How Loud is 1 Watt?

[fas42]

3 hours ago, accwai said:

 

But regardless, 7w per channel amp feeding crossoverless 98dB 1W/1m speakers would seriously disturb everybody elsewhere in the house well before the combo itself exhibit any kind of stress. So there could well be something to the 1w is loud enough claim. Or not...

 

Very much true ... a competent 10 to 30W amplifier, driving just ordinary sensitivity speakers, will completely dominate the acoustic environment of a house. In exactly the same way as a group of musicians playing live in some room of your home,would "take over" your home - as far as your ears were concerned. The quality of that sound travels a long way, and is instantly identifiable ...

[fas42]

1 hour ago, Don Hills said:

 

My interest is in advances in audio reproduction, especially the largest unsolved problem, the transduction of electric to acoustic energy. As such, I see little innovation in home audio. All the work is going on at the two ends of the field - PA and cell phones. For example, exotic fillers used in the back chamber of cell phone speakers to increase the apparent volume. Like the relationship of race cars to family autos, the technology is interesting and some of it will eventually filter down into home audio.

 

Tom Danley is keen on the creating of the "invisible speaker" behaviour - and I just tracked down a post I remembered, where he talks of his way of approaching this - which happens to be a response to a post of mine, 🤪,

 

https://www.diyaudio.com/forums/the-lounge/146693-john-curls-blowtorch-preamplifier-ii-post4202110.html

 

[PeterSt]

13 hours ago, accwai said:

So exactly which part of the power supply would be heating up when current demand on the amp side increases?

 

Easy enough: the voltage regulation(s).

 

More easy enough: the ambient of the power supply (other voltage regulations, transformer, a 1 million sllicon chips (if solid state), name it - in the end also resistors of course).

 

It's like a deadly circle; all of these components create heat which already induces self-collapse when not taken care of. This is why heat-dissipation in PCB design is a crucial part of the design.

[PeterSt]

13 hours ago, accwai said:

There is no such thing as difficult transient as far as the power supply goes, in theory at least. Is this correct?

 

I don't think so, but it obviously depends on the device. For example:

 

You may not realize it, but a bit of CPU which is rated at 100W, is capable of boosting up the current requirements from about 0 to 100W (or 20A if you want) in nanoseconds. I'd call that a pretty severe transient;

Now you know why power supplies for a PC are switching power supplies - this means allows these transients without delivering the 100W continuously (that would unnecessarily heat up the PC internally with the known result 😝).

 

... And now you also know why making a linear power supply for the same CPU's hence PC's, is quite a task.

 

Mind you please ... I am mentioning the 100W as example (and not 1000W which is quite common for gamers) because I still try to talk Audio Terms. Thus indeed these PC's exist, as we well know.

[PeterSt]

An additional phenomenon you most probably won't know about:

 

When the power supply of a PC is insufficient (hence the voltage drop because of current requirement is too high), then the PC will shut down. Ah, well, you knew that because this is just the ATX specification and the ATX power supply will just shut down the system. But what you did not think of, is that a power amplifier (etc.) which demands a higher current because of the music content, really behaves the same in the power supply department. One difference: nothing will shut down.

 

... Instead you should be able to hear this ...

 

So the more "infinite" the power supply can supply (current) the less impact the (music) demand will influence;

If a power supply delivers 100%, music can draw that 100% but the influence the music implies on itself will also be 100%.

If the power supply is so over-specified that the same level of music implies only 1% of its capabilities, the influence on the music itself is also 1% only.

 

Not to forget: it is all about how long a demand can be sustained (for delivery). This can be about Mahler in its wildest moments (loud level), but it can just as well be about the rendering of high frequency cymbals for a longer time (sustaining higher frequency transients).

[phusis]

18 hours ago, audiobomber said:

Are you saying other pro audio companies can't do this? I have no idea, and no real interest, because Public Address is not a part of my audiophile hobby. I'm not interested in car audio either, nor in musical instruments and ancillary amplification, or other tangentially related topics. My interest is in great sounding home audio, which sounds a million times better than these PA videos. 

 

Re: resistance to wind gusts, actually no - other pro audio companies can't follow this feat of Danley's due to their speakers (i.e.: the ones not Danley) not acting as point sources. As others here have mentioned already the video of Danley's Jericho speaker sounding that clear over a distance of 1,200 to 1,500 feet is a an amazing pull-off, indeed a display of true engineering prowess, and so the perceived sonic impression of the Jericho's as heard through supplied video above must be put into proper perspective to be appreciated.

 

"My interest is in great sounding home audio, which sounds a million times better than these PA videos." 

 

Mine too, and it should be obvious by now that a video of PA speakers like the one mentioned isn't a telling representation of their abilities in a home setting, but it's still an interesting one in the context of domestic sound reproduction; emulating a true point source with correct time and phase behavior is one of the primary feats, if not the Holy Grail of audio reproduction at large - that is, without the sacrifices typically associated with the use of full-range or coaxial drivers. That's something Tom Danley has dodged with the invention of the (patented) Synergy Horns, and it's miles ahead of any minutiae that "hi-fi" for the most part has been noodling with for decades without making essential progress. Add to that proper dynamic capabilities, ample headroom (indeed huge headroom in the bass where hearing gets less sensitive) and frequency extension down to at least 25-30Hz, and then we can start fiddling with minutiae - at least to some degree. 

 

Great sounding home audio to me is trying to achieve these broad, fully scoped outlines of the "audio canvas" we paint on, first and foremost, instead of focusing primarily on the finer brushstrokes in a limited section of the canvas, the latter of which I find to be the domain predominantly of typical audiophilia. At least that's my conceptualization of it. That's not to say this approach leaves subtlety and resolving abilities by the wayside, far from it, indeed I find these are traits successfully accommodated this way - not least run fully actively. I can't yet pride myself of Synergy Horn main speakers, but one day down the line I will. For now pro cinema speakers and tapped horn subs (with excellent drivers) does the job admirably, be that with classical music, jazz, house/trance/techno, blues, pop/rock, etc. 

[accwai]

5 hours ago, PeterSt said:

Easy enough: the voltage regulation(s).

 

Your mean series regulator in an amp's output stage power supply? If nothing else, would adding another layer of active devices into the signal chain really be a good idea?

 

5 hours ago, PeterSt said:

I don't think so, but it obviously depends on the device.

 

The context was only single ended amp...

[sandyk]

8 hours ago, accwai said:

Your mean series regulator in an amp's output stage power supply?

 The vast majority of Linear amplifiers do not use voltage regulation of the output stages, although some lower power Class A amplifiers such as my 15W/channel do. They rely mainly on large value filter capacitors, (10,000uF for example) with often several in parallel on both the +VE and -VE supply rails. Many Power Amplifiers will however use voltage regulation of the front end (signal amplification area) of the amplifier. 

[fas42]

14 hours ago, PeterSt said:

 

Easy enough: the voltage regulation(s).

 

More easy enough: the ambient of the power supply (other voltage regulations, transformer, a 1 million sllicon chips (if solid state), name it - in the end also resistors of course).

 

It's like a deadly circle; all of these components create heat which already induces self-collapse when not taken care of. This is why heat-dissipation in PCB design is a crucial part of the design.

 

As Alex points out, voltage regulation is not part of most output stages of conventional amps - so I still don't see where this supposed heat problem is ...

 

I did my own design of a chip amp years ago, using the LM3875 - this had voltage regulation on it, and  I spent a lot of time getting the PS "right" - in terms of space used, the overall thing was 95% power supply, the actual amplifying bit was almost invisible; hidden behind big heat sinks, capacitors, etc. Getting rid of heat is critical - as an experiment, ran it without being firmly attached to the heat sink... it shut down, from internal protection, very, very quickly.

[fas42]

Conventional power supplies have an inherent problem, that of getting enough current flow through the rectifying diodes for a long enough time to top up the smoothing caps - only the peak of the mains voltage swing actually delivers any current. For there to be more time for current to flow, the voltage on the caps has to fall; so that the diodes will conduct over a longer period - this automatically means the voltage rails drop, when lots of power is needed; ultimately, the amp will clip.

 

There are ways of getting around this; but they are rarely used.

[fas42]

12 hours ago, phusis said:

 

Great sounding home audio to me is trying to achieve these broad, fully scoped outlines of the "audio canvas" we paint on, first and foremost, instead of focusing primarily on the finer brushstrokes in a limited section of the canvas, the latter of which I find to be the domain predominantly of typical audiophilia. At least that's my conceptualization of it. That's not to say this approach leaves subtlety and resolving abilities by the wayside, far from it, indeed I find these are traits successfully accommodated this way - not least run fully actively. I can't yet pride myself of Synergy Horn main speakers, but one day down the line I will. For now pro cinema speakers and tapped horn subs (with excellent drivers) does the job admirably, be that with classical music, jazz, house/trance/techno, blues, pop/rock, etc. 

 

The good news is that one can "get it all" - home audio can deliver intense sound levels, while retaining beautiful transparency and clarity. Something like a Jimi Hendrix blues track, at realistic levels - his guitar amp is in the room, completely 'pressurising' the space; at the same time, every subtlety of the drums is delivered, the transient tap of a stick on the cymbals is beautifully rendered - this is amazing stuff to experience; the promise of richness of music, for any track, is fully delivered.

[sandyk]

17 minutes ago, fas42 said:

I did my own design of a chip amp years ago, using the LM3875 - this had voltage regulation on it,

 

 Peter has previous wide experience of " gain clone" type amplifiers such as this, as I have had also.

However , due to his current very high efficiency speakers, he would need the lowest noise possible amplification.

[fas42]

1 minute ago, sandyk said:

 

 Peter has previous wide experience of " gain clone" type amplifiers such as this, as I have had also.

However , due to his current very high efficiency speakers, he would need the lowest noise possible amplification.

 

I find it interesting that some people seem to create rigs that are noisy, when idling - for whatever reason, the gear I've played with is dead quiet ... on  maximum gain, with ear against tweeter, I don't hear anything - only the NAD combo, at one point in time, got noisy like this - forgot what I did to resolve this, but I got rid of the issue.

[PeterSt]

7 hours ago, fas42 said:

I find it interesting that some people seem to create rigs that are noisy, when idling - for whatever reason, the gear I've played with is dead quiet ... on  maximum gain, with ear against tweeter, I don't hear anything

 

But what was the efficiency of the speaker(s) you used ?

You know the story about the 6dB more implies twice the power in theory, right ? So if you would be using a 94dB efficient speaker (mind you, measured at 1m and not "somewhere" like the video in the OP implies), and you would be using a 250W amp for that (never mind RMS mesured or not), then this would be similar to 250 x 2 x 2 x 2 x 2 in my situation (118dB). Now let me see ... that would be a 4000W amp.

Then try it again at full gain with your ear against the tweeter. 🤪

[PeterSt]

7 hours ago, fas42 said:

the rectifying diodes

 

They surely create heat too.

[PeterSt]

I actually can't envision how to avoid regulators in a good SS design. They are all over the place for various reasons. I mean, we won't have separate power supplies for e.g. 16V, 5V, 3V and 1.1V, right ? so that is reason one.

Reason two is the noiseless (as in PSSR) regulation, hence a best clean supply (like for oscillators, but so much more).

 

Maybe it is good to see that I am talking SMD/SMT components only, and that this is a quite different world from the huuuge thru-hole (legged) elements. So where the latter are usually inherently noisy to begin with, the small stuff was created to be more noise free (and maybe to save space). So mind you (also talking to Alex), we can do this all in-house and use 0402 size components where applicable (you can't even see those - it's like sand dust). So when I think of something today, next week I'll have it up and running, all soldered to a PCB (the week is necessary for the production of the PCB itself).

I don't think many people (companies) (can) work like this (which is all about speed of development - iterations).

[sandyk]

1 hour ago, PeterSt said:

I actually can't envision how to avoid regulators in a good SS design. They are all over the place for various reasons. I mean, we won't have separate power supplies for e.g. 16V, 5V, 3V and 1.1V, right ? so that is reason one.

Reason two is the noiseless (as in PSSR) regulation, hence a best clean supply (like for oscillators, but so much more).

 I agree, however this thread is more about the amount of power needed to provide a satisfactory level of sound into typical speakers via a power amplifier of some kind . 

 Very few power amplifiers need multiple separate power supply rails., with not even all using voltage regulation for the front end.

In any event, Johnson noise is a limiting factor in just how quiet a power amplifier can be., although it will help if the source such as a DAC is capable of driving a much lower input resistance amplifier than typical.

[fas42]

15 hours ago, PeterSt said:

 

But what was the efficiency of the speaker(s) you used ?

You know the story about the 6dB more implies twice the power in theory, right ? So if you would be using a 94dB efficient speaker (mind you, measured at 1m and not "somewhere" like the video in the OP implies), and you would be using a 250W amp for that (never mind RMS mesured or not), then this would be similar to 250 x 2 x 2 x 2 x 2 in my situation (118dB). Now let me see ... that would be a 4000W amp.

Then try it again at full gain with your ear against the tweeter. 🤪

 

Normal of course ... having a rail to rail signal from a 250W amp driving 118dB sensitivity speakers would be rather interesting, to say the least, 😁. In that case, adjust the gain to the highest one would use in any sane listening session - for that setting, a good design of the amp should still ensure essentially no audible noise 🙂.

[fas42]

15 hours ago, PeterSt said:

 

They surely create heat too.

 

The classic, square diode bridge rectifier is normally used for any higher powered unit - which is bolted to some heat sinking surface ... not much chance of overheating the silicon, I would think.

[fas42]

14 hours ago, sandyk said:

 I agree, however this thread is more about the amount of power needed to provide a satisfactory level of sound into typical speakers via a power amplifier of some kind . 

 

 

Having monster power amplifiers is in fact completely  unnecessary - but, the reason they sound better, is because they have bigger power supplies, to be able to meet their specs! The job gets done, in an indirect way - no one would buy an amp costing a great deal because of the competence of the PS, with only low numbers for the output power 😜.

 

10's of watts is all that's needed, to deafen one - my current active speakers only have 50W driving the mid/bass; and they have no trouble filling the room with SPLs where one has to shout to be heard, if the other is at any distance away.

[sandyk]

19 minutes ago, fas42 said:

Having monster power amplifiers is in fact completely  unnecessary - but, the reason they sound better, is because they have bigger power supplies, to be able to meet their specs!

 NOT necessarily.

 To obtain much higher output powers you would need to have  several output transistors in parallel. Large power transistors also have quite a bit of input capacitance, and this increases with the number of parallel output devices.
Then there is the much lower input impedance of the pile of output devices as well .
This much heavier loading also reflects back into earlier stages of the amplifier,  degrading the performance before negative feedback, as well as most likely resulting in overall distortion figures well in excess  of what can be obtained these days with amplifiers designed to suit more modest  output powers.

 

 

[phusis]

On 12/4/2020 at 11:26 PM, fas42 said:

 

The good news is that one can "get it all" - home audio can deliver intense sound levels, while retaining beautiful transparency and clarity. Something like a Jimi Hendrix blues track, at realistic levels - his guitar amp is in the room, completely 'pressurising' the space; at the same time, every subtlety of the drums is delivered, the transient tap of a stick on the cymbals is beautifully rendered - this is amazing stuff to experience; the promise of richness of music, for any track, is fully delivered.

 

From my chair the most laborious part in "having it all," by and large, is accommodating sheer physics and implementation; not the typical, flimsy hi-fi approach of mostly quite costly, low efficiency, usually passively driven and small to moderately sized speakers. The interesting part is that the former approach, while physically and practically more imposing, can be had much cheaper, though it is likely to involve some combination of DIY, entrepreneurial spirit, open mindedness or even a bit of a rebellious attitude when faced with audiophilia at large. I can honestly say I'm no longer invested giving much thought to über-expensive high-end audio gear, or hi-fi gear in general, as something I'd want to own, not to say what I currently have and strive for can't be made to sound even better, but what it takes to get there isn't as much an economical hindrance than simply setting out to do it - with all that entails practically - which is an encouraging thought. What I have now though is so joy-inducing and fulfilling, even and still surprisingly so, that I'm in no hurry just yet to venture out anew. Sometimes, preferable more often than not, it's just a wondrous thing to sit back and take it all in, with nary a thought of what's next on the menu..

[fas42]

56 minutes ago, sandyk said:

 NOT necessarily.

 To obtain much higher output powers you would need to have  several output transistors in parallel. Large power transistors also have quite a bit of input capacitance, and this increases with the number of parallel output devices.
Then there is the much lower input impedance of the pile of output devices as well .
This much heavier loading also reflects back into earlier stages of the amplifier,  degrading the performance before negative feedback, as well as most likely resulting in overall distortion figures well in excess  of what can be obtained these days with amplifiers designed to suit more modest  output powers.

 

 

 

Alex, the point I'm making is that the actual output power of the amp, as something measurable, doesn't have to be that large a number. 50 competent watts is vastly better, subjectively, than 1000W poor quality watts ... so a quick way there is, build a PS that can deliver to a 1000W unit, and instead put it into the 50W amp - and you mostly likely will be well ahead 😉.

[fas42]

27 minutes ago, phusis said:

 

From my chair the most laborious part in "having it all," by and large, is accommodating sheer physics and implementation; not the typical, flimsy hi-fi approach of mostly quite costly, low efficiency, usually passively driven and small to moderately sized speakers. The interesting part is that the former approach, while physically and practically more imposing, can be had much cheaper, though it is likely to involve some combination of DIY, entrepreneurial spirit, open mindedness or even a bit of a rebellious attitude when faced with audiophilia at large. I can honestly say I'm no longer invested giving much thought to über-expensive high-end audio gear, or hi-fi gear in general, as something I'd want to own, not to say what I currently have and strive for can't be made to sound even better, but what it takes to get there isn't as much an economical hindrance than simply setting out to do it - with all that entails practically - which is an encouraging thought. What I have now though is so joy-inducing and fulfilling, even and still surprisingly so, that I'm in no hurry just yet to venture out anew. Sometimes, preferable more often than not, it's just a wondrous thing to sit back and take it all in, with nary a thought of what's next on the menu..

 

Just checked out your speakers and amp - yep, makes sense that it's "so joy-inducing and fulfilling"; the amplifier is extremely comfortable driving these speakers to any desired volume levels ... you would have to go to great lengths, and expense, to do better than what this combination would give.

 

[sandyk]

16 minutes ago, fas42 said:

.. so a quick way there is, build a PS that can deliver to a 1000W unit, and instead put it into the 50W amp - and you mostly likely will be well ahead 😉.

 That's silly Frank.

1. It would be quite costly, and offer very little benefit , even if you pushed it to way higher than typical domestic levels which have already been shown to be quite low

2. It would be way too bulky to fit into a typical 50/100W Power Amplifier case , so you are looking at much more expensive metalwork as well.