[Everman]

Solaris,

Which payment methods are those? I tried the txtNation solution in your announcement, but I don't see any PayPal options popping up when selecting credit/debit. Is there another one working somewhere?

[Frunze]

Originally Posted by solaris

That they will do - no question - but that is not upgrading a file from 192 kbps to 320 kbps and expecting to be compensated

We actually asked them (late last year), if they would consider such a service in the future (upgrading and paying a little extra) and they said that they'd think about it. I guess they're still thinking

Just like they're thinking about making payments actually easy on their site.

[Erick Larson]

I also think that you won't get the imbursment. But I guess it's time for me to stop thinking that not every company have bad after sales service.

[pcspecialist]

>>>Now...to see if my ears can tell the difference between 192 and 320<<<

With a good subwoofer and your crossover set correctly you might hear the difference but unlikely because 192 is a reasonably high bitrate. A 128 to 320 comparison would likely be fairly noticeable.

I'm guessing they reimbursed because the software overwrote your original file without warning - not because you upgraded to a higher bitrate file.

[RedSmurf]

Originally Posted by pcspecialist

>>>Now...to see if my ears can tell the difference between 192 and 320<<<

With a good subwoofer and your crossover set correctly you might hear the difference but unlikely because 192 is a reasonably high bitrate. A 128 to 320 comparison would likely be fairly noticeable.

I have my doubts about this. Very low bass frequencies take so little information to represent faithfully that there's not much to be gained by leaving them out. On top of that, human ears are not very sensitive to low frequencies (both considering amplitude and frequency variations), so they can be approximated, further reducing the amount of required information. Lossy encoders will not alter the low frequency content unless you go to ridiculously low bitrates. To illustrate this, I encoded a piece of pink noise (which has the same power spectrum as "average natural sounds") at various bitrates, using LAME. I plotted the spectrum for the original and the encodings. The result can be seen here:

As you can see, the lowest frequencies stay intact. LAME automatically lowpass filters the sound at low bitrates, but even when I disable that option, you can still see that the low frequencies stay unaltered while the high frequencies are butchered:


So when evaluating bitrates, you should focus on trebles, by using speakers with good tweeters, or good headphones. But you'll need good ears indeed to hear much improvement from 192kbps on.

[pcspecialist]

Originally Posted by RedSmurf

LAME automatically lowpass filters the sound at low bitrates

Question: Why use a lowpass filter when low frequencies take up so very little space.

Answer: Low frequencies are extremely unforgiving and music sounds better with the low frequencies discarded rather than applying much lossy compression.


Nearly every time I'm given an MP3 encoded at a lower bitrate I get comments about something being wrong with the subwoofer/s yet no comments on the rest of the system. Maybe it is because people are used to hearing low bitrate MP3s on average systems but I can't make the same claim for myself as I've had a sub longer than MP3s have been around. I've also noticed the larger the venue, the more apparent it seems to be in the low frequencies.

Originally Posted by RedSmurf

On top of that, human ears are not very sensitive to low frequencies (both considering amplitude and frequency variations), so they can be approximated, further reducing the amount of required information.

Human ears may not be very sensitive but the entire human body is. I seem to recall an advertisement way back when, "with our subwoofer you do more than listen to music, you EXPERIENCE it". That's not word for word as I don't remember it word for word but I do remember thinking to myself how absolutely correct the concept that adding a sub to a system will allow you to "experience" music. Maybe the human body is more perceptive to the effect of lossy compression than the human ear.

Heck, while creating a playlist for tomorrow, I came across a MP3 encoded at CBR 192 (from LegalSounds) that just didn't seem that great so I looked for the same album with allTunes to find they had it and downloaded it using the extreme setting and did a blind test between the two and the extreme had a most definite different feel. I'll admit that many other blind tests with other MP3s (CBR 192 compared to higher VBR) are hard to tell the difference.

[RedSmurf]

Originally Posted by pcspecialist

Question: Why use a lowpass filter when low frequencies take up so very little space.

Answer: Low frequencies are extremely unforgiving and music sounds better with the low frequencies discarded rather than applying much lossy compression.

I don't get what you're trying to say here. A lowpass filter does not discard low frequencies. It keeps them.

If a considerable reduction in file size could be achieved by leaving out the lowest frequencies (which is not the case), the designers of lossy codecs would certainly have dropped them at low bitrates. For practically all normal music they are just a nice extra, but non-essential. If you'd need to reduce a song to its most essential description, you certainly wouldn't say "a 32Hz tone there", you would focus on frequencies that make up actual musical notes and voices. Many songs don't even contain anything significant below 50Hz.

The fact is, MP3 doesn't even know about ultra-low frequencies, because its frequency resolution is too small. The window size (1152 samples/channel) is too small for even a single cycle of anything below 38Hz to fit in. So those frequencies are actually described by combinations of higher-frequency components and a DC offset. This is another reason why there's little to be gained by dropping the ultra-low frequencies. But, it also means that for the MP3 encoder, each frame containing such frequencies will appear to contain a bunch of higher frequencies instead. If it's impossible to encode all those frequencies accurately, extra noise will be introduced. But the amount of distortion would need to be huge before the amplitude or frequency of the low frequency wave itself will be significantly altered.

So what I'm trying to say here is that even when encoding at low bitrates, sub-bass sounds will not be easily dropped, they will mostly be augmented with noise in the higher bass range. This could give a different sensation when using a subwoofer, though. But if you have never heard (or felt) the original song, you will most likely not notice anything unusual about the bass, whereas the typical jangling 'glass shards' distortion on the trebles is mostly immediately recognizable even on songs you've never heard before.

If you're still convinced that low bitrate MP3s drop the lowest frequencies, then you should download this sound. It's a sweep going from 16Hz to 1600Hz, and it's encoded at a measily 48kbps (mono). Even at that bitrate, the difference between the encoding and the uncompressed sound is practically zero. The only noise (audible after amplifying the difference by at least 20dB) is in the part around 1kHz. The low frequency part does get polluted with extra frequencies when the same sound is encoded with extra noise added. But the low frequencies themselves are still present even at the lowest possible bitrates.