lorin schultz

tmay said:
I would note that even the detractors of that specific test haven't figured out how Apple is both analyzing the room and creating the speaker outputs beam forming and levels for that.

It's certainly possible that whatever voodoo Apple do with the HomePod confused the analyzer and caused it to report incorrect data.

It's also possible that the room correction feature of the HomePod just doesn't work very well.

Based on what we know about the physics of sound and what we've been able to accomplish in reproduction systems over the last century I'm inclined to suspect it's the latter, but I'm keeping an open mind.

dick applebaum said:

1. people don't listen to music in an anechoic chamber

Absolutely true. However, since room boundaries affect the frequency response of a speaker in ways that are impossible for the designer to control, anechoic testing is an objective means of evaluating what the speaker is CAPABLE of doing. Plotting a response graph in situ makes it impossible to determine whether response deviations arise from a deficiency in the speaker or are caused by standing waves. Removing the reflections by testing in an anechoic chamber overcomes that.

What complicates this particular case is Apple's claim that the HomePod automatically adjusts for room acoustics. If that's the case, then it should not be necessary to test the HomePod in anechoic conditions. If room nodes/standing waves are causing reinforcement of some frequencies and attenuation of others, the HomePod should be adjusting for and correcting that. Clearly, based on the response graph posted by the reviewer, it's not.

That means both the reviewer AND his critics are wrong. The frequency response of the HomePod is not flat, and the testing methodology was not inherently flawed.

RedditAudiophile said:

--UPDATE--

Please read the EDIT portion of the review:

https://www.reddit.com/r/audiophile/comments/7wwtqy/apple_homepod_the_audiophile_perspective/

Tl;Dr:

I am speechless. The HomePod actually sounds better than the KEF X300A. If you’re new to the Audiophile world, KEF is a very well respected and much loved speaker company. I actually deleted my very first measurements and re-checked everything because they were so good, I thought I’d made an error. Apple has managed to extract peak performance from a pint sized speaker, a feat that deserves a standing ovation. The HomePod is 100% an Audiophile grade Speaker.

EDIT: before you read any further, please read /u/edechamps excellent reply to this post and then read this excellent discussion between him and /u/Ilkless about measuring, conventions, some of the mistakes I've made, and how the data should be interpreted. His conclusion, if I'm reading it right, is that these measurements are largely inconclusive, since the measurements were not done in an anechoic chamber. Since I dont have one of those handy, these measurements should be taken with a brick of salt. I still hope that some of the information in here, the discussion, the guesses, and more are useful to everyone. This really is a new type of speaker (again see the discussion) and evaluating it accurately is bloody difficult.

I haven't yet had time to read the full exchange in detail, but I have a couple observations based on the skimming I've done so far:

1. I've been politely hinting that the graph provided by the reviewer contradicted his assertion of flat response. It is decidedly NOT flat, and shows particularly broad swings from the low mids on down. The variations at the lower end of the scale are usually -- not always and not necessarily, but usually -- indicative of room nodes causing waves to cancel and reinforce at certain frequencies. This ties in to the second point:

2. It's true that speakers are traditionally measured in anechoic chambers exactly because room reflections cause the kind of problems we see in this test, and the results will vary not only from room-to-room, but from one position to another in the same room. HOWEVER, Apple has made a lot of noise about the automatic room correction the HomePod is supposed to perform. That means in the case of the HomePod -- not necessarily any other speaker, but specifically the HomePod -- it's fair and reasonable to conduct frequency response testing in ANY space, anechoic or not. Apple claims the HomePod will automatically adjust itself to compensate for room acoustics. If it does, then an anechoic chamber should not be required. If the gross non-linearity we saw in the reviewer's test actually is the result of room nodes, then HomePod's automatic room correction apparently doesn't work very well.

Neither of these points are meant to demean the HomePod in any way. By all accounts it sounds better than it costs. The fact that it isn't a studio monitor-grade performer doesn't mean it can't be an excellent value and thoroughly enjoyable. It just isn't the paradigm shifting revolution the marketing implied it would be.

tmay said:

I kind of expect some audiophiles to reverse engineer for Apple's algorithms and create a set of rules to optimize HomePod placement.

Which, of course, is utterly contrary to Apple's claim that one of the primary features of the HomePod is its being placement agnostic!

I think you're right that audiophiles will create placement optimization guidelines, but not based on any reverse engineering. They will come from purely subjective "listening tests" with no controls on variables. From these will arise explanations for the results, such as the skin effect being minimized in internal wiring when the orientation aligns with Earth's poles.

rain22 said:

timmillea said:

What a way to test sound quality - heavily compressed studio mush! Live-recorded orchestral or jazz would have been a better testing candidate

Agreed. I would have also liked to have heard something from Tidal MQA - to see which handles it better. AM’s low quality AAC compression is the target audience thou. But yah, those 2 songs were brutal

The problem with pop music for comparisons is that there's so much dynamic range compression that it's impossible to know whether the pumping we're hearing is indicative of a deficient amp or just the way the song sounds.

I'm not terribly concerned about using AAC files for this kind of thing though. The difference between a well-encoded 256Kb AAC and straight PCM is pretty subtle these days, and is utterly swamped by MUCH more significant anomalies on gear in this range. I seriously doubt most of us could even reliably tell the difference between AAC and PCM in a blind comparison using any of those speakers.