Is It Just My Harman Kardon System Thats Hopeless ?

[eurorover]

The HK system is a pile of over priced pants. The Oe amp and speakers cant handle anything. I ended up changing all my speakers and amps and now it is a lot better.

You got a plasic box with 2 x 5" speakers for bass it is just going to resonate and cause vibrations. I had to pack the top of mine just to lower the vibrations

[T16]

Guys,

I recently tested a BM24 radio, thought it was AMAZING compared to the standard pap..... THEN I closed the boot, and the RUBBISH sound quality returned, just the same as before.

So with the boot open, the bass was AMAZING, and the sound was deep, and lush, but with the boot closed, the sound/bass was GARBAGE.

Is it possible that the HK sub can be wired out of phase? I see that the speakers can only be wired in one way, but what about a) the connector to the sub, and b) the connector into the HK amp itself?

Its SO SO SO BAD, that its like its out of phase, Im not joking!! its like a BASS VACUUM in the car, boot open, its absolutely wonderful, deep, musical, luscious.

Anyone with a RUBBISH HK sub, open the boot and listen to the music inside the car, you'll be amazed, its like a new stereo system.

The only question is why/how it can possibly be better with the boot open?

[Geoff130]

Originally Posted by dissy1810

I have the harmon kardon speakers in my car powered by an aftermarket kenwood stereo and a fusion amp to power the sub all of the door speakers were great but the boot sub speakers were poor and couldn't handle bass so I replaced them with these and the sound is great now Attachment 15069

I tried this but the problem is that the parcel shelf sub is trying to direct sound from that centrally located port to the front of the car and it loses power by the time it gets there. The amp or sound processor as it's sometimes called doesn't help, it really is tuned for different vehicles, tourers or saloon then both different again for highline. What is actually in the box are six amplifiers driven by active crossover filters that drive the sub to distortion on high volume levels and kill the bass to the doors so even if you replace the speakers they still lack low end response. Use a BM54 radio tuner and change the correct eight capacitors (£2.00) and your HK system is a completely different animal.
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[Canonite]

Originally Posted by Geoff130

I tried this but the problem is that the parcel shelf sub is trying to direct sound from that centrally located port to the front of the car and it loses power by the time it gets there. The amp or sound processor as it's sometimes called doesn't help, it really is tuned for different vehicles, tourers or saloon then both different again for highline. What is actually in the box are six amplifiers driven by active crossover filters that drive the sub to distortion on high volume levels and kill the bass to the doors so even if you replace the speakers they still lack low end response. Use a BM54 radio tuner and change the correct eight capacitors (£2.00) and your HK system is a completely different animal.
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Perhaps a guide of a couple of diagrams to show what needs replacing, what to replace it with and where to get it

[Geoff130]

Above is the circuit diagram of the filters that drive the door amplifiers. They each form a second order high pass Butterworth filter which means that they have a flat response above the cut-off frequency but below that the signal starts to be rapidly attenuated. The four 120nF capacitors mainly determine this frequency for the front doors and the four 82nF capacitors set the rear door frequency. To be honest I didn't do the maths but used a hunch and fitted four 470nF capacitors in place of the 120s, blue rectangles in the second picture. For the rear doors I replaced the 82nF's with 330nF's(orange in the second picture.

If anyone's interested I'll post more details, all the parts where about £1.00 in total from RS Components, although you may have to buy in packs of ten. Maplins may also supply suitable parts.

The circuit siagram is as shown in the top picture of the previous pictures the bottom one shows it after modification.

[T16]

Anyone care to comment on why it sounds so amazing with the boot open?

Has anyone actually tested changing the phase of the sub to see if it improves things with the accoustics of the car?

Im tempted to disconnect the sub completely, it seems to manage to sound even worse than the base Kenwood setup in a diesel ZT.

[Geoff130]

I've tried it all ways, reversed the left speaker only, right speaker only and reversed both. Nothing seems help most make it worse.
My thoughts on the better sound with the boot open is that you are hearing the sound from the rear of the drivers rather than modifying the output from the port in the parcel shelf. Try it with the boot open and all doors & windows shut.

[Alikris]

I fitted an HK sub enclosure, replacing the drivers with Rainbow EL-W5 woofers and Bass Face Class D Amp. Sounds wonderful. One will never achieve 'boy racer' type thumping though. I've set the crossover at around 80Hz

I do agree that there's more bass in the boot than in the passenger cabin. When I want extra bass I open the ski hatch a little. As has been said, the main problem is the tiny speaker vent in the rear parcel shelf, it's just too small and it's constricting the bass output. Personally I think the HK enclosure is over-engineered and useless, as well as reducing boot space. It would have been much better if they'd mounted the bass drivers directly to a plywood rear parcel shelf.

I did try reversing the phase, made no improvement to the sound.

IMO if you want better sound you need to replace the door speaker drivers with some quality aftermarket ones. I fitted Rainbow components to my front doors last week, driven from the Kenwood head unit I fitted. Sound quality is superb compared to before. I'll fit Rainbow rear door speakers later on this year sometime.

Ali.

[victorgte]

So happy I found this thread regarding the HK system. Mine too sounds terrible compared with many other systems I have used. I'm not technically minded one ICE products but I am willing to go with and buy the necessary bits to modify/improve it. Often used as a selling point to entice buyers but a disapointment to listen to.
My Kenwood DD unit bought last year in my other 75 sounds miles better. Cant wait to get home and open my boot!

[SD1too]

Originally Posted by nickpscott

The problem I find is my system cant handle any kind of Bass whatsoever, I cant turn it up into the + range on the headunit and has to stay at 0 or go into a minus figure to stop any distortion ..

You are quite right Nick. The problem is very simple and it's down to design.

The HK amplifier input is fed from the loudspeaker outputs of the radio module. As any radio engineer will know this is extremely bad practice since the distortion created by the radio power amplifier will be exacerbated by the HK amplifier. What HK should have done is to take their input from the pre-amp of the radio module.

Simon