Rubber tips are traditionally used just to supply isolation and a comfortable fit but on the Sennheiser CX 980i they give you some control over the sound of these earphones. Each rubber tip size comes also comes in two colours - pink and white. Don't worry, the coloured bit is the inner part of the tip, which you won't see in normal usage.
With a longer and slightly thicker column, the pink version supplies a bit more bass, while the white tip is what Sennheiser claims as the "balanced" alternative. In truth, both are pretty bass heavy.
After experimenting with both the pink and white tips, we discarded the pinkies, as the last thing the CX 980i bass needs is a boost. Like the lower-end CX-series models, the low-end here is a little inflated, and isn't particularly well-controlled when matched with the pink tips. The white tips offer a noticeable improvement, but they still have a booty much wider than the vast majority of £100 earphones.
A big old sonic backside can be great, but the CX 980i could do with a little tightening-up in this area. Swapping between these and the equally-voluptuous Sennheiser IE8 shows quite what an anomaly the top-end IE8 are, as a bass-heavy earphone whose sound is almost beyond reproach. However, they are more disciplined and tauter than the CX 980i. These earphones carry the sonic DNA of the CX series, and as such have inherited a bottom end that wouldn't get through finishing school without some additional deportment and elocution lessons.
What they have also inherited though is a warm, smooth sound that is immensely easy to get on with and, almost always, a joy to listen to. There's not a hint of sharpness or sibilance to be heard, and while the bass tends to dominate over the treble a little, the top-end isn't veiled or murky. This sound signature feels out of place at this price though, much as it's a similar balance to the quite wonderful Sennheiser IE8i. At £199, bass bloat shouldn't really be here - suggesting that we're paying a definite premium for the snazzy design.
If design matters a lot to you then fair enough, but for our money earphones like the Phonak PFE 112 offer higher fidelity for less money while still giving you control over your sound - using custom filters rather than custom tips this time. If you want to stay within the Sennheiser stable, the top-end IE series also offers better sound quality. The IE8i are available at a similar price, but if your wallet won't stretch that far the IE7 are available for less if you shop around enough. If you don't absolutely need a handsfree kit, the remote-free non-"i" model of the CX 980 earphones is available for £50 or more less. A better buy in our mind.
Far more stylish than the vast majority of Sennheiser's earphones, the CX 980i are sleek and exceptionally well-made. They sound good too, with that Sennheiser smoothness we know and love, but we don't think they quite sound £199 good. A less than perfectly-controlled low end stop these buds from coming close to matching the best at the price if you only care about sound and not looks.