Help! I'm overwhelmed! (And I'm a newb!)

[superdodds]

Hey all,

I've read and read and read and I'm still having trouble making sense of ohms, R.M.S., impedance, watts, and blah, blah, blah... I bought some Kicker 07CVR124 subs (qty 2) new for $100.00. I couldn't pass it up. I also scored a new Rockford Fosgate P700-1BD 700 watt amplifier for $225.00. I drive a 2006 Chevrolet Silverado 1500 pickup and my car stereo is a Sony CDX-GT520 and this has become way more involved than I ever imagined. Questions...

1.) Is this a good (or even a decent) match between my amp and my subs?

2.) Will the stock alternator be adequate enough to power this amp/subs combo?

3.) Do I need to replace/upgrade the ground strap wiring on my vehicle?

4.) Wiring this up -- Recommendations? Parallel? Series? Bridged?

At this point I plan on having this equipment professionally installed, but i'd like to have some idea as to what to tell them in how I'd like this installed. I want to assume that the person installing my gear knows what he's doing, but.... yeah, it never hurts to be informed. Thanks in advance for any help you can give.

- Dodds in San Antonio, TX

PS - I'm looking for some good speakers for my doors. 6 1/2" front door speakers and 4" rear door speakers. I'm also looking to have some tweeters installed (that are not currently part of my system). Thanks again.

Click to read more...

 

[Bettr n' Revrse 5,000+ posts]

Dont have anyone install it man we will help you out and save you a ton of money...

 

[superdodds]

Please? I'm handy enough -- I just don't quite grasp all of the electrical spec mumbo jumbo... Any help is greatly appreciated.

- Dodds

 

[GrandPrixAlpine 10+ year member]

Please? I'm handy enough -- I just don't quite grasp all of the electrical spec mumbo jumbo... Any help is greatly appreciated.
- Dodds

Dont worry i was just like you last year and started with the same stuff. just a little different brands. Let me do some research on your stuff and ill post again.

What box do you have for your truck?

 

[BnGRacing 10+ year member]

All those numbers are marketing gimmicks...in the real world they mean little.

Let me start off by asking you a question; what does a watt sound like? Even trickier; what does an ohm sound like?

...

Speakers do not have 'watts'. A watt is a unit of measurement for work performed, much like horsepower. Do the tires on your truck have a horsepower rating? No, that'd be silly. Well, speakers having wattage ratings is quite silly in the same way. The thing that'll kill a speaker is heat (or an old/dull phillips bit). How do you rate how much heat a speaker can cope with? Well, all the manufacturers have their own system while others just slap whatever number they think will move more product.

With amplifiers, the best way to figure out how much work they can perform (watts) is by looking at the fuses on the case and doing some quick math. If an amp has 2x20A fuses on it (40A), the most work it can possibly do will be around 400w. Simply add a zero to the end and you get an idea. Why a zero? Well, more math; Voltage x Current = watts. Your amp will probably only see about 13v and since amplifiers are not perfectly efficient (get warm), you can round that down to 10. So 10v * 40A = 400 watts. Forget that CEA crap and the sticker on the box.

Impedance is basically a load the amplifier sees. Think of it as one of those treadmills where you can adjust the ramp angle. A brisk walk at 4mph is a breeze right? Now adjust the angle on the treadmill. Now you're breaking a sweat. You're not going any faster, you're just being asked to perform more work to keep you stationary and not fly off the back of the treadmill. The incline is a greater load just like 2ohm is a greater load than 4ohm.

2ohm is not better than 4ohm...I'd argue the opposite actually, but that's another discussion.

...

You asked if the system is 'balanced'. Well...what does it sound like? Do you like it? If you do, it's balanced...it's really as simple as that. Do not get caught up in all the numbers & specs of 12v products as it almost never translates over to what you hear. Your ears will never lie to you, so let them make the final decision based on what they think instead of what you read on a message board or in product lit.

....

Will your charging system handle the new system? Go back to those fuses on the amp. How many and how big are they? Remember I said to add them up and basically put a zero to find the amp's power capabilities? Divide that number in half...that's the max draw the amp will have when playing music playing at 100% volume. Do you listen to the radio that loud? Probably not as deaf people don't normally shop for audio equipment.

Your charging system & factory ground strap will be more than fine for your setup. You can spend the $100 or so on battery terminals, 1/0 gauge, rings, etc and I can almost guarantee you will not hear a difference. With good power wire of adequate gauge and a proper install, there will be no problem.

As far as wiring; RTFM. Your subwoofers should have come with a basic wiring diagram for various applications (1/2/3 woofers and their various impedance). Follow that and if your subs are DVC 4ohm woofers and you basically have 2 choices on how to wire them to the amp (4ohm or 1ohm) ALWAYS go with the higher impedance. You will not make 4x the power at 1ohm than you would at 4ohm. You'll just roast something inside the amp b/c that proverbial treadmill will kick it in the groin.

Remember I said heat kills speakers? It'll kill an amp too. Just like the incline on a treadmill will make you sweat, a lower impedance does the same thing to an amp. Push it too far and it lets out the smoke.

 

[superdodds]

I've gotten pretty excited about this summer project that I had no intention of doing. My son gave me the subs for $100.00 and the amp I came across on CraigsList and just couldn't pass up. What kind of "box" do I have for my truck? I assume you mean the sub cabinet. Right now I don't. They're just 2 lonely subs waiting for a home. I was planning on building some sub boxes with ports rather than a single box. The way my truck is divided from the driveshaft creates a hump down the middle of the cab and I was thinking 2 boxes could be fit better underneath the rear bench seat than a single cabinet to hold both subs. I don't know. You tell me? I can take a photo and post it too if that helps to give you some idea of what I'm doing. Keep in mind, this really is soooo the wrong vehicle for this project but it will be fun!

 

[GrandPrixAlpine 10+ year member]

Now for your subs

07CVR124

800w Peak (the max amount of power the sub can handle)

400w RMS (the recomended amount of power to push through the sub)

To see these subs potential a 800w 2/1 amp would be ideal

Amp

Good amp for your subs. a little more power than you need but thats just fine.

Yes your truck should handle this setup well, mine did just fine with a 1000w mono on it.

You need a wiring kit too. a 1000w wiring kit is going to fit your setup the best.

Its pretty simple red to red black to black. blue is for the rem which connects to your radio.

Just remember to turn your amp down for a while to break in your subs or you will blow them.

 

[superdodds]

Hey BnGRacing - Thanks for the summary. Your explanation makes more sense to me when spoken like that. I'll do more homework tomorrow and I'll look for the manual and such for the Kicker subs online tomorrow. Unfortunately, I did not receive that when I bought these subs from my son so I'm at somewhat of an even greater loss there. As far as what the system sounds like -- I dont know yet. It's not installed. The reason I'm posting is because I want to be sure I do this "right" before I go any further. I realize now that I may have gotten off to a poor start and I'm trying to remedy that before I go any further with the purchase of other car stereo equipment. Again though, I really appreciate your explanation and will continue to head further down this road and hopefully have a killer stereo I'll enjoy for a long long time.

 

[GrandPrixAlpine 10+ year member]

I've gotten pretty excited about this summer project that I had no intention of doing. My son gave me the subs for $100.00 and the amp I came across on CraigsList and just couldn't pass up. What kind of "box" do I have for my truck? I assume you mean the sub cabinet. Right now I don't. They're just 2 lonely subs waiting for a home. I was planning on building some sub boxes with ports rather than a single box. The way my truck is divided from the driveshaft creates a hump down the middle of the cab and I was thinking 2 boxes could be fit better underneath the rear bench seat than a single cabinet to hold both subs. I don't know. You tell me? I can take a photo and post it too if that helps to give you some idea of what I'm doing. Keep in mind, this really is soooo the wrong vehicle for this project but it will be fun!

Actually they make a box that fits under the extended cab seat. thats what i had in mine. they are 150 bucks and much easier for a starter. Its going to get loud in there. i had two 10"s in mine and it was plenty.

 

[superdodds]

GrandPrixAlpine -

Wiring? Like I said, I'll look up the product manuals online to see if there is a spec for the subs but off the top of your head -- Bridged? Series? Parallel?

I'll need to look online for a box then to work in my cab. The only box I've seen is flat on the bottom and mine will need to allow for the "hump" in the middle of the cab running from front to rear...

 

[nauc 10+ year member]

impedance = a speakers electrical resistance measured in ohms

wattage = electrical power

RMS = continuous wattage/longterm power

Peak/Max Power = split second peak power

forget Peak power, you want to look at long term power (RMS power)

you want to match the amps and speakers impedance and for the most part, their wattage

and since amps usually put out more power the lower the impedance, using a lower impedance speaker gets you more wattage for your buck

example, an amp will have specs like this...

100 watts x 1 channel at 4 ohms

200 watts x 1 channel at 2 ohms

400 watts x 1 channel at 1 ohm

so if you use a 1 ohm speaker, you get 400 watts. use a 4 ohm speaker, you get 100 watts

but not all amps are stable at 1 ohm, so using a 1 ohm speaker can ruin the amp. so look at the amps specs. if it doesnt list specs at 1 ohm, its probably not stable at 1 ohm

 

[BnGRacing 10+ year member]

Now for your subs
07CVR124

800w Peak (the max amount of power the sub can handle)

400w RMS (the recomended amount of power to push through the sub)

To see these subs potential a 800w 2/1 amp would be ideal

That is all wrong. You've been lied to by PR, marketing departments, dumb salesmen, and forum experts.

You do not need an 800w amp to drive a pair of "400w" subwoofers. Why? Two reasons. Reason #1 - subwoofers do not have watts. They just do what they're told. More power just means slightly more control of the woofer at the expense of increased heat. Reason #2 - the A/C current flowing out of the 800w amp does not magically 1/2 itself when you hook up 2 drivers to it. When you want to use a lamp while watching TV, do you have to call an electrician to install 240v outlets? Do you have to turn off and unplug everything in your home when you want to vacuum the floor? No...

Subs are the same way. If you have 800w pumping thru the wires each sub will have 800w pumping through it (including each voice coil). Go test a sub out of the box with a multi-meter. Do the voltages at each coil match the voltages at the amp outputs? Of course they do. 400w subs (whether it's 1 or 4) need 400w. Doubling power when you double woofers is why a lot of people blow their stuff up.

You need a wiring kit too. a 1000w wiring kit is going to fit your setup the best.

Its pretty simple red to red black to black. blue is for the rem which connects to your radio.

Just remember to turn your amp down for a while to break in your subs or you will blow them.

Ahhh...

WIRING KITS DO NOT HAVE WATTS!!!! Does your coat hanger have watts? Why not, it's made of metal wire?

It's current you have to worry about, not watts. 12volts will barely upset you, 12amps will kill you. It's the amperage that you have to worry about. Anything up to 60A should be fine with an 8ga kit in a normal sedan and be more than enough in a truck.

 

[audioholic 5,000+ posts]

That is all wrong. You've been lied to by PR, marketing departments, dumb salesmen, and forum experts.
You do not need an 800w amp to drive a pair of "400w" subwoofers. Why? Two reasons. Reason #1 - subwoofers do not have watts. They just do what they're told. More power just means slightly more control of the woofer at the expense of increased heat. Reason #2 - the A/C current flowing out of the 800w amp does not magically 1/2 itself when you hook up 2 drivers to it. When you want to use a lamp while watching TV, do you have to call an electrician to install 240v outlets? Do you have to turn off and unplug everything in your home when you want to vacuum the floor? No...

Subs are the same way. If you have 800w pumping thru the wires each sub will have 800w pumping through it (including each voice coil). Go test a sub out of the box with a multi-meter. Do the voltages at each coil match the voltages at the amp outputs? Of course they do. 400w subs (whether it's 1 or 4) need 400w. Doubling power when you double woofers is why a lot of people blow their stuff up.

Ahhh...

WIRING KITS DO NOT HAVE WATTS!!!! Does your coat hanger have watts? Why not, it's made of metal wire?

It's current you have to worry about, not watts. 12volts will barely upset you, 12amps will kill you. It's the amperage that you have to worry about. Anything up to 60A should be fine with an 8ga kit in a normal sedan and be more than enough in a truck.

You are incorrect. If you hook 2 subs to a 1000 watt amplifier, each sub will receive 500 watts (be it wired in parallel, series, or in stereo). If what you suggest were true, we could hook 16 subs to a 1000 watt amplifier and all the sudden we have a 16,000 watt setup. That is obviously not the case.

Furthermore, power is divided among the speakers based on impedance. If you wire one 8 ohm sub and one 4 ohm sub together, the 8ohm sub will receive half the power that the 4 ohm sub does.

 

[dumple 5,000+ posts]

Check out Basic Car Audio Electronics it might become your best friend

 

[superdodds]

Um, wow... I don't even know where to begin again. This is kinda' how I wound up here in the first place. While I very much appreciate the explanation given by BnGRacing and the depth of context, keep in mind that I stated from the outset that much of this tech speak eludes me. While I understand what everybody has broken down for me, I'm not so concerned with how many watts are carried over which channels depending on how many ohms are resisitng them. If I want to stand on a ladder, I don't need to know the definition of what a pound of pressure is or what the tensile strength of steel is. I need somebody to tell me that the ladder is strong enough to hold me. When I assist a client with the purchase of a new PC or a server, they rarely care how many Ghz their processor is working at or whether it's a single or dual core -- they want their machine to be "fast" and to perform well. I now have multiple opinions conflicting with each other and I'm really no better off than I was before. I'll keep it simple.

I have (Qty 2) Kicker 07CVR124 (CVR12/4Ohm) Subwoofers. No box yet (That's a question for another discussion). Check out the specs here: http://www.kicker.com/sites/default/files/2007CompVR.pdf

I also have a Rockford Fosgate P700-BD1 amplifier. It can be seen here:

Rockford Fosgate® - P700-1bd

and the product manual can be viewed here:

http://www.kicker.com/sites/default/files/2007CompVR.pdf

Now then, without explaining how the clock works when I ask what time it is -- can somebody just tell me if this is a decent match? I'm off to a rocky start and once I get past this I can consult with those who know for other componant parts to make this a fun car stereo system to have. That's all. Thanks.

- Dodds