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THE7thHAND

FX Stomp: Downsides of driver resampling from 24/48 to 24/192

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EDIT:  The title has been retroactively changed, because the nature of the topic has changed. What has been established so far is that 4 channel recording at 24bit/96khz is possible, but only with driver resampling. The question now is whether there is any other downside to the driver resampling other than latency in monitoring (which could be fixed by direct monitoring)?

 

Hey guys,

 

I'm considering buying a HX Stomp as my main audio interface. What's unclear to me is how many sources I can record simultaneously at 96khz/24bit. For example, can I record two wet (with helix effects) guitar signals and two stereo synthesizers (6 inputs in total), with that quality?

 

Best regards

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I believe in the above diagram it's referring to a reamping situation. The guitar has already been recorded. If you were to do the above, the Synthesizers are taking up all of the possible places to plug a guitar in. So yes, you can do that, but only if the dry guitar has already been recorded and you are reamping it through the Stomp while you are simultaneously recording dry unprocessed Synthesizer sounds.

 

Perhaps someone better and brighter sees something I'm missing, but I think that's how it is.

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So would it be possible to record two guitars with effects and a stereo synthesizer dry at once (4 inputs simultaneously at 96khz/24bit)?

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You have four phisical inputs hardwired to four USB inputs (5-8). 1-4 are processed signals connected to those phisical inputs (or taken from USB output).
Helix works at 24/48. 96khz is done by driver resampling.
You can expect problems with monitoring when Hx is used as your monitoring center. Round Trip latency is quite high so monitoring thru DAW is problematic.
Conclusion: Using Stomp ar even Floor/Rack as an main audio interface may not be a good idea. 

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Oh, that's a shame. But doesn't the HX Stomp has a direct monitoring option, that would allow me to record two channels with the HX effects and direct monitoring + two dry signals (without direct monitoring?) at 24bit/96khz? Is there any other downside to the driver resampling other than latency in monitoring?

 

Thanks for the replies btw!

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16 minutes ago, THE7thHAND said:

So would it be possible to record two guitars with effects and a stereo synthesizer dry at once (4 inputs simultaneously at 96khz/24bit)?

 

Hmmm . . . yes I think that would work if you create TWO signals within the Stomp, and move the Y block (the entry point of the split) all the way left, hard panning left and right, and then keep them separated all the way to the end. However, you'll eat up the blocks on the Stomp very quickly.

 

I happen to disagree with zolko60, I think the Stomp is a great audio interface. It's a wonderful Swiss army knife, but trying to do what you're suggesting would be really pushing its limits.

 

UNLESS you're willing to spend another $100. My recommendation would be if you buy the Stomp, and want to do a lot of DAW work, use the Helix Native discount that comes with the Stomp to purchase that for an additional $100 (currently it's on sale for even less than that). 

 

That way you don't have to care at all about how many blocks you've used in the Stomp.  You could input two guitars, keep them separated, and use the effects in Helix Native (which allows FAR more blocks than the Stomp anyway) to do to your guitar signals what you need to do.

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Thank you guys, for your help so far. It seems to be a bit more complicated than I initinally thought, so I'm going to explain my situation in closer detail. But first of all: Will the driver resampling to 96khz cause any other issues besides what can be fixed by direct monitoring?

 

I like the HX Stomp, cause it could come in handy as a backup in a live setting. My studio work is mostly recording one guitar or one mic. I do, however, need to be able to use multiple mics (up to 4 would be enough) in certain situation. I use my own external channel strips and preamps, therefore I don't need any inbuilt preamps. Before my purchase, I need to understand how flexible in this sense I will be using the HX Stomp, as well as understanding what the shortcomings of the driver resampling to 96khz are.

 

I had a POD HD500(until it failed on me sadly) and with that I had issues. Whatever I recorded ended up being a bit late in the mix so I always needed to readjust to have the timing right. If I'm not mistaken that also was 24bit/96khz. Is this to be expected with the HX Stomp as well?

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Tragically someone else will have to answer the question of what 96khz resampling will do.  That's outside of my experience range. 

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44 minutes ago, Kilrahi said:

Tragically someone else will have to answer the question of what 96khz resampling will do.  That's outside of my experience range. 

Okay, but at least I now know that I can record four inputs at once. Hopefully someone else will chime in an clear up this aspect.

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3 hours ago, THE7thHAND said:

Will the driver resampling to 96khz cause any other issues besides what can be fixed by direct monitoring?

Well, this is not an "issue". You record 48kHz audio but you process and store it at 96kHz. What you monitor is 48kHz because your interface works with 48kHz sampling rate. On the fly resampling induces some additional latency and this is why 48kHz Class Complaint usage on OSX gives the smalest latency. The only reason to use other than 48kHz sampling rate with Helix as USB interface is compatibility with 96kHz sessions on some DAWs.

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2 hours ago, zolko60 said:

Well, this is not an "issue". You record 48kHz audio but you process and store it at 96kHz. What you monitor is 48kHz because your interface works with 48kHz sampling rate. On the fly resampling induces some additional latency and this is why 48kHz Class Complaint usage on OSX gives the smalest latency. The only reason to use other than 48kHz sampling rate with Helix as USB interface is compatibility with 96kHz sessions on some DAWs.

Oh, now I get it! This answers all questions for me. Thats really too bad, 48khz is not going to cut it for me. The HX Stomp is a great product, as far as I can tell but this renders it useless as a main interface for more serious audio production. But such a package for that price maybe is asking too much.

 

Thread can be closed now, as far as I am conserned. Thanks for the advice. It's been very helpful!

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Whoever told you that 96kHz full throughput is necessary for serious audio production was lying to sell you something. Note that although HX Stomp processes audio at 48kHz, its A/D and D/A converters are 24-bit/192kHz. You are correct that the only downside to driver SRC is the latency incurred by the SRC itself (which should be less than 1ms).

 

Higher sample rates are beneficial when tracking sound effects for pitching way down later or an extremely dynamic string quartet, but the majority of major label records are still tracked at 44.1 or 48 through 24-bit/96kHz or 24-bit/192kHz converters.

 

It gets even trickier when companies tout "32-bit/96kHz" processing, which is marketing b@#$%^*, considering 32-bit floating point processing (which Helix/HX has as well!) is table stakes these days but totally overkill for audio throughput (especially considering their dynamic range is far inferior to ours), and 96kHz—or even oversampling to 192kHz—isn't nearly high enough for nailing the intricacies of certain distortion or amp models. So they're wasting a massive amount of DSP for the models that don't need it, and are woefully lacking for those that do.

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Hey digital_igloo thanks for your input (No pun intended). I see your point and the information you've provided is interesting to me. Does this mean I can record 4 inputs at once at 24/192 as long as they stay dry? I need to read the manual more closely.

 

I think what line 6 offers as a product with HX Stomp is excellent regardless. I had many discussions in my life about the "pointless nature" of HiFi systems that have a "higher frequency range than the ear can hear", how "mp3 files capture all a human can precieve" or that the quality of CD is the standard and anymore detail wouldn't make a difference. In my personal experience listening to masters in 24/48, 24/88, 24/96 and 24/192 I found masters in 24/88 or above tend to be more "gripping" to me. Of course there is fluctuation in quality regardless of this factor, this is subjective, anecdotal and might very well be a case of the placebo effect, but in the end I feel more comfortable working with 24/96.

 

In any case, when I invest in a product like this I like to know what it can do. So the latency is not an issue due to direct monitoring. I can record for channels at 24/48 for sure. Is it posssible to record 4 dry signals at 24/96 or even 192? I will take a closer look at the manual.

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I've read/skimmed through the manual in german and checked the interesting passages in the english manual. Just as a little feedback: I do prefer the more formal in depth style that I remember of the HD500. Unfortunately I couldn't get any information that is as detailed as what is discussed in this thread. Any advice where I can get more in deth documentation?

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2 hours ago, THE7thHAND said:

In any case, when I invest in a product like this I like to know what it can do. So the latency is not an issue due to direct monitoring. I can record for channels at 24/48 for sure. Is it posssible to record 4 dry signals at 24/96 or even 192? I will take a closer look at the manual.

 

Yes, you can record 4 dry signals at 24/96. If you're using a Mac, you'll have to download the actual Mac drivers rather than using the Core Audio drivers. In Windows, you can do it with the ASIO drivers. You would just change those settings in your DAW.

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7 hours ago, Digital_Igloo said:

Note that although HX Stomp processes audio at 48kHz, its A/D and D/A converters are 24-bit/192kHz


In what sense they are 192kHz while Hx has 48kHz clock? Do they make some on chip oversampling?

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2 hours ago, zolko60 said:


In what sense they are 192kHz while Hx has 48kHz clock? Do they make some on chip oversampling?

Is it so that you can record four signals dry simultaniously at 192khz and as soon as you use the DSP effects it gets rendered down to 48khz?

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On 7/12/2019 at 8:59 AM, zolko60 said:


In what sense they are 192kHz while Hx has 48kHz clock? Do they make some on chip oversampling?

Where can I read up on the 48kHz clock of the FX Stomp?

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On 7/12/2019 at 11:44 AM, THE7thHAND said:

Is it so that you can record four signals dry simultaniously at 192khz and as soon as you use the DSP effects it gets rendered down to 48khz?


That would require USB transfer of signals other than 48kHz. Is this the case? IDK
We are told "Guitar In" is 123dB dynamic range. Is this true? IDK
Is "Guitar in" set to 1Mohm something different from "Return In" set to instrument level? IDK
Are there Hx Stomp inputs/outputs any different from Hx FL inputs/outputs? IDK
 

 

23 minutes ago, THE7thHAND said:

Where can I read up on the 48kHz clock of the FX Stomp?


You mean in some documents published by Line6? I have never seen any but if the device is claimed to be Class Complaint and works as Class Complaint under OSX and the only sampling rate it reports is 48kHz you can conclude it is 48kHz.

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I see. Oh man, the documentation Line 6 provides is terrible... I guess that will remain a mystery. Thanks for your help!

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On 7/12/2019 at 1:33 AM, Digital_Igloo said:

You are correct that the only downside to driver SRC is the latency incurred by the SRC itself (which should be less than 1ms).


The actual difference is 9ms only by changing the driver. Resampling in case of OSX multi sample rate Core Audio does not change much unless the right way is to compare 2 times bigger buffer at two times sampling rate. If so the difference is 3ms (12ms to CC).

Class Complaint OSX 48KHz  128 buffer - In 5.917 Out   4.688 = 10.605ms
Multi sample rate Core Audio 48kHz  128 buffer - In 8.667 Out 10.667 = 19.334ms
Multi sample rate Core Audio 96kHz  128 buffer - In 10.333 Out  9.333 = 19.666ms
Multi sample rate Core Audio 96kHz  256 buffer - In 11.667 Out 10.667 = 22.334ms

Source: 

 

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On 7/12/2019 at 5:44 AM, THE7thHAND said:

Is it so that you can record four signals dry simultaniously at 192khz and as soon as you use the DSP effects it gets rendered down to 48khz?

 

My understanding from Digital Igloo's post is that if the interface is set to 192khz, and you use DSP fx, they'd get upconverted to 192khz post-processing (since the helix processes at 48k).  So you'd get a 192khz audio stream of the 48khz processed signal.  Plus whatever latency is incurred by the SRC involved in that process.
So, as he said, the only benefit there would be for timestretch/pitch correction in your DAW later (due to more interpolation points), or perhaps pushing up the Nyquist freq to avoid aliasing if you're using crap processing further down the line.

 

You'd mentioned liking the sound, but what are you playing this stuff back on?  I'm only aware of 192khz being used for label archiving of masters...i'm not sure i've heard of any playback medium that supports 192khz beyond compressed formats?
 

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3 hours ago, kelldammit said:

 

My understanding from Digital Igloo's post is that if the interface is set to 192khz, and you use DSP fx, they'd get upconverted to 192khz post-processing (since the helix processes at 48k).  So you'd get a 192khz audio stream of the 48khz processed signal.  Plus whatever latency is incurred by the SRC involved in that process.

Yeah, I'd love to have proper documentation from line6, so this could be cleared up. I'd have no problem ignoring the DSP completly and getting 192khz or at least 96khz. 4 channel 24/96khz would be fine by me. But does it work like that?

 

3 hours ago, kelldammit said:

You'd mentioned liking the sound, but what are you playing this stuff back on?  I'm only aware of 192khz being used for label archiving of masters...i'm not sure i've heard of any playback medium that supports 192khz beyond compressed formats?

 

In my experience there are subtle differences between 24/48 in contrast to 24/88 or higher. I mainly use a PC with a dedicated HiFi card playing different kinds of formats up to 24/192. Those can be recordings of vinyl for example.

 

This article lays it out quite nicely:

https://www.whathifi.com/advice/high-resolution-audio-everything-you-need-to-know

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