OK guys,

I have (on its way) an Alpine IVA-C800.

I have a new MTX Audio Thunder 6304 4-channel amp. (see http://www.mtxaudio.com/caraudio/pro...hunder6304.cfm)

I have two MTX 12" woofers on their way.

Here's what I want to know:

How do I wire-in the subwoofer and where? I know the IVA-C800 has a subwoofer out but I assume I would not use it.

I know that the speakers work like this -- Audio Out RCA's from the IVA brain to the AMP In. Then from AMP out to the speakers.

However, what about the subwoofer? Where do I power it from the AMP? Explain this bridging stuff to me. Also there are High-Pass/Low-Pass etc switches on the Amp.

Help me I know I'm STOOPID

 

Ok assuming your amp is already installed. To gain control of your subwoofer control, (being able to control the sub volume from the ///Alpine) all you need to do is make sure the RCA coming from amp goes into the subwoofer IN on the back of your head unit.

First of all, what are you powering your speakers with, if you are at all? Are you planning on using that amp to do everything or just the subs?

Assuming you are using the MTX 4 channel for JUST your subs here is what you do. Since it is a 4 channel, you can only bridge down to 2 channels. These are two 4 ohm channels. That is, the impedence of your subs. Do you know the impedence of the 2 12s? If they are 8 ohm subs intended to be used together thus acheiving a 4 ohm load, you can only use 2 of your amp channels, and use the other two amp channels for speakers.

With two 4 ohm speakers, you will be able to use the power of the amp better. 2 Channel bridged, your MTX does about 325 watts x2. If each sub is a 4 ohm sub. All you would need to do is wire a positive from channel 1 paired with a negative from channel 2 to one sub. And a positive from channel 3 and a negative from channel 4 to the other sub. This will become clearer when you look at the MTX instruction manual.

The High pass low pass crossover basically separates frequences. If you were using the amp for subs, when you push the crossover in (Low,..I think) only low frequencies go to the subs, i.e. BASS. If you were using your amp for just speakers and you have your BASS set, you would want to select the HIGH pass filter so only highs would get to your speakers. Sometimes there is a full range setting that allows all frequencies to pass through a particular speaker. You are able to set the frequency crossover point on another dial on the side of your MTX amp. Default crossovers on MTX amps are usually set to 100hz.

 

No, the amp is not yet installed. It's sitting here on my floor. Nor is the IVA-C800. But I *do* want to be able to control the sub from the IVA.

I want to use the amp to power everything (speakers and sub).

I don't know if they are 4 or 8 ohm, I will know tomorrow. I think 4.... ?? I am not yet sure if I want to/should use both subs.

I was thinking first of using my stock speakers, wiring to them. Then I am going to buy a new set of speakers and replace the stock ones.

For now, since my head unit handles RF/LF/RR/LR I would want to do it 4-channel so I have fade/balance control from the head unit... right???

The manual really, really stinks.

The crossover lets me do highpass/lowpass/or full range on both front and rear (both front and rear have selectors).

Hearing that I want to power my stock speakers AND my new sub with the amp, how do you suggest I wire it and utilize the crossover?

Thanks for all your help man.

 

With a 4 channel amp, you can't power 4 speakers and the sub. Think of it this way, each channel on the amp will power one speaker. But there's also a catch.. bridging. In bridging, you're combining 2 channels into 1... and this in effect doubles the power for that bridged channel.
So you can mix and match what you want bridged too....
You're options are as such...
4 channels
2 channels + 1 bridged
2 bridged channels

So there's really no way you can run 4 speakers and one (or two) subs through the amp. If I were you, and I wasn't gonna add another amp, I'd do it this way:
2 channels + 1 bridged

Run your front two speakers of channels 1 and 2.
The bridged one will run the sub. The rear two speakers
will run solely off the head unit power.

Another note about the sub: you can use 1 or two off that one channel depending on the impedance of the subwoofer.
If the amp is spec'd at 4ohms per channel and you have a 4 ohm sub, you use one (and if you want to risk burning your amp then use 2). If the sub has an 8ohm impedance, you can hook them up in parallel and the overall impedance will drop to 4 ohms. Most new amps nowadays can handle 2 ohm speakers... but you're gonna have to check on yours.

In any case, good luck with the install.

If you need more help, just ask.
I'm rarely outside the 5th gen forum, but I'm sure others
such as DCmax will help you.

 

Update:

They are 12" MTX 4000 8ohm subs

Should I use one? Or both?

I am making a custom box for the trunk to hold amp, computer, and subs on top.

Do you recommend I add another Amp to power the subs?

Or maybe I should power the 4 speakers off the AMP and just power the Sub off the headunit?

Thanks again

 

It really depends on what you want to do. If you dont want to spend the money on another amp I would use 2 channels for your front two speakers, bridge the other two channels to power your subs, and run your rear speakers off your head unit (rear speakers are the least of your worries).

The only catch is, if you are building an amp rack, and want to get it right the first time, if you think you are going to want to amplify your rear speakers, it may be a better idea to just go ahead and buy another amp for your subs and use all four channels of the MTX amp for all of your speakers, so if you change your mind later, you wont have to re-do your amp rack.

MTX 4000s arent the strongest subs so if you choose to run them off 2 channels bridged on your MTX amp, 325 watts would be fine.

You have 2 8ohm subs so when you wire them in series, you will achieve a 4 ohm load which is what you want.

Oh yeah, powering any sub with a head unit is not an option.

Good Luck

 

Woah!!! Wait a sec here, powering the subs off the HU is not, I repeat not, an option. Here is what I say you do.

Front RCA and Sub RCA outputs from the 800.

Run front to channel 1 and 2 input of amp
Run sub to channel 3 and 4 input of amp

Rear speaker output from 800 to rear speakers

Channel 1 and 2 ouput of amp to front speakers.

(+) terminal of channel 3 to (+) terminal of first sub and then connect (+) terminals of the subs together
(-) terminal of channel 4 to (-) terminal of first sub and then connect (-) terminals of the subs together
(That is how you typically bridge the amplifier, check manual to be certain)

Setup the crossover for channels 1 and 2 to high pass and set it at about 100Hz or so (you can play with this, but don't go too much below 100, just my opinion)
Setup the crossocer for channels 3 and 4 to low pass and set it at about 100Hz as well (again you can play with this, but I wouldn't go much about 100, just my opinion)


Another completely different option would be to add another amp as you mentioned. You can then run the front and rear RCA's to the 4-channel amp and the sub RCA to another amp and wire accordingly. If you have questions, please post again or email me. Good luck!!!

 

Just a clarification here, wiring the 8ohm speakers in series will yield a 16ohm load. Wiring them in parallel will give you a 4ohm load. If you want the equation it is this.....

For series wiring...

R=r1+r2

For parallel...

R= 1 / ((1/r1)+(1/r2))

r1 and r2 both equal 8 so plug and chug and you get 16 for series and 4 for parallel.

This is just FYI!!

 

Yep, you are right...

Corrected again by the Dustmiester!

 

MaineI30,
I think this is the setup I posted.
also, if you're gonna do a custom trunk setup,
then add another amp for the subs as dustyroads says. The head unit doesn't deliver enough power for the subs to make any difference so you should put in another amp. For your subs, get a mono-channel amp with sufficient power. If you get a dual channel amp, get one that can be bridged. Since your subs are 8 ohms each, you'll want to use both off one channel. Running one 8ohm sub off one channel although will run the amp cooler, it won't be as loud as it can be.

 

MaineI30, jashick is right about adding the second amp. It makes a lot more sense, plus you have all your speakers being powered by your amps, much cleaner sound.

I would look into an amp that delivers about 400watts by 1 at 4ohms bridged. So if you were to stay in the MTX amps like you already have, the Thunder 8302 looks like a pretty good match for what you want to run. It'll push out 212watts per sub. That'll pound pretty darn good!! Good luck!!!

 

OK so I will buy another AMP to power the subs. I should use the pass-thru on the MTX 6304, send the signal to the sub amp, and power the subs from there??

How will I be able, in this configuration, to utilize the head unit's seperate SUBWOOFER control?

I may have someone help me with the custom box, I'm sure it'll be worth the money to have some pros do it.

I need to make the custom box MYSELF for the PC, then let the pros make the custom trunk box for amps and woofers.

thanks -- you guys rock

 

Like this: Use each channel on the 6304 to power all the speakers in your car. Do you have aftermarket speakers? If not that amp will destroy your stock speakers in matter of hours. Run an RCA from that amp to one of the RCA ins on the back of your IVA. Set the all of these channels to high pass. Crossover about 100hz +/- 10hz.

When you purchase your second amp, preferably a 2 channel, after basic installation, simply run the RCA from the sub amp to the RCA in labeled "subwoofer" on the back of the IVA. That will give you control of your sub from the head unit.

The main key for having sub control is independently wiring the RCA from the sub amp straight to the head unit. A lot of MTX 4 channel amps have whats called a "sum out" which is another RCA out that simply lets you patch a signal from that amp to another without going back to the head unit. It is tempting, but if you do that, you wont have sub control.

 

Alright .. I need time to digest this... but in the meantime, while I'm digesting, do you recommend any good aftermarket flush-mount speakers that will fit my car? And will really sing with the new setup?

thanks

 

When you say flush mount, I take it you are referring to component speaker system with a tweeter? If so, you really only need one set of component speakers and the rear speakers can just be a set of coaxials. As for the tweeters being flush...most every component system allows for this,..how comfortable are you with cutting into your door panel?

As for quality component sets...depends on your price range. Polks are solid, MB Quart, Boston Acoustics, Focal, Infinity, Alpine. Anything will be a great improvement over stock.

 

I checked out the Alpine IVA-C800 and it has
3 pairs of preamp outs… (front, rear, and sub)
The MTX 6304 should have dual rca inputs.
Each pair of rca inputs should drive 2 channels.

So as discussed by DCMAX and Dustyroads, the connections should go as such:
RCA from Alpine (Front) to MTX (channel 1 & 2)
MTX Speaker (channel 1 & 2) to front pair of component speakers
RCA from Alpine (Rear) to MTX (channel 3 & 4)
MTX Speaker (channel 3 & 4) to rear pair of speakers
RCA from Alpine (Sub) to Second Amp.
Second amp Speaker to Sub Box (2 subs wired in parallel)

The MTX 6304 also has a parallel input switch which should
Be set to off. Also you can follow the recommendations for
setting crossover points.

I drew up a quick block diagram, but can't seem to cut and paste it in here and it says the image is too big to attach as a file. If you need it, let me know and I'll email it to you.

good luck

 

jashick...you are the man!! Nice summary!! I think between the 3 of us we got this bad boy pretty much planned out. Good luck with everything MaineI30!!

 

All this stereo talk makes me want to gut my bose and install a brand new system... damn

 

Tell me about it!! Right now my girlfriend has a better system than me!!! Ahhh!! It's making me crazy!! I just need a HU and some subs and my system is going in. I'll let you all know more later!!

 

No what I was getting at is ones that will easily swap out with the stocks, and mount in the stock brackets in the doors, so I didn't have to cut, etc.

I may have pros do it, I'm getting nervous...