Car Audio overhaul - [update]

[SparkyJJO]

Fun bit of math:

1 horsepower = ~745 watts

Car alternators are generally something like 50-75% efficient, so you're looking at having a 2 horsepower load on your engine if you're blasting 700 watts.

2HP doesn't sound like much, but most econoboxes take something like 15-25HP to cruise on the highway. Drawing 700w on the highway will often equate to a 10% or larger increase in fuel consumption, which is around 3mpg in your typical small car.

The average American drives ~15,000 miles per year, so the cost of running a ~700w car stereo over one year (worst case, assuming you're using it all the time over those miles) is about $175 per year. Double that if you're at 1500w.

Why did I bother to look this up? Really cranking up the stereo (~700 watts) in my hybrid causes a "forced regen" where the electric motor is constantly doing the equivalent of a mild regenerative braking. It's actually more efficient than an alternator, which would be doing the same thing, but even so it causes a small but noticeable impact on performance (a bit less than turning on the A/C) and a bigger impact on economy - 5+mpg off the top.

IMO, it's worthwhile to look into efficient sound equipment if you enjoying listening to it loud.

EDIT: Doesn't take into account the efficiency of an amp. If they're 80% efficient, you can add an extra 25% draw.

You do realize that you really aren't drawing 700W continuous or even close to that, so that theoretical mpg loss really doesn't apply, right? If you really were doing that I'd expect you're totally deaf.

 

[Yuriman]

You do realize that you really aren't drawing 700W continuous or even close to that, so that theoretical mpg loss really doesn't apply, right? If you really were doing that I'd expect you're totally deaf.

How loud is 350 watts (or, 700 for that matter) split between 4 moderate to high impedance speakers (for a car), and an inefficient sub?

I suppose it depends on what you're playing, of course, but I've found even small subs can really eat watts without getting all that loud.

Anyway, I digress, and I'll quit this tangent. It's just something I like to think about from all angles. My vote is that OP goes for the amp and sub, but go for the more efficient parts. Class D will probably sound better than being amplified by the head unit regardless.

 

[rommelrommel]

I guess the question is, do you listen to sine waves?

Music isn't even close to continuous, to some extent it's analagous to an car engine... sure a LS7 makes 500hp but only when you're revving it out.

Class D and other switching amplifiers are more efficient than class A/B, just as that is more efficient than class A. However, I really doubt your average 2/3/4/5 channel amp playing music at average listening levels draws enough on average to effect your mileage much.

 

[destrekor]

Well, the parts are ordered.
Pioneer ACH-X3700BHS head unit
Polk DB-6501 in front, DB-651 in rear.
Alpine KTP-445U 4-channel amp which will power all four speakers equally (45w RMS is more than I've ever had in car speakers - and I've never maxed audio, though my last
also ordered Metra's dash kit, wiring harness, and adapter for steering wheel controls.

Long term plans:
Adding a decent amp and sub to even out the frequency spectrum (I don't need to be heard across the parking lot - I'd just like to not have flat audio. Modesty is my audio approach).
Dampening is a maybe: I'll have to hear what all this sounds like first. Some basic dampening simply surrounding the speakers may be sufficient if my research is accurate.

 

[destrekor]

Something I may have forgot:

Do I need speaker adapters/harnesses? That piece that interfaces between vehicle wiring and aftermarket speakers? Or, can the wire just get directly connected, soldered perhaps?

 

[Yuriman]

You'll need a harness, but you could make something for the speakers if the stock ones don't use spade connectors. Adapters for those are usually dirt cheap on Amazon though, so I'd consider both.

 

[Scarpozzi]

significant car audio upgrades are a complete waste of time and money, as cars have terrible acoustic properties. swap out the crap factory speakers and you'll achieve most of the improvement possible.

if you add a sub, you'll certainly need an amp. not all amps can be bridged, so verify the model before committing. remember, it's always safer to up in resistance (ohms). class d amps being used for anything but subs is a new one to me.

I agree. If you shoot for moderately priced speakers that don't have paper cones and verify that they are connected properly, you'll minimize buzz and static. You can do this for very little money as even new low-end speakers are sometimes made very well these days.

If you insist on adding a sub, it won't take much of one to achieve substantial improvement in audio...just having one beyond the standard 6.5s can make a difference, but you may be better off just going with a passive Bazooka unless you just want to be annoying to your neighbors.

http://wwv.crutchfield.com/p_204BT6...32465&awat=pla&awnw=g&awcr=47439085705&awdv=c

I used to run a pair of Kicker 12s in my car with a pair of amps. They were loud and even made non-bass music sound better, but that's only when they were turned down. Most music doesn't need substantial bass to make a big difference. If the output of your factory deck isn't enough, upgrade it....but you may want to weigh the cost of going with a more powerful deck + passive sub versus simply adding an amp and a real sub.

Just remember, it's nice to be able to remove the sub later easily when you realize you want your money back.

 

[destrekor]

You'll need a harness, but you could make something for the speakers if the stock ones don't use spade connectors. Adapters for those are usually dirt cheap on Amazon though, so I'd consider both.

Well the radio harness I have ordered.
I was referring to these:http://www.metraonline.com/part/72-5600
(I had previously seen them labeled as speaker harnesses as well as speaker adapters, pardon my confusion)

Metra says those are the ones I need for my Mazda3, and considering much is shared with Ford in those generations, I don't doubt it.

I'm trying to figure out how the Bose tweeters are wired. With the component system, I'm just taking the feed from the amp and connecting that straight to the crossover that will be mounted in the door, and simple spade wiring serves to connect the woofer and tweeter to the crossover. For the Bose system, I have no idea how that is handled. I think I have heard it uses a direct connection to the woofer and simply has a high-pass filter as a crude crossover built in, which should mean the factory wiring is a straight two-wire link instead of some convoluted four-wire feed. I hope I have that right.

 

[96Firebird]

I'm gonna do a little critiquing because that's what I do... 😀

The 6501s are probably gonna want a little more power than 45WRMS. They will still get loud, but will really shine with an amp rated at 80+WRMS. Looks like you already have everything ordered, so food for thought I guess...

The power pack is a unique amp because it is designed with speaker wires attached. They look like 16AWG wires, which are good enough for the output it is rated at. However, I can't really tell how long they are. The owners manual doesn't help any, either. Crutchfield says 30" speaker wires, which seems really short to me. Unless they expect you to cut into the existing speaker wire behind the dash...

Reading this installation post, it seems like you indeed do need to cut the existing speaker wires from the stock harness. I never like cutting factory wires like that, but to each their own.

You'll need to pick up some RCA cables. Looks like both the head unit and power pack are female, so you'll need 4 male to male cables.

Everything else should be included, although I'm still not positive on how the power pack is installed. That may need another harness to prevent cutting, but I'm not sure.

Edit - Ah, I think I see how it is supposed to be connected. Looks like the speaker wires from the power pack connect to the wiring harness bought that connects to your vehicle's wiring harness. So don't hook those up to the head unit's speaker wires.

 

[destrekor]

Update:

This is in regards to the Alpine KTP-445U power pack/mini amp.

It is designed to be connected to the power circuit feeding the head unit. It really needs a 15A dedicated circuit (it is capable of 4x45w, or 2x90w), but they push the idea of sharing the head unit's power feed, so long as that circuit has a 15A or greater fuse.

I don't trust that concept, at least, not to get the fullest power possible. I'd rather go that route, considering it's easier and I'd rather not get insanely involved in wiring all of this up (I am going to attempt to tackle this myself).

The amp has a 15A fuse. My head unit that is going into the system has a 10A fuse.
According to the owners manual, this is the audio fuse:
AUDIO
30A
Audio system
(BOSE Sound System-equipped model)

I will be cutting out the Bose amp from the picture, and my new head unit has a 10A fuse.
Does that make it an easy decision for me to go ahead and just connect the puny power wire from the amp and use a crimp connect between that and a power connection... somewhere?

This is from the manual for the amp:

Battery Lead (Yellow)
There are two options:
a. Connect battery lead to OEM radio fused circuit
The OEM radio circuit has a fuse to protect your
vehicle's electrical system in case of a short circuit. Do
not connect the battery lead to the OEM radio circuit if
the fuse rating is less than 15A.
b. Connect battery lead directly to BATT+
Be sure to add a 15A fuse (sold separately) as close as
possible to the battery's ( +) terminal.

Once I have everything out of the packaging, all of the panels are removed, and the OEM unit is disconnected, I might have a better idea... but right now, I don't know just where that connects.

I do have an 8ga amp kit I bought, but I'm also confused how I'd even connect that to the amp. It doesn't use ring terminals or anything... I'd simply have to connect the 8ga wire to this puny little yellow wire (the kit has a 50A in-line fuse near the battery connection). Would I cut that amp-end and just use a large crimp connector to connect the two? Something sounds possibly dangerous with that idea.

I can handle speaker and networking wires... but dammit, I've tried very hard to stay away from raw electrical lines. I like my tidy consumer-friendly power cords. Less scary and lethal, they are. :awe:


Edit:
Uh... change of plans?

I just found this in the owners manual, a fuse in the passenger side fuse box, under the glovebox:
RADIO
7.5A
Audio system

I am curious about my head unit having a 10A fuse, whereas the radio circuit is apparently only protected by a 7.5A fuse.

I'm thinking I could entirely remove the Bose amp under the driver's seat, and tap into the power feed there, for that 30A protection? I'd have to cut off the OEM amp harness, but that was sort of the plan anyway, as I was going to splice the speaker wires on both sides of the amp (oem radio used speaker-level connections between radio and amp). And a handy bolt to ground to is conveniently located as well. I'd just have to use RCA cables between the head unit and under the seat, through the center console. A few pictures I've seen make this out to be not that troublesome - save for the unbolting of a seat and disconnecting the SRS airbag cable attached to said seat. 😱

 

[ummduh]

Your amp needs power directly from the battery. Don't hook it up anywhere else.

Ever amp I've ever seen has had set screw style retention systems. You strip 3/8ths of an inch or so from the wire, insert it into the block and tighten the set screw to retain the wire.

The amp power wire needs to be fused AS CLOSE TO THE BATTERY AS POSSIBLE. I emphasize this as a lot of people put it wherever, and that's a dangerous mistake. The fuse protects the wire, not the amp. The less unfused wire you have, the better.


Edit, looked up what amp you are using.

It looks like the unit has its own 15A fuse. In that case, your 8GA am wire kit is massive overkill. You could use 12GA wire up to a 10 foot run, or 10GA wire up to about 15 feet long. You still need a fuse at the battery, again, the fuse is for the wire, not the amp.

Just use butt connectors ( I use uninsulated, then solder them, then heat shrink), but there tons of options out there. Just make sure it's secure.

I'd also run a ground from the stereo head unit case to the same place you ground the amp. Tends to help reduce /prevent ground noise.

 

[destrekor]

Your amp needs power directly from the battery. Don't hook it up anywhere else.

Ever amp I've ever seen has had set screw style retention systems. You strip 3/8ths of an inch or so from the wire, insert it into the block and tighten the set screw to retain the wire.

The amp power wire needs to be fused AS CLOSE TO THE BATTERY AS POSSIBLE. I emphasize this as a lot of people put it wherever, and that's a dangerous mistake. The fuse protects the wire, not the amp. The less unfused wire you have, the better.


Edit, looked up what amp you are using.

It looks like the unit has its own 15A fuse. In that case, your 8GA am wire kit is massive overkill. You could use 12GA wire up to a 10 foot run, or 10GA wire up to about 15 feet long. You still need a fuse at the battery, again, the fuse is for the wire, not the amp.

I'd also run a ground from the stereo head unit case to the same place you ground the amp. Tends to help reduce /prevent ground noise.

I knew 8ga was overkill, that said, I couldn't find anything locally that was smaller. And with cheap kits, I also figured the claimed 8ga was actually closer to 10 or 12ga in electrical conduit in the center with a thicker jacket. Some cheap brands are very much like that, though I have no idea of the Scosche brand's reputation for gauging accuracy.


That said, I've decided for the puny 15A amp, the stock wiring dedicated to a very similar setup is sufficient. The head unit has its own fuse, while the Bose system (amp + wimpy "sub" woofer) is on a dedicated 30A fused circuit. I'll be tapping that power feed, as that circuit is suitably protected with the 30A fuse. I'll run a dedicated ground to the chassis using one of the bolts that holds down the Bose amp mounting plate. Though, I have been debating between the dedicated ground (as always instructed) and utilizing the "chassis ground" wire that the other electronics use. Common ground is good ground, as you say. I've dealt with ground loops in home electronics, and I'd like to avoid them here.

A lot of what is happening here is only something I'd ever consider for such a small amp as the KTP-445U. If I were wiring up a dedicated mono or bridged 2-channel for the subwoofer I'd like to install probably a year from now, then absolutely, I wouldn't consider anything other than a dedicated battery run, matched gauge grounding, etc. But for this, I'm essentially creating a more perfect factory amp setup - swapping out the Bose amp under the driver seat for an amp that isn't aggressively powered but a small boost. I wouldn't doubt if that Bose amp utilized just as much energy as this Alpine power pack. Heck, it was probably super low sensitivity yet claimed higher wattage... though I have never seen any reference to watts per channel for the factory amp.

 

[96Firebird]

So I'm confused, did you get it hooked up yet? Did you replace your stock amp?

8AWG is probably overkill for your setup, but too big is better than too small. I have OFC 0AWG run from my battery to the back, then split into 2x 4AWG running to both amps. I've yet to install my sub amp, but I'll get around to it eventually...

 

[destrekor]

So I'm confused, did you get it hooked up yet? Did you replace your stock amp?

8AWG is probably overkill for your setup, but too big is better than too small. I have OFC 0AWG run from my battery to the back, then split into 2x 4AWG running to both amps. I've yet to install my sub amp, but I'll get around to it eventually...

Not yet - I stumble onto roadblocks almost every step of the way with the front speakers alone. And snow interrupted me this afternoon, and then it was too dark to continue.

I've got the head unit harnesses (metra harness, pioneer harness, and the steering wheel control interface harness) laid out and I think I've cracked that code. I also just a few minutes ago moved two pins on the metra harness so that I could properly connect the steering wheel adapter, and those two pins/wires wouldn't be used anyway.

I do wish I had a sure-fire way to know which wires were what on the Pioneer harness. They appear to use a standard color code, but as usual, the pigment shades that Metra uses are different from that of the Pioneer harness.

I can determine which wires I don't even need to bother with on the metra harness based on their position, thanks to finding a few pinouts for the oem harness. The Pioneer harness, for now, is just a jumble of cables. Some colors are obvious, like black, red, yellow, and a few of the speaker pairs that I will ignore stand out, like the white and white/black pair, or whatever it is. I think the blues are for remote turn on, which I won't be wiring up.

Damn this world. In a world where game designers include color blind UI modes, manufacturers still create lists with "this function = this color" and that's it - diagrams of the pinout on both harnesses and I can match things up perfectly. Argh.

Hopefully I can finish the speakers tomorrow before the OSU game, and after, I hope I can tackle at least the amp under the seat.

I'm handling this in reverse so that I can still have a functioning but crippled system if some steps take too long or I hit major roadblocks. If I installed the head unit first, I'd have to disconnect the stock amp and be left without any audio, as they are 2ohm or 1ohm speakers, and a 1ohm "bass unit" - a 4ohm head unit driving all that wouldn't be pretty I think. The unit as is appears to be happy driving the 1 4ohm speaker I do currently have installed.

I can't wait to really hear the whole setup I have planned. I'm not used to hearing good car audio with tweeters at ear level - and frankly, when I faded and balanced the audio to only the one component speaker I had installed, it almost sounded off it was so new. The tweeter could be angled better, but it's missing the twin to complete the imaging, and it's driven by equipment without fine frequency control and good clean processing, so I cannot judge it yet - but it was remarkably better than the stock system even as it stands now. 😀

The Polk DB6501 and 651 are advertised to be capable of hitting 35Hz, and I must say, it was a very pleasing woofer - and I hear the frequency handling below below 300Hz on this stock setup is miserable, and of course the power delivered to these speakers is terrible right now. Can't wait to open them up a bit!

And of course the 6501 pair could be more happy toward its peak RMS, but at least the rear pair will be getting comfortably close to its 60 or 65W RMS rating.

 

[ummduh]

Well, this seems like a dead simple install.

The only wires you need from the Pioneer harness are Power, Acc, ground, and remote. Yellow, Red, black, blue/white.

Hook up the amp via the RCA outs.

Either run the speaker outs from the amp back to the Metra harness, or pull new wires. I wouldn't run 45WRMS through factory wiring. IMO. And since you're dealing with bypassing a factory Bose system, I'd just pull some new wires and bypass it all.

The metra harness is always labeled on the wires themselves as to what their function is.

And according to the manual, its 2 ohm stable. I know Bose tends to do some GOOFY stuff with their components, so I have no idea what yours are.