Interesting - when I had a Helix, I remember seeing a video about how to get the best from it when plugged in to a PowerCab FRFR. Basically it said to always leave the master volume knob at maximum and adjust the input levels within the PowerCab to get the levels right; that way you removed one significant variable, which is the position of the Helix master volume, which if it’s anything other than maximum would be hard to set consistently of course.
That said the Helix didn’t have an indication of what the master volume was, and certainly no ability to software lock the volume knob at the time,
The other approach on the Helix is just to not assign the Master volume to whichever output is going to your PowerCab. Then you don’t have to worry about whether it is set to 100% or not. The Helix reverts automatically to unity/100% when the Master volume is bypassed. I suppose this may be the case on the QC as well after the 2.0 firmware drops, which is supposed to include the option to more precisely assign which outputs are controlled by the Master volume.
Good point.
Here’s another question, does the impedance of the headphones have anything to do with the sound crackling or breaking up?
I’ve tried the 250 Ohm version of the Beyer 990s and once I’d tweaked the I/O settings they did sound good (with as I mentioned before some slight break up if you listen carefully)
I’m also intrigued by the Beyer 900s, which I think are 48 Ohms.
Does that mean I am more likely to hear that break up noise that is my ultimate bugbear when listening to any guitar device (ie combo amp/modeller/ etc) through headphones because of the lower impedance, or is it not quite that simple?
Yes - impedance mismatches can cause distortion or more generally impact the accuracy, quality, or volume of the signal in the headphones. It would be useful if Neural would publish the impedance of the headphones output. Although impedance matching does not ensure a great sound through the headphones, mismatched impedances may sound fine, it is a good place to start. Sensitivity, the quality of the headphones, etc., also play a part.
Important to mention that the match is not 1 to 1, it is generally quoted as 8 to 1 (the “Rule of Eighths”). So in the way of a simple example, a 1-ohm impedance source, would be matched to headphones with an impedance of 8 ohms.
Article on impedance matching:
Thank you, I’ll take a look - but in simple terms is it fair to say that the Beyer 900s are not more likely to break up / crackle just because they are 48ohm than the Beyer 990s are because they are 250 ohm?
I would say that you might assume that initially, good chance that they both sound “good” without really drilling down on their qualitative differences which can get pretty subtle. It depends on several factors including the headphone’s sensitivity spec and the volume level being cranked into them as well as their general construction and materials. Since we don’t know the QC’s impedance, no way to tell which is a better match to jump off with, preferable, or more likely to break up, without listening to both and comparing them.
Additionally, there are several headphones that have already been recommended by forum users. You might be able to see a pattern emerge after a while, as to which are working well. Somewhat subjective though - other than the headphones that dramatically under-perform.
Btw, it occurs to me that that as supply chain woes continue on parts/chips, manufacturers find themselves having to swap in alternate parts. Although this may not impact the QC’s headphone output impedance spec, it may get more difficult for manufacturers in general to publish consistent specs for a specific device, as those specs may vary depending on the date of manufacture. Unless if it was a rumor, can’t find confirmation, if I recall correctly, Fractal had to swap parts which actually resulted in a significant performance boost on the revised version of the FX3 (Turbo). Painful if this is true, I would add, for the users who got the earlier version and probably impacts resale value.
I’m a big fan of the Sony MDR7506. Neutral, industry proven, inexpensive, comfortable.
Here is a link that goes to the heart of the matter and beyond
Headphone Impedance Demystified: Do I Need a Headphone Amp? - Headphonesty
I see you have a good link too, i did not see it, sry about that.
No problem, the more the merrier.
I would love to see an adjustable impedance on the headphone output…
I have the DT1990Pro headphones, and I need to turn the headphone output down 12dB to reduce hisssssssss when using a clean amp model and not playing.
Anyone have an opinion about open-back vs. closed-back cans for modeler play. Bleed is not an issue for me. I’d primarily use them for guitar practice. I just want the best headphone experience for that beautiful Neural tone.
They say open gives a better image, i have only open so i am not sure.
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As you can tell from me starting this thread in the first place, I’m no expert - but in my limited experience I’d agree that open sound, well, more ‘open’, and therefore amp-like than closed…
Ok, I managed to try a pair of the (more expensive) DT900s; and while there are some features I really like about them, for example the removable cable, overall I have to say the sound was really disappointing, and much more ‘coloured’ to my ears when compared to the cheaper DT990s… BUT, Regardless of the different impedance on these headphones (very noticeable when comparing like for like) I still get the crackling sound fairly frequently, even having played a lot with the IO levels, output levels et cetera.
Out of interest can anyone explain to me what the ‘Impedance’ setting on the IO page of the Quad Cortex is for?
I wondered if it was to allow me to tweak the impedance to suit the headphones I’m using, but it didn’t seem to make all that much difference in the higher impedance headphones (the 990s) although there was a bit more of a noticeable difference in the lower impedance one (the 900s)
The ‘Impedance’ setting on the IO screen is for the Inputs , not for the Headphone output.
It is designed to match the Input Impedance of the guitar plugged into Input 1 or 2.
It really depends if your pickup are ‘hot’ (ie: powerful / loud) or not …
On some guitars changing the impendance has an effect on the high end frequencies whereas on other guitars it doesn’t change anything … (Impendance has a very noticable effect on my Ibanez RG421 pickup brighness , whereas on my Music Man JP15 it doesn’t change anything, probably because the JP15 has an ‘active’ electronic, powered by a 9V battery, and the Pickups are really hot ! )
Unfortunalty, Neural DSP has not mentionned the QC Headphone output impedance , you should contact support for this specific point…
Check the input jack of the headphone, i have send an item back cuz i thought it was broken, it wasn’t, , unscrew the 6.3 and screw it on again, play with it, that may be your problem.
As I said im my earlier reply here. Ive tried a few sets of lower impedance headphones with the QC and all had some distortion and crackling as you mentioned no matter what combinations I tried with the master and HP output values. My HD6XX never get these artifacts/distortion but they also require the HP output to be maxed (+12db IIRC) and the main output knob to be between 80-100 to get a volume that overcomes the sound of me strumming the guitar itself (open back headphones)