[TheBlondeFella]

Hi all.
I've just had a new amp fitted to power the front doors speakers and under seat subs. Now though my front parking sensor tone and general warning sounds are so loud it's ridiculous. Turning them down to the minimum makes absolutely no difference.
Anyone out there also experienced this issue and if so did you overcome it? Cheers. Steve

[cdgatti]

your amp gain is too high

[bmw325i]

Originally Posted by cdgatti

your amp gain is too high

This

[TheBlondeFella]

What happens if turning the gain down doesn't make any difference?

[afsar]

I think it could be due to your amp only accepting rca input and you have fed it high level input. Had this issue with alpine pdx once and while rest of levels can be adjusted PDC and other gongs remained quite loud annoying.

Solution: Use a high quality loc converter or change you amp. Coding your HU to hifi is also one option but I don't know what you are using so can't say it is applicable or not.

[Technic]

Originally Posted by TheBlondeFella

What happens if turning the gain down doesn't make any difference?

It helps if you list all the equipment installed. We are trying to read minds, but that will take a couple of generations...

[Stream]

It's so weird that this problem still didn't solved. Every time people ask, they got different answers and I don't remember anybody who reported about success.

I noticed that with Base Stereo system (Professional CD + 6 speakers, no tweeters, no amp) PDC sound DOESN'T changes it's volume when you turn volume up\down. So, I guess:
1. There are two output signals - audio + PDC. i.e. constant 2v for PDC and variable 0.1 - 9V for audio.
2. Two signals summing before going out from headunit.

Then, we can have E90 with Professional Audio, Front and rear PDC and three situations.
1. We add LOC, external amp with line level input and doesn't recode HU to Hi-Fi. We try to make output more loud and i.e. adding 2x gain level.
Then we got:
* LOC convert audio signal from 0.1 - 9V to i.e. 0.1 - 2V and PDC\gong from 2V to 0.6V.
* Amp makes makes output level >0.1 - 9V and more than 2V on PDC.
* Here we notice our gong level grew louder.
* But we got better audio quality, higher undistorted level.

2. We add external amp with high level input and doesn't recode HU to Hi-Fi. We try to make output more loud and i.e. adding 2x gain level.
Then we got:
* Amp makes makes output level >0.1 - 9V and more than 2V on PDC (remember we wanted more output, 2x gain).
* Here we notice our gong level grew louder.
* But we got better audio quality, higher undistorted level.

3. We add external amp with line level input and recode HU to Hi-Fi. We try to make output more loud and i.e. adding 2x gain level.
Then we got:
* 0.1 - ~4V line level audio output and ??? PDC output (2V or maybe line level, ~ 1V)
* Amp makes makes output level >0.1 - 9V and more than 2V on PDC. Same story.

Here i have only one solution:
Adjust level gain so amp outputs the save voltage as HU internal amp (9V). Then PDC\Gong volume will be ok.

So I have thee questions:
1. My guess about summing, is it true ?
2. PDC level. If it's level changes with recode to Hi-Fi or not?
3. Maybe someone have better solution?

[TheBlondeFella]

Originally Posted by Technic

It helps if you list all the equipment installed. We are trying to read minds, but that will take a couple of generations...

Sorry ...

i) Professional HU. (not coded anymore ... was coded to hifi and then back to stock)
ii) Gladen M-LINE 75.4 – 4 Channel Full Mosfet Amplifier
iii) Gladen 201 speaker set

Hope this helps a little better.
The warning gongs have now been coded so that they don't come through the HU so they are now a lot quieter. Its just the PDC (front and rear) that i need to sort!

[Technic]

Originally Posted by TheBlondeFella

Sorry ...

i) Professional HU. (not coded anymore ... was coded to hifi and then back to stock)
ii) Gladen M-LINE 75.4 – 4 Channel Full Mosfet Amplifier
iii) Gladen 201 speaker set

Hope this helps a little better.
The warning gongs have now been coded so that they don't come through the HU so they are now a lot quieter. Its just the PDC (front and rear) that i need to sort!

Coding to HiFi should have taken care of this PDC beeps level issue. My system is HiFi with aftermarket amps and a H800 DSP and the PDC beeps level is "normal" (to me) -and adjustable via iDrive. I have it set to minimum.

You should be able to adjust the PDC beeps level via the OEM HU.

That Gladen amp accept high level inputs but the minimum gain is pretty much what you must use as the OEM HU outputs are 7.5V max. I would add a LOC so the OEM HU output level can be lowered to 2-3Vmax, then you will be able to adjust the amp gain to your taste.

[Technic]

Originally Posted by Stream

So I have thee questions:
1. My guess about summing, is it true ?
2. PDC level. If it's level changes with recode to Hi-Fi or not?
3. Maybe someone have better solution?

HiFi will take a ~7.5V high level peak output to a 4V low level (within a 5V balanced signal) peak output. So yes, PDC level will be lower in a coded-to-HiFi Stereo OEM HU.

But as stated above, the trick is actually having headroom at the aftermarket amp gain scheme. If the PDC level is already close to the minimum gain then it will be loud because you cannot lower the gain anymore. Either a good LOC or a processor can take care of this.

[TheBlondeFella]

Originally Posted by Technic

Coding to HiFi should have taken care of this PDC beeps level issue. My system is HiFi with aftermarket amps and a H800 DSP and the PDC beeps level is "normal" (to me) -and adjustable via iDrive. I have it set to minimum.

You should be able to adjust the PDC beeps level via the OEM HU.

That Gladen amp accept high level inputs but the minimum gain is pretty much what you must use as the OEM HU outputs are 7.5V max. I would add a LOC so the OEM HU output level can be lowered to 2-3Vmax, then you will be able to adjust the amp gain to your taste.

Thanks for your input. My head unit does allow volume adjustment of both PDC and Gongs but neither of the adjustments are making any difference at the moment. I do know that the GONG has been removed from the HU via coding as it was the only way 'the fitter' could make it go quieter. A lot of this is going over my head though ... What's a LOC?

[Technic]

Originally Posted by TheBlondeFella

Thanks for your input. My head unit does allow volume adjustment of both PDC and Gongs but neither of the adjustments are making any difference at the moment. I do know that the GONG has been removed from the HU via coding as it was the only way 'the fitter' could make it go quieter. A lot of this is going over my head though ... What's a LOC?

Line Output Converter

[TheBlondeFella]

Originally Posted by Technic

Line Output Converter

Thanks .... Spoon feed me, what does it do and how will it work in my situation.

[Technic]

Originally Posted by TheBlondeFella

Thanks .... Spoon feed me, what does it do and how will it work in my situation.

http://www.e90post.com/forums/showpo...1&postcount=10

[TheBlondeFella]

Sorry I just want to know if this will definitely fix my issue. I've spent more money on an amp and speakers than I've ever spent in the past, I've then paid a guy what I earn in a day for 3.5 hours trying to set the pre wired and installed system up for what I can see is a flawed outcome. I'm not happy and neither is the wife for spending so much time and cash on what seems like ' flogging a dead horse' I just want to know if anything is going to work before I waist cash that I really don't have.

[Stream]

TheBlondFella
You can also use simple DSP, such as "Mini DSP" (~150$) to equalize HU output, I mean read RTA,
Center freq. for PDC and lower level on this freq.

My head unit does allow volume adjustment of both PDC and Gongs but neither of the adjustments are making any difference at the moment.

You have BMW Professional CIC, not just Professional CD Radio right?

[TheBlondeFella]

Originally Posted by Stream

TheBlondFella
You can also use simple DSP, such as "Mini DSP" (~150$) to equalize HU output, I mean read RTA,
Center freq. for PDC and lower level on this freq.


You have BMW Professional CIC, not just Professional CD Radio right?

No I just have a basic professional HU

[TheBlondeFella]

Originally Posted by Technic

http://www.e90post.com/forums/showpo...1&postcount=10

That ain't spoon feeding buddy ...

[Stream]

Originally Posted by TheBlondeFella

No I just have a basic professional HU

Then how can you regulate PDC and Gong volume? I don't have such options in menu.
E90 05' Prof CD.

[TheBlondeFella]

Originally Posted by Stream

Then how can you regulate PDC and Gong volume? I don't have such options in menu.
E90 05' Prof CD.

It's on the same section as the part that does bass , treble, fader etc

[Stream]

Originally Posted by TheBlondeFella

It's on the same section as the part that does bass , treble, fader etc

Checked menu one more time:

[TheBlondeFella]

Originally Posted by Stream

Checked menu one more time:

If you don't have them, I think it's as you don't have the LCI HU