Please note that in the video I refer to these machines as ‘Marpac Dohm’ and ‘Marpac Rohm’. The company Marpac has now merged with YogaSleep though, and they are currently just called the ‘Rohm’ and the ‘Dohm Uno;
Both devices provide simple ways to listen to white noise, without too many options to choose from. They work in very different ways, so it helps to understand the key differences.
The Dohm Uno has an internal fan that forces air through small holes to produce the sound. It’s a gentle sound that’s probably better for relaxation than masking external noise.
The Rohm has 3 digital sounds rather than a mechanical fan: bright white noise, deep white noise, and ocean surf. It’s small and has an internal rechargeable battery, so it’s convenient for travel.
Historically, Marpac has been one of the principal manufacturers of white noise machines, stretching back to the 1960s. In fact, some of the current devices now sold under the YogaSleep name since the company merger are still based on the popular original model.
I decided to combine 2 of their models for this review. This is so you can see the main differences between one of their larger machines that uses an actual fan and a compact machine that doesn’t have a fan, but is better for travel.
The Uno is a simplified version of the original Dohm, which was itself already remarkably simple!
It’s a little smaller than previous Dohm versions, which is good as the original was quite bulky for the bedside table. Despite being smaller, it still has enough weight and grippy feet to stop it from sliding across the table when you use it.
There’s just one button – the on/off button. There’s no volume control, no timers, no additional sounds. The Uno doesn’t even have the dual speed option that the original Dohm did – hence the name ‘Uno’.
When you turn it on, a mechanical fan starts up, and the resulting air is pushed through gaps in the casing of the device. The only option you have is to turn the casing, which adjusts the sound the air makes as it exits the Uno. You can listen to it in action in my video above (starting at 0:30).
I like the sound the Uno produces. It’s natural, gentle and relaxing – much more so than the wind or fan recordings that most white noise machines provide. And it’s interesting that you can finetune the sound of the air, albeit not by that much.
Sound masking and volume
Although I enjoy the soothing sound, it’s perhaps a little too gentle to mask loud external noise. So I think the Uno is one for relaxation rather than a tool to combat your neighbor’s music or traffic outside.
The Uno is hardwired with a long cable and standard wall plug. There is no wireless option, which along with the size, makes it far less practical for travel than the Rohm.
My main issue with the Uno is the lack of features. I understand that it’s intended to be a no-frills, simple device. And that’s exactly what might appeal to some people. But I think an auto-off timer would be a great addition.
Being wired, it’s obviously limited in terms of placement. And despite being smaller, it’s still larger than many other sound machines.
The Rohm couldn’t be more different than the Uno. The most obvious difference is that it’s much more compact: it’s small, lightweight and hardly takes any space in a bag when traveling.
The reason it’s so much smaller is that it doesn’t have an internal fan. This is a key difference to understand when comparing these sound machines.
There are four buttons: on/off, volume up and down, and sound choice. It also comes with a small lanyard so you can hang it up rather than place it on a table.
The Rohm has three different sounds to choose from:
- Bright white noise
- Deep white noise
- Ocean surf
I couldn’t actually find much information regarding the way the sounds are produced. I’ve seen descriptions like ‘digitally generated’, but the company doesn’t provide a clear explanation on their website. I refer to them as recordings in the video, though I’m still not totally sure if they are recordings or are created internally so the surf sounds avoid any noticeable looping.
The important point though is that all three sounds are good quality. Personally, I like the deep white noise best as it’s more relaxing to my ear.
Sound masking and volume
The little Rohm really surprised me with its volume. For such a tiny device, the speaker can certainly roar on the maximum volume. So this might be useful if you’re traveling and find to your horror that your hotel room is right above a busy street.
I found it can reliably mask pretty much all noise from outside the house, whether placed near your bed or by the offending non-soundproof window.
The Rohm comes with a micro USB to USB cable, so you can play it from a USB hub or a computer. Conveniently, it has an internal rechargeable battery, so you can place it wherever you like in a room without needing to be plugged in.
The length of charge will depend on the volume you play it at, but I’ve easily gotten a whole night out of one charge.
Marpac were long known for their internal fan design, so I think it’s a shame that they don’t include a gentle fan sound with the Rohm. And just 3 sound choices is very limited compared to even the most basic of sound machines, which tend to start at around 6.
The buttons need some getting used to. The power button needs to be held for a couple of seconds. And if you noticed in my video, I sometimes had to turn the Rohm sideways to change the sound option, which was strange.
Conclusion – which one is best for you?
Personally, I like both of these sound machines. It’s hard to say if one is better than the other because they serve such different purposes, and both do a good job.
So here’s who I think might prefer each one most:
- If you find gentle fan sounds relaxing, but don’t want to use a large fan in your room.
- If you don’t plan on transporting it anywhere.
- If you don’t need other white noise or nature sounds.
- If you value simplicity over having lots of options.
- If you want a small, lightweight white noise machine to take on your travels.
- If you need louder volume levels.
- If 3 sounds are enough for you and you don’t need endless variety.
- If you prefer a wireless device with an internal battery so you don’t need to keep it plugged in all night.