D02 Classical guitar lesson 07

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Mariano Martínez Gallego
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Re: D02 Classical guitar lesson 07

Post by Mariano Martínez Gallego » Sun Feb 23, 2014 7:19 am

Hi colleagues, using a translator, my expressions can change, and want to say white he translates it as black. And it changes the meaning of what was said.

For that I ask you, me excuses, if you understand something, just a message and change it.

A greeting
Mariano.

Note: Everything can be changed.
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Marko Räsänen
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Re: D02 Classical guitar lesson 07

Post by Marko Räsänen » Sun Feb 23, 2014 8:08 am

Hi Carl,

I would suggest that you do not use the auto-gain feature of your recorder unless you really have to. The beginning your improvisation recording is clearly clipped, and your recorder only adjusts the gain after a second or two. See the atttached screenshot for visual confirmation.
clipping.PNG
Regarding Bea's observation that your mp3's sound better, I have made a similar observation about my own recordings at some stage.

I think quite a bit depends on the process of making the video. I don't believe that uncompressed audio is supported by youtube, so it means that either movie maker or youtube itself is applying lossy compression to audio. In the worst case both. Youtube is also suspected of (or at least at some stage was suspected of) applying dynamics compression to the audio. When I now upload audio compressed with AAC@206kbps@48kHz into youtube, I get back (when I download the video mp4 from YT) AAC@192kbps@44.1kHz. I don't know why does youtube change the sampling rate, but close visual comparison in a waveform editor does not reveal any differences in dynamics. I haven't found a way to overlay the two waveforms perfectly, but naturally there would have to be differences caused by resampling, and I guess that would have to mean recompression as well.

What I learned in the past was that the poorer the audio bit rate I used for uploading into tube, the poorer bit rate youtube would use when it recompresses the audio. So it makes sense to use a high enough bit rate for the audio of the uploaded videos, because two times compressed with a poor bit rate makes the quality suffer twice.

If you save the video into a file instead of uploading directly into youtube from movie maker, you should be able to see in file properties, what is the audio bit rate of the resulting video, though you may not see the audio codec used for compression without a video editing program (at least MPEG_StreamClip will show you that). Or you could just download one of your recent videos from youtube (using video manager), and see what the audio bit rate of the file is.
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Mariano Martínez Gallego
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Re: D02 Classical guitar lesson 07

Post by Mariano Martínez Gallego » Sun Feb 23, 2014 9:52 am

Interesting argument Marko.

You tried to upload it to VIMEO.


A greeting
Mariano.

Note: As you say, much depends on the Publisher with which you record it, then with that you upload it, then where you upload them, and finally that you play it.

Surely there are good teams to correct this, but they will be very expensive.
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Mariano Martínez Gallego
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Re: D02 Classical guitar lesson 07

Post by Mariano Martínez Gallego » Sun Feb 23, 2014 10:09 am

Hi Laura

As you did you put two videos on one single, is magnificent.
http://www.youtube.com/watch?feature=pl ... sFOdnT5BUU

A greeting
Mariano.
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CarlWestman
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Re: D02 Classical guitar lesson 07

Post by CarlWestman » Sun Feb 23, 2014 5:12 pm

Marko Räsänen wrote:Hi Carl,

I would suggest that you do not use the auto-gain feature of your recorder unless you really have to. The beginning your improvisation recording is clearly clipped, and your recorder only adjusts the gain after a second or two. See the atttached screenshot for visual confirmation.
Marko - thanks for the tip, you are right, and I did notice in Audacity that it was getting clipped at the beginning. I'm going to switch back and make some manual recording level adjustments. I recently switched to the AUTO because I noticed how low it was recording, and thought AUTO might do better to get the guitar without amplifying background sounds. Guess not. Also, being close to the mic (within arm's reach) probably lends itself to being overwhelmed with a well-struck bass note.

I just checked the file properties on some of my videos and audio only stuff.

MP3 is being encoded off WAV at 256 kbps, but when wav is used to overdub AVI audio in the windows movie maker, it's coming out at 192 kbps. I still thought that such differences were well out of the range of human detection. Anyway ... Thanks and I'll adjust my recorder, settings.

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CarlWestman
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Re: D02 Classical guitar lesson 07

Post by CarlWestman » Sun Feb 23, 2014 5:14 pm

PS Awhile back I tried Vimeo briefly but they had a limit on HD uploads such that I would have to pay to upload more than 1 HD video a month or so. Perhaps they've changed that, but it led me to stick with youtube.

Stefan Srećković

Re: D02 Classical guitar lesson 07

Post by Stefan Srećković » Sun Feb 23, 2014 6:24 pm

That and they've got some god damn long processing queues. Or at least they used to.

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Marko Räsänen
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Re: D02 Classical guitar lesson 07

Post by Marko Räsänen » Mon Feb 24, 2014 8:01 am

CarlWestman wrote:Marko - thanks for the tip, you are right, and I did notice in Audacity that it was getting clipped at the beginning. I'm going to switch back and make some manual recording level adjustments. I recently switched to the AUTO because I noticed how low it was recording, and thought AUTO might do better to get the guitar without amplifying background sounds. Guess not. Also, being close to the mic (within arm's reach) probably lends itself to being overwhelmed with a well-struck bass note.
I could be wrong, but my understanding is that 'auto-gain' works by detecting peak sample values in analog to digital conversion, and lowering the gain of the analog signal every time that the maximum digital sample value is reached. Optionally some auto-gain implementations also increase the gain when after certain time a certain sample value threshold isn't reached. Gain (auto or manual) should not have any effect to 'guitar sound to background noise' ratio, unless some kind of dynamics compression / limiting is coupled with the gain. The used gain setting could however affect the level of the hiss produced in the signal path inside the recorder. The only way to eliminate background noise (without digital noise gate or noise cancelling processing, which in my opinion destroy the fidelity of the recording) is to place the microphone close to the guitar. The farther it is from the guitar, the more room reflections and background noise there will be in the recording. Placing it too close to guitar then again enhances the string noise, could make the bass response boomy, and otherwise reflect the sound of the instrument in bad way, so there is always a trade-off involved.

A simple way to continue using auto-gain could be to strum a really loud chord right after you start recording, which will adjust the gain, and then just edit the chord out from the final recording. This is pretty much assuming that your auto-gain works only one way (decreases gain).
CarlWestman wrote:MP3 is being encoded off WAV at 256 kbps, but when wav is used to overdub AVI audio in the windows movie maker, it's coming out at 192 kbps. I still thought that such differences were well out of the range of human detection. Anyway ... Thanks and I'll adjust my recorder, settings.
An uncompressed CD quality WAV should be 2 (channels) * 44100 (samples per second) * 16 (bits per sample) which is approximately 1400kbps, and since the mp3 you posted was 128kbps, so I am wondering what does that 256kbps refer to? Are saying that you're encoding the audio into 256kbps mp3 before using it to overdub in windows movie maker?

I agree with you though that 192kbps stereo stream with any reasonable compression algorithm should be virtually indistinguishable from 256kbps and the original WAV. 128kbps is starting show some degradation in higher frequencies (not that I could identify that in a blind test), but for someone to say that your mp3's sound better than your videos (without being able to compare the same sample), and if the only difference between the two was the audio bit rate, the audio bit rate in the video should be well under 100kbit/s, possibly somewhere round 50kbit/s considering that CG recordings have very little high frequencies present, which are the first to suffer when the bit rate goes down.

So, if there is a consistent difference between the quality of your audio only recordings and your videos, I would guess that it is caused by something other than the bit rates.
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Laura Staats

Re: D02 Classical guitar lesson 07

Post by Laura Staats » Wed Feb 26, 2014 4:05 am

Thanks to Mariano for visiting our forum and offering feedback on our lessons. I enjoyed trying to read the original Spanish text, and appreciate your comments.
Marko has some excellent listening skills. If a recorder is set to auto levels and keeps adjusting throughout the piece, it can really mess up the dynamics of a performance.

Mariano Martínez Gallego
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Re: D02 Classical guitar lesson 07

Post by Mariano Martínez Gallego » Wed Feb 26, 2014 7:17 am

Laura Staats wrote:Thanks to Mariano for visiting our forum and offering feedback on our lessons. I enjoyed trying to read the original Spanish text, and appreciate your comments.
Marko has some excellent listening skills. If a recorder is set to auto levels and keeps adjusting throughout the piece, it can really mess up the dynamics of a performance.
Hi Laura.

I thought that did more reviews in this forum.

You give great importance to the recordings and sound.

In our forum comments are more focused towards beginners.

Here all know very good touch.

I invite you to paseis by the Spanish Forum, you will see some small differences in the approach of the course.

Greetings Laura.
Mariano.

Note: Forgive, not be English, but gradually learn.
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CarlWestman
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Re: D02 Classical guitar lesson 07

Post by CarlWestman » Thu Feb 27, 2014 2:40 am

More submissions

Here are a couple takes on Ecossaise, one with nails and one without. I have almost always played without nails, but lately I let them grow and shaped them a bit. I'm not going to be coy and quiz you on which is which (but if you want to quiz yourself, don't read the description on the youtube page!). I think it'll be obvious - most of my efforts with nails produced extra string noise here and there, and although I was able to minimize that in the one here, I did catch the nail on a string and produce a lovely twang (as I often did when I tried before, that's in part why I gave it up). So I trimmed them and did a different take. If I had to choose one as an official submission, I guess I'd choose the one with flesh, though without that one twang, I'm not sure I would.

That said, I had done this whole lesson with nails until today, and when I trimmed them back, it felt very weird! I had already gotten used to nails, even if I wasn't as good with them yet.

Giuliani – Écossaise n. 10 opus 33 en la mineur (version X): http://youtu.be/zJd-P5Yp5X4
Giuliani – Écossaise n. 10 opus 33 en la mineur (version Y): http://youtu.be/pUtJjnyo6LA

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CarlWestman
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Re: D02 Classical guitar lesson 07

Post by CarlWestman » Thu Feb 27, 2014 2:43 am

oh, maybe I might as well submit these MP3 files too, for comparison.
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Re: D02 Classical guitar lesson 07

Post by CarlWestman » Thu Feb 27, 2014 2:46 am

Marko - looks like I was wrong, my mp3 files are being encoded at 128 kbps. I can change that going forward (actually I have all the original WAV files, so I can re-encode any of them to 192 kbps). I'm not sure where I got the 256 figure. Anyway, when I do the movies, I take the video with its audio, add the WAV file as music, and then change the audio mix so that it is 100% the WAV file and 0% the original (crummy) audio from the camera. But then, in the process of exporting it to wmv file format, something happens.

Mariano Martínez Gallego
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Re: D02 Classical guitar lesson 07

Post by Mariano Martínez Gallego » Thu Feb 27, 2014 5:13 am

.
Last edited by Mariano Martínez Gallego on Thu Feb 27, 2014 5:15 am, edited 1 time in total.
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Mariano Martínez Gallego
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Re: D02 Classical guitar lesson 07

Post by Mariano Martínez Gallego » Thu Feb 27, 2014 5:13 am

CarlWestman wrote:oh, maybe I might as well submit these MP3 files too, for comparison.
Hello CarWestman.
l
Hear your two recordings.

Escuentro not too many differences between them.
Linked sound good. maybe a little weak. But that sound is important.
Off, if you can enhance them, if you go a little more slowly,'d win a lot in cleaning sound.
Very good pace.

Points to improve:
Mark difference between "p" and "f", you make two very evenly, you diferencialas a little, very fluid your litter.

comment:
If some chisquirrios, displacement noises are heard on the ropes, but as comets may be the fingers.

Nice to hear, sounds great.

regards
Mariano.

Note: Translated by google, sorry if you do not understand something.
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