It is good if you learn the headphones you have, a lot, because you want your music to sound great in most cans and speakers. You can also try to mix in phases where you gradually open up the frequency spectrum and once the mids are rich, then you work on balancing the various ranges of the lows and the various ranges of the highs separately. Most cans and speakers are quite bad, but if you train your ears a lot you can learn to discount that when you evaluate what you have in the mix. Learn the technique well so that you know how to best work with the frequencies. Listen to the sound objectively and practice putting the most precise terms on it, just like describing what a particular red wine is like. Describing sound and music really well is key, no matter what headphones and speakers you use. It is more important than the speakers and the headphones, so do not over estimate their impact... Obviously you are going to need both cans/speakers that have a limited frequency spectrum, and ones that provide you good low end and high end insight too. If you learn to mix against for instance notebook speakers with a very limited high and low frequency spectrum, you kind of learn the art of creating bright mixes. From there the step to creating great sounding mixes on the full frequency range will be a little smaller and easier. If you open it up with cans that lack precision, then that can take some time to learn.
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When you learn the art of describing sound, an advice is not to immediately attach good or bad labels to it all. Balanced might be good and it might be bad. The question to ask yourself is this: How do I like this, what is really what I think and feel about this sound? Maybe some of the music I love out there and would like my mixes to sound similar to, maybe that's not at all the kind of sound I've dialed in here. What IS that sound like, what does it contain? Have I really put the right labels on that sound? Do I need to listen to it using a number of different cans to see how that impacts the labels I've put on those mixes?
I find it's mostly this kind of stuff. Balancing is balancing, you can hear when you have too much or too little lows, mids or highs, but knowing what frequency composition you truly want to have and how to achieve precisely that using any cans, that's what you should be looking into. It's good if you learn to balance a mix per frequency band and can put precise labels on the frequency bands of various sound sources. In that way you learn how to balance the mix towards what you find to be beautiful. You can come a really long way by only using the volume faders really well no matter what speakers/cans you are mixing against, but when you take it one step further - balancing by frequency band - and learn that really well, then you make great sounding mixes on any cans or speakers you have available.
So, focus on objectively describing the sound coming from any cans. Balance precisely enough. Learn what sound you REALLY want to end up with and learn what that sound REALLY contains in terms of frequency content. Use multiple cans and speakers to broaden and widen the perspective on what you're truly hearing, so that you can put more precise labels on what you're hearing or trying to achieve. You cannot achieve all sound characteristics all at once, but you can learn them well and play with them beautifully throughout the course of the mix.
I know this is kind of a little off topic, but I do find this needs to be said. All too often we get focused on details and forget the real issues, it's a big issue when you say something sounds organic when it really doesn't. Or when you say something is soft and the pro sitting next to you turns up the volume and says no it's harsh.
In other words, the art here is really to enhance your music and sound awareness, sharpen the precision in your analytical process, then if that is done in conjunction with great speakers, then even better, but with a great ear you come a really long way. The good thing about that is that you do not have to be super intelligent about the hows and whys, because of your skills about the whats are so great. Let me give you an example: You compare a real B3 sound to the sampled counter parts. Then you give each sound really precise musical labels describing how you perceive them intelligently and emotionally, then you find you love the real B3 so you use that it becomes a success. You never had to precisely explain the whys and hows into it, get confused and end up choosing the sampled version, you just kept it real and it worked.
It is confusing at first when a pioneer (said in general terms) suddenly provides a new term to the language, what is it, what does it mean, how does it work, why was it coined. Signal-to-background noise is a term that explains the degree to which you can perceive a certain element or quality within the mix, what you are focusing on improving is the "signal" and what is distracting the perception of that "signal" is the "background noise", hence the ratio is how well you perceive that mix element or quality in the context. It could as well have been coined signal-to-context noise, but I have found "background" to be a little easier for most to understand.
Signal-to-background noise is a very important concept to understand, because it deals with enhancing the listener's perception about various elements and qualities about the mix. It also helps to provide a better understanding about how various "frequency types" react to each other within the mix. You can work with signal-to-background noise in many dimensions. In the upper dimensions you work with it in the production and arrangement process, in the lower dimensions you work with the console, the fxs and their order. An example would be A) placing a chorus behind a reverb as oppose to B) placing both effects in parallel, where B yields the higher signal-to-background noise ratio.
There is a significant difference between technically not being aware of this concept and being aware of it and working technically with it. It is a concept that applies to song writing, production, recording, mixing, mastering. In song writing it is how emotionally attached you make the lyrics, the emotion/heart is the signal and the brain is the background noise. In recording there are many aspects of it, one being how freely musicians can express themselves through their instruments, meaning how much their instrument/technique is in the way of their musical expressions (musical expressions vs musical abilities). In production there are many aspects of it too, for instance how clear are the chords in contrast with the tunings of the instruments. (with higher quality instrument tunings comes greater chord clearity potential, but in between there is noise you need to remove in order to improve the ratio, things like instrument bleed, false notes played, disharmonic distortion, frequency masking...)
One should not get stuck on the abstractness of this term, it is as abstract as you make it since it scales very well both vertically and horizontally. I use it mostly as a tool to sharpen and broaden my focus, to bring things to my awareness and technically deal with more aspects involved to improve the product.
I like some Sennheiser cans but I find that having a dedicated subwoofer that is isolated from the rest of the sound makes it easier to perceive exactly how much low end I have in the mix. The other aspect about them is that they are quite limited in terms of how they reproduce the stereo field. These weak points are two very critical ones that you need to have a strategy of dealing with. In commercial mixes using the stereo field efficiently is an incredibly important thing. I use several cans, but also a monitoring speaker solution that allows me to hear various frequency bands in isolation (various bands in various speakers). That gives me a very good frame of reference.
In order to better understand your cans, you can playback various commercial mixes through various cans and play the songs through various frequency bands in isolation, you can do this both in L-R and M-S modes to get multiple perspectives on it. In this way you can better understand how they will impact your balancing decisions and make you understand how they reproduce the sound.
Also remember that you can use cans in at least two ways: mixing against their frequency response as if they were flat in which case you get the opposite to their inaccuracies, mixing towards their natural sound (make your mix sound the way the cans make other mixes sound) in which case you try to align the sound to cancel out the inaccuracies. It takes some time to understand the impact of both of these application types, a way of ramping up more quickly is to get a frequency band level insight into each set of cans/speakers and based on that understanding take advantage of both application types to both shape the sound more easily and at the same time also get a higher quality mix balance.
I can recommend that you keep your mixes isolated to at least stem level, so that you have a chance of optimizing various stems against various cans/speakers in mastering. Deciding how to efficiently distribute the mix into stems used during mastering is something that really pays off. Overall it's great to have a great degree of isolation, just remember that transients can be very distracting (lower the signal to background noise), use compression and reverb on particular frequency bands on particular sound sources to harmonize those transients and hence add more emotion to your mixes. An example would be to soften and level out the transients in the bass guitar's upper mids and high end. This will make the bass line slightly more muddy and less separated in the stereo field, but it will help make sound sources like background vocals and electric guitars harmonize really nicely which will provide emotional content that otherwise is simply not there. It will also help separate out the other elements in the stereo field.
