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Old February 19th 18, 12:38 PM posted to
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Posts: 10
Default Apple HomePod measurements

On 2018-02-15, ~misfit~ > wrote:
> Once upon a time on usenet -dsr- wrote:
>> I cannot vouch for the accuracy of these measurements, since
>> I had no part in them. I am just relaying this article to
>> you since it might well be interesting.
>> TL;DR: Room correction forces a rather small speaker
>> "All the way from 40Hz to 20,000Hz it's ±3dB,
>> and from 60Hz to 13.5Khz, it's less than ±1dB"
>> -dsr-

> Interesting, thanks.

And rather more interesting:

TL;DR: I'll quote a chunk from the middle:

------ quote begins

This paragraph is grossly misleading:

What we can immediately see is that the HomePod has an incredibly
flat frequency response at multiple volumes. It doesn’t try to
over emphasize the lows, mids, or highs. This is both ideal, and
impressive because it allows the HomePod to accurately reproduce audio
that’s sent to it. All the way from 40Hz to 20,000Hz it's ±3dB,
and from 60Hz to 13.5Khz, it's less than ±1dB... Hold on while I
pick my jaw up off the floor.

At first glance it looks like this is about the frequency response of the
speaker, and indeed if it was, these would be impressive numbers. It's
not, though. It's about deviation from linearity, which has to do mostly
with power compression and DSP limiting. It has nothing to do with
frequency response, which is a much, much more important metric. The way
that passage is worded is so mind-bogglingly misleading that I'm having
a hard time believing it was not written that way on purpose.

While I agree with the experimenter that the bass performance of the
speaker looks interesting considering its small size, there's some
misleading stuff in there too. When the experimenter writes "Apple's
got the HomePod competently producing bass down to ~40 Hz, even at 95
dB volumes", that does not mean that the HomePod can produce 95 dB at
40 Hz, which would indeed by extremely impressive for its size. Instead,
the linked measurement shows that the HomePod will limit itself to less
than ~80 dB at low frequencies. Now the automatic distortion control
is interesting perhaps, but still, there's no magic here. (A proper
subwoofer can go to 100+ dB at these frequencies, but it's also much
larger in size.)

The experimenter mentions that the speaker is capable of room
correction. It's not. Proper room correction systems can get frequency
response variations down to ±2 dB or less - that's not hard to achieve
as it's mostly just about inverting the room response. The experimenter's
own measurements, when viewed at the proper scale, show that the HomePod
doesn't do any better than the KEF or any other speaker in that regard.

------ end quote.