Eric_Harbauer Posted May 4, 2017 Share Posted May 4, 2017 UPDATED AND CORRECTED!!!My apoligies for the incorrect numbers (I read the timescale incorrectly on my Oscope screen) In the original post. I'd like to begin by saying I've been very impressed with my helix so far. I'm really enjoying it, and I am not posting this to bash it in any way whatsoever. But I'm naturally curious, and mostly unhappy with the SPDIF I/O, and wanted to really understand why, which is what prompted this whole experiment. With all the connection possibilities I have been experimenting hooking different pieces of gear I own to the various I/Os, with some great, and some not so great results. One of the biggest questions I've had has been with the digital I/Os. Is it actually faster to use SPDIF? Logic would say yes. No A/D conversion. It has to be faster right? Well I haven't been so happy with Helix in that regard. My 2 notes torpedo Hasn't sounded as good as I think it should through the SPDIF I/O. So I started digging online. What I found was a lot of nonsense. Threads saying that each foot of cable added 1ms of latency (this is wrong by the way) and people claiming that Helix is sub 1ms latency. hmmm Just a few quick numbers, as tested on my Helix floor with an O scope straight thru on a blank preset. Each and every time you convert A/D -> D/A it's 1.8 ms ...Yes that means each loop you engage adds 1.8 ms So to be clear. guitar in + 4 loops (in series) + 1/4" out = 9ms maximum of latency due to A/d conversion 4 cable method should clock in at around 3.6ms (assuming no other effects in circuit) SPIDIF I/O appears to not run as fast as as the standard I/Os 48k runs slightly faster then 44.1k 88k or 96k I tested this by looping spdif send and return to itself. As you add gear latency will increase due to the outboard gear. Other interesting notes about the SPDIF I/O there is no option for sync (internal vs spdif) and it connects to my two notes torpedo and transmits and receives audio even when the two units are set to entirely different sync and sample rate settings. There's also other spdif weirdness but as I said it's not my intent to bash Helix, so I won't go into them here. On the positive side, adding blocks does not appear to slow the unit down much. like less than .2ms for an amp. I haven't thoroughly tested this but a real quick check loading blocks up till I started to run out of DSP and very little change in latency. IR Blocks may have more latency associated with them but that is probably more due to the nature of what an IR actually is rather than processing power My takeaways. Use the internal blocks in helix as much as possible. Minimize A/D conversion. Stereo loops (parallel) are 1.8ms for both Serial loops are 1.8ms each Avoid using SPDIF for live playing (it's fine for re-amping etc) Anyway... I thought I'd share this. Rock On âœŒ Quote Link to comment Share on other sites More sharing options...
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