Hiss is a common problem with most of today’s DSLR cameras. The front ends tend to be noisy which can lead to excessive hiss if the levels are not set right. The simple fact is that the higher the gain of the camera preamps, the higher the hiss. The solution obviously is to reduce the noisy gain in the camera and replace it with the very clean gain of our DXA-SLR or DXA-SLR PRO adapters. When no amplification is required as when using wireless mics, our low cost passive DXA-5Da can be used.
When using the DXA-SLR, adjust the level controls on the adapter so that the indicator LED’s flash green. This tells you when you are in the proper recording level window to get the best signal to noise ratio and least amount of hiss. On the DXA-SLR PRO, you can use the built-in VU meters as a guide and set the levels so that the audio is peaking at no more than -12 dB. Use the AGC Disable feature on the adapter to reduce the noise created by the AGC in the camera.
If your camera allows you to disable the AGC from the camera menu, you can use manual mode to get even better audio. On the Canon 5D MK II or MK III set the camera gain to 25% of maximum. On Nikon cameras set it to LEVEL 1 on the older models, or 7 on the newer D4 and D800. In this case, you do not need to use the AGC Disable feature on the adapter – keep the switch to the left so that it is not activated.
It is critical that the levels be set right so that you are not starving the camera for audio as that will increase the internal camera gain which is something you want to avoid. Once the levels are set correctly, you should be able to capture clean, crisp audio.