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Runs out of steam (dsp) pretty quick


unclejambo
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Had a bit of fun with the Helix last night. I think the routing architecture is genius but found most of the amp sims pretty awful sounding in all honesty. Anyhow, I landed on a dual amp combination of the fender twin and svt models that I really liked. I was pretty disappointed that doing so greyed out a lot  of the other modules, presumably due to lacking dsp. It was late and I didn't get too deep before bedtime, so maybe deleting the modules I won't be using will free up a load of dsp.

I've not tried sending and returning to my actual stomp boxes yet but my main reason for buying the helix is as a switching system for my external pedals, using eq modules to push those stompboxes, and to run dual amp sims (to one output) and use the remaining 2 paths to process a microphone in and a synth sub-mix on aux in. I gather those remaining two paths utilize separate dsp, so I'm just hoping I can cut the fat and use the first two as I'd hoped.

I'll experiment some more but I was just really surprised that my first attempt at building a patch exhausted it's resources. I come from a live-sound engineer background where most digital desks dsp are spec'd so that you're hard pressed to max them out. I'm surprised the helix wasn't built the same way.

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.... but found most of the amp sims pretty awful sounding in all honesty. ...

 

That surprises me a bit. Perhaps you need more time and experimentation. What are you routing the outputs to? That needs to be considered so you can properly match amp/preamp/mic/cab selections to your external amp/monitors.

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I come from a live-sound engineer background where most digital desks dsp are spec'd so that you're hard pressed to max them out. I'm surprised the helix wasn't built the same way.

 

Okay, I'm gonna finish my Dynamic DSP blog this week if it kills me.

 

Helix is not underpowered. The design alternative is to artificially restrict the number of amps and simultaneous effects to fool you into thinking your box can take anything you throw at it. Just like your digital desks artificially restrict the number of channels, auxes, busses, and effects to fool you into thinking it's maxed out, when it likely may have 20-60% of its DSP sitting there, wasted, depending on what's actually running at the time.

 

Check out presets like 1 FACTORY 1 > 17D, 20D (three amps!), 21B, and 27D. Also try spanning your Amp+Cab blocks across both DSPs, as in 8 TEMPLATES > 01B Parallel Spans.

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Don't you basically want to try to get one amp in each signal path (1 and 2) so that one processor handles one amp/cab and the 2nd one handles the second amp/cab when using two amp/cab models in a preset?  Maybe have front of amp effects in path 1 with the 1st amp, then pass that into amp 2 with the post amp effects in path 2?

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You need to play with mic/speaker combos to get the best sound out of the amp sims.

 

As far as DSP, you need to read up on it some more, I have presets with multiple amps several stereo delays, multiple effects and still have room for more.

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I'm running (or plan on running) some effects before the split (affects both amps) and some after and then feeding the output of both head sims into a single cab sim. So yes, in this instance, I'm only utilizing a single path... I still hoped that I'd be able to throw a hell of a lot more at each of those paths. 

I'd typically want to use path 2 for an aux in or mic. I'm yet to get that far.

As I'm using amp and cab sims, I'm monitoring through a hifi and some decent floor standing speakers. They're detailed, go pretty low, my room is pretty dry and I've mixed on them in the past so I trust them to give me a pretty accurate representation of how things sound. I've also listened via the headphone out on triple driver, moulded iems, which again, I've used for pretty critical listening in the past.

I killed all surplus modules (my initial tinkering was based around swapping modules out on an existing preset) and it allowed me to add some distortion modules at least.. I'll be switching those module outs for routing to outboard stompboxes when I get a little more time too so maybe that'll free some stuff up.

The one module I have left is a reverb after the cab sim as even the best amp/cab sims on there sound digital to my ears without it. Perhaps this module is a dsp hog and I can get creative with the cab sim settings to achieve a little more realism... will continue to play around.

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I don't use dual amps, but I think I could with my workflow.

I split path 1, use 1A for my acoustic guitar signal, directly out

 

I use path 1B for the amp (but not the cab) and some gain/comp/eq things.

Then I have GOBS of processing I use on 2A for the electric. I could add another amp on 2B but I add a couple big verbs for special FX I switch between.

There are some ways of figuring out how to use the paths that aren't ways you'd guess. I'd look at those templates and see how that works.

 

How are you monitoring? FRFR? headphones? studio monitors?

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I'd typically want to use path 2 for an aux in or mic. I'm yet to get that far.

Unless your aux instrument or vocals require a lot of blocks, you can share Path 2's DSP:

  1. On Path 2, create true parallel paths (start with a parallel path and then move both the Split and Merge blocks down).
  2. Set Path 1's Output to Path 2A. Set Path 2A's Input to None.
  3. Use Path 2B for your aux or mic.

In the above scenario, you're using Path 1's whole DSP and half of Path 2's DSP for guitar, and the remaining half of Path 2's DSP for aux/vocals.

 

Obviously, if one's using Helix as a guitar processor only, they have to work pretty hard to run out of juice.

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Unless your aux instrument or vocals require a lot of blocks, you can share Path 2's DSP:

  1. On Path 2, create true parallel paths (start with a parallel path and then move both the Split and Merge blocks down).
  2. Set Path 1's Output to Path 2A. Set Path 2A's Input to None.
  3. Use Path 2B for your aux or mic.

In the above scenario, you're using Path 1's whole DSP and half of Path 2's DSP for guitar, and the remaining half of Path 2's DSP for aux/vocals.

 

Obviously, if one's using Helix as a guitar processor only, they have to work pretty hard to run out of juice.

I think I get you but also think you mean I should split path 1a out to 1b after the effects I want before both amps? Having one 1a as effect into my first amp model and 1b just the effect, then I could take the output of 1b and route that to 2a. Otherwise I'd be feeding an amp output into another amps chain. Actually, this doesn't really work as in the patch I created, for cohesion, I fed the outputs of both heads into a single cab sim and reverb. I guess I could merge the amp heads on path 1 then have my cab and room sim on 2a being fed by path 1. I can only experiment I suppose.

 

Maybe it's not possible but I'd still sooner the dsp could handle more being thrown at it, per path, in it's current configuration. In all likelihood, I'd want to apply parallel processing to my vocal/synth chain too. I've previously built similar setups in DAWs on my 2010 macbook and could also play along with drum software utilizing hefty sample libraries. I'm just surprised that a dedicated, standalone effects processor (even if we're just talking per path) runs out of steam before a 6 year old computer running an operating system and it's myriad background tasks.

 

Also, back to the digital desk comparison. I'm familiar with many other desks but even at entry level.... I've installed a behringer x32 rack at a venue in my home town. Even it you're limiting it to processing it's physical inputs without hardware expansion, this unit processes 22 channels of incoming audio (including aux ins) with a gate, comp and fully parametric eq (including high and low pass). The same processing can be applied to all outputs. Again, if we're limiting it to the physical outputs it has, thats around 14 (including aux outs) I think. Besides all this you have a rack of 8 stereo or 16 mono effects, the sends to each can be processed with the afore-mentioned dynamics and eq, as can the returns. I'm sure it's possible but I'm yet to make it grey effects out due to lacking dsp. Oh, on top of all that, it animates input and output metering, rta on eq visualization and gain reduction on dynamics. 

 

Granted, the modeling/processing in the x32 might differ greatly from that within the Helix... but that's a hell of a lot of processing that by comparison, what's considered an entry level digital desk is capable of.

 

Anyhow, I'm not hating on the helix, I'm just very surprised that my very first foray into patch creation, maxed it (that path) out. I think the routing is really clever and patch editing very intuitive and I'm sure I'll find a way to make it all work for me.

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I think I get you but also think you mean I should split path 1a out to 1b after the effects I want before both amps? Having one 1a as effect into my first amp model and 1b just the effect, then I could take the output of 1b and route that to 2a.

Exactly. Path 2A acts as an extension (both visually and DSP-wise) of Path 1B.

 

I've previously built similar setups in DAWs on my 2010 macbook and could also play along with drum software utilizing hefty sample libraries. I'm just surprised that a dedicated, standalone effects processor (even if we're just talking per path) runs out of steam before a 6 year old computer running an operating system and it's myriad background tasks.

One should never compare embedded DSP solutions with computer-based ones. DAWs are optimized to run tons of stuff at once with dynamic memory buffers, at the expense of unusable realtime throughput latency and the inability to quickly swap modules/blocks in and out. If Helix was designed to work only for project playback (and not realtime), we'd throw a Raspberry Pi in the box, load Linux, and call it a day.

 

Your X32 uses embedded DSP as well for the same reasons.

 

Also, back to the digital desk comparison. I'm familiar with many other desks but even at entry level.... I've installed a behringer x32 rack at a venue in my home town. Even it you're limiting it to processing it's physical inputs without hardware expansion, this unit processes 22 channels of incoming audio (including aux ins) with a gate, comp and fully parametric eq (including high and low pass). The same processing can be applied to all outputs. Again, if we're limiting it to the physical outputs it has, thats around 14 (including aux outs) I think. Besides all this you have a rack of 8 stereo or 16 mono effects, the sends to each can be processed with the afore-mentioned dynamics and eq, as can the returns. I'm sure it's possible but I'm yet to make it grey effects out due to lacking dsp. Oh, on top of all that, it animates input and output metering, rta on eq visualization and gain reduction on dynamics.

IIRC, Behringer's X32 has two ADSP-21371 SHARCs running at 266MHz, and that horsepower is shared across all inputs, channels, sends, inserts, effects, and outputs. Both Helix and StageScape M20d have two ADSP-21469 SHARCs running at 450MHz (the fastest non-Tiger SHARC SHARCs you can buy). So yes, both Helix and M20d have considerably more horsepower than the X32.

 

Basically, if Helix had the same code as X32, it'd be able to run hundreds of EQs, compressors, and effects (or dozens of original PODs!). However, modern professional-level amp and effects modeling is a lot more sophisticated and DSP-intensive. Strymon pedals have a dedicated SHARC DSP (likely faster than one of the two in X32) for one effect only.

 

We've spent a lot of time making sure that the vast majority of use cases can be accomplished with Helix's SHARCs, but there will always be people pushing the limits. A lot of the factory presets showcase some of these extremes.

 

Cheers!

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Unless your aux instrument or vocals require a lot of blocks, you can share Path 2's DSP:

  • On Path 2, create true parallel paths (start with a parallel path and then move both the Split and Merge blocks down).
  • Set Path 1's Output to Path 2A. Set Path 2A's Input to None.
  • Use Path 2B for your aux or mic.
In the above scenario, you're using Path 1's whole DSP and half of Path 2's DSP for guitar, and the remaining half of Path 2's DSP for aux/vocals.

 

Obviously, if one's using Helix as a guitar processor only, they have to work pretty hard to run out of juice.

That's exactly what I was after thanks

I would never have worked out how to do that from the manual. I didn't realise you could split path 2 into parallel and give them different inputs

This thing really is mind bending :)

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