Amazon Echo 4 - Teardown and few measurements

[trl]

Hello all,

Just got a week ago an Echo 4 and today I decided to measure it's audio capabilities and also to see what's inside its spherical case.

On the bottom we can see its 30W power requirements (18V/1.6A), S/N#, Model no. and the fact that it includes a Zigbee hub inside as well.
Under the rubber circle I've pealed off we can see the four screws that keep the bottom plate tighten.​

The white ring is a light diffuser to properly spread LED's light around the sphere, for a better visibility.​

I can count 24 LEDs, all of them being RGB.​

There are couple of LP5036 LED drivers that control the 24 RGB lights according to the right scenario Alexa is performing​

The two speakers amplifiers are encapsulated in the metallic shield, either for not being easy to disclose, either for RFI shielding.
I do like to see there are polymer caps inside and that are all properly glued on the PCB, so bass vibrations will not affect the soldering during time.

The metallic plate from the bottom of the case is also used as a heatsink, so the two speakers amplifiers are getting their heat transferred on this heatsink via the pinkish thermal adhesive tape.

Looks like most of the chips are hidden under the metallic shields, so it will be rather impossible to see what's inside, unless someone will use a heat gun to unsolder these shields (I'm not going to do it due to the warranty and due to the high risk of damaging nearby components).

We can spot a low-noise quad op-amp TL974, few other shielded chips and few grounding pins that grounds the metallic heatsink plate to the PCB.

The metallic pins (springs) I that grounds the heatsink to PCB's GND.

3.0" woofer (paper) and dual front-firing 0.8" tweeters (silk?)

Close-up with the 3" woofer

For unknown reason the woofer has three connection pins, although I only have DC resistance only between two of them (3.7 Ohms).
Worth mentioning that the tweeters have 7.8 Ohms each.

I simply couldn't resist not to cover the inner holes of the woofer with a piece of sound damping stuff, to minimize some of the internal vibrations. ​

 

[trl]

I was using my Motu M4 studio interface and the ECM999 measurement microphone for the following tests. As software I used REW and ARTA. Mic was pointing at the speaker at an approximate 30 degrees, from above, in all measurements (unless specified different).

Echo 4 - on the same graph we compare 40% level output vs. 70% level output.
​

Echo 4 has some sort of internal loudness control, so when volume is low the bass increases, and when volume increases the bass is decreasing a bit. I personally found levels between 4 and 7 having a rather lower THD, while increasing the volume above 8 out of 10 levels will increase the THD and compress the output sound as well.

Echo 4 - on the same graph we compare No EQ output vs. Bass to 6 (max.).​

Echo 4 - on the same graph we compare No EQ output vs. Midrange to 6 (max.).​

Echo 4 - on the same graph we compare No EQ output vs. Treble to 6 (max.).​

Echo 4 - on the same graph we compare how devices sounds 30 degrees above vs. 0 degrees (perpendicular)​

As we can see from the above graph, Echo 4 was designed to spread sound very well on the upper side, so placing it on a table or bottom shelf would be beneficial to the sound. Placing Echo 4 on a shelf higher than 1 m will decrease sound quality a lot, given that tweeters are having quite a narrow dispersion angle and the midrange will probably be greatly impacted too (woofer is firing the midrange on top of it).

Looks like starting 120 Hz the distance between the fundamental and distortions gets higher than 50 dB, that being the same with all levels between 40% and 70% (actually at 80% is pretty much the same too)

0.96 % THD @1 kHz sine

A bit over 2% THD @100 Hz sine

A bit less than 2% THD @10 kHz sine

A bit more than 3% THD @16 kHz sine

IMD @60 Hz and 7 kHz

Bluetooth from my iPhone, audiocheck.net 1 kHz sinewave, 0.96% THD+N, pretty close to what I got when I was feeding Echo 4 via the analogue input jack

​

I had pretty low expectations from this Echo 4, but after few days of listening, given its low price (69 EUR @ Black Friday) and the fact that it was not designed as a small Hi-Fi speaker, but more as an Alexa compatible device, I now think it's quite usable in a bedroom or even in a living room. I personally use it in a 25m2 living room with Tidal playing at 40-50% of volume (that means levels 4 to 5) and get a pleasant audition that fills the room well.

The sound of Echo 4 is a bit on the dark side, so I use Trebles +3 and Mids +1, which I recommend you to try out if you're using already such a speaker. After 80% of volume the sound gets compressed and bass starts to lack, while distortions increases too.

On the jack-out, at 80% output volume, it gets about 0.9V RMS, which is rather low. After 80% of output volume the THD is too high to worth measuring here on ASR.

 

[MachOne]

Love a good teardown. If you look on the inside of the woofer with a flashlight you should be able to see if the third woofer terminal goes anywhere.

 

[trl]

I initially thought there are two 2 Ohms coils serialized inside, but it looks it's not, so I'm puzzled why the three pins are there connected and wired.

However, here's an extraordinary teardown of the Echo Dot 4 made by Brian Dorey: https://www.briandorey.com/post/echo-dot-4th-gen-smart-speaker-teardown. If Amazon was using the same parts he found in his teardown, then I suspect that Echo 4 might be using as amplifiers two TAS5805M, either bridged, either one chip for the woofer and the other chip for the two tweeters, last one being a bit more plausible to me. This amplifier chip is getting a max. of 45 W in mono mode if powered from 21 V, while in our case Echo 4 from my teardown is powered from 18 V instead, so I'm guessing it may rich to a theoretical figure of about 35 W or so.

If you look to Brian's teardown, you'll see that he even unsoldered one metallic shield and unveils the 4Gb Micron Flash Memory NAND chip that stores data, like a SSD does in a regular PC.

 

[trl]

Love a good teardown. If you look on the inside of the woofer with a flashlight you should be able to see if the third woofer terminal goes anywhere.

Per your asking, see below.

Apparently, the pin from the middle is just GND, only the pins from sides are connected to the inner coil. Thanks for your suggestion!

 

[trl]

I'd like to add few thoughts about the intelligent microphones from inside Echo 4. Seems that there are six of them, three on left and three on the right side of the upper semi-sphere, covering completely two sides of the room.

We can see on the left & right sides the six microphones linked together via a barely visible black ribbon cable

There's also a second ribbon cable at 90 degrees that interconnects the six mics via MIC ribbon cable with the BTN PCB

The BTN PCB is then connected with the main PCB from a third ribbon cable

Close-up with one of the six Echo 4's microphones, all having an identical P/N

Two of such Texas Instruments ADC5140 are on the small BTN PCB, taking care of the six microphones
These are 120dB SNR ADC chips, helping the inner processor in separating background noises from the indoor voices
​

 

[Mal]

I had pretty low expectations from this Echo 4, but after few days of listening, given its low price (69 EUR @ Black Friday) and the fact that it was not designed as a small Hi-Fi speaker, but more as an Alexa compatible device, I now think it's quite usable in a bedroom or even in a living room. I personally use it in a 25m2 living room with Tidal playing at 40-50% of volume (that means levels 4 to 5) and get a pleasant audition that fills the room well.

UK Which? magazine had a team of "audio experts" review dozens of Bluetooth speakers. They gave the Echo (4th gen) a Best Buy award and pronounced it the best Amazon speaker they had ever heard - and that comparison included the much more expensive Echo Studio! (That said, Google, Sonos, and several others received the coveted "best buy" award, so Amazon are far from owning this category...)

I did buy one on "Prime day" and am happily using it in my kitchen, I quite often transition from it to my KEF LSXs, in moving from kitchen to living room, and athough the LSXs are (thankfully!) better, the quality transition isn't jarring. Having read the Which? report, I expected the Echo 4 to be quite good, but it's even better than I expected.

 

[Biblob]

Always love a good tear-down!
Is it possible you shorten the y-axis of the acoustic measurements to 50dB scaling? Since that's the standard

 

[trl]

UK Which? magazine had a team of "audio experts" review dozens of Bluetooth speakers. They gave the Echo (4th gen) a Best Buy award and pronounced it the best Amazon speaker they had ever heard - and that comparison included the much more expensive Echo Studio! (That said, Google, Sonos, and several others received the coveted "best buy" award, so Amazon are far from owning this category...)

I did buy one on "Prime day" and am happily using it in my kitchen, I quite often transition from it to my KEF LSXs, in moving from kitchen to living room, and athough the LSXs are (thankfully!) better, the quality transition isn't jarring. Having read the Which? report, I expected the Echo 4 to be quite good, but it's even better than I expected.

Mal, please help me out in identifying something with the below "test":
- make a call between the Alexa app on your phone and Echo 4 ("Alexa, call Echo 4" etc.) and don't keep your cellphone on speaker due to microphonic;
- whisper on the left, then on the right side of the Echo 4 semi-sphere, a bit of blowing wind from your speech would help, then see if the sound on your phone is the same when whispering on left vs. right sides;
- let me know if both sides of mics are delivering the same crisp sound in your cellphone or not.

My Echo 4 seems to be using only the right side of the mics for calls and I'd like to figure out if this is per-design or my Echo 4 is having troubles.

Thank you in advance!

 

[trl]

Always love a good tear-down!
Is it possible you shorten the y-axis of the acoustic measurements to 50dB scaling? Since that's the standard

Hi and thanks! Where exactly, please? Both horizontal and vertical scales are OK, but some graphs are kinda zoomed-out, if that's what you're referring to.

 

[trl]

Also, worth noting that few folks have had troubles with their Echo 4 speakers, issues being resolved either by swapping the defective device by Amazon, either by resetting the device to defaults and deregister/reregister the device again.

 

[trl]

As a follow-up related to Echo 4's high-quality microphone quad ADC chips from inside, here's a great article about it: https://audioxpress.com/news/new-ti...-captures-voice-at-four-time-larger-distances.

 

[MCH]

so this thing has an 4 channel ADC chip capable of 120db SNR and up to 98db sinad at 3$ a pop and this below is how our current ADC chart looks like? interesting

thanks for the review @trl i always find these teardowns of big brands stuff fascinating, what they are capable to cram inside there...

 

[trl]

Need to add a note regarding Alexa devices Low Power Mode: when Ultrasound Motion Detection sensors are disabled the above Echo 4 consumes (in my case) between 2.7-3Wh, while with these sensors disabled the power consumption decreases to 1.1-1.3Wh. For those that want to be Eco friendly I suggest turning off this setting, as I did for now.

Starting now (after I disabled the ultrasonic sensors), I will need to turn off manually (actually I ask Alexa to do it for me) all living lights, Christmas lights and Fire TV as well, given that till now Echo 4 was doing this for me when nobody was in the room (usually when left home or got to bad).

I assume the "ultrasonic" sensors are the mics from around Echo 4, the ones from the pics from my last posts.

 

[Biblob]

Hi and thanks! Where exactly, please? Both horizontal and vertical scales are OK, but some graphs are kinda zoomed-out, if that's what you're referring to.

I mean the frequency response graphs, you use 100 dB scales, which make the frquency graph look more linear than it is . Nothing important or misleading though, just a visual thing.

 

[trl]

UK Which? magazine had a team of "audio experts" review dozens of Bluetooth speakers. They gave the Echo (4th gen) a Best Buy award and pronounced it the best Amazon speaker they had ever heard - and that comparison included the much more expensive Echo Studio! (That said, Google, Sonos, and several others received the coveted "best buy" award, so Amazon are far from owning this category...)

I did buy one on "Prime day" and am happily using it in my kitchen, I quite often transition from it to my KEF LSXs, in moving from kitchen to living room, and athough the LSXs are (thankfully!) better, the quality transition isn't jarring. Having read the Which? report, I expected the Echo 4 to be quite good, but it's even better than I expected.

@Mal could you please check my latest reply to you?

Thank you!

I mean the frequency response graphs, you use 100 dB scales, which make the frquency graph look more linear than it is . Nothing important or misleading though, just a visual thing.

Yes, you're right, this is due to the fact that frequency scale was between 10Hz to 24kHz (fit to vertical scale was fine), but when I zoomed-out to 20Hz-20kHz everything from the vertical scale looked different. Thanks for understanding!

 

[obzobz]

I'd like to add few thoughts about the intelligent microphones from inside Echo 4. Seems that there are six of them, three on left and three on the right side of the upper semi-sphere, covering completely two sides of the room.

How easy would it be to physically disable the microphones? (Who wants open mics in their house these days..)

 

[trl]

Press the top button and the light will turn red, meaning that the mics are disabled. Still, why buying Echo if mics are disabled?

 

[obzobz]

Press the top button and the light will turn red, meaning that the mics are disabled.

AFAIK that's a software disable, which isn't worth very much in terms of safety. (Buggy or malicious software can just decide to turn the mics back on).

Still, why buying Echo if mics are disabled?

Haven't found any good quality WiFi & Spotify enabled speaker in that price range. The Sonos ones are ~4x the price of the Echo. Open to suggestions though!

 

[Doublej]

AFAIK that's a software disable, which isn't worth very much in terms of safety. (Buggy or malicious software can just decide to turn the mics back on).



Haven't found any good quality WiFi & Spotify enabled speaker in that price range. The Sonos ones are ~4x the price of the Echo. Open to suggestions though!

Edifier MS50a perhaps?

https://usa-oss.edifier.com/Uploads/images/2022/02/17/2022021714465316450804138822.pdf