< Burl Audio >
by Marc Alan Goodman
< Issue 84 >
There seems to be a new trend developing in audio converter design. Up until recently, engineers considered converters to be part of the digital or computer side of their rig as opposed to the analog side. Concurrently, just like the computers they’re directly connected to, converters become obsolete every couple of years, and their designs focus on advancing the handling of information on the digital side (better clocking and conversion). This began to change with the release of the Universal Audio 2192 (Tape Op #39) in 2003. For the first time, you could purchase a converter from a major manufacturer with a highly developed analog front-end.
When Rich Williams, who was the lead designer of the 2192, left UA, he had a goal: to build his converters without the restrictions placed by major manufacturers to keep the price down. Essentially he wanted to build the perfect converter, one with an analog side reminiscent of the best and most overbuilt tape machines, and a digital side to match. His initial releases in the B2 Bomber series (Tape Op #79) were sibling two-channel A/D and D/A units, but as people got wind of them, it became obvious that there was a market for a multichannel system.
The Mothership is essentially a complete modular computer interface. The rack itself is designed to accept Burl ADCs and DACs; MADI, AES, and Avid DigiLink I/O; monitor/control-room section; integrated mic preamps; and a more cost effective range of ADC and DAC cards designed for broadcast. Audio over Ethernet as well as USB control and metering are also planned. By integrating all of these components with a single internal master clock, the need for external clocking is eliminated. As of now, only the BAD4 and BDA8 are available. The BDA8 is eight channels of D/A conversion while the BAD4, which uses the same circuitry as the B2 Bomber ADC, is a beast of its own. It’s only four channels due to the fact that each one is transformer- balanced with a more (dare I use the word) burly front-end. This way, you can drive these A/D cards harder, like you would a tape machine, in order to get a different range of tones.
Assembly of the unit was a breeze. Blue Wilding from Audio Power Tools (www.audiopowertools.com) brought over a number of boxes containing the power supply, rack, and individual cards. The cards snapped into the rack in a self-explanatory manner. A short manual was included (which I noticed was printed out specifically for my system) but wasn’t needed. All I had to do was power it up and connect two DigiLink cables from my computer to the unit. Pro Tools recognized it via default settings, and I was ready to roll.
First thing when we received the unit, a few engineer friends and I sat down to give it some blind tests. We started with the DAC, focusing simply on listening to complete two-channel mixes through it. Comparing it to our previous rig, Apogee AD/DA-16X converters (Tape Op #59) with an Antelope Audio Isochrone OCX clock (#68), every person in the room could tell them apart every time. Not only did the Mothership sound significantly different, it sounded significantly better as we consistently picked it as our favorite. We went on to do some more complicated tests on the BAD4 and using multiple channels of the BDA8, as well as swapping between the clocks, but none of them were double-blind, so I won’t go into detail here. I can tell you that the Mothership came out the clear winner with no arguments.
The first session tracked with the Mothership was a band called Lost Boy. Daniel Schlett recorded it and gave me a full report. The frequency spectrum was totally balanced, but for the first time, gain-staging seemed to directly affect the tone of the converters. Sending a lot of level to the BAD4 would start to saturate things out in a fashion similar to a tape machine, while pulling back a bit would leave things even clearer sounding than our previous rig. Drum overheads ended up being recorded a tad quieter, while the guitars came in a bit hotter, which led the tracking to have more of a natural balance than was expected.
A few days later, I was able to give the BDA8 a more thorough run-through by remixing a song for the band Normal Love. I had done the previous mix on the same rig – out of Pro Tools, through our API 1608 console (Tape Op #81), through some outboard (very little was needed since I had tracked it myself), and back into Pro Tools. The only thing significantly different about the chain was the converters. This time, the mix just seemed to come together with very little effort. The bass seemed more extended, and the high end seemed clearer and less grainy, but the real difference laid in the lower mids. Suddenly, the 350 Hz-1 kHz range had far more three-dimensional depth than I was used to hearing. It was as if I’d put on 3D glasses, and the front-to-back range of the mix was pulled out like toffee. The kick drum, which I had to scoop out in that range on the first mix due to a bit of muddiness, suddenly had a punch to it that came forward and hit me in the chest. Moving things back-and-forth in the third dimension became simple, and the center image was strong and focused in a way I had never heard it before. Upon hearing my account, Rich explained that “the BDA8 uses passive filters for optimal phase response, hence the low mids sound right, the bottom goes to the floor, and highs sound correct instead of messy and chaotic”; and the Class A circuitry utilizes “discrete, custom BOPA2 op-amps for clarity in the middle.” He further clarified that “the BDA8 does get fatter/warmer as you push the output level”. At the end of the day, I compared the mixes, and we quickly decided to shelve the original. The new mix just sounded more alive, and more like music.
It’s rare to find a single piece of gear that elevates not only my entire studio but the way I work as well. Fancier gear can’t make you a better engineer, but more powerful tools can give you a larger palate to work with, and I feel like the addition of the Mothership opened Strange Weather to a new world of shades and colors. For the first time, it’s easy to see our converters as pieces of musical equipment rather than computer hardware, and I can’t imagine ever going back. (Mothership chassis and power supply $2499 MSRP, BAD4 $1399, BDA8 $1699; www.burlaudio.com)
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