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Commandline Additions To Customize For My Hearing?, Help me out here!
mp3fan
post Nov 7 2002, 21:02
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Hello,

I have tested my hearing with frequency sweeps and have discovered my threshold is 17.3 KHz. I would like to customize LAME for my sensitivity. What command lines added to preset standard, outside of "--lowpass 17.5" could I use to lower the ATH set in LAME to lower the bitrate and have perfect sound FOR ME without wasting space?

I think that the ATH and sensitivty settings in LAME may be a tad too high and may be wasting bits on most material unnecessarily. What would the experts here recommend for an appropriate command line addition?

My goal is to shave off around 10 kb/sec average on my files and still get top quality for my hearing capabilities. I'm sure that a great majority of users would also benefit from this kind of commandline because from what my tests on others have revealed is that 17 KHz is also their limit on hearing as well.

My test subjects included three professional musicians (one of them being a former recording studio engineer), several people at my work (including several african-americans to include racial diversity), and my two brothers who live in town. Unfortunately, none of the people tested are younger than 23 years old. None of the subjects could identify frequencies beyond 17kHz including myself. This was using the frequency sweep test found at ff123's website.

mp3

This post has been edited by mp3fan: Nov 7 2002, 21:25
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Chun-Yu
post Nov 8 2002, 02:59
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LAME already lowpasses the input, depending on the bitrate you are using. It seems to automatically choose a "decent/suitable" lowpass frequency for the given bitrate/VBR quality level. For 128 kbps CBR, it lowpasses around 16 kHz. But I've found that I can clearly tell the difference between something lowpassed at 16 kHz and something that isn't, so if there's even a slight possibilty that anyone else will listen to your MP3s, I would stick with a lowpass frequency of 18 kHz or more. One song where it is VERY easy to tell the difference between a lowpassed and non-lowpassed version is Christina Aguilera's "Genie In A Bottle." This song has some somewhat strange noises (that were put there on purpose, because they only happen at certain points in the song) with EXTREME amounts of very high frequencies - 18 kHz+. In a spectrum analyzer, you can clearly see some high frequency peaks - sometimes around 14-15 kHz and sometimes 18 kHz+. On crappy speakers (and when encoded into 128 kbps MP3 using LAME's default settings), these noises completely disappear.
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mp3fan
post Nov 8 2002, 04:37
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I likely won't hear those 18 KHz sounds you speak of, nor will most other people I know or don't know for that matter. I just want to take the standard preset and maybe tune it down to my needs. Afterall, I'm the one who listens to my mp3s. Hopefully one of the gurus will come up with an answer soon. tongue.gif

mp3
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mp3fan
post Nov 8 2002, 23:51
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I can seriously hear the crickets chirping. Where is everyone around here? Is anyone able to respond? SOS! SOS!

mp3
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hans-jürgen
post Nov 9 2002, 11:14
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QUOTE (mp3fan @ Nov 8 2002 - 11:51 PM)
I can seriously hear the crickets chirping.  Where is everyone around here?  Is anyone able to respond?  SOS!  SOS!

Probably the "gurus" wonder if you've read this board the last few weeks... wink.gif All discussions about the new LAME versions, Dibroms own tunings, Gabriel's --alt-preset medium settings etc. deal with lower bitrates (with equal quality) than the usual aps files, as far as I remember. Furthermore Hydrogen Audio is not part of the Civil Service yet, if I'm not mistaken, so they don't have to be on duty 24 hours a day... ohmy.gif

The truth is that no one can fully answer your question for you, because it is your prefered music, your hardware, your ears, your brain, your mood, so you have to do it by yourself. And if you find out that it's too hard for you, then go for the lower quality and "don't worry, be happy".

For example I just did a quick test with LAME 3.92 and --alt-preset standard --lowpass 17.5 and found out that this command line worked (= the preset did not ignore my chosen lowpass setting). I also encoded the c't reference.wav with the usual aps setting and compared these three files for a while. I could not find any obvious differences between them, but I spent only about an hour on that. The only thing might be a tiny little bit of dirt in one sibilant that the --lowpass 17.5 setting showed in comparison to the original or the aps file.

So does this fully answer your question? Probably not, because you don't know with what kind of music I heard this one little artifact and if I will hear it again tomorrow or maybe tonight. And I don't know if you are a hardcore headbanger that likes to listen to screaming guitars and aggressive crash cymbals all the time, which might afford another setting or even another compression format. Get what I mean? wink.gif

By the way, the resulting bitrates were 169 kbps for the aps file and 164 kbps for the one with the added lowpass, so not the 10 kbps difference you're aiming at. But again, with other music this could probably come out like you expected. And choosing another format is probably not an option, if I consider your nick name. smile.gif


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mp3fan
post Nov 11 2002, 03:24
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Has anyone blind tested the addition of -V3 to the standard preset? What effect on the internal tweaks does this have? Can someone using -V3 still benefit from the minor adjustments in the setting?

mp3
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JohnV
post Nov 11 2002, 03:45
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QUOTE (mp3fan @ Nov 9 2002 - 12:51 AM)
I can seriously hear the crickets chirping.  Where is everyone around here?  Is anyone able to respond?  SOS!  SOS!  

mp3

Simple answer: If you go changing athaa or vbr-quality setting, there's no guarantee about the quality. Yes, I've tested -V3 and of course it lowers quality audibly. By changing athaa, you pretty much affect the sensitivity of the whole frequency range, so it's not ideal if you want to adjust according to your high freq hearing capability.

--lowpass is the only safe method here..

If you want to go lower bitrate, I suggest -Y rather than going for -V3. Yes, with -Y you lose some lower energy high freq content, but it might be the best option for you.

Anyway, for Lame 3.94 there will most probably be tweaked lower than APS mid-bitrate vbr-setting.


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mp3fan
post Nov 18 2002, 04:18
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Well, I don't want to use -Y because I can tell the difference between a 16KHz lowpass but not a 17.5KHz lowpass. Everyone of the people I ran my test on could hear out to 17KHz, but not 18 even. It seemed that 17KHz was everyone's usable limit. And with music material at 160 kb/sec, I can easily hear a 16KHz lowpass but cannot hear a difference at 17.5 lowpass. Is -Y different? Does -Y allow sounds over 16KHz but at a reduce sensitivity? If this isn't the case, I sure hope your preset medium does a 17.5KHz lowpass and not a 16KHz one.

mp3

This post has been edited by mp3fan: Nov 18 2002, 04:22
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SometimesWarrior
post Nov 18 2002, 10:55
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QUOTE (mp3fan @ Nov 17 2002 - 07:18 PM)
Does -Y allow sounds over 16KHz but at a reduce sensitivity?

Yes, if you look at the output of --aps -Y, there is still information over 16kHz, but it is usually present only with snare hits or sounds with lots of high frequency content (to contrast, the sound of a fuzzy-distorted guitar often has its high frequencies chopped at 16kHz with -Y because the high frequencies aren't very loud).

Try ABXing the -Y switch, since you might not be able to hear its effects, even though you can hear the effects of a 16kHz lowpass.
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Oge_user
post Nov 21 2002, 17:05
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I suggest you a lowpass of 18700.
The difference between 17500 and 18700 is audible: maybe now you can't hear any difference but is possible that in future or in other circumstances you can tell the difference.

For a VBR mp3 the filesize will not increase if you use 18700 instead of 17500 but the quality will be sure better.


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2Bdecided
post Nov 21 2002, 17:42
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QUOTE (Oge_user @ Nov 21 2002 - 04:05 PM)
The difference between 17500 and 18700 is audible: maybe now you can't hear any difference but is possible that in future or in other circumstances you can tell the difference.

I can't hear it!

I doubt my ears are going to magically improve over the years, and I've used exceptionally good equpiment to test what I can hear.

If no one else is going to hear your mp3s, there's no point in using a higher low-pass than you need - UNLESS your current audio equipment isn't very good, and you may upgrade later.

But then, if the bitrate isn't very important, you probably shouldn't be thinking about a lowpass at all.


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David.
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Oge_user
post Nov 21 2002, 18:19
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Even if the difference is not audible, since the mp3 will have (roughly) the same size there's nothing to loose if you use a higher lowpass. wink.gif


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SometimesWarrior
post Nov 22 2002, 00:34
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QUOTE (Oge_user @ Nov 21 2002 - 09:19 AM)
Even if the difference is not audible, since the mp3 will have (roughly) the same size there's nothing to loose if you use a higher lowpass.  wink.gif

If the filesize stays the same but there's more information being fed into the codec (higher lowpass), then the audio quality must suffer in some way because the same number of bits have to be allocated to a wider frequency range. The quality degradation is probably insignificant, especially since with VBR the bitrate will increase as necessary (unless it's already maxed out at 320kbps), but there's still no reason to increase quality past what is necessary for transparency.

I don't think anyone's physical hearing ability improves with age (this is my assumption, not a knowledgable statement). Perhaps one can get better at hearing artifacts or can notice more subtle nuances in music, but high-frequency hearing deteriorates with age.
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mithrandir
post Nov 22 2002, 02:59
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-Y is the only way to go because MP3 has no scalefactor for sfb21. Therefore, put data in that 16KHz+ region ONLY when absolutely necessary.

Remember that your upper threshold for a frequency sweep is different than that with regular music. When you play music, lower frequency signals (not necessarily bass) will mask the very high frequency ones.

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tangent
post Nov 22 2002, 05:04
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QUOTE (Oge_user @ Nov 22 2002 - 12:05 AM)
I suggest you a lowpass of 18700.
The difference between 17500 and 18700 is audible: maybe now you can't hear any difference but is possible that in future or in other circumstances you can tell the difference.

For a VBR mp3 the filesize will not increase if you use 18700 instead of 17500 but the quality will be sure better.

Whether the difference between 17500 and 18700 is audible depends on the listener's capabilities. And hearing depreciates with age, not improves, so if he can't hear frequencies above 17500 now, he probably won't be able for the rest of his live.

If you use VBR, there will definitely be a filesize increase going from 17500 to 18700. Quality increase depends on the user's able to perceive those high frequencies.
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mp3fan
post Nov 23 2002, 06:57
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Nobody I've tested so far can hear above the early 17KHz area. If the frequency passes beyond the early to mid 17KHz range, it quickly becomes inaudible for all that I've tested. Nobody managed to hear the high 17KHz let alone 18KHz range. That's from my own tests using several 20-something year old adults of various races, both genders, and technical backrounds in sound reproduction. I have not tested any teenagers yet because I don't know any. I'm sure younger aged people would be the ideal candidates to test for a true threshold for the average listener.

I'm of the opinion that there aren't going to be any real useable tones above 17KHz in music even for teenagers who MIGHT hear up to 18KHz. I'm also of the opinion if you can't hear up to 18KHz, having the extra frequency content won't add anything useful to your music enjoyment. I'm clearly in favor of a 17.5 KHz lowpass and a carefully tuned -Y option which only allows useable frequencies above 16KHz.

I believe that if the high frequency threshold of -Y is tuned properly and a lowpass of 17.5KHz is applied, then this will allow the proposed medium preset to achieve results on par with -alt-preset-standard for the VAST majority of listeners. I'm talking 98%+ of listeners! Of the estimated "possible" 2% remaining who could detect a difference using a 17.5KHz lowpass, they are not likely going to care because the frequencies above 17.5KHz are not likely going to be useful for music content. Also, due to masking properties, they aren't likely to detect the lowpass anyway on MOST material.

I believe this kind of thinking applied to a preset will allow VBR to finally reach the quality/bitrate results everyone has been waiting for in the mp3 format.

mp3

This post has been edited by mp3fan: Nov 23 2002, 07:15
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Oge_user
post Nov 23 2002, 13:02
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Ok, ok! ph34r.gif


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danbee
post Nov 26 2002, 12:44
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i seem to remember reading somewhere that even though those frequencies over 17-18k aren't actually audible, they do add a certain something to the music. just a though. if i can dig up an article i will post it.


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mp3fan
post Nov 28 2002, 19:06
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I recall an article regarding this but as I remember, it doesn't bear any scientific proof, only subjective rhetoric.

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This post has been edited by mp3fan: Nov 30 2002, 06:41
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