Can Bad Recordings be Fixed?

[fas42]

Decompression/Declipping ... yes! The experiments I did showed the potential, and I was merely feeling my way, purely explorative efforts. One pop track was just savagely compressed in the final mixing, and the parameters used in that operation could be deduced quite straightforwardly, from examining the waveform - applying the inverse of those parameters, in editing software that allowed uncompressing, did a nice job - there was no loss, from my POV, in the integrity of the track, but the massaged result sounded very much like a straight mix of the instruments.

 

Beware! There are plenty of utilities and such out there that claim to do things, but my experience of them is not good - I went back to basics, in analysing what could be seen in the waveform, and from that deduced what could be a good approach.

[fas42]

15 hours ago, Audiophile Neuroscience said:

 

What DAW did you use?

 

Reaper. Easily the most powerful I've come across, that's available to play with for zero cost.

 

Trying to mitigate the impact of compression without performing an undoing action with a high level of accuracy will be largely useless - all sorts of disturbing anomalies will be introduced. This is an exercise of performing serious analysis of the waveform, finding the patterns which mark the compression operation, determining what parameters were used in the software to create those patterns, and then applying an inverse operation. Using trival methods to try and 'fix' will yield trivial output, of little value for listening to, IME.

 

[fas42]

EQ is useless ... to me. All it may do is reduce the apparent level of annoying artifacts introduced by less than optimal playback. We have all had lousy radios playing with screechy, distorted high frequencies - easy fix, wind down the Treble - nothing's been resolved, we're just making the ugliness less noticeable.

 

Only real solution is to eliminate the ugliness - which is not the recording, but how the playback mishandles "troublesome" content. The attitude to have is that the recording is always fine, but the playback can't cope - "you can't handle the truth!!"

 

The big plus is that the 'difficult' recordings often end up becoming the most rewarding, because the intensity and richness of their content delivers a more powerful, emotional experience.

[fas42]

The Plangent Process looks good, in that it undoes the wow and flutter embedded in the analogue master tapes - filling in of "missing frequencies" is a question mark though ...

[fas42]

30 minutes ago, CuteStudio said:

 

The problem that the record companies give us is that each track is mangled in a different way, even on the same album exactly the same mangling process is rare.

...

 

Which is why today if you want to hear a decent CD you generally have to dig out some old (mastered in the 1980s!) Floyd etc.

BTW. 

 

So you're the man behind SeeDeClip ?!

 

I looked at that program about 6 years ago, when investigating my options for "fixing" tracks. I can't recall what the results were like, using the utility at that time - but ended up doing it "my way", back then. Perhaps I should have another look at the latest version ... ??

 

[fas42]

13 minutes ago, sandyk said:

A couple of Sound Forge 9 screen grabs of "Better Be Home Soon - Best Audiophile Voices 2"

One is the original, and the other is newly created using SeeDeclip Duo Pro.

 

 

 

 

Hmmm ... unfortunately, I don't see in that too much undoing of compression effects, more just straight declipping. Which is what I found when I investigated the software back then - the algorithms didn't have the ability to analyse what had been done to the track, and couldn't do sensible reversals.

[fas42]

Just now, miguelito said:

 

What tools have you used for decompression? I fear that compressed music has also a lot of clipping, which would make decompression impossible.

 

As mentioned above, the main software I used was Reaper - every track, album will be different in how it's been 'mangled', and I used a combination of visual inspection, intelligent guessing, and trials around the likely parameters for best results. From memory, I declipped, then decompressed - on the few tracks I played with seriously I was pleased with with what I got out of them - but I certainly knew that the compression settings could get very fancy with some material, and that it would be a major exercise trying to work out what had been done for those.

 

What I took away from the exercise was that it would be possible to do the analysis, if one had plenty of time, and motivation - do it with software, rather than manually; just build up the sophistication of the unravelling algorithms, over time, until most anything could be 'repaired'.

[fas42]

8 minutes ago, miguelito said:

 

.... If there is clipping, then you’re screwed as that loses info.

 

Info may be lost, but it's extremely transitory. Interpolating, guesstimating, copy and paste from similar parts of the waveform can do a lot - my belief is that reversal of vicious clipping could be finessed to the point where losses were essentially inaudible.

[fas42]

8 hours ago, miguelito said:

 

Very interesting on clipping. I would have thought clipping was basically the end of the road.

 

I can certainly imagine someone coming up with software that would analyze the entire track - probably making some assumptions on the compression type used - and estimate compression parameters. Maybe a few different variants for the user to select and listen for the most “natural” result. I can certainly see a possible use as a DSP plugin in some players (Roon for example).

 

 

 

When I was exploring, that's essentially what I was doing - a smart guesstimate, done manually, using largely visual clues, and then iterate to "just right". On either side of the correct settings, the sound was "peculiar"; get it right on the button and everything would sound "normal" - it was also possible to see the "sweet spot" visually; the waveform would not show an awkward shaping to the envelope of the peaks.

[fas42]

57 minutes ago, sandyk said:

 Hi George

 Even my older version of Sound Forge, (SF9) permits Expansion at various ratios.

 You wouldn't expect the freeware Audacity version to have a module like that.

 

Regards

Alex

 

 

It is possible to directly use Audacity - Reaper makes the set of plug-ins available for download, which includes the key compressor module. I've installed these, and they work fine.

[fas42]

Just now, sandyk said:

 

 

And the price ?

 

A very nice, zero!  ...

[fas42]

And here you go, https://www.reaper.fm/reaplugs/ ...

[fas42]

13 hours ago, sandyk said:

 I have available a DL of before and after versions of a complete track in .wav format, using SeeDeclip Duo Pro,  if anybody is interested to see if they can hear any difference from before and after. The track had only minor clipping, although the posted waveform suggests otherwise. The differences are quite subtle, and you will need to increase the level of the declipped version by a couple of dB.

PM me if you would like the DL  links.

 

I have had a look at sandyk's offering, and to my eyes this looks like classic compression - of the sort that I looked at some years ago. Audacity reports zero clipping of the before, and technically this may be the case - but the dynamics have been savagely squashed, by about 10dB from eyeballing the waveform.

 

The SeeDeclip fix only slightly rectifies this, by about 1.5dB - I think I might have a go at refreshing my techniques, and try and do a lot better than this, on this particular posted track, . If I think I've got somewhere, I post it up, and invite criticism ... .

[fas42]

8 hours ago, miguelito said:

 

Geezus Xist! That’s a lot of work!

 

I wasn't fussed ... . The point, for me, was to see if it could be recovered, using a logical, iterative approach - which did work out. Obviously, this would be madness if every single recovery process was completely manual - but it means that intelligent, analysing algorithms could be devised ... the next step, one day ...

[fas42]

2 minutes ago, gmgraves said:

 

But still, no expander function that I can see. The compression ratio control, starts with 1:X, See no control marked X:1.

 

Look at ReaXcomp - the ratio goes either side of 1:1.

[fas42]

Just to mention, I'm making better progress that I thought I would!  It's been ages since I've done this, but it's coming back to me ...

 

Instruments are a big improvement, now getting the sweetness through - the 'recovery' is at a point where the variation between right, and not right, is in a fine balance - in the end, one gets the "right numbers", and none other are better - shouldn't be long!

[fas42]

Hmmm, I slowed down a bit - had a heavy session with the dentist yesterday, and wasn't feeling brilliant for a while ...

 

Anyway, to get a feeling for what before and after waveforms can look like, here's sandyk's original version, attenuated by 7dB:

 

 

and the restored waveform, latest effort:

 

 

Pretty close to optimum, but I still want to play around with it a bit more; there's a slight volume pumping I want to eliminate.

[fas42]

Since I've got a couple of eagle-eyed recording engineers watching on, I'd better get this worked over track in pretty good shape before presenting it, - so, I might play with it a bit longer. Busy for a day or so, then I'll do another round of fiddling ...

[fas42]

1 minute ago, sandyk said:

 Hi Frank

 Although you are likely to be able to obtain worthwhile improvements with this particular track, it was far from a basket case,  with very little clipping in comparison with many modern recordings.

 Unfortunately, the results that you achieve may not lend themselves to using the exact same method for "correcting" the whole album , which many members would find quite acceptable as it is.

Unless we develop automated methods for Batch tasks, there will be far too much expenditure in time involved.

I believe that Graham Wilkinson from Cute Studios (I hope I got the name right ?) did a fine job in developing a program that was able to make many annoying recordings of the time more listenable.

Kind Regards

Alex

 

No clipping, but quite severe compression. The improvements are major in terms of the quality of the instruments, the voice less so - what the compression does is cripple the sparkle and texture of the track, something which is important to me; so I'm happy to to expend some thought in reversing that.

 

In an album, if the sound engineer has some integrity he would tend to use the same processes on all the tracks, so that there is some consistency to the style of sound. So, a solution for one may set the pattern for all.

 

Of course automated methods is the answer, but the first step is manually, laboriously refining a procedure which really gets the job done - the learning curve is all-important, not the you beaut push the magic button and out pops a pristine track.

 

I looked at CeeDeClip about 6 years ago, and felt that better could be achieved. The latest version may be much improved, so I will take a closer look at it.

 

Cheers,

[fas42]

2 hours ago, sandyk said:

 Hi Frank

 You are unlikely to be able to do that with this particular series of 7 albums,(Best Audiophile Voices)  as they were sourced from many different albums, and remastered at a higher resolution before being converted to 16/44.1 again.

The originals would most likely have been engineered by different recording and mastering Engineers. 

 

Regards

Alex

 

And of course compilations are in a completely different basket - what really got me going in this exercise was a freebie CD, which had a bunch of theme songs, from TV shows. There was one in particular, which worked on the tiny speakers on the box - but played back on a fairly decent setup the sound was incredibly aggressive - a "take no prisoners" quality to it. Surely the musicians, a classic garage rock band, didn't sound like this in the studio? And indeed it had been given a quite simple, but heavy duty compression treatment - which could be reversed quite straightforwardly ... ahhh, real music !!!

 

The giveaway when reversing is weirdness in the sound, or volume pumping - all traces of that need to be excised, to call the exercise a success.

[fas42]

Just to say, I haven't given this away ... as usual for me, once I start getting into something I instinctively go deeper and deeper - so I have been sidetracked into looking into my old efforts, from years back, and checking what's happening out there in Net land...

 

The Better Be Home Soon track has been soft limited, a specific type of compression - I can go from the original to the mangled version from the Audiophile Voices album almost perfectly; the trick is now to go in the other direction, which is what I'm looking at at the moment.

[fas42]

4 hours ago, CuteStudio said:

 

Thank-you!

Caveat: The last time I suggested someone try my software on CA I was told I'd be banned if I did it again, so I've stayed off this thread and I'll be trying to keep any comments VERY non-product specific. Banning seems very popular these days in all forums about all subjects so it's impossible to have a robust conversation that would have been the norm 20 years ago, so I'll try to keep it very PC and wishy washy as if I didn't really care about the subject.

It's also a bit long as a post, but that also means I won't have to post for a while again too.

 

 

Thanks for posting your ideas on the matter! I haven't digested them as yet, but will do so shortly - and most likely respond.

[fas42]

7 minutes ago, semente said:

 

No.

 

The answer is vastly more than a simple No, or Yes. First of all, why is the recording "bad" - was the equipment used in terrible shape, of poor quality, and imposed a strong distortion signature on the end result; or was the recording gear of superb quality, the best one can buy, but the mastering "mangled" the raw inputs? There is a huge spectrum here, and the solutions will, or may vary per recording.

[fas42]

Just now, semente said:

 

I agree that the effectiveness of the "treatment" is inversely proportional to the "disease" (and it's also genre or better programme specific).

That's all.

 

The degradation starts from the mic onward and any editing of the signal will take its toll.

Mixing and EQ'ing included.

 

Yes, degrading will always take place - it cannot be otherwise, because of the nature of the universe; unless the source is purely digital in form a perfect replica can't be captured. However, the "great miracle" is, that if all due care is taken, with possible 'correction' of the captured data, and then the absolutely highest standard for the replay setup, that subjectively any flaws that can't be easily eliminated matter not one iota - the listening experience is as full, vital, powerful, emotional, as one could wish for - and isn't that the point? Anyway, such is the case, and the goal, for me.

[fas42]

3 hours ago, gmgraves said:

I don't particularly like pop and rock, Never have, but there are exceptions. I first heard Santana's "Abraxes" recording as a playback in the Wally Heider recoding studio in San Francisco in the early '70's. I was quite taken aback by "Oye Como Va" through Heider's huge JBL monitors in their main control room, The cleanliness of the electronic organ and the purity of Clarlos' electric guitar (without a fuzz box or wa-wa, or any of the other things that make electric guitars my version of the worse sound on earth!) really impressed me. After that, I never minded hearing that piece or Black-Magic Woman. Recently, seeing that a 24/96 version of "Abraxes" was available on HDTracks, I decided to spring for it, thinking that I'd finally have access to a copy of the master that sounded at least as good as the playback I heard at Heider's studio back in the day. Boy was I gypped! the "high-res" version sounded exactly like the recent RedBook CD of the album that a friend brought over so that we could compare - lousy, both of them! (if you haven't heard the master - even through a pair of TERRIBLE JBL studio monitors*, you probably don't know how good the master tape was!).
 

 

Sometimes it's the surprising recordings that get it together - I've mentioned elsewhere an album by Alligator Records, Hound Dog Taylor - A Tribute ... house rockin' blues. The dynamic bite and life of this is something to behold - I haven't tried analysing the waveform, but subjectively it feels like it's mighty close to the raw feeds of the microphones, and nothing else.