[simoneves]

Sourcing an input to the amp from a speaker-level signal or a line-level signal doesn't mean they can't be mixed, as both end up as line-level before being digitized, and all the mixing happens in the digital world. The topology would be the same if the outputs of the ASD were line-level. There just wouldn't then be the option for BMW to be cheapskates and use JUST that module in base model cars!

As for the idea in general, I just read the manual for the amp software again, and it seems that it might not be possible after all, as apparently the "patch bay" of inputs to outputs is the first thing in the chain, and then all the processing adjustments are per output (eight powered, two line-level). This means that you can't apply different EQ to two inputs and THEN mix them together to an output, which is what would be required for my idea to work properly (full-range music plus low-passed ASD sound). You can adjust the simple proportion of combinations of inputs to each channel in 10% steps (e.g. channel 1 = 80% of input 1 plus 20% of input 5) so you could roughly balance the ASD level against the music level, but you couldn't EQ them differently, so you wouldn't be able to remove the hiss from ONLY the ASD component without also affecting the music component. In other words, you wouldn't be able to remove the hiss, which means you're not really any better off. You could adjust the ASD sound LEVEL without compromising the rest of the gain structure, but that's not really enough to make it worth doing, at least not in my book.

Shame.

[simoneves]

I e-mailed both Technic and @Nelson about this, but they have yet to respond. I also sent them the follow-up about my conclusion that it probably won't work, so perhaps that's why! :\

It makes sense that the DSP signal flow in the amp would be like it is, since the EQ etc. is really there to adjust for the individual speakers and not just for the overall tone of the sound. It's just a shame that it doesn't allow you to do *both*, as it really wouldn't be any harder in DSP terms, unless the DSP power is already maxed out. Maybe Audiotec-Fischer could even add it as a firmware update. Even just some simple filtering options (just an LPF would be enough for this) on each input *before* the patch-bay would make it work.

[Viffermike]

Originally Posted by simoneves

Sourcing an input to the amp from a speaker-level signal or a line-level signal doesn't mean they can't be mixed, as both end up as line-level before being digitized, and all the mixing happens in the digital world. The topology would be the same if the outputs of the ASD were line-level. There just wouldn't then be the option for BMW to be cheapskates and use JUST that module in base model cars!

As for the idea in general, I just read the manual for the amp software again, and it seems that it might not be possible after all, as apparently the "patch bay" of inputs to outputs is the first thing in the chain, and then all the processing adjustments are per output (eight powered, two line-level). This means that you can't apply different EQ to two inputs and THEN mix them together to an output, which is what would be required for my idea to work properly (full-range music plus low-passed ASD sound). You can adjust the simple proportion of combinations of inputs to each channel in 10% steps (e.g. channel 1 = 80% of input 1 plus 20% of input 5) so you could roughly balance the ASD level against the music level, but you couldn't EQ them differently, so you wouldn't be able to remove the hiss from ONLY the ASD component without also affecting the music component. In other words, you wouldn't be able to remove the hiss, which means you're not really any better off. You could adjust the ASD sound LEVEL without compromising the rest of the gain structure, but that's not really enough to make it worth doing, at least not in my book.

Shame.

Indeed. Though frankly it does make sense from a signal processing standpoint, particularly if you're balancing and mixing two inputs to a channel. In most applications, you'd want the processing to affect the sum of inputs instead of the parts, which would decrease the amount of EQ and adjustment needed to make the outputs sound good.

Looked at another way: you can feed more than one signal (i.e., instrument) to many stage amps these days. But almost no one does that because the processing would need to be shared by both instruments simultaneously. That wouldn't make ANY musician (or sound engineer, or fan) happy. It's been done before to achieve a specific sound, but very, very rarely.

[simoneves]

Originally Posted by Viffermike

Looked at another way: you can feed more than one signal (i.e., instrument) to many stage amps these days. But almost no one does that because the processing would need to be shared by both instruments simultaneously. That wouldn't make ANY musician (or sound engineer, or fan) happy. It's been done before to achieve a specific sound, but very, very rarely.

Exactly. I was making assumptions based on my experience with audio mixers in music and theatre, where you generally DO want to process the various inputs differently (vocal and instrument EQ/compression/whatever) before mixing them, and then apply some extra overall processing to the mixed output (room EQ, alignment delays).

I still think there's room for such a device to have basic pre-mixer input processing as well as output processing, but I guess even cars generally only have one source device.

I guess it wouldn't be too hard to make a small passive box which takes the ASD outputs, applies LPF (to kill the HF hiss), and converts to line-level, to stick in between the ASD and inputs 5-8 of the amp in my proposal. This might be as simple as a commercial four-channel LOC with a simple series-resistor/parallel-capacitor network on each output, or maybe there are LOCs with filters built in?

Still not sure I care enough to do it, though.

[MASHCT]

I installed a JL Audio xd600/6d v2 today. Noticeable hiss with volume turned down; can't hear it while playing music at any volume level.

I have the Technic harness installed.
Input sensitivity on the amp is set pretty low (yet I am still managing volume that is far better than the stock amp). Line level is also set to low. HPF on for front & rears, set at 80. Woofer LPF set at 80.

Bass in the stock under seat woofers is TONS better; punchier, deeper & way more noticeable. will likely keep them now. And even the HK speakers sound clearer with better frequency response; Ning seems "missing" in the sound as it did with the stock amp. No need to disconnect the center speaker - it's not on at all with an aftermarket amp. (I am awaiting delivery of a set of CDT Audio components for the front; have a set of Morel Tempo coax for the rear.)

I connected th amp ground to the ground point on the left upper side. Hissed/slight whine present. Then connected the ground directly to the battery. still heard the hiss/slight whine. This suggests to me the noise is not a ground issue.

I also ran the power wire about two inches away from the speakers wires that snake through the wheel well so I doubt I am picking up any kind of noise there. Besides, the amp cable has some THICK insulation on it.

If thre was one thing I noticed with the HK system is that no matter how much I cranked th system, it never seemed to be as loud as it should be or as expected. The music never had any punch or vibrancy. I am betting the gain on the HK amp was very low, such that the hiss/noise was not very noticeable. Add a higher power amp & voila - the noise is amplified & now noticeable.

I am wanting to try tuning the JL amp's level switch to "high" based on what I've read in this post about the ASD module being an amp or booster & possibly outputting speaker level signals, but unsure what that will do to the amp if it's really line level.

I am wondering it some kind of I -line noise filter might help.

Any ideas?

Originally Posted by simoneves

Exactly. I was making assumptions based on my experience with audio mixers in music and theatre, where you generally DO want to process the various inputs differently (vocal and instrument EQ/compression/whatever) before mixing them, and then apply some extra overall processing to the mixed output (room EQ, alignment delays).

I still think there's room for such a device to have basic pre-mixer input processing as well as output processing, but I guess even cars generally only have one source device.

I guess it wouldn't be too hard to make a small passive box which takes the ASD outputs, applies LPF (to kill the HF hiss), and converts to line-level, to stick in between the ASD and inputs 5-8 of the amp in my proposal. This might be as simple as a commercial four-channel LOC with a simple series-resistor/parallel-capacitor network on each output, or maybe there are LOCs with filters built in?

Still not sure I care enough to do it, though.

[DKX4///M]

Two things here that confuse me...

I understand that ppl are getting a hiss and the concept of trying to use a LPF to filter it. /But ASD has a strong low freq output. i K.I.S and just throw a high quality LOC /Line driver, Bass restoration processor and a powerful well matched sub and amp combo. Rockford P3 pushing 1200 RMS which is its peak rating...levels on LOC?Driver down and gain at 0...

The ASD's output does not vary with speed, radio volume, etc. The only thing that does have a major affect is mode...Comfort mode brings it MUCH lower...Sprt n Sprt + =same volume...And its the loudest at low RPM's....higher up the engine takes over and the ASD goes completely away.

Secondly, saying it only goes to the rear speakers....based on the 2016 2 series wiring diagram I tapped the underseat sub wires (@ the stock amp) and they are clearly the correct wires bc the oem sub wires in BMW I've noticed are thicker than the rest of the speakers...

My coder claimed he turned it down but it was not possible to disable it. Clearly he's wrong.

Ive been attempting to order the harness through emails but am having trouble w long response times...

[Viffermike]

Originally Posted by DKM3Power

Two things here that confuse me...

I understand that ppl are getting a hiss and the concept of trying to use a LPF to filter it. /But ASD has a strong low freq output. i K.I.S and just throw a high quality LOC /Line driver, Bass restoration processor and a powerful well matched sub and amp combo. Rockford P3 pushing 1200 RMS which is its peak rating...levels on LOC?Driver down and gain at 0...

The ASD's output does not vary with speed, radio volume, etc. The only thing that does have a major affect is mode...Comfort mode brings it MUCH lower...Sprt n Sprt + =same volume...And its the loudest at low RPM's....higher up the engine takes over and the ASD goes completely away.

Secondly, saying it only goes to the rear speakers....based on the 2016 2 series wiring diagram I tapped the underseat sub wires (@ the stock amp) and they are clearly the correct wires bc the oem sub wires in BMW I've noticed are thicker than the rest of the speakers...

My coder claimed he turned it down but it was not possible to disable it. Clearly he's wrong.

Ive been attempting to order the harness through emails but am having trouble w long response times...

Problem 1: Well, it's system hiss generated by the ASD module, which isn't necessarily limited to the upper limits of the frequency spectrum, as you now know. A LPF doesn't make sense to eliminate that, particularly with the bass frequencies that are present.

Furthermore, that the ASD has been earmarked as the cause of the system noise means the best way to defeat it is to 'cut the head off the snake', i.e., the module itself. The problem with that is that it's integrated into iDrive as well as the HU -- the volume difference between Comfort and Sport/Sport+ is proof of that -- and simply removing the module kills the entire system. That integration is also why coding doesn't work completely; coding may very well remove the active sound itself but it does not remove the system noise. It's basically like turning the volume down to 0 on an amp: inputs can't be heard, but the amp's noise floor, EMF, etc. still can be.

The harness basically routes the output of the ASD module back to itself. I'm sorry Technic hasn't responded; I'm sure he will, and I'm sure he has a good reason for the delays. (I hope; I still need to order a harness from him!)

Problem 2: I'm not sure what you're saying; ASD is primarily dependent on the rear speakers. That said, the rears' output is somewhat integrated into the subs' output just as the fronts are. The level of the subs seems to be highest when the fader is a hair forward of split between front and back; fading to the front gradually lowers the subs' level relative to the fronts, while fading to the back drastically lowers the subs' level relative to the rears. ASD volume stays consistent and doesn't rise or fall with HU system volume probably because the module feeds a constant wattage to the amp -- wattage that never changes, even when the HU is turned off. This is most likely what we're all hearing as 'system hiss' and also why it can't be eliminated by coding -- ASD volume is controlled by iDrive, which cannot be disabled and keeps the amp on even when the HU is turned off to enable 'car sounds', telephonics, etc.

[DKX4///M]

Originally Posted by Viffermike

Problem 1: Well, it's system hiss generated by the ASD module, which isn't necessarily limited to the upper limits of the frequency spectrum, as you now know. A LPF doesn't make sense to eliminate that, particularly with the bass frequencies that are present.

Furthermore, that the ASD has been earmarked as the cause of the system noise means the best way to defeat it is to 'cut the head off the snake', i.e., the module itself. The problem with that is that it's integrated into iDrive as well as the HU -- the volume difference between Comfort and Sport/Sport+ is proof of that -- and simply removing the module kills the entire system. That integration is also why coding doesn't work completely; coding may very well remove the active sound itself but it does not remove the system noise. It's basically like turning the volume down to 0 on an amp: inputs can't be heard, but the amp's noise floor, EMF, etc. still can be.

The harness basically routes the output of the ASD module back to itself. I'm sorry Technic hasn't responded; I'm sure he will, and I'm sure he has a good reason for the delays. (I hope; I still need to order a harness from him!)

Problem 2: I'm not sure what you're saying; ASD is primarily dependent on the rear speakers. That said, the rears' output is somewhat integrated into the subs' output just as the fronts are. The level of the subs seems to be highest when the fader is a hair forward of split between front and back; fading to the front gradually lowers the subs' level relative to the fronts, while fading to the back drastically lowers the subs' level relative to the rears. ASD volume stays consistent and doesn't rise or fall with HU system volume probably because the module feeds a constant wattage to the amp -- wattage that never changes, even when the HU is turned off. This is most likely what we're all hearing as 'system hiss' and also why it can't be eliminated by coding -- ASD volume is controlled by iDrive, which cannot be disabled and keeps the amp on even when the HU is turned off to enable 'car sounds', telephonics, etc.

s
I keep balance/Fade in the middle. Based on your post ill try putting the fader slightly forward...But im waiting for the harness...My coder said it coudnt be coded out....And I hear different things from everyone...

To me without thd sub i cant hear it...im also goign def from djing for years...I wish the harness ppl would answer email .

[wntrsnowg]

Originally Posted by MASHCT

I installed a JL Audio xd600/6d v2 today. Noticeable hiss with volume turned down; can't hear it while playing music at any volume level.

I have the Technic harness installed.
Input sensitivity on the amp is set pretty low (yet I am still managing volume that is far better than the stock amp). Line level is also set to low. HPF on for front & rears, set at 80. Woofer LPF set at 80.

Bass in the stock under seat woofers is TONS better; punchier, deeper & way more noticeable. will likely keep them now. And even the HK speakers sound clearer with better frequency response; Ning seems "missing" in the sound as it did with the stock amp. No need to disconnect the center speaker - it's not on at all with an aftermarket amp. (I am awaiting delivery of a set of CDT Audio components for the front; have a set of Morel Tempo coax for the rear.)

I connected th amp ground to the ground point on the left upper side. Hissed/slight whine present. Then connected the ground directly to the battery. still heard the hiss/slight whine. This suggests to me the noise is not a ground issue.

I also ran the power wire about two inches away from the speakers wires that snake through the wheel well so I doubt I am picking up any kind of noise there. Besides, the amp cable has some THICK insulation on it.

If thre was one thing I noticed with the HK system is that no matter how much I cranked th system, it never seemed to be as loud as it should be or as expected. The music never had any punch or vibrancy. I am betting the gain on the HK amp was very low, such that the hiss/noise was not very noticeable. Add a higher power amp & voila - the noise is amplified & now noticeable.

I am wanting to try tuning the JL amp's level switch to "high" based on what I've read in this post about the ASD module being an amp or booster & possibly outputting speaker level signals, but unsure what that will do to the amp if it's really line level.

I am wondering it some kind of I -line noise filter might help.

Any ideas?

Bumping this thread, looking for a solution. I just installed my JL xd600/6 v2 last night and have the same problem. I adjusted the amp gain based on the JL instructions, connected the speakers and the hiss was so loud!! I had to back off the amp gain on the front and rear speaker channels from the recommended setting to lower the hiss to something tolerable. Not pleased at all

[M2Rob]

I would like to know the same things. I have an 18 M2 with the HK system and am getting ready to order the following (tomorrow):

ASD delete cable from TechnicPNP
Add and amp cable from technicPNP
JL Audio 600/6 or 800/8 or the new VX800/8
Maybe a 2ohm under seat replacement
MAYBE an Audio Control line driver (for hiss if you guys agree)

I want the system to feel STOCK. The system in my Audi (because of the stupid MOST system, long story) turned on late, turned off late, had a pop when turning off, etc. Sounded great, but I always knew it was aftermarket. So, no hiss and normal dings/bells are important to me.

Here are my thoughts, and VifferMike, I would LOVE your input/expertise here:

Cables - from TechnicPNP for stock look and feel, even though I may modify the ASD cable with a switching on/off capability.

JL amps - the 600/6 is the standard, if I can fit the 800/8 in the stock location, I could use the extra 200 watts to run a JL 10in box I have left over to drive just the bottom octave for that extra feel. the new VX800/8 will fit (It is stupid small), give me DSP control, and allow me to use my JL 10. But that price, damn!

Replacement under seats - I have this originally planned, but I am hearing a lot of people say with a real amp, it may not be necessary. so, I am torn on this. I like a hard hitting mid bass, and I just don't feel the stock subs are gonna meet this requirement.

And finally the Line Driver - I have read these posts, especially the 6,000 page one, and it appears this hiss might be related the BMW's low level output and ASD, and its attempt to cover a low quality source unit. I am an old school car audio guy, and the gains on amps are matching tools, not volume controls for problems. So, my thought is, add a quality line driver to bring the signal to a solid 2 volts, allow the amp to amplify a quality signal, and maybe the hiss would be gone!?

I am ordering all of this this weekend, so, hopefully you guys can give me some feedback. I will post pics and opinions of the install in the next week.

Thanks in advance!