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nms

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  • "nms" started this thread

Posts: 165

Location: Canada

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1

Thursday, August 25th 2011, 11:24pm

attn: Marc / Access - looking for some definitive info on the analog vs digital outputs

Ok.. so more than a few people swear the analog outs are a higher quality than the usb or spdif. I've heard the analog outs come from a 96khz source.. is this true? Whereas the digital options generate a source that is 48khz at highest? I'm talking about the source here. Are the analog outs are just a 44/48k source resampled to 96khz? Some definitive clarification on that would be golden!
I record & work at 88.2khz.. so with that in mind, which of these 3 options would give me the best result:
1. USB Audio source recorded to daw. Audio then routed out from daw via my D/A through my 1176 compressor then recorded back into my A/D. I'm doing this to print stereo files through my outboard one at a time. This method causes 2 conversions - D/A->A/D.
2. Analog outs recorded to daw. Audio then routed out from daw via my D/A through my 1176 compressor then recorded back into my A/D. This method causes 4 conversions - D/A->A/D->D/A->A/D
Furthermore, in option 1 if my project is running at 88.2khz.. what sample rate will VC tell the virus to send the audio at.. 44 or 48k? And in that case where does the SRC take place since I'm recording at 88.2k in my daw? Does VC handle the SRC to feed me the 88.2k audio stream which gets recorded?
I'd really like to get some concrete info on this stuff so I know exactly what's going on. Very much appreciated :)

This post has been edited 1 times, last edit by "nms" (Oct 13th 2012, 4:25am)


2

Friday, August 26th 2011, 11:25am

Ok.. so more than a few people swear the analog outs are a higher quality than the usb or spdif. I've heard the analog outs come from a 96khz source.. is this true? Whereas the digital options generate a source that is 48khz at highest? I'm talking about the source here. Are the analog outs are just a 44/48k source resampled to 96khz? Some definitive clarification on that would be golden!


the D/A converters run at 192k by default but they get a 44.1/48k signal from the virus' engine. the 192k are still beneficial because this way some filtering is being avoided.

Ok.. so more than a few people swear the analog outs are a higher quality than the usb or spdif. I've heard the analog outs come from a 96khz source.. is this true? Whereas the digital options generate a source that is 48khz at highest? I'm talking about the source here. Are the analog outs are just a 44/48k source resampled to 96khz? Some definitive clarification on that would be golden!


i don't consider myself to have golden ears but USB sounds fine for me. i'm using a protools HD with 192i/o converters. those are probably a little bit better than what you find in the virus and through those, i like the sound of the virus as much as when i listen to it through the analog outs of the virus. IMO some people get one thing wrong with the USB outs. those outs are not as loud as the ones of some other plug-ins. the reason behind it is that we want enough headroom for the case of somebody playing loads of voices at the same time. you don't want to hit the ceiling and squash the sound digitally.
the USB outs and the analog outs both receive 44.1/48k. the analog outs upscale and i recon that my 192 i/o does this as well (because it also has 192k converters). if you run @88.2/96k you will not get a better sound from the virus.

I record & work at 88.2khz.. so with that in mind, which of these 3 options would give me the best result:
1. USB Audio source recorded to daw. Audio then routed out from daw via my D/A through my 1176 compressor then recorded back into my A/D. I'm doing this to print stereo files through my outboard one at a time. This method causes 2 conversions - D/A->A/D.

and the signal is color by the urei. nice. probably you also get some very mild distortion kind of softens the signal.

2. Analog outs recorded to daw. Audio then routed out from daw via my D/A through my 1176 compressor then recorded back into my A/D. This method causes 4 conversions - D/A->A/D->D/A->A/D

i wouldn't do that. it's not so much that conversions always make things sound bad but they don't help -and- they mess with the timing in many cases. my golden rule is that i go into the analog domain when i want to colorize the sound in any way. if i'm happy with what i have (aka it sounds good to me in the digital domain) i would stay there.

Furthermore, in option 1 if my project is running at 88.2khz.. what sample rate will VC tell the virus to send the audio at.. 44 or 48k? And in that case where does the SRC take place since I'm recording at 88.2k in my daw? Does VC handle the SRC to feed me the 88.2k audio stream which gets recorded?

44.1 and VC does the SRC
marc
The official Virus TI facebook page: http://www.facebook.com/accessvirus

nms

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Saturday, August 27th 2011, 9:26am

Huge thanks for the detailed response Marc :)
the 192k are still beneficial because this way some filtering is being avoided.
^could you elaborate on this? I thought since it's a 44k source the filter would already be implemented at that level.
Also.. when using the analog outs, would it not be preferrable to run the virus at 48khz so it's generating a 48khz source for better quality of sound / less aliasing for feeding the 192k output?
I can go into the config menu and set audio clock to internal but as soon as the usb is connected it forces 'frequency sync to host' even without VC running, so to my knowledge even if I wanted to run the virus at 48k internally it won't allow me to if the usb is plugged in.. is this correct? I use my virus as my main midi hub in my studio so that would be a problem..

I'm on a mission to optimize my rig as best I can so I appreciate the tech info help! I wish I could generate 88.2k sound from the virus though.

This post has been edited 1 times, last edit by "nms" (Aug 27th 2011, 10:12am)


nms

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Posts: 165

Location: Canada

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4

Monday, October 10th 2011, 11:53am

Alright.. just a little clarification here for anyone who comes across this thread..
If the Virus is connected to USB It overrides your ability to choose to generate 44 or 48khz sound from the synth engine and operates as follows:
If your audio interface is set to 88.2khz Virus will generate at 44k internally and VC will upsample it to 88.2khz. Analog outputs will be 44k internally and upsampled to 192khz on its way to the analog audio out.
If your audio interface is set to 96khz Virus will generate at 48k internally and VC will upsample it to 88.2khz. Analog outputs will be 48k internally and upsampled to 192khz on its way to the analog audio out.
So this means the only way to get the virus engine feeding the analog output stage with a 48k signal is to run your project at 48k, 96k, or unplug the usb and run it midi allowing you to regain the ability to choose the sample rate in virus confg.
Past that the only hope is if Access allows retaining the ability to choose clock rate while usb is connected in future OS.
If you unplug usb and set your audio interface to 48k or higher and play high notes with the filters open especially and switch back and forth between 48k and 44k via config inthe virus you can hear the difference of each. It'll be more apparent in some cases than others and vary according to the amount of high frequency content or how much it's being obscured.
There is some occasional dodginess running the usb output.. the slightly oscillating pitch tuning and other things once in a while as well that have not been known to occur when using it in standalone mode. So if you're going to make use of the analog outs it's worth experimenting with feeding the output with 44 vs 48k.