Siri now has a dedicated smart speaker to call home, so it's time to consider how Apple's voice assi

Let's explore the obvious -- as well as more nuanced -- differences between these voice AIs. By the end of it, we'll have a better sense of each assistant's strengths, as well as where they need the most work.

Recognizing your voice
Connect your call to a HomePod via the audio button.]]>
On the HomePod, unlike the iPhone, Siri can't differentiate between voices. That means anyone who says "Hey, Siri" will elicit a response from the Apple smart speaker. In contrast, both Amazon and Google smart speakers have voice training capabilities. With voice training, your whole family can use the speakers, but each of you can also get customize responses (and perform custom actions, like making purchases) based on who the speaker is talking to.

The HomePod simply doesn't provide that depth of personalization. That said, Google and Amazon haven't completely nailed the feature. During testing, we were able to trick Alexa and Google Assistant by pretending to be our coworkers.

Making calls
If I say "Hey Siri, call Tyler Lizenby" (CNET multimedia producer) on my iPhone, she responds, "Calling Tyler Lizenby, mobile." If I give HomePod the exact same command, she'll reply: "I wish I could, but I can't help you make calls on HomePod." Bummer. Yep, Siri (on HomePod) doesn't let you dial in or out. Instead, the HomePod acts as a speakerphone. Either dial or receive a call on your iPhone and use the Audio button on the call screen to transfer the audio to your Apple speaker (see screenshot).

Alexa- and Google-Assistant-enabled speakers work differently. Both can currently dial out with simple voice commands. On Alexa, you can only receive calls from other Echo speakers; cell and landline calls are not supported. Google Assistant can't receive calls.

Unlike calling, you can send messages from HomePod, as well as from Alexa and Google Assistant.

Music services
Amazon and Google support a wide range of third-party music services, so your Alexa or Google Assistant speaker can play a Spotify song with a simple voice command.

Siri on the HomePod isn't able to do this. You can only use voice commands to play Apple-approved music services. So, if you want to use Spotify, YouTube or another third-party service, you can, but you have to send the song manually from your phone or other iOS device (or on Windows PCs running iTunes) via Apple's Airplay service.

Here's more info on approved music services for Siri (on HomePod), Alexa (on Echo speakers) and Google Assistant (on Home speakers).

General questions
Siri actually did a great job responding to my basic, everyday questions, roughly the same as using Alexa or Google Assistant. If I wanted to know the weather forecast, the at-a-glance driving time to a movie theater across town, the name of some local restaurants that deliver, the latest news updates or information about a song playing on HomePod, the Apple voice assistant worked very well.

We ask Siri, Alexa and Google Assistant the same three questions
Siri also did a pretty good job with follow-up questions and natural language. For example, asking something like, "Tell me about the band Metallica" I could follow up with a question like, "How old is their drummer?" without repeating any reference to Metallica. Google Assistant also successfully responded to a variety of natural language questions; Alexa wasn't quite as responsive when it came to conversational follow-up questions.

Certain questions confused Siri on the HomePod, though. When we asked her, "Who is the senior senator of Kentucky?" Siri said, "I can't get the answer to that on HomePod." Ask Siri the same question on an iPhone and she'll produce the relevant Wikipedia link, so she can do the work, she just can't describe her findings yet. But if you ask Siri, "Who is Mitch McConnell?" she answers. Alexa and Google Assistant had no problem answering either question, and with their voices.

Expanding from the senior Kentucky senator question to other basic queries was hit-or-miss for Siri. Some she answered immediately, others she couldn't answer at all.

Siri's listening when you see this glowing display. ]]>
Smart home
I'm conflicted about using "Hey, Siri" on the HomePod to control smart home devices. During the HomePod set up, all of the info about your local Wi-Fi network, contacts and preferences are automatically sent over to the HomePod. That includes any existing HomeKit products you have set up on your iOS device. It's ridiculously simple.

And every smart-home integration is so closely regulated by Apple that using voice control to open smart shades, adjust a thermostat or turn on lights is easy to achieve with a basic "Hey, Siri" command, because Apple supports all of those device types directly. In contrast, both Alexa and Google Assistant give you "invocation" words to interact with device types they don't support out of the box, such as, "Alexa, ask Geneva when the dishwasher will be finished." Alexa doesn't have built-in support for dishwasher commands yet, but it at least lets device partners engineer a workaround. Up to this point, Apple has managed to avoid using those more clunky phrases simply by not offering those partnerships. It ensures a more streamlined user experience, but across a more limited set of devices.

The winner?
While Siri has improved in terms of her ability to process and respond to natural language, she still has some ground to cover to match the depth and breadth of Alexa and Google Assistant. I like the seamlessness of "Hey, Siri" for controlling HomeKit devices versus the invocation words you occasionally have to use to manage/control Alexa- and Google-Assistant-enabled products. But, again, Apple has far fewer third-party smart-home partners than either of its competitors. I'd like to see her become more capable at speaking out loud her findings from around the Web.

When Apple officially drops its MFi (made for iPhone/iPad/iPod) requirement for HomeKit devices, its limited list of compatible products will likely grow. But we won't know for sure until iOS 11.3 launches the spring. In the meantime, I expect Alexa to maintain its smart speaker dominance for the foreseeable future.