head unit hiss (sync3)

[SpArKy]

There’s nothing wrong with any of the dsps you listed, they’re all respectable brands. At some point your chasing something that may or may not even be perceptible.

The setup is as follows:

JL Fix82 to flatten the factory signal
Helix DSP for processing
Helix Director to control setups and sub volume
Morel MT350 tweets
Morel CDM880 mids
Dynaudio E650 midbass
Pair of Stereo Integrity BM MK5 subs
3 x Mosconi Zero 3 for front stage
Mosconi Zero 1 for sub duty

I didn’t tune it, but the speakers are getting every bit of power they can take while staying in balance with the weakest link. Theoretical maximum output from each Zero 3 is 270 watts rms per channel at 4 ohms. Given the Morels I used are 6 ohm that reduces the output of the amp to 190 watts or so per channel. Obviously they are turned down substantially from the maximum. I think the Dynaudio E650s are getting the full dose. And I am confident the subs are at their limit just running in stereo off of the Zero 1 with somewhere between 450 and 650 watts rms each.

I’m confident that nothing I added causes the hiss because as soon as you unplug the factory source the hiss goes away.

I bet that sounds awesome.

Where are u taking the factory signal from? High level or low level?

Ur right on there where do u stop bit, with my loud injectors intercooler pumps etc chasing hiss seems a little daft

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[UserName]

I bet that sounds awesome.

Where are u taking the factory signal from? High level or low level?

Ur right on there where do u stop bit, with my loud injectors intercooler pumps etc chasing hiss seems a little daft

Thank you, It sounds incredible.

Low level signal just before factory amp.

Where do you stop? Probably somewhere between what you and I have done would please all but the most hard core golden ears. I initially fretted about the hiss until I realized I don’t just sit in the car while it’s off and no music is playing but the acm is still active. By the time the car is running and the seat coolers kick on with the ac, that hiss is a distant memory.

I plan on upgrading the Mustang’s Helix DSP to a Helix DSP Pro MK3 when it comes out and recycle the Helix DSP into my 30 Plymouth to make that rumble seat rumble in a way that was never intended.

 

[SpArKy]

Thank you, It sounds incredible.

Low level signal just before factory amp.

Where do you stop? Probably somewhere between what you and I have done would please all but the most hard core golden ears. I initially fretted about the hiss until I realized I don’t just sit in the car while it’s off and no music is playing but the acm is still active. By the time the car is running and the seat coolers kick on with the ac, that hiss is a distant memory.

I plan on upgrading the Mustang’s Helix DSP to a Helix DSP Pro MK3 when it comes out and recycle the Helix DSP into my 30 Plymouth to make that rumble seat rumble in a way that was never intended.

Can i ask how u wired in the rcas to the low level?

Just pos to pos. Neg to neg on each? No shield or anything anywhere?

My main gripe is when it goes to hands free phone calls, the hiss with dsp is unbearable. Im sure my non dsp hiss is what u have, i cant believe anyone who's spent what we have on speakers would leave it how mine was

 

[UserName]

Can i ask how u wired in the rcas to the low level?

Just pos to pos. Neg to neg on each? No shield or anything anywhere?

My main gripe is when it goes to hands free phone calls, the hiss with dsp is unbearable. Im sure my non dsp hiss is what u have, i cant believe anyone who's spent what we have on speakers would leave it how mine was

Just like you described is how the wires are hooked up. I have 100% satisfaction with the phone calls. No feedback or anything weird.

 

[SpArKy]

Just like you described is how the wires are hooked up. I have 100% satisfaction with the phone calls. No feedback or anything weird.

Been chatting to some of the gurus on the audio forums and might be on to something with the balanced signal. Ordered a jl convertor. Hoping thats my issue.

 

[Laado]

Been chatting to some of the gurus on the audio forums and might be on to something with the balanced signal. Ordered a jl convertor. Hoping thats my issue.

i think you are right , i also bought a pair of JL C5(6.5”), want to install on the rears, can u help what things i need to install like amp,,ialso want to throw alpine r 12” sub later ..

 

[Racemaster]

Sparky I was thinking........
Where did you grab the turn-on wire for the amp from?I wonder if that is where the noise is getting injected into the amp

 

[SpArKy]

Sparky I was thinking........
Where did you grab the turn-on wire for the amp from?I wonder if that is where the noise is getting injected into the amp

Did it a year ago, cant recall what it was but it was in the loom with all the rear speaker cables. One used by lots of people. Blue/white.

I tried using the remote out from the amp harness but its only 6v (i think) and wont turn on the dsp-408, but will turn on the amps.

There's no noise without the dayton.

Dayton have confirmed that it doesnt accept balanced signals and the output from the headunit is balanced so im working on resolving that as my gut says thats the problem.

 

[Racemaster]

What I did was in the 14 pin plug you will see pin #1 is the audio enable.Pin #14 is the hot positive and pin #11 is the ground that is tied to the instrument panel structure.Those turned on the original amp.Patch those wires into a PAC TR-4.That lets 6 volts in and gives you 12 volts out with a slight delay.
The really cool thing about doing it this way is the audio system still works as stock.Meaning if you shut the key off without opening the door it will still play.And it would rule out using another source for the amp turn on injecting any noise.

 

[SpArKy]

What I did was in the 14 pin plug you will see pin #1 is the audio enable.Pin #14 is the hot positive and pin #11 is the ground that is tied to the instrument panel structure.Those turned on the original amp.Patch those wires into a PAC TR-4.That lets 6 volts in and gives you 12 volts out with a slight delay.
The really cool thing about doing it this way is the audio system still works as stock.Meaning if you shut the key off without opening the door it will still play.And it would rule out using another source for the amp turn on injecting any noise.

i don't think it's the issue, but i certainly like the idea of it behaving like stock and not shutting off as soon as i turn off the ignition. Order placed, cheers

 

[SpArKy]

Issue resolved.

Signal from head unit at amp harness is balanced. Dayton DSP doesn't accept balanced signals.

Bought a JL CL-RLC bass controller which outputs an unbalanced signal. Worked like a charm and i now have an active noise free bass remote as an added bonus!!

 

[StangTime]

Issue resolved.

Signal from head unit at amp harness is balanced. Dayton DSP doesn't accept balanced signals.

Bought a JL CL-RLC bass controller which outputs an unbalanced signal. Worked like a charm and i now have an active noise free bass remote as an added bonus!!

That's awesome! Glad you got it working nicely.

 

[Emilbadal]

It’s great to hear that the notorious hissing noise is being resolved. Can you please clarify what you mean by “ the signal from the headunit is balanced”? I did a small research about the balanced and unbalanced signal, and the read it said that for balanced signal there need to be 3 wire per channel to work as a balanced signal. I’d appreciate it if you could clarify this.

 

[SpArKy]

It’s great to hear that the notorious hissing noise is being resolved. Can you please clarify what you mean by “ the signal from the headunit is balanced”? I did a small research about the balanced and unbalanced signal, and the read it said that for balanced signal there need to be 3 wire per channel to work as a balanced signal. I’d appreciate it if you could clarify this.

i don't claim to be an expert on it, but the main difference is that in a balanced setup there are 2 cables carrying a signal, unbalanced there is only 1. In our cars both the + and - cables at the factory amp carry a signal. Remember there is no RCA cable in the factory setup so the 3 wires vs 2 wires is not how it was designed to be transmitted.

 

[Emilbadal]

Oh Okay, that makes sense. I was under the impression that once the mode of the output of the HU was changed from speaker line to line level output in Forscan, it was converted into unbalanced outputs for some reason. Thanks for clarification.

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