I know there's been a lot of discussion over the years about the dreadful sound out of the HK sub. Many have spent $$$ in DSP adapters, extra amps, and premium subs. I priced out a JL Stealthbox and amp and thought, "wow, this is more than my first two cars combined." So I started looking at how I could fix the HK sub (not the Alpine as the extra voice coils add another wrinkle) using the factory amp for easier spending money. Well below is my list in order of preference:
1. Upgrade the subwoofer to a $100 Pioneer sub with a modest box, two resistors, and a low-pass filter to kill the non-sub frequencies RAM sends to the sub. For $400 total and you get a system with really good bass, with no punchy boominess that the HK delivered. Read the full details here as I figured it all out. I'm running this now with the bass EQ set on 0.
1. Tied for first place. Upgrade your factory 6x9s to CDT Audio CL69S. I got them on sale from CDT for $220 plus $10 for the Metra 72-6515 adapters (need these to keep ANC happy). Now unplug your sub and don't look back. The factory amp can drive the CDTs very well and you will be astounded at what you've been missing. I ran this with the bass EQ on +3.
3. Simply unplug your factory sub and turn up the bass - free.
Why did I list two #1's as a tie? Well I already had the CDT's installed and dang they sounded good without the factory sub. They rock hard and if you are looking for the lowest cost fix, that's it. My problem was that I knew I no longer had a sub and was missing those ~40Hz sounds at the low end. So full disclosure, I'm in for $630 plus whatever the Infinity dash speakers ran way back when but it sounds quite good.
One last data point for those who want to roll their own. The HK sub is 5.2 ohms so you do not want to be using a 4 ohm aftermarket speaker with the factory amp, BUT if you use the low-pass filter it bumps it up to 6.2 ohms. This means with it you can use any 4 ohm woofer with the factory amp, plus it will cut any frequencies above 78Hz.
1. Upgrade the subwoofer to a $100 Pioneer sub with a modest box, two resistors, and a low-pass filter to kill the non-sub frequencies RAM sends to the sub. For $400 total and you get a system with really good bass, with no punchy boominess that the HK delivered. Read the full details here as I figured it all out. I'm running this now with the bass EQ set on 0.
1. Tied for first place. Upgrade your factory 6x9s to CDT Audio CL69S. I got them on sale from CDT for $220 plus $10 for the Metra 72-6515 adapters (need these to keep ANC happy). Now unplug your sub and don't look back. The factory amp can drive the CDTs very well and you will be astounded at what you've been missing. I ran this with the bass EQ on +3.
3. Simply unplug your factory sub and turn up the bass - free.
Why did I list two #1's as a tie? Well I already had the CDT's installed and dang they sounded good without the factory sub. They rock hard and if you are looking for the lowest cost fix, that's it. My problem was that I knew I no longer had a sub and was missing those ~40Hz sounds at the low end. So full disclosure, I'm in for $630 plus whatever the Infinity dash speakers ran way back when but it sounds quite good.
One last data point for those who want to roll their own. The HK sub is 5.2 ohms so you do not want to be using a 4 ohm aftermarket speaker with the factory amp, BUT if you use the low-pass filter it bumps it up to 6.2 ohms. This means with it you can use any 4 ohm woofer with the factory amp, plus it will cut any frequencies above 78Hz.
