rjp Posted June 3, 2018 Share Posted June 3, 2018 I have been using a subscriber Spotify account at highest quality and no normalization as my sole audio input source to my VTA70 tube amp and Klipsch RP-260F system. Is this good enough? I have read a little discussion of others saying so other digital formats are much better and I would like to learn more. As an EE I do understand the mathematics of sampling rate and the effect of bit length of samples (resolution) on SNR. I am also fairly familiar with compression algorithms, at least in concept. I guess the first question is, what exactly am I getting from Spotify streaming? Clearly it must be a compressed format, and I would assume it is a lossy compressed format., Correct? Is it MP3? What is it's average bitrate at highest quality level? Is this good enough for HiFi 2.0 listening? Is there a streaming source for lossless formats for comparison? Also, what about the quality of the D/A in the iPhone. Is this good enough? I have read testing results claiming that(beginning with the 5s) the specs as far as IMD, SNR, and freq response are as good as any stand alone unit I could buy. I think this DAC is limited to 16 bit formats. I assume it is more important to have a perceptualy lossless compression algorithm, high sampling rates, and good filters than to increase the sample resolution from 16 to 24 bits. Quote Link to comment Share on other sites More sharing options...
pbphoto Posted June 3, 2018 Share Posted June 3, 2018 I don't use Spotify but a quick web search shows that it uses the Ogg Vorbis (open source MP3) compressed/lossy format to stream to your iPhone. Within the iPhone app, you can choose the stream quality level you want all the way up to ~320kbs (extreme setting.) From there, the DAC inside your iPhone converts it to analog and sends it over to your VTA 70. In an ideal world, a lossless CD quality stream would be preferred but I think the higher-quality/higher-bitrate lossy encoders do a fantastic job - real tough for me to tell a difference. For a low cost upgrade, there are several external DACs that are compatible with iPhones (some need a cable, some are a cable with a DAC built-in) that you can try. On my MacBook, I use a Dragonfly DAC that's several years old for headphone listening and it made a noticeable improvement over the onboard DAC. Some of this is due to it's ability to drive the headphones, but some of it is because it has a better DAC. Quote Link to comment Share on other sites More sharing options...
rjp Posted June 3, 2018 Author Share Posted June 3, 2018 Thanks Quote Link to comment Share on other sites More sharing options...
avguytx Posted June 4, 2018 Share Posted June 4, 2018 I don't use my phone as a source (Galaxy S7) but using it in my truck tied into a Pioneer head unit that has Android Auto sounds fine. At home, I have a SFF desktop PC that uses the Spotify desktop app with USB out to my Onkyo P-3000R preamp via USB connection and it sounds pretty good overall. Even at high quality setting, it's only 320k max. Tidal, Deezer and maybe a couple others, are the only that offer lossless streaming on a lot of music. But still sounds pretty good overall for the flexibility of having a lot of music at your fingertips....at a slight loss of SQ. Quote Link to comment Share on other sites More sharing options...
rjp Posted June 4, 2018 Author Share Posted June 4, 2018 Thanks for the info. So Spotify on highest quality is about 320kbps, which if I calculate correctly is about 1/4 of the bit rate of CD audio. I wouldn't expect much SQ loss at this level of compression. My guess is that it would not be audible to most listeners. Am I wrong? Can people reliably identify CD (or lossless compression) vs 320k MP3 in blind testing? Quote Link to comment Share on other sites More sharing options...
pbphoto Posted June 4, 2018 Share Posted June 4, 2018 3 minutes ago, rjp said: Thanks for the info. So Spotify on highest quality is about 320kbps, which if I calculate correctly is about 1/4 of the bit rate of CD audio. I wouldn't expect much SQ loss at this level of compression. My guess is that it would not be audible to most listeners. Am I wrong? Can people reliably identify CD (or lossless compression) vs 320k MP3 in blind testing? I agree with all of the above - 320k MP3 sounds excellent. It's very very difficult for me to tell a difference - and that's only after concentrating and replaying a bunch of times (maybe). There are several online blind tests you can try for yourself. The source/mastering makes much more of a difference than 320k MP3 vs CD-lossless. Quote Link to comment Share on other sites More sharing options...
rjp Posted June 4, 2018 Author Share Posted June 4, 2018 This is great news. So feeding my Klipsch RP-260Fs with highest bitrate Spotify will not be limiting them in any way it seems. What about the built in DAC in the iPhone 5S. Is it really as good as I've read? Based on these measurements I can't see any reason why I would want to buy another DAC. What do you think? https://kenrockwell.com/apple/iphone-5s-audio-quality.htm Quote Link to comment Share on other sites More sharing options...
twk123 Posted June 4, 2018 Share Posted June 4, 2018 47 minutes ago, rjp said: This is great news. So feeding my Klipsch RP-260Fs with highest bitrate Spotify will not be limiting them in any way it seems. What about the built in DAC in the iPhone 5S. Is it really as good as I've read? Based on these measurements I can't see any reason why I would want to buy another DAC. What do you think? https://kenrockwell.com/apple/iphone-5s-audio-quality.htm I would be a little wary of Ken Rockwell's take as he is known for more amateur type reviews on the photography side and saying sensationalist things like not shooting RAW or why you dont need a tripod. Although he flipped later on the RAW shooting aspect and wears T-shirts advertising this fact. Personally, I would grab a Audioquest dragonfly for $100 on Amazon to listen side by side to the I-phone to see what is best, you can always return the dragonfly if it does not stack up. https://www.amazon.com/AudioQuest-DragonFly-Black-Headphone-Amplifier/dp/B01DP5JHHI/ref=sr_1_1_sspa?ie=UTF8&qid=1528126933&sr=8-1-spons&keywords=audioquest+dragonfly&psc=1&smid=AKR88PAWTQVN2 1 Quote Link to comment Share on other sites More sharing options...
pbphoto Posted June 4, 2018 Share Posted June 4, 2018 1 hour ago, rjp said: This is great news. So feeding my Klipsch RP-260Fs with highest bitrate Spotify will not be limiting them in any way it seems. What about the built in DAC in the iPhone 5S. Is it really as good as I've read? Based on these measurements I can't see any reason why I would want to buy another DAC. What do you think? https://kenrockwell.com/apple/iphone-5s-audio-quality.htm Agree with above - try a low-cost iphone-compatable DAC and see if you can tell the difference. To put it another way, there is no point in worrying about AAC 256 vs 320 MP3 vs CD-lossless and running it through the DAC in the iPhone. Quote Link to comment Share on other sites More sharing options...
rjp Posted June 4, 2018 Author Share Posted June 4, 2018 4 hours ago, twk123 said: I would be a little wary of Ken Rockwell's take as he is known for more amateur type reviews on the photography side and saying sensationalist things like not shooting RAW or why you dont need a tripod. Although he flipped later on the RAW shooting aspect and wears T-shirts advertising this fact. Personally, I would grab a Audioquest dragonfly for $100 on Amazon to listen side by side to the I-phone to see what is best, you can always return the dragonfly if it does not stack up. https://www.amazon.com/AudioQuest-DragonFly-Black-Headphone-Amplifier/dp/B01DP5JHHI/ref=sr_1_1_sspa?ie=UTF8&qid=1528126933&sr=8-1-spons&keywords=audioquest+dragonfly&psc=1&smid=AKR88PAWTQVN2 I am familiar with Ken Rockwell from my interest in photography. I know how unusual he is. That said, he did seem to use the right gear to perform these tests of the DACs, so even if he is a bit strange, I find it hard to dispute his measurements. LEt me give it another read and try to find some supporting data from others. Quote Link to comment Share on other sites More sharing options...
rjp Posted June 4, 2018 Author Share Posted June 4, 2018 3 hours ago, pbphoto said: Agree with above - try a low-cost iphone-compatable DAC and see if you can tell the difference. To put it another way, there is no point in worrying about AAC 256 vs 320 MP3 vs CD-lossless and running it through the DAC in the iPhone. I think you are assuming the DAC in the iPhone is not as good. There is no point is "upgrading" to an outboard DAC if the one in the iPhone is already better. Quote Link to comment Share on other sites More sharing options...
twk123 Posted June 4, 2018 Share Posted June 4, 2018 2 hours ago, rjp said: I am familiar with Ken Rockwell from my interest in photography. I know how unusual he is. That said, he did seem to use the right gear to perform these tests of the DACs, so even if he is a bit strange, I find it hard to dispute his measurements. LEt me give it another read and try to find some supporting data from others. I found the link and read the review and typical of Ken Rockwell, he mixes hyperbole with limited testing etc to throw out a conclusion. There are many aspects to a good DAC and how it creates a tone from a digital source beyond a flat response from the DAC/headphone amp. Personally, I would at least try one USB DAC so you have something to compare as a reference point. Here is a the link for others to chime in as well: https://kenrockwell.com/apple/iphone-5s-audio-quality.htm Quote Link to comment Share on other sites More sharing options...
rjp Posted June 4, 2018 Author Share Posted June 4, 2018 That is the same link I posted. Yes, it would be great to hear from others. In addition to frequency response KR also measured the harmonic distortion in that same article. THD seems really low. Assuming he knows how to use the R&S audio analyzer properly With freq response down only 0.1dB at 20KHz and a near immeasurably low THD its hard to point to any faults in the iPhone 5S DAC at least on paper. Still, for 100 bucks it might be worth at least listening to the Dragonfly. Certainly some of its reviewers feel it improved their iPhone performance. Maybe the difference is not something measurable? 0.00043% THD and harmonic distortion components at 1 kHz at -20 dBFS into 200KΩ at maximum volume setting. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.