4 channel amp suggestions for 8" sub and Polk MMC6500 Components

youthman

Currently, I'm using an MTX Thunder 240 (200w bridged x 2) with a JL Audio 8w0 SVC sub (75w rms, 150 peak). I have installed Polk db571 5x7 Coax in the front doors and factory 5x7 in the rear doors.

I want to move the Polk db571's to the back doors and install a pair of Polk MMC6500 Components in the front doors or in kick panels.

My thought is to sell the MTX and buy a 4 or 5 channel amp. I would bridge 2 channels for the sub and use the other two channels to power the components.

I have a few questions:

1. All the speakers are 4ohm. The sub in bridge mono would yield a 4 ohm load. When I hook up the components to the two channels (one component for each channel), since there are two 4ohm speakers (woofer and tweeter), does the amp see those as a 2ohm load or still a 4 ohm load?

2. Any budget amps less than $100 that you would recommend? I don't mind used, even using "old school" amps.

Some amps I have looked at locally are:

Kicker KX 700.5 (5 channel amp) (40x4 @ 4ohm, 70x4 @ 2ohm, 150x2 @ 8ohm) - $80

Soundstream Rubicon RUB4.500 (75x4 @ 4ohm, 125x4 @ 2ohm, 250x2 bridged mono) - $80

Eclipse AE4000 (75x4 @ 4ohm, no specs for 2ohm, 150w bridged mono)
- $100 firm

Kicker ZX350.4 (60x4 @ 4ohm, 90x4 @ 2ohm, 175x2 bridged mono) - $80 - $100

Would you recommend any of these and why?

I am leaning towards the Kicker KX 700.5. I'm thinking I could bridge two channels to power the left door component speakers, bridge two channels to power the right door component speakers and bridge the sub channels to drive the sub.

youthman

I have another question. When you hook up the components, does the amp see a 4ohm load or a 2ohm load since there are two speakers? My guess is somehow 4ohm...just don't know why.

motomonkey

1. 4 ohm
2. the Kicker 700.5 at $80 should work out fine for you. These amps produce more than the stated power. Much higher quality than the SS.
The amp will see a 4 ohm load as you will run the power through the crossover.

youthman

Thx Moto. I have been out of car audio since I was a teenager 16 years ago. The old school Kicker, JL, SoundStream and Fosgate were rock solid amps. Wasn't sure if they were still producing good amps nowadays. I was supposed to meet up with the guy today but wasn't able to. Maybe tomorrow after paintball we can hook up. Thx again.

youthman

If I get the Kicker ZX700.5, I notice the specs say 40x4 @ 4ohms and 75x4 @ 2ohms. Can I hook all four of my door speakers to the amp and get the full 75 watts per speaker?

If so, wouldn't I need to hook both component speakers up to one channel so that the amp sees a 2ohm load for that channel and then hook the other two 5x7 speakers to another channel so it sees them @ 2 ohms too? Then that would leave 2 extra channels but I'm guessing you can't use them...or can you? I've never had more than a 2ch amp going to subs so having one amp to power everything...I still have a lot to learn.

youthman

I looked at the manual.

Stereo Operation with Subwoofer
KX amplifiers are capable of operating into a minimum impedance of 2 ohms
per channel in stereo operation and 2 Ohm mono on the subwoofer channel.

All Channels Bridged
The KX700.5 is capable of bridged operation on AMP 1 and AMP 2. This, for
example, would allow you to bridge AMP 1 to run the Right side and AMP 2 to
run the Left side. But remember AMP 1 and AMP 2 are only stable down to 4
ohm mono.

So if I hook up the 4 door speakers, one to each channel, I'm only getting a 4 ohm load which is 40x4. I could bridge the two channels but would only be able to hook them to my two component speakers since it's only stable in bridge at 4 ohm. I could then use the HU to power the back door speakers.

Doesn't look like there is a way to power all four door speakers and get a full 75x4 to them unless they were each 2 ohm speakers and they are not.

Am I understanding that correctly?

youthman

I purchased the Kicker amp the other day. I'm trying to decide whether to bridge two channels and send that to each component so they have maximum power going to them and power the rear 5x7 door speakers with the HU. That's what I'm leaning towards instead of doing 70x4 to the four door speakers.

Vital

Get rid of rear speakers alltogether, if you want sound quality.
If you insist on having speakers in the rear for whatever reasons - run them off the headunit while fronts are amped/bridged.

BTW - compare both options - with and without rear speakers, you might be surprised to see what you find sounding better

youthman

I guess I never really even thought about not having rear speakers since i have a family of 6 and figured the passengers would like to have good sound as well.

My original goal was to improve the factory system by adding an aftermarket HU, replace the factory sub but use the existing sub enclosure and replace the door speakers.

I started out buying a Kenwood KDC-571 HU (something close to that), Polk MMC6500 Component Speakers and an MTX Thunder 240 amp on Craigslist for $140. I then bought a JL 8W0 for $40 to replace the factory sub. As you can see, I'm looking for a very budget friendly system.

I installed the HU, put the 5x7's in the front doors, left the factory 5x7's in the back doors and powered those 4 speakers with the HU and hooked my 2ch amp bridged mono to the JL sub.

Now that I have purchased the Kicker 700.5 amp, I'll be selling the MTX amp, moving the db571 5x7's to the rear doors and installing the Polk components in the front.

I'm also looking to upgrade the JL sub to maybe an 8W3 so I can take advantage of the more powerful Kicker amp.

Vital

Just try out different options man, see what you like better.
Here's another option for you:

Bi-amp those mmc6500s instead of bridging. IMO MMC's tweeters are too bright so this option will let you turn them down (or up) as much as you want in comparison to the woofer so u'll get a PERFECT tweeter/woofer ration. And btw these speakers have GREAT midbass which once again can only be achievable with bi-amp'ing.

I have these same exact speakers bi-amped and haven't looked back. In your case with 6 people in the car (minivan??) you might wanna have some rearfill for them but as i said - try each of the options for a week or two, see what's your me/family perfect ration is.

youthman

Thx Vital. If I bi-amp the components, would I still use the component xover and set it to dual or just use the xover in the Kicker amp and bypass the Polk xover altogether?

I'm installing it in an 02 Ford Expedition

youthman

There are two JL 10W7's local for $200. Maybe I should jump on these and sell one of them.

Vital

youthman wrote: »

Thx Vital. If I bi-amp the components, would I still use the component xover and set it to dual or just use the xover in the Kicker amp and bypass the Polk xover altogether?

I'm installing it in an 02 Ford Expedition

bi-amping means u're still using component's passive crossovers and yes, just "set it to dual imput"

Vital

youthman wrote: »

There are two JL 10W7's local for $200. Maybe I should jump on these and sell one of them.

Or use both of them LOL

youthman

Haha. True. Just don't want to sacrifice that much space.

The guy I bought the amp from said I could even bypass the passive xovers for the components and use the xovers in the amp.

Thx for the suggestions.

Vital

I'm sorry but no you can not. Amp's x-over is in different rfequency range then speaker's x-over.

youthman

I gotcha. I was planning on using the Polk xovers anyways since they were designed specifically for those speakers.

Still trying to find a JL 10w3v3 sub. I'm hoping to install the amp and speakers this weekend.