Sound Devices 744T 24-Bit Workflow - Assistance Requested

[Dan Keaton]

I recently received my 744T and I am very pleased with it. (It has version 1.60 firmware loaded.)

I am testing the operation and use of this unit at this time.

I am able to record both 16-bit and 24-bit files at different sample rates and playback the files within the 744t without a problem.

I am also able to transfer the files to my editing computer via firewire without any problems. In fact, this is very easy to do.

With 16-bit 48,000 samples per second files, I am able to play the files in both Vegas and Windows Media Player.

However, when I record 24-bit files, also at 48,000 samples per second, I can not play them in Windows Media Player, nor can I play them successfully in Vegas 6.0b.

In Windows Media Player, I receive an "Unknown Error" when I attempt to play the 24-bit files. I do not know if Windows Media player can handle 24-bit files.

In Vegas, I can place the 24-bit files on the timeline and see the audio peaks properly. But, when I play the files they are distorted. The "Properties" states correctly that the input files are 24-bit and 48,000 samples per second.

In the 744t, and when I transfer these files to the editing computer, these files have the ".wav" extension and not the ".BWF" (Broadcast Wave File Extension). This is a setup option on the 744T which just changes the file extension but does not alter the contents of the file.

Any suggestions would be appreciated.

I hope I placed this in the correct forum, I choose Audio instead of Vegas.

[Steve House]

Just wild guesses here, perhaps DSE will chime in with first-hand knowledge, but in the meantime a few things I'd check ... What is the bit depth setting in the project properties in Vegas? Are you sure your audio interface or soundcard handles 24 bit playback?

Vegas is up to version 6.0d now, just FYI. Don't know if that has any bearing on your problem but it's worth checking into. Do you have any other audio applications you can try the problem file in?

BWF files actually are supposed to have the ".wav" extension and generally do - saving with a ".bwf" extension is incorrect according to the official file specification. BWF is a normal wave file with added information in the file header.

I just recorded a 48kHz, 24-bit test file and saved copies in both standard wave and BWF formats. Windows Media Player 10 and Vegas 6.0d opened both and played them just fine.

It brings incredibly bad luck to own a 744T that sounds garbled in Vegas. Among other things it attracts tornados to your house. Luckily I am immune to its evil eminations so for your own protection I suggest you box it up and mail it to me immediately for proper disposal <g>.

Congrats on the new toy <g>

[Dan Keaton]

Dear Steve,

I matched the Bit-Depth setting in Vegas to the source file bit-depth. I also tried other settings. I also checked the "Mixer" panel to ensure that the bit-depth settings were correct.

Thank you for the suggestion and assistance.

[Seth Bloombaum]

The upgrade from 6.0b to 6.0d is free if you're registered. b to d fixed many bugs, don't know if this was one of them. I think 6.0c was out by the time I upgraded, I had no problems with importing 24/48 744T files other than needing to split them from polyphonic to mono files.

If I remember, you're recording bwf on the 744T, whether you've selected bwf or wav extension. As Steve mentioned, bwf can have a wav extension. It really is just a variant of wav with more header info and optional multiple channels.

A great swiss army knife audio app that is free is Audacity, get it from audacity.sourceforge.net. It opens mono or stereo bwf. As you're probably aware, you need bwf splitter from fostexdvd.net for four channel files to split the files.

Then, the proper way to bring in a bwf, with extension bwf or wav is via file | import | Broadcast wave...

Having said all that, if your waveforms are displaying, that would seem to indicate some issue with the sound card. Can you leave the 744T out of the equation and just record something in 24/48 that plays back? If not,... does your sound card do 24 bit? What is it?

[Dan Keaton]

I will download and install Vegas 6.0d. I was editing a movie last year when 6.0c and 6.0d came out. Since 6.0b was stable, I errored on the side of caution so as to not interfere with the tight editing schedule.

I will download Audacity and give it a try. I was originally attempting to determine if I had a Vegas or 744T problem.

My original files were recorded as "Polyphonic" (multiple tracks in one Broadcast Wave File), with the .wav extension.

Based on your suggestions, I recorded a 24 bit file as a "Monophonic" BWF (One track per file). Then I imported this into Vegas 6.0b and it worked great. Of course, I set the Vegas project to match the 24 bit depth and 48,000 samples per second.

While I was performing this test, I recorded the file as a ".BWF" instead of a ".WAV". Vegas 6.0b, in the explorer, does not see the see the ".BWF" files. So I changed the extension to ".WAV" and it worked fine.

My appreciation go to Steve and Seth for their assistance. I was not aware that I needed to split the polyphonic files into monophonic files for the import into Vegas.

[Dan Keaton]

Dear Seth,

I downloaded Audacity and the BWF Manager from FostexDVD.Net.

The BWF Manager (Polyphonic BWF File Splitter to create Monophonic BWF Files) was just what I needed.

Thank you for all of your assistance.

In listening to the original polyphonic BWF in Vegas was very interesting. I would have never guessed that the sounds that I was hearing were due to the file being "Polyphonic" and Vegas could not handle it. At first, I thought that I had a bit-depth or sample rate issue.

This was very eductional.

[Dan Keaton]

[QUOTE=Steve House]
It brings incredibly bad luck to own a 744T that sounds garbled in Vegas. Among other things it attracts tornados to your house. Luckily I am immune to its evil eminations so for your own protection I suggest you box it up and mail it to me immediately for proper disposal <g>.

Dear Steve,

Thanks for your help.

Since the 744T was never evil, it was just a mistake on my part, I feel that I will not need to send it to you. <g>

On a more serious note, I find the unit to be very well designed, as expected from Sound Devices. I had read the manual prior to purchasing it and I thought the learning curve might be steep. However, I found the unit easy to understand and use, but of course I have not utilized all of its features yet.

If you read the manual beforehand, you can be recording within 5 minutes of opening the box.

[Steve House]

I'm wondering, as long as you're experimenting, what happens when you record a 2-channel stereo BWF on the 744 instead of the 4-channel polyphonic you had tried. Do you still have to split it into separate mono files before importing to get proper playback?

[Dan Keaton]

Dear Steve,

Very Interesting Question!

I set up the 744T for BWF 2-channel stereo polyphonic recording:

Menu Item 4 - Record File Type: ".wav Poly"

Then I set up

Input 1 to Track A
Input 2 to Track B
no inputs assigned to Tracks C and D to ensure that this would only be a two channel recording.

This should create a stereo (or two track mono) file.

I recorded a take, connected to the computer via firewire, copied the file to a file on the computer and opened Vegas 6.0b.

The take sounded fine, it worked!

So it appears that you do not need to split two-channel polyphonic files into monophonic files.



Now this is getting interesting.

If you record four channels, in polyphonic mode on the 744T you will obtain one output file.
If you record in monophonic mode, you will obtain four files.

I wonder if there is an easy way to split a four channel polyphonic file into two two-channel polyphonic files?
I feel that this would be a nice feature for Vegas if it does not handle this already.




By the way: Earlier, when I was using Vegas's Explorer window, I did not see ".BWF" files. I found an option, in "Views" in the Explorer window, "All Files", which will show these files.

[Steve House]

Originally Posted by Dan Keaton

Dear Steve,

Very Interesting Question!
...
By the way: Earlier, when I was using Vegas's Explorer window, I did not see ".BWF" files. I found an option, in "Views" in the Explorer window, "All Files", which will show these files.

As mentioned before, the extension of BWF files isn't always ".bwf." In fact, the formal BWF files specification calls for them to have the ".wav" extension and so you'll find them either way, depending on the application that generates them.

[Dan Keaton]

Dear Steve,

I agree. Sound Devices makes in clear in their manual that the standard is ".wav" and not ".bwf" and that the only difference is in the extension created on the file.

During my testing when I created ".BWF" files, I was initially concerned that Vegas did not even show these files in their Explorer window. I later learned about the "Show All Files" option.

I am using ".wav" files for normal work. I assume that the ".BWF" is for compatability with another system.

[Steve House]

Originally Posted by Dan Keaton

Dear Steve,

I agree. Sound Devices makes in clear in their manual that the standard is ".wav" and not ".bwf" and that the only difference is in the extension created on the file.

During my testing when I created ".BWF" files, I was initially concerned that Vegas did not even show these files in their Explorer window. I later learned about the "Show All Files" option.

I am using ".wav" files for normal work. I assume that the ".BWF" is for compatability with another system.

Here's a link to a good technical rundown on the BWF file format
http://www.ebu.ch/en/technical/publi...user_guide.php