Werner Althaus Posted October 20, 2015 Report Share Posted October 20, 2015 (edited) I just took posession of a 664 and am a bit confused about the menu options. In the 442 and 552 that I use I have the option to calibrate the tone level (defaults to 0dBu for reasons unkown to me) AND the meter reference level (also defauts to 0dBu=0VU).I set all our mixers to tonelevel =+4dBu, meter reference level 0VU=+4dBu. With the 664 this seems impossible. The tech support person @ SD didn't really underrstand my concerns so I was wondering how to best deal with this. Recalibrate all out SD mixers to 0dBu = tone= 0VU? I know the output of the 552 is a max of +20dBu but we've never had any issues with the output limiters set to +17 dBu (honestly I thought they were kicking in at +17VU which would be +21dBu in our setup) Again, in my world -20dBFS = 0VU = +4dBu = 1.23Volts Edited October 20, 2015 by Werner Althaus Quote Link to comment Share on other sites More sharing options...
BAB414 Posted October 21, 2015 Report Share Posted October 21, 2015 I think you *might* be confusing the numerical layout on the screen. I believe the meters on the 664, though it is a digital recorder, are in analog dBu, not dBFs. Does that make any sense with regard to your issue? Quote Link to comment Share on other sites More sharing options...
Mungo Posted October 22, 2015 Report Share Posted October 22, 2015 Zero is 0 dBu on the analogue outputs equal -20 dBfs on internally recorded files and the AES outputs. It's not possible to change anything. That's a mess for us here in Europe because EBU has completely different recommendations. Quote Link to comment Share on other sites More sharing options...
Werner Althaus Posted October 22, 2015 Author Report Share Posted October 22, 2015 (edited) Heard back from Matt@ Sound Devices. "Let me step through a few things on the 664:-The maximum analog output level is +20dBu. -This corresponds to 0dBFS, and is not adjustable. -This of course implies that -20dBFS = 0dBu. Because of this, it is not possible for -20dBFS to correspond to +4dBu; this would imply a maximum analog output level of +24dBu, which is beyond what the voltage rails of the 664 will allow. We have for quite some time now shipped all of our units with defaults of 0dBu = 0VU, as this was requested over and over again from customers. It somewhat flies in the face of convention from years ago of having 0VU = +4dBu or +8dBu, but then again, as electronics have gotten quieter in real world situations this arbitrary reference has become less relevant". Not sure I like what I hear but at least I know what's going on. Also asked about the 0dB pan-law and got this: "The panning really comes from how most of our customers use the product. Most are not recording music, and don't use the pans like "real" pans - rather they hard pan L, C, or R simply as a bus assign really. In those situations, it is easier for them to deal with the gain not changing as they pan." Makes me wonder why they didn't just use a routing switch (LCR) and sae on real estate. Other than that it a fabulous mixer. I took it out for a 6 microphone multicamera shoot yesterday and the results were great, really like the preamps, huge improvement over 442, and the unit is so intuitive it hurts:) Edited October 22, 2015 by Werner Althaus typo Quote Link to comment Share on other sites More sharing options...
Werner Althaus Posted October 22, 2015 Author Report Share Posted October 22, 2015 (edited) I think you *might* be confusing the numerical layout on the screen. I believe the meters on the 664, though it is a digital recorder, are in analog dBu, not dBFs. Does that make any sense with regard to your issue? No, it doesn't. The 664 meters use an analog scale with 0VU = -20dBfs. They should have done 2 things, IMO. They should have designed the I/O to handle +24dBu at minimum and they should allow the digital reference to be selectable (at least include -18dBfs as an option) A VU style meter doesn't show dBu, it shows dB relative to a reference level with 0VU =reference . That reference level used to be -10dBv for consumer gear and, +4dBu or +8dBu for prolevel gear, then Mackie and some others started this 0dBu=0VU thing years ago. It might be a costcutting measure since it brings the requirements on the analog I/O closer to the range of consumer gear. In the end it makes sense to preserve 20dB of "headroom" by moving the reference level to a point that's 20dB below the maximum analog output but then it's not really a reference level anymore, I mean, why not use -6dBu as =0VU on an XLR output? I used to not even consider equipment purchases where, at +4dBu, the analog I/O doesn't equal or exceed the artificial digital headroom set by the agreed upon digital reference of -20dBfs (-18dBfs in Europe) but my guess is that those days are over. Edited October 22, 2015 by Werner Althaus Quote Link to comment Share on other sites More sharing options...
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