Topic: JB3 as lappie backup

[The Kilted Taper]

Just want to clarify something before I head out and tape tonight. I wanted to attempt my first pull with a lappie tonight. As it is my first try, I wanted to make sure I still got a usable copy. My rig is Nak 300's > WMod UA5. I was going to run at 24/48 as I've read that the 96 is not reliable at all times. Can I also send this signal to the JB3 via optical and get a listenable product? I know it cuts out the last 8 bits, but the FAQ states that a 96signal is just a big no no. And I'd prefer to send the JB3 a digital signal, but I could always send an analog signal just to make sure I got something.

[Scooter]

When i was first starting w/ my laptop i wanted to do the same thing.  I ended up going analog out to JB3, just cause of the truncation thing.  But i have given a patch out to a JB3 while sending a 24/48 sig to my laptop, and the guy said it worked out fine.  Obviously it was truncated to 16b...

[The Kilted Taper]

Yeah, the more I think about it, I may just play it safe and send the analog signal from the RCA's to the JB3.

[Brian Skalinder]

I'd recommend running analog out to the JB3, even though it means passing through A>D, D>A, and A>D again.  Based on a quick listen I did recently of a 24-bit WAV and the same WAV truncated (with s/w) to 16-bits, the truncated version didn't sound very good.

[sygdwm]

as long as you dont crank the levels on the jb3, the truncated version is listenable, but not ideal obviously. ime. ymmv.

[hexyjones]

as long as you dont crank the levels on the jb3, the truncated version is listenable, but not ideal obviously. ime. ymmv.

Are there any truncation demonstations out there? I truncate all the time but - I have no way of hearing what I'm missing...I dont dectect any anomalies - but it's something I wish I wasnt doing...if I could just hear it once(no matter how subbtle) - I might be driven insane to the point of buying new gear...

Also - is all truncation the same? - does a half-duplex signal truncate the same as a full-duplex?

[sygdwm]

ive a/b'ed some of my 24/48 recordings vs 16/48 jb3 backups, and i can tell the difference, but some of my friends cant. so, like i said it will work, but it is not ideal.

[Brian Skalinder]

Are there any truncation demonstations out there?

I don't know of any.  Here's what I did:

• downloaded a 24-bit / 48kHz track from the SD 722 / V3 comp posted fairly recently
• using CEP 2.1, saved the 24-bit file as 16-bit with no dithering, i.e. I assume the s/w truncated since I specified no dithering scheme
  
  • Edit | Convert Sample Type
  • Leave sample rate at 48 kHz
  • Set resolution to 16-bit
  • Disabled dithering
• using CEP 2.1, dithered to 16-bit and saved
• Edit | Convert Sample Type
• Leave sample rate at 48 kHz
• Set resolution to 16-bit
• Enabled dithering
• Accepted default dither bit depth (1)
• Set PDF to triangular
• Accepted default of no noise shaping

I found the differences readily noticeable, even over my office headphone setup:  PC digi-out > smART DIO > AKG K501, and I did not like what I heard in the truncated file.

Also - is all truncation the same? - does a half-duplex signal truncate the same as a full-duplex?

Not sure what you mean by half-duplex v. full-duplex, at least not in this context.  If people will chime in and let me know...

• what half-/full-duplex means in this context so I know whether or not I need to modify my process above
• that s/w truncation I performed is a valid way to set up the comparison (can't do it hardware based)
• that there's demand for the comp

...I'll BT a comp for everyone.

[Brian Skalinder]

ive a/b'ed some of my 24/48 recordings vs 16/48 jb3 backups

Duh.  Better than my offer to post my s/w-derived comp, are you willing to host a comp, Dre?  Or deliver some A/B files so I can host the BT?

[sygdwm]

sadly, since i only use it for backup, i never keep the jb3 files. sorry.

[Brian Skalinder]

sadly, since i only use it for backup, i never keep the jb3 files. sorry.

Ahhhh, rats.  Makes sense, though.  Have any shows coming up from which you'd be willing to pass along files for the comp?

[sygdwm]

i just sold my laptop-based rig to fund 1/2 a 722. im not sure ill keep the jb3 much longer.

[hexyjones]

Darn! - Is anyone else able to perform this feat?

I'd definitely be interested in hearing a JB3 truncated 16 vs. Straight 24 comparision.

I don't doubt there is a difference - but I'd like to get some idea of the effect...subtle, pronounced? just curious...

[The Kilted Taper]

I'll just add this in, I'm glad I had the JB3 as a backup last night, even with the analog in. I knew the battery on the lappie wouldn't last the whole show, but I being greedy and wanted to let the song finish before I stopped and saved. Less than 1 minute till the end of the song and I loose the lappie. Oh well. It "appeared" that Soundforge was working (not sure if it was this thread or another UA-5 lappie thread that someone wasn't sure SF would work). May get another chance to test next week if I am not working Thursday night, if not I don't have anything for a while.