djuk

The theory behind this first bit is probably very obvious but I would just like to clear up my thinking on this!

Im assuming that when a CD is encoded to MP3 format, regardless of the bitrate you're instantly losing quality from that original recording?

If this is the case is there an alternative format to MP3 for encoding CDs to which will not lose quality?

I ask this because I have backed up quite a few of my CDs onto my Pc as MP3s and listen to the originals in the car. The sound quality does seem to be different, obviously its not going to sound identical because it is being played on 2 different devices but the MP3s do seem to suffer.


Cheers

David

Graz

There are some lossless compression algorithms about but invariably the file sizes are bigger.

Downloaded a file in Monkeys Lossless Audio Format the other day, have yet to listen to it but as they say on there web site, http://www.monkeysaudio.com/, it should be bit perfect.

Anyone else know of any lossless audio compressors?

Scooby96

What are you playing it on at home though? Could just be hardware differences unless your an audiophile???

Hmmmn arcam vs radioshack

Dracoro

Lot's of people comment on the quality of mp3 vs CD etc. My take is this.

In a car, walkman, hdd player etc. with headphones, there's no real difference unless you are actually looking for them (what's the point of that eh?!)

I have a decent 'audiophile' stereo (arcam cd/amp, quad speakers) and I CAN hear the difference between mp3's and CD. However on my older Kenwood stereo (separates), the difference is hard to ascertain. MOST people won't have a stereo much better than the Kenwood setup I have (indeed, most people will have midi/mico/car systems to listen with).

Bascially what I'm trying to say is, unless you've got a good separates sound system, then you're not gonna really tell much difference. Those that can are probably actively trying to hear differences rather than just sitting back and enjoying the music.

BTW - all the above is assuming you record mp3 at 128 or above. 128 is a good balance of quality and space, 192+ is better but take more room on your HDD, any less than 128 will sound crap. You can what up the bitrate to 320+ and that will sound every bit as good as mp3 no matter how good the stereo or ears.

DazV

ogg vorbis format offers better compression / quality

see www.vorbis.com for more info

Freak

vinyl

(yes im a vinyl junkie)
No sample rate or bit rate restrictions, but not quite as practical as i think you were hoping for

The thing is, mp3 is a compromise between lossy compression, file size and quality- you can rip them as a wav, but it takes up loadsa space.

Try listening to an Mp3 over a club system then saying there is no difference- its very noticable, especially in the bass.

hedgehog

Assuming that what you mean is you are encoding the CDs to MP3 format then the best quality option is to just make a direct 16 bit 44.1kHz copy of the digital audio as a WAV file. The disadvantage is that this file is about 10 times as large as a 128 bps mp3. With modern huge hard disks and many modern portable players playing WAV files this may not be a problem for you and is certainly worth considering.

In general audio, even exactly the same audio, will tend to sound different on differing systems so it is possible that what you are hearing is not a problem with the MP3 encoding but literally just the differences between the systems. In saying that there are some things that I have found MP3 encoders and decoders can struggle with and there are also differences between different brands of MP3 encoders and decoders.

Oh, what sort of hard disk are you using in your pc?? I ask because some nutter in the US has come out with the claim that he can hear quality differences between different brands of hard disk! I suspect he is priming the market for the arrivial of his very expensive audiophile disk drive. Maybe you need one of those new audiophile hard disk drives? :-)

AndyC_772

iTrader: (2)

Possible if and only if he's talking about the mechanical noise it's making in the background. It is not technically possible for an MP3 or WAV file recorded on one brand of disc to sound any different to any other - fact.

The right way to determine the effect of a compression scheme such as MP3 is to convert back to a WAV file and burn a CD - then pop that CD in the same player as you use to listen to the original. Rest assured, on a decent system you can hear the difference very easily.

As Dracoro says, MP3 has never been a high quality format, it's always been merely 'good enough' to use on headphones, or in the car, or on any other equipment where sound quality is taking a back seat.

ALi-B

iTrader: (1)

Also I find with MP3 it's very dependent on the software used to rip it off the original CD.

I found some apply a 20KHz low pass filter, which is not good for your top end sounds, they may employ a 50Hz high pass to get rid of hum - not good for your sub bass. Then there is the way it's encoded, error checking and correction etc. I'm not 100% sure of the ins and outs, but all I can say is one program can sound far better than another.

Then there is whats used to play it back. It's down to the software to convert it back to a pure analogue signal and employ correction (like a cd player, one can sound crap where another sounds good). Think of it as playing back music on your computer through a sound card (wave), it always been known that computer soundcards are very poor interms of sound quality due to poor quality components, at one time some even used 741 Op-amps as the final output driver - in English the most basic form of output driver you can get off the shelf, which has all the problems of switching distortion and non-linerarity that transistor amplifiers had back in the 60's and 70's.

So, blaming MP3 as the format soley responsible for the lacking of quailty is unfair. My friend reckons that WMA (windows media) format is better, I can't really tell TBH. But I find a bit rate 192 is the minimum for what I'd say acceptable on a home system. With cars you can always get away with lower as the road noise whilst driving removes alot of the detail.

hedgehog

Nope, not the mechanical noise. This bloke can hear the difference in the quality of the same audio files stored on different makes of hard disk.

I mean, what gives with these people? Why doesn't it come as a shock to him when he gets up every morning and his wordprocessor documents contain exactly the same words no matter who makes the disks they are stored on?

However, I agree, MP3 is a fun, portable, handy format and people should have fun with it, listen to more music, get broader musical interests and work hard to hear everything before they die. Now, personally I prefer MP3 players with IBM disk drives, you get much better definition in the bass and the treble has a warmer quality to it almost like analogue...

You have to laugh.

logiclee

It depends on what quality of equipment you are using to listen to your music.

So called lossless formats are Mathematically Lossless but copying process does seem to loose quality.
On a medium to high end system you can hear the difference between a lossless copy and the original.
Even the pro's seem to struggle, tracks on Albums like "Now 87" and "Hits 67" are usually quite a lot poorer in quality over the same track on the Artists own Album.

As for those that say 128k mp3 is CD quality....... in your dreams IMO.

Cheers
Lee

Edited to add......
I do use MP3 in the car and for background music at parties etc. Every format has it's uses.

ALi-B

iTrader: (1)

Well you can already buy CD-R's "For Audio" Can someone tell whats the difference between an Audio CD-R and a data CD-R with the same CD audio recorded onto them?

hedgehog

I've the same problem all the time. Everytime I copy over a Word document it ends up saying something totally different to when I typed it the first time, I really didn't type that stuff about my boss' mother for example. Only the other day I copied over a photograph of my dog and when I next looked at it there was a picture of a castle in germany. I guess we need some audiophile quality disk drive cables to stop this happening.

Gold IDE cables anyone? Only £500 each.

AndyC_772

iTrader: (2)

A couple of explanations:

- tracks on such albums tend to be of very low quality to begin with

- who says that there isn't some processing carried out on the music before it's recorded? The version on the compilation could be equalised to be the same volume as other tracks on the compilation, for example, rather than the same volume as on the original CD. Or, it could be companded to sound 'better' (and I use the term loosely) on a cheap stereo. The easy way to tell is to rip both tracks to a PC and do a binary comparison.

AndyC_772

iTrader: (2)

It's certainly true that different discs will put different electrical noise patterns onto the power supply in the PC, but to draw the conclusion that he can hear a difference between music stored on different brands of disc is ludicrous. A PC is not a hi-fi component - its power supply, motherboard, sound card and so on will all have an equal or greater effect on what can only be a compromised sound. Golden Ears might just as well hold an opinion on network cards or cooling fans.

Feed the music out of the PC through an optical cable (to provide electrical isolation and stop noise getting out) into an offboard DAC and then tell me there's a difference between brands of hard disc...

logiclee

Yes Andy I have heard of this, they dynamically compress the sound so it sounds better on setups that struggle to produce the full dynamic range.
Most analogue radio stations do the same to their broadcasts, including Radio1.

Every one can have a laugh about copies and orignals only being 1' and 0's but the difference in sound quality is real. It may be due to the CDR introducing more errors when being read by the laser, I don't know.
The difference is very audible on £300+ CD players when coupled witha decent amp and speakers though.

Lee

angrynorth

Dependant on what your players supports there is

Apple Lossless Encoder (works with itunes, quicktime, iPod, etc)
Windows Lossless Encoder (Not a scooby what it works with and not too bothered either )

hedgehog

There might be something in what you say Lee if you are talking about copies of CDs, rather than just copying audio files about on hard disks. It may be that you are hearing the effects of error correction. Correcting an error is totally different from hiding it and produces a result that is exactly the same as the "un-broken" version.

Also, some CD players are none too well designed and the extra load of their error correction circuits having to work hard can seriously impact upon the PSUs and the like, resulting in degredation of sound quality.

So, I can see a simple and logical reason why a copy of a CD might sound different to the original, it might just be making the error correction on the CD work less hard for example.

There are also people who claim to be able to hear the difference between audio edited, or burned, using different (pro tools, cool edit etc.) editing packages. This has been tested and a file compare done between the CDs. They were the same in every single bit and yet some people said there was a difference in what they were hearing. Snake oil methinks, but the foundation for a "hi-fi" market based around PC audio.

Why do people make up imaginary audio problems when, as AndyC points out, there are simple engineering reasons for real problems that can be solved at little cost and with a bit of good design?

AndyC_772

iTrader: (2)

It IS just ones and zeros! There's no in-between... moreover, the 16-bit samples are encoded, interleaved with each other and spread around the disc - what goes to the DAC is not in any sense the signal from the laser, it's the output from a purely digital ASIC that's done the decoding.

If there's a difference in sound quality then it's down to bit errors when the disc is read (unless reading a CD-R somehow puts more noise on the power supply, which I doubt). Get too many bit errors and the glitch has to be concealed by interpolation, which may be audible. Even so, a clean, well-burned disc shouldn't have any such errors. (A cheap one burned at 48X could be a different story, mind...)

AndyC_772

iTrader: (2)

LOL That's even worse than the gold-plated-mains-plug brigade! At least that has some possible basis in science - albeit a less significant one than whether the cat sitting on the sofa in the listening room has long hair or short hair...

Echo

I used to laugh at the gold plated mains plug brigade but in my studio when the power had gone down and was not going to be fixed for a week we had to get a generator in. The difference on the sound was simply breathtaking. Even the TV had a better picture! Good mains/power makes such a difference.



Mike

AndyC_772

iTrader: (2)

That may well be - you're isolated from all the rubbish that your neighbours are puttingn on the supply, so it doesn't surprise me that having your own generator makes a difference.

Gold plating mains plugs, however, does NOT have the same effect...

what would scooby do

I use WMA on it's highest quality settings, and only use compressed material in the car where absolute sound quality is pointless due to road noise etc.

At home I listen to a lot of DVD Audio stuff, and to be honest when you listen to CD afterwards, the CD's sound very shoddy

ALi-B

iTrader: (1)

A/C single phase Mains really is the worst power source for audio you can have. Everytime it drops(or rises) towards zero volts on every half wave you have to rely on the capacitors in the power supply of the amp to supply the current and maintain the voltage. Under load the output from the power supply will "ripple", and will affect the performance of the amp.

Then add to that how dirty mains power is, it's any wonder anything actually works. UK mains is rated at 240v RMS, (if my electronic theory serves me well) the peak volts can be up to 600v!

Gold plugs won't make any difference. Cut off the power to everones houses from the local substation and you may have an improvement. I used to laugh at my mates house - his dad has a big shed with a huge table saw and lathe. You could be sitting in the lounge and all the lights would dim for a few seconds everytime he switched on the saw! Think of how that would affect an audio system!

logiclee

Household mains supply is crap. It depends how lucky you are as to how crap it is.

At work we run an 11kV 4000hp motor and it starts, runs through its cycle, stops then reverses direction 53 times an hour.

We have loads of problems with people complaining of electrical interference in the local Village even though we have a Static Compensator that cost millions to install.

Gold plugs will do nothing on a houshold mains supply. You just need a good connection and overrated cable.

A guy at work does copied CD's, He has a hard drive full of albums some of them encoded at 48k, I've listened to a couple and they are absolute ****e I can't believe anyone pays for this rubbish. Even sounded crap in the car.

You may be right Andy, I said I had no idea why. It's not snake oil either, even my Wife can tell the difference and she has as much interest in the subject as I do about Eastenders.
I even tried a demo of an audio CD copier and that was the same. With the quality of the kit I tried it with it has to be the quality of the CDR's not the equipment.

Cheers
Lee

Dracoro

At 48k I'm not surprised!!!!!!!!

logiclee

Yeh but people still buy them.

Car Boot sales and Sunday market traders sell heaps and I bet most are low quality rips burned at 48X.

Lee