Sometimes when you turn it up it hurts. Of course there are many types of music where this is desirable, too a degree. For example some types of punk, metal, industrial, noise etc. can benefit from sounding a bit hard. However for the majority of music, 'treble that hurts' is usually deemed by the listener to be 'a mistake' or can lead them to think, "I'm not sure what's wrong, but the track sounds unfinished/unprofessional". Here are some strategies to help combat a harsh high end at loud listening levels. They can be applied to individual instruments or the full mix, but the regular advice applies here: 'Try fix the mix first'.
This is always the first thing to try. Thanks to Fletcher, Munson et al we know in great detail how the ear is more sensitive to certain frequencies than others. If you find that a certain sound in a track is 'hurting' a solid strategy is to:
This might be old news to you, but a trick that I usually like to do after this is:
This boosts the surrounding frequencies a touch, now when you bypass/unbypass these two EQs the sounds before/after match more evenly; it's easier to compare. To the ear it sounds like you're effectively 'spreading' the hurting frequency into the surrounding frequencies, which can really smooth things out and give more space and size.
EQ is very powerful! It's easy to turn your song into an overly smooth sounding mush which, more often than not is undesirable. If you want your mix of sounds to still have clarity, punch and snap keep this in mind as you work, taking care not to go too far. Even better, reference against some tracks you like that have a good balance of smoothness/clarity.
Hopefully after trying EQ you'll find the problem solved and you won't need to try this step (which is more invasive). Altering the dynamics of the treble can be a great way to soften the sound, make it sound smoother and even 'more analogue'. What you will need is the high band of a multiband compressor, a de-esser or a dynamic EQ. Now unfortunately multiband compressors and dynamic EQs tend to be complicated, and it's easy to get lost in their interfaces and lose sight of the job at hand. Some de-essers (and we're not just talking about using these for vocals only, de-essers can be applied to any harsh sounds) are more simple to use, but can also be complex. The point to remember here is we're looking to focus on the harsh treble area only, if you can its worth using or setting yourself a few starting point presets that set up your chosen tool to focus on this area.
So these articles are not about specific gear, and I try not to mention gear by name because I think it fosters the wrong approach; gear is just a means to an end. But due to the complexity of multiband compressors etc. it's worth mentioning that some free and paid plugin favourites of mine are:
So the aim when using any of these tools for this purpose is to slow the response of the treble and smooth it such that it sits at a more consistent level.
Spitfish is a simple to use de-esser designed for vocals but can sound good on most instruments (even a whole mix if used sparingly). It's advantage is it's quick and easy and has only a few parameters to tune. Don't feel too big to use this deceptively simple tool, like anything in mixing or mastering you want to identify a problem quickly (in this case harsh treble) fix the issue and then move on just as quickly. If you spend too long tweaking a complex dynamic EQ you risk over-listening to the track and 'muddying' your ears for that session. Spitfish is quick to use and often can get the job done so remember you don't demonstrate your cleverness by utilising the most complicated multiband gadget you can find, you demonstrate your competence by working through a track swiftly and professionally, improving as much as you can within a given session time. (Just remember to turn on the 'stereo' option if you're using Spitfish with a stereo track.)
Saturation here means valves/tape/analogue outboard all of that sort of stuff, but again I'll break my normal rule and mention another plugin by name. Klanghelm's free IVGI is an excellent and simple analogue emulator that can tie hard highs together in a really smooth way with minimal tweaking time. It's bigger brother SDRR is also recommended if you need more options and the valve emulation in this one is quite good sounding. Even if you only use IVGI the Klanghelm plugins are such good value that you should at least buy one to say thanks for IVGI.
The idea here is similar to the previous treble dynamics technique. This time you're looking to 'drive' your signal into the saturation processor and listen closely how it affects treble. You're listening for that softening sound, which will get softer as you apply more drive. This is often not as pronounced as using dynamics as before to compress the treble, so expect a general 'analogue gelling' sound rather than dynamically controlled highs.
My preferred starting point for IVGI is to have the 'ASYM MIX' at 7 and then gradually increase the drive to get more softening. Remember with saturation tools like these you'll be affecting the whole mix, not just the treble, so be careful and keep an ear over the whole mix as you apply. As always striking a nice balance, bypassing/unbypassing to make sure you've not gone too far and not being afraid to abandon the technique if it's making things sound worse.