Sonnet Echo 21 SuperDock Review: The Best Balanced Thunderbolt 5 Dock

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A docking station lets me run one Thunderbolt cable to my Mac and get back a desk full of ports, my displays, and power for the laptop all at once. Sonnet sent me the Echo 21 SuperDock to review, and after living with it on my M4 Max Mac Studio, I think it is one of the best all around Thunderbolt 5 docks you can buy today.

It does a couple of things I have not seen on any other dock, and it also makes a few compromises you need to know about before you spend $500. Here is what it gets right, where it falls short, and how it compares to the Echo 13, the Satechi CubeDock, and the CalDigit TS5 Plus.

What it works with

The Echo 21 is a Thunderbolt 5 dock, but it is not Mac only. Sonnet lists it as compatible with any Apple M-series computer, Intel Macs with Thunderbolt 3, and most Thunderbolt 5 and Thunderbolt 4 Windows machines. It even works with the M-series iPad Pros. Check Sonnet’s site for the full compatibility list before you buy.

I tested it mostly on my M4 Max Mac Studio with two Apple Studio Displays connected. That is a demanding setup and a good way to see how the dock handles bandwidth when it is fully loaded.

The RCA line out is the feature no other dock has

The standout feature, and the one I have not seen on any other dock, is the pair of RCA line outs on the back. You get left and right line out, so you can run the dock straight into powered studio monitors or a mixer without a separate audio interface.

Two things make this better than the usual line out you find on a dock. First, it supports true lossless audio and it genuinely sounds great. I have been running it into my Allen and Heath CQ-12T with my ADAM Audio A7V monitors and it sounds awesome. Second, and this is the part I love, you can control the output volume right from your Mac’s keyboard volume keys. I do not have to reach over to the mixer or around the back of the monitors to change the level.

Every port on the back

The back of the dock is where most of the connectivity lives:

• The host port that runs to your computer, plus a slot for a locking connector so the cable cannot pull out by accident
• Two additional Thunderbolt ports for more displays or external SSDs
• HDMI and DisplayPort, though you can only use one of them at a time, not both
• Four USB 3.1 ports, a mix of USB-A and USB-C
• The RCA line out, plus a microphone input
• A 10 Gigabit Ethernet port, which is still rare on docks

The front ports and card readers

On the front you get a headset jack and five USB ports. Four of them are standard, and the fifth is a more powerful 15W USB-C port, which is the one to use if you want to keep an iPad or a phone charging off the dock. There is also a UHS-II SD card slot and a microSD card slot for pulling footage off camera cards.

The built-in SSD slot and the speeds I got

The reason this is the SuperDock and not the cheaper Secure Dock is the NVMe SSD slot on the bottom. It does not come with a drive, so you add your own, and Sonnet rates it for drives up to 8TB.

Sonnet rates the slot at up to 3,300 MB/s. In my testing, with both Studio Displays plugged in, I was hitting 2700 to 2900 MB/s. That is not the full speed Thunderbolt 5 is capable of, but Sonnet does not overpromise here. They deliberately limited the SSD bandwidth so the 10 Gigabit USB ports and the 10 Gigabit Ethernet all have room to breathe. Even at that reduced speed it is plenty fast for editing video off the drive or running Time Machine backups. I also ran all my Google Drive files off it and it worked great.

Installing a drive is easy. You take out the two screws on the cover, remove one more Phillips screw inside, insert the NVMe at an angle, press it down, and screw it into place. The cover has a built-in thermal pad that pulls heat off the drive and into the enclosure. My advice: just buy whatever good NVMe drive you can find on a deal.

My biggest complaint: too many ports on the front

My biggest complaint after using it for a while is that Sonnet put too many USB ports on the front. Five is more than I need up there. I would rather they had left a single USB-A and maybe two USB-C ports on the front, then moved the extra USB-A and USB-C around to the back. That would keep the desk setup a little cleaner.

Build quality and the two versions

The build is excellent. It is all metal, and there is a Kensington lock slot on the side if you need to physically secure it.

Sonnet makes two versions of this dock. The Echo 21 SuperDock has the SSD slot. The Echo 20 Secure Dock is the same dock without the SSD slot, and it saves you about $50. If you know you will never add a drive, the Secure Dock is the one to get.

What is in the box and 140W charging

In the box you get a Thunderbolt 5 cable and the power brick. The dock delivers up to 140W to a connected laptop, which is enough to fast charge something like a 16-inch MacBook Pro while it is docked, so laptop users are covered too and this is not only a Mac Studio accessory.

10GbE and the Thunderbolt tradeoff

The 10 Gigabit Ethernet port on the back is genuinely handy and, again, rare on docks. But it comes with a tradeoff. Because this dock spends bandwidth on 10 Gigabit Ethernet and the video outputs, you only get two additional Thunderbolt ports on the back instead of three.

This is normal. When a dock adds an SSD or a 10 Gigabit port, that eats into the total bandwidth, and almost every manufacturer ends up cutting one of the rear Thunderbolt ports. It is a small annoyance if you want two Studio Displays plugged in directly. If you have the newer Thunderbolt 5 Studio Displays, you can daisy chain them off a single port and free the other one up.

Running multiple displays

The dock supports up to four external displays, but how many you actually get depends on your computer and its chip. It gets a little tricky because you cannot use the HDMI and DisplayPort at the same time. You can use both Thunderbolt ports for video plus one of the HDMI or DisplayPort outputs, so getting to a full four displays over a single cable may mean daisy chaining over Thunderbolt or getting creative with adapters and splitters.

Running that many displays also eats a lot of bandwidth and can slow the SSD down further, so check Sonnet’s compatibility chart to confirm it will drive the displays you want at the resolutions you want.

The power supply is my other concern

Here is my other concern. The dock ships with a 240W power brick (20V at 12A). That is less than the CalDigit TS5 Plus, which comes with a 330W supply, and CalDigit makes a point of how much power it reserves for USB devices. Sonnet does provide up to 140W to your laptop, which I appreciate, but I worry the 240W brick could get a little tight with everything you might plug in.

The port power backs that up. All the USB ports only supply 7.5W each. The Thunderbolt ports each do up to 15W, and the front super-speed USB-C port does 15W for a phone or an iPad. If you run a lot of bus-powered USB gear, that is worth thinking about.

Pricing

The Echo 21 SuperDock is $500. The Echo 20 Secure Dock is $450, and the SSD slot is the only difference between them. I think the extra $50 for the slot is absolutely worth it, since that drive is so useful for Time Machine, editing projects, or anything else you would use an external SSD for.

The Thunderbolt 5 docks compared

I have been able to test just about every Thunderbolt 5 dock on the market, so here is how the Echo 21 stacks up against the ones people ask me about most.

Dock	Rear Thunderbolt ports	10GbE	Built-in SSD slot	Power brick	Price
Sonnet Echo 21 SuperDock	2	Yes	Yes (add your own)	240W (up to 140W to laptop)	$500
Sonnet Echo 20 Secure Dock	2	Yes	No	220W	$450
Sonnet Echo 13	Fewer (host and a TB port on front)	No (2.5GbE)	Optional, preinstalled	Not stated	About $300
Satechi CubeDock	3	No	Yes	Not stated	About $400
CalDigit TS5 Plus	2	Yes	No	330W	$500

Versus the Sonnet Echo 13

The Echo 13 is Sonnet’s cheaper option. It is made of plastic, has fewer ports, and only has 2.5 Gigabit Ethernet instead of 10 Gigabit. It also puts its host port on the front and uses one of its Thunderbolt ports on the front, which some people like and some do not. It does reserve extra power for that front Thunderbolt port. You can buy it with an SSD preinstalled or bare.

The SuperDock is about $200 more. If you want the 10 Gigabit Ethernet, the RCA line outs, and more USB ports, that is money well spent. If you do not need the video outs or those extras, the Echo 13 can save you real money.

Versus the Satechi CubeDock

Satechi’s CubeDock is another good one. It actually has fewer ports on the front, which I think looks cleaner, and it still has an SSD slot on the bottom. It technically runs a bit faster than the SuperDock too. Where it falls short is the back. It does keep three Thunderbolt ports, which is nice, but there is no 10 Gigabit Ethernet and no video out, so every display has to go over Thunderbolt. It also has only two USB ports on the back versus four here, and two on the front versus five.

The CubeDock is about $400. For $100 more, the SuperDock gives you the 10 Gigabit port and a lot more connectivity, so I think it is a worthy upgrade.

Versus the CalDigit TS5 Plus

The CalDigit TS5 Plus is the one the SuperDock gets compared to most. It has 10 Gigabit Ethernet, a comparable number of USB ports, and the same two rear Thunderbolt ports. It uses a headphone jack for line out rather than true RCA outs like the SuperDock, and it ships with that larger 330W power supply. It has three USB ports on the front, which I actually think is the ideal placement, and you can stand it up vertically or lay it flat.

The TS5 Plus does not have an SSD slot, and it costs the same $500. So on features, the Echo 21 SuperDock gives you more for the money. The one place the TS5 Plus wins is dual USB controllers, which the SuperDock does not have. Those reserve more bandwidth for USB devices. If you mostly run audio interfaces or basic USB gear, you will not notice. Most of my USB-A ports run slower things like a Stream Deck, so I never hit any bandwidth issues on the Echo 21.

Who should buy it and who should skip it

Buy the Echo 21 SuperDock if you want to run lots of devices off a single cable, you want built-in storage, and you want the RCA jacks to plug straight into a mixer or powered speakers without an audio interface. The HDMI and DisplayPort mean you do not need an extra adapter for a non-Studio Display, and you also get the two extra Thunderbolt ports, the 10 Gigabit Ethernet, and plenty of USB.

Skip it if you run a lot of bus-powered devices that need more USB power, if you need to charge several iPads and phones at once, or if you do not care about the storage. Also skip it if two rear Thunderbolt ports is not enough for you, because there are docks that give you three.

The verdict

The Echo 21 SuperDock is an awesome dock from Sonnet. It is pricey, and you have to budget for the NVMe on top, but it is one of the best balanced Thunderbolt 5 docks I have used and a strong challenger to the TS5 Plus thanks to the built-in storage, the RCA jacks, and the rest of the feature set. My biggest wish is that Sonnet had put more power into it the way CalDigit did. If a lot of your devices use their own power anyway, that will not matter much, and this becomes an easy recommendation.