Diabolis

That looks like a great setup and a clean install. I have never used a modern DSP aftermarket processor (I also used to play with this stuff in the pre-DSP days) but the OEM HK DSP system does take the imaging and sound stage to another level. It's amazing what a little bit of out-of-phase audio information will do to our brains.

Re overheating amps - all other things being equal, a class D switching amp is about 80% efficient whereas a class AB would be somewhere in the 65% range, so I highly doubt that this fact alone would solve the problem. IMHO in your case the largest contributing factor by far is the enclosed space where both amps and DSP processor sit; furthermore, IIRC you mentioned something about a 2 ohm sub and whether the amp is stable driving such a low impedance. The lower the load impedance, the higher the output current and thus heat generated by the output devices in the amps.

I would look at somehow increasing the airflow over the amps, probably with a couple of 12V 3" computer fans and some strategically cut holes in the bottom of the trunk liner if that's an option. I'd cut a couple of 3" holes on each side of the trunk liner, mount the fans on the underside on two of the holes (same side of the car, set to blow outward, i.e. extract air from the enclosed space and forcing air from the holes on the other side to pass over the amp heat sinks) and have them turn on with a small driver circuit and relay when the amps are powered on; furthermore, you can reduce the fan voltage somewhat and still get 70-80% of the airflow with only about 20% of the noise they make at full chat.

Two, you might want to try using a 4 ohm subwoofer driver to test if that makes a difference (you could still get the same power but as a result of higher voltage instead of current, which is usually the culprit when it comes to heat).

Lastly, you might want to consider a class D amp for the sub only, where the output device switching is so far out of the audible range that it really isn't going to make any difference to the sound.

Good luck and let us know hoy you make out!

changster

Diabolis,

Thanks for your thorough reply. I took yours & other's advice and replaced my sub amp (Zapco z 150.2) with a mono class D amp (Zapco Z-1KD) which is rated to be stable at 2ohms for 560 watts. They also moved my sub amp from the wheel well into where the old HK sub used to sit on the left side of the panel in the trunk. Here are some pics:





And finally the finished product with the single JL 13TW5v2 "Truck Powerwedge" in the back.



It's only been 1 day but so far no shut downs from the amps at all playing loud music for 1 hour straight. The sounds is fantastic versus the OEM. Great soundstage makes a massive difference (but the OEM HK is good too). Imaging is quite good too with the center more defined. Honestly I think it's all in the tuning, and without a good tuner who knows what he's doing you don't want to mess with the front end. All my stuff is pretty much mid-fi and nothing too crazy, but the tuning makes the biggest difference.

The sub I would say is very balanced vs what the front end is like. Nothing too jarring, but I'm judging from my high school days with 2 12's in the back bumpin 2Pac.

I think the system could use more midbass to add that extra tight punch to drums, but honestly at this point I'm done and going to enjoy it. The C63 pre-facelift is a 6.5" front so to add more midbass will be a big chore and not worth it. I'm not going to start doing the crazy panel cutting and custom work needed for that. The system now as it stands is just 2 tweeters, 2 6.5" midrange, and a 12" sub all run actively through the DSP, then amplified.
The original speakers in the rear doors are left untouched and powered by the exisiting head unit.

changster

One reference for any of you guys doing something like this, is that the electrical system when you turn on the ignition sucks a lot of current. The system voltage drops to around 7V and under the working parameter of the DSP.

What happened then was DSP would turn off, then turn back on when the voltage stabilizes after the car is running. But the amps never shut off, so as the DSP turned back on it would create a big POP sound through the speakers which is not good at all. We had to use a Brax capacitor (1 or 2 farads I forget) to stabilize the voltage upon ignition so the DSP never shut off. Problem solved.

AMG893

Great setup!!! Well Done. Enjoy!!!

Phorte

Looks great!

On a side note: in the Estate, how much room is there where the original HK sub used to sit? I'm looking at putting in a sub+processor+amp but leaving the rest of the HK system untouched and I'd ultimately like to retain my entire Estate boot space.

Is there enough room in the existing sub hole to put something shallow/small in there at all?

changster

Thank you for the compliment.

I can tell you there is absolutely no way you will fit any sub in the left side of that panel. Originally the OEM has a 6.5" subwoofer in there. The shape of the area is also quite weird so unless you do some crazy custom fiberglass enclosure the chances are extremely slim you can fit a sub in there.

You can try a sub in the spare tire well, and maybe the amp and the process there. It would take quite a bit of custom work too though.

Autosport7

What doe s a set up like this weigh? This has always been the major deterrent for me. Yours doesn't seem that it would weight much more than 45lbs or so with box, speaker/magnet, amps, etc...?

Diabolis

Nicely done changster - glad it all worked out well in the end!

I solved the car start "speaker thump" by building a circuit that creates a 15-20 second delay on the "power on" signal to the amp(s) from the moment power is applied as the car ignition is never in position "II" for more than a couple of seconds before it gets started. The stiffening cap however is a considerably simpler and thus more elegant approach.

My past experience - but again, this is all based on car audio as it was some 15 years ago - has been that the weakest link in most OEM car audio systems were the actual drivers. I have no idea if that is still the case (the C63 sounds VERY good compared to my old jalopies), but I am entertaining the idea of replacing the OEM drivers with Focal, Seas, Scanspeak or Dynaudio units just to see what difference it would make. Will post an update if I ever get around to it.

As for the extra weight and lost cargo capacity, my preferred setup for my current vehicles is to mount the sub amp either on the subwoofer enclosure itself or mount both the sub and the amp on a base that properly fits the vehicle and prevents them from sliding around. For the amp power I have used connectors from old UPSs where the extended battery pack connects to the inverter unit, which are rated at 80 amps and accept 0 AWG wires. That way the whole setup can be easily removed in seconds (with no tools) when I need the cargo space or am going to a track HPDE event.

changster

I wish I would have weighed everything but I didn't. The sub box is light though at 35 pounds according to JL. The two amps maybe 20 pounds and some misc stuff. Net I would say you added max 40 pounds because the spare tire is removed and that thing is heavy.

changster

You are very right that the C63 OEM HK setup is actually very good for an OEM setup. It is pretty balanced from the factory with a high soundstage. The drivers themselves of course are worse than aftermarket ones. However if you just replace the aftermarket drivers with a component set using passive crossovers I'm not sure whether the crossover settings will blend in well with the factory DSP crossover points. Would be good to know if you ever did it though.

On the removal in seconds thing, what exactly would you be disconnecting? I had thought about mounting the amp(s) on the enclosure or a floor board too but when upon removal it would mean disconnecting all sorts of wires ie speaker cable wires, amp power cable, etc. it would be a big chore wouldn't it? Right one when I want to remove my sub incase I need he boot space is I disconnect the two banana plugs to the speaker and take out the sub. Really easy.

Diabolis

I wouldn't be installing any crossovers - I would use the existing factory DSP crossover points and amplification, and only replace the actual drivers themselves. The factory system already uses "separates" (i.e. midrange and tweeters in the doors, woofers under dash, etc.). I would only attempt to replace the factory tweeters, 4" midranges, 6.5" bass drivers, etc. with better-quality drivers that would use the existing OEM frequency range crossover points and amps to see if it makes an improvement.

The power and ground leads (one large connector), signal input (RCA) and the remote turn-on (bullet-type connector). I also used to just disconnect the subwoofer speaker banana plugs - until I fried a very nice PrecisionPower amp in the Audi when the exposed banana plugs touched while driving and shorted the amp (the amp was active - I had no provisions for turning it off). A little switch or bullet connector on the remote turn-on trigger wire for the amp should do the trick though if you'll only be removing the sub. I agree that for road cars it is by far the easiest solution. On the P-car which periodically ventures on the track, I take out as much weight as I can or anything that could be even remotely loose, so the amp and sub come out together.

pino brabus

hello, the audio signal to the RCA where did you get it?

changster

Right after the factory amplifier.

pino brabus

The way it was done! By chance you have photos or other info, I would not know how to do! First, I apologize for the trouble and I take this opportunity to thank you for the answers!