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HK add-a-sub

1K views 2 replies 3 participants last post by  jag 
#1 ·
hi all,

I was a former M135i owner but thought I share here what I did with my G30 5 series and added a amp and stealth box to a HK set up. Definitely adds the low end bass.

As Harmon Kardon output up to c32Volts peak, you need a LC2I to covert the high level input to a low level signal into an aftermarket amp. Most of the aftermarket amps only go up to c20Vs. This is where the LC2i comes in (made by Audio Control). i.e. it can accept up to 40V

I actually purchased an Audio Control Amp instead (effectively has a LC2i built in). This saves space and cabling etc. Most of their amps accept high level inputs (up to 40v). The audio control amp also has a function called Acubass. It essentially restores the bass as the volume turns up. WHat i understand from factory set up, is that the bass rolls off as you turn up the volume to protect the speakers. You don't want this with a boot sub, hence the acubass function.

Equipment:
10inch Visual Ice Stealth Box ( I know they do one for a F20/F21)
JL Audio W3 Sub 10 inch
Technic PnP Harness (no wiring cut, plug and play) T Harness allows to connect an additional trunk sub and/or power underseat woofers
Stinger 4AWG OFC cable
Audio Control 4 channel amp (bridged 2 channels for the boot sub and other two channels for the underseats)
Low Passed the boot sub and high passed the underseats. It means the underseats don't play any frequency below c60hz.

The amp is all hidden next to the Harmon Kardon amp. I then got Crown Customs to help me a fit an amp board so i can secure the amp and all hidden by trim. Great service from them and attention to detail is brilliant. highly recommended.

Hope this may help someone who is thinking of adding a sub to their HK set up. This set up is fully reversible with no wiring cut and keeps the HK amp in place.

Just in case anyone is interested, I actually have a Audio Control Mono Amp to sell (300 Watts RMS at 2 ohm) and it can accept the high level input from the HK AMP. Its the below and new in box. I will sell at discount as I went for the 4 channel instead. I will also chuck in a bass controller which is normally £50 RRP. I will put a "for sale" thread separately. As this amp is quite tiny, you probably won't need a Amp board made up as i know the F20/F21 have a lot of space by battery if i recall correctly.

 

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