Whizzer Opera Factory OS1 Pro Earphones Review – A Bass Cannon for Under $30

Whizzer Opera Factory OS1 Pro Fit

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Current testing methodology is v1.2

Release Date
May 30, 2019
Price not available
5.4 z
7.6 x 3.1 x 1.9 in

Another set of IEMs suitable for bass lovers is the Whizzer Opera Factory OS Pro 1

These IEMs are manufactured by the Chi-fi brand Whizzer but it’s being marketed in partnership with yet another Chi-fi brand KB Ear.

For around $24, they can be considered a budget set but if you’ve been reading my reviews, then you’d know that you can get impressive sound for way less.

So how did these IEMs do? Let’s get to it!

Also Consider

Whizzer Opera Factory OS1 Pro

IEMs perfect for bass lovers.

Price Range: $
Brand: Whizzer
Whizzer Opera Factory OS1 Pro Fit IEM


The Opera Factory OS1 Pro is a 10mm dynamic driver IEM from Whizzer, which is a well-known brand in the budget audiophile scene.

With a humongous dynamic driver, you can already guess that boom and bloom is this pair’s business. Sadly, it’s a one-trick pony as it doesn’t handle a variety of genres too well.

The Whizzer Opera Factory OS1 Pro may not be that versatile compared to other sets but what these IEMs do quite well is bass. Really. Fun. Bass

The Specs

  • Driver:  10mm Graphene Dynamic Driver
  • Frequency response:  20Hz-20000kHz
  • Impedance:  22Ω
  • Sensitivity:  112db/mw

What’s in the Box?

  • Whizzer Opera Factory OS1 Pro earphones
  • 3.5 mm cable
  • 6 x stock ear tips

Stuff I like

  • Big boomy sub-bass
  • Punchy heart-beating mid-bass
  • Fast transients
  • Warm sound signature

Stuff I like less

  • Veiled midrange
  • Imaging
  • Resolution
  • Poor cable quality

Comparable products to consider


Another pair of IEMs that cater to bass lovers, the QKZ x HBB is great for bass-heavy tracks while versatile enough to sound good with other genres.

First Impressions

Unboxing the Whizzer Opera Factory OS1 Pro had a premium feel to it.

These IEMs were packaged well in a black box with black, white, and gray graphics all over it, while the model name is printed in gold letters. The packaging and how these IEMs were presented look really good.

Once you open the box, you get a foam tray that contains IEMs while the included accessories are packaged beneath it.

When listening to Opera Factory OS1 Pro for the first time, I waited for that glaring feature that jumps at you when a track rolls, and with this set, it was definitely the bass. These IEMs had bass that filled your whole ear canal and not only that, it’s quite tactile as you can feel it in your chest too. 

With just this, I was immediately satisfied and didn’t pay attention to anything else but its most inherently good feature. They were automatically designated as the “bass IEM”. 

Whizzer Opera Factory OS1 Pro - Design
Transparent glittery shell | Make Life Click

Build Quality

The Whizzer Opera Factory OS1 Pro IEMs are made from a plastic material. They’re lightweight but they don’t feel cheap at all.

The included cable is thin. It looks like it’s prone to tangling but a simple cable upgrade will fix that so I won’t consider it a dealbreaker. 

All in all, these IEMs get points in terms of build quality.

Fit and Comfort

The Whizzer Opera Factory OS1 Pro sits comfortably on my ears. 

Because they’re mostly made from plastic, these IEMs provide the ears with somewhat of a breather from the weight it usually carries with other sets. 

With fit, I couldn’t get a good seal with the included ear tips so I switched them out for some Spinfit 100’s and they did the trick. 

With plastic-bodied IEMs like the Opera Factory OS1 Pro, I expected that they’ll fit snuggly in my ears and they’ve met that. I could wear them for long periods without feeling any discomfort, so they get ten out of ten in this department.

Sound Quality

The Whizzer Opera Factory OS1 Pro has a warm sound signature with a large emphasis on the bass region. 

The midrange and the treble are a flat presentation and sound farther away from the listener. This isn’t to say that the treble is dull, it’s just that in the context of the overall tuning, the treble sounds flatter than it would be on its own. 

For listeners that lean towards a monitor or neutral sound, these IEMs will prove to be overwhelming in the bass department. 

If you’re a bass lover, then you’ll love how this set is tuned.

Whizzer Opera Factory OS1 Pro - Cables
Features detachable cables | Make Life Click


This set means business in this region. The bass is present on every track and will be the main focus. 

From the sub-bass to the mid-bass region, it’s elevated in a sort of round peak that covers a wide area of the graph that slowly eases into the mids. From its graph, we can sort of deduce that there’s a lot of bass quantity but due to the wide area that the bass is boosted on, it will naturally lack finesse. 

The Opera Factory OS1 Pro does have adequate texture but it’s a little fuzzy. The sub-bass will sound like blobs of deep rumble rather than a controlled growl. What you’re getting is certified boom and bloom. 

As for the mid-bass, these IEMs punch really hard and the sound feels like you’re standing in front of a large sub-woofer speaker and feeling it in your chest. 

Like the sub-bass, the mid-bass lacks control. I wouldn’t say by a large margin, but a little taming would work well for it. 


From the bass region, the curve continues to descend until it scoops out at the 1kHz mark gradually rising to a round peak at 2.5kHz. 

This part of the Opera Factory OS1 Pro’s graph explains why the mids sound pretty veiled as if the vocals are coming from underwater. 

Is this a deal breaker? For folks that like their midrange clean and clear, it will disappoint. In a way, it’s a caveat but it’s somehow redeemable. 

To some, this midrange veil can come across like a heavy reverb, and depending on the track that they’re listening to, it could actually work in their favor. 

Whizzer Opera Factory OS1 Pro Fit Retail Box
Well-designed and fun-looking packaging box | Make Life Click


The treble from the graph peaks at the 4 and 10 kHz range. It has some good air and texture, plus good details. 

The snare hits and cymbal hits are crispy but they’re put a step back by the timbre. 

Overall the treble doesn’t seem to be fatiguing, and that’s good or bad depending on how you like your treble. 

Because of how these IEMs are tuned as a whole, I think how the treble is handled is appropriate and it fits in well with the sound signature.

Test Tracks

Since the Whizzer Opera Factory OS1 Pro is a set for bass lovers, I’ve included tracks that have great synergy with its tuning.

  • MAYDAY by The Fat Rat ft. Laura Brehm (Melodic Glitch Hop) – This particular track was on repeat when I listened to it on the Opera Factory OS1 Pro because it seems like it was made for these IEMs. The vocals benefitted from that midrange veil because of how reverb is handled. The bass hits deep and punches up nicely. The treble, on the other hand, was able to reproduce the reverb in the mix very well, conveying that wider stage. This track became addictive on these IEMs, although it wasn’t anything special with other sets.
  • As It Was by Harry Styles (Pop) – The constant cymbal and snare dynamic on this track comes in hard and engages you until the end. This is another track that can ride that wave of the reverb illusion and sound good without making the mids sound like they’re veiled. The staging is good and the details are apparent. This track isn’t the busiest and that’s why the Opera Factory OS1 Pro doesn’t technically struggle with the playback.
  • Alone by Marshmello (EDM) – I have almost no words on this track as EDM is the holy grail for these IEMs. There’s no off-chance that vocals or preference in treble sparkle will ruin the experience for you as there’s only minimal singing and more electric instruments and bass when it comes to EDM. This is a really fun track to listen to, as the bass is big and punchy. The instruments sound clear and are interlaced with the bass hits, making them almost euphoric. 
  • Bangarang by Skrillex ft. Sirah (Dubstep) – There’s absolutely no reason for a track as old as Bangarang to hit so hard on these IEMs and yet it does. The instruments resound clearly and there’s good texture on the lower midrange for when the wobble drops along with the shuffling bass. It’s just so satisfying. A Skrillex playlist on the Opera Factory OS1 Pro is sufficient enough to dose you with enough endorphins to make your day. 
  • Party Rock Anthem by LMAO (House/Electronica) – This is another song with not too much importance placed on vocals. The electronic instruments are rendered with really good texture and are closely cusped with the bass hits. The bass on this track is sometimes deep and doesn’t include mid-bass, but on some parts the reverse is true. You can never guess what comes next when listening and you just sit there enjoying the music. It’s a very dynamic and groovy track.
Whizzer Opera Factory OS1 Pro
Comes with noise isolating design reduces up to 90% outside | Make Life Click


The Whizzer Opera Factory OS1 Pro is a solid IEM offering and a unique one in its price range as it deflects from the oversaturated neutral Harman tuning that dominates the budget Hi-Fi scene.

It’s not a one-size-fits-all IEM and it won’t cater to everyone’s taste, except the bass heads. It’s a set that’s unafraid to do something different unlike other IEMs and this is why I like them.

in Ear Headphones Earbuds, OperaFactory OS1 Over Ear Buds Gaming Earbuds IEM 3.5mm Stereo in Ear Earphone Premium Bass Noise Isolating with Mic Microphone for Running Sports Workout …
Whizzer Opera Factory OS1 Pro

These IEMs are perfect for EDM, dubstep, and certain pop songs. You can also use it for games as the explosions will sound better but it won’t suit games that need sound cues for a competitive edge. 

For gamers, bass lovers, and people who dig a really fun sound, the Whizzer Opera Factory OS1 Pro is easily a recommendation as it’s one of the few bass cannon IEMs under $30.

Whizzer Opera Factory OS1 Pro - Design
Whizzer Opera Factory OS1 Pro
Sound Quality
Build Quality
Comfort and fit
Reader Rating0 Votes

Gavin is a college student who has a lot going on. From collecting IEMs and modding mechanical keyboards, to different hobbies like digital drawing, music mastering and cooking. It is safe to say he is a complete multi-faceted geek (and he's kinda cool too)

This post was last updated on 2024-05-15 / Some images from Amazon Product API & some links may be affiliate links which may earn us a commission from purchases.

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