Maybe frequency response won't tell you how tight the bass is but it will definitely tell you if there is any bass or not. And with HomePod we are not past this point yet. And I am pretty sure that with 4.5" woofer and the size of this speaker the bass will be lousy.
And you are fooling yourself if you think HomePod has the low frequencies anywhere near the examples you gave. You'll be lucky if you get 100Hz.
You’re all over the place with your comments, changing your position with each rebuttal. Let’s take this most recent comment about bass to show you how wrong you are.
First off the 100Hz comment is absolutely false. I’ve always used PSB Speakers, so I looked at their current offerings. They have a bookshelf called the Imagine mini. It has a 4” bass and 1” tweeter. Its frequency response is rated at 55-23,000 Hz +/- 3dB. It’s also a multiple award winner.
http://www.psbspeakers.com/products/bookshelf-speakers/Imagine-mini
See that bottom number? 55Hz. So much for 4” drivers not being able to produce anything below 100Hz. And this was literally the first speaker I found with a 4” driver.
I’m convinced the HomePod will not only go lower still, but will have greater output. First off, refer to the attached picture of a typical bass driver.
Speaker operation is pretty basic. You pass an electrical current (audio) through the voice coil which creates an electromagnetic field. Since the voice coil is located within a circular permanent magnet, it will move forward or backward in response to this electrical current.
In order for the voice coil to move it has to overcome three opposing forces. The most obvious one is air - to produce bass you need to move air and this requires energy. The other two are the spider and the surround.
Speaker designers always make decisions (trade-offs) in the construction of the spider and surround. If they are very flexible and easy to move then the speaker is more efficient. For a given amount of energy passed through the voice coil, less is required to overcome the physical resistance of the spider and surround which leaves more energy to actually move the air. If they are very stiff, then it requires greater energy to overcome the spider and surround, leaving less available to move air. The speaker is less efficient.
Now you might wonder why someone would make a speaker with a stiffer spider/surround, if it makes the speaker less efficient. The problem with a highly flexible suspension is that the speaker tends to be “sloppy”. Without any resistance it moves so easily that it can “overshoot” where it’s supposed to move to before being driven back in the opposite direction. This results in muddy/sloppy bass. A stiffer suspension does the opposite - the bass will be tighter and well controlled.
One method engineers do to tighten up the bass is to use a speaker with a flexible suspension, but put it into a sealed enclosure. In order for the speaker to move it now has to overcome the air pressure within the enclosure. However, this again reduces efficiency. These are the decisions engineers have to think about when designing speakers. Nothing is free and there are always tradeoffs.
Enter the HomePod. It has a very high excursion bass driver. It also has no enclosure. If it has a stiff suspension it will be inefficient. If it has a flexible suspension then the bass will be sloppy. Or will it?
The HomePod has one unique feature that’s not talked about much. It has a single dedicated microphone whose sole purpose is to monitor the movement of the bass driver and make real-time corrections. This is why I think the HomePod bass driver has a flexible suspension to allow for higher efficiency and greater bass output. The microphone is used to make sure the bass isn’t sloppy by correcting the driver movements. So you get a flexible suspension AND tighter more controlled bass.
Will it rock your house like a 12” subwoofer? Of course not. But it will have pretty damn good bass for it’s size, and will most certainly go well below your claim of 100Hz.