Background: I have used Schuberth motorcycle helmets (lids!) for many years, starting with a C2, then C3 World Edition (original model - not Pro or Basic), and have recently treated myself to a C4 Gloss White & Advanced Comms. I am also a bit of a Schuberth evangelist, having converted my wife (Kim) & a good friend (Brian) to C3 Basic helmets, and mentioning them several times in my Blog. We have two bikes mine is a Honda Crosstourer VFR1200X Highlander (touring screen), and my wife a Honda MSX125 Grom (naked). The below comments are with reference to my experiences on the Crosstourer.
C3: I've been very happy with my C3 which I used with Scala Rider Q1 TeamSet comms for 3-4 years. This helmet is really quiet (my wife & friend are also amazed at the quietness of these lids). I always used to ride with music from my smartphone playing through the Q1 - which was always clear, at pretty much any speed. I have taken many phone calls using this setup which were always clear - in fact I have often said to the caller "I'm on the bike at the mo, I'll call you when I get back to the office", to which the caller would often express amazement "You're on the bike?" - one really couldn't tell - the audio was so clear & wind noise so low, what wind noise there was: generally of a low frequency nature. I always have both vents open.
C4: While I really love the design of this helmet & integrated comms - it has a number of serious issues. The PinLock failed - easy fix. The big issue is wind noise. I find this a bit of a show stopper. Intrusive above 40mph. At 70mph it is really loud. At motorway speeds often I can't tell what song is playing! Phone calls received at motorway speeds are unintelligible - on one, we had to abandon the call as neither of us could understand what the other was saying! With the C4 the noise is of a higher frequency nature. I have tried opening / closing the vents, and while this does help, it doesn't solve the issue.
NB, Motolegends had this to say: "Firstly, noise. Schuberth haven’t announced a decibel rating for the C4. If it had been quieter than the C3 Pro’s 82 decibels, they would have made a song and dance about it. The fact that they haven’t tells us that the C4 is no quieter and, in all probability, it is somewhat noisier. And clever and high-tech as the C4’s comms. system is, in terms of pure functionality, the C3 Pro’s still has some benefits."
Resolution: My lovely C4 went back to Schuberth in Germany - who changed out some internal padding & supplied a new PinLock insert. Better, but still noisy and unacceptable. Sadly it had to go back to Infinity for credit - thanks for your help with this Trevor & the crew @ Southampton! I tried a Shoei Neotec 2 - which was a really nice piece of kit, but in the end decided to buy a Schuberth C3 Pro - Echo Orange, with SC10U SRC Bluetooth Comms system (same as Kim uses). This is fab, like my C3 world, just better! I'm a happy (Easter?) bunny once more!