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You can zoom into any corner of this 8K photo online and still see the details of the picture. Let's put this concept to the audio to explain high resolution audio. High resolution audio content include extra high frequency information. As shown below. The differences won't be noticed until you play the audio in the large theaters or the high quality amplifier sound systems. In those cases the audio gets largely amplified or you can say zoomed in.
The most popular high resolution audio format is DSD audio. DSD stand for Direct Stream Digital audio. It is a new hot topic on the audio enthusiastic nowadays.
What is DSD different to normal digital audio?
The best example to explain this technology is to use analogue recording tape. The idea of DSD is to digitally recording sound use analogue approach. The analogue audio recording is the linear recording technology. This approach has been used since the beginning of the audio recording. The method is simply sample the sound directly in the linear order. For example the vinyl recording. The machine writing the sound directly on the vinyl disk continuously until the music stopped. This is the same approach DSD used. Because it is the digital process without need for actual moving mechanical parts. The DSD recording result is fascinating on the sound quality without noise.
So why we are not all use DSD instead?
There are two challenges to make DSD the standard. One is the file size. The DSD audio file is almost 100 times bigger compare to a lossy mp3 audio file for the same song. Photo below shows the contrast of a 3.4 MB 92 kbps mp3 audio file can take up to 403MB if it is in DSD 5.6MHz format. That means your iPhone can only hold 80 DSD songs with the 32GB of free space.
Another challenge is the playback decoding software. DSD technology was developed after PCM technology. Not like 8K photos the DSD used completely different data storage format. Normal audio players designed for PCM are not able to play the DSD audio format this included all windows and mac based music players. DSD audio requires special soft and hardware to playback .Or use an extra DAC converter to output PCM or MP3. Either way are not convenient for us.
So why is mp3 audio most accessible?
Mp3 audio shared the same PCM Pulse-code modulation data storage method. You can think it is a compressed cut down version of the PCM audio. The PCM technology is widely used and available on all existing audio devices. To put two technology to the comparison you can see from the photo below. It shows you the different ways of sampling sound.
So is DSD worth it ?
We mentioned in previous blogs. Perception sound and audio format really makes different when you had right playback devices. Same principles applied here. If you had a superior quality sound system and headphone. Indeed higher the quality source will give you more details and perceived immersion. This can be proved by both listeners and sound measurements. However, if you are playing DSD audio from your laptop or mobile phone speakers. The perceived sound quality is varius by listeners and the sound quality measurement will be the same to the playback device's best measured sound quality.
DSD format on OPSIS II ?
OPSIS II had two inputs. One is wireless bluetooth that used lossless compression to give you best audio playback quality. When you stream DSD converted audio use bluetooth to OPSIS II. The playback quality will be the best of your streaming service or device can support. If you are input use analogue line input. OPSIS II's DAC will give you best digital to analogue conversion possible for the human perception.
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您可以放大這張8K照片的任何角落，但仍然可以看到圖片的細節。讓我們將此概念應用於音頻來解釋高分辨率音頻的區別。如下所示高分辨率音頻內容包括超高頻信息。除非您在大型劇院或昂貴的放大器音響系統中播放音頻，否則這差異不會被注意到。在這種情況下，音頻內容會被大大放大，或者您可以說拉近了。
DSD音頻是最受歡迎的高分辨率音頻。 DSD代表Direct Stream Digital是當今熱衷音頻的新熱點。
與普通的數字音頻有什麼不同？
解釋該技術的最佳示例是使用模擬錄音帶。 DSD的想法是使用模擬線性方法數字記錄聲音。模擬音頻記錄是線性記錄技術。自從歷史上有錄音開始就使用它。該方法是直接以線性順序採樣聲音。例如黑膠唱片。機器會連續不斷地直接將聲音寫入黑膠唱片，直到音樂停止。這與DSD使用的方法相同。因為DSD是數字過程，不需要實際移動的機械零件。因此，DSD錄製的結果令人著迷，而無噪音。
那麼為什麼我們不使用DSD呢？
使DSD成為標準存在著兩個挑戰。一個是文件大小。與同一首歌曲的有損mp3音頻文件相比，DSD音頻文件幾乎大100倍。下圖顯示了3.4 MB 92 kbps mp3音頻文件（如果採用DSD 5.6MHz格式）可能會佔用403MB的對比度。這意味著您的iPhone在32GB的可用空間中只能容納80首DSD歌曲。
另一個挑戰是回放解碼軟件。 DSD技術是在PCM技術之後開發的。 DSD不像8K照片那樣。DSD使用完全不同的數據存儲格式。專為PCM設計的普通音頻播放器無法播放DSD音頻格式，包括所有基於Windows和Mac的音樂播放器。 DSD音頻需要特殊的軟硬件音頻播放器來播放或使用額外的DAC轉換器輸出PCM或MP3。兩種方式對我們都不方便。
那麼，為什麼mp3音頻最通用？
MP3音頻共享相同的PCM脈衝編碼調製數據存儲方法。您可以認為它是PCM音頻的壓縮版本。 PCM技術被廣泛使用，並且可以在所有現有音頻設備上使用。要將兩種技術進行比較，您可以從下面的照片中看到。它向您展示了採樣聲音的不同方法。
那麼DSD值得嗎？
我們在以前的博客中提到過。使用高品質的播放設備時，感知的聲音和音頻格式確實會有所不同。同樣的原則在這裡適用。如果您擁有優質的聲音系統和耳機。確實，更高質量的信號源將為您提供更多細節和可感知的沉浸感。聆聽者和聲音測量都可以證明這一點。但是，如果您正在從筆記本電腦或手機揚聲器播放DSD音頻。聽眾感覺到的聲音品質是沒有不同的，並且對於聲音質量最佳的同一播放設備，聲音質量的測量結果相同。
OPSIS II上的DSD格式？
OPSIS II有兩個輸入。一種是使用無損壓縮的無線藍牙，可為您提供最佳的音頻播放品質。流式DSD轉換後的音頻時，請使用藍牙連接OPSIS II。播放質量將是您的流媒體服務或設備可以支持的最佳音質。另一種是直接類比輸入，則使用模擬線路AUX LINE輸入。 OPSIS II的DAC將為您提供最佳的數位類比轉換提供最佳的音頻播放品質。