Helix DSP.3 help thread

[dobslob]

So I don't have to worry about "overdriving" the amp inputs from the Helix outputs at all?? I mean if an amp (or my under-seat sub, for example) is only capable of 2V on the inputs, I don't have to worry about the Helix sending up to 6V to those inputs from the Helix (max, obviously, but still possible, right)? If I truly don't need to worry about it, then that is great - I just want to be sure - I just don't want to damage my amp, my under-sear sub or my speakers if I can avoid it. :-)

Also - I'm curious - do most people use 0db sine waves for gain setting or -5dB? Keep in mind that I only have 75W RMS per channel, so I just want to make the best use of it as I tend to like loud music.

I'm also kind of curious about the head-unit "max" volume. I have a feeling my stock head-unit can go over 75% volume before clipping, but I'd like to confirm that. Is the o-scope the best way to determine that (check DSP outputs for clipping with o-scope)? Again, just trying to get the most from my setup...

Thanks.

You stock head won't clip with the Amp Pro.

0dB tracks are used up to the amplifier stage, then its a do whatever you want to need. Many shops use -5dB for kids and highs and -10dB on subs, others will do -10 and -15dB. This id for your own system so you don't need to play it as safe.

Just read about the different sub amp input range, you may need to reduce the output in the DSP, but again that is just a safety. Play a 40Hz tone and see what happens. Soft clipping at -10dB is likely fine. You won't hear it and it won't be enough to damage your subs unless you are cranking test tones.

[dobslob]

In the DSP.3 IO matrix config, there are three matrices - "Main Routing", "HEX/Aux Routing" and "Digital Routing".

In my case, since I'm only ever going to use the optical digital input on the Helix, is there any advantage to assigning my "Digital In L" and "Digital In R" inputs directly in the "Main Routing" matrix instead of in the "Digital Routing" matrix, like I have it now? I wonder if the audio output would start any faster that way (thinking out loud). Right now, it takes a few seconds after my head-unit starts playing before I get any audio - maybe the audio output will be faster if I defined the digital inputs in the "Main Routing" matrix?

Not a big deal at all (I'm only talking about a few second delay before audio starts), but was just curious if maybe using the "Main Routing" matrix for the digital inputs would be a better option in my case.

You can use the digital in as main or just make sure to turn off automatic switching via signal detection. That will cause longer delays. There is a slight delay to the processing so it will never fire up immediately.

[Babs]

If you hit "stop measurement" it will freeze the white RTA line, you can then also hit "stop analyzer" if you want the red line to stop moving around too. You can resize the RTA window to suit, as well as move it around. If it defaults to full screen, just double click the top bar/title bar and it should go to resizable mode. It will remain over the top, so you can resize it and move it to a point that lets you see it and work on the EQ at the same time.

You can also take a snapshot by right clicking one of the memory buttons along the top.

You can also hit the Set EQ button, which will set the required EQs for you if you want to copy the RTA curve preciseley.

It's also worth giving the Auto EQ option a try - similar to the Set EQ function, but continuously takes measurements and makes adjustments to the selected channels automatically until it nails the curve. Skizer has posted a video about it, and how to use it which I found really helpful: https://www.caraudiojunkies.com/show...kies-Exclusive

Yep thanks I kinda figured it out. I’ll size it so I can pick channels above the RTA menu on main screen, and EQ below it. Then if I need to make it go away simply close the window. When I hit RTA again it would maintain that size and location thankfully. It’s been my go-to measuring tool for a good while now. The memory save feature is a truly nice thing now as well. Jazzi's spreadsheet tool for outputting target curve text files with crossovers applied is a great great thing.. I've input those manually into the Helix RTA as custom targets to work with so I can EQ individual drivers including their respective LR4 crossover slopes.

This was roughly an hour and a half, EQ'ing each driver, summing a flat response down sides, then repeating on the other side. TA was mostly by distance with some ear work as well. Here's the whole system:



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[jtrosky]

You won't get any clipping of signal on the DSP.3 as long as you didn't unblock the Digital Clipping Protection box in the DCM menu. It limits the output from being overdriven. In the main screen of the Helix software you can see when the output is getting close to maximim output behind the "Channel Gain & Output Level" slider. Keeping the DSP out of the red except for extreme peaks is the key.

I'm not sure what to do with the JL amplifiers. I'd think that you would be fine on low with minimum sensitivity, but I have't played much with them. The output of the DSP.3 is said to be 6v but I have measured 7v and more on certain tracks. You would need to test the outputs of the JL to know for sure what it will do.

You stock head won't clip with the Amp Pro.

Just read about the different sub amp input range, you may need to reduce the output in the DSP, but again that is just a safety. Play a 40Hz tone and see what happens. Soft clipping at -10dB is likely fine. You won't hear it and it won't be enough to damage your subs unless you are cranking test tones.

Ok - just to make sure I understand this all... I'm very new to the digital audio connections, especially in the car - so is it not possible for the head-unit outputs to clip when connected to the DSP.3 via the AmpPro4 optical connection? Since it's digital, there is no physical input sensitivity control knobs or anything, so does that mean that there is no possibility of clipping with a digital connection between head-unit and DSP.3? Sorry if that is a stupid question. :-)

For some reason, I'm not seeing those colored bars behind the "Channel Gain & Output Level" slider in the Helix windows software. I see the input dB number going up and down, but no colored background (it's just black all of the time)? I'll have to look at that more closely to see why that isn't happening - maybe I just didn't turn the volume up high enough for the colored bars to show at all?

Even with the 6v outputs on the DSP.3, I still have to turn my JL Audio amp gains up to like 10 or 11 o'clock, even on the "Low" input sensitivity setting, which I thought was strange. Basically, the amp gains are set to the same spot as they were with the Rockford DSR-1, which has 4v outputs. I would have just thought that the gains would need to be lower with the DSP.3. I'm going to connect my o-scope to the amp speaker outputs and see what the signal actually looks like to make sure I'm not clipping at the amp speaker outputs.

Any recommendation as to what volume level to use on the Dodge 8.4 head-unit when setting gains? That is something that I've never really fully understood. Some say to set it at 75% volume, some 80% and some say to check the head-unit outputs to see where it starts clipping, but since it's a digital connection, I have no way to see that.

In a nutshell, I just want to make sure that I don't damage any of my speakers or under-seat sub - especially when I go to tune, which is where I will be playing pink noise at relatively high volumes... Since I'm new to this, I would just rather be safe than sorry. :-)

You can use the digital in as main or just make sure to turn off automatic switching via signal detection. That will cause longer delays. There is a slight delay to the processing so it will never fire up immediately.

Ok, thank you. Are there any particular advantages or disadvantages of using the Main matrix for the digital connections (vs using the Optical matrix)? Or doesn't it really matter as long as you have the automatic switching settings set up correctly?

THANK YOU for taking the time to help me understand some of this stuff! I was pretty comfortable with the DSR-1 setup, but the Helix is a more expensive and more powerful piece of equipment - and I just want to have a better understanding of things - especially since I also went from an analog connection to a digital connection, which changes things quite a bit. :-)

Have a nice Thanksgiving! :-)

[jtrosky]

Oh - on a good note... So far, I have just set rough crossovers (electrical only), rough TA and a few minor level changes (lowering drivers side dash speaker by 2dB and rear-deck fill speakers a little) and bumping up the bass and treble a little with the head-unit bass/mid/treble controls and this thing already sounds great - without even taking a single measurement or doing any real EQ on the DSP.3 yet! Hope to get a full tune done today or tomorrow - but I'm already having better results than I did with my Rockford DSR-1 - even after playing with that thing for months. :-)

Helix is the real deal when it comes to clean, powerful audio processing!! :-)

[Babs]

Oh - on a good note... So far, I have just set rough crossovers (electrical only), rough TA and a few minor level changes (lowering drivers side dash speaker by 2dB and rear-deck fill speakers a little) and bumping up the bass and treble a little with the head-unit bass/mid/treble controls and this thing already sounds great - without even taking a single measurement or doing any real EQ on the DSP.3 yet! Hope to get a full tune done today or tomorrow - but I'm already having better results than I did with my Rockford DSR-1 - even after playing with that thing for months. :-)

Helix is the real deal when it comes to clean, powerful audio processing!! :-)

Yep it’s all about getting good with the software and understanding the process. A tape measure, laptop and a UMIK-1 and the Helix tool and a car can be tuned in an hour or two.


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[jtrosky]

For what it's worth, as I learn to use the software in-car, I've found that using the 1-8 number keys to toggle channel muting very nice! Makes per-channel measurements quick and easy (instead of using the laptop trackpad to mute/unmute the channels). It's the little things... :-)

[jtrosky]

Another Helix IO question... In the IO setup, you can use "Subwoofer1" (through Subwoofer4) for you sub, but they also have a "Subwoofer L" and "Subwoofer R", which isn't mentioned anywhere in the docs.

Since my under-seat sub has two RCA jacks (L and R) and I have a standard stereo RCA cable run from the DSP to the sub, I'm assuming I should route "Digital L" (100%) to "Subwoofer L" and "Digital R" (100%) to "Subwoofer R", like this:


Would you agree?


The other option would be this:


Just want to make sure which way is "correct" - if there is any difference at all. I haven't measured both options yet to see if there is a difference. Will try today, but just wanted to see what others thought.

Thank you - Happy Thanksgiving! :-)

[SkizeR]

set both as subwoofer 1, then sum left and right digital inputs to that output

[jtrosky]

set both as subwoofer 1, then sum left and right digital inputs to that output

Thanks.

So you're saying to do it like this:


instead of like this (which is how I have it now):


Doesn't that end up doing the same thing in the end?

Although, I also noticed that the Helix DSP.3 manual says that it only processes the subwoofer FX stuff on Channel H. So if I want to use those Helix effects, I may just have to use a 2-to-1 RCA adapter and use a single Helix channel for the sub, instead of using 2 channels like I am now... Not sure about that - Doug mentioned above that it processes the sub FX stuff on all channels labeled as a subwoofer, but the manual says it only does it on channel H - so not sure which is correct yet. Will have to do some testing...

So far, I absolutely love the Helix. Did some VERY basic manual EQ (very few filters) and have been jamming to some old school Black Sabbath and it sounds so damn good.... :-)