Topic: Roland R-07 32-bit floating point!

[TheJez]

Summary: Could the Roland R-07 be a multi-ADC 32-bit fp recorder in disguise?

Sorry guys, I must admit: The title of this message is a bit of a click bait. At first I wanted to put a question mark at the end, but then I thought: “Anybody seeing that will think it’s a post from someone too lazy to read the spec sheet of the R-07 and won’t even bother to further read this post.” I am hoping to get interest from people knowing/owning the Roland R-07 and people interested in 32-bit fp recording…

Some background: Since a little while I am looking for a replacement of my Edirol R-09HR. When going through all this information on TS I concluded that 32bit-fp multi-adc is the way to go for my needs. So when someone on TS very kindly offered me a Roland R-07 for a very reasonable price, I still turned him down “because I want to go 32bit”… However, this offer made me think…

A couple of years ago I read about the R-07 and about its safety track, recorded at a lower volume, as a backup without distortion if the record level was set too high. That sounded like a very useful feature! On November 29, 2019, someone wrote on TS about this device: “I think the dual recording levels is far more useful than remote app for stealth conditions. I now go in with the levels pre-set and never look at the device, or the app, or worry about levels at all.” And also: “With the dual recording I just set it to 48 and then forget” Hmmm, sounds familiar? I’ve often seen very similar remarks while reading up on 32-bit multi-adc recording. Set-and-forget, how great would that be!

And now I started wondering about the signal path of this safety track on the R-07. So I went through all 39 pages on TS about the R-07 to see if there’s any info about it. All I found was someone claiming on December 19, 2018: “Metering and dual recording happen post-ADC.”. Would it really be true that dual recording is completely post-ADC? Personally, I find that hard to believe when looking at the possible sources of clipping distortion due to too high record level in this recorder. I guess there are two potential places where clipping could occur:
1)   At the analog input stage ((amplified) input signal too hot to handle by the analog components)
2)   In the ADC (signal coming into the ADC too hot, resulting in clipping samples)
(I can’t think of a probable, realistic cause of clipping post-adc in this device)

Now if the signal is clipping, either due to 1) or 2), then reducing the level post-ADC by e.g. -20dB and then storing that as a safety track will not solve the clipping! So it means there must be two ADC’s: One for the normal track, one for the safety track. And possibly, there will even be two analog stages! This would result in the following signal paths:

(see attached picture)

There would be two identical paths, with only a difference in the applied gain in the input stage. For the normal track, the gain 'x' as set by the user is applied. As we know, in 2xWAV mode, this is a value between 42-100. For the safety track, a gain of ‘x-42’ is applied. (If I’m correct, in the latest firmware, the offset of the safety track can be selected from -6/-12/-20db. I guess ‘-42’ would then match a -20db reduction…)
Now if these assumptions about the signal path would be correct, then we have a device very similar to the current 32-bit devices. The only thing missing is a piece of logic/signal processing that’s taking the samples coming out of the two 24-bit ADC’s and combining this into a 32-bit float sample. I know this part is the real ‘heart’ of 32-bit float multi-adc recorder, but… is this something that really has to be done in real-time within the device?? I’d say no, not necessarily… As long as you store the output of the two ADC’s, you could combine these into 32-bit float anytime you want!

This missing piece of logic could very well be implemented as a software program running on a PC. The required algorithm doesn’t seem extremely complex, imho…
So what do you think? Could this potentially work? Where did I go wrong in my thinking process? Hope to hear your thoughts…

[aaronji]

The 32-bit floating point recorders split the incoming signal into two (or more) gain-ranged streams which have different gains applied before conversion.

[TheJez]

The 32-bit floating point recorders split the incoming signal into two (or more) gain-ranged streams which have different gains applied before conversion.

Exactly! But isn’t the R-07 doing the exact same thing, but then to get the normal file and the safety file?

[aaronji]

No. The R07 doesn't split the signal into two parts. It sends the whole signal down both paths.

[TheJez]

No. The R07 doesn't split the signal into two parts. It sends the whole signal down both paths.

Then I think that, even after reading all the threads about 32 bit multi-adc recording, I still seem to miss some details about the technology behind it. Wouldn’t splitting the signal as you describe introduce all kinds of frequency components that are not part of the original signal? Isn’t the full signal fed into two adc’s (although at different levels) and isn’t then the output of the adc’s combined by taking e.g. a weighted average of the two samples, where the applied weight depends on the actual signal strength?
Hopefully you can elaborate a bit on the splitting mechanism you mentioned to help me understand…

[grawk]

The R07 doesn't have the 32 bit float gimmick, but the safety track is in the real world the same thing.  20db is a LOT of free headroom. And it doesn't have the theoretical problem people were complaining about last year, where there's noise at the transition point between the 2 adcs in the 32 bit recorders.

[adrianb]

The R-07 is my go to for all stealth recordings now, and I think it might be my quote about “set and forget” which is what I do and have never had a failed recording with this unit.

It’s small, made of plastic, so easy to get into any venue whatever the security. I have the safety track set at -12dB. I have had the main tracks clipping on a couple of occasions, but found the safety tracks to be good.

I don’t even use a battery box these days, just run my CA mics straight in. I’ve just checked the PIP voltage and it’s 3.1v.

I had high hopes for the Deity PR-2 as a set and forget unit, but since it isn’t 32-bit stereo as promised the R-07 seems to be the best solution out there for me.

[unidentified]

The R07 doesn't have the 32 bit float gimmick, but the safety track is in the real world the same thing.  20db is a LOT of free headroom. And it doesn't have the theoretical problem people were complaining about last year, where there's noise at the transition point between the 2 adcs in the 32 bit recorders.

Emphasis on theoretical.

[dallman]

The R07 doesn't have the 32 bit float gimmick, but the safety track is in the real world the same thing.  20db is a LOT of free headroom. And it doesn't have the theoretical problem people were complaining about last year, where there's noise at the transition point between the 2 adcs in the 32 bit recorders.

You might call it a gimmick, but for people who record shows where you get one shot at the recording, no re-do's, and often have no ability to set levels in advance, I'd call it an improvement or upgrade. You are entitled to your opinion though. It is not the same as a safety track at all, the safety track often has more self noise. I consider the Roland R05 and R07 2 excellent decks for recording, but they are not the same in any way as a 32Bit deck. I have not had any issues ever with transition noise on a 32Bit deck. I have been using the MixPre 6 II 32 Bit deck since 2019, no transition noise issues at all, and the 32Bit float market has grown from there. Necessary sometimes, and useful most of the time. It is in no way a step backwards or sideways. I still often record at 24Bit depending on the deck, venue and such, but I think slowly that will happen less and less as more new decks hit the market. I was happy to retire my 16 bit Nomad Jukebox II 15 or 20 years ago for my 24Bit Tascam HDP-2, also still a great deck and that in no way means I could not get great recordings with either of those decks. However 24Bit was an improvement and 24 Bit decks over time got smaller and easier to use. I started recording on a Concord cassette deck with an included pencil mic in 1971, so I have seen some change which I am always happy to embrace.

[roffels]

You might call it a gimmick, but for people who record shows where you get one shot at the recording, no re-do's, and often have no ability to set levels in advance, I'd call it an improvement or upgrade. You are entitled to your opinion though. It is not the same as a safety track at all, the safety track often has more self noise.

That's been my experience as well. The Roland r07's safety track was often very noisy, lots of hiss. It also couldn't handle line-level inputs without an attenuator. Give me a Zoom F3 with 32-bit any day.

[TheJez]

You might call it a gimmick, but for people who record shows where you get one shot at the recording, no re-do's, and often have no ability to set levels in advance, I'd call it an improvement or upgrade. You are entitled to your opinion though. It is not the same as a safety track at all, the safety track often has more self noise.

That's been my experience as well. The Roland r07's safety track was often very noisy, lots of hiss. It also couldn't handle line-level inputs without an attenuator. Give me a Zoom F3 with 32-bit any day.

Maybe I'm wrong, but it feels a bit easy to bash the safety track without giving any context. Was the record level set rather low in the first place? Yes, then obviously the safety track will be noisier. And indeed, if the input signal is too hot for the analog input part, then both normal and safety track will likely distord. And yes, the F3 analog input stage can handle a hotter signal. But that's not my point.

I guess R07-owners will set the record levels in such a way that the main track will likely not clip. And if it does after all, they can use the safety track instead. Or maybe they start mixing the main track and the safety track, so only the clipping parts will be replaced with the safety track parts. Anyway, this sounds like a tedious job, and will result in different noise floors for the main track and safety track parts.

In my proposal, it doesn't matter much if the main track clips. It is even encouraged to make it clip a bit to fully profit from the dual-ADC of the R07! Eventually, for these clipping main track samples, we can use the safety track samples. Maybe the attached picture will help understanding my intention.
The R07 has two 24 bits ADC's. Each has a theoretical dynamic range of 144dB. Let's assume the safety track ADC will process the signal attentuated by -20dB. Then 'my algorithm' will look like this:

• Read a 24 bit sample from the main track file and the safety track file
• Convert the samples from both files to 32bit floating point. This is done to extend the possible dynamic range and to prevent introducing errors further down the line while doing math on the samples
• Amplify the safety track sample by 20dB, so it becomes 'equal' to the main track sample.
• If the main track sample < -124dB, the output sample will be the main track sample (Area A)
• Else if the main track sample is between 0dB and -124dB (Area B), we'll calculate a weighted output sample. E.g. when main track sample is -124dB, the output sample is (100% of main track sample + 0% of the amplified safety track sample). When the main track sample is just below 0dB (so just not clipped), then the output sample is (0% of main track sample + 100% of the amplified safety track sample). But half way, at main track sample is -62dB, the output sample is (50% of main track sample + 50% of the amplified safety track sample), etc.
• Else (so the main track sample is clipped and the amplified safety track sample is >= 0dB (Area D)), use the amplified safety track sample as output

This way, the problem of manually combining main and safety tracks, and dealing with different noise floors for the two tracks is mitigated. And also we get plenty more headroom and don't have to worry too much about setting the record level right. Let it clip, I would say!
I guess there could be some optimizations, e.g. automatically calculating the true level difference between the two tracks (as it won't be exactly 20.0000000 dB), or changing the size of the area where the weighted value is calculated to more realistic boundaries instead of the theoretical boundaries. E.g. I can imagine that using the recorder noise floor as lower boundary of the 'Area B' would make more sense.

Is this still a stupid idea, or is it making sense? I guess the F3 and friends are using similar algorithms to combine the output of the ADC's, but they do it in real time instead of 'offline'...

[roffels]

You might call it a gimmick, but for people who record shows where you get one shot at the recording, no re-do's, and often have no ability to set levels in advance, I'd call it an improvement or upgrade. You are entitled to your opinion though. It is not the same as a safety track at all, the safety track often has more self noise.

That's been my experience as well. The Roland r07's safety track was often very noisy, lots of hiss. It also couldn't handle line-level inputs without an attenuator. Give me a Zoom F3 with 32-bit any day.

Maybe I'm wrong, but it feels a bit easy to bash the safety track without giving any context.

Likewise, I think it's easy to praise a hypothetical while ignoring real world experience. The main track clipped in situations that had high dynamic range, so I'd default to the safety track, which was full of hiss. It was a mess of a recording that needing a lot of post work to get listenable. Glad to have the safety track, but I'd rather skip all that.

[TheJez]

You might call it a gimmick, but for people who record shows where you get one shot at the recording, no re-do's, and often have no ability to set levels in advance, I'd call it an improvement or upgrade. You are entitled to your opinion though. It is not the same as a safety track at all, the safety track often has more self noise.

That's been my experience as well. The Roland r07's safety track was often very noisy, lots of hiss. It also couldn't handle line-level inputs without an attenuator. Give me a Zoom F3 with 32-bit any day.

Maybe I'm wrong, but it feels a bit easy to bash the safety track without giving any context.

Likewise, I think it's easy to praise a hypothetical while ignoring real world experience. The main track clipped in situations that had high dynamic range, so I'd default to the safety track, which was full of hiss. It was a mess of a recording that needing a lot of post work to get listenable. Glad to have the safety track, but I'd rather skip all that.

I didn't mean to disrespect anybody, and I'm sorry if I came across like that. High dynamic situations are a pain to deal with regarding setting the levels right. I have similar eperiences whith high dynamic shows (and no safety track feature on the recorder) where I was so scared to set the levels too high that I ended up with a recording with lots of noise in the quiet parts. I think in such a situation you could have had benefit from a little piece of software as described that could automatically merge the two tracks into one in a smart way, instead of manually merging or having to opt for the safety track that is noisy in the quiet parts.

[Rairun]

You might call it a gimmick, but for people who record shows where you get one shot at the recording, no re-do's, and often have no ability to set levels in advance, I'd call it an improvement or upgrade. You are entitled to your opinion though. It is not the same as a safety track at all, the safety track often has more self noise.

That's been my experience as well. The Roland r07's safety track was often very noisy, lots of hiss. It also couldn't handle line-level inputs without an attenuator. Give me a Zoom F3 with 32-bit any day.

Maybe I'm wrong, but it feels a bit easy to bash the safety track without giving any context.

Likewise, I think it's easy to praise a hypothetical while ignoring real world experience. The main track clipped in situations that had high dynamic range, so I'd default to the safety track, which was full of hiss. It was a mess of a recording that needing a lot of post work to get listenable. Glad to have the safety track, but I'd rather skip all that.

I didn't mean to disrespect anybody, and I'm sorry if I came across like that. High dynamic situations are a pain to deal with regarding setting the levels right. I have similar eperiences whith high dynamic shows (and no safety track feature on the recorder) where I was so scared to set the levels too high that I ended up with a recording with lots of noise in the quiet parts. I think in such a situation you could have had benefit from a little piece of software as described that could automatically merge the two tracks into one in a smart way, instead of manually merging or having to opt for the safety track that is noisy in the quiet parts.

I think your idea is interesting, but it hinges on two points:

(1) Are the R-07 preamps as good as the Zoom F3's? Your idea is all about optimising gain staging with the R-07, but your results will still be worse if the F3 provides cleaner gain. You could use a cleaner external pre-amp like most of us have done in the past, but then you add to bulk.

(2) How much work would it take to write a piece of software that accomplished what you're proposing automatically? Because doing it all manually would be a huge pain - not worth it at all unless you absolutely had to. If you are willing to actually write the software, though, it's a good idea!

[dallman]

For me, I enjoy that we often have varying opinions on just about everything. That is good, it helps us learn and grow and figure our own way.
This entire thread is interesting. I think the R-07 (and R05 too) are some of the best portable 24Bit decks on the market. Personally, I only used the safety track once, and I did not care for it, but it's a great feature for many in many instances.
I also will still record at 24 bit when appropriate for me. Some  situations especially. That is happening less and less, because more small 32bit decks are hitting the market and I really like not worrying about levels. When I tape live shows, I usually do not know what the sound level will be until the first notes are played. If I am off, can I fix it? Yes, but it is very nice to not even have to worry.
I am not a "spec" guy, I am an "ears" guy. I like what I like and pretty much respect anyone's opinion, but I will continue to evolve at my own pace. I started in 1971, and still learn all the time.
As I said, this is an interesting thread that shows how we differ and how we are alike.
Do I think an R-07 can become 32Bit? I do not, but I would be happy to be proved wrong.