Tweeter Hissing - Aftermarket System

[Dav3]

Hey all,

I'm currently stuck with an issue of hissing tweeters on an aftermarket system from integral audio

This is the system (Great system)



I've already tried a myriad of troubleshooting by myself and together with the company including:

- Replaced the Amplifier
- Updated the firmware settings on the DSP
- Swapped cables
- Tested grounding resistence
- Untied signal and power cables to avoid interference
- Adjusted Gain Settings (everything on minimum)

All of this, and no solution. Both Tweeters still hiss loudly with the music off (and also with music on).

Can anyone with the same or similar issue suggest any possible solution?

Alternatively can anyone comment if these things might be causing it:

- Coding ASD off and having Physical Bypass on the Amplifier (as in, both things together causing issues?)

- Having AppleCar Play wifi antenna retrofitted but instead of routing the entire cable to the footwell comportament, leaving it underneath the head unit? As in, the wi-fi antenna placement somehow creating interference to the tweeters?

If anyone can help, I'd be very grateful!

[Encanto]

Hiss is caused by a higher than nominal noise floor - the input level of the aftermarket amp is not matched to source output level.

This system is designed for the source to be the OEM amp high leve outputs, which makes it tricky to interface with the aftermarket DSP/amp inputs - OEM amp has dynamic outputs both in output level and in EQ based on speed.

The best solution to this hiss problem is remove the source of the hiss - the OEM amp from this system: either code the OEM HU to output analog (no MOST), or to use a MOST converter as inputs to the aftermarket DSP/amp. The hiss can be better controlled by low level inputs or digital (if the aftermarket DSP/amp can accept optical inputs).

[Dav3]

Originally Posted by Encanto

Hiss is caused by a higher than nominal noise floor - the input level of the aftermarket amp is not matched to source output level.

This system is designed for the source to be the OEM amp high leve outputs, which makes it tricky to interface with the aftermarket DSP/amp inputs - OEM amp has dynamic outputs both in output level and in EQ based on speed.

The best solution to this hiss problem is remove the source of the hiss - the OEM amp from this system: either code the OEM HU to output analog (no MOST), or to use a MOST converter as inputs to the aftermarket DSP/amp. The hiss can be better controlled by low level inputs or digital (if the aftermarket DSP/amp can accept optical inputs).

Thanks for the reply!

On surface level I kinda understand what you mean, but this system is specifically designed for the OEM amp and I believe the hiss is not supposed to be there.

Assuming it shouldnt be there, what else could be the case of it?

[Encanto]

Originally Posted by Dav3

Thanks for the reply!

On surface level I kinda understand what you mean, but this system is specifically designed for the OEM amp and I believe the hiss is not supposed to be there.

Assuming it shouldnt be there, what else could be the case of it?

You have a noisy OEM amp.

[Dav3]

Originally Posted by Encanto

You have a noisy OEM amp.

I removed RCA input (so I'm guessing Harmon Kardonn) and connected the Tweeter straight to the aftermarket amplifier. Hissing sound was still present.

So I'm guessing the aftermarket amplifier has noise floor?

[Encanto]

Originally Posted by Dav3

I removed RCA input (so I'm guessing Harmon Kardonn) and connected the Tweeter straight to the aftermarket amplifier. Hissing sound was still present.

So I'm guessing the aftermarket amplifier has noise floor?

Unplug OEM amp (20-pin connector in photo), check for hiss. That will telll you where the hiss is coming from - OEM amp or aftermarket setup. If you hear hiss after unplugging OEM amp then hiss is from aftermarket setup. Then remove power from aftermarket setup. You should not hear any hiss.

[Budget M3]

Originally Posted by Encanto

You have a noisy OEM amp.

My money is on this ^^. I also have the Integral Audio system and have no such issues.

The Arc Audio amp and DSP do wonders for the sound in an F80, but just as the stock HK speakers are weak, so are the HK amps that IA leverages. The IA system takes its input from the HK system, so if HK is feeding unwanted frequencies, IA will play any unwanted frequencies that they are not expecting.

It may be difficult to find another source to feed the IA system, so you might try a Bluetooth dongle wired directly to the IA system. Try going both direct to the amp and then try it through the DSP.

If neither this nor Encanto's recommendations isolate the source of the problem, I’d try another (known good) HK amp before throwing any more hardware at the problem.

Oh, and the IA system physically bypasses ASD, so there should be no potential for those signals to get passed on anyway.

Just my $.02…hope it is helpful!