Helix DSP Mini - optical vs line in

Will be using my iPhone as the source with a Topping D10 usb DAC.

This means I can use either the optical or line in on the Helix.

Catch is that the optical only does up to 96kHz so I either have to set the bit rate in a player app or just store lower bit rate music.

Or I can use the line out of the D10 at full bit rate.

Will there be any noticeable difference in the two input options?

Unfortunately I cannot test as it’s all in storage.

Source material is hi res audio from HDTracks and Amazon Music HD (although not seen much over 48KHz on there!)


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Optical is way better than analogue into a helix... more detail, higher soundstage and better low end vs the analogue in the exact same setup with my iPhone XR, plug both in and back to back it level matched by switching between the two... in my setup the difference was obvious... tonny came to the same conclusion, as did dan Kirton the Emma judge if you know him, I didn’t tell him which was which or what was different, I just swapped back and forth and let him tell me the differences between two settings

im just about to build an iPad mini 5 into my dash in the next week or two :)

That is what I suspected :)

Even at the limited bit rate via optical it should be better due to the DAC in the Helix.

When I get around to installing it I’ll check as well :)


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Originally Posted by SiW80

That is what I suspected :)

Even at the limited bit rate via optical it should be better due to the DAC in the Helix.

When I get around to installing it I’ll check as well :)


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nige (team dls nige) actually has just put one in, and says optical actually outperforms coax into his dsp pro 2...

most of the high-res music you can buy/stream is 96k/24bit, so optical's fine for this. i've used the onkyo app on ios, just set upsampling to on or off. i've had 48k cause clicks. depends on the material.

d10 does dsd only analog-output, so you'll need to pre-transcode dsd to pcm or transcode it on the fly to pcm. (but dsd is largely a waste of space/time imo)

high-res stuff is a mess of incompatible standards the complexity wasn't worth it for me.

blew the dust off my d10, plugged toslink into the ps8pro dsp. iphone -> ck usb3 -> d10 -> toslink -> dsp. volume control in the psc/dsp.

the onkyo app did just fine for 96k content. some of the 192k content, silence. the various upsampling modes wouldn't change anything, but you gotta force-close the app for these setting changes to get picked up. there's no downsampling modes.

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Originally Posted by nadams5755

blew the dust off my d10, plugged toslink into the ps8pro dsp. iphone -> ck usb3 -> d10 -> toslink -> dsp. volume control in the psc/dsp.

the onkyo app did just fine for 96k content. some of the 192k content, silence. the various upsampling modes wouldn't change anything, but you gotta force-close the app for these setting changes to get picked up. there's no downsampling modes.

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I had the same with the Helix Mini.

Shame more apps won’t let you choose the output. Everplay and Vox are the only apps on iOS I have found to do this.


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I'm integrating some Alpine amplifiers and subwoofer box into my 2014 Ford F150 with a Sony amplified system, and will be using a PAC AmpPRO interface to get low-level (and optical) outputs that will go to my HELIX DSP Mini. I'd like to use BOTH the Optical AND the RCA inputs for the HELIX DSP Mini.
My question is: Will the HELIX DSP Mini allow me to use both the Optical and RCA signals at the same time?
I have an amp rack that I want to wire up, but need to know this before moving forward.

Yes it does :) I believe it can be set to auto switch between inputs (signal sensing) in the pc-tool software, but the most convenient method is to use one of the wired remote controllers (urc.3/director/conductor) to manually switch between inputs.

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Originally Posted by Haakono

Yes it does :) I believe it can be set to auto switch between inputs (signal sensing) in the pc-tool software, but the most convenient method is to use one of the wired remote controllers (urc.3/director/conductor) to manually switch between inputs.

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As the pac amp pro will output both at the same time auto switching won’t work, so it would need a urc.3 at least to be able to switch between the two inputs

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Originally Posted by dumdum

As the pac amp pro will output both at the same time auto switching won’t work, so it would need a urc.3 at least to be able to switch between the two inputs

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Yes, you're right. Yesterday I was able to check with manufacturer via their website and found only the plug-in controllers will switch between various inputs.
They seemed to indicate that having L & R optical would allow all outputs of the DSP Mini to work normally.
Thanks.

I've set up the DSP to receive an optical signal from the AmpPRO, so it should work that way. If I have any issues, I'll also run low level RCA cables from the AmpPro to the ampRack.

I picked up the urc.3 wired controller off of eBay. I really want the conductor, but it's price is super inflated right now.

What prices have you been quoted for a conductor?

Actual distributors of Helix have prices of 30-40% higher than non-official distributors (ebay). On ebay the lowest price I've seen is $249 w/free shipping.
Compare that to $70 for the urc.3 that I just purchased - coming from the Great Britain.

I finally got a URC3 and it’s so much easier than the wifi via app to control volume.

Just watch as there is no maximum volume level anymore and if you go into the wifi option in PC tools it cancels your URC3 settings. I found out the hard way but luckily turned the input volume down just in time.


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The WiFi controller is an add on module, right? When I start using the UCR.3 (once it arrives), will I have volume run-away issues with it?? I don't want to blow my tweeters, because they're hooked up directly to the DSP (active crossover).

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Originally Posted by TechUser

The WiFi controller is an add on module, right? When I start using the UCR.3 (once it arrives), will I have volume run-away issues with it?? I don't want to blow my tweeters, because they're hooked up directly to the DSP (active crossover).

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No you won't.

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Originally Posted by TechUser

The WiFi controller is an add on module, right? When I start using the UCR.3 (once it arrives), will I have volume run-away issues with it?? I don't want to blow my tweeters, because they're hooked up directly to the DSP (active crossover).

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Tbh I don’t know what the above poster means about no volume limit… it does, it’s the pot all the way to the right, Setup is no different to a director or conductor in that respect

Ok, thanks. I've never installed a DSP before, so I'm glad I have your input.

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Originally Posted by TechUser

Ok, thanks. I've never installed a DSP before, so I'm glad I have your input.

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Any questions drop me a message, no matter how daft they seem

So, I've finally got some time testing my system now that it's in my truck. I'm using a relay to turn on all amp trigger lines, and it turns on all amplifiers on power up, and I'm getting low sound volume out of the rear speakers, but after about approx 20 seconds the DSP turns off all Amp trigger lines. After a lot of reading in my Helix manual and this forum, I went back to the screen shots I took of setting up the DSP on my bench. What I found was I put it on PowerSave mode with a 30 second time out before it turns off all the amplifiers. So now I have to connect it to a laptop pc to adjust it much longer, or turn off PowerSave completely.

I have an old PC laptop (Win XP) and my daughters MacBook Pro- both are a no go. It looks like I'll have to bring my Nuc PC desktop setup into the back seat of my truck to get the job done. I wish there was a Chrome or Apple version of the DSP app.

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Originally Posted by TechUser

So, I've finally got some time testing my system now that it's in my truck. I'm using a relay to turn on all amp trigger lines, and it turns on all amplifiers on power up, and I'm getting low sound volume out of the rear speakers, but after about approx 20 seconds the DSP turns off all Amp trigger lines. After a lot of reading in my Helix manual and this forum, I went back to the screen shots I took of setting up the DSP on my bench. What I found was I put it on PowerSave mode with a 30 second time out before it turns off all the amplifiers. So now I have to connect it to a laptop pc to adjust it much longer, or turn off PowerSave completely.

I have an old PC laptop (Win XP) and my daughters MacBook Pro- both are a no go. It looks like I'll have to bring my Nuc PC desktop setup into the back seat of my truck to get the job done. I wish there was a Chrome or Apple version of the DSP app.

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Buy a version of win 7 and put it on the xp laptop, I bought win 10 license from somewhere in South America for £16 ($22 ish) then use the laptop, if it’s on win xp you clearly don’t run much modern stuff on it (win 7 normally runs fine on win xp laptops, I wouldn’t go to win 10 though just for it being resource heavy

there are apps for Apple, but not a full tuning app as it would be way too resource heavy and look awful stacked up with a 30 band eq in each channel, it’s just not practical… plus the helix software for the pc is very well laid out and simple to use

i turn power save off if I’m honest, but as long as you’re playing music power save won’t turn anything off

also using a relay isn’t necessary unless you’re turning on ten amps or more, or adding extras like fans off the relay, the relay can also induce switching noise in a system

Still having same problem, goes into power save. I'm going to try bypassing the relay, and go straight to the 3 amplifiers. And thanks for the XP tip on Win7. I will definitely try it. I run nothing else on that old laptop, except a few random apps.

The thing is, the amps are turning on fine with the relay. But it might be a DSP timing thing...

The relay won’t stop it working correctly, but try removing it, your current draw for three amps is fine direct

sounds like a good candidate for a win 7 upgrade

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Originally Posted by dumdum

The relay won’t stop it working correctly, but try removing it, your current draw for three amps is fine direct

sounds like a good candidate for a win 7 upgrade

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The relay circuit is gone, and I'm now running the turn-on signal direct from the Helix DSP Mini's "Trigger Output" line to the three Alpine amplifiers. No change. The trigger output goes 'low' after the time-out on power save mode. This means the DSP doesn't recognize the input signal coming in from the AmpPro.

I'm getting the audio signal and amplifier trigger line from the F150 OEM head unit using AmpPro.
It feeds low level RCA and/or digital optical signal to the DSP unit. I'm feeding the DSP both RCA and Optical, so I have an option if I have an issue with one, I can troubleshoot using the other.
The DSP feeds the following speakers:

-Front Left Tweeter
-Front Right Tweeter
-Front Left Mid Woofer
-Front Right Mid Woofer
-Front Center Mid

The Rear speakers are NOT fed through the DSP. They get their signals from the AmpPro's rear left and right RCA lines.

The funny thing is, all three amplifiers are turn 'on' and light up. The rear speakers work, so I know the AmpPro is sending low level signals to the amp that drives the rear speakers, but the DSP is acting like there's no signal coming into it (no front soundstage), so it goes into power-save mode.

I've created both Analog and Digital optical inputs on the IO section - analog inputs on the Main Routing page, and digital inputs on the digital routing tab.
HEC/AUX routing is off
FX functions are turned off for now.
I've tried turning off power-save mode, but it leaves amps on and still doesn't provide an output signals out of the DSP.

Should I try running the system without the URC.3 wired controller?
I'm going to look for a step by step walk through...

What are you using for your turn on wire for the minidsp?

Also it would probably help to have some screenshots of your settings for the minidsp.
a

I'll try to post some tomorrow. The DSP is triggered by the AmpPro which has a 16 gauge trigger output line that goes to +12V when Ford OEM system turns on.

What priority are the inputs set as? Could be the order the DSP takes the inputs and it doesn’t see anything so turns off.

Also check the sensitivity and threshold settings of the inputs.

What is the turn off time delay set at on the DSP?

Does the DSP turn off or just the amps?


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yeah, check (disable?) the power-savings settings.

Thank you for all your feedback. It made me look further up the signal stream at the source - the AmpPRO.

Apparently I hadn't set up the minimum volume level on the unit using the supplied volume knob - I thought that was only for chime volume level. Once I turned it (the input signal) up, the Helix recognized the input signal and woke up - and never went into power save mode. The UCR.3 works as well. I still haven't tested if the optical signal works or not. I think I can just turn off the analog input and run with digital only, and that's how I could tell if it was working. The optical connection at the AmpPRO (near the HU) is not very tight, but the connector is snug on the Helix DSP's end.

Now you just need to make the drive to phoenix for a tune session ;)

Yeah, that’s a whole different conversation. I think it would still be a benefit to for me to add screenshots of the DSP screens to troubleshoot other minor issues. Do you own an RTA Mic out there in AZ?

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Originally Posted by TechUser

Yeah, that’s a whole different conversation. I think it would still be a benefit to for me to add screenshots of the DSP screens to troubleshoot other minor issues. Do you own an RTA Mic out there in AZ?

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I have a few of them and some run smaart and rew. Justin Zazzi and I like teaching others how to tune

Yes, I've installed a UCR.3 into my cab, and I'm running both signals, however I've set the DSP to accept only the optical at this point. I've sound dampened my doors and rear cab wall and the sound from my stock Sony (OEM) speakers is very good. Just recently I've installed Morel component speakers in the A-pillars and front doors and it sounds even better. I use the UCR.3 button to switch between driver and passenger for a time aligned front soundstage. There's still more I can get out of the system, but I'm too busy right now.