CraneSong HEDD: Reference levels for A/D tracking and D/A/D for outboard processing

[amathie]

I'm using both a Crane Song HEDD and an Apogee AD16x/DA16x Symphony system for tracking into a DAW (A to D) and for analog outboard processing during mixing (D to A, analog processing and back A to D into the DAW).

I'm trying to get a better grip on my gain staging. On the HEDD, a +4dBu analog input equates to - 12dBfs digital output during conversion (factory setting) so if my standard reference level is +4dBu there is 12dB of headroom before digital clipping. There are some trim pots on the back of the unit and I understand from Dave Hill that there are some internal jumpers that give further flexibility. How are others using the HEDD in this situation? Are you using a standard +4dBu reference level and being careful to reduce your crest factors to less that 12dB with compression and limiting whilst tracking, using a different nominal reference level or playing around with the possible alterations in internal calibration with the jumpers etc? The Apogee convertors can easily be calibrated from the front panel to a wide range of values, so there's no real problem in changing these to match the HEDD.

[KRStudio]

First make sure your references for Apogee and Crane are the same. Apogee ships with -16 reference. Get both units calibrated for the same thing. I set mine for -20. I use all outboard pres. If I run them at +4 out of my pre, I have clean headroom out, not causing any clipping on the analog signal. This will give me -20 dbfs in the digital realm with peaks around -10 dbfs. There is no stress in the analog or the digital signal. If you need to reduce clipping in the converter, turn your preamp down. Useing a compressor is fine, but getting used to proper gain staging is very useful for full, good sounding mixes. Have fun!

Jeff

[amathie]

Thanks Jeff,

Yes I plan to run the Apogees at +4dBu = - 20dBfs, thus giving headroom for safe tracking and trying to avoid any deterioration in quality in the analog path when running levels close to their clipping points. I'm not sure how easy it's going to be to get the HEDD set up to that. Removing the internal jumpers I believe simply applies a 6dB pad to the analog inputs; I'm not sure whether there is any way to change the conversion reference when going D to A. I'll check with CraneSong.