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pfsmith0

Global EQ Frequency Response Plots

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I took my HD500 in after upgrading it to 2.62 and measured the frequency responses of the Global EQ. I used an Audio Precision to generate a 100mV RMS signal into the Guitar input (set to Normal) and listen to the SPDIF output. I used a blank patch and panned Paths A/B to full L/R, respectively.

 

Things aren't nearly as interesting as the FX EQs (plotted here for reference) because there are no % labels. Line 6 properly labeled the actual filter parameters and, based on my measurements, they did a pretty good job of getting them right. L/R balance is perfect. No surprises, although my measured Q was x2 what their label says. Not a big deal in my book. Still, attached here are half the graphs. Due to upload filesize limits I had to spread the plots out over two messages. The rest of the plots follow below.

post-1540701-0-47150200-1429584505_thumb.png

post-1540701-0-63754700-1429584514_thumb.png

post-1540701-0-20748500-1429584523_thumb.png

post-1540701-0-45469600-1429584543_thumb.png

post-1540701-0-10895100-1429584569_thumb.png

post-1540701-0-66390500-1429584586_thumb.png

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The remaining plots are in here.

 

Aaargh! I can't upload anymore. You'll have to download the whole shebang here from Dropbox. Sorry...

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Man really good of you to upload these!

Always good to see what the ears are supposed to ear.

Cheers

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great job pfsmith0 !!

 

now, why can't we have an fx block identical to this eq?!?

that would be savable per patch and movable along the signal chain,

I mean even if with only 2 bands at a time but with Hz and dB's instead of % and without analog clipping simulation

 

come on Line 6, put it in v.2.63 !!

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Hurghanico,

 

For you, I will do it.

 

You just want a blank patch with the Global EQ at default settings and then make 2 measurements: Global EQ on/off, right? Please note that I'm just doing steady-state sinewave frequency responses. No dynamics effects (e.g., compression) will be seen.I doubt there are any but if you're hearing a difference then perhaps something like that is going on.

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I notice that the Hi and Low cut will always provide some high and low end attenuation, which might explain some people reporting a difference in sound if the Global EQ is on (default?).  For example the Low Cut while it is -3db at 20Hz is actually starting to attenuate at 100Hz and the high cut is attenuating slightly at 10K even when set to 20K.

 

Did you do a plot for the old firmware with an empty path against which we could compare or was that somebody else?

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great job pfsmith0 !!

 

now, why can't we have an fx block identical to this eq?!?

that would be savable per patch and movable along the signal chain,

I mean even if with only 2 bands at a time but with Hz and dB's instead of % and without analog clipping simulation

 

come on Line 6, put it in v.2.63 !!

 

I've had this basic idea since the global eq was announced. It's on ideascale if you care to vote for it.

 

It wouldn't even have to be an fx block. More like a fixed eq block.

 

But I wouldn't hold any hope for this being implemented in the current hd lineup. For one thing, it doesn't work with hd edit. For another, it doesn't work with all outputs.

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I've had this basic idea since the global eq was announced. It's on ideascale if you care to vote for it.

 

It wouldn't even have to be an fx block. More like a fixed eq block.

 

But I wouldn't hold any hope for this being implemented in the current hd lineup. For one thing, it doesn't work with hd edit. For another, it doesn't work with all outputs.

 

But if the Global EQ was packaged as a standalone EQ that could be allocated to an FX block then it would be available in HD Edit as a standalone fx block and would be within the patch chain - so it would be able to be applied to every output.   I think that is what perapera means as opposed to the actual GLOBAL EQ being assignable and used within each patch.

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But if the Global EQ was packaged as a standalone EQ that could be allocated to an FX block then it would be available in HD Edit as a standalone fx block and would be within the patch chain - so it would be able to be applied to every output.   I think that is what perapera means as opposed to the actual GLOBAL EQ being assignable and used within each patch.

 

That makes sense. One of the things I remember reading about the eq not working with all outputs (all but L6 link and usb), was because of dsp. So if they converted the existing global eq to a movable fx block, that dsp/output problem suddenly disappears? They'd also have to write the interface for the new eq fx for hd edit.

 

I wouldn't count on it.

 

But adding in the ability to save the 2.62's eq data with each patch by using the existing 'inputs setup' would allow for a 'master patch' eq or a 'global' eq, without changing much of anything for what already exists.

 

It would be nice in either case, but I wouldn't count on it.

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....... One of the things I remember reading about the eq not working with all outputs (all but L6 link and usb), was because of dsp. So if they converted the existing global eq to a movable fx block, that dsp/output problem suddenly disappears? ........

 

 

 

 

Yes - they could not provide GLOBAL EQ for all outputs because the architecture of L6 Link, which allows the signal to be "tapped" from several points in the signal path, would mean that several copies of GLOBAL EQ would have to be active, essentially a copy for each "tap" point and from code optimisation they could only free up enough DSP to have one copy of GLOBAL EQ available at all times.  The intent was that the most DSP hungry patch before GLOBAL EQ existed (ie: one that effectively used all available DSP) would still be able to load and run once GLOBAL EQ had been activated - so GLOBAL EQ would be a transparent update even though in effect it has constantly got a little piece of DSP reserved for it.

 

If they introduced another EQ fx module that essentially provided the same parameters and controls as global EQ, then that could be selected by a user and included in a patch just like any other fx.  It would be under DYNAMIC DSP allocation control - just like all the other fx. It would not be GLOBAL EQ but a specific patch EQ with similar controls. The GLOBAL EQ would still be sitting there in the background ready for master venue EQ use affecting all output - but the new EQ module could be used as and when for each patch as needed, and assuming the particular patch has the spare DSP to run it. 

 

As they have the code available and tested and implemented - how difficult would it be to port it to a standalone fx module, assignable per patch and updatable via HD edit? 

 

I am not holding my breath - and I am certainly not counting on it happening - but I think it would be a fairly simple task for them if they chose to do it and it would be nice to have .....           :)

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I meant exactly what edstar1960 described over here...

 

I also wonder how they managed to "optimize" the DSP usage to make the Global EQ compatible even with the most DSP-expensive patches...

 

and I'd add only that a parametric eq fx block should be with 2 bands only to be DSP-friendly

 

not holding my breath neither anyway ;)

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The Parametric EQ basically does the same thing as the Global EQ (except the readings are in %). It should satisfy what many of you are discussing (except for the readings are in %).

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If the suggestion of turning the Global EQ into a per patch EQ is taken up then you know what will happen? Everybody will suddenly want a Global EQ added again to adjust for the environment!

 

Adding a copy of it as a separate effect would be a different situation though - in the FX pack can I ask for a EH B9 please? 

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Really nice job on this and the others you have done. Thank you very much for sharing this...

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The Parametric EQ basically does the same thing as the Global EQ (except the readings are in %). It should satisfy what many of you are discussing (except for the readings are in %).

 

But the Parametric EQ only allows you to select one band along with the high and low shelves. Wouldn't it be good to have one with the same control parameters as the GLOBAL EQ, but be an available EQ fx block that can be added in to a chain as and when needed?  Rather than have to use multiple blocks to load multiple EQ fx blocks to get the same result?

 

If the suggestion of turning the Global EQ into a per patch EQ is taken up then you know what will happen? Everybody will suddenly want a Global EQ added again to adjust for the environment!

..........

 

Are you referring to Duncann's ideascale request?  Or the suggestion above by perapera?   I thought the suggestion was to have another EQ fx block with the same controls as Global EQ, which could be applied to individual patches instead of having to use a combination of existing EQ fx blocks, PLUS, keep the GLOBAL EQ as it is for when you need to adjust ALL your patches at once to a specific venue.

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Having one as new EQ model as well as global would be great, making it patch specific would defeat the purpose of global EQ

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Oh, right. I see. Yes a Global EQ equivalent FX would be more powerful and potentially replace the Parametric EQ.

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I measured the frequency response of my HD500 with the Global EQ turned On and Off and there is a difference as suggested by Rewolf48 above. It's exactly as he said. I updated the zip file of plots as well as included the new plot here.

On-Off.png

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Your work and contributions are greatly appreciated!  I find the visual examples you provided to be greatly beneficial with regards to setting the global eq optimally!

 

Keep up the great work and look forward to future posts!

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Oh, right. I see. Yes a Global EQ equivalent FX would be more powerful and potentially replace the Parametric EQ.

One thing everyone who wants the global eq in an assignable fx block form isn't thinking about: how would they fit all those knobs within the current hd edit interface without adding another tab, making the knobs really really small, or overhauling the entire UI for hd edit?

 

Thanks pfsmith0 for all your work collecting data.

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Hurg, I agree. Yes, there's a difference between Global EQ on/off but I doubt anyone can hear.

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Having one as new EQ model as well as global would be great, making it patch specific would defeat the purpose of global EQ

 

I agree.   :)

 

Oh, right. I see. Yes a Global EQ equivalent FX would be more powerful and potentially replace the Parametric EQ.

 

I agree :)

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Hurg, I agree. Yes, there's a difference between Global EQ on/off but I doubt anyone can hear.

 

i read from the graph that leaving GEQ on we have kinda low + hight cut filtering effects.

may b this explains why some members posted abt 2.62 improving the sonic signature of their patches...

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Yes - while you may not be able to hear above 10K (I can't any more), what you might be able to hear is a reduction in distortion of sounds below that because the higher frequencies are required to represent the sharpest edges of that distortion. Assuming that your sound reinforcement system is capable of reproducing it in the first place.

 

So from the graphs I would say that some people would detect a difference, but most rock guitarists probably can't  ;)

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Screw this talk about your little 4 knob equalizer. 

I want one of these in my Pod 

 

 

 

img31-1349458854.jpg

 

 

And I am going to moan and groan until I get one for free. How unprofessional is L6 to not have one of these. 

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...So from the graphs I would say that some people would detect a difference, but most rock guitarists probably can't ;)

well, with GEQ=off, i cannot hear any difference b2een 2.62 + 2.32 :)

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Great work as usual. Ill try to get these up on my guide soon, but as you mentioned, the param values track actual values closely. Not as essential compared to the other eqs

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