Can voice memos recorded on iPhone be improved clearly?
Table of contents
Factors that make you feel the difference in sound quality from the recorded material
Data that is almost inaudible to conversation is difficult to improve even for professionals
In principle, use earphones for sounds that are difficult to hear.
アプリに実装されたノイズ除去機能をまず試そう（iOS15.3.1/2022)
iPhoneに標準搭載されているボイスメモアプリに簡易的なノイズカット機能が追加されました。「サー」「シュー」という、会話などを録音した時に入ってしまうノイズをボタン一つで軽減してくれます。これ以上のノイズ除去は音声編集用の高度なソフトを覚えるか専門プロに診断してもらったほうが賢明です。
アプリを立上げ
対象ファイルをクリック
操作タブが出てきます
左のボタンをクリック
オプションタブが開きます
ONにする
「録音補正」をオンにします。これで対象ファイルを再生するとノイズが取れて少しクリアになります。（イヤフォンやヘッドフォンが分かりやすい）
Factors that make you feel the difference in sound quality from the recorded material
I'm Yamakawa, who runs a noise removal and repair service for voice data. The voice memo app installed on the iPhone is convenient because you can easily record conversations. However, when I play back the recorded data, there are many cases where I ca n't hear the essential content because there are a lot of extra sounds from the cafes around me that I didn't care about on the spot .
□ Noise that is worrisome when recording
・ Conversation in the next seat
・ The sound of tableware and ice around the drink bar
・ Noise outside the window (car traffic noise, etc.)
・ Greetings from BGM staff in the store
Because the human brain is excellent, it is controlled to focus on conversations and unknowingly distract other noises when the surroundings are noisy . This is the factor that makes you feel the difference in sound quality between the sound you are listening to in the field and the recorded data.
Voice memo handling cases and professional professional improvement difficulty
Couple conversation at a tavern (AA)
Interview at family restaurant (A)
Conversation between husband and wife in the living room (B)
Interviews / interviews in conference rooms where air conditioning is a concern (C)
Multi-person meeting (AA) in a large meeting room
Trouble conversation between contractors at the construction site (B)
Conversation over the telephone handset (AAAA)
Telephone conversation in the car while driving (AAAA)
Conversation away from the microphone (AAAAA)
Lecture with a lot of reverberation (A)
Improvement difficulty A (difficult) ⇄ C (relatively easy)
Comparison of listening to high-performance linear PCM recorders
The above is the improvement difficulty level judged by a professional professional.
It is difficult to improve the data recorded by an amateur with a smartphone or an inexpensive IC recorder .
Even if an amateur who does not touch the voice editing application on a daily basis uses the free application in the dark clouds, there is a high probability that it will end up in vain .
Before and after examples of selfie videos
Data that is almost inaudible to conversation is difficult to improve even for professionals
Some smartphone apps and free voice editing software have a simple noise canceling function .
If used properly, it can be used to suppress the rustling of the surroundings, but it should be considered almost impossible to repair when the conversation volume is clearly low .
Specialized know-how is required for voice restoration. Even with professional video editors, it is not uncommon to outsource only sound conditioning to a vendor.
As a professional professional, we are working on removing noise from over 100 voice memos a year, but the improvement adoption rate of voice memos is about 60% . The reality is that there are many give-ups.
It is a rule of thumb to audition with earphones and headphones for sounds that are difficult to hear.
If possible, earphones for music of 8,000 yen or more are better
Voice memo Reproduction of hard-to-hear conversations recorded It is a rule of thumb to use headphones and earphones with high resolution . .. Many of the speakers that can be installed as standard equipment on smartphones and personal computers are of the lowest class, "just listen for the time being", so they are not suitable for listening to recorded conversations.
Even if you ask a professional to remove noise, it is difficult to experience the improvement effect if the speaker or earphone that reproduces the data has a low reproduction ability. Before asking a professional, first spend money on quality music earphones and headphones.