The 3.5mm end: "BD earphone 8 Unit" is a custom earphone that is easy to drive and has a sound field setting of sound field 4 [high-frequency extension]. It uses the Apple original 3.5mm adapter with a recommended volume of 35%. Before connecting it to your phone, make sure to plug in the earphones first and then connect the "Beam 3 PLUS" to your phone. The "Beam 3 PLUS" has a power-saving automatic detection feature, which has been available in previous generations of products.

Under low gain, the sound coherence is slightly improved compared to the Apple original 3.5mm adapter. This improvement can be perceived in all sound aspects, providing more intricacy and variations in sound lines. It also enhances the richness of the sound base, reducing any slight blurring. The most noticeable change is in the low-frequency range, where the structure becomes more solid and there is increased depth and flexibility. Overall, there is a greater sense of dynamic energy, slightly warmer tones, and a rich and relaxed sound experience. The sound field becomes slightly smaller and more focused towards the center, creating a closer and immersive soundstage.
On the iPhone, the volume control on the "Beam 3 PLUS" is synchronized with the phone. Adjusting the volume button on the "Beam 3 PLUS" will correspondingly increase or decrease the volume on your phone. However, when using Bluetooth output, the "Beam 3 PLUS" and the phone operate independently. The power supply for the "Beam 3 PLUS" is self-contained, eliminating any concerns about draining your phone's battery.


4.4mm : In the balanced end, the control of Linkin Park - Victimized will reach a more perfect state, especially in the chorus section. The instruments are played together with strong low-frequency impact. The overlapping that was previously present at 3.5mm will be greatly reduced, leaving only a trace. However, the overall resolution has been greatly improved, with the layers and nuances of the music itself becoming more apparent. The cymbals are crisp, delicate, and transparent, making it much more enjoyable to listen to. In addition, the low frequencies become deeper and more intense, creating a sense of heaviness. However, the sound does not spread throughout the entire soundstage after being hit, so on the drums, although the sound around the drums is somewhat blurry, it remains concentrated in its original position. This means that it does not interfere with the performance of other sounds, resulting in a warm, rich, and energetic overall sound. Although this is somewhat related to the soundstage adjustments made by the headphones themselves (the "BD earphone 8 Unit" can adjust four different soundstages), if it is in the default setting, the sense of richness will be reduced by half, presenting a more relaxed and pressure-free listening experience. However, the sound structure will be looser, resulting in a loss of that gorgeous richness. This also means that many portable DACs will actually provide a relative improvement after use. For example, using the "Beam 3 PLUS" and the "BD earphone 8 Unit" to listen to the drums is not as enjoyable because the drum sound is somewhat blurry around it. I prefer drum sounds that are powerful and clear in layers. Therefore, I can choose another customized pair of headphones to match, but not everyone has such a large budget. Because of this, I hope that readers can rely on their own ears to listen. Without trying the combination, it is not clear whether it will suit their taste. Therefore, to avoid collisions, it is still recommended for everyone to try listening before making a purchase.

Bluetooth: The 3.5mm on Bluetooth end is limited by Apple's inherent restrictions and cannot support lossless audio. Therefore, there will be a loss of cohesion and subtlety in the sound, subjectively about 20-30%. Most people can hear this difference (except for those who consider themselves tone-deaf). In addition, if you are an iPhone user who cares about sound quality and uses high-end headphones, it is still recommended to use a wired connection because the 3.5mm "medium" gain on the Bluetooth end is lower than the 3.5mm "low" gain on the wired connection. However, it must be emphasized that the author is an iPhone user. If you are an Android user, the "Beam 3 PLUS" supports LDAC and APT-X HD, so don't easily equate the two!

As for the 4.4mm on the Bluetooth end, its performance is comparable to the 3.5mm medium gain on the wired connection, subjectively lacking about 5-10% of the details. But for iPhone users, being able to achieve this level of sound on the Bluetooth end is commendable, especially considering it is AAC. This also proves what some audio enthusiasts have said, that if you want to use Bluetooth and care about sound quality, you can only use an Android phone. However, as an iPhone user, the author is already satisfied with being able to hear this level of sound on Bluetooth (Apple fans can only endure!).

What about LDAC on Android? The 4.4mm output under LDAC is better than the 3.5mm medium gain on the wired connection for iPhone, subjectively about 5-10% better. The difference lies in the subtlety of the sound quality. Therefore, if you are an Android phone user, the 4.4mm output under LDAC can replace the 3.5mm wired connection. However, it goes without saying that if you want to unleash the full potential of a portable headphone amplifier, the Android system is still more friendly.