[eahm]

The magic comes when you try AAC or Opus and you go down to 64kbps with some songs and you don't hear the difference with good headphones. Then you cry.

 

[bigshot]

I'm assuming that the higher ohms just resist the hissing noise more

What hissing noise?

 

[joeyjojo]

Quote:

thank you for this post, it was just what i was looking for. id like to add a related question, if i may.
would the Impedance make any difference? i know that whether or not Impedance makes any difference at all is also a source of much debate, but still, would a higher Impedance be less "forgiving" and make the difference more apparent? would finding these small difference between bitrates be easyer with 250 ohm cans? how about 600? 

 
All the impedance does is change the distribution of voltage and current.
 
What will make a difference is the sensitivity of the headphones. High sensitivity headphones will reveal more noise as the SNR ratio suffers (think IEMs plugged into a noisy front panel audio socket on a computer. The whining noise has a constant power, which turn into a much larger SPL through sensitive earphones than low sensitivity ones).
 
This is a constant noise though, not for "artefact hunting". There's no reason I can think of for one headphone to be more revealing of compression artefacts than another.

 

[BoxerOrBag]

can somebody please tell me if this site's test is accurate/fair?
 
http://mp3ornot.com
 

 

[mikeaj]

Quote:

This is a constant noise though, not for "artefact hunting". There's no reason I can think of for one headphone to be more revealing of compression artefacts than another.

 
I think for mp3 and some other formats and encoders, the artifacts are mostly high frequency.  A treble-tilted headphone would make those things easier to hear, with less auditory masking of the problems I guess.
 
With a low enough bitrate and certain preset and young enough ears, you could detect the presence of the lowpass filtering, which should be easier with headphones with good treble extension.

 

[stv014]

It seems to be so mostly, other than the minor level mismatch noted below. Also, the delay before playing "X" is relatively long, but maybe that is intentional.

 

[xnor]

Quote:

can somebody please tell me if this site's test is accurate/fair?
 
http://mp3ornot.com

Yes it is.

 

[stv014]

I found some level difference (a few tenths of a dB) between the pair of files I downloaded.
Edit: I tried another pair of files, and the 128 kbps version is again slightly quieter.

 

[Lorspeaker]

Quote:

 
Anyways, I have tested this on my Computer + Asus Xonar STX and iPhone -> FiiO E11 using both the Monster Miles Davis Tribute, Monster Turbine Pro Gold, Beyer DT770, and Beyer DT990.
 
 

 
 
errrr.....do u think a dedicated dac would help u separate between the diff resolution?

 

[stv014]

Quote:

errrr.....do u think a dedicated dac would help u separate between the diff resolution?

 
The DAC on the card degrades the signal much less than 128 kbps MP3 compression, probably not even audibly at all, so most likely no. Although maybe some "audiophile" DACs distort the sound in a way that somehow makes the difference more noticeable.

 

[BoxerOrBag]

Quote:

Yes it is.

THANK YOU very much

.
 
On a completely unrelated note, I'd just like to mention that while I've just recently made my account, I have been browsing this forum for close to a year now. I would now like to take the opportunity to thank all the gracious folks who's been sharing the knowledge on the Sound Science forum, it really helped me learn about not just the gear, but my senses as well.

 

[xnor]

Quote:

I found some level difference (a few tenths of a dB) between the pair of files I downloaded.
Edit: I tried another pair of files, and the 128 kbps version is again slightly quieter.

 
Slightly quieter in rms level but actually louder (EBU R128 loudness). My guess is that the guy that created the files used a ReplayGain scanner to normalize the volume.

 

[stv014]

I have now checked the files with ReplayGain in foobar2000, but it also shows the 320 kbps version as being a few tenths of a dB louder.

 

[xnor]

Yes, fb2k switched to a r128 compliant loudness scanner some versions ago. For example the 320 kbps Gino D'Auri track needs 0.37 dB more attenuation than the 128 kbps version to have equal loudness. One would have to check with an older fb2k version or mp3gain to see if they were normalized at all or based on the old proposed RG standard.

 

[streetdragon]

i got pretty interested after reading this article

free download link is here available in FLAC and others http://wolfgun.bandcamp.com/track/voyager

so I decided to run a little blindtest on myself, i took this song in FLAC into sound forge and saved it as:
FLAC x1
320mp3 x2
128mp3 x2
32mp3 x1
HighVBR x1
MediumVBR x1
LowVBR x1

placed them into winamp and randomized them, and did a blind test
guess answers on the left, real answer on the right

128mp3/MVBR - HVBR
320mp3/FLAC - 128mp3
128mp3/MVBR - FLAC
320mp3/HVBR - 320mp3
128mp3/MVBR - MVBR
LVBR               - LVBR
32mp3             - 32mp3
320mp3/HVBR - 320mp3
MVBR/128mpr - 128mp3

i was quite surprised at the results, especially when i mixed up FLAC for 128mp3 and 128mp3 for HVBR

test run on a Dell inspirion 1525, Hippo box amp and a Sennheiser HD558 modded,250band eq used

so it is actually quite difficuilt and almost impossible to differenciate 320mp3 and 128mp3