It's clipping time

I already know my NeoMini DAC (strangely) clips when connected to the television. While cygig did mention that the NeoMini clips when driving his Triple-Fi, I never expected it to clip when driving a receiver.

And so I totally agree with his conclusion in his review of the NeoMini, because no matter how good the sound may be, if it clips it's gotta be a bad sound.

And that's what I'm experiencing with my new test set-up: Zhaolu D3, OPA627 op-amp with the following output stage bypassed, connected to Alessandro MS-1.

It clips obviously when volume is near the max. Even with the volume reduced to less than half, although it sounds much better, there are still traces of it clipping when the movement gets tough.

So that's what clipping (a bit of) sounds like. So that's what's been contributing to the noise in my Zhaolu D3, NeoMini, PSP, soundcard etc. So that's what's making the Cowon D2 sound so good. It's all about voltage and current swing. More correctly it's voltage swing and transient current supply, but they're related.

Lets see what happens in a few paint jobs:This is a wave, yea you know it.This is what happens with slew rate (voltage swing) is not enough, with the original wave in black and the alterations in blue.

On a square wave, it would make it look like a trapezium. Somebody once told me that it makes a sine wave look more like sawtooth, which suggests a faster drop than a rise, else it would look like a triangle if both are equal. But I'm no engineer and don't know how op-amps perform in real-life situations and the explanation for that.

How about some problem with current this time -It clips. Yes, insufficient current output causes clipping. This is because while the amp increases the voltage, it also increases current drawn by the circuit (V=RI), and when the current supplied cannot keep up, it causes a voltage drop, like in an unregulated or underpowered power supply, until the voltage drops to the point where the current can keep up. Which means the voltage cannot increase past that when the maximum current is reached.

While I know some people would not be able to understand this right away, it's basics to the pros. Right yan?Although in real life it'd be a bit like this, with rounded edges. There's no exact in everything, especially when it comes to electrical specs and overdriving. The above picture shows soft-clipping when it the corners are rounded, but depending on how much voltage swing or how early it clips, you'll still get a pretty hard clip most of the time when it happens. Or actually, when you actually notice the clipping it's a pretty hard clip already; soft-clipping gets passed off as distortion. I'm not confident enough to say what exactly it sounds like, maybe next time after I decide to hear more of it.

BTW the soft-clipping function on some amps/AVRs make the soft-clipping happens early when a certain voltage is reached so that it can round the corners more.

So if an amp cannot handle enough current or voltage swing (when the volume is too high), get another amp to do it. So now I totally understand the use of a preamp, other than to change the sound.

And now I totally understand the use of a second op-amp stage in the Zhaolu too (as well as many high-end products). Because the OPA627 alone feels a little grainy and not enough bass punch when connected to the Yulong. And connected to the MS-1, the above flaws are greater.

But still, it sounds much nicer than with the LT1028 or the JRC4556 pre-amp.

One thing still puzzles me though - why are clipping problems happening with the NeoMini when driving a receiver in a TV instead of headphones? And why is it happening to the OPA627 too when driving the Yulong? Aren't receivers supposed to have high resistance along the path?

Or perhaps, even with these good figures, one still cannot get the best sound. Audio is scary.

Really, one cannot base his beliefs on his limited knowledge. Because the real thing is different from whatever "facts" that he might know. Now that this kind of thing has happened to me I'll believe more in the EXPLAINABLE audio stuff. I'll still not believe that putting extra caps along the signal path will "improve" the sound, because it's explanable that it CHANGES the sound, but not IMPROVE, and definitely not make the source into any higher-current one.

BTW I might as well talk about the myth of speakers being killed by clipping, since I now have a picture that shows clipping and the original waveform.

The explanation is that clipping kills speaker by providing too much "DC" current, thereby transforming the speaker from a reactive load into a resistive load, heating up the coils and killing the speaker in the process.

But if you look at the graph, you can tell that the one-direction current over time is actually smaller.

Basically, even when there's clipping, the voltage still fluctuates between positive and negative, so the AC (as well as its frequency) is still the same.

What about the reactive load explanation, that energy is returned to the source in AC? If you look at where the clipping takes place, the green line shows the DC component while the black line shows the AC part. Yea, the AC is returned to the source, but the DC part is still the same.

Logically speaking, the amp isn't powerful enough to magnetize the coil properly, let alone kill it.

BTW I've had my Zhaolu clip TOTALLY before, hence it shows that clipping does not kill, if the power isn't great enough. But if the power IS great enough, it's the power that kills anyway.

So under what kind of situation will clipping really kill speakers? (I think most of the time it's the amp that die first isn't it? And in the process take-out the speakers too.) The DC reasoning is acceptable to me, but I'll need to find a way to generate a long enough DC current to kill. It's known that pure tones of 10Hz can damage your speakers, so it supports the above reasoning and shows that it's possible.

Now, how about if we add slew rate into the picture? This is just a noob guess but please bear with me, I'm sure it would be interesting even if it's wrong.

Imagine a wave that's clipping. It needs to go down to the negative voltage but somehow the slew rate isn't fast enough so the voltage is still positive when the next rise occurs. So the DC is there for an ultimately long duration. The voice coil heats up and "boom".

However, in order to do that, your DC component still has to be relatively great. I know my subwoofer has a DC offset because when I switch on the power, the cone gets sucked in and it starts whining. But it isn't dead yet, so I can safely say that before the DC component gets high enough to kill your ears are killed first, because the sound is going to be f-king distorted.

What about those YouTube videos of people blowing up their speakers by connecting 5V or 12V to them? Do the maths, to a 4 ohm driver, applying 5V is V^2/R = 5^2/4 = 6W. With 12V it's 36W. 6W will kill over time, but imagine your CPU or gfx card's 36W, without a heatsink, in a sealed container. I cannot think of anything that would't blow up. BTW 6W in AC is already very loud, that's the maximum low-distortion volume of a Tripath TA2024 T-Amp. As well as many PC speakers at full-blast without clipping (full-blast meaning with a loud enough input source).

So DC kills. But power kills also.

Don't feel like upgrading com anymore...

There was a time when I was constantly dissatisfied with my com for being too slow and unable to run many of the games that I wanted.

But now, after a few years, I've always been using my same computer without thinking of an upgrade.

Because, there just isn't anything to upgrade to.

Because, I seldom play new, hardcore 3D games anymore. (save for the time when I bought a second-hand x1950pro, but I only had it for a short while before selling)

Because, my com is fast enough for my needs.

Have I... become more matured? I seldom see the older generation upgrading their coms, as long as it's usable it's good enough. My friends who don't play games (well, the demanding ones) do not upgrade their coms either.

And now, without the crave to play newer, graphics-demanding games, I have no crave to upgrade my com either.

I'm spending much more in audio now though.

And regarding the maturing part, I'm still watching Anime, so I still got some ways to go. But at least they're better than the soap operas that our dear country is constantly producing "lately" (since at least a few years ago or since time existed).

How wrong information spreads on the internet:

(you can replace internet with forums, works the same way)

Initially, nobody knows about a product to comment on it.

And then...

1) Noob somehow gets some info and comments on it. He may own the product, used it for a split second, seen somebody use it for a split second, or heard info about it from some obscure source, excluding the internet, including his brain or some voice from the sky. (Note: Noob will always give the wrong info, a pro knows how to review and judge a product as well as know a lot of and analyze information)

2) Nobody believes or cares a hoot about the noob or what he says. Except for other noobs, and noobs who like to act pro.

3) Other noobs ask about same or related topic, Act-pro answers using information gotten from First-noob.

4) More people believe in it, because most people cannot differentiate between Act-pros and pros, in fact Act-pros appear more pro and pros usually don't bother with noob questions.

5) When this topic is brought up again, people respond with what they know i.e. information originally gotten from First-noob, but this time everybody says the same thing, and it eventually becomes a fact.

The beauty of this is when you ask for hard evidence, people either divert, ignore, give useless answers (noob answers, because they only know that much), and/or turn aggressive.

Audio... from a non-audiophile perspective

Check this out:

(Posts from a thread on Omega Claro Halo on a certain forum)

"All soundcards have amplifers, or else the volume would be so low you couldn't hear anything. It's marketing."

"btw- a strong sound card (x-fi, audigy, some nicer cmedia cards) puts out as about as much power as a portable amp. an x-fi does for sure. keep that in mind b4 buying an a cmoy/go-vibe/ppav2 to 'complement' your x-fi. instead save up and get a nicer amp."

"it has op-amps... big deal"

I wouldn't say they are noobs, just not at that stage (of audio) yet. I was once like them too. The difference between a beginner and a noob is that a noob is one who does not listen to others and/or imparts their wrong knowledge as facts to others, both due to huge ego, often resulting in them spending extra for inferior products (due to marketing), misguiding others, and starting flame wars.

I wouldn't say that I'm not a beginner or a noob to some extent too. Well, I do hold some of my own beliefs and impart them, but at least I listen to opinions and learn. :P

They are at most commenting their opinions or some facts that are, in fact, correct and rational (for their stage), and not challenging the knowledge of the more experienced ones.

It's only when you get to the later stages, when you fully understand the stages of audio reproduction, then you'll understand where and why op-amps are used, and that sound cards may not provide enough power for your headphones. Those without a seperate amp chip at least. Then there's also quality of sound.

Well, when you get to the point where cables matter, all these things will be easily acceptable, at least they are explainable and measurable. Cables too are, but much harder.

Ironically, the last guy has Auzen X-Fi Prelude > Soloz Audio Reference IC > TCA Gizmo > Onix Reference 1 MKII speakers for his setup. The Prelude itself has OPA2134 and LM4562, both decent op-amps. For him to make that kind of statement with his setup is enough to call him a noob, don't cha think?

Random noob find of the day:

"So, back to audio... I'm very happy with 16 bits of resolution, although the sampling at 44.1 K lacks... Really that's only about 3 samples at 15k Hertz. It amazes me that cymbals actually sound like cymbals at all. They did an amazing job with the technology they had at the time.

Now the problem is the audio sampling will be so fast and so high a resolution, it will pick up everything, and that also means allot of noise too.

Controlling all that noise that these new formats will be capable of hearing / recording will be VERY challenging!

I myself will step up to the 24 Bit, 192K soon, as that seems to be very popular, but really it is obsolete already.

With computers anyone can pretty much come up with any sampling rate and resolution, as long as you can record the data.

Video recorders for instance, go super fast compared to audio, why not use a digital video recorder to record music ???

Maybe 4 Million samples at 64 bits is too high, LOL."

This guy has no understanding of how audio reproduction and our ears work.

44.1k sampling rate actually translates into 20.5khz maximum frequency, because you need 2 samples, up and down, to create a wave.

Which is not a problem, since we can only hear that high anyway.

"3 samples at 15k Hertz", what the hell is he talking about? That we can have three 15khz sounds at 44.1khz?

When you have 2 1khz sound sources, what you get isn't a 2khz waveform, but it could be 1khz, 2khz, or requiring even higher depending on the phase.

Fortunately, all this sound will combine into a single complex waveform, which is all we need to hear and record.

However, however complex the resultant waveform is, we will still only hear frequencies that are below 20khz. Even if the waveform has e.g. 40khz waves, those will be inaudible.

So there's nothing wrong with the 44.1 sampling rate, at all, except perhaps a few of us with musician ears can hear past 20.5khz, but few humans will ever reach 24khz (for 48khz sampling frequency). The extra hertz at 96/192khz will be useful in more carefully reproducing the complex waveform which is the result of interactions between instruments, but you would be able to sense less distortion at most instead of actually hearing something missing or extra.

Next, video and audio recording are two different things. The most major difference - sampling rate. With video, 600fps is possible with high-speed cameras. Compare it to the 44.1khz sampling rate, or 44100 samples per second.

If you can find any video sensor that can handle 44100khz let me know, you should patent it.

And the saddest part is that this guy is the owner of an audio forum.

Random fact of the day: The sound quality of the DAC/soundcard isn't solely decided by the DAC chip used

The DAC chip is only a few bucks expensive at most, versus the few times more you'd be spending on capacitors and such other components, the op-amp can easily out-cost the DAC by a few times alone.

So why didn't the manufacturors just plug in a better chip, since it's so cheap? Reason because a better DAC chip also requires better implementation to bring out its performance, and not all chips will work in all circuits. For example, with a LM4562 in the CS4398 Zhaolu D2.5C, users have complained of a wierd treble that's somewhat harsh. Even though both the LM4562 and CS4398 are good chips themselves. And with the LM4562 in the Zero, a fellow forum member feels that the sound is too dark, way contrary to the bright and dynamic sound I experienced with the Zhaolu as well as Mini3. (I have some possible reasons to explain this, that may turn-off Zero owners)

Anyway, the bottom line is that the DAC chip doesn't solely decide the sound quality. Hence it irks me when I see advertisements or supporters basing their facts solely on the DAC chip used. For example, "something uses the something chip, which is the upgraded version of a something something used in a something hi-end CDP". C'mon, like I said, it's only a few bucks at most, how would spending a few bucks more make something high-end? If that few bucks can make your something match up against a hi-end something, then I'd rather make my own something which will even be higher end, since it would cost only another few bucks extra.

If you're still not convinced, Creative's sound cards use the CS4398 which is also used in the hi-end somethings. Yet they sound like... Creative sound cards. (Please come up with the conclusion yourself)

When people don't even have common-sense... let alone specific knowledge

ADD: It would be better if you see the TOTALLY UNRELATED ad linked below first

From a gaming speaker* ad (edited):

- Downward firing design creates an omnidirectional effect
- Sound waves originate from the same source
- Omnidirectional sound stage - by deliver sound in all directions, sweet spot is enlarged
- Special amplifier matches input power with power demand

Ok, here goes:

- The argument against normal, forward-firing speakers is that sound bounces off the wall and reaches the listening in different paths and time, also known in the normal world as echo
- By using a speaker that fires in all directions, wouldn't the sound bounce off in much more directions before reaching the listener?
- Then how is it supposed to help with the situation? It actually worsens it don't you think?

Didn't even think of using general knowledge before writing this one.

Now, onto the more technical ones:

- It actually sounds better because of the reflected sound. Or more technically it's called off-axis sound (as opposed to on-axis sound/coming straight from the driver), but I don't like to use technical jargons that make the writer seem more knowledgable to hide his lack of knowledge while confusing newcomers, when an easy layman term can mean the same thing and is much understood my everyone. Reflected sound tends to have more feeling of space as well as sound more natural and less harsh, with the downside of less accuracy and dependency on room acoustics.
- Reflected sound is so useful because the effects are nice sounding, that many speakers, more notably karaoke systems, and especially Bose systems, have drivers dedicated to firing sideways or even backwards. As mentioned, accuracy is compromised, but the benefits outweigh the costs.

Onto the next point:

- The "sweet spot" is greater because , ironically, of the refracted sound also. Think of two beams of light that are slightly spreading out. You have to stand in the middle to get both beams. Now think of two light bulbs. You can stand anywhere to get light from both sources. However, it'd be harder to ensure that the amount and distance from both light bulbs are equal when you factor in the reflection, that you won't even know where is the best spot, if any.

And the one after:

- Special amplifier matches input power with power demand

That's just a fuking class-H amp. It's nothing special, and no they (the company owning the ad) didn't invent it.

Is it good? Not sure, it's good if you need a huge amount of power and still stay efficient at low loads, but with a class-D amp typically found in these kind of speakers without a huge heatsink at the back, why would you even care about efficiency and insufficient power? And with another switched-mode power supply for the tracking rails that's basically useless at low volumes, *cough*.

BTW, Razor has a TOTALLY UNRELATED product here:
http://www2.razerzone.com/images/mako/mako-tech.php

*Gaming speaker suggests a system that's only good for gaming and nothing else - music, movies, serious sound production of any form

I for one don't believe in speakers being designed for anything, like 25% gaming, 50% movies, 30% music, and -5% Windows error messages. Good speakers faithfully reproduce anything that's thrown at them. If speakers are said to be "designed for something", more often than not it means the following:

Gaming - Huge amount of bass, nothing else
Movies - Huge amount of bass, huge amount of highs, nothing else
Music - Warmth and space, usually reflects a boost in the midrange, some boost in the mid-bass and usually insufficient deep-bass, reduced highs for less harsh
Strings - midtones and overwhelming bass (for the double-bass), some harshness in the highs for the violin's sonic character
Guitar (acoustic) - very good highs response (for the plucking of strings), very linear mid-bass response - so far I see that, on good systems, guitars really shine
Rock - Good dynamics, good bass, good highs, no detail required
Jazz - Good deep-bass, linear bass, good mids, good highs - an upgrade from guitar

And my favourite:

Vocals - Lots of mids without anything at the ends of the frequency spectrum (as you can see, that's the same sound signature as a cheapo speaker, apart from being clearer)

So, what kind of speakers do you have, and what do you like?

Ignorance isn't always bliss: Part 2

Talk about real noobness, this one transcends audio.

Because of the severity of the case I'm going to quote it in full:

"Selling the above. The Zero DAC was purchased from an MO around May this year, so no local warranty. 100% functionality, no cosmetic flaws. Will also include the USB to Optical converter (you will need this for PC use as there is no USB input on the Zero).

The OPA627 (OPA627APG4, to be exact) op-amp was purchased from Farnell on 5 Sep 08, so be assured that this is the real thing. I will pass you the actual receipt of the purchase. Comes together with the 8-pin adaptor that was purchased separately, so just plug into the DAC and enjoy the sweet music. Try buying the op-amp and the adaptor separately - it will definitely cost you more than $70."

Erm, yea, did anybody tell you that Farnell likes to chop carrot on certain products? Especially when it comes to higher-end audio products, which they do not have a big selection of.

He should've gotten the Zero+ DAC which adds the same thing for only an extra $50 more at Ja**n. But that's still giving $$$ to Ja**n, because in China, the upgrade can be had for 100rmb or less. That's less than 20 dollars. Cos electronics are cheap there, and things are priced at what they are worth, unlike in other areas of the world especially SG, US, Europe, Japan, Australia blah blah, where you can spend lots of money to buy a cheap product, just because of marketing and hype.

And, if I'm going to spend $70 upgrading IC op-amps, I'd rather spend ~$30 to get a discreet op-amp from audio-gd. And that's for two channels. And that's gonna pwn your ass because on the surface (or to audio noobs), discreet op-amps MUST be better than integrated circuit ones.

BTW, if anyone wants the op-amp-upgraded Zero, he's selling at $220. Or you can camp at echoloft for much better deals. Zhaolu D3... hmm... tempting... but I got my D2.5A already and it uses the AD chip which has more space feeling, and I might need the headamp. But the D3 uses the more expensive CS4398 and is priced two times as much, but the 2nd-hand price isn't two times as much...

Random observations of the day:

I can actually still hear some vocals from my sub, just the sub alone, no satellites.

And it feels kind of cool.

So my subwoofer has a high x-over. That makes it a lousy sub.

And it rumbles a lot. Not a good sub.

And it whines a lot from the DC component that's somehow in my AC mains.

Fk good quality SG power. And fk the noobs that say we don't need a power conditioner in SG.

Random thought of the day...

"If only they can make a plastic that has the same sonic properties as wood. Then we wouldn't have to bother about the wood rotting and coming apart. And it looks cooler, too."

This is the first random thought of the day to make it onto the blog.

Because whenever I have random thoughts I'm usually outside. Then when I reach home I'll forget about it totally. And why I seldom have random thoughts at home is because I'm seldom bored at home. Just shows how interesting my life is.

This thought came about while I'm fixing up my re-fused sub.

More audio noob-dity, and audio myths/antimyths

This should go into my upcoming, extra long post on audio myths and antimyths, but decided to make it on its own since it is relatively rare, high-level (in terms on how much money/hearing you need to spend to reach this stage), and significant.

Some guy from a certain forum (pls don't be offended) said this:

"1) THERE IS NO NEED FOR A POWER CONDITIONER IN SINGAPORE"

I forgot whether he had caps. But I can't access the forum at home to verify.

There is no need for a power conditioner in Singapore, because why? The usual answer, because our power supply is clean enough?

Well, firstly, clean is not equal to stable. Our power supply is relatively stable, but not clean. Actually, with all the modern equipment dumping EFI into the mains lines, a city's power is gonna be more noisy than the countryside.

If your transformer or speakers whine, and if it's not due to a faulty equipment, high chances that it's the power.

If in my house, I had 3 sets of amp/speakers that whine, whine more in the night, and whine more when the light in my brother's room is on, there is no way a power conditioner of some sort wouldn't help.

And, is this significant? If your speakers, no matter how good, are constantly buzzing you would want to do something about it isn't it? Like a totally stupid and irritating thing called tinnitus that doesn't affect daily functionality but degrades the listening experiance, not to mention it is totally loud when everything else is quiet.

(To be continued...?)