Test CD for measurements of CD Players

[Deleted member 77012]

To me, even statements that should be very simple to understand are quite confusing:

"C_Sine_999.91Hz_0dB_-1dB_-3dB_-6dB_NoDither_L.wav" is 4 minutes long, divided into 4 sequences of 30sec each of the same test tone played at 0dBFS, -1dBFS, -3dBFS and -6dBFS.

So those four 30-secs sections of tone are separated by three 40-secs gaps, to sum up to a total length of four minutes?

 

[Watire]

@NTTY ! You're a hero !

 

[Multicore]

Now it would be awesome if someone could do something similar for a test ISO file that we can download and burn to an LP for TT, arm and cart setup and debugging.

 

[NTTY]

Now it would be awesome if someone could do something similar to for a test ISO file that we can download and burn to an LP for TT, arm and cart setup and debugging.

I thought so many times about it! I know a company in my country that can create an LP based on whatever files we give them. It's not cheap, but we could certainly create a test LP. I suppose someone else will find time before me, though.

 

[DrZingo]

To me, even statements that should be very simple to understand are quite confusing:



So those four 30-secs sections of tone are separated by three 40-secs gaps, to sum up to a total length of four minutes?

Maybe it's left and right? That would make eight tones.

 

[tpd]

To me, even statements that should be very simple to understand are quite confusing:



So those four 30-secs sections of tone are separated by three 40-secs gaps, to sum up to a total length of four minutes?

The file is actually only 2 minutes. Opening the file in an editor like Audacity shows the contents as just four 30-second tones.

 

[Deleted member 77012]

The file is actually only 2 minutes.

Uhm – that doesn’t match the OP’s statement at all ...

How can I download that file to check for myself? Don’t see any link, sorry.

 

[NTTY]

The file is actually only 2 minutes. Opening the file in an editor like Audacity shows the contents as just four 30-second tones.

View attachment 402288

Indeed 2min long. I initially made them 4 min, 1min each, but it was unnecessary long when I first used them. So I updated the files to make them shorter. And as you show, I also subsequently added fade in/out between each test tone, and on recommendation from @restorer-john, to prevent artificial situation like an impulse.

 

[carsknivesbeer]

Thanks you for this writeup. After looking at the tests of CD player and seeing they are not the same (audible or not) it is great to have a DIY way to do it. This format is my preferred way of listening and being able to experiment within a budget is great.

Do you have any thoughts on test CDs like the Denon Audio Technical one for testing outside the scope of the testing in the post?

 

[carsknivesbeer]

Now it would be awesome if someone could do something similar for a test ISO file that we can download and burn to an LP for TT, arm and cart setup and debugging.

Genuine question: are the ones on the market like the Otofon ones not good enough?

 

[Multicore]

Genuine question: are the ones on the market like the Otofon ones not good enough?

Idk. I just try to make jokes.

 

[NTTY]

Do you have any thoughts on test CDs like the Denon Audio Technical one for testing outside the scope of the testing in the post?

I used a lot the Denon CD audio Check as it was the first one I had. But since it was not including all files I wanted and only undithered test signals, I wanted more. So my first objective was to verify if I could burn a CD of the same quality. Once there, I started creating my own test CD.
I think the CBS CD-1 is a nice test CD and the Sony YEDS-18 is the reference mentioned in a number of service manuals I’ve read.
But I don’t think this replies to your question.

 

[Deleted member 77012]

Indeed 2min long.

I see.

I’m glad you modified your original statement accordingly.

 

[restorer-john]

I used a lot the Denon CD audio Check as it was the first one I had. But since it was not including all files I wanted and only undithered test signals, I wanted more. So my first objective was to verify if I could burn a CD of the same quality. Once there, I started creating my own test CD.
I think the CBS CD-1 is a nice test CD and the Sony YEDS-18 is the reference mentioned in a number of service manuals I’ve read.
But I don’t think this replies to your question.

The Denon is an excellent test CD with 99 tracks and is easy to find, but it has no dithered tracks as you mentioned.
The CBS CD-1 is also a fabulous test CD, and is a standard for testing, contains some additional signals that make it rather unique. It pops up occasionally and I recommend anyone with a serious interest in CD players getting hold of one. It can be duplicated, but you could run into the issues below.

The Sony YEDs and the Philips test set, along with the Pierre Verany test set offer precision optical characteristics and calibrated errors etc which cannot be duplicated. They are also hard to find and expensive. But they are worth it to own, as down the track, there will be no way to accurately set up, repair and characterize players without them.

 

[DanielT]

It would be interesting to see how good, or bad, some of the earliest and cheapest CD players were. CD players that are around four decades old. Such CD players that were then used as comparative examples to show that good record players sounded better. As far as I remember, there were only subjective judgments regarding those comparisons. But how do such old CD players actually measure up?

Anyone have any of these old ones lying around in some storage room?
It might be possible to find one at a flea market for a few $? Just to then test performance, check how they measure.

 

[DanielT]

Still don't understand how loop calibration can improve my data as I don't know how much error is DAC related and how much is ADC. Anyway I've done it.
i.e. my cheap Hitachi portable CD player with one of your favorite test:
View attachment 402062
View attachment 402063

You say : ..cheap Hitachi portable CD player .. What model? How old is it?

Maybe your Hitachi is one that I was wondering if anyone had in the post above?

 

[AnalogSteph]

You say : ..cheap Hitachi portable CD player .. What model? How old is it?

DAP-XP2E, as one can clearly read. 2000ish, "shockproof", made in China. Run of the mill cheap PCDP, by no means early.

It would be interesting to see how good, or bad, some of the earliest and cheapest CD players were. CD players that are around four decades old.

@NTTY has already measured a Marantz CD-73, which is pretty much a first-gen unit (SAA7030 + 2x TDA1540, CDM0). Not basic enough, I guess?

 

[NTTY]

It would be interesting to see how good, or bad, some of the earliest and cheapest CD players were. CD players that are around four decades old. Such CD players that were then used as comparative examples to show that good record players sounded better. As far as I remember, there were only subjective judgments regarding those comparisons. But how do such old CD players actually measure up?

Anyone have any of these old ones lying around in some storage room?

Few that I reviewed (or planned to) of good value vs "SOTA" CD Players of respective period:

1982+ : Marantz CD-73 vs Yamaha CD-1 (to come, being serviced)
1990+ : JVC XL-Z335 vs Denon DCD-3560
2000+ : Yamaha CDX-393 vs Orpheus Zero

I have others to review from the 80s, couple of Revox and an interesting Sony with a Philips DAC running in staggered mode.

Note that most of the early CD players I own needed a refresh (power supply, belt, laser, display, ...).

 

[NTTY]

@NTTY has already measured a Marantz CD-73, which is pretty much a first-gen unit (SAA7030 + 2x TDA1540, CDM0). Not basic enough, I guess?

The first iteration were all expensive and reusing Philips and/or Sony designs. But Yamaha managed to release the CD-1 at twice the price that of the Marantz CD-73, make the latter relatively cheap

 

[DanielT]

DAP-XP2E, as one can clearly read. 2000ish, "shockproof", made in China. Run of the mill cheap PCDP, by no means early.


@NTTY has already measured a Marantz CD-73, which is pretty much a first-gen unit (SAA7030 + 2x TDA1540, CDM0). Not basic enough, I guess?

Aha, DAP-XP2E. Sorry I missed it.