Old question, wrong answer

compact disc, dacs, mp3 players and streaming audio
muskrat1954
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Old question, wrong answer

Post by muskrat1954 » 24 Apr 2018 06:14

I ran across this reading thru posts on this forum, about halfway thru "why is my stereo louder when I switch from tt to CD?" While cart output varies the real reason is that the CD standard is double the previous standard, 500mv. Remember, louder is better! There was concern that CD players would overload aux inputs on some stereos.

]eep
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Re: Old question, wrong answer

Post by ]eep » 25 Apr 2018 04:46

This is true. One of the sly tricks of marketing, pushing digital.
I remember I went to the biggest hifi show in my country. I went to the Philips stand to listen to the then new DCC. You could listen to CD vs DCC. I came prepared and brought my own headphones (Sony MDR-92 top of the line on ear). I could clearly hear the CD output was tampered with! With what I learned much later, it sounded like there was a mediocre sounding elco inserted after the output stage to make it sound worse. It did not sound like other players on display. The DCC did. Clearly a dirty trick.

All in all, CD-players, or better DAC's, are nowadays all mass produced sigma delta designs that are low V output that need an I/V stage. So the output of most digital gear is determined by dual opamp(s), easy to tailor. But not adjustable by the typical user!

Analog is very different. There are many variables. Different coil/magnet systems, number of windings, magnet strength on the cartridge side. Different phono amps, input variables, amplification levels. All consumers choices.

If you want to complain about to much choice? Go ahead. That's the price of freedom. You need to think. But please don't complain your freedom cost too much effort.

DeepEnd
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Re: Old question, wrong answer

Post by DeepEnd » 25 Apr 2018 17:18

I seem to remember that the formal specification for (an unbalanced output) from a CD player was supposed to be 2.0V (RMS) compared to a typical line input sensitivity at 200mV for full output (I think DIN spec output was 300mV).

In effect the signal level can be 10 times what is needed for full output (although these days 1V (RMS) from chips driven from a 3.3V power rail rather the 2V from 5 V power rail is more likely). Signal is 5x to 10x more than needed.

Compare this to phono stage at say 5mV cartridge output vs 3mV sensitivity signal is only 1.67 times what is needed. As a result the amp normally needs CD turned down compared to vinyl.

]eep
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Re: Old question, wrong answer

Post by ]eep » 26 Apr 2018 04:50

To be honest, output volume is all over the place. When watching TV, especially satellite, volume differs greatly. Depending on codec some are hardly intelligible and some are dynamically squashed to maximum loudness.

This has nothing to do with technical issues but everything with marketing (loudness war) and plain lazyness.

aardvarkash10
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Re: Old question, wrong answer

Post by aardvarkash10 » 26 Apr 2018 07:03

DeepEnd wrote:I seem to remember that the formal specification for (an unbalanced output) from a CD player was supposed to be 2.0V (RMS) compared to a typical line input sensitivity at 200mV for full output (I think DIN spec output was 300mV).

In effect the signal level can be 10 times what is needed for full output (although these days 1V (RMS) from chips driven from a 3.3V power rail rather the 2V from 5 V power rail is more likely). Signal is 5x to 10x more than needed.

Compare this to phono stage at say 5mV cartridge output vs 3mV sensitivity signal is only 1.67 times what is needed. As a result the amp normally needs CD turned down compared to vinyl.
Kinda, but no.

https://en.wikipedia.org/wiki/Line_level

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Re: Old question, wrong answer

Post by aardvarkash10 » 26 Apr 2018 07:39

CD (or in fact any digital input) will tend to sound "louder". It does this, in part, because it IS louder, and in part because of historical non-standards.

Phono input had no real one standard, but in fact a string of different nominal values associated with different manufacturers (who set their own recording level and frequency compensdation standards), and different cartridge types (crystal, MM, MC). This leaves aside differing recording and cutting standards for the vinyl itself.

Once the phono signal was inside an amplifier, it was anyone's guess. After frequency compensation, the phono section might have amplified the signal anywhere between +32db to +44db, before passing the signal on to the power amp section.

Generally though, vinyl at least had a wide dynamic range. It has too - it lacks the abilty to provide sustained, highly compressed loudness that digital media has. So its loud bits are kinda loud, but not really loud because that would literally throw the stylus out of the track.

Digital doesn't have that weakness (or strength depending on your pov) and because it has been optimised to perform in loud acoustically poor enviroments ie your car, and memory (and hence dynamic range) was historically expensive, audio in a digital format is dynamically narrow in range and subjectively louder - sometimes offensively so.

But at least we now have a standard (albeit regularly overlooked) for line level.

muskrat1954
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Re: Old question, wrong answer

Post by muskrat1954 » 29 Apr 2018 18:56

I remember many articles touting the dynamic range of digital. Sadly, it has not been used much in popular music. Even most cheap headphones sound better than cheap plastic speakers. I thought this would lead to more interest in good sound. Wrong again!

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Re: Old question, wrong answer

Post by pilotpete2 » 02 May 2018 01:06

"Digital doesn't have that weakness (or strength depending on your pov) and because it has been optimised to perform in loud acoustically poor enviroments ie your car, and memory (and hence dynamic range) was historically expensive, audio in a digital format is dynamically narrow in range and subjectively louder - sometimes offensively so."

This is not anything to do with the CD format, or digital recording in general, rather it has everything to do with "artistic" decisions made by producers and "artists" that feel the need to be louder than the next guy.
To add more compression to a classic rock album from the 60's or 70's when mastering a CD of the album is a crime against humanity in my book!

Take the time to listen to a good jazz or classical recording on CD of strictly acoustic instruments, where no dynamic compression has been used....whole nuther experience.;-)

hoolio
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Re: Old question, wrong answer

Post by hoolio » 08 Jun 2018 09:15

CD represents too much gain to your amplifier and that's why Rothwell Audio came up with a 10db in line attenuator. If you place the attenuators at the input of a power amp then you will also gain 10db of head room.
Read it here: http://www.rothwellaudioproducts.co.uk/ ... ators.html

I've used these for years, highly recommended for CD replay.

Phono-lover
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Re: Old question, wrong answer

Post by Phono-lover » 13 Jun 2018 18:50

I understand that if a CD player has an unusually high output voltage it will cause distortion and the need to attenuate may be needed. 10DB seems excessive.

OK I Read it here: http://www.rothwellaudioproducts.co.uk/ ... ators.html

And what kind of logic is this?

"If you operate the system with the volume control turned down around the nine o'clock position most of the time, the signal to noise ratio will be much worse than the manufacturer's spec. Operating the volume control further up its range will improve the signal/noise ratio, but the actual volume of the music may be just too loud. However, if the signal is reduced by 10dB with a pair of attenuators at the inputs to the power amp, then the volume of the music will be reduced, but the volume of any noise generated by the pre-amp's gain stage will be reduced too. This allows you to operate the pre-amp's volume control farther round its range and the signal to noise ratio will be improved by 10dB"

This implies that an amplifier has poorer signal to noise ratio when the input is higher. It will amplify more pre-amp noise when the volume control is turned down but less when it is turned up so we need to input less signal.

As soon as I turn it up to achieve the original loudness that "pre-amp noise" will be amplified as before and not be less. I think it will be worse because the signal is lower now and the unchanged noise floor (hiss and hum) is now being amplified along with the signal.

Did I read this wrong or is it nonsense.

Spinner45
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Re: Old question, wrong answer

Post by Spinner45 » 13 Jun 2018 20:26

Signal to noise translates to the recorded sound vs. the noise floor level of the equipment used.
Naturally, pumping a bigger signal into a noisy amp will sound better, to a point.
Over-doing it can lead to distortion once the headroom is maxed out.

hoolio
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Re: Old question, wrong answer

Post by hoolio » 14 Jun 2018 08:46

Rothwell aren't the only one that sells attenuators.

The pro audio crowd have used these to drop say the output of a microphone into a pre amp, have look at these

https://www.google.com.au/search?q=in+l ... 66&bih=700

http://www.uneeda-audio.com/pads/

Scroll down and you will see a diagram https://groupdiy.com/index.php?topic=37738.0

I'm not tech savy but I have made my own attenuators. Along with the Rothwell I have Harrison attenuators too in 2,3 and 6db attenuation.

The out put of a CD player is too high. As Rothwell says you're not getting much use out of the volume control. Imagine using a 12 o'clock setting with ease. The benefit is not better sound quality it's more of a saner way to enjoy your music. It's non fatiguing and for sound stage lovers you get less congestion. Thats it, I'm not a reviewer. :lol: One last thing. If you have a separate pre and power amp then plug the attenuator into the input and plug your interconnect into that, this helps things like the sound stage.

cafe_liegeois
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Re: Old question, wrong answer

Post by cafe_liegeois » 14 Jun 2018 10:30

hoolio wrote:If you have a separate pre and power amp then plug the attenuator into the input and plug your interconnect into that, this helps things like the sound stage.
Would you mind to explain your reasoning behind this?

Ralf

Spinner45
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Re: Old question, wrong answer

Post by Spinner45 » 14 Jun 2018 17:31

cafe_liegeois wrote:
hoolio wrote:If you have a separate pre and power amp then plug the attenuator into the input and plug your interconnect into that, this helps things like the sound stage.
Would you mind to explain your reasoning behind this?

Ralf
I assume the effect is like having a variable loudness control, with various benefits, depending on the equipment.

lini
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Re: Old question, wrong answer

Post by lini » 14 Jun 2018 22:17

P-l: The actual advantage would rather be that: Mistracking/channel imbalance is typically highest at the lowest volume control positions - so by delivering a weaker signal, requiring higher volume control positions, one can avoid the problematic range. I had that problem, too, with my hk825/hk870 combo - too small usable adjustment range and some imbalance showing up at very low listening levels. So I've simply built a custom cable with integrated voltage division myself -> problem solved.

A good idea in case of receivers and integrated amps can also be to integrate such an attenuator cable via an unused, full-featured (= with monitor function) tape-loop, so one can activate or deactivate it just as one likes... And of course that may also save some money, if one has got more than one source with rather hot output.

Greetings from Munich!

Manfred / lini

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