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I'm not sure why I never seen or read into this before, but this totally makes sense and is something I need to look into.

Currently using Optical from an AP4 to DSP.2, and noticed that when setting the gains I was able to crank them pretty good. One thing I noticed too (outside of the slight noise I have with no signal playing) is that my system still has noticeable volume even at the lowest setting on the HU. My guess is that this is due to the relatively high amplifier gain I'm using with the current 0.0dB setting on the digital input?
Keep in mind that these "electronic" gain controls will only show up in the DSP PC-Tool application if you go to the DCM screen and "enable" the "Source Volume Control" setting.

So if you don't see them, check that setting in the DCM screen.

Adjusting the digital gain/amp gain may help with your issue - not 100% sure. Can always try it and see what happens.

Also - if you happen to be using a PAC AmpPro 4 device in your setup, it also allows you to adjust the "Minimum Volume Level" (basically the volume level at head-unit volume 1). Again, just in case you happen to use an AmpPro. :)
 

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Discussion Starter #23
That's what made me question it... I had the gains so high I was getting noise... changed the input gain and dropped the amp gains.. and bingo

FYI - I messaged Doug at AF and he confirmed there is no harm running +10db on the digital input gain. He personally does the same thing. He said the reason it's there is if you wanna level match to another source
 

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Yes, using the AP4-GM61. And yea, I'll have to check the minimum volume level again. Yep, have the settings on the Digital Routing tab next to the "Digital" label.

Another thing I'll mention is that I actually did utilize the settings for the Signal Detection Setup that Bman mentioned. I noticed that at times the Helix would release the optical signal from the AmpPro even though it's configured to have priority. I had noticed this once while I was on a phone call and was put on hold, basically it took the system a bit to fire back up whenever they came back on the line.
 

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Which DSP do you have? WIth the newer ACO-based DSPs, there is a mobile app that allows you to adjust all of the volumes. Check the volume levels in the app to make sure they are appropriate. You may just need to turn the master volume all of the way up in the app to get things working like you want with the URC-3.

When I first installed my DSP.3, I had to install the app in order to get ANY sound - found the "Master" volume was all of the way down in the app (I don't have a URC connected)...
Was unaware of a Helix app... Gotta link or what's it called? Thanks
 

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Actually, I mis-stated things. The app is only if you are using the Helix Wifi-Adpater. If you use the Wifi-Adapter, there is a mobile app called Helix Wifi Control App - it is in the Google Play store for Android (not sure about Apple, but I'm assuming there is a version for it as well).

Basically, it performs all of the functions of the Director.

Sorry for the mis-information. I sometimes forget that no everyone uses the Helix wifi adapter (but you should!!!). :)
 

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Yep, the WiFi Control App is only if you have the WiFi adapter. The DSP's and amps cannot do this on their own. The app is basically a poor man's Director if you look at all of the different things you can adjust on it (pretty cool). Since I don't foresee myself adjusting sub volume very often, I will use the Control App to do this from my phone if I have to and may use my URC.3 to control Master Volume and Digital Volume. However, I also have the HEC BT so things are going to get complicated because I have to be able to adjust the volume of that also. I am keeping my stock HU, which basically sucks, but I want to keep it for phone calls and connect my phone to the vehicle's BT for that function. I will be running the front high-level signal from my stock HU to the P Six for this function and figure out if I can set that function to take priority when I make or receive a phone call. My main source of music will come from a DAP (Fiio X7 Mk2) using the P Six's optical input and then have the HEC BT for a 3rd source in the event my wife wants to hook her phone up to the system to play her music while she's riding along with me (she usually doesn't drive my car otherwise).

I may be able to set the master volume to a moderate level for phone calls using the Control App and then use the URC.3 for adjusting Digital and HEC volumes, with the mode button used to switch between the two. Of course this is all where properly setting up the auto-detect settings comes into play.
 

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Thanks for the reply! I went ahead and maxed mine at 10db but then thought I better find out for sure. I have plenty of volume and zero clipping. I'm kind of wondering why there is even a setting if a digital signal doesnt clip?
You’re not quite correct, a digital signal in itself doesn’t clip as it’s at 0db at all times unless a volume control is present on the source in which bit depth is reduced to attenuate volume, hence people saying it will never clip

however... the gain you speak of is for matching levels with other sources, you can however clip the inputs of the dsp with a digital signal as the gain will be applied after the signal has entered the dsp and will try to boost everything by 10db, even a 0db sine wave for example, so applying 10db of gavin to the digital input may very well be negatively effecting your sound

in other words Doug may have a less than perfect digital signal coming in, (he expressly stayed that digital signals are often quieter than analogue... this isn’t typical of my experiences with digital devices) for example if it’s from a most network that’s badly implemented, you cannot just say he boosts it 8db... so I can, that’s not how it works... that’s like saying your mate runs his gains at half on his amp (he has a 2v signal) so you can (you may have a 5v signal, the two settings would be very different!

I hope this helps understand what you’re saying is correct, but not in what you’re doing 👍🏼
 

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Regarding the digital volume... I originally assigned remote #1 to digital volume and #2 to sub level. I had almost no volume. Then I changed #2 to master volume. Then I had full volume and both knobs adjust the volume.

Which is pointless... How can I use sub level while using digital volume?
Set digital volume in the software... this is how it needs to be for best signal to noise... and use master volume and sub volume on the urc.3 as that will also control any digital sources also at the output of the processor where you need it... master vol is just that, it controls the output of everything, if you’re playing a digital source the Master volume will effect it, I don’t see the benefit of digital volume at all
 

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Discussion Starter #30
Thanks for the information! Doug also mentioned to me that digital sources are often lower db. I'm new to using a digital source and still learning.

I'm currently using a Filo x5 line out directly to the Helix RCA input. This is temporary until I install a coax to optical converter.

I have a mixture of 320 MP3's and 24 bit FLAC. What is the best method to properly set the input gain?
 

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Discussion Starter #31
When I started this thread I was streaming Tidal from my phone to a USB to optical converter. So right now I'm just using the analog inputs. When using analog I have the input gain set at +2.7db. I set this using a DD1 and was able to boost a little with no clipping
 

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Set digital volume in the software... this is how it needs to be for best signal to noise... and use master volume and sub volume on the urc.3 as that will also control any digital sources also at the output of the processor where you need it... master vol is just that, it controls the output of everything, if you’re playing a digital source the Master volume will effect it, I don’t see the benefit of digital volume at all
When you say, "Set digital volume in the software", do you mean in the IO page that we discussed previously in this thread?
 

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Another question; for the guys running multiple sources (high-outputs from OE HU, optical and HEC BT), I know the Helix's have auto-sense turn on from high-level inputs, but if you're going to use optical and BT inputs without turning the OE HU on, does a REM turn-on line need to be used?
 

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Thanks for the information! Doug also mentioned to me that digital sources are often lower db. I'm new to using a digital source and still learning.

I'm currently using a Filo x5 line out directly to the Helix RCA input. This is temporary until I install a coax to optical converter.

I have a mixture of 320 MP3's and 24 bit FLAC. What is the best method to properly set the input gain?
Set the outputs to match the analogue output (whichh will have been clean due to scoping it) so you get full volume by both inputs
 

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Just to confirm, the gain adjustments on the side of the Helix (P Six) are just to adjust input gain for channels A-F, not the optical input or HEC BT inputs, correct?
 
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