Car Audio overhaul - [update]

[destrekor]

Update: [original post is underneath the 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:

-------------------------
[Original Post follows]
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So I'm planning on replacing the blown out and crappy Bose system in my Mazda 3. I'm leaning heavily towards either the Pioneer AVH-X3700BHS or the 2014 model, the X3600BHS as the head unit.

I think I've set my mind on the Polk DB series, the DB6501 (6.5" component system) for the front, and the DB651 (6.5" coaxial) for the rear. After much research and thought, I think I will add a lower-priced amp for the front speakers, but leave the rear speakers driven by the head unit.

I want to try and preserve a strong front soundstage, and will probably set the fade to mostly toward the front, or otherwise lower the output to the rear, if that is possible on those Pioneer HUs.

First off... does this sound like the better plan? As opposed to amping all four equally? And I was entirely leaning against an amp in the first place, but then I got to thinking, even if I don't listen loud, I should still get a cleaner and more accurate output to the speakers, at least the front speakers in this case.

Regarding amp, this is where I've got myself tripped up.

Should I focus on something simpler, like a Class D amplifier such as the Alpine KTP-445U, and bridge for two channels for 90W RMS and a far simpler setup inside?

Or should I get a more traditional Class AB two-channel amplifier?

Mind you, as much as I want to, I'm basically going to be handing this off to a professional installer. The head unit, I think, requires soldering, and in general, there are far too many wires without standard connectors. I'm not screwing around with a thousand different wire colors (mildly color deficient - I might blow something up ).

I think a unit like the KTP-445U is a simpler install. In general, I don't need a ton of control interfaces - simple gain and crossover is more than enough for when I get a moderately weak sub setup to round out the audio profile. I don't care to make a show car or blast my presence - I just want well-rounded audio that's affordable. For the moment, a sub isn't in the first stage plan, I need to spread the investment out.

 

[rommelrommel]

Personally if I was going to run rear fill I would probably amplify them.

I would not get hung up on amplifier classes... Anything decent quality at that price point is going to be more or less the same.

 

[disappoint]

Class D is more efficient on power draw, it's a car so due to potential bettery drain I 'd go with class D which is batter.

 

[halik]

I honestly don't understand spending money on audio stuff in cars in general, but especially econoboxes. It's not like the plastic interior is conducive to listening and in particular with cheap cars you get like zero sound deadening. Save your money; there's nothing good about 1000watt system rattling hard plastic interior.

 

[DaTT]

I would not run rear speakers if you don't plan on amplifying them as well

 

[The Boston Dangler]

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.

 

[disappoint]

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.

My stereo receiver has a class D amp and only class D amplification on all channels. I've had it for years.

 

[destrekor]

Personally if I was going to run rear fill I would probably amplify them.

I would not get hung up on amplifier classes... Anything decent quality at that price point is going to be more or less the same.

I would not run rear speakers if you don't plan on amplifying them as well

I figured for the lower wattage specifications that the Class D would be better. It's simpler and more efficient.

Regarding rear fill - I still haven't actually figured this part out yet. I've seen numerous people suggest if you want rear fill, get new speakers in back but otherwise focus amplifier attention on fronts only.

The intent I had in mind was to keep the audio properties of the fronts, but reduce their feed so that I'm mostly just getting more midbass fill to complement the fronts. I'd be worried about too much treble washing out the soundstage - but then again, I've always had equal fronts and rears, never added amplifiers, and never worried about soundstage. lol

As others have made a point to mention, a car like this isn't a prime listening experience, so now I'm not so sure I'm even concerned about the best sound stage. I might double-back to the original intent and run that Alpine KTP-445U in 4-channel to push 45w to all four equally. Considering the speakers have a 92dB efficiency, I'm guessing they are going to sound far too loud for my tastes prior to even reaching max clean volume on a 45w feed.

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 honestly don't understand spending money on audio stuff in cars in general, but especially econoboxes. It's not like the plastic interior is conducive to listening and in particular with cheap cars you get like zero sound deadening. Save your money; there's nothing good about 1000watt system rattling hard plastic interior.

This isn't a "significant" upgrade - not when you look at the high-end $300+/pair speakers out there, nor am I getting deluded into "1 farad capacitors" and 1500w amplifiers.

There's nothing good about the audio in the car right now. And if I only upgraded the speakers, my other main goal isn't happening: I want bluetooth integration in the car, so I can have hands-free cars routed through the speakers, and I want to stream my music through BT.


I can't upgrade the head unit without touching the speakers, considering at least one is blown out, and more importantly they are 1ohm. Running a 4ohm head unit would fry things.

I'm not trying to create a home theater or anything - but modest upgrades for clear audio seem a decent pursuit, considering I enjoy music while driving, I enjoy driving, and I have long commutes from time to time.

Who is to argue where one should enjoy their music? I fully expect my home audio system to be better than my car, but I don't want my car sounding flat and lifeless. I was satisfied with the stock speakers and a head unit on the Sebring I had. :\

I might invest in sound dampening later, as there is road noise to combat, but a decent upgrade will be pleasing, considering the audio is absolute junk in the car right now... even the speakers that don't seem blown sound like shit - this is a common complaint of the "premium Bose system", with terrible frequency management attached to cheap paper cones).

 

[Yuriman]

Go for it.

I have no specific recommendations on any components as I bought old/used parts last time I messed with audio, and a lot of them probably aren't for sale anymore. However, it made worlds of difference in my car, and I spend a lot of time there, so I was easily able to justify ~$250 for it.

My car (G1 Insight) has a deserved reputation for having the worst factory sound system of any shipping Honda. The front speakers need to be low profile and the stock head unit was terrible. There were no rear speakers. The car is aluminum and sounds very tinny without compensating with an equalizer. My solution was some low-cost aftermarket fronts with some dampening, cutting out holes and placing rear speakers, and adding a small computer/home subwoofer I snagged for free (from a Bose Companion 5 set) to bring a bit of life to the lows. I picked up a used Pioneer 640w amp to power the rears and the sub and a JVC head unit with two channel outputs in the back. I was considering a cheap Clarion equalizer, but after a few hours of tweaking I was able to get a sound I was happy with without it.

Now, when people get in my car, I usually get comments like "wow, your stereo sounds great". I think they're easily impressed, but there was definitely low-hanging fruit to be picked.

New speakers will help a lot - even just getting all of them working. You might opt for a new head unit too if you're replacing all four, don't have any factory systems tied into the stock unit (like keyless entry) and need some more inputs/outputs. I'm not a fan one line converters and mine didn't have aux in or line outs in the back. A small amp may provide an audible improvement even at moderate volume if your head unit is junk. And, if you can fit it, a small sub (emphasis on "small") can make a big difference.

I don't see much point in going with a class AB as there are much more cost effective improvements to be had before you get that far into diminishing returns.

 

[96Firebird]

I've been running a 4-channel class D amp in my Trans Am for a year now, sounds great and is very efficient considering the output. My front components and rear 6.5" subs sound great with my class D amp. They are all running at a 2ohm load. AB is great for SQ setups, but unless you have SQ drivers, you won't hear the difference between AB and D.

 

[Tuanies]

If you want simplicity, go for the KTP-445U. I had one in my Mazda 5 with the Alpine Type R components and it isn't too bad. I used it for 4-channel output. It gets louder but doesn't quite have the power on low and mid range frequencies. You can however bridge it for 2-channel output, but I never tried that. I'm running a PDR-F50 now and quite happy, but it is a bit overkill.

 

[destrekor]

I've been running a 4-channel class D amp in my Trans Am for a year now, sounds great and is very efficient considering the output. My front components and rear 6.5" subs sound great with my class D amp. They are all running at a 2ohm load. AB is great for SQ setups, but unless you have SQ drivers, you won't hear the difference between AB and D.

Rear 6.5" subs? As in ones that fit in door panels? I was looking into that option - for rear fill I mostly wanted to focus on mid bass (and lower if possible).

 

[96Firebird]

Rear 6.5" subs? As in ones that fit in door panels? I was looking into that option - for rear fill I mostly wanted to focus on mid bass (and lower if possible).

Mine don't go into door panels, and it would be hard to fit them in most door panels because they are pretty deep. Mine go in my B-pillar, you can see the open holes behind the doors in the image below. You can probably find some that will fit into your door panels, depending on how shallow you need to go. Do you plan on adding actual subs later on?

I have CDT CL-61V.2 components up front, and CDT HD-6MDVC rear subs, all wired up for 2ohm impedance running off a PPI P900.4 4-channel amp. The subs hit pretty good, but they don't go as low as I want. I have 2 subs and an amp ready to be put in, I just need to get my box finished. Winter project I guess...

Anyways, here is an image during my installation from last spring:

 

[destrekor]

Ah okay. I think I'll just keep to the coaxials in back and upgrade to a dedicated 8" sub sometime later.

 

[rommelrommel]

Class D is more efficient on power draw, it's a car so due to potential bettery drain I 'd go with class D which is batter.

This is true but a 4x40 amp ran at 4 ohm is not going to draw any meaningful amount of current. Class d really shines when you're running thousand of watts.

 

[Yuriman]

This is true but a 4x40 amp ran at 4 ohm is not going to draw any meaningful amount of current. Class d really shines when you're running thousand of watts.

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.

 

[rommelrommel]

Do you have any idea of how loud 745 watts continuous is? Average speakers are mid 90's sensitive at 1w/1m... So assuming you're putting 175 wrms at your speakers, and they can actually handle that without blowing, Music isn't a steady draw, even a 745 watt amp is usually only making a fraction of that, unless you listen to low frequency sine waves.

2w-98db
4w-101db
8w-104db
16w-107db
32w-110db
64w-113db
128w-116db
So looking at 118db or so with that kind of power, not accounting for power compression and cabin gain... Needless to say it's as loud as hell.

 

[Yuriman]

Why does anyone bother with more than a 500w amp, in that case? Does that apply to subs too? 118db is measured at what distance?

Regardless, in a hybrid where electrical load is easy to see, and the 12v battery is small and thus provides a small buffer, even a moderate amp is capable of drawing enough energy to be noticed.

 

[monkeydelmagico]

IMO, it's worthwhile to look into earbuds if you enjoying listening to it loud and drive a hybrid.

Fixed

Fairly certain most ICE vehicles drive the alternator at a fairly constant parasitic loss.

Also, aren't class D for subs and A/B for full range/component? I thought D's were not too great at full sound reproduction.

 

[Yuriman]

Fixed

Fairly certain most ICE vehicles drive the alternator at a fairly constant parasitic loss.

Also, aren't class D for subs and A/B for full range/component? I thought D's were not too great at full sound reproduction.

Alternator output varies directly with electrical load. They're almost free-spinning if you have nothing drawing power. A small car will generally have an alternator capable of ~75 amps.

 

[96Firebird]

Class D has really improved from their past, where they were only considered as sub-amps. Some are now on par with AB amps. But the old school car audio guys will stick to their roots and stay with the heavy, usually expensive AB amps.

 

[monkeydelmagico]

Got my daily dose of learning from AT garage folks. Thanks Yuriman and 96Firebird.

 

[rommelrommel]

Why does anyone bother with more than a 500w amp, in that case? Does that apply to subs too? 118db is measured at what distance?

Regardless, in a hybrid where electrical load is easy to see, and the 12v battery is small and thus provides a small buffer, even a moderate amp is capable of drawing enough energy to be noticed.

Generally people want subwoofers that play low and don't take up too much space. Basically, of small box space, output, and sensitivity, you can pick two. Most consumer grade subs have high output and work in small boxes, but are highly insensitive. Thus, they need a lot of power to have acceptable output.

Guys into high end sq will run huge amps on their front stage too, but that's about headroom and dynamics.

Generally you can run an entire upgrade system and a sub or two off of several hundred watts quite easily.

 

[bryanl]

Class D is all right for bass but sounds bad for treble, even to my non-connoisseur ears, and efficiency isn't as superior as theory indicates:

http://www.ecnmag.com/articles/2010/01/exploding-efficiency-myth-class-d-amplifiers

Rear speakers tend to be better for bass, at least with sedans.

 

[Yuriman]

Generally people want subwoofers that play low and don't take up too much space. Basically, of small box space, output, and sensitivity, you can pick two. Most consumer grade subs have high output and work in small boxes, but are highly insensitive. Thus, they need a lot of power to have acceptable output.

Guys into high end sq will run huge amps on their front stage too, but that's about headroom and dynamics.

Generally you can run an entire upgrade system and a sub or two off of several hundred watts quite easily.

Shall we meet in the middle and call it 350w? One small box insensitive sub and four 6.5's at moderately high volume, in a less than perfect enclosure, ~80% efficient amp, ~60% efficient alternator and associated wiring, and you're still looking at one horsepower.

Someone did some fun crunching to find his Corvette's cruise HP needs:

http://hamiltonianfunction.blogspot.com/2006/08/cruise-horsepower.html

I can conservatively say that 350 watts of sound will end up burning 5% of all fuel you need to propel yourself down the highway, give or take depending on the size of your vehicle.