Tape sync questions

[Brian Roth]

Does anyone recall specialized 1" machines referred to as a "layback" deck? They were used to "lay back" an audio track onto 1" C-format video tape. Special record head that could allow a "sweetened" audio mix to be recorded onto the small sized space on the edge of the video tape. The decks ran at an odd speed (8.something IPS as I recall).

In early 1990's, before our company went Full Blown Avid for in-house video post, we used an outside place for dealing with video projects. They had a MCI layback 1" machine. Our facility and theirs had 1/4" center stripe machines for moving audio elements back and forth. Of course, SMPTE everywhere <g>. We had a Microlynx in our studio that did a great job with our MTR-90 24 track, Sony 3/4", ProTools, the aforementioned Otari MX-55 center stripe machine and some other "partridges in pear trees".

At one point, we also had DAT machines and a Fostex ADAT machine with timecode facilities to handle various formats when dealing with outside audio facilities.

Bri

 

[EmilFrid]

Hello EmilFrid,

To get a 100% reliable synchronization system, there is only one word : RESOLVE.

That's what " aurt " is saying in his previous post, and he clearly explains the process.

ALL machines ( whether tape recorder, video player, DAW, TC generator ) must have their clock / capstan / slaved and locked to a common reference for SPEED, often a Black Burst Sync pulse generator.

When you'll press "PLAY " on the keyboard of your MicroLynx :
1/ the Tascam will start playing at nominal speed, and its Capstan Speed will be controlled continuously by the REF speed,
2/ TC from the Tascam tape track will be read by the MicroLync and it will give the Address where the DAW must go. Also a fresh TC from the Lynx TC generator ( in Jam Sync mode) will be sent to the DAW, and the WC from the AGC card will phase lock your DAW to the REF.

Then both your Tascam and your DAW will play in a perfectly stable and reliable way...every time !

Many moons ago TimeLine had published a booklet titled " SMPTE made simple " .
I heavily suggest you to find a copy, it explains a lot on synchronisation systems.

Good luck !

Best,
Guy

Yes, thanks to both you and @aurt and others for the very helpful information. I will try to get a copy of that book, because this subject is a little confusing.

 

[aurt]

SMPTE was the standard tool for most recording studios - MTC (MIDI Time Code) was a secondary choice but had its problems and you couldn’t put it directly on tape. There was a small lag in the SMPTE to MTC conversion in some synchronisers and also present in the MIDI transmission/reception circuitry - small but there. Also you couldn’t run really long distance with MIDI or you’d get dropouts.

Apologies, I meant drop frame. Not much use anywhere but the US, though checking, NTSC was a little more broadly used than I thought. Drop vs non drop has never given me a problem. So long as everyone is reading from the same hymnal.

A surprising number of workstations only use midi internally, and do the gearboxing in hardware purpose made for that. See: Pro Tools Sync-I/O. The connection to the computer is an old Mac serial cable carrying MTC for positional data. The DAW proper doesn’t see SMPTE, though it will display it as the timeline. So, I guess MTC can be ok if it’s a closed system with the bugs worked out. But yeah, I wouldn’t trust it for a six hour live video shoot using assorted brands of gear.

I’m pretty sure midi is an unbalanced signal, so I don’t doubt it has range issues. I don’t think I’ve ever tried to run it more than ten feet. Real time code runs fine over either balanced xlr or terminated bnc, depending on your industry, so it has a leg up for being robust.

 

[EmilFrid]

Is this the stuff I should get?

 

[aurt]

Does anyone recall specialized 1" machines referred to as a "layback" deck? They were used to "lay back" an audio track onto 1" C-format video tape. Special record head that could allow a "sweetened" audio mix to be recorded onto the small sized space on the edge of the video tape. The decks ran at an odd speed (8.something IPS as I recall).

In early 1990's, before our company went Full Blown Avid for in-house video post, we used an outside place for dealing with video projects. They had a MCI layback 1" machine. Our facility and theirs had 1/4" center stripe machines for moving audio elements back and forth. Of course, SMPTE everywhere <g>. We had a Microlynx in our studio that did a great job with our MTR-90 24 track, Sony 3/4", ProTools, the aforementioned Otari MX-55 center stripe machine and some other "partridges in pear trees".

At one point, we also had DAT machines and a Fostex ADAT machine with timecode facilities to handle various formats when dealing with outside audio facilities.

Bri

The Sony timecode DATs were serious kit. You had to love even the labeling on the circuit boards. Functional areas outlined and labeled. You could get halfway to fixed before cracking the book. Oh for the days. They chased surprisingly well even without the help of a sync box.

 

[Brian Roth]

The Sony timecode DATs were serious kit. You had to love even the labeling on the circuit boards. Functional areas outlined and labeled. You could get halfway to fixed before cracking the book. Oh for the days. They chased surprisingly well even without the help of a sync box.

We had two(?) Otari time code DATS back then. We had become an "Otari shop" with our analog reel-reel machines as well as an Otari Concept desk. So, we chose Otari for the DATs. That was NOT the best product Otari ever built as we learned after a couple of years. And they were EXPENSIVE...$10k+.

Oddly enough the Fostex time code ADAT machine we had was a decent machine. IIRC It was essentially an Alesis transport with Fostex audio and TC electronics.

Bri

 

[aurt]

Is this the stuff I should get?

That looks like an NTSC sync generator. Where you are, you might consider using a PAL box and sticking with 25 frame code. Drop frame is just one more thing to worry about. I don’t think I’ve ever worked with PAL burst and code, but I assume best practices translate. It shouldn’t be hard to find a suitable generator. Tektronix used to make the SPG300, which looks like it will do either, as well as generate 48k wordclock. The manual doesn’t specifically say that it’s frame locked, but there’s no reason to have it if it’s not. Probably find one on eBay.

 

[aurt]

We had two(?) Otari time code DATS back then. We had become an "Otari shop" with our analog reel-reel machines as well as an Otari Concept desk. So, we chose Otari for the DATs. That was NOT the best product Otari ever built as we learned after a couple of years. And they were EXPENSIVE...$10k+.

Oddly enough the Fostex time code ADAT machine we had was a decent machine. IIRC It was essentially an Alesis transport with Fostex audio and TC electronics.

Bri

I worked with some of those Concept desks, one of the flagship units and a couple of the one step down. I don’t remember which was the 1 and which was the Elite. The flagship had the dynamics in 8 channel blocks that plugged in on the back of things, yes? Those had a tendency to go toes up inconveniently, iirc. As we had it post-support, it wound up having fewer and fewer buckets with dynamics. Nice enough sounding desk, though.

 

[RoadrunnerOZ]

I’m pretty sure midi is an unbalanced signal, so I don’t doubt it has range issues. I don’t think I’ve ever tried to run it more than ten feet. Real time code runs fine over either balanced xlr or terminated bnc, depending on your industry, so it has a leg up for being robust.

MIDI has a data signal that operates an optocoupler at the receiving end and this signal is prone to interference and losses enough to corrupt the signal with long lead - the maximum is supposed to be 50 feet but I’ve seen MIDI playing up with much shorter leads. It’s just a 5V signal unbalanced.

 

[RoadrunnerOZ]

Is this the stuff I should get?

Why should you need anything if SMPTE sync is working for you already? If wanting to slave the Teac you need a synchroniser that has Tascam/Teac transport and motor servo control functionality.

 

[Brian Roth]

I worked with some of those Concept desks, one of the flagship units and a couple of the one step down. I don’t remember which was the 1 and which was the Elite. The flagship had the dynamics in 8 channel blocks that plugged in on the back of things, yes? Those had a tendency to go toes up inconveniently, iirc. As we had it post-support, it wound up having fewer and fewer buckets with dynamics. Nice enough sounding desk, though.

Ours was a very early model, so no dynamics....just fader automation. By that time, we had a ton of outboard dynamic gizmos. At the top left of the sidecar were six additional Audio+Design Compex modules....just the lower edge of the modules are visible.

Bri

 

[RoadrunnerOZ]

Is this the stuff I should get?

that's not a synchroniser, but a generator

 

[EmilFrid]

Why should you need anything if SMPTE sync is working for you already? If wanting to slave the Teac you need a synchroniser that has Tascam/Teac transport and motor servo control functionality.

Just thought it would be fun to try out different techniques. I'm usually too curious for my own good.

 

[JohnRoberts]

I vaguely recall experimenting back in the 80s with sending midi through longer than 50' XLR snakes. IIRC it worked.

JR

 

[abbey road d enfer]

Wouldn’t expect SMPTE to be the choice anywhere but the US.

The official name in Europe was EBU (European Broadcasting Union), but it was usually refered to as SMPTE/EBU, or simply "time code".

 

[aurt]

The official name in Europe was EBU (European Broadcasting Union), but it was usually refered to as SMPTE/EBU, or simply "time code".

As I mentioned in another response, I meant drop frame rather than SMPTE. And even then, I was a bit narrow. Should have said outside NTSC countries. Had a brainfart.

 

[abbey road d enfer]

I’m pretty sure midi is an unbalanced signal, so I don’t doubt it has range issues.

Official MIDI MIDI implementation is balanced, with 220 ohms in each leg. The receiver is floating.
The signal is single-ended, though.
The recommended limit is 50ft, but poor quality cables and connections can seriously reduce it.
However, I've used a modified version of the MIDI protocol on much larger distances (several 100 meters). This version included handshake that would slow down communication but provide error correction.
In an application that could tolerate the induced latency.

 

[Tubetec]

RTP midi provides realtime midi over ethernet cable , theres software you run on the pc end that replicates the port , Mac has the abillity built in .

 

[guy_4]

Is this the stuff I should

Yes

 

[guy_4]

That looks like an NTSC sync generator. Where you are, you might consider using a PAL box and sticking with 25 frame code. Drop frame is just one more thing to worry about. I don’t think I’ve ever worked with PAL burst and code, but I assume best practices translate. It shouldn’t be hard to find a suitable generator. Tektronix used to make the SPG300, which looks like it will do either, as well as generate 48k wordclock. The manual doesn’t specifically say that it’s frame locked, but there’s no reason to have it if it’s not. Probably find one on eBay.

In Europe you need a PAL Video Sync generator.
There was a cheap JVC unit that was popular in Europe in the past.