This is my 2nd favorite tuning with a balanced sound signature and a smoother natural detailed tonality that has a reference characteristic. Bass has extra weight but not too elevated, definitely north of neutral, but not as emphasized as in 70, mids/vocals are smooth, natural, detailed, treble is crisp and clear, detailed, giving the sound higher resolution while still keeping it non-fatigue. It would suit audiophiles who want resolution and natural coloring of the sound without too much bass emphasis or too energetic treble. Soundstage is very wide, and imaging is nearly 3D holographic.
The tuning of 60 is closer to ES60 version, unlike 80 and ES80, but ES60 is still a little more forward in upper mids and slightly more sibilant in lower treble. I actually prefer MACH 60 over ES60. The tonality of tuning is somewhere between 70 and 80.
This is probably my favorite tuning with W-shaped balanced signature that has extra emphasis on bass along with a natural detailed tonality. 70 tuning has a deeper well-controlled bass with a tight mid-bass punch, clear detailed natural mids/vocals, and clear non-fatigue treble. Good natural resolution and retrieval of details. This will target a mainstream breed of audiophiles who like more weight in low end without compromising details or resolution. 70 scales up the performance of 80 with more bass (deeper extension, more rumble, stronger punch) and more body in mids. Soundstage is very wide, and imaging is nearly 3D holographic.
This model has a flat neutral sound sig with natural tonality, linear tuning with no boost or exaggeration, very clean and clear sound, good level of resolution, good retrieval of natural details. Overall, the tuning is rather flat, not as exciting since there is no coloring and the sound is more reference. The tuning will be perfect for mixing studio engineers. Not sure audiophiles will enjoy it as much. Soundstage/imaging is more focused on depth than width.
When comparing MACH 80 to ES80, CIEM version has a more balanced tuning, rather than flat, with more weight in the bass and more body in mids which give vocals and instruments a more energetic natural coloring. Also, CIEM version has a wider soundstage expansion. For me personally, I preferred ES80 tuning over MACH 80. ES80 was aimed at audiophiles, and I think MACH 80 will suite sound engineers.
From what I have been told, MACH series was supposed to capture ES sound in a uni shell design. And Westone certainly did try to accomplish that. But in my personal opinion, with help from Ety engineers under Lucid Audio umbrella Westone created a new unique series with its own audio personality, especially when it comes to MACH 60, 70, and 80. Their other IEMs (10-50) will appeal more to musicians and casual listeners, and probably not as much for picky audiophiles who have higher expectations. For me personally, given a choice between all 8 models, I did enjoy more listening and comparing 60, 70, and 80.
Overall, MACH 60 has my 2nd favorite tuning with a balanced sound signature and a natural, detailed tonality where the bass has extra weight, mids & vocals are smooth, natural, detailed, and treble is resolving, crisp, and clear. MACH 70 is my favorite with its W-shaped balanced tuning and extra emphasis on bass to bring more weight and tighter mid-bass punch along with a clear detailed mids and non-fatigue natural detailed treble. MACH 80 gives you a flat neutral sound sig with a natural tonality, and more reference tuning without coloring the sound which I found great for analyzing without having “analytical” tuning.
Also, keep in mind that MACH series switched to Linum T2 (IPX connectors) cables. It is no longer mmcx which is a blessing and a curse at the same time. IPX plug connectors are a lot more reliable, but also less common. At the same time, many Westone users I talked to in the past don’t even cable roll, and I have a feeling the same will be true with MACH series. And while a new cable might have a polarizing opinion, there is no argument about new shell design still being very comfortable to wear for extended period of time, even in bed with your head on the pillow. While no longer bean-shaped, they are still very ear-friendly.
In conclusion, Westone is 60+ year old company, still around, still working on new releases, still trying to stay relevant, still trying to please their existing customers and to attract new ones. In my opinion, MACH series still keeps the DNA of W and ES series without drastic changes outside of their traditional house sound tuning. The current IEM competition is fierce, and the audiophile crowd is not easy to please. But I think MACH series still brings something different and unique to the table, especially with their 60, 70, and 80 models. So, check them out when you get a chance!