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Old October 25th, 2002, 01:55 PM   #1
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Inependent Audio Setup - Notebook PC HD or DAT?

I am trying to figure out what type of independent audio setup makes the most sense for documentary shooting (mostly inside interviews and narrative voice overs). This is for a PBS-level broadcast quality project.

I am particularly intrigued by the idea of using my notebook computer with some kind of pre-amp/mixer and a high quality shotgun mic. My biggest question is can this achieve the sound quality of DAT which seems to be the best alternative for high quality.

The only preamp/mixer that will feed into my notebook that I am aware of is the USBpre (www.usbpre.com), are there others or could this deliver DAT quality to my hard drive?

Also, anyone know how much *uncompressed* audio recording time I could get per gigabyte of hard drive space?

Thanks!
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Old October 26th, 2002, 08:58 PM   #2
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The USBPre is capable of very high quality audio. If used in 24bit mode it should be sufficient for the type of work your proposing. The S/PDIF output can go to a DAT as a backup. This page shows you the data rates for audio.http://www.usbpre.com/datarates.htm Depending on the quality you desire your going to be between 10 to 33 MB per minute of audio.

Jeff
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Old October 26th, 2002, 10:32 PM   #3
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Jeff, thank you! That is excellent news.

It looks like (from the link you posted) that a dedicated USB 1.1 slot can handle USB Pre's maximum quality signal of PCM 24-bit/96k stereo. Am I correct in assuming that since the analog to digital conversion occurs in the USB Pre that the data transfer (in digital) from USB Pre to the Hard Drive will occur with no quality loss at all?

I have also read that the 16-bit/44.1k in the pd150 and comparable camcorders is somewhat misleading because of the cheap components used, thereby producing noise and other problems that can be overcome within the 16-bit/44.1k range. Do you have any idea if the USB Pre is built with higher quality components such that if it is recording in 16-bit/44.1k it will have a higher quality sound than a pd150 or XL1s?

And finally, if I record on the max quality (24-bit/96k), can I bring that into the NLE timeline and sync it up as is with max audio quality, then when it writes to DVD will just become 16-bit/44.1k? Or do I need to record in 16-bit/44.1k if I plan to edit in an NLE and ultimately write to DVD (for personal distribution) or tape (for broadcast master)?

Just want to get the max quality sound -- I hear that some broadcaster have very high standards for audio. Thanks a ton!
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Old October 26th, 2002, 11:55 PM   #4
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Quote:
And finally, if I record on the max quality (24-bit/96k), can I bring that into the NLE timeline and sync it up as is with max audio quality, then when it writes to DVD will just become 16-bit/44.1k? Or do I need to record in 16-bit/44.1k if I plan to edit in an NLE and ultimately write to DVD (for personal distribution) or tape (for broadcast master)?
most NLE programs will downconvert to the type of project you have open. I am fairly sure some like vegas video being a native sound program will allow you to edit with totally uncompressed audio, then downcovert to a compatible format to what you are exporting too.

don't be mislead by the 'digital' thing, especially when it comes to audio. Just because it is digital does not make it suddenly better. There is ALWAYS a loss when going from analog to digital, just whether it is audible (which most people would never know unless they had the original source there, and still most can not tell) is another story.

Remember one form is a pure soundwave that is being recorded, the other is an interperated digital bit, that is sampling. 24 bit is far far better at masking this as it almost has enough sampling to replicate an analog source.

The reasoning people equate digital with better comes from 2 different sources.
1. marketing, everything digital must be better due to hype.
2. it is far easier and cheaper to receive a better result with digital than with analog, but that still dosn't make it better, just easier for most.

There is a reason nearly all top recording artists are going or have gone back to analog equipment from the early 1980's, because simply it has far great range and fidelity. But to put it simply, a well pressed record will kill the same record mastered on a cd, but to achieve that you would need to spend at least 20x as much on the equipment vs plugging in a $200 cd player.

Anyways that was my rant, because i am getting a little tired of the assumption that digital must= better especially with sound, if i could have my choice i would have a good 24 track master tape recording deck with my always on set, the sound that can achieved in those is something that really is amazing. But the size and cost makes it impossibe.

kermie

ps. most of what i have said here deems no relevance, and i am sure some will disagree, but people who have used a lot of the top end older equipment, and worked with it know what it is truely capable of.

kermie
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Old October 27th, 2002, 01:33 AM   #5
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Thanks Kermie, I certainly trust you on the analog thing. I just want to do the best digital sound possible for the master (after all NLE cutting), ideally downconverting for each final format at the very end as necessary. Glad to hear Vegas Video can do uncompressed (24-bit?) audio well, as that is what I am editing on.

And is it not correct that once a sound is in digital form (regardless of its quality), transferring it through the USB pipe maintains 100% of its quality, or can the quality of digital still deteriorate while going through the USB port?

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Old October 27th, 2002, 01:57 AM   #6
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There are 2 camps on the digital thing.

But seriously, bits are bits, with digital it is all or nothing.

Unlike analog when you get degradation in the signal, with digital you either have it all, or dead air (silent) so no probs with the USB thing.

Don't quote me with the vegas video thing, but i am almost positive it does, you make have to specify it is an our of spec audio type in the properties of the project.


kermie
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Old October 27th, 2002, 05:09 AM   #7
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Brad,

The USBPre is of excellant quality. I use several Sound Devices products and the quality and construction are superb. You might pose the Vegas Video (audio) question in the PC editing forum http://www.dvinfo.net/conf/newthread...ead&forumid=31 We have lots of VV3 users in the community.

Jeff
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Old October 30th, 2002, 01:36 PM   #8
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After reading this thread, i want to be the naysayer. I've tried this setup, putting the USBPre into my laptop as production audio. Does it work? Yes. Does it work effectively? No. Why? It's too cumbersome and time consuming. I ended up trading my USBPre for an HHB Portadisc and haven't looked back since. If you're doing location work, you need location equipment. Unless your job allows you to be at that laptop the entire time, you'll be stumbling all over the production just trying to keep things afloat. It's not portable, and it's not location friendly. Getting a DAT or professional mindisc would be a much better option in that case, even though it's "lower quality." 24bit doesn't mean that much on location compared to good miking practices. Get what you need recorded through the mic, and let 16 bit be enough for you. Many, if not most, of the feature films in theaters in the last five years were recorded 16 bit DAT. It's not good enough for critical studio work, I agree. It's not good enough for U2 or The Stones. But on location for film or TV, bit depth is not as important as good production value. Take Star Wars for example. Episode 1 used 16 bit. Episode 2 used 24 bit. I didn't know that, and I bet neither did most. I only read it, I didn't notice it at all. I'm ranting, sorry, but hopefully you get the point. It's more effective to use the tried and true tools of the trade. Laptops are too hard to use.

However, if I had a spare 10 grand I'd be buying a 24bit Deva. They're sweet, and production friendly.

Devil's advocate,
Conrad
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Old October 30th, 2002, 02:55 PM   #9
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I agree with Conrad. The logistics of using the laptop would get to be pretty wearing esp. with a preamp hanging off it. One more thing to go wrong, get stepped on, etc. -- which is not what one needs on a docu shoot. Conrad is right on the mark with advice about good mikes and good miking practicies too.

I also have a Portadisc and like it a lot. The minidisc format is not quite as good as DAT, but for broadcast the quality difference is unlikely to be noticed much, if at all.

For a filim-making related review of the PORTADISC see:
http://www.lafcpug.org/review_mini_disc_rec.html
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Old October 30th, 2002, 03:12 PM   #10
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I think the suitability of using a laptop to record audio will depend on your crew. If your attempting to do your documentary with limited crew and equipment it will be much easier to use a camera or DAT to record audio. However, if your using a full crew and have a dedicated audio person or two I see no trouble with using a laptop.

In fact I've done productions where the audio and video were directly captured by desktop and laptop Macs. This was not done for a quality concern. In my case it was to save time. Between takes and during tear down the editor was working on the piece. This approach saved the client numerous hours of capture and editing that the time frame did not allow for. I see no reason the direct recording to laptop will not work given the proper crew support.

Jeff
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