Old but evergreen argument, class AB vs D!

[Cutaway]

interesting responses, i guess i'm just use to setting a small gain overlap of usually 3db on mids and highs and 5-7 db on subs... I first learned about this concept way back in the day when i was doing one of the MECP certs (different shops and manufactures i worked for required these) and have just continued doing it throughout the years. I am learning there are a lot of purest on this board which is great because your post cause me to rethink and question my self.

[geolemon]

interesting responses, i guess i'm just use to setting a small gain overlap of usually 3db on mids and highs and 5-7 db on subs... I first learned about this concept way back in the day when i was doing one of the MECP certs (different shops and manufactures i worked for required these) and have just continued doing it throughout the years. I am learning there are a lot of purest on this board which is great because your post cause me to rethink and question my self.

Don't think in terms of "purist vs non-purist", think in terms of "risk vs reckless".

If it "used to be" that class D was universally inferior to class A/B, and "today" there are designs and techniques that allow class D to sound just as good as class A/B, it's still risky and reckless to assume "all Class D amps sound as good as Class A/B". For sure there's going to be some of the old designs still out there - especially if taking the additional risk on some cheap, no-name brand.

The more risk-averse people will simply stick with designs and architectures that they know will work / sound good / etc.
That's not necessarily "purist".

It's always good to heed those people's concerns as warnings - things that are risks, that you need to actively mitigate by shopping wisely, specifically ensuring those negatives do NOT exist in what you want to purchase.

[geolemon]

"There was already the debate about sound quality theoretically decreasing from the digital nature of CD audio (pixellating the previously purely analog curves),"
^^That particular argument has always been total bull....Anyone that has ever listened to any record or cassette that was older than brand new knows those formats deteriorate so fast that there is no argument at all.
Regarding your curiosity about class D amps being just as good as old class A/B amps, they absolutely are (I'm 48, so I remember). The only downside is that the super small amps simply don't have room for a lot of capacitors, so they may not have the same dynamic response, an external capacitor could make up for that. Honestly, though, I haven't noticed any sort of deficiencies at all. I'm using JL Audio XD 400/4's, they're quite nice.

It's not at all BS, unless you are misconstruing this as some simpleton generalization about all digital media.
It's absolutely FACT that even the very best digital encoding will not/can not contain all the detail of an analog recording.

The best analogy that I recall for this is a fractal. That's one of those self-repeating images, that repeats infinitely. You could keep zooming in infinitely, and you'd see the pattern still repeat.
To some degree, that's an analog recording. There's practical limits on the actual recording equipment, but we'll get back to that.

If you took a digital photo of that fractal - even with the best digital camera ever - and then zoomed into it - you wouldn't have that infinite zoom capability You'd have what looked exactly like that fractal from a distance, looking at that photo - but as you zoomed in, you'd start to get the blur and pixelazation. All the detail would NOT be there. It's just not possible.

Same with converting an audio signal. Like it or not, an analog signal is a complex waveform that's infinitely smooth - and yes, that factors in the distortions and everything else preserved in the master recording. It's WHY the recording process is so important - what's captured there is locked in stone. But you can pull that analog signal up on an oscilliscope and zoom all you like- you won't ever get to a point where the waveform is pixelated. That is the beauty of analog.

When you encode that waveform, even to CD quality, you do get that pixelization - there is a decibel floor where the subtleties and details ARE lost, inherent in the recording process. The fact that SACD and competing formats exist was entirely to pursue a better quality than standard CD encoding.

Sure - if you are listening on a pair of Bluetooth Apple ear-dongles, or in a stock car, or on a bluetooth speaker in the basement - the quality of your reproduction gear won't be up to par to hear that. CD resolution was picked because it was a compromise, it was a "90% of people will NEVER be able to hear the difference!"
...but take a trip to the high-end audio section of CES some day. Some of the multi hundred-thousand dollar vendor setups in those rooms in the Venetian are set up with both analog and digital media as inputs (though the majority are analog only! $20k-$30K turntables as sources, specifically to demonstrate that high-end audio gear IS capable of reproducing all the detail in the recording!)

And the same goes for recordings - there ARE high-end recording studios, who CAN create master recordings at a level of detail that exceeds what a CD audio recording can reproduce. The fact that there's also guys with basement multi-track digital recorders making garage band and live recordings that don't contain that level of quality- that doesn't incriminate a recording format.

And it only gets worse from there...
MP3s (and similar) can be all over the board. If you couldn't hear the terrible quality of most people's Limewire-sourced MP3's back in the day, then I can't even imagine how terrible your playback gear was... All those digital formats started with already-encoded CD tracks, re-encoded and compressed them into MP3 or OGG or similar, at a bit-rate that is inherently defining the pixelation effect. You can't get around it.

And that's why it's similar to this class D argument...
Sure, it MAY be possible today to buy a high-end class D amp that has a switching power supply that makes absolutely perfect square waves, and they align so perfectly there's no overlap and no gap...
...but it's still possible to buy a lesser-than-high-end class D amp that's just intended for subwoofer use,with all the issues inherent in the old-school, price-pushing, power-above-quality class D amps that we started seeing way back when.

Not all class D is the same, same as not all digital audio is the same. It's definitely not a BS statement.

[Cutaway]

I don't run my amps into clipping...... but we generally don't listen to music with our amps constantly clipping.

Just curious what O Scope you're using to verify this? I'm not being a smart arse, I'm asking because I'm trying to find options for a have held o Scope
TIA

[ckirocz28]

It's not at all BS, unless you are misconstruing this as some simpleton generalization about all digital media.
It's absolutely FACT that even the very best digital encoding will not/can not contain all the detail of an analog recording.

The best analogy that I recall for this is a fractal. That's one of those self-repeating images, that repeats infinitely. You could keep zooming in infinitely, and you'd see the pattern still repeat.
To some degree, that's an analog recording. There's practical limits on the actual recording equipment, but we'll get back to that.

If you took a digital photo of that fractal - even with the best digital camera ever - and then zoomed into it - you wouldn't have that infinite zoom capability You'd have what looked exactly like that fractal from a distance, looking at that photo - but as you zoomed in, you'd start to get the blur and pixelazation. All the detail would NOT be there. It's just not possible.

Same with converting an audio signal. Like it or not, an analog signal is a complex waveform that's infinitely smooth - and yes, that factors in the distortions and everything else preserved in the master recording. It's WHY the recording process is so important - what's captured there is locked in stone. But you can pull that analog signal up on an oscilliscope and zoom all you like- you won't ever get to a point where the waveform is pixelated. That is the beauty of analog.

When you encode that waveform, even to CD quality, you do get that pixelization - there is a decibel floor where the subtleties and details ARE lost, inherent in the recording process. The fact that SACD and competing formats exist was entirely to pursue a better quality than standard CD encoding.

Sure - if you are listening on a pair of Bluetooth Apple ear-dongles, or in a stock car, or on a bluetooth speaker in the basement - the quality of your reproduction gear won't be up to par to hear that. CD resolution was picked because it was a compromise, it was a "90% of people will NEVER be able to hear the difference!"
...but take a trip to the high-end audio section of CES some day. Some of the multi hundred-thousand dollar vendor setups in those rooms in the Venetian are set up with both analog and digital media as inputs (though the majority are analog only! $20k-$30K turntables as sources, specifically to demonstrate that high-end audio gear IS capable of reproducing all the detail in the recording!)

And the same goes for recordings - there ARE high-end recording studios, who CAN create master recordings at a level of detail that exceeds what a CD audio recording can reproduce. The fact that there's also guys with basement multi-track digital recorders making garage band and live recordings that don't contain that level of quality- that doesn't incriminate a recording format.

And it only gets worse from there...
MP3s (and similar) can be all over the board. If you couldn't hear the terrible quality of most people's Limewire-sourced MP3's back in the day, then I can't even imagine how terrible your playback gear was... All those digital formats started with already-encoded CD tracks, re-encoded and compressed them into MP3 or OGG or similar, at a bit-rate that is inherently defining the pixelation effect. You can't get around it.

And that's why it's similar to this class D argument...
Sure, it MAY be possible today to buy a high-end class D amp that has a switching power supply that makes absolutely perfect square waves, and they align so perfectly there's no overlap and no gap...
...but it's still possible to buy a lesser-than-high-end class D amp that's just intended for subwoofer use,with all the issues inherent in the old-school, price-pushing, power-above-quality class D amps that we started seeing way back when.

Not all class D is the same, same as not all digital audio is the same. It's definitely not a BS statement.

I didn't mean to offend the $30,000 turntable buying vinyl purist in you. The ideal recording format would be analog, but without the susceptability to dust, scratches, wear, stray magnetic fields, spilled drinks, cigarette smoke, and oil vapor, because our cars aren't clean rooms. Digital media, while imperfect, provides a solution, a VERY good solution.
As for the class D argument, I also prefer class A/B, but I can't run 4 370 amp alternators and I got tired of burning myself on amplifiers 20 years ago. Again, new technology provides a VERY good solution, assuming you buy good quality class D amps. I'd say mid-level or higher class D's from reputable manufacturers are imperceptibly different from class A/B amps.

[ckirocz28]

Just curious what O Scope you're using to verify this? I'm not being a smart arse, I'm asking because I'm trying to find options for a have held o Scope
TIA

I've got the 1.0 version of this
https://m.liumytools.com/LIUMY-Oscil...ight-p-28.html
It's not good for much other than detecting clipping and basic multimeter functions, but I didn't expect any more than that.

[geolemon]

I didn't mean to offend the $30,000 turntable buying vinyl purist in you. The ideal recording format would be analog, but without the susceptability to dust, scratches, wear, stray magnetic fields, spilled drinks, cigarette smoke, and oil vapor, because our cars aren't clean rooms. Digital media, while imperfect, provides a solution, a VERY good solution.
As for the class D argument, I also prefer class A/B, but I can't run 4 370 amp alternators and I got tired of burning myself on amplifiers 20 years ago. Again, new technology provides a VERY good solution, assuming you buy good quality class D amps. I'd say mid-level or higher class D's from reputable manufacturers are imperceptibly different from class A/B amps.

Haha, well yes...
But seriously, offense has nothing to do with anything. It's tempting to project today's state of 'Murica "all that matters is my emotional reaction!" into an objective discussion... let's keep forums free of that kind of insanity.

I happen to be on the side that believes in science and engineering... and the view from this side of the fence is that people who feel emotionally and religiously entitled to their science-denial and alternative-facts-belief are all crazy people, including those offended outbursts against fact-checkers (that includes car audio) who are simply saying "well... no." If for some reason you have ME grouped in with those emotional wet paper sacks of human beings, then sure - I'm offended.

Trust me, I'm a digital music user - I'm just cautioning against making generalizations. We unfortunately ARE living in an ever-increasingly-simpleton world (or at least country), it's like Idiocracy come 490 years early - if you can't tweet it out as a generalization, there's a whole generation of people who don't have the patience to dig deeper to actually understand nuance.

And when you lose nuance, detail, the pursuit of pushing engineering, and "everyone is entitled to be an expert!" - then you lose integrity, and quality, and in fact the very point of even upgrading your factory system at all. "Good enough!" design leads in the wrong direction.

As I mentioned earlier, that already has contributed to the erosion of the whole car audio industry - so it's good to see some engineers working to push class D quality UP!

But you can still see that we're in a new world - if you can't order it on Amazon from a tweet you saw of some guy you don't know who probably has his first system and a post of his Skar subwoofer simply MUST be the best thing EVAR (what is anecdotal fallacy anyway?) and put up your own post asking how to wire up this dual 2 ohm DVC sub to your 2 ohm stable amp you bought because some other random person...
You get the idea. That's a real thing now.

So for sure - if I see comments on a thread where someone is trying to diminish a complex topic into a generalization - it's time to mention the reasons the generalization may be tempting, but is a road filled with potholes.

Hoping these forums stay objective and REAL.