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Blackface Dbl Vs Vib
by CairnsFella on 2012-12-11 00:15:55

Hi all,

Another ametuerish question... Sorry.

following my jaunt through all of the FX on the HD500 and - where possible - comparing them with on-line videos of the real thing, I decided to do the same with the amp models.

Straight off I have run into some confusion regarding the nrm and vib variants of the Blackface model. I guess I subconciously realised that there would not be any actual reverb or vibrato on the model itself, it does leave me wondering what the intended difference is between these models. My ear my not be up to the standard of you experts, but to me the vib variant is the same as the nrm, but with some additional 'noise'. Now having watched a couple of vids of the fender twin reverb in action it is clear that this channel is noisier, but surely that not all there is to it? I have looked, but unless I am missing something obvious the vib model doesnt even get described (or at least seperated out from the nrm) in the model gallery or HD guide.

Can soemone tell me what I am missing here?

OK.. scrub that. I am getting some tonal difference aside from the noise. Interesting though, as from what I have researched the channels on the real thing are more similar. I guess there may be some other setting change (though I have ensured my parameters are the same). I wisjh there was more tech info sometimes, rather than the headlines quotes, soundbytes and name drops they use in the descriptions.

Anyway, sorry to have taken up your time.



Re: Blackface Dbl Vs Vib
by jimsreynolds on 2012-12-11 02:50:59

It is probably worth checking out the Model Gallery here -->  http://line6.com/data/6/0a06434d408c50904b6a219d8/application/pdf/POD%20HD%20Model%20Gallery%20-%20English%20(%20Rev%20D%20).pdf">http://line6.com/data/6/0a06434d408c50904b6a219d8/application/pdf/POD%20HD%20Model%20Gallery%20-%20English%20(%20Rev%20D%20).pdf">http://line6.com/data/6/0a06434d408c50904b6a219d8/application/pdf/POD%20HD%20Model%20Gallery%20-%20English%20(%20Rev%20D%20).pdf

There are a couple of amps that have multiple channels modelled and the differences can be quite subtle.  In the case of the Double...

"Blackface Double NRM: The Normal channel is the mellower of the two, with less gain

than the Vibrato channel.

Blackface Double VIB: The Vibrato channel is a separate preamp circuit with clipping

characteristics that are different than the Normal channel due to an additional 12AX7 tube

stage."



Re: Blackface Dbl Vs Vib
by hurghanico on 2012-12-11 03:00:22

CairnsFella ha scritto:

...I have looked, but unless I am missing something obvious the vib model doesnt even get described (or at least seperated out from the nrm) in the model gallery or HD guide.

Can soemone tell me what I am missing here?....

you are missing the latest and updated version of the HD model gallery



Re: Blackface Dbl Vs Vib
by MartinDorr on 2012-12-11 10:41:06

I did some input level + Drive to output level measurements for both the BF Double Normal and Vibrato Preamp channels w/o Cab models in the past. I found that both amps start to produce an artificially compressed, soft clipping and even distorted output signal if the output exceeds -12dB. The more it exceeds teh -12dB the worse the effect gets. So in order to comapare apples with apples I adjusted to input signal so that the output signal at 100% Drive, %50 Bass, 50% Mid, 50% Treble, 50% Pres, and 100% Volume would get -12dB output signal. This is not practically useful, but it shows the differences between the 2 amp models:

  • To do this the Normal channel requires a -19dB input signal whereas the Vibrato channel requires -35dB, i.e., a 16dB difference!
  • 0-100% Drive controls 52dB volume change for the Vibrato channel whereas 60dB change for the Normal channel.
  • Besides tonal differences the setting of Drive causes different level changes for the 2 channels. If I list the output level for every 10% Drive increase at 100% Volume I get the following (cut and past it into a spreadsheet to see a graph). Note, the same relationship exists at any Volume setting, e.g., at 50% Volume everything is just 12dB lower.

        Drive     Norm        Vibr

            0        -72          -64

          10        -60          -55

          20        -48          -43

          30        -38          -31

          40        -33          -23.6

          50        -29.8       -19.0

          60        -25.1       -18.4

          70        -19.6       -15.3

          80        -14.6       -14.7

          90        -12.1       -13.3

        100        -12.0       -12.0

If you graph the numbers you get the interesting picture below . Looks like interesting Drive settings for the Vibrato channel are up to 40% for pretty clean, 50-60% for a little break up on the high volume notes, and above 60% with very little volume change al the way up to 100%. On the Normal channel on the other hand up to 0-30%, 30-55%, 55-80, and above should give you different results. Note, this is only about playing volume level response. Tone is another story. Enjoy

TV-TN comp.jpg



Re: Blackface Dbl Vs Vib
by Akeron on 2012-12-11 12:03:00

Really interesting but can't understand the meaning of the data. The negative numbers are clearly not Volume A and B POD Mixer values because the maximum value before "Mute" is -59.5dB, so where they come from? Can you show the exact process with the DAW and the POD settings?



Re: Blackface Dbl Vs Vib
by MartinDorr on 2012-12-11 12:49:40

Ah yes, sorry I was in a hurry ...

I record a loop (a few hard strums) and have the looper in pre position as my repeatable level sound source. Put the Studio EQ in front of the Amp. Select the Amp to measure and set Drive and Volume to 100% and the rest to 50% or whatever tone setting you are interested in. Set the Mixer channel A to Center 0dB gain and channel B to muted (I think it is not just -59.5 dB but fully Muted when it says so).

I measure the output signal via USB and GarageBand, all levels in audio driver, DAW, and plugin set to unity gain with an Izotope Ozone 4 plug-in because I have it and it has a nice meter, but I'd guess other DAWs will do something similar.

Start by changing the Studio EQ's gain so that the Amp output (100% Drive, 100% Volume) is -12dB in your DAW (this does not work for all Amps, see alternative below at different Volume settings). Disable Amp, make sure Bypass Volume is at 100% and check Amp input signal level. If input is above -12dB lower Studio EQ gain until it is to avoid compression/distortion from Studio EQ. Write down the input level (mine where -19 and -35dB for the Normal and the Vibrato Preamp/noCab, respectively) . Reenable the amp and lower Drive to 0% and start measuring output level for every Drive selection you are interested in.

There is no hard need to normalize to the 100% Drive / 100% Volume / -12dB output level but it makes it easier to comapre different amps. You can get the same Drive characteristic for any constant Volume setting (as long as the max output does not exceed the -12dB.

In practice I think the only thing to watch for is the -12dB output rule. As long as you stay below -12dB the Drive dependent gain curve stays the same no matter what volume setting you picked for all measurements. Once you exceed the -12dB the curve gets compressed (output lowered, soft clipping up to plain digital sounding distortion) in the area that is above the -12dB output level. The same is also true for the Studio EQ and the Mid Focus EQ. I'd guess for other effects as well, but maybe not for the same threshold.

I am in the process of measuring all PreAmps and plan to do the same for the effects I am interrested in as I go. This was just lucky timing that I did those BF Double PreAmp numbers a good week ago. Before I forget, don't just trust what I say. It would be best if independently confirmed or corrected.

Hope this helps (and is right). Let me know if not.

Regards,

Martin



Re: Blackface Dbl Vs Vib
by CairnsFella on 2012-12-11 17:57:33

Re: Blackface Dbl Vs Vib

It is probably worth checking out the Model Gallery here -->

Re: Blackface Dbl Vs Vib

you are missing the latest and updated version of the HD model gallery

Appreciated guys. yes, my model gallery doc was out of date, so I apologise for the error on my part.

In fairness, I had rather retracted my initial enquiry so I was suprised to see the ensuing debate. Your assistance was nonetheless much appreicated though. Thanks guys.



Re: Blackface Dbl Vs Vib
by CairnsFella on 2012-12-11 18:06:57

Interesting figures Martin.

Whilst a little off topic (though as OP I give myself dispensation) I rather wish each of the modules could report the levels input / output in the form of a meter or somesuch. Having taken some time to go through all of the effect models 'one at a time' I found certain input levels were much more preferable to others (though I realise this is a personal prefence issue). However, once chaining effects together it becomes a bit of a lottery (or perhaps more fairly, a tricky balancing act). If meters were available, it would make the chaining of effects much easier, and perhaps more importantly help balance final outputs for each patch.

I guess this would be a bit extreme for a feature request (although even simple peices of gear from many years back would often contain some form of meter, so Im not that sure it would be a massively difficult task).



Re: Blackface Dbl Vs Vib
by Akeron on 2012-12-12 05:44:46

Thanks for the explanation Martin! I did the measuring myself of the output levels, with Reaper and the internal plugin "vumetergfxsum", but I get very different results from yours, don't know if it's a problem with the precision of Reaper or my method (but I think it's the first one):


Drive   Nrm

====  ===


  0        -39.8

10        -39.0

20        -36.5

30        -33.5

40        -30.7

50        -28.0

60        -23.6

70        -18.6 (-18.5)

80        -14.6

90        -12.1

100       -12.0

I stopped here because the results were different and because I haven't found a way to measure the exact values of the input levels. All I can see from the meter of the track is a line that goes a bit above -18, could be -16 but can't be sure because there are no lines above. Assuming I did all like you did, there are still some things I don't understand:

1) The amp never goes above -12dB when in Bypass mode with every setting of Drive, so I don't understand the part where you tell to check it

2) If I've understood correctly, the only number that matters is the input volume with 100% Drive, so why do you have to measure all the others?

3) How can you use in practice those values in the patch?

4) In the end you do say "The same is also true for the Studio EQ and the Mid Focus EQ"... but that sentence confuses me. Are we measuring the compression of the distortion of the EQs or the amps?

5) How you visually detected that there was a "soft clipping" exactly at -12.0dB in the first place? The meter in Reaper doesn't clip if you don't raise the Gain in the Studio EQ to a certain level...

By the way, to get 12.0dB at 100% Drive with the Blackface Dbl Nrm, I've used -15.1dB of Gain in the Studio EQ.



Re: Blackface Dbl Vs Vib
by MartinDorr on 2012-12-12 08:18:15

The model gallery is a good start but if you want to dig deeper you may also want to check out the Fender docs at

http://support.fender.com/manuals/guitar_amplifiers/65_Twin_Reverb_manual.pdf

I realize it would have been really nice from Line 6 to describe which of the 2 inputs they modelled and whether the Bright switch was on or off. On the other hand though I am getting the feeling that the Line 6 models are not exactly modelling all the knob settings as they exist on the real Amp. For example, they could simply determine a real Amp knob setting for some Line 6 internal frequency response target and then put a more generic tone stack model on top that adds various knobs that do not exist on the real Amps, e.g., Presence for the BF Double, Mid or Presence for the BF 'Lux. I have no experience with the real thing, but it would probably take some real familiarity with the real equipment to make a call on what Amp features the Line 6 model actually models.

Enjoy,

Martin



Re: Blackface Dbl Vs Vib
by MartinDorr on 2012-12-12 09:26:08
  • Based on the level range that the Drive settings produced I'd guess you are checking the full amp and not the preamp model. I have seen similar numbers for other Full Amp models but I can't check till tonight to be sure.
  • I don't know your guitar's signal output level (setup, pickups) and whether you are coming in as Guitar, Variax, or both and what you selected as Input 2, i.e., you might produce an Amp or Studio EQ input signal that is higher than -12dB. In my experience this causes compression and model behavior I cannot predict in terms of signal levels (the sound may be OK for what you want).
  • Drive does not do anything in Amp Bypass mode, nor do any of the other Amp knobs or settinsg like Cab, ER or Mic. The Bypass mode check is just so you know what your Amp input signal level is.
  • In practical use and atteming to minimize effect or amp compression/distortion purely due to signal levels while maximizing the level throughout in the HD signal chain I do the following:
    • Use the input mode with the least artifacts or noise (e.g., use Input 1 = Guitar, Input 2 = Variax for regular guitar, or Input 1 = Variax, Input 2 = Guitar for variax users, I get 96dB noise floor with a JTV-69, Strat model, selector at 2 and my input signal is around -16dB if I hit a few chords hard).
    • Use 1st effect after input (or add Studio EQ) to adjust output level to -12dB max (no matter what you do on your guitar, -10dB for absolute peaks is probably OK too if you want to push levels real high)
    • Add pre-amp effects and make sure output level is close to but never exceeds the -12dB limit, i.e., make sure your volume does not change if you rely on pure listening)
    • Add Amp or Preamp with Drive and Tone stack settings, Cab, Mic and ER as you like and adjust Channel Volume to not exceed -12dB.
    • Add post amp effects using the same -12dB limit rule.
    • Move mixer to the end if you want output higher than -12dB and adjust as needed. If Mixer is not last make sure it does not produce output higher than -12dB to prevent compression in the post effects.
    • Take all the above with a grain of salt, i.e., this is just what I do today because I ASSUME that all effects follow the same rules that I was able to confirm for Mid Focus EQ, Studio EQ,and few Preamps. Obviously there is a lot of assumption and as time goes on I may have to adjust the rule(s) based on what I measure or what additional comments/feedback I read.
  • There was no attempt to measure the EQ's distortion. I only advise you to check the EQ's output and keep it at -12dB to make sure it does not compress/distort and you get the cleanest possible boost/signal into the amp model.
  • You can detect the compression and hear the distortion of EQ effects when you check what the different gain values you dial actually produce with a signal level meter. What I found for the Studio EQ and Mid Focus EQ is that they reduce the output level even when their gain is set at 0dB IF the input level is above -12dB. And if the input level is below -12dB and the gain setting results would result in some level above the -12dB mark you will not get the gain you dialed in but less. Far less if get you closer and closer to the 0dB output level. At about -3dB output you will hear serious digital sounding distortion even though you have not hit the digital signal clipping level at 0dBFS. My take on that is that Line 6 models may simply emulate the anlog equipment behavior of soft clipping and compression in the -12dB to 0dB signal level range. Obviously a big guess at this time.
  • Please be aware that the Studio EQ's dialed in gain may be up to 2dB off from what the dial says even if you are below -12dB. It really is only correct at -18, 0, and +18dB settings The in-between ranges are the worst offender as get more and more away from the 3 exact operation points.
  • Based on your -15.1dB adjustment for your input it looks like your are coming in with a really hot guitar input signal. Make sure the Mixer setting is not masking your true Amp input signal level. I found that for a simple setup like this experiment you need to Mute channel B to avoid a 6dB channel a/B summing gain on output due to the default Mixer setup. Check whether the Mixer adds anything by recording a loop in post mode and then moving the loop to pre position. it should play back at the same level no matter where it is if the Mixer does not add gain.

I really appreciate your measuring and reporting what you find as this is the only way to asure there are no principal setup or measurment errors or invalid conclusions from the results. This must be repeatable and practically useful, otherwise it means nothing.

Thanks for checking more into this and let us know how it goes,

Martin



Re: Blackface Dbl Vs Vib
by MartinDorr on 2012-12-12 09:38:05

Totally agree, a meter and guidanced on how to use it to build tones would be imensly helpful. I could see a simple thing like a flashing display or diplay section with a rate reflecting dBs above some sane threshold a rather simple way of telling what's going on while editing tones on the HD. Obviously the visuals in the editior SW could be much better than that and provide real numbers or simply green, orange, red lines in the signal path display.



Re: Blackface Dbl Vs Vib
by talwilkins on 2012-12-19 15:06:19

Move mixer to the end if you want output higher than -12dB and adjust as needed. If Mixer is not last make sure it does not produce output higher than -12dB to prevent compression in the post effects.

I've read this tip on other messages but I don't have a clue how to do that.

Could you please clarify what you mean here and how to achieve it?



Re: Blackface Dbl Vs Vib
by MartinDorr on 2012-12-19 20:11:37

The only pretty reliable way I have found to check input and output levels is to use USB output to a computer and a DAW to measure the levels. You may be able to do a similar thing with the regular HD output going into a good mixing console or a smart phone with the right application. The potential issue with that latter method is probably to really be sure you don't get messed up with some level miss-match on the analog interface. i.e., unless you have experience with the equipment or SW it may take a while to become confident about what you measure is actually what's really there.

Sorry, I understand this may not be much help but there is nothing else I know of. Maybe some other people on the forum have tried other routes amd can comment.

Martin



Re: Blackface Dbl Vs Vib
by talwilkins on 2012-12-22 16:44:36

What I mean is how to move the mixer to the end? As far as I can tell I can't move it at all.



Re: Blackface Dbl Vs Vib
by jimsreynolds on 2012-12-22 17:36:31

You can't move the mixer itself.  However you can move each and every amp and effect in front of the mixer which has the same result.



Re: Blackface Dbl Vs Vib
by CairnsFella on 2012-12-27 16:58:45

Thanks for the further reading link.

I do feel it is a bit of a shame the models are not more "knob for knob". Despite my lack of familiarity with any of the models, and my happiness with the sound I can get, it would still be nice to feel my virtual knob twists were like for like had I the real amp in the room.



Re: Blackface Dbl Vs Vib
by hurghanico on 2012-12-27 18:28:16

I would say that the controls actually present in every amp are modeled quite well..
the missing
amp controls should be post-amp and have an effect similar to those of a hypothetical post-mixer .. I noted, however, that the missing ones have almost no effect (or very little) on the characteristic amp sound ..

unfortunately in the official description are missing some details ..


as someone already knows, some time ago I made ​​a compilation of the included amp models where you can see the actual controls of every amp:

http://line6.com/support/message/395729#395729

for the bright switch on or off I can't know if it was off or on (I would say: probably on, like in the old XT/X3)..



Re: Blackface Dbl Vs Vib
by CairnsFella on 2012-12-29 19:24:43

hurghanico wrote:

I would say that the controls actually present in every amp are modeled quite well..
the missing
amp controls should be post-amp and have an effect similar to those of a hypothetical post-mixer .. I noted, however, that the missing ones have almost no effect (or very little) on the characteristic amp sound ..

A matter of opnion I guess (and Im quite happy to accept that your opinion would be much more relevant than that of a novice like myself). But I still feel a model should ideally reflect like for like in every instance possible (and I would doubt the omissions would be in the impossible category).

Still.. I am nitpicking. I dont really see this as a drawback per se, just a dissapointment.



Re: Blackface Dbl Vs Vib
by hurghanico on 2012-12-30 07:00:37

Your opinion CairnsFella is as important as mine .. neither more nor less

having said that, now I want to exaggerate and I imagine a hypothetical fantastic modeler:

I choose an amp model and appears next to me a tridimensional hologram of the amp chosen with all the original buttons and potentiometers (including the fuse holder), I activate an effect, and it appears another hologram with all the details (including a corner of rust) on the ground near my feet .. from a scenic point of view it would be really awesome .. might be called POD 3D or something like that..

who knows, maybe one day someone will realize it ..

but how much money all this would cost? .. and especially would serve truly something? .. At that point it would not be better to have the real things? ..

To be honest, I think the POD HD series offer in absolute the best value for money that is currently on the market ..

with an axe-fx that costs (only?) 4 times as much, you may have some more minor details to play with (very few people make a real use of those added controls), and more DSP power available (that's a good thing, but it isn't free), but the point is: are those minor added details really so necessary for what you need to do?..and above all, would you be willing to pay much more to get them?

at the end of the story, in my humble opinion, the level of details and sound quality that I have for the price I paid for my HD500 is more than enough to get just great sound results.. about this Line6 programmers have been very smart to choose the essential ingredients to be included in their modeler..

the only thing that disappointed me a little (still taking into account what I got for the price) is the documentation, a bit confusing on some points and less detailed than in the past..



Re: Blackface Dbl Vs Vib
by CairnsFella on 2012-12-30 16:48:46

Hurghanico,

I would say that in the main we are in agreement.



Re: Blackface Dbl Vs Vib
by hurghanico on 2012-12-30 17:25:40

CairnsFella ha scritto:

I would say that in the main we are in agreement.

I'll remember that:
in the main




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