Help with bridging my amp for my components

[nags 10+ year member]

I've got an Arc X2 850.5 Amplifier powering a set of Hertz MPK 163.5 PRO's in the front and a set of Hertz MPX 690.3 PRO's in the back. I think I'm underpowering both of these and would like to bridge the amp to just power the 163.5's and eliminate the 690.3's in the back. I understand I use the positive and negative from 1/2 and 3/4 combined to go out to the front speakers. But I'm unsure what to do with the RCA inputs on the amp. I've included links to everything below;


Amp;

X2 SERIES AMPLIFIERS | ARC AUDIO

The X2 Amplifier Series has been refined to offer users the highest level of clean and effortless power production possible.

www.arcaudio.com

Hertz MPK 163.5 PRO;

Hertz car audio systems | The Sound Experience

Hertz produces high-performance car audio systems driven by research: V-cone®, Boundary Free Surround Tetolon Fibre, Rotary High Frequency Contour

www.hertzaudiovideo.com

Hertz MPX 690.3 PRO;

MPX 690.3 PRO - Hertz car audio systems | The Sound Experience

The three-way MPX 690.3 car audio coaxial, optimized for rear deck mount, features a 28 mm Tetolon tweeter with Neodymium magnet and faceplate profile maximizing the off-axis dispersion.

www.hertzaudiovideo.com

Click to read more...

 

[marc2112 10+ year member]

I've got an Arc X2 850.5 Amplifier powering a set of Hertz MPK 163.5 PRO's in the front and a set of Hertz MPX 690.3 PRO's in the back. I think I'm underpowering both of these and would like to bridge the amp to just power the 163.5's and eliminate the 690.3's in the back. I understand I use the positive and negative from 1/2 and 3/4 combined to go out to the front speakers. But I'm unsure what to do with the RCA inputs on the amp. I've included links to everything below;


Amp;

X2 SERIES AMPLIFIERS | ARC AUDIO

The X2 Amplifier Series has been refined to offer users the highest level of clean and effortless power production possible.

www.arcaudio.com

Hertz MPK 163.5 PRO;

Hertz car audio systems | The Sound Experience

Hertz produces high-performance car audio systems driven by research: V-cone®, Boundary Free Surround Tetolon Fibre, Rotary High Frequency Contour

www.hertzaudiovideo.com

Hertz MPX 690.3 PRO;

MPX 690.3 PRO - Hertz car audio systems | The Sound Experience

The three-way MPX 690.3 car audio coaxial, optimized for rear deck mount, features a 28 mm Tetolon tweeter with Neodymium magnet and faceplate profile maximizing the off-axis dispersion.

www.hertzaudiovideo.com

View attachment 31815

 

[nags 10+ year member]

View attachment 31817

What about the RCA inputs from the head unit? That's the part I'm not sure about.

 

[Kickstand Premium Member]

They don't change
Just leave them where they are
Just an FYI
You will now be running at 2 ohms on an amp that states 4 ohms for bridged
On a front end setup it won't matter or do any harm
Just be careful if you start doing it with subs

 

[nags 10+ year member]

They don't change
Just leave them where they are
Just an FYI
You will now be running at 2 ohms on an amp that states 4 ohms for bridged
On a front end setup it won't matter or do any harm
Just be careful if you start doing it with subs

So it wouldn't be 250x2 @ 4 ohms? That's what I'm going for....I think.

 

[Buck 5,000+ posts]

Your amp should have a manual to show how to bridge exactly. That’s the easiest way; because you can just copy.

Usually 1/2 and 3/4 are front/rear. In this case, you 1/2 is left and 3/4 is right side. So if your amp has 2 sets of RCA’s, then you’d want your left side signal going to 1/2 and your right side signal going to 3/4.

 

[Buck 5,000+ posts]

So you want to make sure that the amp has the correct left/right RCA’s signaling the correct channels. If you can find the amp manual and post it up, I can look at it. You can send it to me too, privately, if you want.

 

[Buck 5,000+ posts]

View attachment 31817

This looks correct. Iirc most bridging that I’ve seen happens in the two outside speaker outputs, where you leave the middle two disconnected.

You can usually overpower door speakers, depending how you your high pass is setup, because music is so in and out. The full power is rarely used, but be careful with how much bass or midbass you run, at least at first. I had my doors crossed over kind of high, because I had 150w components and a very underrated 200w per door. I usually crossed at 80-100 hz, and man, they were so loud. Just be careful, take your time to listen to the power properly. Maybe set your HPF kinda higher and then slowly let it down, over time, and you’ll notice if the speakers are distorting or not sounding right. Adjustable db/octave slopes can really help have some bass lower in the doors, without it overpowering the coil, if you had that option, like 18db/octave or 12/dB octave, if you’re braver lol.

I’ve fried some doors speakers with too low of crossovers haha. They don’t move enough to flow out the heat like a sub does, so just be mindful.

 

[nags 10+ year member]

The manual didn't really say, which is where my confusion came from

https://d717eee9-a1c3-4f8b-9945-045286ff38a9.filesusr.com/ugd/35e752_758aa91f93a2475cad0a102829dddd29.pdf

 

[Buck 5,000+ posts]

It’s right here:

 

[Buck 5,000+ posts]

See the + and - at the bottom? That’s the two terminals you use for bridged at 4 ohms.

 

[nags 10+ year member]

See the + and - at the bottom? That’s the two terminals you use for bridged at 4 ohms.

And that'll get me 250x2?

So take 3/4 out and trash them. Then split the front left and rights from 1/2 between 1/2 and 3/4 and leave everything else as-is?

 

[Buck 5,000+ posts]

And that'll get me 250x2?

So take 3/4 out and trash them. Then split the front left and rights from 1/2 between 1/2 and 3/4 and leave everything else as-is?View attachment 31829View attachment 31830

I need to see all of the RCA names. Your amp might automatically know that it's bridged, and you may not have to move RCA's at all, except maybe unplug the ones you don't need. Above channel 1 it says "2 CH INPUT." If you could take a pic and move that wrapped wire out from in front of the labels of the RCA's (that are above the RCA's females on the amp), that would help.

 

[Buck 5,000+ posts]

@Kickstand may be right about not having to change RCA's. Just depends on the amp, but it's looking like that may be the case.

Is there any 2/4 channel switch on the amp that you see?

 

[Buck 5,000+ posts]

@nags

I would clean up that +12v power wire. You don't want stray wires vibrating into your remote wire terminal: