"System" SINAD

[boxerfan88]

Would the concept of "system" SINAD (from source to speakers) be useful in component selection for a good stereo system?

Let's assume a listening SPL of 85dB @ 1m, and a room noise floor of around 40dB SPL. Assuming +20dB headroom for signal peaks, and another -20dB noise headroom. A system SINAD of >85dB would be good enough for all materials out there...

Looking at component SINADs:

• DACs are running >100dB some even reaching 140dB
• Pre/Power/Integrated amps are typically >100dB
• Speakers look like the limiting component... i hazard a guess of around 40dB-50dB SINAD depending on the SPL levels being played
• Not sure how to factor the room into this picture, cables too...
  

Thoughts?

 

[MaxwellsEq]

Noise and distortion mechanisms for these components are all different. Our brains also act differently to different noise types and how well we can detect signals below the noise floor.

As a result, you can't actually say that acoustic noise from the room masks electronic noise from a power amplifier. Similarly, some distortion types are more egregious than others, even if they measure much lower. Both noise and distortion types act differently at different frequencies which is why SINAD is a useful index, but not the total story.

So, we're forced to minimise noise in each component and minimise distortion in each component in order to ensure the end to end transfer is as accurate as possible.

 

[IAtaman]

I think that is a very sensible way of looking at it : how much non-linearity is introduced to the sound from its last "bit perfect" state.

If you limit the system to mean "how accurately the pressure waves that reach my ear drum relate back to the digital data" I suscpect it might be posible to talk about a system SINAD. It would be a complicated calculation I suspect though as noise of one system will be input to the next which will be amplified with gain plus not all distortion is created equal so I am not sure how useful the outcome be to evaluate a system overall. Plus things gets a lot messier (non Charles version) when the last component of system comes into play i.e. the human perception. In my experience, almost all discussions about noise and distortion eventually converges in to a discussion about physio and psycho acoustics, types of distiortion and their audibility, which is not as well understood, say as the math behind sampling theory for example, so it turns into a "but can you consistently hear and detect, and distinguish it" discussion, which almost always takes us into the details of experimental method.

Also important to note, 140db SINAD figures you mentioned, I suspect they would probably be best case SINAD figures, so chaining best case values together might not be indicative for the actual performance of the system as a whole.

 

[restorer-john]

As a result, you can't actually say that acoustic noise from the room masks electronic noise from a power amplifier.

Not quite. I have the fan in the oven and the air conditioning on right now- it wouldn't matter what S/N my amplifiers had- I would hear zero residual hiss right now. S/N is irrelevant to me at 8:20pm as I type this. At 11:00pm, when the house and the entire valley and area is dead silent and I can hear a gnat fart, S/N is everything.

Power amplifiers make their own physical noise as well, some more than others. Many a transformer based amplifier will produce physical lamination hum/buzz which greatly exceeds the background noise level in a room. The physical noise trumps the electrical S/N and renders it meaningless.

I have disposed of many amplifiers with fantastic electrical measured performance, but dreadful acoustic performance. What is the point of >100dB S/N where the transformer and vibration noise wipes out 40dB of that, even into insensitive loudspeakers? If I can hear a transformer at 1M, it is a faulty design. If I can silence that noise by isolating, tightening lamination bolts or tweaking a steel wrap casework- maybe. But generally, noisy transformers are best moved on.

The S/N from end to end is a valid and very sensible way of looking at the high fidelity reproduction chain. Where loudspeakers are the primary transducer, you have the room and the environmental noise to consider. Where it is headphones, you have less 'room' to consider and everything else to account for, right down to the noise the hinges of the headphones make when you move your head or the pressure on your ears and how that translates to more noise you ultimately hear.

 

[IAtaman]

How much environmental noise impacts the perception of music is also a debatable topic in my opinion. I suspect there is reason to believe our brains have the necessary processing power to have their own active noise cancellation so to speak, that is, separate the continuous rumble of the oven fan for example and keep it away from perception.

On a somewhat related topic, I read an article in which it was claimed that the ultimate high end headphones would be the ones that cancels the outside noise, measures the on ear response close to real time (like airpods do) and continously adjusts the signal to provide you with a consistent frequency response regardless of exact fit and placement. I thought it was a cool idea but would probably sound artificial and weird at first, not sure if we would be able to develop a taste for them, but I am hopeful.

 

[MaxwellsEq]

Not quite. I have the fan in the oven and the air conditioning on right now- it wouldn't matter what S/N my amplifiers had- I would hear zero residual hiss right now. S/N is irrelevant to me at 8:20pm as I type this. At 11:00pm, when the house and the entire valley and area is dead silent and I can hear a gnat fart, S/N is everything.

Power amplifiers make their own physical noise as well, some more than others. Many a transformer based amplifier will produce physical lamination hum/buzz which greatly exceeds the background noise level in a room. The physical noise trumps the electrical S/N and renders it meaningless.

I have disposed of many amplifiers with fantastic electrical measured performance, but dreadful acoustic performance. What is the point of >100dB S/N where the transformer and vibration noise wipes out 40dB of that, even into insensitive loudspeakers? If I can hear a transformer at 1M, it is a faulty design. If I can silence that noise by isolating, tightening lamination bolts or tweaking a steel wrap casework- maybe. But generally, noisy transformers are best moved on.

The S/N from end to end is a valid and very sensible way of looking at the high fidelity reproduction chain. Where loudspeakers are the primary transducer, you have the room and the environmental noise to consider. Where it is headphones, you have less 'room' to consider and everything else to account for, right down to the noise the hinges of the headphones make when you move your head or the pressure on your ears and how that translates to more noise you ultimately hear.

I agree with everything you say. However, in your first paragraph you mentioned A/C and oven noise masking electronic hiss, which I would expect. But I wasn't talking about noise masking noise, so much as noise masking signals which is a different thing.

At university I had to build a thing that could, in the analogue domain, amplify a crystal's resonance when modulated by a laser. The signal was some 15dB below the noise floor. You couldn't see it on a scope, but because I knew what I was looking for, I could amplify it.

See also spread spectrum radar and SIGINT.

 

[Sokel]

For what it's worth that's what REW shows for my chain.
If I read it right noise is the dominant factor,distortions are above it:
(might be a little lower late at night)

 

[BDWoody]

Would the concept of "system" SINAD (from source to speakers) be useful in component selection for a good stereo system?

Here is a thread you may find interesting:

The Signal Chain: How do noise and distortion propagate through my system?

This article is to explore how noise and distortion change through our system, and how different components can influence the final output. A common question is “If I have DAC A, preamp B, and amp C, where should I set the volume and gain controls for the best performance?” Usually this...

audiosciencereview.com

 

[Mnyb]

In room noise levers are not always what we think , if you measure sure you get 30-40dB but that’s almost always low frequncies from trafic or hvac in the sensitive midrange and low treble where are hearing is good the noise level can be much lower in practice.

So in imho you can’t really have to low noise levels in your electronics

Distortion I don’t know my practical limits ?

I’ve read somewhere ( here at ASR maybe ) that Genelec consider that if the distortion of the internal amps driving thier speakers is always 10dB better than the transducers it drives . It would not matter anymore .

 

[tktran303]

For what it's worth that's what REW shows for my chain.
If I read it right noise is the dominant factor,distortions are above it:
(might be a little lower late at night)

View attachment 273040

I like this. Let’s try again at 86dB, 96dB and 106dB for that stretch goal.

Who’s up first?

 

[Sokel]

I like this. Let’s try again at 86dB, 96dB and 106dB for that stretch goal.

Who’s up first?

I'll do it but tomorrow where i'll be alone in my room,I'm really curious!

 

[tktran303]

Are you going to do it at 1m? Or listening position?

Turn off the HVAC hehe and see what the lowest noise floor is possible.

I might try too…

 

[Sokel]

Are you going to do it at 1m? Or listening position. I might try too…

MLP of course (2.8 meters) ,just like the one you see,that's the practical value.

 

[tktran303]

Yeah make sense. I wonder if any of our members hit the Dolby theatre specs (105dB @ MLP)

 

[Cote Dazur]

Would the concept of "system" SINAD (from source to speakers) be useful in component selection for a good stereo system?

Such a good question, with so may people spending so much time and attention on details that have little to no bearing on the final outcome.
A sound system works essentially as a chain, as any chain, it will always only be as strong as its weakest link. So the only important SINAD number is the chain SINAD, having a super SINAD link in there is irrelevant.
We all know ( or should ) what the weakest elements are, yet, most prefer to discuss irrelevant measurement numbers, as if those boxes where doing anything on their own.

 

[MaxwellsEq]

A sound system works essentially as a chain, as any chain, it will always only be as strong as its weakest link. So the only important SINAD number is the chain SINAD, having a super SINAD link in there is irrelevant

That's too simplistic. All noises are different and all distortions are different. That's why SINAD is useful, but it's a single number and tells you nothing about the nature of the noise or distortion.

 

[Cote Dazur]

That's too simplistic

I do not disagree, but it is even more "simplistic" to discuss ad nauseum about the merits of one link, when all that matters is the chain strength.

All noises are different and all distortions are different

Very true, as different as they are if they are masked by more prominent noises and distortion, the more prominent are to be dealt with first since the hidden ones will not be heard.

All I am saying is that, we, as individual, should concentrate on the final result of what we have in our environment, when, more often than not, 90% of the details of one particular gear has no importance.

 

[boxerfan88]

I asked ChatGPT, and i got interesting replies.

why is sinad important in hifi?

SINAD, which stands for "Signal-to-Noise and Distortion Ratio," is an important specification in Hi-Fi audio systems because it provides a quantitative measure of the audio system's ability to accurately reproduce audio signals while minimizing noise and distortion.

SINAD measures the ratio of the audio signal level to the total noise and distortion level of the audio system, expressed in decibels (dB). A higher SINAD value indicates a better audio system performance, with less noise and distortion.

In other words, a high SINAD value means that the audio system can reproduce audio signals with a high degree of accuracy and fidelity, without adding any unwanted noise or distortion. This is particularly important in Hi-Fi audio systems, where the goal is to reproduce audio signals as accurately and faithfully as possible, without adding any coloration or distortion to the original sound.

In summary, SINAD is an important specification in Hi-Fi audio systems because it measures the system's ability to accurately reproduce audio signals with minimal noise and distortion, which is essential for achieving high-fidelity sound reproduction.

what sinad is good enough for hifi?


The answer to what SINAD is good enough for Hi-Fi audio systems is subjective and can vary depending on individual preferences and the specific application.

Generally speaking, a SINAD of 90 dB or higher is considered very good and should be sufficient for most Hi-Fi audio systems. However, some audiophiles and audio professionals may prefer even higher SINAD values to ensure the highest possible audio fidelity.

It's also worth noting that SINAD is just one of many factors that contribute to the overall audio quality of a Hi-Fi system. Other factors such as frequency response, dynamic range, and distortion characteristics can also affect the overall sound quality.

Ultimately, the best way to determine whether a Hi-Fi audio system meets your specific needs and preferences is to listen to it and compare it with other systems. However, as a general rule of thumb, a SINAD of 90 dB or higher is a good benchmark to aim for in Hi-Fi audio systems.

what is a typical speaker sinad?


It's difficult to give a precise answer to this question since speaker SINAD is not typically measured or specified in the same way as SINAD for audio systems. Speaker specifications usually focus on parameters such as frequency response, impedance, sensitivity, and power handling, rather than SINAD.

SINAD is usually measured and specified for audio electronics such as amplifiers, digital-to-analog converters (DACs), and CD players. These components are responsible for processing and amplifying audio signals before they are sent to the speakers. Therefore, the SINAD of the audio electronics can have a significant impact on the overall sound quality of the system.

That being said, the SINAD of a speaker can indirectly affect the overall sound quality of the system. This is because the speaker's ability to accurately reproduce audio signals without adding distortion or noise can be limited by its own characteristics such as frequency response, distortion, and sensitivity. Therefore, it's important to choose speakers that have high-quality drivers and are well-engineered to minimize distortion and noise.

In summary, while speaker SINAD is not typically measured or specified, the overall sound quality of a Hi-Fi system can be affected by the quality of the speakers as well as the audio electronics that drive them.

I was very surprised the 90dB figure came so close to the 85dB figure I posted in the OP (derived from listening level & room background noise level). How did that 90dB figure come about?

 

[Sokel]

Yeah make sense. I wonder if any of our members hit the Dolby theatre specs (105dB @ MLP)

So be it then:
(REW wouldn't let me go louder,it said something about changing mic's ref level,but it's easy to see levels relative to noise floor)
((No EQ,no nothing,just out of curiosity))


All:

85db SPL + Percentage

95db SPL+ Percentage:

100db SPL+Percentage:

I think it doesn't go very happy after that

 

[-Matt-]

@Sokel Thanks for taking those measurements and sharing them. Very interesting.

The amount of distortion looks terrible, but I don't have a good frame of reference for such whole system measurements. I bet it is actually a very good result and my own system (that subjectively sounds good) might do a lot worse. It seems like a very good way of testing and maybe trouble-shooting our setups.

Perhaps you have posted details of your system elsewhere, but could you please re-post them here so that we can corellate them with the measurements?