Here's a quick rundown on what's new and improved over the first gen SLC (in no particular order):
IPX4-rated water-splash resistant (*not* immersible/submersible)
NFC enabled Bluetooth pairing (just enable NFC & BT, then tap to pair)
Speaker phone functionality over Bluetooth, with call controls located on the SLCII
Other notable facts:
The built-in Lithium-ion battery is still not user replaceable.
The SLCII's radio for music/speakerphone is still strictly Bluetooth (no WiFi).
Two SLCIIs cannot be Bluetooth paired for wide-field stereo (although this could be accomplished with a *custom* made line-in stereo-stereoR-stereoL splitter cable - where all three plugs have to be three-element stereo).
According to BOSE Tech Support, the SLCII is a true stereo speaker. with two, closely spaced, 40mm active drivers, one each for left and right channels. They are so close together, though, that you'd have to be very, very close (~6") to the SLCII to notice the stereo effect.
My intention is to primarily use the SLCII as the main external speaker for a powerful, yet tiny, portable AM/FM/WX/AIR/SW radio receiver that is replacing a much larger, luggable, 30 year old, rugged, workhorse multi-band radio that finally gave up the ghost. The tiny portable isn't Bluetooth capable and only has a built-in 1.5" speaker and 3.5mm line-out. That 1.5" speaker performs amazingly well, for its size, but has all of the acoustic limitations that one must expect from a speaker that size. (The radio sounds unbelievably good using quality earbuds.) Using a 3.5mm, male-male, standard stereo cable between them, the SLCII is a perfect match for both voice and music programs, creating a room filling table radio sound.
That said, the equalization of the SLCII is *not* aimed at high fidelity sound reproduction. The default EQ seriously over-emphasizes the bass, sloppily booming way too much ~150Hz, with complete roll-off somewhere above 60Hz. This is true whether using Bluetooth or 3.5mm cables, no matter how the unit is physically placed (for bass reflectivity). There are some EQ differences in the upper/mid ranges; Bluetooth sounds brighter than hardwired, using the same source devices, playing the same content examples in Bluetooth vs line-in testing.
One thing that BOSE should seriously consider is a firmware update to the SLCII that programs the amp to produce a flatter frequency response curve from the SLCII when using the line-in connection. There is no reason to treat line-in on the SLCII the same as Bluetooth, specifically because of the ongoing limitations with Bluetooth audio codecs. For line-in, a flatter frequency response in the SLCII is to be highly preferred.
Fortunately, I have very good music players on my various Android devices that enable me to adequately compensate for the SLCII's weird EQ, so that, for indoor listening, a high degree of acoustic fidelity can be teased out of the SLCII, period, not just good sound "for its size."
The EQ shipping on the SLCII is most likely optimized for outdoor use; but, outdoors, the SLCII is going to face many limitations based entirely on its size.
- Battery and Charging issues
I knew that the unit would ship with only a partial charge (30% as required by law), but I was surprised at how erratically my first SLCII announced that it had reached a full charge.
If I had to guess, based on BOSE's stated cycle life of 300 deep discharges before battery failure and the prohibition in the full PDF user manual (p 21) against long term storage of the SLCII with a fresh full charge (indicating, to me, heightened thermal instability at full charge), I'd infer that BOSE put a Lithium Manganese Oxide (LiMN2O4) battery inside the SLCII. If I had a say in the matter, I would prefer a Lithium Titanate (LiTi5012) battery, because it can survive >3000 deep discharges and is highly thermally stable at all states of charge.
The first thing I did after examining the SLCII for any possible shipping damage was to plug it into to a 2.0A USB charger. I was very surprised to suddenly hear the SLCII announce that it had reached a full charge (with a steady green LED light) after only 20 minutes of charging. I suspected that something might be very wrong.
It turned out that my hunch was right. The first SLCII charged erratically, pre-maturely reporting full charge. Eventually, it failed to power on or charge, at all, and even resisted an undocumented BOSE "hard reset." Fortunately, BOSE dispatched a replacement.
Wildly varying recovery charge times simply should not be observed immediately after a supposed full charge of any properly working battery, Lithium ion or not.
The useful calendar lifespan of consumer electronics Lithium-ion batteries really benefits from keeping the battery's charge above 50% of the originally rated total mAH capacity. If one can't reliably know that a battery is, indeed, "fully charged," then there is no way to even begin to guess about where 50% of a full charge might be.
Routinely deeply discharging, or discharging below 50% of a factory-rated full charge, will dramatically shorten the calendar life of a consumer electronics Lithium-ion battery. This is where the 300 charge cycle calendar life controversy with the original SLC comes from. Keep the Lithium-ion topped up as much as possible. On the other hand, a Lithium Titanate battery would be good for at least 1000 full charge cycles. It seems cynical, to me, for BOSE to knowingly use a 300 cycle battery on a one year warranty product.
It would be also very nice if the SLCII would give visual/audible notice that it has discharged to 50% of original capacity, so that people will know when to plug back into external power, should they care about maximizing their battery calendar life. It's potentially the difference between 300 full cycles and 500 or more top-off charges.
Non-user-replaceable batteries and battery calendar life were problems with the original SLC.
The replacement SLCII sent to me took just under two hours of out-of-the-box charging to report its first full charge. After 10 minutes off charger, doing nothing, the SLCII then took 9 minutes back on charger to report a full charge. Another 10 minutes off charger, then 5 minutes back on charger to report a full charge. Finally, another 10 minutes off charger, then only 1 minute back on charger to report a full charge. This pattern satisfies me that the battery and charging circuitry are AOK in the replacement SLCII. Once again, the replacement SLCII never got warmer than ambient room temperature during any of these charging tests (as measured with an IR temp gun). If your SLCII gets hot during charging, that is likely another sign of battery problems to come.
- Bluetooth pairing
I had no need to use the BOSE Connect app for Bluetooth pairing.
Standard Bluetooth pairing worked with all of my Android devices and the SLCII.
Deleting all previous SLCII pairings, NFC Bluetooth pairing also worked with all my NFC-capable Android devices, but sometimes it took more than one tap and/or twist to find the NFC sweet spot on each Android device. Nevertheless, NFC Bluetooth pairing always worked for me.
- Speaker phone capability
I don't plan on using this feature much, if at all, but a lot of people asked for it. I prefer to use wired headsets for privacy and confidentiality. Should I get around to testing speaker phone capability, I will add a comment to this main review.
I assume that the SLCII behaves exactly like a Bluetooth headset when it comes to making and receiving speaker phone calls. Via the multifunction button on the SLCII, there is call control on the device, too.
BOSE Tech Support could not tell me whether or not the speaker phone capability of the SLCII is full-duplex or half-duplex. This matters a lot in situations where there is a lot of ambient background noise on either end of a call, especially outdoors.
- Bottom Line on the BOSE SoundLink Color II
For what I am going to mostly use it for, the SLCII sounds dramatically better than the much larger integrated, luggable device that it is replacing, given what I've written above, at far less than half the size and less than a quarter of the total weight.
The SLCII does not seem to be intended to be a high-fidelity music/sound reproduction device, but I personally also find that to be the case for the entire BOSE SoundLink product line. I've auditioned them all, indoors, with my sound source devices and content, and I hear differently distorting EQ with ALL of them. The SoundLink III and SoundLink Mini do have more stereo separation. The SLCII (and the entire SoundLink line) is engineered to deliver sound with DYNAMIC PRESENCE, not high fidelity. As such, the SLCII is more like an instrument unto itself, rather than purely a sound reproduction device. If you insist on high-fidelity sound reproduction, you'll have to look somewhere other than the BOSE SoundLink for the time being.
As an external speaker for Android devices, given my ability to tweak player equalization on the Android side, the SLCII is a remarkably good sounding portable powered speaker. The IPX4 splash rating is welcomed. NFC Bluetooth pairing just works according to the simple instructions.
If BOSE makes firmware updates available for the SLCII, and if the BOSE Connect app can apply said firmware update to the SLCII, then I may have a use for the app. But I have seen no firmware updates for the SLCII, to date.
Despite the fixable issues with charging and battery management, I still recommend the SLCII to others looking for a highly portable, multi-function, external speaker for music and/or voice reproduction.