For some time I've been wondering what kind of integrated audio ADC is included in
Blackmagic DeckLink Studio (and other BM products). For this test I used
RME Fireface UC audio interface for DAC and reference and
RightMark Audio Analyzer software.
Results are not definite truths nor professionally controlled and concluded. Further reading about RMAA caveats:
http://nwavguy.blogspot.fi/2011/02/r...yzer-rmaa.html
Balanced Cordial 60cm TRS cable was used for all tests. Balanced circuitry is said to be more noisy than normal, but I didn't want to redo everything to test a tiny change.
Baseline, RME external loopback (+4dB):
http://www.siluriformes.net/dfaq/AN3.../an34-an78.htm
RME (-10dB) -> BM (-10dB):
http://www.siluriformes.net/dfaq/AN3.../an34-bm12.htm
RME (+4dB) -> BM (+4dB):
http://www.siluriformes.net/dfaq/AN3.../an34-bm12.htm
RME ("HiGain") -> BM (+4dB):
http://www.siluriformes.net/dfaq/AN3.../an34-bm12.htm
RME (+4dB) -> BM (+4dB +4.8dB gain):
http://www.siluriformes.net/dfaq/AN3.../an34-bm12.htm
RME (+4dB) -> BM (+4dB +7.6dB gain):
http://www.siluriformes.net/dfaq/AN3.../an34-bm12.htm
As you can see I tried many types of level matching and it did do some good. Blackmagic control panel settings regarding the audio gain control gave weird results and when I chose to add for example +3dB, in reality the gain changed much less. With higher gain on Blackmagic end I could achieve better dynamic range up to a point. Well, you can see from the results what happens with too much gain. Pretty counter intuitive. As a side note; BM video gain controls also f-up the signal and like I've said before it's better to adjust levels after capturing than with BM's proc amp.
In summary I would say that Blackmagic Decklink Studio has good enough audio ADC for VHS and other home video formats but I would be a bit more careful when doing something more professional.
