It’s a common knowledge that a smaller eartip with a looser fit will cause a poor seal resulting in reduction of bass impact and the perception of mids/treble to be brighter. The same way how foam eartips, not just Comply, usually suck the energy out of treble and lift the bass quantity up. The “soft” silicone cap sometimes can’t hold the shape to make the best seal, while the exposed foam could absorb the sound reflection inside of your earcanal. So, when you combine silicone cap with a foam underneath to keep its shape – you got Symbio eartips.
Obviously, the results will not be the same for everybody since we all have a different earcanal anatomy, different hearing level, and use different IEMs and sources. But based on my testing using large Symbio W eartips and SP1000 SS as a source, here is how I hear the improvement with a few of my IEMs when compared to their stock silicone tips.
With 64 Audio Fourte and HSA RedCore balanced cable – I hear the bass tightens with more control and a little shorter decay. As a result, there is a better separation with lower mids, also giving a little more body to the mids without losing resolution or transparency. Plus, I hear treble being a little more organic and smoother, but not rolled off. Obviously, improvement in bass and additional body in mids is due to a better seal, but I was also pleased that treble didn’t get rolled off, just an edge taking off to smoother its performance.
With Sennheiser IE800S and stock balanced cable – I hear a tighter bass with a better control and shorter decay. Also, there is a noticeable reduction in thickness of lower mids body which cuts a bit of a bloat, giving these IEMs more clarity in mids. That also results in bringing mids a little more forward, making sound sig more balanced across entire frequency range. This improvement came as a surprise and I didn’t realize how much effect it had on lower mids, improving the clarity and making the sound a little leaner.
With HiFiMAN RE2000 and stock single ended cable – As expected, I hear more control in the bass, maybe even a little bit of reduction in quantity, with overall sound signature becoming more balanced and less v-shaped. Upper mids do gain a little more body, and I hear a more noticeable control in treble, less splashy and a little smoother. All these changes contribute mainly to a more balanced sound signature and a little smoother and fuller upper frequencies.
Of course, the #1 advantage of these eartips is the comfort because you are no longer dealing with flimsy soft caps that provide a poor seal or the dense foamy tips that you have to compress, insert, wait to expand, and only then enjoy the sound. For me personally, these have a benefit of foam isolation and comfort without handicap of the foam sucking the upper frequency energy out. The sound benefits will vary depending on pair up synergy with different IEMs and your earcanal anatomy, but I certainly found the improvement over all stock eartips. Also, the inner core is stretchable and fits variety of IEM nozzles, even some pretty wide ones. I wouldn’t recommend settling on just one type of eartips, you do need a variety to find whatever works for you the best. But I would recommend adding Symbio eartips to your collection because they definitely bring something different and unique to the table. Plus, they look delicious!