Sel-Sync.....

[Bruce Swedien]

Sel-Sync was an Ampex technique that I fell in love with immediately! It came along in 1955. If you look closely at that photo of me in front of my Ampex 300-3 you will see the Sel-Sync panel just below the bottom Ampex Record/Play electronics panel.

 

Here's a little explanation....

 

Sel-Sync or Selective Synchronous recording is the process of selectively using some record heads as play back heads so that new signals can be recorded on other tracks in perfect sync with the existing tracks. Sel-sync recording dramatically changed the recording process allowing overdubbing of individual recorded tracks.

 

Sel-sync along with the multi-track head was invented by Ross Snyder at Ampex in 1955.

 

Three problems had to be solved:

 

#1-mechanical alignment,

 

#2-switching of the record track to playback mode

 

#3-And a multitrack erase head.

 

The real problem though was the switching of a track between record and playback mode. Prior to sel-sync record heads were directly wired to the record electronics and playback heads were directly wired to the playback electronics. Also the designs of the two heads were very different. The problem of switching very low-level/high-impedance circuitry without introducing hum or noise had to be solved. Mort Fujii in the Ampex special projects lab was responsible for the actual design[1].

 

Ampex did not patent sel-sync because Ross Snyder did not think it would be of interest to more than a few musicians and an Ampex lawyer said the idea was obvious. Ampex only trademarked the name

 

Ross synder should have talked to Les Paul.

[russrags]

 

Bruce, great topic. Upon cutting my teeth, smack dab in the middle of Analog and Digital, of course SMPTE was my first introduction to syncing two machines, or sometimes 4-machines in your case !!!!!

 

The first time I encountered sel-sync or pilot tone what I called it, was when I got a chance to mix Muddy Waters for video of previously unreleased tapes of him LIVE in concert in 1971. It was a real challenge at first to get everything to sync up, as I was dealing with pilot tone, not SMPTE.

 

I managed to talk to a couple engineers in Nashville who had been around the block a time or two, and gave me an explanation I could understand what I was dealing with.

 

Since obtaining a machine was a real trick, what I ended up doing was printing my 2-track mixes to a Nagra 1/4" analog reel to reel, which also had "pilot tone" locked right up to picture, and the project won a pretty nice award too.

 

I'll go find a few You Tubes and post them here.

 

Russ

Nashville

[russrags]

OK here's yours truly hard at work with Sel Sync for the first time.

Man I've gotten a few hit's on You Tube yikes, I actually own a big chunk of this and the tapes are in my vault:

 

[YOUTUBE]w5IOou6qN1o[/YOUTUBE]

 

 

 

Bruce, is that your tone generator in the photo also?? I remember us using one on "Bad," and that's something I've done a few times later on, in fact I think I blew the doors off a couple clients cars with that method, 32 Hz as I recall from my notes.

 

Thanks Blue .. I just had an extra letter in it.

 

Russ

Nashville

[blue2blue]

Here's that YT vid, Russ. The YT embedding is the same as it's been since its introduction here. You only use the video's ID code, in this case, w5IOou6qN1o

 

w5IOou6qN1o

 

You first-timers.

 

 

So... you did the location sound for this?

 

Maybe you ought to consider taking adverts on that page. I'm not sure what all it can generate but long about 20K or 30K views, I think they start asking you if you want to go with ads; and you're way past that. (Oh, wait, I see that thing that looks like a vid in the upper right is actually some kind of DoubleClick ad. Never mind.)

[russrags]

No I didn't do the on location sound, it was recorded LIVE in 1971 and I was 13 yrs old ... it was recorded on 1" 8-track in a mobile truck, and shot on film with 4 camera's. I did A-D transfers and had the film developed, then put it all together in post. It was a huge effort. Got a W.C. Handy Award for "Best Traditional Blues Album of the Year in 2000. The CD was released world wide in many countries with different covers.

 

I'd known Muddy's manager for years and knew these tapes were available, it just took a while to find a home for them.

 

Bruce what was the name of the Muddy Waters record you made, I'd like to check it out .. Doug Stone too .. man he played a little small club here a few weeks ago.

 

Russ

Nashville

[blue2blue]

Good job! But I guess the WC Handy award probably counts for just a smidge more than my praise.

[MikeRivers]

The concept of Sel-Sync is pretty simple. By the time the Ampex MM series came around, they were using the same heads for record and reproduce so matching the head to the repro preamp was simple.

 

What really made it work, though, and this came along a little later, was automatic monitor switching for punch-ins. On the original Ampex Sel-Sync machines, you needed to do two things when punching in - switching the record head back to the record electronics, and switching the track output from the playback electronics to the record electronics so the player could hear himself. The reason why there was a "tape op" was because, given that the engineer might need a finger on a level control, a punch-in took three hands.

 

The later "sync panel" (integrated with the electronics design by the time the MM-1100 came around) used relays to do the head and monitor switching when you pressed the Record button. Sometimes they stuck or got dirty, but the principle worked great. This is one thing that didn't get carried over into the world of the DAW.

 

The Alesis ADAT had the idea right, but rather than using a mechanical relay in the analog signal path (the simplest way to do it), they did the switching on the digital side. The other digital multitracks from TASCAM, Mackie, RADAR, and the other little guys followed that model. It could be done in software rather than using a mechanical relay which both saved money and improved reliability, but at a cost. The monitor path included the A/D converter, the logic to turn the signal around, and the D/A converter. The time to turn around the data stream is pretty much negligible, but a round trip through the converters adds a delay in the 2-3 ms range to the monitor signal. That's not enough to make you play off time but when that delayed signal combines at a singer's eardrum with his own voice through the acoustic path through his throat, it's just the right amount of delay to produce a comb filter with several notches in the vocal range.

 

The depth of the notches is a function of the relative amplitudes of the two mixed signals and most of the time a singer will want his voice in the phones enough louder than what he hears of himself without phones so that the notches aren't very deep. But when you have a singer who doesn't want a lot of volume in the headphones, his voice will sound odd to him (but not to anybody else, and not on playback).

 

There are times when I really miss my MM-1100.

[russrags]

WOWSA !!!! We got a thread going on now boys

 

Good job! But I guess the WC Handy award probably counts for just a smidge more than my praise.

 

Blue I know your not a man of few words, so feel free to preach on Brother.

Mike ... Incredible .. thanks.

 

OK Bruce .. you set it up so it's your turn my friend,

 

Russ

Nashville

[Richard King]

The 4 track version of Bruce's machine. That piece of "pressed board" to the right in the picture is an EMT plate reverb which should have been in its own room.

[Richard King]

 

No I didn't do the on location sound, it was recorded LIVE in 1971 and I was 13 yrs old ... it was recorded on 1" 8-track in a mobile truck, and shot on film with 4 camera's. I did A-D transfers and had the film developed, then put it all together in post. It was a huge effort. Got a W.C. Handy Award for "Best Traditional Blues Album of the Year in 2000. The CD was released world wide in many countries with different covers. Russ Nashville

 

 

A great effort nicely done. It appears that he was using two mics for vocals, an EV RE-20 and some kind of an EV omni dynamic. I assume the omni was probably for the recording process. Interesting that the omni is sticking out so much that you wouldn't get much proximity effect on the RE-20, but then the RE-20 doesn't have much, if any, proximity effect, so I guess it matters more for gain than proximity.

[MikeRivers]

A great effort nicely done. It appears that he was using two mics for vocals, an EV RE-20 and some kind of an EV omni dynamic. I assume the omni was probably for the recording process. Interesting that the omni is sticking out so much that you wouldn't get much proximity effect on the RE-20, but then the RE-20 doesn't have much, if any, proximity effect, so I guess it matters more for gain than proximity.

A proper omni mic doesn't have any proximity effect because it responds purely to changes in air pressure, which are all around. Think of a barometer. The reading doesn't change when you turn it.

 

The RE-20 is one of EV's "Variable D" designs (I think D stands for "differential") that has a clever arrangement of the internal plumbing - the path that brings sound from the front of the mic around to the rear side of the diaphragm, which reduces proximity effect to nearly nothing by assuring that whatever gets to the back is close to 180 degrees out of phase with what's in the front at any frequency. It's a good trick.

 

The RE-15 is also a Variable-D mic which can instantly become an omni if you grab it by the shaft which has the vent holes in it. This is why those mics, which are pretty good at feedback rejection, suddenly feeds back when a singer, in a fit of emotion, grabs the mic by the part that vents to the rear of the diaphragm. I keep telling 'em that they should find a chick backup singer to grab instead.

[russrags]

I think the two mic's are just because nobody had a splitter box, one mic was for FOH the other for the recording. I've seen that done a lot back in the day. The recording was only one mic.

 

For the techies out there, the audio was recorded on 1" 8-track, I found a 3M 1" 8-track in great condition, did A-D transfers to a Tascam DA-88 in California, mixed it in Nashville on a Mackie 1604 with NO F/X's. A proven award winning combination. Mixdown Machine was Analog Nagra field recorder 15 ips.

Ooooh and for monitors, I just ripped the speakers out of my truck ... this was a while ago.

 

Get out of bed Bruce, we're talkin' 'boutcha Tell us some cool stories from way back when there wasn't all this technology available, how'd you push the boundries????

 

Russ

Nashville

[Richard King]

The RE-20 is one of EV's "Variable D" designs (I think D stands for "differential") that has a clever arrangement of the internal plumbing - the path that brings sound from the front of the mic around to the rear side of the diaphragm, which reduces proximity effect to nearly nothing by assuring that whatever gets to the back is close to 180 degrees out of phase with what's in the front at any frequency. It's a good trick. The RE-15 is also a Variable-D mic which can instantly become an omni if you grab it by the shaft which has the vent holes in it. This is why those mics, which are pretty good at feedback rejection, suddenly feeds back when a singer, in a fit of emotion, grabs the mic by the part that vents to the rear of the diaphragm. I keep telling 'em that they should find a chick backup singer to grab instead.

 

The rear vents in all the Variable D mics are what does the anti proximity thing, and, grabbing any of them will cause feedback problems because the rear vents also establish the cardioid pattern. Of course, I have seen the same happen with cardioids from other brands when they are cupped from behind the "ball" of the mic. Last night a harmonica player did this with an SM-58 and quickly had to turn down his "personal monitor" (one of those small stand mounted dealies). The interesting thing about the Variable D mics is that, in theory, cupping a variable d mic as he did last night with the SM-58 might not result is as much of a change since many of the rear vents would still be there (maybe).

[Bruce Swedien]

A proper omni mic doesn't have any proximity effect because it responds purely to changes in air pressure, which are all around. Think of a barometer. The reading doesn't change when you turn it. The RE-20 is one of EV's "Variable D" designs (I think D stands for "differential") that has a clever arrangement of the internal plumbing - the path that brings sound from the front of the mic around to the rear side of the diaphragm, which reduces proximity effect to nearly nothing by assuring that whatever gets to the back is close to 180 degrees out of phase with what's in the front at any frequency. It's a good trick. The RE-15 is also a Variable-D mic which can instantly become an omni if you grab it by the shaft which has the vent holes in it. This is why those mics, which are pretty good at feedback rejection, suddenly feeds back when a singer, in a fit of emotion, grabs the mic by the part that vents to the rear of the diaphragm. I keep telling 'em that they should find a chick backup singer to grab instead.

 

OK everybody.... read what Mike has to say about omni mikes. It's the truth!!!

 

Bruce Swedien

[Bruce Swedien]

Bruce, great topic. Upon cutting my teeth, smack dab in the middle of Analog and Digital, of course SMPTE was my first introduction to syncing two machines, or sometimes 4-machines in your case !!!!! The first time I encountered sel-sync or pilot tone what I called it, was when I got a chance to mix Muddy Waters for video of previously unreleased tapes of him LIVE in concert in 1971. It was a real challenge at first to get everything to sync up, as I was dealing with pilot tone, not SMPTE. I managed to talk to a couple engineers in Nashville who had been around the block a time or two, and gave me an explanation I could understand what I was dealing with. Since obtaining a machine was a real trick, what I ended up doing was printing my 2-track mixes to a Nagra 1/4" analog reel to reel, which also had "pilot tone" locked right up to picture, and the project won a pretty nice award too. I'll go find a few You Tubes and post them here. Russ Nashville

 

From Bruce.....

 

Pilottone and the related neo-pilottone are special synchronization signals recorded by analog audio recorders designed for use in motion picture production.

 

Before the adoption of timecode by the motion picture industry in the late 1980s, pilottone-sync was the basis of all professional magnetic motion picture sound recording systems, whereas most amateur film formats used pre-striped magnetic coating on the film itself for live-sound recording....

[MikeRivers]

 

OK everybody.... read what Mike has to say about omni mikes. It's the truth!!!

 

I failed to mention, as Richard pointed out, that the rear porting is there to establish the non-omni pattern, which also results in the proximity effect. The Variable-D system minimizes the proximity effect while maintaining a pretty good cardioid pattern.

 

Dunno how this got into the Sel-Sync discussion when we have a perfectly good Proximity Effect discussion going on elsewhere. Maybe we need a wizard to do some shape-shifting.

[John Sayers]

What really made it work, though, and this came along a little later, was automatic monitor switching for punch-ins. On the original Ampex Sel-Sync machines, you needed to do two things when punching in - switching the record head back to the record electronics, and switching the track output from the playback electronics to the record electronics so the player could hear himself. The reason why there was a "tape op" was because, given that the engineer might need a finger on a level control, a punch-in took three hands. There are times when I really miss my MM-1100.

 

Yup - you had to be fast to make all the switches and still capture the audio drop in We originally had a Scully 8 track.

 

 

We had all these machines - the 8 track was built on a converted video deck and we upped it to a 16 track later on.

[Richard King]

Thankfully, I didn't install the 16 track Scully shown in this picture, but, I did assist in the installation of the Tangent 3216 console that was used to feed it.

[MikeRivers]

 

We had all these machines - the 8 track was built on a converted video deck and we upped it to a 16 track later on.

 

Where and when was that? George Schowerer has some pictures of the 16-track recorder that he and his crew at Mirasound built up in, I think, 1966. It was essentially an MM-1000 before Ampex started making it. They used a VR-1000 transport, AG-440 electronics, and designed their own switching system. Ampex made heads for them, then decided that it was a pretty good idea and came up with the MM-1000 in 1968. Mirasound's was the second 16-track in the US, he claimed. I don't remember if it was Motown or Capitol who built one first.

 

Those were the days when, if you needed something in the studio, no matter how complex, if you couldn't buy it, you built it. Nearly all consoles were assembled on site back then.

[John Sayers]

Mike - our MM1000 8/16 track had an Ampex logo as did our 2 and 4 track machines. This was in 1968. Remember that Ampex already had a series of 2" Video recorders in action.

 

I agree about the home built machines. My first studio had a hand made 4 track in the main room and a bank of home built 17.5mm dubbers in the room behind.

 

This was our master mono machine.

 

 

I later moved to Armstrongs studios which had a Scully 8 track and a locally built Optronics console..

 

 

 

That was replaced with a locally built Optronics 16 track.

[Bruce Swedien]

Wow..... Does that photo of the Ampex 350 mono machine bring back memories!!!

 

Bruce Swedien

[John Sayers]

Yeah Bruce - I learnt how to edit tape with razor blade and scissors on that machine

[Bruce Swedien]

John.... Yeah me too...

 

Bruce

[Cry Logic]

This thread is fascinating.

 

All that pre digital analog gear looks so archaic now.

 

Like an old Model T Ford.

 

Just unbelievable how fast it has all evolved.

 

From razor blades to loops in less than 50 years!