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Discussion Starter #1
I tried the out the optical input on the Helix yesterday and it sounds great. I know a digital signal does not clip so I"m wondering about the input gain on the Helix. Is there any reason I can't max the input gain at +10db since it's a digital signal?

If not, what is the proper way to set the digital input gain?
 

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I don't know if it is OK to "max" the input gain to +10dB (it probably is), but I personally boost it by 8.5dB on my current setup. The US distributor for Audiotech Fischer also told me that he too boosts his by about 8dB. Without the boost, the digital signal from my AmpPro 4 device results in significantly lower volume levels than when using the analog outputs of the AmpPro (which is why I boosted mine - to bring it up to about the same volume level as analog).
 

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Discussion Starter #3
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?
 

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Yeah, good question about why there is even a setting for digital - not really sure. Might just be something that they had in place already for analog and it just "carried over" to digital? I'm one of those people that try to never set anything to the maximum if possible, in fear that it leaves no "headroom" - which is probably why I left mine at 8.5dB, which gives me plenty of volume and still leaves a little "headroom". No idea if leaving some "headroom" is beneficial in this case, but I really didn't need any more volume, so I didn't put it. :)
 

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Discussion Starter #5
I only tried it becasue it allows me to lower the amp gains a little more. If I run the amp gains too high I get shitty noise at low volume. I agree that usually maxing a setting is not ideal but regarding a digital signal I think its irrelevant.

Hopefully someone chimes in that knows the answer....
 

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Discussion Starter #6
Yeah, good question about why there is even a setting for digital - not really sure. Might just be something that they had in place already for analog and it just "carried over" to digital? I'm one of those people that try to never set anything to the maximum if possible, in fear that it leaves no "headroom" - which is probably why I left mine at 8.5dB, which gives me plenty of volume and still leaves a little "headroom". No idea if leaving some "headroom" is beneficial in this case, but I really didn't need any more volume, so I didn't put it. :)
I am also curious how you are controlling volume. I'm using a URC.3 and the only way I can get it to work is using one knob for master volume and the other for digital volume. I tried turning the master volume off and lost sound. Just seems strange because both knobs still control the volume, lol.
 

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I am also curious how you are controlling volume. I'm using a URC.3 and the only way I can get it to work is using one knob for master volume and the other for digital volume. I tried turning the master volume off and lost sound. Just seems strange because both knobs still control the volume, lol.
While I do have a URC-2, I've never connected it yet... I just control all volume from my head-unit (2018 Dodge Challenger OEM head-unit, going through a PAC AmpPro 4). I really don't even need the URC.2 - I would mainly use it for tune switching quickly and easily (like between a one-seat tune to a two-seat tune).
 

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Discussion Starter #8
Ahhh... I'm using a factory HU unit for volume control on anything analog. Digital I'm streaming from a S9+ phone, completely bypassing the HU. Wish there was a way to use the HU for volume and to skip tracks.
 

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Yeah, I'm not going straight to the DSP for anything - everything goes through the headunit. I love good-sounding audio, but I'm not willing to lose easy control of my music through my OEM 8.4" touchscreen head-unit. I mostly listen to 320k .mp3 and .flac files that are stored on a 128gb "stubby" USB thumbdrive that is connected to a USB port in my console (I listen mostly to "local" music). I also stream via Tidal at times.
 

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Discussion Starter #10
I also have a USB drive but it won't read lossless (G37 factory Bose/NAV system). I'm considering loading up MP3 320K just for normal listening. If I'm in the mood to crank it up I can switch over to digital and stream FLAC or Tidal straight to the DSP.
 

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Is this where you do this?

View attachment 270991
Well, it depends... :)

The Helix is strange in that if you use the optical input connection, you can use either the "Main Routing" or the "Digital Routing" IO tab. If you are using the "Main Routing" tab, then you would adjust the gain next to the word "Analog". If you use the "Digital Routing" tab, then you would adjust the gain setting next to the word "Digital".

It's kind of confusing how that works if you only use a single input (like me), since you can actually use either the "Main Routing" IO tab or the "Digital Routing" IO tab for the optical connection, but just adjust the gain value next to whatever I/O tab you are using.

Hope that makes sense.
 

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So if I drag and drop the Digital L and R channels into the "Main Routing", then I use the gain up top next to the word "Analog"? If I use the "Digital Routing" tab and drag and drop my Digital L and R channels, I use the gain next to "Digital"? Makes sense. Well, no it doesn't, but I think I get it...😁

What are you using for digital signal setup? Default is -57dB and 1s.
 

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So if I drag and drop the Digital L and R channels into the "Main Routing", then I use the gain up top next to the word "Analog"? If I use the "Digital Routing" tab and drag and drop my Digital L and R channels, I use the gain next to "Digital"? Makes sense. Well, no it doesn't, but I think I get it...
Yes, exactly!

What are you using for digital signal setup? Default is -57dB and 1s.
Not following on this one... :) I personally use the "Digital Routing" tab and +8.5dB for the "Digitial" gain setting.

Not sure what you mean by "Default is -57dB and 1s".

For the record, I use the DSP.3 - so not a Helix amp/DSP combo unit.
 

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Discussion Starter #17
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?
 

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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?
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)...
 

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Discussion Starter #19
Ahhh... havent messed with the app yet, that's probably it... thanks!! I have a DSP.3
 

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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?
 
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