As you guys all probably know the stock Nakamichi amp is a 5 channel so when it goes you loose your subwoofer as well. Swapping headunits while great, sounds tinny and has NO bass. So I am looking for some bass, stock levels or a little better is fine with me.

I am using the stock speakers with a Kenwood HU and I am perfectly fine with it except for the bass.

-Can I just add an aftermarket 2channel amp to power the stock Nakamichi sub? That will be my first and most preferred option

-Do I have to get a new sub because of the resistance of the Nakamichi sub? I heard it was 5ohms instead of 4 or 2 so most aftermarket amps will not work with it

 

I have a 1998 Lexus ES 300 with the Nakamichi system and recently blew the amp from trying to power an after market 8 inch sub dual voice coil wired in parallel for 2 ohms. The stock sub is a 2 ohm sub, but the wattage is very low. The stock Nakamichi amp is rated at 33 x 4 max power and 60 x 1 max power for the sub. You might blow the stock sub if you power it with a strong amp. If your going to run an after market amp for the sub, might as well buy an after market sub dual voice coil from Crutchfield.com. The original sub I bought was a Polk Audio 8 inch for like 70 dollars and sounded very bassy for an 8 inch sub. Hope this helps you.

 

Hey Robert you have no idea how helpful your post is, thank you very very much. I do have other ideas/clarifications.
So the Nakamichi is actually a 2ohm/60watts-max/8" sub right? Do you know the RMS for the amp?
I know the stock speakers are rated at 20w RMS/40w-max 4ohm so that fits exactly in line with the built in amp from my Kenwood (probably why it sounds better than stock even without a dedicated amp). As you can see I do not want to shake out the rear windows and frankly I do not even want the bass heard outside the car with the windows up (lol I am getting old). So I will be fine with a cheap 2 channel amp that puts out 40-60watt RMS (I will only be using one channel so I do not overpower the stock sub) E.g. http://www.crutchfield.com/p_070XPA2...l-XPA2500.html

My main hesitation for not getting an aftermarket sub is how easy/difficult it will be to find one that will drop into the stock location without having to grind out/open my rear hole up. I will do an aftermarket sub only if it will drop in stock location without modifications, I just want the system working again is all. Not really looking to upgrade it or increase bass, just have some bass

 

Here is the link of my issues I was having with my amp and sub woofer. https://www.clublexus.com/forums/es3...-es-300-a.html

The stock Nakamichi sub is 2 ohm and 8 inches for the 1998 ES 300 and I would think it would be close to the same for other Lexus models of the same year or close to the same year. Dont know what year and model you have, but it should be close. As far as RMS of the amp, I have no idea, I couldnt find any info on here, just what was on the label of the amp. And as far as swapping the OEM sub with an aftermarket sub, Crutchfield was very helpful in finding one that would work for my car. The only modification I had to do, was to cut part of the metal that was attached to the OEM sub woofer in order for the third brake light / grill to snap back in place. But as far as the hole in the rear deck, no modification needed, the JL 8 inch sub I ended up using instead of the Polk Audio fit perfectly with no problems. Its bassy, but not window shattering or vibrating enough to give you a massage. I also installed Dynamat on the underside of the rear deck to make the bass sound cleaner inside the car.

 

Ok just a heads up, the Nakamichi subwoofer for the 1999 SC400 is actually a 5-ohm 10" sub. I will take the amp apart again soon and see if I can get the power being sent to the sub.

 

So I picked up a $50 Dual 2-channel amp from Walmart (of all places), bought an amp install kit off ebay for less than $20 and wired up the stock Sub that way. I only used one channel of the amp and to be honest that thing thumps waaaay more than I will like lol. Yeah I turned it down and now my car sounds INCREDIBLE, better than the stock Nakamichi setup by far and better than my mum's 2009 RX350 (with Mark Levinson or whatever the upgraded stereo is, can't remember), better than my IS300 etc etc.

Setup is
-Kenwood Sirius ready HU with variable color display (on bright white)
-Replaced 2 rear speakers with drop in 4" Infinitys
-Dual 2-ch amp powering the sub
-Kenwood Sirius tuner plug in to have Sirius on my headunit
-AC control unit lights replaced with white LED

 

Hi,

Just to clarify you're using the 2 channel amp to power all four speakers and the sub-woofer? Did you use the existing factory wiring or did you have to run additional cables?

I have never really understood why even a cheap aftermarket sub amp wants a huge power cable while the factory amp has reasonable sound with small gauge power cables...

 

No. He is using 1 channel of his 2 channel amp to run the sub. Yes, he had to run a power cable to the battery.

Limitations of power. If you only need 50 watts, that's about 5 amps (assuming 80% efficiency) and a piece of 16 gauge can feed that. If you do 150 watts, that's only about 14 amps, but you need to step up a bit in wire size. Given that most aftermarket amps will have a circuit that delivers more power based on the input (versus just giving distortion), you can end up with a 200 watt amp delivering 400 watts. Don't want to try and pull 40A through a piece of 14 gauge wire.

Big Mack

 

What Big Mack said