Next demo will be at woodsyi's on Sunday afternoon with the RevD unit in comparison to his RevC. This should be another fun afternoon of listening trials.
Last night I had Scottdazzle over and we were checking out my updated digital front. I got my micro Rendu hardware and firmware updated to 1.4 and got my EMM DAC2x updated to v2 which allows it to handle 2x DSD over DoP. Anyway we are listening and felt the mid-bass lacking. I was attributing the brightness to the newness of the updated electronics but it's been running for a week continuously. So I went into my digital crossover setup via, Audio Weaver
, and checked the output on my midbass woofers. They were set -4db. It's the setting Rich and I figured to be the best as the RM40 speakers have a tendency to boomy in the crossover region - 4th order 80hz highpass and 1st order 309hz lowpass in my case -- with the overlap from the ribbons with 1st order highpass at 309Hz. We settled on +2db after overshooting and making it sound too dark. At +2db the male vocals from The Band filled in and both Mark Knofler and Emmylou Harris from All the Roadrunning sounded just right. Then we listen to vinyl to see if the bass is too much on analog source and the balance was still good at +2db. So the change was not needed for just the digital end. What happened?
I got to thinking why and then voila!
I remembered that I just recently inserted this isolation transformer
between the eAR 1001 monos and the midbass woofers. I was getting a little ground loop hum from those woofers that I could not get rid of completely for a long time and this finally fixed it. Apparently it also reduced the output gain by 6db.
Add back the 6db gain and everything was good again.
It's one of the virtues of dspMusic to be able to adjust poles, slope and gain on each channel. It absolutely came in handy. At some point in my audio journey I will probably go to a simple solution, but I have to tell you I love the on-the-fly ability to adjust each driver on an active crossover system. It does time delay on my rear subs to smooth out bass too. dspMusic is really good with bass management.