Dolby B Component for Foobar2000

H

helpfuldad

Audiophyte
I'm probably going to buy an analog Dolby B unit for playing back a number of stereo sources. There are a surprising number of really great digital titles that the engineer reproduced and neglected to apply Dolby B on playback that are begging for it. For example, the UHQCD release of "This is the Moody Blues" in MQA decodes to 352.8 with great detail, but it has that telltale high end that I remember from playing my cassettes in my car.

The title that is prompting me to write this is Bridge Over Troubled Water in Quad, Roy Hallee Mix. Wow, what a great album. But. I'd need two analog dolby units for this, so I thought maybe Foobar2000 has a component for this but, no such luck. In the digital domain, I think this might be challenging because it's a smooth curve that would need to increase amplitude as frequency increases. While I know a lot about signal processing and programming, I'm not quite sure how I'd write such code to do this smoothly. To say nothing of the calibration routine that would accompany it.

Does anyone have a solution for true, accurate, playback Dolby B for multchannel, PCM sources?
 
TLS Guy

TLS Guy

Seriously, I have no life.
I'm probably going to buy an analog Dolby B unit for playing back a number of stereo sources. There are a surprising number of really great digital titles that the engineer reproduced and neglected to apply Dolby B on playback that are begging for it. For example, the UHQCD release of "This is the Moody Blues" in MQA decodes to 352.8 with great detail, but it has that telltale high end that I remember from playing my cassettes in my car.

The title that is prompting me to write this is Bridge Over Troubled Water in Quad, Roy Hallee Mix. Wow, what a great album. But. I'd need two analog dolby units for this, so I thought maybe Foobar2000 has a component for this but, no such luck. In the digital domain, I think this might be challenging because it's a smooth curve that would need to increase amplitude as frequency increases. While I know a lot about signal processing and programming, I'm not quite sure how I'd write such code to do this smoothly. To say nothing of the calibration routine that would accompany it.

Does anyone have a solution for true, accurate, playback Dolby B for multchannel, PCM sources?
Well decoding Dolby B is an analog process. So you would have to decode PCM to analog. The only stand alone Dolby B decoder I know of was the Advent Dolby B decoder. There could be others I don't know about. You can see mine in the photo below. It is in the far right of the top shelf.



Now one thing you have to understand about Dolby decoding, it is level dependent, so absent the calibration tones you would have to experiment and take a guess at it.

I bought my decoder a number of years ago and restored it. A dealer had it in non working condition. They are a really rare item.

The other option is a reel to reel Dolby recorder. The tape machine below that Advent Unit is a Revox A77 MK IV. They made quite a few of these with a Dolby decoder. That machine is non Dolby. So you could record to a Dolby B machine without decode, and then play back with decode.

You would not need two decoders if you have a DAW, as I do, with professional software.

You could record the tracks separately and then synchronize them. That is not difficult with pro software.

By the way next to the Advent decoder, there is a dbx II decoder for both tape and LP. Another rare item. There is a lot of rare gear in that picture, which is part of the working museum end of my system. That TEAC master cassette unit is another very rare item.
 
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highfigh

highfigh

Audioholic Slumlord
Well decoding Dolby B is an analog process. So you would have to decode PCM to analog. The only stand alone Dolby B decoder I know of was the Advent Dolby B decoder. There could be others I don't know about. You can see mine in the photo below. It is in the far right of the top shelf.



Now one thing you have to understand about Dolby decoding, it is level dependent, so absent the calibration tones you would have to experiment and take a guess at it.

I bought my decoder a number of years ago and restored it. A dealer had it in non working condition. They are a really rare item.

The other option is a reel to reel Dolby recorder. The tape machine below that Advent Unit is a Revox MK IV. They made quite a few of these with a Dolby decoder. That machine is non Dolby. So you could record to a Dolby B machine without decode, and then play back with decode.

You would not need two decoders if you have a DAW, as I do, with professional software.

You could record the tracks separately and then synchronize them. That is not difficult with pro software.

By the way next to the Advent decoder, there is a dbx II decoder for both tape and LP. Another rare item. There is a lot of rare gear in that picture, which is part of the working museum end of my system. That TEAC master cassette unit is another very rare item.
What, no wire recorder? :)
 
H

helpfuldad

Audiophyte
Well decoding Dolby B is an analog process. So you would have to decode PCM to analog. The only stand alone Dolby B decoder I know of was the Advent Dolby B decoder. There could be others I don't know about. You can see mine in the photo below. It is in the far right of the top shelf.



Now one thing you have to understand about Dolby decoding, it is level dependent, so absent the calibration tones you would have to experiment and take a guess at it.

I bought my decoder a number of years ago and restored it. A dealer had it in non working condition. They are a really rare item.

The other option is a reel to reel Dolby recorder. The tape machine below that Advent Unit is a Revox MK IV. They made quite a few of these with a Dolby decoder. That machine is non Dolby. So you could record to a Dolby B machine without decode, and then play back with decode.

You would not need two decoders if you have a DAW, as I do, with professional software.

You could record the tracks separately and then synchronize them. That is not difficult with pro software.

By the way next to the Advent decoder, there is a dbx II decoder for both tape and LP. Another rare item. There is a lot of rare gear in that picture, which is part of the working museum end of my system. That TEAC master cassette unit is another very rare item.
Like I said, I’m probably going to buy a Dolby B unit for my stereo sources but would need two for quad. Also, like I said, it’s probably a difficult coding for a foobar2000 component because its a smooth level/freq, but it would be nice to have for all of these digital titles I have.

Hoping that some signal processing programmer has thought about this and may be working on it. I really don’t know how to program it other than a table lookup as I don’t believe there’s a Dolby B transfer function, leaving it to table lookups.

as for dbx, it has no application in this situation with titles recorded with Dolby B
 
TLS Guy

TLS Guy

Seriously, I have no life.
Like I said, I’m probably going to buy a Dolby B unit for my stereo sources but would need two for quad. Also, like I said, it’s probably a difficult coding for a foobar2000 component because its a smooth level/freq, but it would be nice to have for all of these digital titles I have.

Hoping that some signal processing programmer has thought about this and may be working on it. I really don’t know how to program it other than a table lookup as I don’t believe there’s a Dolby B transfer function, leaving it to table lookups.

as for dbx, it has no application in this situation with titles recorded with Dolby B
I can not find that anyone makes a Dolby B stand alone decoder. The chance of finding a vintage one is remote. I just stumbled into mine a jumped at the chance.

Your question has been asked before. You might find this discussion on the Steinberg forums of interest. I have Steinberg software (WaveLab Pro) loaded on my DAW.
 
TLS Guy

TLS Guy

Seriously, I have no life.
I'm probably going to buy an analog Dolby B unit for playing back a number of stereo sources. There are a surprising number of really great digital titles that the engineer reproduced and neglected to apply Dolby B on playback that are begging for it. For example, the UHQCD release of "This is the Moody Blues" in MQA decodes to 352.8 with great detail, but it has that telltale high end that I remember from playing my cassettes in my car.

The title that is prompting me to write this is Bridge Over Troubled Water in Quad, Roy Hallee Mix. Wow, what a great album. But. I'd need two analog dolby units for this, so I thought maybe Foobar2000 has a component for this but, no such luck. In the digital domain, I think this might be challenging because it's a smooth curve that would need to increase amplitude as frequency increases. While I know a lot about signal processing and programming, I'm not quite sure how I'd write such code to do this smoothly. To say nothing of the calibration routine that would accompany it.

Does anyone have a solution for true, accurate, playback Dolby B for multchannel, PCM sources?
I have been thinking about this. My conclusion is that this is not lack of Dolby B decoding. The masters would have been Dolby A. Dolby A has three distinct bands of dynamic code/encode noise compression. This is extremely level critical. If the level calibrations from the masters are lost, then it is anybody's guess how to play the tape back. So you usually end up with the problem you describe.

That UHQCD looks to me like a really bogus piece of audiophoolery and makes no sense to me at all.

As for Bridge Over Troubled Waters Quadraphonic issue, that is an old SQ coded recording from that disastrous quadraphonic analog era. Nothing good was achieved by that.

So my conclusion is that you are wasting your time, and the best you can do is use an equalizer and set it by ear.
 
lovinthehd

lovinthehd

Audioholic Jedi
Who was the member who was digging into Dolby applied one end and not another in some recordings due the shift in tech? Thought it was more Dolby A oriented but can't remember his handle and my meager search turned up nothing I was thinking of. Canadian guy IIRC.....
 
TLS Guy

TLS Guy

Seriously, I have no life.
Who was the member who was digging into Dolby applied one end and not another in some recordings due the shift in tech? Thought it was more Dolby A oriented but can't remember his handle and my meager search turned up nothing I was thinking of. Canadian guy IIRC.....
I don't recall that, but may be I missed it. Anyhow, my point is that any digital transfer from an analog master tape, will not have a Dolby B problem, as no one mastered with Dolby B, but Dolby A was the most common codec used by mastering engineers. Some used dbx 1, but any dbx 1 not played back with the codec would not be listenable. However dbx is not level dependent , like the Dolby codec, so you don't need levelling tones, you can just play back through the dbx 1 decoder. Although as I used to master in dbx 1, that is not quite true, but it is tolerant of significant level mismatches between record and playback, and any problems are easily corrected by ear.

The problem with dbx is that you have to keep your machines in very good order, with the flattest frequency response you can manage, as any frequency response errors between record and playback are doubled.

The other analog codec was the Telefunken, but I personally have had no experience with that.
 
H

helpfuldad

Audiophyte
I can not find that anyone makes a Dolby B stand alone decoder. The chance of finding a vintage one is remote. I just stumbled into mine a jumped at the chance.

Your question has been asked before. You might find this discussion on the Steinberg forums of interest. I have Steinberg software (WaveLab Pro) loaded on my DAW.
For those who’d like to get one, these are relatively plentiful on ebay(considering demand), but I can’t remember the models. Teac has 3-4 models, advent as well

 
H

helpfuldad

Audiophyte
I have been thinking about this. My conclusion is that this is not lack of Dolby B decoding. The masters would have been Dolby A. Dolby A has three distinct bands of dynamic code/encode noise compression. This is extremely level critical. If the level calibrations from the masters are lost, then it is anybody's guess how to play the tape back. So you usually end up with the problem you describe.

That UHQCD looks to me like a really bogus piece of audiophoolery and makes no sense to me at all.

As for Bridge Over Troubled Waters Quadraphonic issue, that is an old SQ coded recording from that disastrous quadraphonic analog era. Nothing good was achieved by that.

So my conclusion is that you are wasting your time, and the best you can do is use an equalizer and set it by ear.
The Moody Blues Quad Catalog were all offered for sale in Quad with Dolby B, as were America Quad titles. So (a) production master(s) exist(ed) at some time
 
TLS Guy

TLS Guy

Seriously, I have no life.
The Moody Blues Quad Catalog were all offered for sale in Quad with Dolby B, as were America Quad titles. So (a) production master(s) exist(ed) at some time
The masters will all be either Dolby A or dbx1. No one ever mastered in Dolby B. The process was this, the master was dubbed and decoded, and then copied to the production high speed master, and this is where the Dolby B code was added. However, no one copied in real time. So this was the high speed duplication version. In high speed duplication there is always HF loss. This required a boost of HF to the duplication master. So if someone did make copies for sale from a duplication master, even if they used Dolby B decode, it would be HF heavy and not sound right. I can not imagine some idiot doing that, but anything is possible.

My best guess is that they used the Dolby A or dbx 1 master and did not get the levels correct if it was Dolby A, and there were frequency response errors between the master recorder and the recorder used for making the production dub if the master was dbx1.

As I think about this, it is very unlikely that the problem you are having is a Dolby B decode problem. It is almost certainly one of the issues I have raised.

I used to make professional recordings back in the day, mainly for radio broadcast, but I did have a high speed duplication system to make Dolby B tapes. So I know what the process is, and what great care you have to take to get it right. All machines must be in top condition, and you have to really listen to the high speed copies and remaster the duplication tape until you get the HF balance right. Most did not, and so there are a lot of less then optimal results around.

So I think this notion, widespread on the Net, that this is an issue due to not decoding Dolby B code is almost certainly NOT true, and much more complicated.

You have to understand what the process is, to understand what has likely gone wrong.

There is an Advent 100 A that has gone on eBay since last night.

One other caution, even if the tapes are Dolby B encoded, unless you have the level tones on the tapes, you will have a huge problem getting them to sound right. That is what those level meters on that Advent unit are all about. The Advent unit is the best stand alone Dolby unit, and is engineered correctly.

I have some commercial Dolby B reel to reel tapes and they are headed by the tones.

The only commercial real time tape duplicates that I know of where from Everest, and they are on reel to reel half track stereo 7.5 ips. I have a few of those also.
 
H

helpfuldad

Audiophyte
The masters will all be either Dolby A or dbx1. No one ever mastered in Dolby B. The process was this, the master was dubbed and decoded, and then copied to the production high speed master, and this is where the Dolby B code was added. However, no one copied in real time. So this was the high speed duplication version. In high speed duplication there is always HF loss. This required a boost of HF to the duplication master. So if someone did make copies for sale from a duplication master, even if they used Dolby B decode, it would be HF heavy and not sound right. I can not imagine some idiot doing that, but anything is possible.

My best guess is that they used the Dolby A or dbx 1 master and did not get the levels correct if it was Dolby A, and there were frequency response errors between the master recorder and the recorder used for making the production dub if the master was dbx1.

As I think about this, it is very unlikely that the problem you are having is a Dolby B decode problem. It is almost certainly one of the issues I have raised.

I used to make professional recordings back in the day, mainly for radio broadcast, but I did have a high speed duplication system to make Dolby B tapes. So I know what the process is, and what great care you have to take to get it right. All machines must be in top condition, and you have to really listen to the high speed copies and remaster the duplication tape until you get the HF balance right. Most did not, and so there are a lot of less then optimal results around.

So I think this notion, widespread on the Net, that this is an issue due to not decoding Dolby B code is almost certainly NOT true, and much more complicated.

You have to understand what the process is, to understand what has likely gone wrong.

There is an Advent 100 A that has gone on eBay since last night.

One other caution, even if the tapes are Dolby B encoded, unless you have the level tones on the tapes, you will have a huge problem getting them to sound right. That is what those level meters on that Advent unit are all about. The Advent unit is the best stand alone Dolby unit, and is engineered correctly.

I have some commercial Dolby B reel to reel tapes and they are headed by the tones.

The only commercial real time tape duplicates that I know of where from Everest, and they are on reel to reel half track stereo 7.5 ips. I have a few of those also.
Someone produced a production master to create the r2r tapes for sale as well as stereo cassettes so they either exist now or did exist. I didn’t post to be told I don’t need this.
 
TLS Guy

TLS Guy

Seriously, I have no life.
Someone produced a production master to create the r2r tapes for sale as well as stereo cassettes so they either exist now or did exist. I didn’t post to be told I don’t need this.
I dear say they do, but what is the provenance of those tapes and from what part of the production do they come from? That is basically the issue. Without that data, you have no idea what the underlying cause of an issue is, and even less how to correct it. So there will be the original master, then the dub for editing, and then the production masters, for LP, cassette, eight track and in some cases reel to reel. All will require production masters with different characteristics. Some will be in the original code, like the master and usually the edited master. That will be decoded in the LP mastering stage. So those tapes will be Dolby A mostly, and some dbx1. Then you have the production master for cassette and eight tracks, they will be customized for high speed duplication and will contain Dolby B encoding or not.

These codecs like Dolby and dbx, are not just frequency Eq, they are dynamic to avoid high frequency tape saturation. So the Eq applied varies with spl. on a moment by moment basis.

So to make a digital copy, you would hope to have the first dub edited master. You never edit a master, as you can not undo a mistake. So the first dub is as far as you can go back. The others would not be much use for a digital transfer, but it is just possible some cow boys might do it.

I am just trying to help you understand how things were done, in this now bygone era.

I can tell you the digital age, once we had computer editing and DAWs, made life a lot easier. Back in the "good old days" a lot of skill and experience was required.

This is not the simple straightforward issue you and make it out, and would like it to be. It is complex.
 
lovinthehd

lovinthehd

Audioholic Jedi
I don't recall that, but may be I missed it. Anyhow, my point is that any digital transfer from an analog master tape, will not have a Dolby B problem, as no one mastered with Dolby B, but Dolby A was the most common codec used by mastering engineers. Some used dbx 1, but any dbx 1 not played back with the codec would not be listenable. However dbx is not level dependent , like the Dolby codec, so you don't need levelling tones, you can just play back through the dbx 1 decoder. Although as I used to master in dbx 1, that is not quite true, but it is tolerant of significant level mismatches between record and playback, and any problems are easily corrected by ear.

The problem with dbx is that you have to keep your machines in very good order, with the flattest frequency response you can manage, as any frequency response errors between record and playback are doubled.

The other analog codec was the Telefunken, but I personally have had no experience with that.
I searched around for it but don't remember the poster's ID nor various search terms have uncovered it....I want to say he was from Canada and had a couple long posts on his efforts with various CDs that he claimed hadn't bothered with a Dolby decode,, believe his solution was software based. This was maybe two years ago or so?
 
TLS Guy

TLS Guy

Seriously, I have no life.
I searched around for it but don't remember the poster's ID nor various search terms have uncovered it....I want to say he was from Canada and had a couple long posts on his efforts with various CDs that he claimed hadn't bothered with a Dolby decode,, believe his solution was software based. This was maybe two years ago or so?
As I said, I don't recall that post. However, this issue is often attributed to the engineers not bothering to decode Dolby B. That is an understandable thought if you have no experience or knowledge of the production process. My point is, though this misconception is understandable, it is highly unlikely to be the correct reason.
 
lovinthehd

lovinthehd

Audioholic Jedi
As I said, I don't recall that post. However, this issue is often attributed to the engineers not bothering to decode Dolby B. That is an understandable thought if you have no experience or knowledge of the production process. My point is, though this misconception is understandable, it is highly unlikely to be the correct reason.
A little more searching and I found the guy (johndyson10) I was thinking of, here are his threads https://forums.audioholics.com/forums/search/631061/
 
lovinthehd

lovinthehd

Audioholic Jedi
For some reason that link does not work.
It had these three threads in the search I linked (which works for me)
 
TLS Guy

TLS Guy

Seriously, I have no life.
It had these three threads in the search I linked (which works for me)
Yes, I do remember that now you have found it. You are obviously less senile than I am by a margin.

But he makes my point that the problem is Dolby A decoding and not Dolby B. He is absolutely correct, and his software approach is interesting. I don't know if it is fully developed. As I said no one is going to take a Dolby B tape for a master.

I do have a pair of Dolby A decoders. Dolby only produced these as single channel and never two channel as far as I know. So for stereo you need two units,, they are all 10" rack units.
 
lovinthehd

lovinthehd

Audioholic Jedi
Hey, I'll put my senility up against anyone's these days :) My memory works strangely sometimes I'll remember something like that but not the food I stuck in the microwave to warm up....
 
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