MSP Amp improvements.

[Swerny]

Hey guys,
I recently added a Fosgate 12 inch in a sealed box to my system in place of the crappy stock 8 ohm 8 inch.
I am using the stock Kenwood 529 S amp to power it.
A lot more bass, but i find now when i crank the volume, the sub overpowers the rest of the system quite badly.
I have turned the bass down on the head unit, but have come to the realization that i need MORE POWER!
Now, Option #1: I can pick up another 529 S to run either the 2 front doors, or all 4 doors. Running all 4 doors would have the amp running at 2 ohm stereo which it is capable of doing.
Option #2: I am picking up an MTX Thunder 302 amp., which i want to use to run just the 12 inch sub. I would then move the 529 S to the front doors or all 4 doors.
I would prefer option #2, but am worried again that the sub might drown out the fronts.
Opinions are welcomed on setup and whether to run all 4 doors off the 529 S or just the fronts, with the head unit powering the rears.
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P.S. The reason those are my amp options is that i am buying them used and have deals in the works for both.

Here are the specs on the amps:

Kenwood 529 S: KAC529S
A medium power amp such as the 40 watt x 2 channel KAC-529S 2-Channel Power Amplifier is great for running sub-woofers or mid to high frequency drivers. The bridged power output is 120 watts x 1 channel and the maximum power output is specified at 250 watts. The supply is based on MOSFETs and uses two secondary capacitors and a toroidial noise filter. Features include 2-ohm stability, speaker level inputs, speaker relay protection circuitry, and a Quiet Turn-On circuit.
Product Features :
* Ground Isolation Circuit
* Power MOSFET Switching Power Supply
* Stereo, Mono, or Tri-Mode Operation
* Bridged Power Output at 14.4V (1kHz, 0.8% THD): 120 Watts x 1
* Maximum Output Power: 250 Watts
* Power Output at 2 Ohms, at 14.4V (1kHz, 0.8% THD): 60 Watts x 2
* Power Output at 4 Ohms, at 14.4V (20Hz-20kHz, 0.08% THD): 40 Watts x 2
* 2-Ohm Stable
* 2 or 1 Channels of Amplification

MTX Thunder 302:
RMS Power measured at 12.5 Volts DC:
75 Watts x 2 into a 4 Ohm load with less than 0.05% Thd+N
150 Watts x 2 into a 2 Ohm load with less than 0.1% Thd+N
300 Watts bridged into a 4 Ohm load with less than 0.1% Thd+N
Dynamic Power (IHF-202 Standard) measured at 14.4 Volts DC
120 Watts x 2 into a 4 Ohm load
212 Watts x 2 into a 2 Ohm load
425 Watts bridged into a 4 Ohm load
Signal to Noise Ratio: 110dB A-Weighted
Damping Factor: >200
Frequency Response: 20Hz-20kHz 0.25dB
Maximum Input: 8Vrms
Thunder EQ: Variable Bass Boost (0-18dB) centered at 40Hz
Crossover: Variable 40Hz to 200Hz, 12dB/octave high pass,
24dB/octave low pass with mono output

Thanks!

 

[Aaron]

how will you power all four doors with the kenwood 2 ch amp?

 

[Swerny]

By putting the front and rear speakers on one channel.
That will make the amp see 2 ohm stereo, which it is capable of doing.
The only downside would be that i would lose the fader, but i don't use it anyway.

 

[Focus]

I had a Kicker 600.1 Amp powering a 12" Soundstream Sub and the original Amp powering the 2 Front Speakers and the two back Speakers on the radio output.

It was OK and adjustable enough like that. Don't forget this was 600 Watts on Bass.

You should be fine with Option #2

 

[1sty]

ONly amp the front spealers. Buy a decent 4 channel amp and bridge it to the front speakers only.

Also, adjusting the bass is the wrong meathod, lower the NF level. That is the sub woofers level only. Bass effects all of the cars speakers. Set the amplifier gain with the NF level to max. Then you can easily back it off to lower the subs volume in relation to the rest of the system.

 

[Swerny]

ONly amp the front spealers. Buy a decent 4 channel amp and bridge it to the front speakers only.

Also, adjusting the bass is the wrong meathod, lower the NF level. That is the sub woofers level only. Bass effects all of the cars speakers. Set the amplifier gain with the NF level to max. Then you can easily back it off to lower the subs volume in relation to the rest of the system.

OK, why buy a 4 channel to run 2 channels?
Why not just get a stronger 2 channel, a lot cheaper no?
I understand what you are saying about the Bass level, i still ahve to fiddle with my setup.
1sty, in my first post, Option #1 or Option #2?
The MTX is the better buy over the 529 S right?
Thanks!

 

[jersey_emt]

OK, why buy a 4 channel to run 2 channels?
Why not just get a stronger 2 channel, a lot cheaper no?
I understand what you are saying about the Bass level, i still ahve to fiddle with my setup.
1sty, in my first post, Option #1 or Option #2?
The MTX is the better buy over the 529 S right?
Thanks!

There's actually 4 channels in the front, there's speakers in the doors, and in the sail panel. So you're basically 'bi-amping' the front.

 

[Swerny]

There's actually 4 channels in the front, there's speakers in the doors, and in the sail panel. So you're basically 'bi-amping' the front.

Right there are the 6x 8's in the door and the tweeters in the sail panel.
There has to be some kind of crossover there for the stereo to be able to power them both. There's no way the head unit is working at 2 ohm's.
A shop told me i could run all 4 doors off the stock 2 channel Kenwood.
Now, powering just the front doors, even though there are 4 speakers (counting 2 tweets) should be no problem.
Right? (shrug)

 

[1sty]

There's actually 4 channels in the front, there's speakers in the doors, and in the sail panel. So you're basically 'bi-amping' the front.

NO, they are only 2 channels in the front. The factory wiring is paralleled off in the doors to the factory mazda tweeter. It is not a seperate channel. Bi AMping is when you use 2 seperate channels of amplification to power a speaker component set's tweeter and midrange seperatly. The MSP has no crossover.

 

[jersey_emt]

NO, they are only 2 channels in the front. The factory wiring is paralleled off in the doors to the factory mazda tweeter. It is not a seperate channel. Bi AMping is when you use 2 seperate channels of amplification to power a speaker component set's tweeter and midrange seperatly. The MSP has no crossover.

Right but I meant -- with a 4-channel amp as was suggested you could wire it as 4 channels to the front speakers.

 

[1sty]

OK, why buy a 4 channel to run 2 channels?
Why not just get a stronger 2 channel, a lot cheaper no?
I understand what you are saying about the Bass level, i still ahve to fiddle with my setup.
1sty, in my first post, Option #1 or Option #2?
The MTX is the better buy over the 529 S right?
Thanks!

No, a 2 channel will only be getting a 4 ohm load so you are basicly getting the minimum out of the amp that it is capable of. If for the same money you bought a 4 channel and bridged it to a 2 channel then you are running 4 channels at 2 ohms and maximizing the amp.

As an example:
A Rockford Fosgate P5002 (2 channel) pumps out 125 watts x 2 @ 4 ohms and sells for $315
A Rockford Fosgate P4004 (4 Channel) is rated to 200 x 2 at @ 4 ohms and is only $270

Over all the P5002 is capable of more power output, but not in this application.

I wouldn't spend money on an MTX. The 529 will do for now. if you must replace it wait till you can aford something better not equal.

 

[1sty]

Right but I meant -- with a 4-channel amp as was suggested you could wire it as 4 channels to the front speakers.

Possibly but you would have to either intercept the factory wiring to power the tweeter ad then still run another wire into the door or run 2 new wires in to the doors as they are both powered from a single factory wire that splits in the door.

Not to mention powering a tweeter equaly to a coaxle (that has its own) is waste of the amplifiers potential as the amp will only be giving 1/4 of what it should be to the coaxle to give another 1/4 to the tweeter and the other half is not supplied as each channel sees a 4 ohm load.

 

[1sty]

Right there are the 6x 8's in the door and the tweeters in the sail panel.
There has to be some kind of crossover there for the stereo to be able to power them both. There's no way the head unit is working at 2 ohm's.
A shop told me i could run all 4 doors off the stock 2 channel Kenwood.
Now, powering just the front doors, even though there are 4 speakers (counting 2 tweets) should be no problem.
Right? (shrug)

There is simply a capacitor on the tweeter if memory serves. Its a 2 ohm load just not the same as if you had 2 full range speakers on the same amp channels.

You can run all 4 speakers that way but then the front and the rears play at the same level no matter what. Your fader will be useless. Also to compete with the subs you really need all that power up front. I really hate double up front and rear speakers on a single amp channel, it rarely ends up sounding good.

 

[Swerny]

Thanks for the info guys.
I know there are better amps than what i am considering.
However, budget talks, and i just picked up the MTX for $75 CDN.
It's got more balls than the stock Kenwood for sure, and should push my Punch Stage 1 12 nicely.
I have yet to decide the setup for the 529 S in the front, but will probably just have it power the front doors.
Now, wiring.
I plan to run a 4 gauge power and ground, with an inline fuse and a distribution block in the rear.
I know to avoid running the power wire near the speaker wire, so i was thinking of running the power up the middle of my car. I did this on my Integra.
That way, i can run the RCA's and the speaker wire down each side.
What's everyone elso doing?

 

[1sty]

Thanks for the info guys.
I know there are better amps than what i am considering.
However, budget talks, and i just picked up the MTX for $75 CDN.
It's got more balls than the stock Kenwood for sure, and should push my Punch Stage 1 12 nicely.
I have yet to decide the setup for the 529 S in the front, but will probably just have it power the front doors.
Now, wiring.
I plan to run a 4 gauge power and ground, with an inline fuse and a distribution block in the rear.
I know to avoid running the power wire near the speaker wire, so i was thinking of running the power up the middle of my car. I did this on my Integra.
That way, i can run the RCA's and the speaker wire down each side.
What's everyone elso doing?

The problem in your idea is that the system is already too bass heavy. Adding a more powerful sub amp will only make that worse. Keep in mind that you need to double your power to gain even 3db. And that only if the sub has the ability to move that much more. The stage 1 is only rated for 150 watts rms as it is so bumping it up to over 300 is just applying power that the sub won't really be able to take advantage of. Although the added head room should make the SQ increase although not the SPL.

If you already have the amp then I'd try the MTX on the fronts and see how that does. Since it doesn't take long so might aswell try it each way.

You've got your wiring info kinda of mixed up. You can actualy run power and speaker wire closeand even with each other without much of an issue. However it the RCA's that need to be kept away from the power. I tend to keep everything away from power though and run RCA's and speakers with each other and run the remote wire and power together on the otherside of the car.

 

[Swerny]

Cool. Thanks for the info.
I will play around with it and see what works best.
As for the Stage 1, would I have been better off with the Stage 2?
I bought the sub 2 weeks ago, thinking i would only run it off the stock amp. The sales guy actually talked me out of getting the Stage 2 at the time because i didn't have enough power to run it.

 

[Swerny]

Swapped the Stage 1 for a Kenwood 12 and it's a lot tighter.
Thunder 302 powering it, stock amp pusjhing the front doors = big improvement!