The iPad Pro (as well as some other, lower cost new iPads), has a USB-C connection these days. The largest capacity iPad currently available has 1 TB of storage on board, room enough for at least 1500 CDs. Such an iPad costs about $1,500. Some iPad Pro users have suggested using a general purpose iPad Pro as their streamer, saying there is no need to buy any dedicated music server--just hook your iPad Pro up to a USB-C connection whenever you want to listen to music through your system.
Such an iPad should be able to pass whatever digital audio signal you can access from a streaming service or have saved to disc on the iPad to your DAC, for example a Benchmark DAC3. According to tests, Apple has not dumbed down the iPad's USB-C output and it can thus pass bit--perfect data even from high resolution digital files. If you have, for example, a Benchmark DAC, the Benchmark's front panel display should tell you the resolution of the signal it is receiving from any program. If the lights indicate it is receiving the full resolution of the source you are sending, the iPad Pro should work at least reasonably well as a music streaming device.
Apple's AirPlay is limited to 16/44, for example, so any attempt to output higher resolution gets downsampled to that resolution. I know the old Apple Airport Express digital output (the combination stereo miniplug/optical digital jack) was also limited to 16/44 resolution. That was actually better sounding than the Apple TV units which altered everything to 16/48.
Certainly there is nothing "wrong" with using an iPad Pro as your music source. You could, of course, try A/Bing it against a "real" music player/streamer. Perhaps you could borrow a good dedicated streamer from a dealer or friend for a couple of days and try experimenting with both high and low resolution content. If you can't hear any difference, or if any difference you hear is either sonically insignificant or not clearly better or worse, just different, then the iPad Pro may well be a fine solution.
I use a late model iPad Pro in my system as a controller for my Lumin X1. I can also play tunes from it via AirPlay to the Lumin. I do not have it wired to the system with USB or other cabling.
One reason for going beyond the iPad Pro as a music streamer is if you want to use Roon. Roon requires a "real" computer as the Roon Core from which the music is sourced. An iPad Pro cannot be used as a Roon Core. In my system my iPad Pro controls a Roon Nucleus+ which does the streaming either from online services or a 1 TB USB stick plugged into the back of the Nucleus+. The Nucleus+ is a stripped down high performance computer dedicated solely to music serving.
A USB-connected iPad as the music source is one thing I have not tried. I've simplified my system to such an extent that I no longer have a USB digital signal pathway to my amps. My current Dutch & Dutch 8c speakers don't allow me to drive the amps in the speakers from a USB connection. I'd need some sort of USB to SPDIF conversion.
Roon aside, I certainly agree that if I could have only one streaming service, Qobuz would be it. Spotify has the most albums of any streaming service but as yet is not even CD quality. Qobuz is deeper in the classical and jazz catalogs than Tidal, whereas Tidal is much deeper into genres in which I have little interest. The Qobuz Hi Res albums usually are at least as good sounding as Tidal's MQA version (although they frequently sound quite different) and eliminate the need for software or hardware which will decode/unfold MQA. The Benchmark DACs, for all their merit, do not do MQA, so Qobuz is clearly your best choice for a high resolution streaming service if you don't have a means for decoding MQA files.
The Benchmark DAC3 units are indeed superb for PCM digital playback up to 24/192. I use a Benchmark DAC3B for my electrostatic headphone system to drive Stax SR009S headphones via a Mjolnir amp and this is the best sounding headphone set-up I've ever owned.
As to the comparative quality of metadata of Qobuz vs. Roon, I'm not sure why some might find Qobuz to be superior. Do they like the album reviews better on Qobuz? Qobuz does seem to link to all the albums on a particular label, which Roon does not do well. Or maybe they like the way Qobuz categorizes music into subgenres better than Roon does. But those are not the metadata most people are interested in. For example, look at the credits for any randomly selected album and how many of the people or groups named are links to their other work--very few on Qobuz, most on Roon. Also, Roon integrates your own music files into a unified library with your Qobuz and Tidal favorites which Qobuz on its own cannot do, of course.
I think many people prefer to have the overlay of the streaming software used by dedicated streamers to that of the native Qobuz software. For example, many folks really like the way the Lumin app organizes things; the same goes for BlueSound and especially for Roon. This software overlay is something you don't get with just native playback of Qobuz on an iPad.
And some streamers, like the Lumin U1 Mini I previously owned and the X1 I now own, allow upsampling/resampling, decode MQA, and handle native DSD files with aplomb. The iPad doesn't do those things, at least not without addition of apps. But, I agree that, at the end of the day, none of those are really needed once you have a streaming service of Qobuz quality. I think most music sounds most natural when not upsampled/resampled, MQA is only different not really better than Qobuz's high res files, DSD resampling is, again, at best just different sounding, not better, and the number of native DSD recordings is miniscule.
Years ago I used an Apple Airport Express (about $150 at its peak price, as I recall) as my main streaming device. I've used various iPhones and iPads as streamers as well, just never via a USB output. I've also used dirt cheap streamers such as Chromecast Audio. They all work and sound quite good. I've also now owned and used a number of other more expensive streamers from Logitech (Squeezebox Touch), BlueSound, Auralic, and now Lumin. They may all be bit-perfect, but if we thought that was all that mattered sonically, then the very first Sony CD player would truly have provided Perfect Sound Forever.
I'm not saying my Lumin X1 streamer is worth its $15k price compared to a "free" streamer like the iPad Pro's USB-C output. But then you don't really know how good your iPad sounds as a streamer unless you compare it in your system to a dedicated music streamer with a good reputation.
Why anyone would buy a $15k music streamer is a very good question since no one would argue that $15k will make anywhere nearly as large a difference in your sonic reproduction quality as $15k invested in good speakers (e.g., the cost of the Larsen 9s) versus el cheapo $39.95 speakers. An iPad Pro used as a streamer and also for other personal use is basically "free" and surely works quite well enough sonically to make a fine sounding audio front-end even with $15k speakers like the Larsons.
I think most here would agree that speakers, rooms, system set-up (primarily the positioning of speakers and listener) and room treatments are the most important elements of home audio in terms of sonic results. Room treatments can cost a bit, but most are not super expensive. The room, unless you are building one from scratch to create a reflection-free zone like the one REG talks about, is just a matter of what you have available to work with, given your circumstances and judgement. Set up is also either free or inexpensive, just time consuming to get right. Speakers are thus the big-bang-for-the-buck element. Even I agree with that.
All the electronics, cabling, powerline quality, etc. are less sonically important to the final result. While changes may well be audible, they are not as obvious and thus probably not as important to your enjoyment.
It is indeed one of the wonders of our current age that a streaming audio front end can be basically free these days (except for the cost of the streaming service) and sound quite fine even when paired with the finest speakers. Surely any sonic differences among streaming front ends do not remotely approach the sonic differences between a child's $39.95 phonograph and a high-end turntable/tonearm/cartridge properly mounted for vibrational isolation, something which can easily cost many tens of thousands of dollars these days. Most of the mechanical factors are eliminated with streaming, program material is about as broad, and convenience is overwhelmingly superior.
Such an iPad should be able to pass whatever digital audio signal you can access from a streaming service or have saved to disc on the iPad to your DAC, for example a Benchmark DAC3. According to tests, Apple has not dumbed down the iPad's USB-C output and it can thus pass bit--perfect data even from high resolution digital files. If you have, for example, a Benchmark DAC, the Benchmark's front panel display should tell you the resolution of the signal it is receiving from any program. If the lights indicate it is receiving the full resolution of the source you are sending, the iPad Pro should work at least reasonably well as a music streaming device.
Apple's AirPlay is limited to 16/44, for example, so any attempt to output higher resolution gets downsampled to that resolution. I know the old Apple Airport Express digital output (the combination stereo miniplug/optical digital jack) was also limited to 16/44 resolution. That was actually better sounding than the Apple TV units which altered everything to 16/48.
Certainly there is nothing "wrong" with using an iPad Pro as your music source. You could, of course, try A/Bing it against a "real" music player/streamer. Perhaps you could borrow a good dedicated streamer from a dealer or friend for a couple of days and try experimenting with both high and low resolution content. If you can't hear any difference, or if any difference you hear is either sonically insignificant or not clearly better or worse, just different, then the iPad Pro may well be a fine solution.
I use a late model iPad Pro in my system as a controller for my Lumin X1. I can also play tunes from it via AirPlay to the Lumin. I do not have it wired to the system with USB or other cabling.
One reason for going beyond the iPad Pro as a music streamer is if you want to use Roon. Roon requires a "real" computer as the Roon Core from which the music is sourced. An iPad Pro cannot be used as a Roon Core. In my system my iPad Pro controls a Roon Nucleus+ which does the streaming either from online services or a 1 TB USB stick plugged into the back of the Nucleus+. The Nucleus+ is a stripped down high performance computer dedicated solely to music serving.
A USB-connected iPad as the music source is one thing I have not tried. I've simplified my system to such an extent that I no longer have a USB digital signal pathway to my amps. My current Dutch & Dutch 8c speakers don't allow me to drive the amps in the speakers from a USB connection. I'd need some sort of USB to SPDIF conversion.
Roon aside, I certainly agree that if I could have only one streaming service, Qobuz would be it. Spotify has the most albums of any streaming service but as yet is not even CD quality. Qobuz is deeper in the classical and jazz catalogs than Tidal, whereas Tidal is much deeper into genres in which I have little interest. The Qobuz Hi Res albums usually are at least as good sounding as Tidal's MQA version (although they frequently sound quite different) and eliminate the need for software or hardware which will decode/unfold MQA. The Benchmark DACs, for all their merit, do not do MQA, so Qobuz is clearly your best choice for a high resolution streaming service if you don't have a means for decoding MQA files.
The Benchmark DAC3 units are indeed superb for PCM digital playback up to 24/192. I use a Benchmark DAC3B for my electrostatic headphone system to drive Stax SR009S headphones via a Mjolnir amp and this is the best sounding headphone set-up I've ever owned.
As to the comparative quality of metadata of Qobuz vs. Roon, I'm not sure why some might find Qobuz to be superior. Do they like the album reviews better on Qobuz? Qobuz does seem to link to all the albums on a particular label, which Roon does not do well. Or maybe they like the way Qobuz categorizes music into subgenres better than Roon does. But those are not the metadata most people are interested in. For example, look at the credits for any randomly selected album and how many of the people or groups named are links to their other work--very few on Qobuz, most on Roon. Also, Roon integrates your own music files into a unified library with your Qobuz and Tidal favorites which Qobuz on its own cannot do, of course.
I think many people prefer to have the overlay of the streaming software used by dedicated streamers to that of the native Qobuz software. For example, many folks really like the way the Lumin app organizes things; the same goes for BlueSound and especially for Roon. This software overlay is something you don't get with just native playback of Qobuz on an iPad.
And some streamers, like the Lumin U1 Mini I previously owned and the X1 I now own, allow upsampling/resampling, decode MQA, and handle native DSD files with aplomb. The iPad doesn't do those things, at least not without addition of apps. But, I agree that, at the end of the day, none of those are really needed once you have a streaming service of Qobuz quality. I think most music sounds most natural when not upsampled/resampled, MQA is only different not really better than Qobuz's high res files, DSD resampling is, again, at best just different sounding, not better, and the number of native DSD recordings is miniscule.
Years ago I used an Apple Airport Express (about $150 at its peak price, as I recall) as my main streaming device. I've used various iPhones and iPads as streamers as well, just never via a USB output. I've also used dirt cheap streamers such as Chromecast Audio. They all work and sound quite good. I've also now owned and used a number of other more expensive streamers from Logitech (Squeezebox Touch), BlueSound, Auralic, and now Lumin. They may all be bit-perfect, but if we thought that was all that mattered sonically, then the very first Sony CD player would truly have provided Perfect Sound Forever.
I'm not saying my Lumin X1 streamer is worth its $15k price compared to a "free" streamer like the iPad Pro's USB-C output. But then you don't really know how good your iPad sounds as a streamer unless you compare it in your system to a dedicated music streamer with a good reputation.
Why anyone would buy a $15k music streamer is a very good question since no one would argue that $15k will make anywhere nearly as large a difference in your sonic reproduction quality as $15k invested in good speakers (e.g., the cost of the Larsen 9s) versus el cheapo $39.95 speakers. An iPad Pro used as a streamer and also for other personal use is basically "free" and surely works quite well enough sonically to make a fine sounding audio front-end even with $15k speakers like the Larsons.
I think most here would agree that speakers, rooms, system set-up (primarily the positioning of speakers and listener) and room treatments are the most important elements of home audio in terms of sonic results. Room treatments can cost a bit, but most are not super expensive. The room, unless you are building one from scratch to create a reflection-free zone like the one REG talks about, is just a matter of what you have available to work with, given your circumstances and judgement. Set up is also either free or inexpensive, just time consuming to get right. Speakers are thus the big-bang-for-the-buck element. Even I agree with that.
All the electronics, cabling, powerline quality, etc. are less sonically important to the final result. While changes may well be audible, they are not as obvious and thus probably not as important to your enjoyment.
It is indeed one of the wonders of our current age that a streaming audio front end can be basically free these days (except for the cost of the streaming service) and sound quite fine even when paired with the finest speakers. Surely any sonic differences among streaming front ends do not remotely approach the sonic differences between a child's $39.95 phonograph and a high-end turntable/tonearm/cartridge properly mounted for vibrational isolation, something which can easily cost many tens of thousands of dollars these days. Most of the mechanical factors are eliminated with streaming, program material is about as broad, and convenience is overwhelmingly superior.