Apple invention appears to detail HomePod's adaptive acoustics

Posted:
in General Discussion edited July 2017
The U.S. Patent and Trademark Office on Thursday published an Apple patent application seemingly related to the company's upcoming HomePod speaker. In particular, the invention covers a method of equalizing and optimizing loudspeaker output through the use of microphones, digital signal processing and advanced computational algorithms.


Source: USPTO


In its patent application for a "Loudspeaker equalizer," Apple notes the positioning of a loudspeaker in a given room can have great effect on sound reproduction. For example, a speaker placed in the corner of a room might increase radiated acoustic power at low frequencies, causing bass-heavy sound.

Similarly, the position of a user respective to the speaker might negatively impact perceived frequency response.

To compensate for distortion and other effects, audio equipment manufacturers have long employed digital equalization techniques that optimize audio output.

For example, setup procedures of products like surround sound home entertainment systems utilize remote microphones to measure acoustic power radiated into a room from a variety of positions. Other systems incorporate internal microphones to monitor sound output and infer a global response, or the total acoustic power radiated into a room.

Microphone data is fed to internal circuitry like a processor and DSP, which filters or otherwise equalizes audio signals sent to the speaker drivers.

Apple's solution builds on prior global equalization solutions by employing multiple microphones located both inside and outside of a sealed speaker enclosure. In some embodiments, an internal microphone is positioned within the back volume of a speaker enclosure, or the cavity beneath a low frequency driver. A second microphone, or multiple microphones, located outside the speaker enclosure measure acoustic pressure in the vicinity of the driver.

Using onboard processing, the proposed system determines an equalization filter based on radiation impedance, a calculation derived from internal pressure levels, speaker displacement, external pressure and other measurement data provided by the microphone array. This filter is subsequently sent to the DSP for audio signal implementation.


Apple is promising similar acoustic technology from its HomePod device.


By comparing readings from internal and external microphones, Apple's loudspeaker system is capable of dynamically responding to its environment. More importantly, radiation impedance can be calculated in real time across a range of frequencies, allowing for constant sound optimization without prior calibration.

Other embodiments include two or more speakers that work together to monitor sound output. For example, the system can be made more efficient by allotting more power to loudspeakers which exhibit higher radiation resistance at certain frequencies.

Alternatively, the system might apply adaptive equalization filters such that the two or more speakers contribute the same acoustic power. This latter embodiment is preferable when a single speaker overpowers a second or third speaker because its radiation impedance is higher at specific frequencies.

Whether Apple intends to use today's invention in its upcoming HomePod speaker is unknown, though the company described similar technology in announcing the device last month.

Specifically, HomePod's A8 processor and at least six external microphones power acoustic modeling, audio beam-forming and multi-channel echo cancellation features for seven beam-forming tweeters and a central four-inch woofer. The device can automatically detect its surroundings and tailor audio output to match, Apple says. Further, when two HomePods are combined they automatically work together to provide room-filling sound.

Apple's loudspeaker equalizer patent application was first filed for in January 2016 and credits Sylvain J. Choisel, Martin E. Johnson and Jack Y. Dagdagan as its inventors.

Comments

  • Reply 1 of 18
    With no exaggeration, the Home Pod appears to be the best home speaker money can buy.
    watto_cobracornchip
  • Reply 2 of 18
    bill42bill42 Posts: 126member
    With no exaggeration, the Home Pod appears to be the best home speaker money can buy.
    Sadly at this size it will be lacking adequate bass to fill a decent sized room. Sonos and other competing sound systems with optional subwoofers will blow the audio quality of the HomePod out of the water. That being said I think the HomePod will surely be the best smart speaker that listens to and responds to voice commands with support for smart home systems. Perhaps that is what you meant to say.
    williamlondoncornchip
  • Reply 3 of 18
    ericthehalfbeeericthehalfbee Posts: 4,024member
    bill42 said:
    With no exaggeration, the Home Pod appears to be the best home speaker money can buy.
    Sadly at this size it will be lacking adequate bass to fill a decent sized room. Sonos and other competing sound systems with optional subwoofers will blow the audio quality of the HomePod out of the water. That being said I think the HomePod will surely be the best smart speaker that listens to and responds to voice commands with support for smart home systems. Perhaps that is what you meant to say.

    Sonos could never sound as good as they don't have the sophisticated room modelling or audio processing that the HomePod does.

    And why are you comparing Sonos with "optional subwoofers" to the HomePod? Why not compare a Sonos and HomePod directly?
    edited July 2017 StrangeDaysmacxpresswatto_cobrawilliamlondoncornchip
  • Reply 4 of 18
    robjnrobjn Posts: 203member
    bill42 said:
    With no exaggeration, the Home Pod appears to be the best home speaker money can buy.
    Sadly at this size it will be lacking adequate bass to fill a decent sized room. Sonos and other competing sound systems with optional subwoofers will blow the audio quality of the HomePod out of the water. That being said I think the HomePod will surely be the best smart speaker that listens to and responds to voice commands with support for smart home systems. Perhaps that is what you meant to say.
    Serious bass can be generated from a four inch woofer so long as it moves at the right frequency and generates sufficient pressure.

    Large speakers generate a more pressure since they have a bigger diaphragm surface area and they also tend to have a lower natural frequency.  You get a boomy sounding bass when you are listening to large enclosure resonate but this is not a true reproduction of the source.

    In this case Apple are generating a lot of pressure by means of high displacement. The combination of high displacement and a small back volume can result in high pressure = loud sound.

    There is an old myth that a speaker enclosure needs to be as big as the wavelength it is generating. Since bass frequencies might have a wavelength more than ten meters long - no speaker is big enough. The fact is that the back volume can be small and we don't want to listen to the resonance of the enclosure we want to listen to the resonance of the diaphragm.

    This patent shows that Apple have found a way to tightly control a driver by measuring and adjusting to external factors that effect the radiating impedance.

    It's going to be interesting to see a tear down of the HomePod. There might be more microphones than the six Apple has shown us. I'm curious as to whether each of the tweeters has an integrated microphone in the back or if this technique is applied only to the woofer.

    There is much more to HomePod DSP than this one patent covers. Those six external mics are being used to do a lot of different stuff!
    macxpresswatto_cobrapatchythepirate
  • Reply 5 of 18
    bill42bill42 Posts: 126member
    bill42 said:
    With no exaggeration, the Home Pod appears to be the best home speaker money can buy.
    Sadly at this size it will be lacking adequate bass to fill a decent sized room. Sonos and other competing sound systems with optional subwoofers will blow the audio quality of the HomePod out of the water. That being said I think the HomePod will surely be the best smart speaker that listens to and responds to voice commands with support for smart home systems. Perhaps that is what you meant to say.

    Sonos could never sound as good as they don't have the sophisticated room modelling or audio processing that the HomePod does.

    And why are you comparing Sonos with "optional subwoofers" to the HomePod? Why not compare a Sonos and HomePod directly?
    Simple reason: Because Apple doesn't yet offer a sub woofer or a larger speaker yet. All the sophisticated room modeling can't change the laws of physics that restricts the low frequencies you can get out of a small speaker. No doubt the high frequencies will be amazing. But without bass you will never get that live sound when playing your favorite song.
    williamlondon
  • Reply 6 of 18
    maestro64maestro64 Posts: 4,481member
     
    By comparing readings from internal and external microphones, Apple's loudspeaker system is capable of dynamically responding to its environment. More importantly, radiation impedance can be calculated in real time across a range of frequencies, allowing for constant sound optimization without prior calibration.

    This is fancy way of saying when you walk in from of the speak is will adjust the sound so your friend do not complain about blocking the speaker. Now only if they could do this for TV's and allow you to see when your friend walk in front of it.
  • Reply 7 of 18
    ericthehalfbeeericthehalfbee Posts: 4,024member
    bill42 said:
    bill42 said:
    With no exaggeration, the Home Pod appears to be the best home speaker money can buy.
    Sadly at this size it will be lacking adequate bass to fill a decent sized room. Sonos and other competing sound systems with optional subwoofers will blow the audio quality of the HomePod out of the water. That being said I think the HomePod will surely be the best smart speaker that listens to and responds to voice commands with support for smart home systems. Perhaps that is what you meant to say.

    Sonos could never sound as good as they don't have the sophisticated room modelling or audio processing that the HomePod does.

    And why are you comparing Sonos with "optional subwoofers" to the HomePod? Why not compare a Sonos and HomePod directly?
    Simple reason: Because Apple doesn't yet offer a sub woofer or a larger speaker yet. All the sophisticated room modeling can't change the laws of physics that restricts the low frequencies you can get out of a small speaker. No doubt the high frequencies will be amazing. But without bass you will never get that live sound when playing your favorite song.

    You're assuming people will use the HomePod in large rooms to play loud volumes. They won't. Just like all the millions of Sonos speakers used without a subwoofer.

    Anyone who wants that kind of sound isn't going to waste money on a lousy Sonos either, when there are lots of good speakers to choose from for that purpose.
    edited July 2017 williamlondoncornchip
  • Reply 8 of 18
    jcs2305jcs2305 Posts: 706member
    bill42 said:
    With no exaggeration, the Home Pod appears to be the best home speaker money can buy.
    Sadly at this size it will be lacking adequate bass to fill a decent sized room. Sonos and other competing sound systems with optional subwoofers will blow the audio quality of the HomePod out of the water. That being said I think the HomePod will surely be the best smart speaker that listens to and responds to voice commands with support for smart home systems. Perhaps that is what you meant to say.
      Sonos Play 3 with sub is $998.00 plus tax so I wouldn't necessarily call it a competing speaker with the addition of the sub. 

    Tech Radar and What Hifi give it decent reviews comparing it the Sonos Play 3 and the Amazon Echo.



    http://www.techradar.com/reviews/apple-homepod

    https://www.whathifi.com/apple/homepod/review

     


  • Reply 9 of 18
    bill42bill42 Posts: 126member

    robjn said:
    bill42 said:
    With no exaggeration, the Home Pod appears to be the best home speaker money can buy.
    Sadly at this size it will be lacking adequate bass to fill a decent sized room. Sonos and other competing sound systems with optional subwoofers will blow the audio quality of the HomePod out of the water. That being said I think the HomePod will surely be the best smart speaker that listens to and responds to voice commands with support for smart home systems. Perhaps that is what you meant to say.
    Serious bass can be generated from a four inch woofer so long as it moves at the right frequency and generates sufficient pressure.

    Large speakers generate a more pressure since they have a bigger diaphragm surface area and they also tend to have a lower natural frequency.  You get a boomy sounding bass when you are listening to large enclosure resonate but this is not a true reproduction of the source.

    In this case Apple are generating a lot of pressure by means of high displacement. The combination of high displacement and a small back volume can result in high pressure = loud sound.

    There is an old myth that a speaker enclosure needs to be as big as the wavelength it is generating. Since bass frequencies might have a wavelength more than ten meters long - no speaker is big enough. The fact is that the back volume can be small and we don't want to listen to the resonance of the enclosure we want to listen to the resonance of the diaphragm.

    This patent shows that Apple have found a way to tightly control a driver by measuring and adjusting to external factors that effect the radiating impedance.

    It's going to be interesting to see a tear down of the HomePod. There might be more microphones than the six Apple has shown us. I'm curious as to whether each of the tweeters has an integrated microphone in the back or if this technique is applied only to the woofer.

    There is much more to HomePod DSP than this one patent covers. Those six external mics are being used to do a lot of different stuff!
    robin: I am as excited as anybody to hear what Apple has created and I will buy one on preorder the day it goes on sale. You can indeed get some decent bass out of long throw woofers with long enclosures and I have some speakers like this but looking at the "woofer" in the apple speaker it looks like it will be loud as opposed to deep-sounding. I have a pair of tower speakers with multiple 8 inch woofers that reproduce live music pretty well, but even then I need my subwoofer to move enough air to reproduce the bass in hiphop music or the canons in the 1812 orchestra. The HomePod is going to be great for what it is but lets not even slightly entertain the idea that it will sound as good as dedicated high end audio speakers costing 10 times the price. It is being aimed at replacing the average small speaker system and in that realm it will surely succeed.
    williamlondon
  • Reply 10 of 18
    robjnrobjn Posts: 203member
    bill42 said:
    All the sophisticated room modeling can't change the laws of physics that restricts the low frequencies you can get out of a small speaker. 
    Please explain which laws of physics 'restrict low frequencies'.

    A 4 inch woofer with very high displacement can produce as much or more bass than an 8 inch woofer with low displacement. Woofers with larger surface area have the advantage of being able to work on a larger volume of air. Woofers with higher displacement can produce more intense pressure waves that radiate out. What we perceive as 'loudness' relates primarily to sound pressure levels. When a woofer with high displacement compresses it's back volume it generates high pressure and this results in loud bass.

    High displacement is harder to do because the woofer has to move further and faster, it's much easier to make a louder speaker by scaling up an easy and cheap design - this is what most manufacturers do - the easy thing.
    patchythepirate
  • Reply 11 of 18
    bill42 said:
    With no exaggeration, the Home Pod appears to be the best home speaker money can buy.
    Sadly at this size it will be lacking adequate bass to fill a decent sized room. 
    To some people's taste. For many people, room-pounding bass is not a desire, or even a positive.
  • Reply 12 of 18
    bill42bill42 Posts: 126member
    robjn said:
    bill42 said:
    All the sophisticated room modeling can't change the laws of physics that restricts the low frequencies you can get out of a small speaker. 
    Please explain which laws of physics 'restrict low frequencies'.

    A 4 inch woofer with very high displacement can produce as much or more bass than an 8 inch woofer with low displacement. Woofers with larger surface area have the advantage of being able to work on a larger volume of air. Woofers with higher displacement can produce more intense pressure waves that radiate out. What we perceive as 'loudness' relates primarily to sound pressure levels. When a woofer with high displacement compresses it's back volume it generates high pressure and this results in loud bass.

    High displacement is harder to do because the woofer has to move further and faster, it's much easier to make a louder speaker by scaling up an easy and cheap design - this is what most manufacturers do - the easy thing.
    What I meant was there are limits to how much displacement a 4 inch speaker can produce. There is a good audiophile thread going on right now on reddit discussing the Apple HopePod:  https://www.reddit.com/r/audiophile/comments/6ldl47/according_to_apple_the_ipod_reinvented_portable/

    Someone there claims the 4 inch woofer will move as much air as a typical 5.25 inch speaker but not as much as an 8 inch. This makes sense to me. the area of a 4 inch speaker is 12.57 square inches while an 8 inch speaker has an area of 50.27 sq inches. The speaker will sound amazing for its size but personally I would rather pay more for a larger one that had an 8 inch long throw woofer. However as many point out, this is not a speaker meant for a living room. It will probably sound great in a small bedroom or kitchen.
  • Reply 13 of 18
    foggyhillfoggyhill Posts: 4,767member
    bill42 said:

    robjn said:
    bill42 said:
    With no exaggeration, the Home Pod appears to be the best home speaker money can buy.
    Sadly at this size it will be lacking adequate bass to fill a decent sized room. Sonos and other competing sound systems with optional subwoofers will blow the audio quality of the HomePod out of the water. That being said I think the HomePod will surely be the best smart speaker that listens to and responds to voice commands with support for smart home systems. Perhaps that is what you meant to say.
    Serious bass can be generated from a four inch woofer so long as it moves at the right frequency and generates sufficient pressure.

    Large speakers generate a more pressure since they have a bigger diaphragm surface area and they also tend to have a lower natural frequency.  You get a boomy sounding bass when you are listening to large enclosure resonate but this is not a true reproduction of the source.

    In this case Apple are generating a lot of pressure by means of high displacement. The combination of high displacement and a small back volume can result in high pressure = loud sound.

    There is an old myth that a speaker enclosure needs to be as big as the wavelength it is generating. Since bass frequencies might have a wavelength more than ten meters long - no speaker is big enough. The fact is that the back volume can be small and we don't want to listen to the resonance of the enclosure we want to listen to the resonance of the diaphragm.

    This patent shows that Apple have found a way to tightly control a driver by measuring and adjusting to external factors that effect the radiating impedance.

    It's going to be interesting to see a tear down of the HomePod. There might be more microphones than the six Apple has shown us. I'm curious as to whether each of the tweeters has an integrated microphone in the back or if this technique is applied only to the woofer.

    There is much more to HomePod DSP than this one patent covers. Those six external mics are being used to do a lot of different stuff!
    robin: I am as excited as anybody to hear what Apple has created and I will buy one on preorder the day it goes on sale. You can indeed get some decent bass out of long throw woofers with long enclosures and I have some speakers like this but looking at the "woofer" in the apple speaker it looks like it will be loud as opposed to deep-sounding. I have a pair of tower speakers with multiple 8 inch woofers that reproduce live music pretty well, but even then I need my subwoofer to move enough air to reproduce the bass in hiphop music or the canons in the 1812 orchestra. The HomePod is going to be great for what it is but lets not even slightly entertain the idea that it will sound as good as dedicated high end audio speakers costing 10 times the price. It is being aimed at replacing the average small speaker system and in that realm it will surely succeed.
    Physics of cheapness you mean?
    It is more expensive to produce good bass in a smaller speaker, cause your driver needs to be more responsive and powerful (and more robust), but it is in no way needed.
    Your 8 incher is already small compared to the wave its producing, so why you think that's the "ideal" size anyway?

    Also, it doesn't need to be as good, it only needs to get to 95% of that 10 times more expensive speaker to blow to lid off Home audio.
    Considering those speakers don't really care about room acoustic generally and how poorly placed they are, just simplifying setup and ensuring good sound all around the room for most buyers would provide a much better experience than they're getting now from even more expensive speakers. You know, that "just works" mantra. Well, most stereo systems don't, "just work", in fact they're very very far from that now, which makes the field ripe for disruption.




    williamlondonpatchythepirate
  • Reply 14 of 18
    bill42bill42 Posts: 126member
    bill42 said:
    With no exaggeration, the Home Pod appears to be the best home speaker money can buy.
    Sadly at this size it will be lacking adequate bass to fill a decent sized room. 
    To some people's taste. For many people, room-pounding bass is not a desire, or even a positive.
    Who wouldn't want to hear a jazz song that sounds like alive band? You'll never hear an acoustic bass being strung without a good set of speakers.
    williamlondon
  • Reply 15 of 18
    bill42bill42 Posts: 126member
    foggyhill said:
    bill42 said:

    robjn said:
    bill42 said:
    With no exaggeration, the Home Pod appears to be the best home speaker money can buy.
    Sadly at this size it will be lacking adequate bass to fill a decent sized room. Sonos and other competing sound systems with optional subwoofers will blow the audio quality of the HomePod out of the water. That being said I think the HomePod will surely be the best smart speaker that listens to and responds to voice commands with support for smart home systems. Perhaps that is what you meant to say.
    Serious bass can be generated from a four inch woofer so long as it moves at the right frequency and generates sufficient pressure.

    Large speakers generate a more pressure since they have a bigger diaphragm surface area and they also tend to have a lower natural frequency.  You get a boomy sounding bass when you are listening to large enclosure resonate but this is not a true reproduction of the source.

    In this case Apple are generating a lot of pressure by means of high displacement. The combination of high displacement and a small back volume can result in high pressure = loud sound.

    There is an old myth that a speaker enclosure needs to be as big as the wavelength it is generating. Since bass frequencies might have a wavelength more than ten meters long - no speaker is big enough. The fact is that the back volume can be small and we don't want to listen to the resonance of the enclosure we want to listen to the resonance of the diaphragm.

    This patent shows that Apple have found a way to tightly control a driver by measuring and adjusting to external factors that effect the radiating impedance.

    It's going to be interesting to see a tear down of the HomePod. There might be more microphones than the six Apple has shown us. I'm curious as to whether each of the tweeters has an integrated microphone in the back or if this technique is applied only to the woofer.

    There is much more to HomePod DSP than this one patent covers. Those six external mics are being used to do a lot of different stuff!
    robin: I am as excited as anybody to hear what Apple has created and I will buy one on preorder the day it goes on sale. You can indeed get some decent bass out of long throw woofers with long enclosures and I have some speakers like this but looking at the "woofer" in the apple speaker it looks like it will be loud as opposed to deep-sounding. I have a pair of tower speakers with multiple 8 inch woofers that reproduce live music pretty well, but even then I need my subwoofer to move enough air to reproduce the bass in hiphop music or the canons in the 1812 orchestra. The HomePod is going to be great for what it is but lets not even slightly entertain the idea that it will sound as good as dedicated high end audio speakers costing 10 times the price. It is being aimed at replacing the average small speaker system and in that realm it will surely succeed.
    Physics of cheapness you mean?
    It is more expensive to produce good bass in a smaller speaker, cause your driver needs to be more responsive and powerful (and more robust), but it is in no way needed.
    Your 8 incher is already small compared to the wave its producing, so why you think that's the "ideal" size anyway?

    Also, it doesn't need to be as good, it only needs to get to 95% of that 10 times more expensive speaker to blow to lid off Home audio.
    Considering those speakers don't really care about room acoustic generally and how poorly placed they are, just simplifying setup and ensuring good sound all around the room for most buyers would provide a much better experience than they're getting now from even more expensive speakers. You know, that "just works" mantra. Well, most stereo systems don't, "just work", in fact they're very very far from that now, which makes the field ripe for disruption.




    Good point. The simple setup and the ability to sound good anywhere you put it is going to be what makes this a winner for Apple. Like the AirPods, people and the press will scoff at the expense compared to inferior competition, but soon enough word of mouth will drown out the naysayers. And we are talking abut audio quality only. With siri and an Apple TV on the same network, who knows what this thing might do? I for one will be an early adopter not even knowing what I will use the HomePod yet. I predict Apple will surprise us all. (Especially when it takes over the house and makes me a slave.)
  • Reply 16 of 18
    k2kwk2kw Posts: 1,699member
    bill42 said:
    With no exaggeration, the Home Pod appears to be the best home speaker money can buy.
    Sadly at this size it will be lacking adequate bass to fill a decent sized room. Sonos and other competing sound systems with optional subwoofers will blow the audio quality of the HomePod out of the water. That being said I think the HomePod will surely be the best smart speaker that listens to and responds to voice commands with support for smart home systems. Perhaps that is what you meant to say.
    Apple is probably redesigning AppleTV with the HomePods in mind. 

    And in future years Apple may decide to offer their own sub or allow third party subs to work via AirPlay 2.

    Its hard to tell who should be more worried, Sonos or Imagination Technologies.   Either way Sonos will probably lose sales as Apple grabs a share of the networked Audio Speaker market.

    I never bought a Sonos system myself because I wanted something that would integrated into and seemlessly support the Apple echo system.  now I'll get that from Apple ( or maybe one of the Airplay2 systems).
    williamlondon
  • Reply 17 of 18
    mattinozmattinoz Posts: 1,021member
    bill42 said:
    bill42 said:
    With no exaggeration, the Home Pod appears to be the best home speaker money can buy.
    Sadly at this size it will be lacking adequate bass to fill a decent sized room. Sonos and other competing sound systems with optional subwoofers will blow the audio quality of the HomePod out of the water. That being said I think the HomePod will surely be the best smart speaker that listens to and responds to voice commands with support for smart home systems. Perhaps that is what you meant to say.

    Sonos could never sound as good as they don't have the sophisticated room modelling or audio processing that the HomePod does.

    And why are you comparing Sonos with "optional subwoofers" to the HomePod? Why not compare a Sonos and HomePod directly?
    Simple reason: Because Apple doesn't yet offer a sub woofer or a larger speaker yet. All the sophisticated room modeling can't change the laws of physics that restricts the low frequencies you can get out of a small speaker. No doubt the high frequencies will be amazing. But without bass you will never get that live sound when playing your favorite song.
    With Airplay2 do Apple need to make a sub themselves or just let others make them as up sell?

  • Reply 18 of 18
    foggyhillfoggyhill Posts: 4,767member
    bill42 said:
    foggyhill said:
    bill42 said:

    robjn said:
    bill42 said:
    With no exaggeration, the Home Pod appears to be the best home speaker money can buy.
    Sadly at this size it will be lacking adequate bass to fill a decent sized room. Sonos and other competing sound systems with optional subwoofers will blow the audio quality of the HomePod out of the water. That being said I think the HomePod will surely be the best smart speaker that listens to and responds to voice commands with support for smart home systems. Perhaps that is what you meant to say.
    Serious bass can be generated from a four inch woofer so long as it moves at the right frequency and generates sufficient pressure.

    Large speakers generate a more pressure since they have a bigger diaphragm surface area and they also tend to have a lower natural frequency.  You get a boomy sounding bass when you are listening to large enclosure resonate but this is not a true reproduction of the source.

    In this case Apple are generating a lot of pressure by means of high displacement. The combination of high displacement and a small back volume can result in high pressure = loud sound.

    There is an old myth that a speaker enclosure needs to be as big as the wavelength it is generating. Since bass frequencies might have a wavelength more than ten meters long - no speaker is big enough. The fact is that the back volume can be small and we don't want to listen to the resonance of the enclosure we want to listen to the resonance of the diaphragm.

    This patent shows that Apple have found a way to tightly control a driver by measuring and adjusting to external factors that effect the radiating impedance.

    It's going to be interesting to see a tear down of the HomePod. There might be more microphones than the six Apple has shown us. I'm curious as to whether each of the tweeters has an integrated microphone in the back or if this technique is applied only to the woofer.

    There is much more to HomePod DSP than this one patent covers. Those six external mics are being used to do a lot of different stuff!
    robin: I am as excited as anybody to hear what Apple has created and I will buy one on preorder the day it goes on sale. You can indeed get some decent bass out of long throw woofers with long enclosures and I have some speakers like this but looking at the "woofer" in the apple speaker it looks like it will be loud as opposed to deep-sounding. I have a pair of tower speakers with multiple 8 inch woofers that reproduce live music pretty well, but even then I need my subwoofer to move enough air to reproduce the bass in hiphop music or the canons in the 1812 orchestra. The HomePod is going to be great for what it is but lets not even slightly entertain the idea that it will sound as good as dedicated high end audio speakers costing 10 times the price. It is being aimed at replacing the average small speaker system and in that realm it will surely succeed.
    Physics of cheapness you mean?
    It is more expensive to produce good bass in a smaller speaker, cause your driver needs to be more responsive and powerful (and more robust), but it is in no way needed.
    Your 8 incher is already small compared to the wave its producing, so why you think that's the "ideal" size anyway?

    Also, it doesn't need to be as good, it only needs to get to 95% of that 10 times more expensive speaker to blow to lid off Home audio.
    Considering those speakers don't really care about room acoustic generally and how poorly placed they are, just simplifying setup and ensuring good sound all around the room for most buyers would provide a much better experience than they're getting now from even more expensive speakers. You know, that "just works" mantra. Well, most stereo systems don't, "just work", in fact they're very very far from that now, which makes the field ripe for disruption.




    Good point. The simple setup and the ability to sound good anywhere you put it is going to be what makes this a winner for Apple. Like the AirPods, people and the press will scoff at the expense compared to inferior competition, but soon enough word of mouth will drown out the naysayers. And we are talking abut audio quality only. With siri and an Apple TV on the same network, who knows what this thing might do? I for one will be an early adopter not even knowing what I will use the HomePod yet. I predict Apple will surprise us all. (Especially when it takes over the house and makes me a slave.)
    In theory it could not just adapt to the room, or type of music but also to the people's position. Coordination with other speakers it could create standing waves and interference patterns so the sound is heard loudly just in one spot you choose and nowhere else.  mapping the room and an ability to project sound at will also has implications for augmented reality thst few seemingly have noticed. 

    With the the phone and pod, the user could not only reproduce something visually but also reproduce a soundscape
    mattinoz
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