Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Build Your Own Professional-Grade Audio Amp on the Sort-Of Cheap

spectrum.ieee.org

Post reply on HN
Print view View original

161–170 of 270 posts

Re: Build Your Own Professional-Grade Audio Amp on the Sort-Of Cheap

#161

Post by stinos »

willtim wrote: post #36
fermienrico wrote: post #16

It is refreshing to see these types of articles. Of all disciplines of human interests and hobbies, Audiophiles are one of the most stubborn, misinformed, anecdotal and delusional bunch. Of course I am generalizing, but every time I engage in a discussion about audio quality, it is a losing battle. Not because of lack of data or supporting evidence, but because of the fundamental dissent for data driven arguments. Yo…

Your generalisation is unfair. Most Audiophiles just want to listen to music the way the artists intended. This is not easy in a industry where colouring the sound is even celebrated, e.g. 'Beats by Dre'. I recently tried the latest noise cancelling headphones by Sony (1000XM3). The noise cancelling was excellent, but the bass was +5db overblown, boomy and drowned out most of the mids, the treble was dark to hide the…

The noise cancelling was excellent, but the bass was +5db overblown, boomy and drowned out most of the mids, the treble was dark to hide the NC hiss

Had pretty much the exact same experience with some noise-cancelling in-ear pair of Bose. I was actually amazed at how good the noise cancelling was, but sound reproduction even in absence of any outside noise was very sub-par. Now I can't imagine the engineers didn't measure this thing, so I'm assuming it was done on purpose, maybe aimed for pop music or so?

Re: Build Your Own Professional-Grade Audio Amp on the Sort-Of Cheap

#162

Post by tobyhinloopen »

Karunamon wrote: post #44
fermienrico wrote: post #16

It is refreshing to see these types of articles. Of all disciplines of human interests and hobbies, Audiophiles are one of the most stubborn, misinformed, anecdotal and delusional bunch. Of course I am generalizing, but every time I engage in a discussion about audio quality, it is a losing battle. Not because of lack of data or supporting evidence, but because of the fundamental dissent for data driven arguments. Yo…

Of course they’re anecdotal - listening to music is a subjective experience. If someone really thinks their music sounds better after adding $100 cable lifters and taping $50 bags of rocks to their $10,000 system, they are automatically correct . Their ears, their hobby. It would be like saying that something can’t work because it’s a placebo - even if all they’re getting is a sugar pill, if the symptoms went away, t…

I have $2000 speakers and I use a $60 2nd-hand amp from 1999 and a $20 bluetooth dac with them. Audiophiles hate me. Bluetooth is the greatest sin, apparently.

I have AB tested my amp with newer models and while there was a difference, it was very minor and not worth upgrading IMO

Re: Build Your Own Professional-Grade Audio Amp on the Sort-Of Cheap

#163

Post by setquk »

S_A_P wrote: post #123

Audiophilia is a study in contradiction. The ask is a flat "uncolored" accurate sound. The gear that sells for ridiculous prices is usually tube gear with limited bandwidth and makes ~15 watts at 5-10% (admittedly usually even order harmonic) thd. Hardly uncolored. That said, and Ive mentioned this before on HN. My (now late) uncle had a bunch of audiophile friends in Dallas. He hung around folks who had spent upward…

I’ve heard such things. Two points to note:

1. Decent monitor headphones or speakers sound the same. That’s under $500. Even some Sennheiser HD25’s are literally up there.

2. The equipment used to record such music cost less and was lower quality. Adding $500k doesn’t add anything because there isn’t anything there.

Then again I have no problem with people who spend $500k on audio kit. That’s up to them. If it makes them feel good buying something in that range then fair play to them. It’s mostly just art.

What I object to is little bags of stones wrapped around cables, magic boxes which absorb non physical entities in the room and directional cables. Woo and such needs to be taken down.

Re: Build Your Own Professional-Grade Audio Amp on the Sort-Of Cheap

#164

Post by quakenul »

sjwright wrote: post #143
S_A_P wrote: post #123

Audiophilia is a study in contradiction. The ask is a flat "uncolored" accurate sound. The gear that sells for ridiculous prices is usually tube gear with limited bandwidth and makes ~15 watts at 5-10% (admittedly usually even order harmonic) thd. Hardly uncolored. That said, and Ive mentioned this before on HN. My (now late) uncle had a bunch of audiophile friends in Dallas. He hung around folks who had spent upward…

The three critical paths for high end sound reproduction are: loudspeakers, speaker placement, room acoustics. Of course all parts of sound reproduction matter, but those three are the ones that affect real systems in practice. Most other factors are rarely an issue and/or inferior parts have a much lower magnitude of impact on sound quality. Sufficiently good source material (256kbps AAC or better) is widely availab…

Not in that order though, unfortunately: Unless you are using really shitty speakers, room acoustics trumps everything else pretty quickly. For anyone who has never listened to music in a well treated environment I found https://youtu.be/dB8H0HFMylo?t=355 to be pretty eye opening.

Re: Build Your Own Professional-Grade Audio Amp on the Sort-Of Cheap

#165

Post by ericdykstra »

rectang wrote: post #134
AceJohnny2 wrote: post #3

Earlier quoted context omitted.

Tangentially, the placebo effect is everywhere. If it can affect tasting (wine) and hearing (audiophile gear), I'm surprised not to have noticed its affect in discussing photography. Will "computational photography" (as touted in the latest iPhones) that alters photos based on criterion of perceived quality end up bringing these kind of inane discussions there too? Edit: Never mind, I didn't factor in all the argumen…

I made my living as a mastering engineer for two years... To do good work in mixing and mastering, it's important to study the human perceptual mechanism and its propensity for illusion, and it's also important to understand masking effects and how to amplify certain components long enough to tweak them before dialing them back to recede into the gestalt. It's also important to understand that in sound reproduction t…

This is pretty fascinating. I can't add to a discussion, but I would certainly read more about this if you have produced it somewhere.

I'm also curious, what made you leave your job as a mastering engineer?

Re: Build Your Own Professional-Grade Audio Amp on the Sort-Of Cheap

#166

Post by b1daly »

quakenul wrote: post #164
sjwright wrote: post #143

Earlier quoted context omitted.

The three critical paths for high end sound reproduction are: loudspeakers, speaker placement, room acoustics. Of course all parts of sound reproduction matter, but those three are the ones that affect real systems in practice. Most other factors are rarely an issue and/or inferior parts have a much lower magnitude of impact on sound quality. Sufficiently good source material (256kbps AAC or better) is widely availab…

Not in that order though, unfortunately: Unless you are using really shitty speakers, room acoustics trumps everything else pretty quickly. For anyone who has never listened to music in a well treated environment I found https://youtu.be/dB8H0HFMylo?t=355 to be pretty eye opening.

Even in well treated environment , speaker placement is critical. I’ve been working in pro audio 30 years and still surprised at how much moving speakers affects their performance.

Re: Build Your Own Professional-Grade Audio Amp on the Sort-Of Cheap

#167

Post by AnthonBerg »

scblock wrote: post #135
milesvp wrote: post #50

Earlier quoted context omitted.

I'm not convinced audio engineers are having that argument anymore (which is more the audience of IEEE). I get the impression from an engineer I know who's specialized in digital signal processing, and who's done a significant amount of analog work, that anyone who's still having some of these arguments doesn't understand some of the basic maths of the problem space. That basically, you can always digitally encode an…

Amplifier designers most certainly are. Class D has significant energy efficiency advantages, and significant sonic challenges. It’s taking an analog waveform, whether decoded by a DAC or starting as pure analog, and chopping it into a series of pulses (pulse width modulation). The amp is switching transistors on and off very quickly, rather than using them as a variable linear gain stage. It’s not the same as PCM en…

The thing is that transistors’ behvior is more linear and controlled when fully on or off rather than when used as continuously variable. Class-D can and does sound _amazing_ if built with good theoretical understanding. Check out Hypex amps designed by Dutch engineer Bruno Putzeys on strong control theoretical foundations.

Re: Build Your Own Professional-Grade Audio Amp on the Sort-Of Cheap

#168

Post by jabl »

WalterBright wrote: post #151
mrob wrote: post #42

It's bizarre how none of these chips seem to have a digital input. All my music is digital, and despite the modern rise of vinyl, I don't think that's unusual. If I want an amplifier like this then I'm forced to have a completely useless DAC/ADC pair degrading the signal quality. Does anybody know of an easily available class-D amplifier with digital input? You'd think that would be an obvious feature for a digital a…

All stereo components, except the amp connection to the speaker, should be ethernet. Turntable, CD player, cassette, pre-amp, everything. Then make it wifi. Just think, you could eliminate that awful rat's nest of cables. The sound quality would be better. You could locate components where-ever convenient. Each component could have a web browser interface. It'd be awesome.

https://en.wikipedia.org/wiki/Audio_Video_Bridging

Re: Build Your Own Professional-Grade Audio Amp on the Sort-Of Cheap

#169

Post by dejv »

vichu wrote: post #4

I don't know much when it comes to audio amp design, but this reminds me greatly of the O2 headphone amp[0] - that anecdotally a few of my friends have soldered for their personal use. [0] http://nwavguy.blogspot.com/2011/07/o2-headphone-amp.html

O2 is great and it is quite simple to build. There is even simpler amp called CMoy[1] which is simple enough to be first project for somebody just starting out.

I would start by taking look on some oss version[2] and order PCB from OSH Park[3]. I've built this version few years ago and it works well.

[1] https://tangentsoft.net/audio/cmoy/ [2] https://github.com/akafugu/cmoy [3] https://oshpark.com/shared_projects/dRKK4dgN

Re: Build Your Own Professional-Grade Audio Amp on the Sort-Of Cheap

#170

Post by scns »

sjwright wrote: post #143
S_A_P wrote: post #123

Audiophilia is a study in contradiction. The ask is a flat "uncolored" accurate sound. The gear that sells for ridiculous prices is usually tube gear with limited bandwidth and makes ~15 watts at 5-10% (admittedly usually even order harmonic) thd. Hardly uncolored. That said, and Ive mentioned this before on HN. My (now late) uncle had a bunch of audiophile friends in Dallas. He hung around folks who had spent upward…

The three critical paths for high end sound reproduction are: loudspeakers, speaker placement, room acoustics. Of course all parts of sound reproduction matter, but those three are the ones that affect real systems in practice. Most other factors are rarely an issue and/or inferior parts have a much lower magnitude of impact on sound quality. Sufficiently good source material (256kbps AAC or better) is widely availab…

The weakest "link" in the "audio-chain" (if you exclude the room) are passive speakers with distortion above 1%

The best speakers i heard to date are from a german company called Backes & Müller. Active crossovers, each speaker has its own poweramp and a sensor attached to the membrane. The signal of the sensor is fed back into a comparator which calculates the difference to the music signal, this is then used to force the speaker to follow the music signal exactly.

>On the basis of physical factors all drivers make mistakes, which one must accept in passive and uncontrolled systems. In contrast, all BM drivers are a part of active error correction systems.

>Active loudspeakers know no conduction loss, no impedance issues; have faultless crossover performance, exact phasing, an optimal amplifier-chassis ratio, more actual output stage power at their disposal, quicker impulse processing and higher dynamics. All of this produces active regulatory intelligence. A sensor system continuously compares and corrects the membrane movements with the actual music signal.

>B&M uses two types of negative feedback: inductive and capacitive. Intelligent electronic fuses ensure that the entire system is reliably shut down in the case of an impending overload. The BM electronic crossover splits the music signal into individual paths of respective frequency ranges and allocates these to their individual output stage. Every individual output stage drives to its respective driver, optimised for its frequency range.

from http://www.backesmueller.de/en/b-m-technology.html

Pricey and not DIY friendly, but you can pick them up used on ebay for "peanuts". W0as thinking about buying an BM8 (3-way) refurbished for 2800 Euros, BM10 (4-way) refurbished costs 10000 Euros, got a BM12 (5-way) used for 1400 Euros.

The company is now owned by http://ksaudio.com

Post reply on HN