Keith Anderson Posted August 18, 2013 Posted August 18, 2013 http://www.gspaudio.co.uk/blog/specs-or-music_post61.html Don't understand it all so anyone want to chip in what it all means
bzr Posted August 18, 2013 Posted August 18, 2013 That is his opinion. Perception has been proved otherwise.
betty boop Posted August 18, 2013 Posted August 18, 2013 might find this interesting too http://www.tnt-audio.com/edcorner/june13.html one thing is for sure. there is a lot of supposed hi-res...that is just upsampled 16bit in my opinion. not that there is anything wrong with 16bit in itself
Keith Anderson Posted August 18, 2013 Author Posted August 18, 2013 That is his opinion. Perception has been proved otherwise. Well of course it's his opinion. But how does perception prove anything?
Guest fordgtlover Posted August 18, 2013 Posted August 18, 2013 That is his opinion. Perception has been proved otherwise. Source?
emesbee Posted August 18, 2013 Posted August 18, 2013 I don't really follow the logic of what he's trying to say (I have no idea what slew rates are), but the article looks very much like an opinion piece. He seems to be claiming that the only difference between 16 bits and 24 bits is the signal to noise ratio, but is this really true? He doesn't provide any references to back up his claims.
hochopeper Posted August 18, 2013 Posted August 18, 2013 (edited) It is an opinion piece used to raise the importance of slew rate when purchasers of equipment come looking and are comparing specifications. Slew rate is just another way of representing bandwidth and excess slew rate isn't of much use when we can't hear high frequencies ... he says his designs can do 5x the audible range, so presumably up to ~100kHz. He's used a few half-truths and made a few logical jumps that are slightly skewing the conclusions he's come to, I don't have time to go through it and explain each of them, maybe someone else does? The bit depth and SNR allow some flexibility in the signal chain. 24bit can certainly get much better than the 120dB ceiling he suggests and he's correct the SNR of subsequent stages will normally be the limit on the SNR at output of the power amplifier. Edited August 18, 2013 by hochopeper 1
NeoG Posted August 18, 2013 Posted August 18, 2013 (edited) They're giving us bigger and bigger boxes to contain smaller and smaller things. I'm going to use this line. I like it. Don't understand it all so anyone want to chip in what it all means First paragraph poses a question Second suggests that extreme SNR is currently a buzzword, then implies that it is somewhat meaningless P3 - Poses a thought experiment - Why have more SNR in the audio format when you are really limited by your equipment P4, P5 - Suggests that with commonly found audio equipment the difference in SNR between 16 and 24 bit is negligible to irrelevant P6 - Audio woo GTFO P7-P13 - Directly attributes amplifier slew rate to musicality (dubiously at best), explains that musicality (slew rate) and low noise are mortal enemies and can't be in the same room together. They may have been married and divorced in another universe - who knows P14 - Perhaps counselling can get them to stand each others presence in moderation P15-P17 - An abundance of musicality (slew rate) is possible and gives those figures listed but sacrifices the noise floor P18-19 - By opting for higher musicality (slew rate), noise floor gets thrown out the door and there is no tangible benefit to the increased dynamic range of 24-bit. You can get the lower noise floor to match the DR of 24-bit by excessively limiting the slew rate and using steep filters - considered a no-no by the author of the article I don't really follow the logic of what he's trying to say (I have no idea what slew rates are) He seems to be claiming that the only difference between 16 bits and 24 bits is the signal to noise ratio, but is this really true? He doesn't provide any references to back up his claims. In audiophile terms, think of the slew rate as the amplifiers 'transient speed' If I may use simple resource based maths.. The article states that 24-bit has a DR of 120dB (or maybe that 120dB as commonly purported is an achievable target rather than 144dB), but most other sources state a DR of 144dB. I'm inclined to go with the general consensus. At these values, both 16-bit and 24-bit both have exactly 0.166 bits per dB, meaning the resolution of both should be equal. Given that information, 16-bit and 24-bit should sound equal when the DR is limited by something other than the source audio format Edited August 18, 2013 by NeoG
Phantom Posted August 18, 2013 Posted August 18, 2013 Just another audio writer with an opinion. How very rare.
hochopeper Posted August 18, 2013 Posted August 18, 2013 For clarity, I strongly disagree with the assertion that slew rate IS musicality.
ArthurDent Posted August 18, 2013 Posted August 18, 2013 Just another audio writer with an opinion. How very rare. Graham Slee isn't an audio writer, he builds stuff and has been doing so for a long time and is very well respected. 2
ArthurDent Posted August 18, 2013 Posted August 18, 2013 (edited) For clarity, I strongly disagree with the assertion that slew rate IS musicality. I think his assertion is that high slew rate isn't musicality and that chasing it and high S/N isn't the way to achieve it. Edited August 18, 2013 by KenTripp 1
CraigC Posted August 18, 2013 Posted August 18, 2013 Actually slew rate is the speed at which the device allows the the signal to change. I.e how fast the device can respond. It is measured in units of time. I'm not sure that bandwidth is involved.
NeoG Posted August 18, 2013 Posted August 18, 2013 Actually slew rate is the speed at which the device allows the the signal to change. I.e how fast the device can respond. It is measured in units of time. I'm not sure that bandwidth is involved. From what I have garnered on the subject, there is a relationship between bandwidth, slew rate and amplitude.. At any given amplitude the linear bandwidth will be limited by the slew rate. And at any given bandwidth the linear amplitude will be limited by the slew rate A simple voltage amplifier view on the relationship: http://www.falco-systems.com/high_voltage_amplifiers.html
CraigC Posted August 18, 2013 Posted August 18, 2013 (edited) Check the formulae for these definitions, then you'll see the interrelationships. Edited August 18, 2013 by CraigC
Addicted to music Posted August 18, 2013 Posted August 18, 2013 Keitha, Slew rate is the speed of change in voltage levels, and is messured in time typically in volts per microsec (V/us) It is the time it takes from say at zero volts to X amount of volts in 1.0 micro second, (low to high) or a fall from a X volts in 1.0 microsec (high to low). Generally speaking the higher this figure the faster it is. eg 100/us is faster than 10/us Bandwidth is the range in frequency, typically audio is 20hz to 20khz. Amplifiers can go into the Ghz range(microwave) Signal to noise ratio is the figure determined to show how accurate it produce the orignal signal , its normally measured by feeding a single test tone(say 1khz) into a device and the output is feed to an spectrum analyser to display the tone. If a product is accurate it will only produced this tone, however nothing is perfect, and what is display are other tones, The higher this figure that is measured in db, the more accurate it is. These are the three things you need to know to decipher what he is rambling on about and Im not going there. The higher the slew rate the better the amplifer, however other things come into play, things such as instability that leads to ocsillation, therefore in general, amps that are used for audio are limited or compensated for stability, With passive components such as signal passing capacitors that have the highest slew rate, often sound the best, but is it also due to the materials used that have less absorbtion rate and dissapation factor that contributes? Bandwidth in amplifiers are also limited to keep things in check as nothing man produced are in its pure form, and therefore, can degrade the signal if it isnt. Welcome to the world of electronic!
bzr Posted August 18, 2013 Posted August 18, 2013 (edited) Source? Read the second line in your signature. http://bit.ly/1cYgyAy Edited August 18, 2013 by groot
davewantsmoore Posted August 19, 2013 Posted August 19, 2013 Perception has been proved otherwise. Read the second line in your signature Unless you are troll, I am confuse.
davewantsmoore Posted August 19, 2013 Posted August 19, 2013 (edited) I don't really follow the logic of what he's trying to say (I have no idea what slew rates are), but the article looks very much like an opinion piece. It is an "opinion" based on extremely basic (ie. well known) facts of audio. What he is saying about the SNR of 16 vs 24 bit... is by any measure "not controversial" (understatement). He seems to be claiming that the only difference between 16 bits and 24 bits is the signal to noise ratio. but is this really true? Yes. That's correct. The (only) difference is the SNR. It is possible that 24bit audio can sound better due to the operation and design of some DA converters (not that 24bit is "better" .... but that some converters work better with 24bit) .... but this is not a property of audio, more than it is a reflection on DA converters. He doesn't provide any references to back up his claims. He doesn't (really) need to, as what he is saying is "fundamental". Jump on wikipedia for "bit depth". Edited August 19, 2013 by davewantsmoore 1
davewantsmoore Posted August 19, 2013 Posted August 19, 2013 The bit depth and SNR allow some flexibility in the signal chain. 24bit can certainly get much better than the 120dB ceiling he suggests and he's correct the SNR of subsequent stages will normally be the limit on the SNR at output of the power amplifier. He seemed to be saying that 120dB was the "new standard" of achievement (not that it was the limit of 24bit). ... which i think is about fair enough.
Willco Posted August 19, 2013 Posted August 19, 2013 If I 've read right Matti Otala wrote a paper on slew rate in Audio. I've owned his original Ampliwire Amp-a little 60Watt Jewel from Norway. Willco
davewantsmoore Posted August 19, 2013 Posted August 19, 2013 Just another audio writer with an opinion. How very rare. Just another forum jockey disparaging anyone with an opinion without providing any analysis of said opinion..... ?!
bzr Posted August 19, 2013 Posted August 19, 2013 (edited) Unless you are troll, I am confuse. ---------------------------. never mind. Edited August 19, 2013 by groot 1
Phantom Posted August 19, 2013 Posted August 19, 2013 Just another forum jockey disparaging anyone with an opinion without providing any analysis of said opinion..... ?! ...and you, I guess are not "just another forum jockey?" Whatever
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