Double check me on my stereo wiring install

[Slide]

Speakers: 4x Polk MM651 (2.7ohm, max 100w RMS)
Speaker Amp: MB Quart NAU460 (4x60w RMS)
Sub: Polk MM1240 (425w RMS)
Sub Amp: Hifonics Brutus BRZ1200.1D (450w RMS)

I've adjusted the gains so that max volume is just under distortion level. I estimate the speakers getting 85w RMS each (low resistance) and the sub getting 425w RMS.

At this point, just the speakers are in and I have not installed the sub. The power setup is 20' of 4awg line for hot and ground that each run to a separate distribution block. The block splits into two outputs that accept 8awg line (the hot block is fused on each line). This is the kit that was used: http://www.onlyinboards.com/AccessoryShop/Products/Electronics/Roswell-Marine-Amp-Wiring-Kit.aspx

So, I have about 2' of 8awg line from the distro block to my speaker amp. This setup is running fine with no issues. My question is, when I add the sub amp, am I going to run into power problems using 8awg line off the block? Is the 20' of 4awg sufficient to power this system, or will the sub need a dedicated hot line?

 

[mark1905]

Re: Double check me on my stereo wiring install

First, nice choice on equipment!

Second.. what do you mean by the Polks getting 85W each with "low resistance"? Are you bridging the MBQuart into 2 channels and then running the speakers at 2 ohms? If so, then you will need a 4 AWG cable JUST for it.

Run a separate 4 AWG cable JUST for the sub amp. 20' is a heck of a long run. Make sure that you're using only tinned, marine power cable. I can't tell from that link if it is or not.

In any case, even if you're running the MB Quart at 4 ohms.. I would run a dedicated 4 AWG line for that HiFonics amp.


Another thing: That HiFonics amp is bad ***.. seriously. It's class D and will do 1 ohm with zero problems. If you're only using it at 4 ohms, you're way under driving it. If you're only going to run one sub, get either a 2 ohm SVC or a 4 ohm DVC sub and run it with a 2 ohm load at least. You've got the capability to run that and more. Might as well use it. Just.. be careful. You can and will fry subs with that amp as I swear it puts out even more power than it rates. I had to switch up to my Pioneer 3500W subs (http://www.amazon.com/Pioneer-TS-W3...2?s=electronics&ie=UTF8&qid=1338304024&sr=1-2) in order for it to handle everything. Speaking of which.. those are the same price as that Polk sub. I would umm.. do a trade in.. if I was you..

 

[Slide]

Re: Double check me on my stereo wiring install

The Polks are low impedance speakers, 2.7ohm apiece. There are 2 speakers in the cuddy and 2 in the cockpit, so each speaker has its own channel; the MB Quart is not bridged.

I was hoping to avoid having to run another power lead but if that 4awg run won't support both amps, guess that's what I'll have to do!

Also - that sub is awesome, I may just have to make the switch!

 

[mark1905]

Re: Double check me on my stereo wiring install

Ah.... you're right. I had forgotten about the 2.7 ohm Polks. Yeah.. you'll want 4AWG for that MB Quart for sure.


FYI.. I had that BRZ12000 amp before I added another sub and switched to the BRZ1700.. and I couldn't find any speaker that would handle the power. Even the 600W HiFonics Brutus sub itself only lasted an hour with the Skrillex before there was literally smoke coming out of it and the voice coils melted..

My 2 x Pioneers now are running @ 2 ohms each for a total mono load of 1 ohm at the amp.. and it barely breaks a sweat. These amps are amazing.. and for the price.. wow.