:
1000WX1 12" Sub
80WX4 6.5" Mid-bass (front)
55WX2 4" Mids (front) or 80W
55WX2 1" Tweeters (front)
55WX1 5.25" Mid (center)
55WX1 1" Tweeter (center)
55Wx2 6.5" components (rear) or 80W

As you may guess I am trying to decide between a 80WX4 (about $300-400) amp or a 55WX4 (about $130).
While I am sure my front mids do not need 80W I have little experience with a 5.1 system and do not know the benifits of running more power to the rears.
My head unit will be my carputer runing a fiber optic to Alpines PXA-H701 processor.
I am looking to enjoy some benifits from upmixing stereo music and also listen to 5.1 music videos aside from dvds. I can imagine a 8" screen would seem rediculous with a larger stereo.

Thanks for the help so far, I was surprised how fast I received a response!

Bob_Barker · 04-11-2006, 06:59 PM

Just noticed you drive a Mustang. I am still voting for the smaller amp for the rear set. I just don't think they are going to make a difference, espicially in such a small space. Have you considered a phantom center yet? it could save you some $$ and heartache with the tuning process. ~Bob

nkotch · 04-11-2006, 07:10 PM

For that price difference I'd probably go with the smaller amp, it'll still be good sound since you're using good components.... just make sure the speakers are fine with whatever power you do give them. You could always turn up the surround level to compensate. Plus, a car is not an ideal place for surround sound anywhere so spending an extra $200 on a higher powered amp just for those isn't go to gain you a whole lot.... in my opinion.

In home systems the center channel is really the most important speaker...and that's where most people go cheap on....just something to think about. In the car though, it may be worth seeing how it sounds just doing phantom center and using just the two fronts.

Installed plenty of high end home theaters but haven't been in a car with 5.1 yet let us know how it turns out!

Mal'ak Nephel · 04-11-2006, 10:52 PM

Smaller amp it is. I already have the rear speakers so I might as well install them and see how it works with a phantom center. Later I will instal a real center and see what the difference is.

If nothing else I can say I have a 15 speaker system

....

Thanks again for your input

3onDubs · 04-12-2006, 10:56 AM

Did you plan out your sound stage at all, or are you not going for an accurate 5.1 surround stage?

Either way, you're doing it all wrong.

Are you running a a 3 way component set along with an extra pair of midbass's? No matter what you do, your not going to get accurate 5.1 surround sound.....the speakers are way to close to eachother....your actually just going to get a bunch of noise, but the noise from the front is going to overpower the noise from the rear, but there's still going to be noise all around you and you will lose the sense of "direction" that 5.1 provides.

If your going for a proper front sound stage (i.e. sound quality is important to you)...then, well...don't really have that either.

Have you ever seen someone overdo something? Like, you watch them work on a project, and you look at it and you think it's done, but the person working on it wants to keep doing more, and they end up ruining it....this is kinda like that...keep it simple and it will sound 10X better. Build a front stage, add rear fill, keep your dash in one piece, and get much better sq.

Mal'ak Nephel · 04-12-2006, 11:46 AM

Hmm I am not going to lie the 5.1 is an after thought. If I am going to run a processor any way why not run 4.1. The extra cost is very low to add the rear speakers so I might as well make the mistake and learn from it. On the other hand, if I like the sound I will consider adding a center.

As for the front stage the problem I see with it is running four mid-bass speakers which I only plan to do if I am disapointed with two.

Rear fill is generaly a way to compensate for a poor front staging and to entertain your back seat passengers. Course my passengers won't care how entertained they are cramed in the back of a mustang. Not that I am trying to argue, that is just my 2 cents based on my own experience.

Asside from all that thanks for your input I am definiately going to do a little at a time and see what happens. I will probably do more research on surround too, sounds like I need to

3onDubs · 04-12-2006, 04:54 PM

I had a 2001 mustang before my car right now....and let me tell you, that thing was LOUD. Those cars are soooo perfect for bass it's ridiculous. I put two crappy tens in the trunk for my first system and that thing sounded like it had a pair of quality twelves.

You don't need 4 midbass's...just 2 quality ones that will blow you away. No matter how many you add...you can't beat the clarity and loudness of a high quality set. If you think that there doesn't exist a component set on the market that will satisfy you...then you are terribly wrong. If it's the loudness that your going for...get a pair of horns and get rid of the tweets (ur ears will bleed).

Let me ask you a serious question. According to your current daily schedule and regular life....how often do you feel that you are going to take advantage of a 5.1 experience in your car?

Now let me ask you another serious question. According to your current daily schedule and regular life...how often do you feel that you are going to take advantage of listening to music in your car?

My advice: Take those answers and invest accordingly.

Mal'ak Nephel · 04-12-2006, 09:38 PM

Your right, the effort compared to the end benefit is really not worth it. I can imagine already what it takes to tune a 5.1 system. Really at best all I am going to get out of it is a few lowsy hours of surround till the novelty wears off.

As for how often I take advantage of listening to music in my car ... well probably too much but I won't get into that

3onDubs · 04-13-2006, 11:49 AM

The only reason i don't think it's a good idea is because you're going to do all of that work....probably fab in a center speaker...watch one movie...and then realize that this was probably the last movie you'll ever watch in your car.

Music on the other hand....if you can get that to sound good, you know your movies are going to sound good as well. Personally, i'd rather watch a movie on two high quality speakers than 5 lower quality ones.

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