This all started out as wanting to try some modifications to a budget CD player. The first step was to replace the opamps and the standard fitment was a bjt device that never found favour with audiophiles despite being designed as an audio specific part. In fact the late JLH wrote at the time this device was possibly the finest of all opamps available......
I fitted LM4562's which are on the money characteristic wise compared to the originals. I'm just mentioning all that for completeness as the following modifications under scrutiny were in the digital domain. I thought it would be fun to document all this and even try and capture some files that could be used for listening purposes.
What the test entails...
This is to try and gauge listener comments between two files played on a budget CD player. Adding a poll seemed a fun idea too.
As mentioned above, the hardware (the player) has had some modifications carried out that affect only the digital processing side of the player. I'm not going to say any more than that at this stage.
How the voting, the files and the poll work.
To give you all some choice in musical content there are three folders you can choose from. You can listen to any and vote, or if you get interested then vote on all or any of them.
Folder ONE contains a large scale orchestral work by Rachmaninov. You vote on track A or track B as being your preferred choice.
Folder TWO contains an old Patsy Cline number. You vote on track C or track D as being your preferred choice.
Folder THREE contains a jazz vocal track. You vote on track E or track F as being your preferred choice.
There is also an 'I have no preference' option for those that are happy with either.
So vote on as many of the folders as you listen too.
Comments posted in the thread are welcome. Any observations of the perceived musicality of one vs another would be great.
After the test and poll have run their course I will upload further non music (test) tracks that might reveal more differences together with a small table of data perhaps giving clues to linearity and resolution.
So here are the folders on Dropbox.
ONE
TWO
THREE
I fitted LM4562's which are on the money characteristic wise compared to the originals. I'm just mentioning all that for completeness as the following modifications under scrutiny were in the digital domain. I thought it would be fun to document all this and even try and capture some files that could be used for listening purposes.
What the test entails...
This is to try and gauge listener comments between two files played on a budget CD player. Adding a poll seemed a fun idea too.
As mentioned above, the hardware (the player) has had some modifications carried out that affect only the digital processing side of the player. I'm not going to say any more than that at this stage.
How the voting, the files and the poll work.
To give you all some choice in musical content there are three folders you can choose from. You can listen to any and vote, or if you get interested then vote on all or any of them.
Folder ONE contains a large scale orchestral work by Rachmaninov. You vote on track A or track B as being your preferred choice.
Folder TWO contains an old Patsy Cline number. You vote on track C or track D as being your preferred choice.
Folder THREE contains a jazz vocal track. You vote on track E or track F as being your preferred choice.
There is also an 'I have no preference' option for those that are happy with either.
So vote on as many of the folders as you listen too.
Comments posted in the thread are welcome. Any observations of the perceived musicality of one vs another would be great.
After the test and poll have run their course I will upload further non music (test) tracks that might reveal more differences together with a small table of data perhaps giving clues to linearity and resolution.
So here are the folders on Dropbox.
ONE
TWO
THREE
Karl, just to let you know I'm onto it, 
. A bit stale at the moment, so I'm not going to vote or comment for a bit, need a change of pace probably for a time - anyway, had a quick listen to the Patsy Cline, one obviously superior to the other - so something's happening!
Will get back later ...
. A bit stale at the moment, so I'm not going to vote or comment for a bit, need a change of pace probably for a time - anyway, had a quick listen to the Patsy Cline, one obviously superior to the other - so something's happening!Will get back later ...
Test
On a Mac with some small Cambridge Audio powered speakers, I preferred B, D, and F.
On a Mac with some small Cambridge Audio powered speakers, I preferred B, D, and F.
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Most obvious is I like C much better than D.
I like B better than A in the piano dynamics.
Hardest is to choose between E and F but at last I choose F.
In general I prefer a "sharper" sound which is more obvious with C and B but less with F.
So BCF for me, using Logitech computer speaker at work.
I like B better than A in the piano dynamics.
Hardest is to choose between E and F but at last I choose F.
In general I prefer a "sharper" sound which is more obvious with C and B but less with F.
So BCF for me, using Logitech computer speaker at work.
This is great. One of you three has voted consistently in all three groups but ultimately which is it that you all preferred ?
Hopefully we might get some more joining in.
(And if any of you are doing file analysis on these then go ahead and say what you find/don't find. Lets try and tie up the subjective result with what has actually occured)
but ultimately which is it that you all preferred ?Hopefully we might get some more joining in.
(And if any of you are doing file analysis on these then go ahead and say what you find/don't find. Lets try and tie up the subjective result with what has actually occured)
I think it is already clear which one is most preferred? BDE, BCE, BCF, so the file associated with B is the most preferred one.
I found the difference is, from certain POV, similar to the 2nd harmonic test. The original is sharper than the "rounded" one. But in the 2nd harmonic test, the distortion seems to add musicality, here the less preferred one strips off musicality.
Long time not working with CD player, I can't imagine what kind of modification is possible. If this were reclocking to remove jitter, it would be great. But I don't believe a jitter will have such a big effect as this.
So what else? Aren't most other things already taken care of by ICs? Changing Crystal clock? Oversampling? From sound differences, most possible modification is related to oversampling option, tho not easy to setup.
You'll have to wait and see, but yes interesting thoughts and comments.
Remember this is very much a budget player (real bottom of the market job at the time it was popular) and so we are not comparing state of the art with 'something else'. This is just a simple listening test that hopefully brings a little of the modification across in the files presented.
Remember this is very much a budget player (real bottom of the market job at the time it was popular) and so we are not comparing state of the art with 'something else'. This is just a simple listening test that hopefully brings a little of the modification across in the files presented.
I can hear no significant difference between the track pairs, but this is through the system attached to my computer. It consists of an "on-board" Realtek sound card, NAD 7120, and an old pair of Warfedale Bookshelf speakers. Perhaps I might notice a difference on my "main system", but have no way to "get it there".
I do feel however, that playing a "good quality" CD in same computer's drive results in better quality audio, than the provided samples.
I do feel however, that playing a "good quality" CD in same computer's drive results in better quality audio, than the provided samples.
Well I was hoping we might have picked up more listeners for this but no matter
So a bit more on this... when I modded the player (before the mod and after) I also made two small files of a musical track, one is at -40db and the other at -60db. These are from a test disc and have been recorded at these levels originally.
So here are two folders, one corresponds to the unmodded player and one the modded. Each contains the -40db and -60 db tracks. The levels have been normalised back to normal SO DO NOT turn up the volume when playing these.
These have obvious differences in the quality of the audio. It will be interseting to see whcih of these 'low detail resolution' files you prefer and then see whether that tallies with your preferred choice of the main files.
So two folders. Group A and Group B. One is the modded player, one the standard.
GROUP A
GROUP B
So a bit more on this... when I modded the player (before the mod and after) I also made two small files of a musical track, one is at -40db and the other at -60db. These are from a test disc and have been recorded at these levels originally.
So here are two folders, one corresponds to the unmodded player and one the modded. Each contains the -40db and -60 db tracks. The levels have been normalised back to normal SO DO NOT turn up the volume when playing these.
These have obvious differences in the quality of the audio. It will be interseting to see whcih of these 'low detail resolution' files you prefer and then see whether that tallies with your preferred choice of the main files.
So two folders. Group A and Group B. One is the modded player, one the standard.
GROUP A
GROUP B
As ever, thanks for trying them Pavel. The main files are at the top in the first post.
I would say to try and listen beyond the noise and hash in these low level files if possible because the audio does sound very different one to another. If you listen to the quieter parts you can easily pick out the 'chirps'. Did you compare one to the other and notice that the hash or chirp is at a significantly different pitch in one file compared to the other. The modifications have caused that.
These low level tracks sound anything but clean even without putting them through an A/D convertor to produce WAV files. In other words, listening to them direct from the player into a headphone amp and with good h/phones. So they will never sound clean, that is how CD players play this proper test disc. CD has often been critised for worsening performance as levels fall away. That is what much of this is that you are hearing. The thing is, the modded player vs the unmodded are very different.
Are the modifications successful or not ? (is the question)
(And remember that this is very much a budget player, in fact its around 30 yrs old)
I'll post more info, probably tomorrow to wrap all this up.
I would say to try and listen beyond the noise and hash in these low level files if possible because the audio does sound very different one to another. If you listen to the quieter parts you can easily pick out the 'chirps'. Did you compare one to the other and notice that the hash or chirp is at a significantly different pitch in one file compared to the other. The modifications have caused that.
These low level tracks sound anything but clean even without putting them through an A/D convertor to produce WAV files. In other words, listening to them direct from the player into a headphone amp and with good h/phones. So they will never sound clean, that is how CD players play this proper test disc. CD has often been critised for worsening performance as levels fall away. That is what much of this is that you are hearing. The thing is, the modded player vs the unmodded are very different.
Are the modifications successful or not ? (is the question)
(And remember that this is very much a budget player, in fact its around 30 yrs old)
I'll post more info, probably tomorrow to wrap all this up.
The -60dB files had too much noise (maybe B was better), but I preferred the -40dB file in group B.
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