As Doug mentioned, it applies the sub processing on all of the subwoofer channels.
I have an underseat sub behind the passenger seat to fill in bass in the driving position where it's getting nulled in my car (2 seater roadster, "subs" are only inches away from the back of the seats in the rear panel). It works surprisingly well at evening out the bass in the cabin. I tried several different subs in the trunk but the underseat beat them all at the task. I just used one Helix channel and an rca splitter. Sum the left and right to the one output.
https://www.amazon.com/gp/product/B007HVDCWI/
If you aren't going to use the 8th channel in the Helix for something else, there is no reason to buy a y-adapter. Just have Helix output sub on 2 channels as Skizer mentioned.
I always set sub up as a single channel and use a Y. It avoids any chance of setting the two sub channels differently or causing any confusion.
Doug Dobson
Also, it seems that at least the DSP.3 does NOT do it's augmented bass processing on all channels labeled as a subwoofer. The manual clearly states that it only does the processing on channel H - it seems that it's "hardcoded" on the DSP.3 for channel H. So if you use G & H, you'd only get processing on half of the sub output. So a y-adapter seems the only way to get full augmented bass processing on the DSP.3. At least that is my understanding... It seems that the "labels" in the Helix are not actually used for anything other than to help you keep track of what channel is what - the software doesn't actually use the labels to make any decisions in regards to augmented bass processing.
If you don't use augmented bass processing, then you can use two DSP output channels for a single sub just fine (it works fine for me using the "Subwoofer L" and "Subwoofer R" labels with channels G & H - but I don't currently use augmented bass processing. I can actually hear the sub output double when I unmute the second subwoofer channel, so I know it's working fine with the "Subwoofer L" and "Subwoofer R" labels on channels G & H. If I wanted to use augmented bass processing, I would need to use channel H only with a y-adpater at my under-seat sub.
Again, that it my understanding after looking into this (manual, Doug, etc). Doug -please correct me if I got that wrong... After all, I've only been using the Helix DSP.3 for a very short time, so I am *certainly* no expert! :-)
Last edited by jtrosky; 12-04-2019 at 12:02 PM.
It is the safest bet for sure. There seems to be confusion about how the features apply to different processors, and with different software, but the labeled channels always work as designed from my testing.
Doug Dobson
I'll make sure to take some actual measurements of the augmented bass processing results when using two DSP output channels (both labeled as a Subwoofer) and when using a single DSP output channel and a y-adapter on the DSP.3. That should tell us for sure whether or not the augmented bass processing works only on channel H or if it works on any channel labeled as a subwoofer - at least on the DSP.3 with the latest software. It sounds like the results may be different depending on the exact software version and/or the exact DSP model. Since this thread is specific to the DSP.3, it should be helpful for those with a DSP.3 going forward.
Although, then again, I'm not sure if the results would even be visible when playing pink noise at a certain volume level. If I understand the augmented bass processing correctly, it basically increases the subwoofer output at lower volumes (not at higher volumes) - so it may not even be measurable with "loud" pink noise. I'll see what I can figure out though and post results.
I can only speak for my experiments, but when I set up my install with the two stock subs routed to Subwoofer 1 and 2 (E & F), and the underseat to subwoofer 3 (, the sub level worked on all three speakers, and when I tried switching the effect in and out with only the two stock subs (on channels E and F), it was noticeably switching on and off. Same goes for having the center on a different channel than the software states (G) - it applied the center effect accordingly.
Thanks for the input - and you may be 100% correct. I'm just going by what it says in the DSP.3 manual, which may just be outdated or incorrect. I just thought that it was really specific as to how it works, so I assumed it was accurate. Here is what it says in the DSP.3 manual about Augmented Bass Processing :
I do have another, completely un-related gain-related question...
My head-unit is connected to the DSP.3 via the Optical input (via AmpPro4 Optical output). I *never* see *any* colors in the background of the "Channel Gain & Output Level" slider in the Helix software. The background is black no matter what volume level I have my head-unit at or what I'm playing (tones, music, etc). It seems like even at very high volumes, the highest the dB level shown next to the slider is -30dB or lower. I always thought it was strange that my amp gains needed to be set the same as they were with my 4v pre-out DSR1 (since the DSP.3 has 6v pre-outs). So.... I'm wondering if I would be better off boosting the input gain of the optical input (via the IO menu) so that I can then lower my amp gains. While I don't have a significant noise floor now, I just figured that lower amp gain is better - so why not boost the digital input signal and lower the amp "Analog" gains.... Especially since the DSP.3 channel output levels never seem to get anywhere near 0dB now.... I'm new to this digital stuff, but to me, boosting a digital input signal wouldn't add any noise, whereas boosting an analog signal on the amps does add noise.
Thoughts? Does anyone else have the issue where they never see any colored backgrounds on the CHannel Gain & Output Level? Or is that simply because the output levels never get high enough to "trigger" the colored backgrounds?
Thank you!
Boost it , if you can ! If U don't like results , unboost it .
What have you got to lose ? YOLO
The noise that enters a beam of light is Zero/zilch/none. Now magnetically induced noise in a wire made of copper , 'Skys the Limit' !
Last edited by Queef; 12-06-2019 at 07:22 AM.