top of page
  • Writer's pictureinToit Reviews

Opera Factory OS1 PRO: "Ah... we're dealing with a PRO..."

Hey guys, welcome back to the Neighborhood! Your Friendly Neighborhood Reviewer coming at you with another interesting budget IEM. The Opera Factory OS1 PRO. The Opera Factory OS1 PRO should not be confused with its prior iteration the OS1. And while I have not heard that IEM myself, by all accounts, that earphone (the OS1) was somewhat dark and bloomy. So, how did Opera Factory do with the retune of the PRO version? Let’s get InToit!

The build here is a bit of a mixed bag. These are very light weight, and come with a very nice set of tips, which makes these set very comfortable to wear. But the shell is composed of a light-weight plastic, and it is aesthetically somewhat flashy without being gaudy or going overboard. Yet, the cable is barely better than one from a Blon series IEM, although some additional attention was paid to the in-line mic, Y-split, and initiation and termination connections. The ear hooks are plastic wrapped for comfort, but more aggressively hooked than other sets. Nevertheless, I didn’t really find this to be a problem for me when this set was worn, but it could be a problem for others with larger ears. My primary criticisms of the build here is that it is a bit too light in weight, and I wish the cable material utilized was a little more rugged.

Regarding its sound, this is somewhat of an extreme V-shaped sound signature, but seems to be tuned with inoffensiveness in mind. Instead of being harsh in the treble, or bloomy in the bass, the OS1 Pro is fast, articulate for its price, and very precisely rolled at both its ends. Presenting an overall pleasing picture to its listener, with good tonality, and clarity for its price. For a retune of an inexpensive, basshead IEM, I’m not sure if the OS1 PRO could have been retuned any better?

Since this is a basshead IEM, we’ll start with the bass. Overall, it is a relatively fast, punchy, thumpy, bouncy bass; derived mostly from the mid and upper bass regions, with just enough subbass presence for some warmth and character. In other words, its subbass presence on most music is somewhat less presence; which results in increase definition in the bass region, and less bleed or bloom to come out of it. I think Opera Factory was smart here to choose graphene as its driver material here to deliver this type of fast sound, and separate this IEM from other ones in the market place at, or around, this price. In this case, it may not wow you with its bass detailing or resolve like the KBEAR KS2, as Opera Factory appears to designed things with more of an integrative, pleasing approach in mind.

Upper mids are well articulated, and vocal tonality and clarity was surprising clear, clean, and natural sounding at this price. Lower mid-range instrumentation and male vocals were substantially more in the mix compared to female vocals, but lucidity and articulation remained well done. Even when some components of the mid-range are presented more in the background on occasion, they still come across as transparent and articulate.

The same goes for the treble response. The treble is rolled off at the top-end, but done so in a pleasing way; remaining apparent, and with some sparkle, even when some recession is evident. It is lively and mildly boosted without going overboard- never coming across as harsh, strident, or with over accentuation. This makes this set great for modern music genres like pop, rap, hip-hop, and others; which might be a bit boosted or lively up top for certain sets. At times, the upper regions of the treble are presented further out, at a distance, but this enhances psychoacoustics to present dimensionality well. Furthermore, it contributes to this earphone’s rather relaxed nature, as the end of the harshest notes are pleasantly blunted. So, if you are treble sensitive, but like treble detailing, this may be a good set for you to consider. Unlike something like the KBEAR Lark, which just falls off at 9K, sounds are well extended, even when accentuation is reduced.

Overall tonality is relatively neutral with slight warmth from its low-end emphasis and rolled tones. For an IEM targeted towards bassheads, this was a welcomed surprise- as were its graphene driver’s speedy nature and resolving character. Soundstage is average in width, but dimensionality it somewhat enhanced, and decay is well implemented. Separation and distinctiveness of instruments were good for the price.

I compared the OS1 PRO to other similarly priced IEMS such as the Blon BL-01, Blon BL-03, and the Moondrop S.S.R. Clarity and resolution capabilities were most similar to the S.S.R., and in some ways the OS1 PRO may have even been more articulate. So, with regard to its resolve overeall, I found the OS1 PRO to be superior to the Blons. Low-end prominence was most akin to the BL-01; but much quicker and more tightly controlled in the mid-bass in comparison. While mids were somewhat less emphasized than in the case of any of the others in comparison here, mid-clarity was comparable, and treble detailing was more present and sophisticated in the OS1 PRO. But none of the treble presentations here (including the OS1 PRO) should be described as “in-your-face” by anyone.

But, in summary, the OS1 PRO is somewhat of an extreme V for bassheads, but presented in an inoffensive and pleasing way overall. It is rolled off skillfully at both ends without too much obfuscation or sonic loss at either tail. Further, the clarity and resolution of the OS1 PRO were also surprise at this price point, and it at least keeps up with other recommendations that bassheads gravitate towards in the price-range. While its build isn’t stellar, it has its shining moments, as, In this instance, Opera Factory appears to have focused more on what counts here: the sound. Nevertheless, this is more of a fun sound signature than an accurate one, yet still a presentation whose speed, sparkle, and pleasing character I do enjoy. It’s not going to get my highest recommendation, but I like where Opera Factory is going with this one.

InToit Reviews Twitter:

Join the InToit Reviews Discord Server:

846 views0 comments

Recent Posts

See All


Post: Blog2 Post
bottom of page