A pair of TS415 arrived a few days ago and I set about testing them. I have yet to use them in anger but in the meantime I have rattled the walls in my basement. The weight of the Alto is to my liking. Definately less wear and tear on my back, however, some may see the Alto as too light for a 15' speaker as it may affect their robustness - remains to be seen. The Alto has three handles for lifting and carrying the unit which I find very useful. The TS415 is well finished and looks good with a cool blue led at the bottom, which by the way, cannot be turned off.
I had previously been using a pair of Yamaha DXR12 and did a side by side comparison. The Yamaha has a 12" woofer while the TS415 obviously has a 15". The first thing I did was ignore the Alto 2500 watts claim. I see this as an almost meaningless number. The Yamahas are rated at 1100 watts but both speakers have a similar spl and sound equally loud as they reach their clipping points and they are both plenty loud! The Yamaha is slightly heavier but then again I have had them for a few years and they still crank the tunes and look good. There is no doubt the Alto produces noticably more bass with the mixer at the same settings which is to be expected from the 15" woofer. Pick the right track and you can feel the bass.
The bluetooth connection works well. I linked to an iphone then to a mixer via a bluetooth transmitter. There is no difference in the sound from the TS415 on bluetooth or hard wired. Linking the two units via bluetooth for stereo was simple and again works well. If for some reason you don't want to use speaker cables then the bluetooth connection is a solid alternative. The app provides control of the sound when using bluetooth. There are four settings, EQ off, Live, DJ and Custom. With the EQ off the speaker presents with a flat signal and sounds good. "Live" kills the bass and boosts the mids while the "DJ" setting boosts the bass and the highs. Custom allows the user to adjust one frequency and for me is not that useful. The app does allow the user to stand out front during a sound check to set volume and EQ settings.
Would I recommend the TS415, yes I would, especially for a DJ or a sound reinforcement setting. The bass is ample while the mids and highs are clear, not quite as clear as the Yamaha but it is only noticible when comparing the two side by side and even then only if one is being overly critical. If you use a sub in your set up then the Yamaha or something similar is your mark, perhaps even the Alto TS412. If you are using a speaker for vocals then I personally wouldn't go for the TS415. But if you are looking for a reasonably priced speaker with good bass for DJ work, give the TS415 a listen.