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Transcript
Moderator: Dan, can you start by providing us with some background about yourself
and Metric Halo? P.Tucci: What tools do you refer to? Dan: Room analysis such as TEF and Audio Precision. Charlie Hughes: From a sonic performance standpoint, what sets the Mobile I/O apart from other digital audio/PC interfaces? Dan: Good question. Slew rate: very fast high-bandwidth op-amps.
Very good film caps in the signal path, fully balanced from input
to output, and very high headroom. In a nutshell, this is what really
sets it apart. On the digital side of things we're using very good
24/96 converters, but a lot of people do that. We really paid much
attention to the analog path as Moderator: How different have you found the hardware business? Dan: Much. It's the first time we haven't had everything completely under our control. Moderator: I would think its much more logistics intensive. Dan: Exactly. With software you have the luxury of being able to build your own bits. With hardware, first you have to conceive of a design and then you have to see if you can actually buy any of the parts. And then you have to see if you can buy any of the parts for a price that will allow you to sell the device for a reasonable amount of money. P.Tucci: I don't know how many of us are "Spectra fluent". What questions does SpectraFoo answer? I've seen the phase trace and the Transfer function. What else? Dan: SpectraFoo shows you everything you can hear and what you can't. There's level, phase, spectrum meters, and the unique Phase Torch, which shows phase as a function of frequency. Some of our customers have called it a "Swiss Army Knife" for audio. Moderator: It has a very "standard looking" O-Scope display. Dan: It also incorporates all the metering standards. Plus, you can make your own settings. P.Tucci: Would you explain your Phase Torch idea? Dan: The center of this polar-type display refers to DC, or 0 Hz. The outer perimeter shows you the Nyquist frequency, usually 24kHz. This meter takes two input channels, so signals that are perfectly in phase appear as a straight line from the center to the 12 o'clock line. By contrast, two signals that are exactly out of phase will appear as a straight line from the center to the 6 o'clock spot. Moderator: Meaning 180 degrees? Dan: Precisely. Typical stereo content appears as a fountain shape from the center. Higher frequencies would, of course, be spread into different phase vectors. Moderator: Dan, what is Nyquist frequency? Dan: The Nyquist frequency is most generally defined as half the sample rate, or half the frequency of sampling. Mark F.: What are the minimum hardware requirements to run the package? Dan: SpectraFoo runs only on Macintosh, and that's the most important one, but you can do just fine on a 604e (9600) at 180 MHz, no problem. Any new machine will do just fine, but there is a caveat about audio I/O. chat.boy: How about OSX? Dan: Not yet. Stay tuned! Charlie Hughes: Any plans to release a PC version? Dan: There are plans, but no projected release date for "FooPC". Charlie Hughes: What can you relate, sonically, to the display of the Phase Torch? Dan: The Phase Torch is most useful in a situation where you're dealing with linear delays, such as multiple microphones on a single source or a tape head. It can also tell you if the audio material you're working with is mono compatible. Charlie Hughes: I assume that as long as everything is in quadrants 1 & 2 (upper half of display), it is mono compatible. Dan: Exactly. It can save you a lot of headaches! P.Tucci: Can you compare your Phase Torch to another leading brand? What would leading high frequencies look like on your product? Dan: To answer the first question, there is nothing like the Phase Torch to my knowledge. And, regarding your second question, do you mean early arrival of a high frequency? P.Tucci: Correct. I'm thinking SMAART www.siasoft.com shows that as an up angle in the high frequencies. What would the same condition look like on Phase Torch? Dan: First of all, in the transfer function view, SpectraFoo Phase Torch will show that shift the same way as SMAART. The display is basically like taking the Cartesian display from the transfer function and wrapping it on a circle. So what you'd see is on the Phase Torch is a spiral. Moderator: Can we have an overview of what ChannelStrip does? Dan: ChannelStrip is the essential signal processing that you'd expect to find on a professional console: gate, compressor and EQ. We also added delay control. Moderator: ...back to our Phase Torch discussion. P.Tucci: The Cartesian is a frequency vs. phase view? Dan: There are two Cartesian displays in the transfer function view: frequency vs. phase, and frequency vs. amplitude. Moderator: Does ChannelStrip work as a "stand-alone" application? Dan: No. ChannelStrip is currently available only as a plug-in for Pro Tools TDM, Pro Tools LE (RTAS) and Digital Performer (MAS). Charlie Hughes: Have you been doing anything special with the clocking to minimize/eliminate jitter? Dan: Yes. We have a pretty novel PLL circuit that gives very good performance. We're looking at jitter on Mobile I/O in the 25-50 Pico second range. Charlie Hughes: Have you thought about buffering the output, like portable CD players do, to prevent skipping and then "re-clocking" it out? Dan: Yes, we can do that, but it depends on what the latency issues are. The DACs that we use reject jitter up to 1 Nano second. Moderator: This will end our chat with Dan Metivier. chat.boy: On behalf of PSW, thanks for your time and sharing your knowledge, Dan. Dan: Thank you. My pleasure. Moderator: Everyone is invited into the Live Sound Chat room for "after chat". chat.boy: The chat was moderated and organized by Dave Dermont,
"Another Dave". |