This is the English edition of a review from my Japanese YouTube channel, iestaLife. I review gadgets from my home studio in Japan, so product links go to Amazon Japan.
Quick take
COREIR ear tips are a popular way to change how your earphones sound. I bought the brass version two and a half years ago and used it on my Technics wireless earbuds. After leaving them in the charging case for a few months, I found green corrosion (verdigris) on the brass parts. The brass COREIR tips still sound great, crisp and clear, but if you leave sweat on them they can corrode, so regular cleaning is a must.
What I tested
- COREIR BRASS ear tips by Nippon Dics, a Japanese maker. A brass (yellow copper alloy) part sits in the sound path
- Used on Technics wireless earbuds for about two and a half years
- Also mentioned: COREIR AL ALLOY, the aluminium alloy version
What I found
- Just fitting them makes the sound more defined. They lift the sound of earphones you already own.
- For the last few months I mostly used other earphones and left the Technics in their case with the COREIR tips on. When I opened the case again, the brass parts had green corrosion on them.
- Brass can react with moisture and the salt in sweat to form verdigris, a blue-green patina. These tips sit in your ears, so I think leaving them for a long time with sweat and dirt on them is what caused it.
- Verdigris is generally considered not to be a serious health concern. Still, it is not pleasant on something that goes right into your ear canal.
- I cleaned them off with a cotton bud. I do not think the product itself is at fault: I had used them for over two and a half years and then left them for months with no cleaning.
Who it’s for
I still recommend the brass COREIR tips for their sound. If you already use them, check yours and get into the habit of giving them a quick wipe after each use. If you are buying now and want less upkeep, or the idea of corrosion bothers you, the aluminium alloy COREIR AL ALLOY is worth considering instead.
The video is in Japanese.
Limitations
This is one pair, used on one set of earbuds, and the corrosion followed months without cleaning. I have not tested the aluminium alloy version for corrosion. Prices and specs are as of the time of recording.
Products
Nippon Dics COREIR BRASS ear tips (brass): on Amazon Japan
Nippon Dics COREIR AL ALLOY ear tips (aluminium alloy): on Amazon Japan
The Amazon Japan links above are affiliate links. As an Amazon Associate, I earn from qualifying purchases. Check the listing for the exact model, current price and shipping availability in your region.
More reviews in English
All Earbuds, Speakers & Audio (35) →Browse all English reviews →
This review is also available in Japanese.