Which Dolby for studer A 80

[Riccardo]

Originally Posted by dcollins

Get a 363 with 300 modules.


DC

Just out of curiosity how does it compare with the ANT Telcom C4?

[dcollins]

Originally Posted by Riccardo

Just out of curiosity how does it compare with the ANT Telcom C4?

I have only seen one C4 tape in 20 years. I rented a decoder and it sounded fine. Never had a fair comparison between it and Dolby. By all accounts it was a good format (potentially better than Dolby) but never seemed to catch on, especially in the colonies.


DC

[wado1942]

If i mix so that my peaks in the DAW are reaching -0 dbfs and i want to mix to SM 468 which is +12 db at 320 nW/m at 15 Ips , i have to calibrate my deck so that when i play test tone from the tape at 320 nW/m into my DAW i have to read - 12 dbfs level in my DAW right ? And you call this + 6 alignment of the deck right ?

OK all this "+6, +9" stuff is more or less meaningless. For instance, I align my decks to 400nWb/M, not "whatever dB". 400nWb/M tape fluxivity will show 0dB on all my meters. When you order your MRL tape, just order a 320nWb/M or 250nWb/M or whatever you want and don't worry about what tape recorder engineers in 1956 would have called it. The reference fluxivity you use in relationship to the DAW is also irrelevant as long as you ensure the output comming off the tape is appropriate to avoid clipping on the way into the DAW. I'd suggest finding out what the 3%THD level will be for your tape of choice and pick a fluxivity 16dB below that (400nWb/M on GP9 gives me 16dB of headroom before reaching 3% THD). Then set a -20dBfs 1K tone to read "0VU" on the tape recorder. That should allow you the choice of saturating the tape or not but avoid clipping in the DAW.

[bob katz]

Originally Posted by wado1942

OK all this "+6, +9" stuff is more or less meaningless. For instance, I align my decks to 400nWb/M, not "whatever dB". 400nWb/M tape fluxivity will show 0dB on all my meters. When you order your MRL tape, just order a 320nWb/M or 250nWb/M or whatever you want and don't worry about what tape recorder engineers in 1956 would have called it. The reference fluxivity you use in relationship to the DAW is also irrelevant as long as you ensure the output comming off the tape is appropriate to avoid clipping on the way into the DAW. I'd suggest finding out what the 3%THD level will be for your tape of choice and pick a fluxivity 16dB below that (400nWb/M on GP9 gives me 16dB of headroom before reaching 3% THD). Then set a -20dBfs 1K tone to read "0VU" on the tape recorder. That should allow you the choice of saturating the tape or not but avoid clipping in the DAW.

It is the peak level of the material that will tell you if you are near saturation of the tape, as the tape saturates on the peaks well ABOVE 0 VU. What Steve is effectively saying by his last three sentences is that if you are transferring to tape from the DAW with his -20 dBFS alignment----that the DAW should not necessarily hit full scale, and if you want a conservative tape level with little saturation, then with the above alignment, a peak level of -4 to -6 dBFS in the DAW may be appropriate. If you have to adjust the level of the file you're feeding to the DAC, it wouldn't be a bad idea to apply 24 bit dither, it certainly won't hurt and will help in a subtle manner.

You always have to listen because some material benefits from your hitting that 3% ceiling and other material does not. Another way of doing this is after aligning the digital to the analog the way Steven mentioned, just to use the VU meter on the machine the way God intended and ignore the peak meter. Chances are it will work just fine. On most material, if the VU meter is pinning, you're probably too hot.

[bass man]

Originally Posted by bob katz

It is the peak level of the material that will tell you if you are near saturation of the tape, as the tape saturates on the peaks well ABOVE 0 VU. What Steve is effectively saying by his last three sentences is that if you are transferring to tape from the DAW with his -20 dBFS alignment----that the DAW should not necessarily hit full scale, and if you want a conservative tape level with little saturation, then with the above alignment, a peak level of -4 to -6 dBFS in the DAW may be appropriate. If you have to adjust the level of the file you're feeding to the DAC, it wouldn't be a bad idea to apply 24 bit dither, it certainly won't hurt and will help in a subtle manner.

You always have to listen because some material benefits from your hitting that 3% ceiling and other material does not. Another way of doing this is after aligning the digital to the analog the way Steven mentioned, just to use the VU meter on the machine the way God intended and ignore the peak meter. Chances are it will work just fine. On most material, if the VU meter is pinning, you're probably too hot.

Bob , why do i need to dither if i am playing the file from my DAW to tape recorder ? Should i apply the dither only if i am adjusting my levels in the DAW ( in most cases reducing the level ) going into DAC or always ? Whats the benefit of that ?

Thanks

[bob katz]

Originally Posted by bass man

Bob , why do i need to dither if i am playing the file from my DAW to tape recorder ? Should i apply the dither only if i am adjusting my levels in the DAW ( in most cases reducing the level ) going into DAC or always ? Whats the benefit of that ?

Thanks

Deciding on 24 bit dither or not is the smallest possible issue anyone could argue over, so let's just talk the technical and then not worry too much about it: If you do any change in level, or process or EQ on the way out to the DAC, then technically you should put 24 bit dither on the output bus. The benefit is a very subtle reduction in distortion and increase in depth. Save this for another day if it takes you more than 10 minutes to understand or deal with this issue. As I said, at 24 bits this is kind of an audiophile-level difference, not a world-shattering one. Whether you can even hear that difference through the analog tape machine is yet another question!

Some things you just do because it's technically correct, if you can engage it quickly and then stop worrying about it. Otherwise, just stop worrying :-).

[wado1942]

Funny you mentioned dither, I realized that the piece of software I like most for simple level changes automatically applies flat dither upon output, whether to 24-bit file or playback. I had never really bothered to look into why it sounded better than other software, I just accepted it. There's probably more to it than that, but that's the most obvious trait I saw.

[bass man]

Originally Posted by Riccardo

Just out of curiosity how does it compare with the ANT Telcom C4?

I would like to know too ...

[Adam Dempsey]

Originally Posted by DC

By all accounts it was a good format (potentially better than Dolby) but never seemed to catch on, especially in the colonies.

(here in THE colony) I used to get mixes from an associated studio in which everything was mixed to MCI 1/4" 15ips C4 (then moved to PT, but I'm sure the C4's are still there). Also did 1/4" 2-trk dubs with a 4 channel C4 (2 channels switched to decode for direct monitoring), and the odd "layback" to Ampex AG440 via the same 4 ch unit.
Telcom C4, including the Telefunken cards I've used in Dolby frames, has always far trumped Dolby – any Dolby – in terms of NR and absence of artifacts. And no level calibration required. No pumping. Just clean. Originally devised for radio transmission noise reduction during WW2, it handles tape almost too easily.

[Riccardo]

Originally Posted by Adam Dempsey

(here in THE colony) I used to get mixes from an associated studio in which everything was mixed to MCI 1/4" 15ips C4 (then moved to PT, but I'm sure the C4's are still there). Also did 1/4" 2-trk dubs with a 4 channel C4 (2 channels switched to decode for direct monitoring), and the odd "layback" to Ampex AG440 via the same 4 ch unit.
Telcom C4, including the Telefunken cards I've used in Dolby frames, has always far trumped Dolby – any Dolby – in terms of NR and absence of artifacts. And no level calibration required. No pumping. Just clean. Originally devised for radio transmission noise reduction during WW2, it handles tape almost too easily.

Very interesting. We have two units in the studio for encoding and monitoring/decoding. They have been completely recapped and checked. I was curious as I have never had the ANT C4 and Dolby units side to side for a comparison.