Helix Soundbox Upgrade Information Post!

[patcfly]

I'm not sure if anyone has drawn up or found a pin out for the helix side of the harness, but like you said it's basically 4 pairs of black and red wires (so - black and + red).

For the Helix box, remember that it is also ported. There is a slot port next to the amp recess.

I've thought about upgrading subs in the helix box to something like the infamous Tang Band W5 sub (https://www.parts-express.com/tang-band-w5-1138smf-5-1-4-paper-cone-subwoofer-speaker--264-917) except it's only a 4 ohm SVC. Any other smaller subs are similarly wrong in spec, either dual 4ohm only or single 4 or 2ohm. Anything except for a pair of 2ohm DVC subs will half your output at least.

What you're talking about doing with putting the wires together won't work (the amp will not like that), and I don't believe traditional "bridging" of the helix amp will work. None of their documentation says anything about bridging, but it's not designed to do that. I doubt that feature was added to something that is such a specific DSP/Amp meant to be paired to one specific sub. Even the PP50/52 specs don't state anything about bridging the sub outputs. I'm 99% sure the Helix amps are setup as an 8 channel amp effectively (4 full range and 4 sub channels), with 2 ohms per channel being the lowest stable per channel.

Your best option? Buy an inexpensive mono amp with speaker level inputs and an auto turn on circuit. Pin out 2 of the helix sub outputs to the new amp and you're done. That does mean wiring power to your trunk, but that would put as much power to whatever woofer you'd want to use while still using the DSP.

I just emailed audiotec fishcher asking if the subwoofer outs on the pp 62dsp supported bridging - the answer is a flat no. The helix dsp is basically a stripped down pp 62dsp as far as I can tell. It might work, but I am not going to risk it. So I agree with you that a cheap monoblock amp would be the way to go.

Also, worth noting but to everyone else: the "gain" knob is for input sensitivity on the pp 62dsp. I would HIGHLY doubt that it is a gain control for the sub only on the helix dsp. Raise that too high and you risk damaging the DSP I think.

On another note: this thread is super helpful. I have a 2017 tiguan 4motion that i just put the helix sub in. I am replacing my door speakers (front and back, woofers and tweeters) with polk db6501 and getting an under-floor sub enclosure so I can keep my spare tire and have a box. The tiguan floor is much higher than the non-4motion VW hatchbacks, sedans, and wagons, so mounting the helix sub box on top or below the spare tire is definitely not possible. The box is a sealed enclosure so that will likely change the dual sub output profile quite a bit.

I also have a set of 150 hz crossover bass blockers on their way to me that will go in line before the crossover for the polk components. Goal is to keep the doors solely focused on mids and highs.

I am going to do fronts first, and then test sound profile compared to the rear doors so I can do a bit of A/B testing and will report back here (perhaps also with some build pictures).

Thanks for all the great info everyone!

 

[flipflp]

Thanks, I've played with that pot and I have it at around 50%. I noticed distortion all around if I raise it higher and up bass levels at the head unit. I'm looking for a solution that will allow good bass from the drivers and deep bass from the sub .. I can't seem to get this with the existing Helix setup. Thoughts ?

From my experience, the helix runs full range to the 4 channels PLUS lower frequencies to the sub. That is pretty well maxed out unless you swap the subs. Only so much two 6" DVC subs can do with the space they are given.

What I've been researching is adding this amp: https://www.audiocontrol.com/car-audio/power-amplifiers/acm-1300/
Auto power on, crossovers, their AccuBass to bring back frequencies below ~40hz that get cut by OEM head units, and 300 real watts of power to put to basically any sub setup you want.

 

[flipflp]

I just emailed audiotec fishcher asking if the subwoofer outs on the pp 62dsp supported bridging - the answer is a flat no. The helix dsp is basically a stripped down pp 62dsp as far as I can tell. It might work, but I am not going to risk it. So I agree with you that a cheap monoblock amp would be the way to go.

Also, worth noting but to everyone else: the "gain" knob is for input sensitivity on the pp 62dsp. I would HIGHLY doubt that it is a gain control for the sub only on the helix dsp. Raise that too high and you risk damaging the DSP I think.

On another note: this thread is super helpful. I have a 2017 tiguan 4motion that i just put the helix sub in. I am replacing my door speakers (front and back, woofers and tweeters) with polk db6501 and getting an under-floor sub enclosure so I can keep my spare tire and have a box. The tiguan floor is much higher than the non-4motion VW hatchbacks, sedans, and wagons, so mounting the helix sub box on top or below the spare tire is definitely not possible. The box is a sealed enclosure so that will likely change the dual sub output profile quite a bit.

I also have a set of 150 hz crossover bass blockers on their way to me that will go in line before the crossover for the polk components. Goal is to keep the doors solely focused on mids and highs.

I am going to do fronts first, and then test sound profile compared to the rear doors so I can do a bit of A/B testing and will report back here (perhaps also with some build pictures).

Thanks for all the great info everyone!

That is what I figured on the bridging, thank you for confirming!

There have been a lot of people in this thread that have agreed that the potentiometer on the Helix effects only the sub but it's possible it's just effecting the gain overall. The sub would just be the most noticeable. The biggest reason I think the Helix is going to be different from a PP52/62DSP in that regard is because it's an OEM install part, so they would know what the output of the headunit is. There would be no subwoofer level control like the Fender stereos have, so it would make sense for them to include one on this application.

I should have a set of 250uf caps delivered to me today from Parts Express (~150hz blocker on 4 ohms), my door speakers definitely need to calm the hell down with bass. Hopefully that lets the sub work a bit more. That much bass in the doors just asks for rattles anyway.

 

[patcfly]

From my experience, the helix runs full range to the 4 channels PLUS lower frequencies to the sub. That is pretty well maxed out unless you swap the subs. Only so much two 6" DVC subs can do with the space they are given.

What I've been researching is adding this amp: https://www.audiocontrol.com/car-audio/power-amplifiers/acm-1300/
Auto power on, crossovers, their AccuBass to bring back frequencies below ~40hz that get cut by OEM head units, and 300 real watts of power to put to basically any sub setup you want.

Do you have any references that the head unit cuts out all sub 40hz signal?

 

[flipflp]

Do you have any references that the head unit cuts out all sub 40hz signal?

Not something specific to VW or the Helix, but it's something that is believed to exist in many OEM head units to reduce the chance of damage to OEM speakers. That's why there are "bass reconstruction" or enhancement circuits in many of the factory upgrade amps, DSPs, etc.

I'm not sure it's a hard cut at 40hz either, but potentially a 12db octave type high pass for protection.

 

[patcfly]

Not to be too contrarian and I know I'm new here... but that sounds like making something from nothing. If the head unit is outputting only 40hz and high signal, then nothing you add in after the head unit will "restore" that information. It will just be gone forever. The only thing you can do is assume that if a note hits 40hz that the sub should play all frequencies below that as well OR perhaps determine the harmonics of the signal at that point and time and then add in the lower notes below 40hz.

Still, that would be a big assumption and would never be perfect.

Also: why would a manufacturer want to remove signal below 40hz? What would be the motivation? To not bottom out the woofers in the doors and cause premature failure? That sounds like something a $1 capacitor in line to the speaker could fix easier?

Idk - it just seems like something an oscilloscope would be able to easily prove or disprove.

Much more likely the case is that the stock head units just dont have good amplification circuits and thus can't drive aftermarket speaker woofers well enough to cause any meaningful reproduction of 40hz and lower tones. Adding an amp in line to the door speakers would take that problem and correct it, no?

 

[flipflp]

Not to be too contrarian and I know I'm new here... but that sounds like making something from nothing. If the head unit is outputting only 40hz and high signal, then nothing you add in after the head unit will "restore" that information. It will just be gone forever. The only thing you can do is assume that if a note hits 40hz that the sub should play all frequencies below that as well OR perhaps determine the harmonics of the signal at that point and time and then add in the lower notes below 40hz.

Still, that would be a big assumption and would never be perfect.

Also: why would a manufacturer want to remove signal below 40hz? What would be the motivation? To not bottom out the woofers in the doors and cause premature failure? That sounds like something a $1 capacitor in line to the speaker could fix easier?

Idk - it just seems like something an oscilloscope would be able to easily prove or disprove.

Much more likely the case is that the stock head units just dont have good amplification circuits and thus can't drive aftermarket speaker woofers well enough to cause any meaningful reproduction of 40hz and lower tones. Adding an amp in line to the door speakers would take that problem and correct it, no?

No worries, I was looking for an article or something more specific on this. Couldn't find anything other than anecdotal stuff regarding bass being limited at higher volumes, from companies that sell units that "fix" that specifically haha: https://www.audiocontrol.com/knowledge-base/how-do-i-set-accubass/

Since most OEM stereos can't produce 40hz (or even 50 or 80 or higher, I just tossed out 40hz) what I have read was that as volume goes up, bass rolls off to protect the OEM speakers. That roll off doesn't mean that the sound information is gone, it's just a progressive roll off as the volume increases. A simple cap would mean that those frequencies would NEVER be produced, even at lower volumes when the speakers aren't at risk. These enhancement circuits can catch frequencies below 40 hz at lower volumes and "restore" them to the original source levels.

 

[patcfly]

No worries, I was looking for an article or something more specific on this. Couldn't find anything other than anecdotal stuff regarding bass being limited at higher volumes, from companies that sell units that "fix" that specifically haha: https://www.audiocontrol.com/knowledge-base/how-do-i-set-accubass/

Since most OEM stereos can't produce 40hz (or even 50 or 80 or higher, I just tossed out 40hz) what I have read was that as volume goes up, bass rolls off to protect the OEM speakers. That roll off doesn't mean that the sound information is gone, it's just a progressive roll off as the volume increases. A simple cap would mean that those frequencies would NEVER be produced, even at lower volumes when the speakers aren't at risk. These enhancement circuits can catch frequencies below 40 hz at lower volumes and "restore" them to the original source levels.

It's certainly not impossible. Although again, shitty amplification would naturally have roll off on the low frequencies as volume levels increase. Anyways, that lc2i seems to just identify at what point the low frequency roll off starts at and then compensates for it with effectively an equalizer that engages only at the volume level where the roll off starts.

 

[flipflp]

It's certainly not impossible. Although again, shitty amplification would naturally have roll off on the low frequencies as volume levels increase. Anyways, that lc2i seems to just identify at what point the low frequency roll off starts at and then compensates for it with effectively an equalizer that engages only at the volume level where the roll off starts.

AudioControl sorta refers to their AccuBass as a bass boost, but it also has a threshold to set if your system does roll off. That way a bass gain can be set to increase the volume of rolled off frequencies only. It's a neat little trick if you're really cranking an upgraded OEM stereo/speakers.

I don't officially know if VW systems NEED bass correction, but a few people have used LC2i units to add a separate subwoofer and amp using the helix outputs.

Here's StealthGTIs post on his website about his sub upgrade using the LC2i: https://stealthgti.com/electronics-suite/

 

[patcfly]

AudioControl sorta refers to their AccuBass as a bass boost, but it also has a threshold to set if your system does roll off. That way a bass gain can be set to increase the volume of rolled off frequencies only. It's a neat little trick if you're really cranking an upgraded OEM stereo/speakers.

I don't officially know if VW systems NEED bass correction, but a few people have used LC2i units to add a separate subwoofer and amp using the helix outputs.

Here's StealthGTIs post on his website about his sub upgrade using the LC2i: https://stealthgti.com/electronics-suite/

Ya i found stealthgti's page through search engines. I had a strong feeling the helix box + spare tire would not fit under the baord in my tiguan. The floor barely clears the spare tire alone. So, I started looking for subwoofer enclosures that sit next to the spare tire and his site came up.

Anyways, after learning that the DSP can't run in a bridge config (or at least the manufacturer says you shouldn't) I am going to just have a box built with two 6" sub holes and hope for the best. $255 is a lot for a sub box for 6" subs but... wife acceptance factor is real.

 

[flipflp]

Ya i found stealthgti's page through search engines. I had a strong feeling the helix box + spare tire would not fit under the baord in my tiguan. The floor barely clears the spare tire alone. So, I started looking for subwoofer enclosures that sit next to the spare tire and his site came up.

Anyways, after learning that the DSP can't run in a bridge config (or at least the manufacturer says you shouldn't) I am going to just have a box built with two 6" sub holes and hope for the best. $255 is a lot for a sub box for 6" subs but... wife acceptance factor is real.

His sub upgrade had some notes on the LC2i for our discussion, he has changed that setup since I believe.

Yeah unfortunately on some installs you have to pick between a sub and a spare. Short floor models like AWD Tigs or Rs are definitely that way.

Should be able to create a box that would horseshoe around the spare with similar volume. Don't forget the stock helix is a ported box, I added a link from a few pages back now to the main post with the sub's specs as well.

 

[patcfly]

Ya I have the specs. I know the stock helix box is ported and they sub specs recommend not running sealed. However.... somethings gotta give. I am ordering one of these tonight. http://www.uberstealthaudio.com/store/p10/VW_Tiguan.html

I don't think I will go through the trouble of porting it unless i get it installed and it sounds bad.

 

[Nashvillain]

Thank you for this thread! Installed about 2 weeks ago, great improvement to stereo output (waiting for dongle for upgrade to soundstage).

I would recommend also wrapping the last foot of cable nearest the head unit/adapters with electric tape/shielding. I encountered a short from wire exposure when attempting to place head unit back into glovebox housing numerous times, that went through a couple 20 amp fuses. Also helps to pull cable out of side of dashboard as placing head unit back into housing.

 

[StealthGTI]

Thanks for the mention about my site, guys!

What I've been researching is adding this amp: https://www.audiocontrol.com/car-audio/power-amplifiers/acm-1300/
Auto power on, crossovers, their AccuBass to bring back frequencies below ~40hz that get cut by OEM head units, and 300 real watts of power to put to basically any sub setup you want.

If I was doing it all over again, THIS is the route I would take, plus adding the ACR-1 for remote subwoofer level control. Sure, it's not going to win any sound-offs; but 300 watts to a good subwoofer is a nice accent!

 

[flipflp]

Thanks for the mention about my site, guys!



If I was doing it all over again, THIS is the route I would take, plus adding the ACR-1 for remote subwoofer level control. Sure, it's not going to win any sound-offs; but 300 watts to a good subwoofer is a nice accent!

I might regret posting this if they are gone before I can get one, but there is an eBay seller with the 1st Gen version of that amp that is lacking the remote level control for CHEAP:
https://www.ebay.com/itm/AudioContr...ro-Amplifier-300W-No-ACR-1-Port-/283596041414

As nice as it would be to have sub level control...for half price...that is a bargain. Throw a cheap 8 gauge amp power kit at it and the 8 pin power supply extender to chop up and that is all you need.