A comparison of specs, key information, reviews, and best pricing from top retailers
Last updated -- hours ago | Report incorrect information
Company ProductName Specs
Company ProductName Specs
What we think
The PerfectRec Earbuds or Headphones team Learn more
Updated January 10, 2024·
The Sennheiser HD 350BT over-ear, closed-back headphones are less expensive and offer good sound quality with features like AptX Low Latency, which can be great for TV and gaming due to reduced lag. They also have long battery life and integrated controls. On the other hand, the Thieaudio Monarch Mk II earbuds are significantly more expensive, but they deliver exceptional sound quality with a hybrid driver setup including BA, dynamic, and electrostatic drivers. Therefore, if budget is a concern and you need a convenient, low-latency wireless experience for a variety of uses, go for the Sennheiser HD 350BT. However, if sound quality is your top priority and you're willing to invest more, the Thieaudio Monarch Mk II could be the superior choice, especially for dedicated music listening with high-fidelity recordings. Give Feedback
this description is based on the product variant with some specs and product variant with some specs. At the time of writing, the variant with some specs cost some dollars and the variant with some specs cost some dollars.
Advantages of the Sennheiser HD 350BT
- Good for phone calls
- Excellent for gaming
- Excellent for TV and video
- Very good for air travel
- Very good for podcasts and audiobooks
Advantages of the Thieaudio Monarch Mk II
- Best in class for music
Key differences
Music
7.0
9.5
The Thieaudio Monarch Mk II is best in class for music, while the Sennheiser HD 350BT is good.
Gaming
9.1
6.7
The Sennheiser HD 350BT is excellent for gaming, while the Thieaudio Monarch Mk II is only fair.
Phone Calls
7.4
5.1
The Sennheiser HD 350BT is good for phone calls, while the Thieaudio Monarch Mk II is poor.
Battery
33.0 Hours
N/A
The Sennheiser HD 350BT has 33 hours of battery life. The Thieaudio Monarch Mk II does not have a battery.
Cost
$80
$999
$50
$100
$150
$200
$250
$300
$350
$400
The Sennheiser HD 350BT has a price of $80 and the Thieaudio Monarch Mk II costs $999.
Build Quality
8.2
9.0
The Thieaudio Monarch Mk II has excellent build quality, while the Sennheiser HD 350BT has very good build quality.
Let Us Help Find Your Perfect Headphones
Find your new headphones
Key similarities
Podcasts and Audiobooks
8.3
7.9
Although they have very similar scores, PerfectRec considers Sennheiser HD 350BT to be very good for podcasts and audiobooks, while the Thieaudio Monarch Mk II is good.
TV and Video
9.0
8.8
Although they have very similar scores, PerfectRec considers Sennheiser HD 350BT to be excellent for TV and video, while the Thieaudio Monarch Mk II is very good.
Noise Reduction
6.0
6.0
The Sennheiser HD 350BT and Thieaudio Monarch Mk II are both only fair for noise reduction.
Give feedback
We’re constantly working to improve.
How the Sennheiser HD 350BT and the Thieaudio Monarch Mk II compare to other earbuds and headphones
Spec Comparison
 |  | |
| Sennheiser HD 350BT | Thieaudio Monarch Mk II |
GENERAL | |||
|---|---|---|---|
| Price | |||
$80 | $999 | ||
Brand | |||
Brand | Sennheiser | Thieaudio | |
Release Date | |||
Release Date | January 1, 2020 | October 1, 2020 | |
Form Factor | |||
Form Factor | Headphones | Earbuds | |
Connectivity | |||
Connectivity | Wireless | Wired | |
SOUND | |||
|---|---|---|---|
Music Score | |||
Music Score | 7/10 | 9.5/10 | |
Phone Calls Score | |||
Phone Calls Score | 7.4/10 | 5.1/10 | |
Gaming Score | |||
Gaming Score | 9.1/10 | 6.8/10 | |
TV and Video Score | |||
TV and Video Score | 9.1/10 | 8.9/10 | |
Exercise Score | |||
Exercise Score | 6.3/10 | 4.5/10 | |
PERFORMANCE | |||
|---|---|---|---|
Battery life | |||
Battery life | 33 Hours | N/A | |
Wireless charging | |||
Wireless charging | No | N/A | |
Charging time | |||
Charging time | 2 Hours | N/A | |
Bluetooth version | |||
Bluetooth version | 5 | N/A | |
FEATURES | |||
|---|---|---|---|
Active Noise Cancelling | |||
Active Noise Cancelling | No | No | |
Noise Reduction Score | |||
Noise Reduction Score | 6/10 | 6/10 | |
Virtual Surround | |||
Virtual Surround | No | N/A | |
Android App | |||
Android App | Yes | N/A | |
iOS App | |||
iOS App | Yes | N/A | |
Mic Quality | |||
Mic Quality | 8.5/10 | N/A | |
BUILD AND DESIGN | |||
|---|---|---|---|
Build Quality | |||
Build Quality | 8.2/10 | 9/10 | |
Comfort score | |||
Comfort score | 7.6/10 | 7.6/10 | |
Size | |||
Size | N/A | Large | |
Weight (headset or single earbud) | |||
Weight (headset or single earbud) | 238 Grams | 9 Grams | |
Microphone style | |||
Microphone style | Integrated | N/A | |
Shopping
Sennheiser HD 350BT
See more
Dig into reviews and images
Soundguys
Lily Katz | September 2023
"Sennheiser nails just nearly everything about the Sennheiser HD 350BT headphones. Sound quality is excellent, and the high-quality Bluetooth codec support is a rarity at this price point. If you don’t care for high-tech features like automatic ear detection, you’ll be delighted with these portable headphones."
Thieaudio Monarch Mk II
See more
Dig into reviews and images
Audiophile On
Audiophile On | August 2021
"No other earphone I have listened to in the past 12 months has given me as much joy as the Thieaduio Monarch MKII. One of those IEMs will make you question where we can go from here. The sound is jaw-dropping, leaving you wanting more and more. It makes you want to run through your entire music library and reevaluate. It makes you not feel bad about paying full price for them, especially in a hobby where buyers' remorse is genuine. For me, it's top tier, rivaled by a few but not surpassed."
Get a great deal on the Sennheiser HD 350BT or the Thieaudio Monarch Mk II
About Sennheiser
A family-owned company, Sennheiser is a German, high fidelity, audio equipment manufacturer founded in 1945. Their consumer audio division is now owned by the Swiss hearing aid and cochlear implant manufacturer Sonova. Sennheiser offers a wide variety of, very high quality, audio equipment solutions, from headphones to earbuds, full sets of monitoring speakers, amplifiers and microphones. They also make what is widely regarded as the best, and most expensive, headphones in existence, the HE-1 Orpheus, costing a whopping $59,000 dollars.
About Thieaudio
Thieaudio is the in-house brand of Linsoul Audio, a Chinese earbud and headphone retailer specializing in what the community lovingly calls Chi-fi, that is high fidelity brands out of China. Thieaudio was established in 2019 as the creative engineering branch of Linsoul. As of today, they market three different lines of earbuds, Voyager, Legacy and the extremely well-received Monarch.
Give feedback
We're constantly perfecting our model
Earbuds or Headphones guides you might be interested in
More comparisons for you
Compare Sennheiser HD 350BT vs. Shokz OpenMove
VS
Compare Sennheiser HD 350BT vs. Beats Studiobuds
VS
Compare Sennheiser HD 350BT vs. Soundcore Life Q30
VS
Compare Thieaudio Monarch Mk II vs. Bang and Olufsen Beoplay H95
VS
Compare Thieaudio Monarch Mk II vs. Audeze LCD 2 Classic
VS
Compare Thieaudio Monarch Mk II vs. Focal Elex
VS
FAQs
FAQs about earbuds and headphones
Why trust us
This information was produced and vetted by the PerfectRec earbuds & headphones team. We are a product research and recommendation organization that meticulously reviews and evaluates the latest earbuds or headphones information and makes it digestible for you.
By the numbers
108
Earbuds and headphones evaluated
11,340
Earbuds and headphones stats compiled
15
Proprietary Earbuds and headphones ratings developed
122,900
Recommendations made
18,435
Consumer hours saved
About the Earbuds or Headphones team
Joe Golden, Ph.D
CEO and Earbuds and Headphones Editor
Joe is an entrepreneur and lifelong electronics enthusiast with a Ph.D in Economics from the University of Michigan.
Jason Lew
Staff Expert & Software Engineer
Jason is a staff expert and software engineer that has been making laptop recommendations for 7 years and moderates one of the largest laptop subreddits.
Chandradeep Chowdhury
Staff Expert & Software Engineer
Chandradeep is a staff expert and software engineer and expert in televisions and monitors. He’s been making monitor recommendations for ten years.
Luis Torres
Earbuds and Headphones Expert
Luis is a Mexico-based headphones expert. He’s been making headphone recommendations for five years and has close to 100 pairs in his personal collection.
Featured in
