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Digital Audio and Amplifier Noise Floor Comparison - Is 16bit/44.1kHz All We Need ???


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5 minutes ago, Rt66indierock said:

 

My Heresy II speakers are 96 dB so I need a little more.

 

Those are measures of efficiency.  Your Heresy's only require roughly 1/10th the power to reach the same sound levels as a speaker with 86db efficiency. 

 

Anyone who considers protocol unimportant has never dealt with a cat DAC.

Robert A. Heinlein

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25 minutes ago, esldude said:

You do realize with most speakers being about 86 db for one watt you only need -86 db to get everything down to 0 db SPL when measuring at 1 watt.  When taking into account Fletcher-Munson you can probably have complete perceptual silence with even less.  I'm all for good performance, but the idea you need THD+N this low is a little over the top for 1 watt.  And for most good amps you really are going to being talking about N(oise).  

It's a great point.  Likewise, this is the kind of thinking that makes sense regarding whether dithered 16 bit audio gives enough resolution - consider realistic peak SPL and room noise.

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9 minutes ago, Paul R said:

 

Those are measures of efficiency.  Your Heresy's only require roughly 1/10th the power to reach the same sound levels as a speaker with 86db efficiency. 

 

 

My Heresy's hiss a little with an amp that is quiet with the speakers in my office that are approximately 86 dB efficiency.  

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50 minutes ago, psjug said:

I can't find any numbers or curves showing THD+N at 1W for that amp.  The neuorochrome modulus stuff also looks like it may meet the 96dB at 1W, but the unit reviewed on ASR is not quite there.

 

Edit:  The ASR test of the neurochrome amp  is only slightly worse than the manufacturer curve (apparently due to intentional enclosure compromise), and this is into 4 ohms.  THD+N into 8 ohms is better for this amp - I think it may meet the 96dB at 1W mark.

Hi,
i do not know - does ASR measure to 1Watt into 8ohms? for all its S/N ? It is not specified for the Benchmark. The review states :

 

"Wow, assuming you play at peak of 120 dBSPL, your noise floor will be at -10 dBSPL! That is absolute silence."

 

If you play at this level, then THD rises, so not sure -10dB SPL is accurate. The 120dB SPL refers to 34dB power (2.5kWatts) for a 86dB sensitivity speaker. This exceeds the Benchmark capability.

 

The RANE site is good for the explanations - the parameters need to be stated for any S/N figure ;

https://www.rane.com/note145.html

 

Stereophile specification list for the Benchmark AHB2 does not list the parameters for the 130dB S/N except that it is A weighted.

 

Regards,

Shadders.

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1 minute ago, Rt66indierock said:

 

My Heresy's hiss a little with an amp that is quiet with the speakers in my office that are approximately 86 dB efficiency.  

You might need a little quieter amp at 1 watt yes.  I was using the number closer to average.   If you had K-horns in an appropriate room, it would be an even bigger issue for you. 

And always keep in mind: Cognitive biases, like seeing optical illusions are a sign of a normally functioning brain. We all have them, it’s nothing to be ashamed about, but it is something that affects our objective evaluation of reality. 

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5 minutes ago, Shadders said:

Hi,
i do not know - does ASR measure to 1Watt into 8ohms? for all its S/N ? It is not specified for the Benchmark. The review states :

 

"Wow, assuming you play at peak of 120 dBSPL, your noise floor will be at -10 dBSPL! That is absolute silence."

 

If you play at this level, then THD rises, so not sure -10dB SPL is accurate. The 120dB SPL refers to 34dB power (2.5kWatts) for a 86dB sensitivity speaker. This exceeds the Benchmark capability.

 

The RANE site is good for the explanations - the parameters need to be stated for any S/N figure ;

https://www.rane.com/note145.html

 

Stereophile specification list for the Benchmark AHB2 does not list the parameters for the 130dB S/N except that it is A weighted.

 

Regards,

Shadders.

https://www.audiosciencereview.com/forum/index.php?threads/review-and-measurements-of-benchmark-ahb2-amp.7628/

 

If you look at the chart graphing THD+N for all power levels you see it around .0005% for 1 watt for 4 ohm load.  This would be - 106 db at 1 watt, and is almost fully noise.  

 

The comment about playing at 120 db SPL would of course require a better than 86 db speaker.  Meaning with any less efficient speaker at a lower SPL the noise and distortion of the amp are going to be well below 0 db SPL in the listening area.  

And always keep in mind: Cognitive biases, like seeing optical illusions are a sign of a normally functioning brain. We all have them, it’s nothing to be ashamed about, but it is something that affects our objective evaluation of reality. 

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2 minutes ago, esldude said:

https://www.audiosciencereview.com/forum/index.php?threads/review-and-measurements-of-benchmark-ahb2-amp.7628/

 

If you look at the chart graphing THD+N for all power levels you see it around .0005% for 1 watt for 4 ohm load.  This would be - 106 db at 1 watt, and is almost fully noise.  

 

The comment about playing at 120 db SPL would of course require a better than 86 db speaker.  Meaning with any less efficient speaker at a lower SPL the noise and distortion of the amp are going to be well below 0 db SPL in the listening area.  

Hi,

If we assume 200watts in 8ohms specification for the amplifier (i think it is specified at 100watts), then 200watts is 23dB. The SPL 120dB - 23dB = 97dB sensitivity speaker. Not many speakers in that range. I quoted 86dB as this is more probable. Even a 90dB sensitivity speaker requires 1kW amplifier.

 

Is it not the issue that, the lower sensitive speaker requires the amplifier to provide a greater power, increasing THD and hence the stated 120dB SPL etc. statement is not relevant ???

 

The issue is also, the 130dB figure measured - what were the parameters for this measurement ? If 1watt into 4ohms is -106dB due to THD, then how is -130dB S/N achieved in the test - what were the parameters ?

 

I think the relevance to MQA here is that the noise floor of CD is sufficient, and high resolution is not needed - since any music will mask any noise artefacts, especially at -106dB noise floor, making -130dB a nice figure, but irrelevant ??.

 

Regards,
Shadders.

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28 minutes ago, Shadders said:

Hi,

If we assume 200watts in 8ohms specification for the amplifier (i think it is specified at 100watts), then 200watts is 23dB. The SPL 120dB - 23dB = 97dB sensitivity speaker. Not many speakers in that range. I quoted 86dB as this is more probable. Even a 90dB sensitivity speaker requires 1kW amplifier.

 

Is it not the issue that, the lower sensitive speaker requires the amplifier to provide a greater power, increasing THD and hence the stated 120dB SPL etc. statement is not relevant ???

 

The issue is also, the 130dB figure measured - what were the parameters for this measurement ? If 1watt into 4ohms is -106dB due to THD, then how is -130dB S/N achieved in the test - what were the parameters ?

 

I think the relevance to MQA here is that the noise floor of CD is sufficient, and high resolution is not needed - since any music will mask any noise artefacts, especially at -106dB noise floor, making -130dB a nice figure, but irrelevant ??.

 

Regards,
Shadders.

Well the statement about 130 db and noise level being -10 db SPL comes after the SNR measurement.  He basically used the definition in the Rane link posted up thread.  Max power/noise with no input signal.  So at max power THD+N would be about -116 db, but vs silence the ratio measured is 130 db.  Those harmonics of distortion well below -110 db are going to be masked if you were playing music. As the level of the music varies noise is always going to be below being heard right down to silence as the input.  So the statement is accurate.  22 khz bandwidth, I think a 4 ohm load.  

And always keep in mind: Cognitive biases, like seeing optical illusions are a sign of a normally functioning brain. We all have them, it’s nothing to be ashamed about, but it is something that affects our objective evaluation of reality. 

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1 hour ago, Rt66indierock said:

 

My Heresy's hiss a little with an amp that is quiet with the speakers in my office that are approximately 86 dB efficiency.  

 

You probably need a little quieter amp for those guys, unless you only hear hiss while there is silence within a track.  They are very sensitive little champs. In comparison, my desktop monitors are 83.5dB/2.83v/m.  It takes a lot more power to drive them up to high SPLs, but it takes a really noisy amp to get them to hiss. 

Anyone who considers protocol unimportant has never dealt with a cat DAC.

Robert A. Heinlein

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6 hours ago, Shadders said:

Hi,

Sandyk can confirm this, but the specification for the SC200 was measured for the completed amplifier - not simulation. The ULD was also the measured performance. If you purchase the kits/PCB, and follow the article instructions, then you will achieve the measured performance.

Regards,

Shadders.

Richard is correct.

Note also that in the specifications for the  S.C. ULD 3 they also quote typical and maximum distortion figures.

Silicon Chip magazine does not go out of their way to select matched pairs either, so their figures can possibly be improved on a little.

 The kits are supplied with generic electrolytic and normal type capacitors, so it is also possible to use higher quality types in their place, as well as the use of very low noise resistors such as naked bulk metal film resistors in areas such as the gain setting, and use matched .1% resistor pairs in other areas such as the differential pair and current mirror. In fact, you can also purchase a few extra devices as used in the differential pair and current mirrors areas later if you are so inclined, and retrofit closely matched pairs in those areas for a further small improvement. All this can be done at quite a modest additional expenditure.

 All of this is something that I normally do, and the improvements can be heard.

 I don't have access to the original article for the SC200 which is mainly based around the older SC ULD3/4 but uses some surface mount components.  I can however provide full relevant info for the SC ULD3 via PM if requested . 

 

How a Digital Audio file sounds, or a Digital Video file looks, is governed to a large extent by the Power Supply area. All that Identical Checksums gives is the possibility of REGENERATING the file to close to that of the original file.

PROFILE UPDATED 13-11-2020

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1 hour ago, Shadders said:

Hi,

Not sure how he calculated - the Rane article states :

 

Required Conditions. In order for the published figure to have any meaning, it must include the measurement bandwidth, including any weighting filters and the reference signal level. Stating that a unit has a “S/N = 90 dB” is meaningless without knowing what the signal level is, and over what bandwidth the noise was measured. For example if one product references S/N to their maximum output level of, say, +20 dBu, and another product has the same stated 90 dB S/N, but their reference level is + 4 dBu, then the second product is, in fact, 16 dB quieter.

 

The 130dB has to be referenced to a specific output level. The ASR review is not clear on what output signal level is being used.

Regards,

Shadders.

Low gain, max power, 22.5 khz measurement bandwidth.   I believe power was 185 watts 4 ohm load.  Benchmark specs a few more watts at 4 ohms, but at .0003% rather than .00016% distortion in the test over at ASR.  So roughly 27 volts output.  Low gain is 9.2 db of gain.  Done at 1 khz. 

 

So they get fraction over 130 db for SNR.  Specs quoted by Benchmark I think indicate 131.5 at a very slightly higher output.  So we are down to quibbling about a db or so.  

 

Benchmark AHB2 Amplifier SNR Audio Measurements.png

 

The reviews at ASR are meant for a wider audience without needing to be an EE.  I truly wish everyone would use carefully delineated conditions in their testing like Rane suggests.  But with a little looking you can find enough to figure it out the case of this review what those parameters were.  Nothing in the Stereophile measures really contradict the results.  I've seen measurements done on another site and again everything is down to a couple db of the same results.  

 

So I don't think anything is misleading about any of this. Like is always the case, and something many don't carefully consider, to get the most of gear in terms of SNR and dynamic range you'll need to gain stage everything carefully.  The Benchmark helps by having 3 different levels of gain for the input. Low gain helps a couple db on everything versus higher gain settings. 

 

Benchmark specifies many different operating conditions beyond your normal spec sheet here:

https://benchmarkmedia.com/products/benchmark-ahb2-power-amplifier

And always keep in mind: Cognitive biases, like seeing optical illusions are a sign of a normally functioning brain. We all have them, it’s nothing to be ashamed about, but it is something that affects our objective evaluation of reality. 

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Yes.

 

Over 3 decades ago it was possible to get SQ as good as one could want from CDs, using well done amplifiers  of the day - the "noise floors" of the latest systems, meaning taking everything into account, beyond just the amplifier, are much better than they used to be - but still fall well short of 'testing' the limits of Redbook.

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Thanks for making the new thread.  I vote Yes as well.  Maybe amplifiers can be better than 16 bit equivalent, but doesn't room noise kill the possibility of realizing that much dynamic range in practice?

Edit: I didn't notice the 44.1.  That one is a little more tricky I'd say, but my vote would still be yes.

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Thinking a sound level meter shows noise levels in my listening room of say 35 db SPL means that sets a lower limit is deceptive.  Most room noise is heavily weighted toward low frequencies.  If you split the bands up like our ears do, in our most sensitive frequencies 3-5 khz most rooms are anywhere from 0 db SPL to 10 db SPL in that range.  Some treated studios can be -10 db SPL in that range. We also can hear into noise 10 or 15 db as well.  So as a basic starting point I would suggest we assume 0 db SPL as our in room noise floor. 

And always keep in mind: Cognitive biases, like seeing optical illusions are a sign of a normally functioning brain. We all have them, it’s nothing to be ashamed about, but it is something that affects our objective evaluation of reality. 

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30 minutes ago, Shadders said:

This is the discussion on whether Red Book CD (RBCD) is all we need fro audio reproduction given that amplifiers may or may not have a lower noise floor.

 

Noise floor?  Do you mean dynamic range?  

 

If you’re happy with Redbook, I don’t think you’ll find anyone here that will say you’re wrong, because you’re not.

 

Listening to music is a deeply personal experience and if you’re happy with your system then that’s great! Tell us what you like about it!

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37 minutes ago, Shadders said:

This is the discussion on whether Red Book CD (RBCD) is all we need fro audio reproduction given that amplifiers may or may not have a lower noise floor.

 

Any modern amplifier that doesn't have a S/N in EXCESS of 110dB is poorly designed !!!

 

How a Digital Audio file sounds, or a Digital Video file looks, is governed to a large extent by the Power Supply area. All that Identical Checksums gives is the possibility of REGENERATING the file to close to that of the original file.

PROFILE UPDATED 13-11-2020

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15 minutes ago, psjug said:

  Maybe amplifiers can be better than 16 bit equivalent, but doesn't room noise kill the possibility of realizing that much dynamic range in practice?

 

 Why ? Many people listen to music at quite high SPLs, often in excess of the requirements of the source material.

Why limit this to just RBCD when many people even listen to TV via their main system, and that may also include music videos .

 With TV audio the max. level is limited anyway to suit the medium, but dialogue etc,. is often listened to at higher than the original voice levels. 

 

How a Digital Audio file sounds, or a Digital Video file looks, is governed to a large extent by the Power Supply area. All that Identical Checksums gives is the possibility of REGENERATING the file to close to that of the original file.

PROFILE UPDATED 13-11-2020

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11 minutes ago, esldude said:

Thinking a sound level meter shows noise levels in my listening room of say 35 db SPL means that sets a lower limit is deceptive.  Most room noise is heavily weighted toward low frequencies.  If you split the bands up like our ears do, in our most sensitive frequencies 3-5 khz most rooms are anywhere from 0 db SPL to 10 db SPL in that range.  Some treated studios can be -10 db SPL in that range. We also can hear into noise 10 or 15 db as well.  So as a basic starting point I would suggest we assume 0 db SPL as our in room noise floor. 

That's a really good point.  But do really think 0 dB is a realistic assumption.  What is the perceived level and FR of normal breathing, for example?

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24 minutes ago, esldude said:

Thinking a sound level meter shows noise levels in my listening room of say 35 db SPL means that sets a lower limit is deceptive.  Most room noise is heavily weighted toward low frequencies.  If you split the bands up like our ears do, in our most sensitive frequencies 3-5 khz most rooms are anywhere from 0 db SPL to 10 db SPL in that range.  Some treated studios can be -10 db SPL in that range. We also can hear into noise 10 or 15 db as well.  So as a basic starting point I would suggest we assume 0 db SPL as our in room noise floor.  

 

Yes, that is food for thought.

 Let's not get into the area of how loud breathing can sound though.:D

Quote

If you’re happy with Redbook, I don’t think you’ll find anyone here that will say you’re wrong, because you’re not. - SJK

That is a very valid point, with a large % of members preferring high res and DSD over RBCD. 

 

How a Digital Audio file sounds, or a Digital Video file looks, is governed to a large extent by the Power Supply area. All that Identical Checksums gives is the possibility of REGENERATING the file to close to that of the original file.

PROFILE UPDATED 13-11-2020

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4 minutes ago, sandyk said:

 

 Why ? Many people listen to music at quite high SPLs, often in excess of the requirements of the source material.

Why limit this to just RBCD when many people even listen to TV via their main system, and that may also include music videos .

 With TV audio the max. level is limited anyway to suit the medium, but dialogue etc,. is often listened to at higher than the original voice levels. 

 

I'm not sure I am following you.  Are you saying it is nice to have extra amplifier dynamic range to account for level mismatches when paired with multiple sources?  I can buy that argument.

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8 minutes ago, psjug said:

That's a really good point.  But do really think 0 dB is a realistic assumption.  What is the perceived level and FR of normal breathing, for example?

Isn't there a meme about hearing people breathe?  Like "if I can hear you breathing, I have fantasized about your death" or something?  Or is it chewing that bothers most people?  I personally don't want to hear chewing or breathing!

 

Sorry for the OT!

请教别人一次是5分钟的傻子,从不请教别人是一辈子的傻子

 

 

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4 minutes ago, Hugo9000 said:

Isn't there a meme about hearing people breathe?  Like "if I can hear you breathing, I have fantasized about your death" or something?  Or is it chewing that bothers most people?  I personally don't want to hear chewing or breathing!

 

Sorry for the OT!

But if you hear your own breathing, what does that mean?

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