More Fast Transfers

2013 May 7
by Simba
Unbelievable!!! by Aleera*, on Flickr
Creative Commons Attribution-No Derivative Works 2.0 Generic License  by  Aleera* 

I have previously discussed too fast transfers from 78s. Age Akkerman has a well researched take on Di Sarli’s El ciruja which he found to be about 5% too fast on the Euro Records transfer.

Rare Clips of Petróleo, Virulazo and others

2013 March 31

Amazing how these old clips slowly surface on youtube and facebook. Here are some clips that seem to be from an old documentary, posted by Victor Barrios and Cristina Benavidez:

HT: @FerGaleraTango

El Papa Francisco

2013 March 31
by Simba

Apparently the new pope is a tango lover, and now he got his own tango. Composition and lyrics by Daniel Ursini. Courtesy of  Canciones para grabar.

Happy Easter, Papa Fracisco!

HT @milongaroom

Carlos Di Sarli Documentary

2013 March 30

DiSarli

According to Realidad Bonaerense, there is a new documentary about Carlos di Sarli coming out, directed by Alberto Freinquel. No information about dvd or download edition, but there will be several public viewings in Buenos Aires and in Bahía Blanca, I think. The article mentions several dramatized sequences, which makes me a bit sceptical, but I guess you have to do something if there is little historical material available.

EDIT: A bit more information here.

BPM

2013 March 29
by Simba
Oil-wheel kick drum by Paul Graham Raven, on Flickr
Creative Commons Attribution-Noncommercial-Share Alike 2.0 Generic License  by  Paul Graham Raven 

The advances in DSP and processing power since I started ripping my cds to store all my music on a computer drive are enormous.

Sometimes having an estimate of the BPM of a tango song can be useful, e.g. when searching for “slow” milongas, sorting by BPM would be useful. But tapping each song individually to store in tags — no way it’s worth the effort. I remember doing some experiments years and years ago with automatic BPM calculation, and the results were useless.

Now, on the other hand, there are open source solutions available. The one I tried got good results, better than I could achieve manually, I think. I used Sonic Annotator with a vamp plugin from Queen Mary:

http://code.soundsoftware.ac.uk/projects/sonic-annotator/files

The command line I used was this:

 ./sonic-annotator -d vamp:qm-vamp-plugins:qm-tempotracker:tempo -w csv --csv-stdout ../test.wav

And I did a small script to calculate for my collection. I probably should have used different parameters for vals and milonga, but I haven’t had the time to try this out (it is already a long time since I did this, trying to cope with the blog post drafts queue).

TMP=$HOME/vamp/tmp.wav
flac -d "$1" -f -o "$TMP" 2>/dev/null
BPM=$(sonic-annotator -d vamp:qm-vamp-plugins:qm-tempotracker:tempo -w csv --csv-stdout "$TMP" 2>/dev/null |head -n 1 |cut -d"," -f3)
metaflac --remove-tag=BPM "$1"
metaflac --set-tag=BPM=$BPM "$1"
rm "$TMP"

In Sonic Visualiser I could have the software play along the detected beats to see if the timing was ok. Depending on your sense of humour, this could be a funny version of what seems to be my favourite test track: Al verla pasar + kick drum

Audio Restoration from Multiple Copies

2013 March 27

SprBroMorSapICASSP13-figure

I was pondering the usefulness of noise removal based on several copies of a recording, possibly from different physical copies. A Google search reveals that such a technique is already patented:

The present invention provides a method for reducing noise using a plurality of recording copies. The present invention produces a master file with lower noise than the available recording copies, and avoids the problems of losing musical content caused by prior art pop and click removers. The system comprises a recording playback unit, a computer system with a sound input capability, and a high capacity storage system such as a CD recorder. In operation, a plurality of recording copies of a single recording are played on the playback unit. These recordings are digitized by the computer and a separate recording file is formed for each copy of the recording. The recording files are then synchronized. The samples from each of the recording files are then averaged to reduce the noise components. A variety of threshold comparison techniques can be employed to eliminate samples and/or recording files that are outside of a computed range for that sample.

After doing a little more research I found the MATCH plugin for Sonic Visualiser, which sort of does what I had in mind, but I haven’t figured out how to process the aligned audio to get two aligned files:

This method is described in a 2005 paper by Simon Dixon:

Dynamic time warping finds the optimal alignment of two time series, but it is not suitable for on-line applications because it requires complete knowledge of both series before the alignment can be computed. Further, the quadratic time and space requirements are limiting factors even for off-line systems. We present a novel on-line time warping algorithm which has linear time and space costs, and performs incremental alignment of two series as one is received in real time. This algorithm is applied to the alignment of audio signals in order to follow musical performances of arbitrary length. Each frame of audio is represented by a positive spectral difference vector, emphasising note onsets. The system was tested on various test sets, including recordings of 22 pianists playing music by Chopin, where the average alignment error was 59ms (median 20ms). We demonstrate one application of the system: the analysis and visualisation of musical expression in real time.

I also found another paper by Pablo Sprechmann, Alex Bronstein, Jean-Michel Morel and Guillermo Sapiro who seem to do exactly what I had in mind. This is fresh stuff, and I found no reference to any available software implementation:

A method for removing impulse noise from audio signals by fusing multiple copies of the same recording is introduced in this paper. The proposed algorithm exploits the fact that while in general multiple copies of a given recording are available, all sharing the same master, most degradations in audio signals are record-dependent. Our method first seeks for the optimal non-rigid alignment of the signals that is robust to the presence of sparse outliers with arbitrary magnitude. Unlike previous approaches, we simultaneously find the optimal alignment of the signals and impulsive degradation. This is obtained via continuous dynamic time warping computed solving an Eikonal equation. We propose to use our approach in the derivative domain, reconstructing the signal by solving an inverse problem that resembles the Poisson image editing technique. The proposed framework is here illustrated and tested in the restoration of old gramophone recordings showing promising results; however, it can be used in other applications where different copies of the signal of interest are available and the degradations are copy-dependent.

If you happen to be in Vancouver in the end of May, you can attend their presentation at ICASSP 2013.

I’m curious as to how much difference this would make in practice compared with traditional statistical approaches. Theoretically, it would be very interesting for getting the most out of tango recordings where the masters are long gone and  would reduce less man hours for manual restoration. However, it would require extra effort as each track would have to be digitized from multiple physical copies, not to mention that you would need access to more than one physical copy of each recording. Something to think of for a project like TangoVia, that multiple copies of the same material might actually be useful.

Tango Tunes

2013 February 20
by Simba

BIAGI_5621_A

The first results are trickling down from the TangoVia project. Tango Tunes is a Vienna based organisation, digitizing music with the help from TangoVia. They recently provided a preview of what they will offer, and I have to say I think it sounds very good. The Troilo sample in particular was very promising. The first songs available for purchase are 100 Biagi songs.  The price is EUR 100, which is expensive compared with commercial releases, but cheaper than the Japanese labels.

What it comes down to then is selection and transfer quality. The really great thing is that they will offer lossless files in high resolution (96 kHz, 24 bit) for those that have time to spend restoring music. We others can just downsample to 44.1kHz, 16 bit. Unfortunately, Biagi is not high on my prioriy when it comes to repurchasing tango music. The commercial releases are already ok quality. Troilo on the other hand, will put me first in line. Same goes for De Caro, and probably also Di Sarli. D’Arienzo will also be interesting for many DJs, I think.

I don’t know how they plan on rolling this out later, but making complete discographies available would be another thing to make them stand out. I’m crossing my fingers for complete Troilo later this year.

 

 

El Corte Documentary

2013 February 19

I missed this when it came out. A doucumentary about the legendary El Corte in Nijmegen, The Netherlands. Eric Jørissen and El Corte have had a great influence on the European tango scene in general, and if I am not mistaken, on the tango marathon culture in particular.

HT: Veronica

Kung Fu Tango — Learning From Bruce Lee

2013 February 11
tags:
by Simba

–What is the highest technique you hope to achieve?
–To have no technique.

It is impossible not to think of tango, hearing some of the conversations in the Bruce Lee film Enter the Dragon.

–Kick me (Bruce Lee to one of his students)
student kicks
–What was that? An exhibition? We need emotional content. Try again.
student kicks again
–I said emotional content. Not anger. Now, try again. With me.
student kicks again
–That’s it,  how did it feel to you?
–Let me think…
slaps student
–Don’t think! Feeeeeeel!

My apologies to TP for ripping off some of his old fb posts (“I was learning tango from Bruce Lee”), but even if I have no clue about martial arts, I find it very intrigueing, and getting lost in procrastination research for this post,  I kept finding analogies with tango. There are great differences, of course, but the smooth movement, the groundedness, playing at the limits of balance… If you ever thought of giros and ganchos being metaphors of street fights as far fetched, have a look at the final fight between Bruce Lee and the Big Boss in The Big Boss (yes, I know). Some ganchos!

Martial arts using balance to trip the opponent over, tango challenging balance, only to make sure your partner is perfectly safe and on balance. I would be very surprised if a solid foundation in martial arts was not a great asset when learning tango. Or maybe rather taking up the practice of tango. In many ways tango is better thought of as a practice, rather than something you “learn”.

I’ve been watching several Bruce Lee films over the last months, including several documentaries, and it struck me that his moves seem so fresh, even today, more than forty years later. Indeed a testimony to the greatness of this icon of martial arts. The ballet like choreographies are, somewhat paradoxically very extravagant, in contrast to Bruce Lee’s philosophy of a minimalist martial art. The art of “fighting without fighting” as he says in Enter the Dragon. The screen tests he did before starring in Green Hornet were brilliant, and some of his demos from California likewise.

From the documentaries I learnt that Bruce Lee was actually a capable dancer, and won a Hong Kong Cha Cha competition, and earned some extra pocket money teaching dance at the boat to the US when reclaiming his US citizenship. One of the Kung Fu masters interviewed in one documentary told the story about how he made a deal with Bruce that he showed Bruce his Kung Fu tricks, and Bruce would teach him Cha Cha. –But after three nights, he knew all my tricks, and I never got beyond the basic step…

Bruce Lee was trained in a style of Kung Fu called Wing Chun, and there is a documentary on youtube about Wing Chun that seems authentic to me. Again the tango similarities jump at me. Maintaining center line, groundedness, pivots and relaxed, economic movement, and a technique called “sticky hands” where you keep contact with the opponent all the time with the arms to feel his next movement almost before he does himself.

This 10 year old practicing the Chen style of Taiji is also adorable:

I used to dismiss Taiji as old people moving slowly in the parks of Beijing to keep in shape. But if the old guys in the park are only a bleak shadow of ancient fighters, at the roots are real fighting. And like anyone who’s tried practicing tango in slow motion knows it doesn’t exactly make it any easier. In a completely other context I came over a saying that puts it nicely:

Slow is smooth; smooth is fast.

The break of rhytm is also a very interesting concept. This concept of establishing one rhythm and speed and then deviate from it as a surprise also works wonders in the tango.

I recently learned that one of my favourite directors, Wong Kar Wai (of “In the mood for love” fame), will release a Kung Fu epic called “The Grandmaster” based on the life of Ip Man, Bruce Lee’s teacher. El maestro del maestro. There is also a documentary about the making of this film, and the ordeals they went  through to get to the authentic Wing Chun, unfortunately not with English subtitles. And at this points we touch Argentina and tango again:

The documentary revealed that the idea of making ’The Grandmasters’ started in 1996 when Wong Kar-wai was working on ’Happy Together’ in Argentina. He saw a  local magazine with Bruce Lee on its cover and felt that the superstar’s influence on the world. Yet because the Bruce Lee story has already made many times, he wanted to explore Bruce Lee’s master Ip Man more and how he turned Bruce Lee into a legendary figure

Struggle to find the authentic, master of the master, does it sound familiar?

The trailer uses another phrase that resonates with a tango guy like me:

In his practice what I saw wasn’t movement, but essence.

I want to learn tango from Bruce Lee, too. Or rather, from Ip Man. El maestro del maestro.

Find One Error

2012 December 4
tags:
by Simba

This is a great idea! Trouvez l’erreur! from Les Pas Parfaits de Montréal. Simple, funny and well executed. Drawings by Véronique Paquette. My French is a bit rusty, but I believe the drawings are free to use for non-commercial purposes, and that it is allowed to translate them and incorporate translations in the images.

Makes me want to go to Montréal!