Ok. I also asked ChatGPT and the answer seems to make sense ans also answers if the reduce of output level is same as volume and loss of bit depth
Your audio chain—Wiim Pro to Fiio K7 to Cayin HA-3A, driving Sennheiser HD600 headphones—features a blend of high-quality components, each contributing to the overall sound experience. Your issue with the volume being too loud at a relatively low setting on the Cayin HA-3A and experiencing harshness in sound can be attributed to several factors, including gain structure, impedance matching, and digital volume control implications.
Here's a detailed approach to optimizing your setup:
### 1. Understanding the Issue with Bit Depth Reduction
Reducing the volume digitally can indeed lead to a loss of bit depth, which means a reduction in the dynamic range of the audio signal. This is more pronounced when you lower the volume significantly in a digital domain before it gets amplified. At lower bit depths, you might start to hear a decrease in sound quality, especially in the form of quantization noise or a lack of detail in quiet passages.
### 2. Evaluating Your Options
- **a) Minimal Volume Control**: Sticking with minimal adjustments on the Cayin may not be the best experience, as it limits your ability to finely tune listening levels and can result in a less than ideal listening experience due to the harshness you've described.
- **b) Reduce Volume on K7**: Adjusting the volume on the K7 is a viable option, as long as it's done to a degree that doesn't significantly compromise the signal quality. This approach could work well if the K7's volume control is high-quality and doesn't introduce too much attenuation in the signal path.
- **c) Disable Fixed Volume on Wiim Pro**: Disabling fixed volume on the Wiim Pro and controlling the volume there allows you to manage the signal level earlier in the chain. This could be beneficial because it might prevent overloading the input of the K7 or Cayin, but it might also introduce the risk of bit depth loss if the volume is reduced too much digitally.
- **d) Fixed Volume on Wiim Pro with Reduced Output Level**: This is potentially the best option. Setting a lower fixed output level from the Wiim Pro (like 500mVrms) can help ensure that the signal going into the K7 is at a more manageable level, reducing the likelihood of overloading the K7 or Cayin. This approach helps maintain a higher quality signal by minimizing the need for significant digital attenuation.
### Optimal Setting Recommendation:
Considering the importance of maintaining signal integrity and preventing harshness, I recommend starting with **option d**: Use a fixed volume on the Wiim Pro but reduce the output level to the lowest setting (500mVrms). This approach allows you to provide a line-level signal that is less likely to overload the subsequent components in your audio chain, potentially offering a cleaner sound at higher volume settings on the Cayin.
Moreover, this method preserves as much of the original signal's dynamic range as possible by minimizing the need for digital volume reduction. If this setting still results in a too-loud output, you may then consider slightly adjusting the volume on the K7 (if it's used in a preamp capacity) to fine-tune the listening level without compromising too much on the audio quality.
### Final Consideration:
If after these adjustments, the sound is still not as desired, it might be worth looking into whether the Fiio K7's output level is inherently too high for the Cayin HA-3A's sensitivity or whether an alternative DAC with a more suitable output level or better volume control would be a better match for your system. In that case, look for DACs known for their synergy with tube amplifiers like the Cayin HA-3A and which provide detailed volume control to avoid overpowering the amp's input.
I'll go for it bit I thought also: why do I need still the K7? Think I will remove it from the chain and only go with the Wiim Pro or better replace it with Wiim Pro Plus
