Seeking input on sub and amp

I need help picking an amp and sub for my 2010 Access Cab. I have a little knowledge of car audio, but not much so I turn to this board for recommendations. Here is what I have so far (not installed yet)...

Kenwood DNX7140 Head Unit
Kenwood KFC-P708 6-3/4" 2-way Component System 65 Watts RMS (not the best, but they were 55bux from Crutchfield so I figured I'd try them)

I would like to get an amp and bridge it to 3 channels and the amp must fit under a seat. Also, I live in TX, so it will get hot as hell in in the cab at times (not sure if this makes a difference). I was looking at a MB Quart FX4.100 but again, I'm not sure it will fit under a seat. I am also open to suggestions on others...

As far as the sub goes, I will get either subthumps downfire, or Mr Marv's rear console replacement sub box. As far as the speaker, I really don't know where to go on this one.

I'm looking to spend $300 MAX on just the sub and amp and I know that the box will be extra. I'm not looking to rattle houses with it, I just want it to sound good in the cab for the many road trips that I take.

TYIA!

 

Why not run the components off the headunit and run the sub off a dedicated class D amp?

 

$300 is really not enough to do what you want to do, your radio is really 15 watts per channel no matter what it says. A multi channel amp is a good consideration for what you want, don't go cheap. When it comes to stereos you get what you pay for, you can go cheaper if you are a savy ebay shopper. Save up and plan it out if you do not have the money now. It took me 2 years to build my $5K stereo system, it was worth it.

 

I have been told that the head unit would not be enough to push the front speakers because they are components?

 

Oh, I hear ya, and I'm sure that you have a really sweet setup. But all I want is some deceint sounding tunes that will not break the bank. Right now, I have $700 in the headunit and 55 in the speakers. Looking at around 150 for the amp and 150 for a speaker. Then the box and installation...

 

Exactly. Its a terrible idea.

About 1.5-1.7k in my system. I love it.


I agree with having a separate sub amp tho. leaves more room to grow.

 

That's just it, I don't want to grow from this initial setup. I'm not too much of an audiophile and just want it to be better than stock. Hell, I'm going to be listening to MP3's on it, if I were that concerned, It'd be wav files or better. I appreciate that you guys get/want nothing but the best, but again, as long as it sounds "good" to me and doesn't cut out then I am OK with it.

 

kicker,alpine,JL audio,hiphonics, those are some good brands for amps and speakers but for your sub i would run an exile sub a little more spendy than your average 10 or 12 but well worth it, get you some good component speakers like kicker ect. and dont skimp on the amp wiring, spend a good bit of penny on that and get you a box built of find one that will match your sub/s perfectly and youll be thuggin before you know it

 

We have a lot of miss-information going on in this thread so let me set the record straight.

The power your headunit will put out is fine. Anyone who says you NEED a certain amount of power to run a speaker is either a liar or doesn't know what they're talking about. Now, if they tell you that you'll need X amount of power to reach a certain decibel (sound) level, they actually know what's up.

The components you're looking at have an efficiency rating of 91db which is actually pretty darn high. That means they will produce 91db of sound when fed 1watt of power. Think about that. Do you have any idea how loud 91db is? It's a normal listening level that you'd have to speak up to have a conversation with someone next to you. This is with 1 watt of power. Double the power to 2watts and now you've reached 94db, 4watts for 97db, and a whopping 8 watts to crack the 100db mark.

So in short, unless you listen to music REALLY loud you really don't NEED an amp for the components.

Run them off the headunit with a crossover (on the headunit) set to 80hz HPF (high pass frequency). The, buy a sub amp and set the crossover to 80hz LPF (low pass frequency). You can change these settings to your taste but I recommend these as a very good starting point. Setting the crossovers this way will help take the load off the component set and they won't need as much power.

Fred, you're in the DFW. Maybe we should meet up so you can have a listen to what I've got in my truck.

 

PS: I have a small amplifier at home that makes 10watts of power into 2 channels. If I maxed that out on my home towers you'd shit yourself. Power is only half the equation, the other half is efficiency.

 

Truth. Seems to be missing in a few other posts...

Again, truth.
But that efficiency, with a crossover, seems too high. Lets say its rated at 2.83v instead of 1w/1m. Even then, 16w to break 100db.

And like you said, that is loud. The general noise floor for most cars is around 70db at cruising speed. That is a lot of volume.

Dont most people average volume around 85-90db?

Great recommendation. Also keep in mind that you can get a nice, efficient sub, and a lower powered amp. IF you decide you want to amp the speakers you can always add a 4 channel and run components + sub bridged off the rear.

Or add a 5 channel or 3 channel, etc.

Truth. But its fun to try...

 

Sweet man, thanks for clearing that up, I was getting a little frustrated there. In reading your posts on this board (past couple of months) and with my somewhat limited knowledge of car audio, I do value your input. I guess the 8" door speakers never worked out?

I have no problem just getting a sub amp and powering the speakers off the stereo as that is what I have done in past truck, but I also didn't have components. I might take you up on your offer as I am in the east Dallas area. I'll probably PM you for some more advice if you don't mind.

 

Yeah, I was thinking it was high and likely rated at 2.83v but then again most manufacturers do that regardless. And as far as component sets go that's still fairly good.

As long as he's not asking 50hz> out of them I don't really see him needing an amp.

 

I'm not a fan of clipping either. But remember, clipping only happens when you EXCEED the rated power of the amp by turning the volume up too far.

And can you explain what a "high current" amp is? I'm really curious what that is and how it works. My little 10 watt amp isn't "high current". In fact, it will run off AA batteries.

 

The 8" component set didn't work out because we were fighting too many variables. The depth of the doors made it tough and finding something efficient enough made it even harder. I'm still keeping an eye out for things. I might try again if something good pops up that might work.

 

Once upon a time I was broke and picked up a Sony amp for next to nothing. This was right after they started investing in car audio with bright colors instead of bright engineers.

Anyway, on the bottom of the amp (inaccessible after install) there was a switch that was labeled "High Current". For the life of me I can't remember what they claimed it did (or if it actually did anything), but I am 100% certain there was a switch.

 

A lot of manufacturers have, at one time, labeled something "high current". It doesn't mean anything though. It's pretty much a marketing term. A member on another board put it best...

Essentially, watts (power) is the metric you're after. If your speaker impedance is high you don't need as many amps (current) but if the impedance is low the amps (current) must be even higher to sustain the same power (watts) level.