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Sujet How to judge the quality of an unknown file - Page: 1

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MurrleyHome userMember since 2016
I have some mp3 and wave files but I don't know the source of them. I'm trying to find out if they're originals or compressed copies. Could someone explain how to do this?
 

Posté Sun 29 Jan 17 @ 8:48 pm
In Virtual DJ, right click the file, select tag editor, at the bottom will tell you the type and quality.
 

Posté Sun 29 Jan 17 @ 10:31 pm
MurrleyHome userMember since 2016
Thanks but that's incorrect for what I need.
 

Posté Mon 30 Jan 17 @ 12:46 am
trust your ears if it sounds bad it is bad simple
 

Posté Mon 30 Jan 17 @ 12:56 am
MurrleyHome userMember since 2016
It's not as simple as that. Any experts here?
 

Posté Mon 30 Jan 17 @ 12:58 am
locoDogPRO InfinityModeratorMember since 2013
Why isn't it that simple? It's djing not quantum brain rocketry, play it on a big rig [well a couple of kWs] or a set of quality monitors and listen
you can go down specral analysis route but to be honest that's being a bit precious either it makes the grade or doesn't and you should review your tunes this way anyway why create work?
Want the highest of quality tunes - simple don't use tracks from unknown sources.

 

Posté Mon 30 Jan 17 @ 1:19 am
MurrleyHome userMember since 2016
It's not that simple because I don't have access to a big rig or quality speakers, and I can't amp anything up where I live. I have tracks from beatport and juno that are clearly bad quality copies, so the source can be irrelevant. Believe me I'd really rather not create extra work, but in this case I can't do it by ear so I need another solution. It doesn't have to be totally exact.
 

Posté Mon 30 Jan 17 @ 1:30 am
VDJ RonPRO InfinityMember since 2010
I've been here before.
Anyway..Spek is a free program which displays information about the frequency range of a song. This can help detect inferior mp3's, but it only directs you to listen carefully to a questionable song, and then form your own opinion.

http://spek.cc/
 

Posté Mon 30 Jan 17 @ 2:31 am
MurrleyHome userMember since 2016
Thanks. I don't undertsand what you mean by, but it only directs you to listen carefully to a questionable song, and then form your own opinion. ?
 

Posté Mon 30 Jan 17 @ 2:41 am
locoDogPRO InfinityModeratorMember since 2013
voxengo span can be useful but time consuming you can see the high cut off between flac and mp3 320,

buy some reasonable quality headphones
 

Posté Mon 30 Jan 17 @ 3:40 am
MurrleyHome userMember since 2016
Decent headphones are a good solution and I'll be getting some in future. But can't just at this point in time. Will the sound be affected a lot without a decent sound card?

Is there a tutorial that explains how to visually tell by frequencies, for a beginner?
 

Posté Mon 30 Jan 17 @ 11:31 am
What are you currently listening to the tracks on? the laptop speakers? If so, you cannot rely on them. They could make a high res file sound bad.

An audio interface (external soundcard) will only help if you are going into top quality speakers really, and even then its not going to be that noticeable. The main benefit of one is that without one you could be suffering from latency issues, which can indeed make the audio of a track sound terrible. So the file could be fine and latency is causing bad audio.

At the end of the day, the sound will only ever be as good as the weakest link. At the minute it seems you have lots of weak links (in terms of sound quality) so the tracks maybe ok but the equipment is the issue.

There is no real quick way to visually discern a good or bad track, well not unless you are a producer maybe. I tend to mostly pay attention to the bitrate. If its less than 320 i delete it, I would rather not have it than play that and I will just download the flac version of it.
 

Posté Mon 30 Jan 17 @ 11:48 am
The simple answer is a good audio interface, a good pair of headphones and your ears.

I have some 128kps songs that sound fine and others that are horrible. It depends on the original compression and the dynamics of the individual track.

The only way to determine if something is good enough to play is by listening to it.
 

Posté Mon 30 Jan 17 @ 11:56 am
MurrleyHome userMember since 2016
Low quality desktop speakers. If I crank the volume to the max I can judge the quality closely enough for what I need. But that's not a option with my neighbours.

Can't tell by just looking the bitrate Andy as it depends on the source. As kradliffe says, I've also got 128kbps tracks that are much better than the 320kbps that I bought on beatport.
 

Posté Mon 30 Jan 17 @ 12:14 pm
Murrley wrote :
I have some mp3 and wave files....I'm trying to find out if they're originals or compressed copies. ?


True point about the source, but just going back to your original post...If its a WAV file then it is uncompressed. If it is an Mp3 then it is compressed. It is of course possible though that the WAV file has been re-recorded as a WAV file from an Mp3. Though this would have been a completely pointless exercise.

I am completely OCD about sound quality, so I see where you are coming from. What everyone has said about listening to it and deciding is quite right. There is no short cut really. But the only caveat i would give on that one is that you cant really trust what you are hearing, unless you are hearing it on top quality equipment. Some tracks may just have frequencies that your speakers cannot reproduce, or cannot reproduce accurately, so they will distort.
 

Posté Mon 30 Jan 17 @ 1:43 pm
bagpussPRO InfinityMember since 2003
You don't need top quality equipment, just a decent pair of headphones and the ability to pick out what you're looking for.

There was an online double blind test between 128kbps and 320kbps, I posted it on FB and many DJs who I respect for their experience and talent called the 128 as being the best source, they made the mistake of listening to the whole (MP3 is deceptive), to tell the difference you need to isolate the different frequencies mentally, which requires focused listening.

The lesson in this is that if highly experienced DJs can fail at a double blind test, then drunk/high kids in a noisy nightclub aren't going to be very reliable either. The "big system" thing is one of the big myths, the test is only as good as the listening enviornment and its subjects, both of which are massively flawed in the MAJORITY of DJ environments.

Of course this doesn't mean you shouldn't care, everytime you add a file, you should test it with headphones for any compression artefacts and distortion, and if you already have a massive library and find yourself playing a track that sounds substandard, simply delete it and make a note to replace it later, you'll probably find you were the only one that noticed.

 

Posté Mon 30 Jan 17 @ 3:33 pm
MurrleyHome userMember since 2016
I get you Andy. And while converting a wav from mp3 is pointless in theory, I'm sure it happens. I've bought wavs from old mix compilations that sound compressed compared to an mp3 of that track that I've managed to get. I doubt there are enough regs in place to ensure all the tracks on beatport, juno etc are master copies.

I'll be getting some HD25s and using my ears, but in the meantime I kind of need another option. By looking at the frequency could I tell if it's been compressed from a master file, to the point where it wouldn't sound good on a rig? And by comparing the frequencies of multiple files of the same track, could I tell which had been compressed the most? I'm sure that's easy enough, I've just never studied frequencies before.
 

Posté Mon 30 Jan 17 @ 3:51 pm
I think the things is though, that file compression (compressing a WAV to MP3) is a different thing altogether to audio compression.

All tracks when mastered will have had compression applied pretty much, even though the file hasn't been compressed. This unfortunately is where I reach the end of any useful knowledge on the subject though. There are a few people I can think of though on here that could probably help further. @groovindj being one of them.
 

Posté Mon 30 Jan 17 @ 4:03 pm
Without the source to compare to visualy no
All tracks have different frequency ranges.

 

Posté Mon 30 Jan 17 @ 4:05 pm
bagpussPRO InfinityMember since 2003

The quickest most reliable method would be to train your ears and listen, it's really not that hard. Meters are less reliable.
 

Posté Mon 30 Jan 17 @ 4:13 pm
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