Advice needed on encoding music for iPad

I will be starting a new job, and I got a gift of an iPad pro 256gb for a going away gift. I want to play music at my new (desk) job, and will use the iPad for playing it. I have a pair of B & W MM1's that I will be using. My music will be mostly HDTracks downloads, vinyl transfers and some CD transfers. Right now they are almost all 24 bit hi-rez.

My question is, the MM1's have a D/A converter built in but it only goes to 16/48. I was wondering about the preferred encoding method to use for iTunes. Should I go with Apple Lossless? Would I even notice the difference if I used the Apple lossy encoding at a high bit rate? I could fit much more music on it this way.

Looking for your thoughts.

Thank you!

 

How much music - how many tracks do you want to put on the ipad pro?

 

If you're going to be using iTunes as your software player, then Apple Lossless (ALAC) is likely your best bet. ALAC is usually a variable bitrate CODEC which mainly means that silences are fully compressed to reduce file size, but music is compressed only slightly. The DAC in your MM1s can handle any ALAC word length/bitrate thrown at them from iTunes.

An alternative is to ignore the DAC in the MM1s in favor of a little Audioquest Dragonfly Red portable DAC (the new one just released a short time ago). You'll need a short adapter cable for the iPad Pro, plus a stereo 1/8" (mini-jack) cable to connect the output of the Dragonfly to the 1/8" (analog) input on the MM1, and the the result will be better sound. Substitute the Meridian Explorer2 portable DAC for the Dragonfly for an even better experience (and there's already a firmware update for the Explorer2 to make it MQA compatible). Just some suggestions.

Congratulations on being gifted an iPad Pro!

 

I probably have about 60gb of video material I want to store on it - the rest would be music.

 

I have the MM1s and like them a lot, attached to my PC or occasionally Mac.

If you are using them from an iPad, though, you would be using the analogue in anyway, presumably, as the digital input on the MM1 is a USB in. This would necessitate use of the headphone socket or some form of external DAC as the Lightning connector does not carry analogue audio. It may be possible to run audio from an iPad digitally via the camera connection kit to the MM1s, but I haven't tried this personally and wouldn't be surprised if it didn't work given that the MM1s were designed primarily as computer speakers. The internal DAC of the MM1s only works at 44.1/48K @16Bit and any higher resolution source would be converted to either of those formats. Similarly, the internal DAC of an iPad is limited to 48K / 24 bit maximum. I also don't know whether the analogue input of the MM1 goes through an ADC and subsequent DSP, which if it were the case would also be limited to 48K/16 bit.

If you really wish to play higher resolution files from an iDevice at their native resolutions, then an external DAC and a music player app such as Onkyo HF Player is probably the best solution. Using HFPlayer and an Oppo HA2 DAC / headphone amp, I can play high resolution files at their native resolution. Even with decent headphones, though, I make no claim that I can tell the difference between the same music file at 16bit / 44.1 bit or even AAC at 256K (though my hearing certainly isn't great). I doubt if I would be able to discern a difference between such files on the MM1s. As good as they are, they are small desktop computer speakers, and as mentioned above, may only work at 48K/16 bit internally.

Have a listen yourself. I leave my iPad on Apple Music (so AAC 256K) but sync various FLAC files at their native resolutions via Onkyo HF Player. As long as you have your music in a lossless format on your computer you can experiment and make the choice between formats to use on the iPad at your leisure.

 

Sevoflurane makes a great point. Have you actually tried the iPad Pro with a USB adapter cable running directly from the Lightning port into the USB input of the MM1? If not, be prepared for the dreaded "The device has insufficient power" error message. The problem is solved by using one of the portable DACs I recommended above and there are other good portable DACs to choose from as well. As Sevoflurane posted, the Apple camera connection kit is the best Lightning-to-USB adapter cable to use.

 

Hmmm... I was hoping to avoid spending any money on this. This is good advice, though. Will the Apple camera connection kit (I think they are $29 - I can spend that much) take the place of an in-line D/A converter as far as getting a digital signal into the speakers (avoiding that insufficient power message). I assume the D/A converter in the speakers is decent...

I might just go ahead and encode anything at 16/48. Chances are the difference on those speakers (good as they are) won't be heard while I am working anyway. I have my own office, but I assume there will be people in and out all day...

 

The point is that the iPad likely won't work when connected directly to the MM1 USB port because of the iPad's power config. This is a known problem with Apple's phones and tablets - it's related to battery life and power consumption. The camera connection kit is just an adapter cable, not a DAC.

Try the iPad with speakers though. Maybe B&W has designed the USB input to accommodate iPads and iPhones.

 

If you keep your music in iTunes, just keep it in its native sample rate / bit depth using Apple Lossless. That then gives you the option of transferring it in lossless to your iPad, or letting iTunes convert it to 256K AAC when you sync the music. Then you can see what it sounds like and what you are happy with and go with that. If you have music in other formats (FLAC / DSD / high bit depths or sampling frequency) you can sync those to your iPad and play them using Onkyo HF Player. If I can find my camera connection kit I will see if it works using my iPad Air and MM1s, but I have no idea where I have put it.

 

I'll give it a try tonight. I picked up a camera connector today to see if I need it.

I am using a Logitech base that connects to the iPad through the smart connectors (it charges it this way as well), which should keep the battery fully charged all day and allowing the lightning port to be free for audio. Fingers crossed!

 

Bowers & Wilkins MM-1 Desktop Computer Speakers »

Well, this review from Innerfidelity from 2012 suggests that the CCK trick works on an iPad. It also confirms that analogue audio goes through an ADC and undergoes DSP, though it is unclear what sampling frequency / bit depth is used internally. It's possible that the 48k/16bit limit is imposed by the USB interface as the DAC is 96k/24bit capable.

Confusingly, a user over on Head Fi has produced a response from B&W Support stating that the line in bypasses the DAC. I find that an odd response in a speaker marketed for its DSP, but there it is!

Googling around suggests mixed results from people comparing the USB and line inputs, with some people claiming better results from the analogue input via an additional DAC.

Personally, I quite like the idea of using the MM1 with an iPad, as it would be quite a neat system. I'd be interested to hear how you get on.

 

I would just use the lossless format. I see so many folks that whine about only being able to hold 5000 instead of 50000 tracks (or whatever number) on their device. Frankly I've started loading a lot less stuff on my mobile devices. It makes it so much easier to navigate and, be honest, you know good and well that there is a ton of stuff in your collection you are not going to listen to on the go or at the office.

 

Makes perfect sense. The line-in is an analog input. No reason for it to feed the internal DAC. Analog signals are never routed through a DAC.

Yes! Seem like a really clean, good quality desktop system. The OP will probably just need a portable DAC, so the expense will be reasonable. The new Audioquest Dragonfly Red DAC is really quite good.

 

I get the bit about the line in being analogue. I guess I just assumed that the sound of the speaker was the consequence of DSP. In such situations it is normal for analogue audio to go via an ADC to facilitate DSP. There are numerous examples of this.

This thread has got me very intrigued about the MM1s; I think I will experiment with them a bit more. Still can't find my camera connection kit!

 

Hmmm . . . I think you're right after all. The MM1 contains a class D (digital) amp and a DSP. According to the product web page the "Digital Signal Processing (DSP) constantly adjusts sound balance to keep bass effects powerful and music sounding rich and detailed, no matter how loud you play it." That most likely means that the analog input has to be converted via ADC in order for the (apparently) all-digital system to work. That would mean that everything inside the MM1 exists in or must be converted into the digital domain until the amp outputs an analog signal to the drivers.

 

Having found my old Camera Connection Kit, I can confirm that the MM1 works happily with my iPhone 6 and iPad Air, using either the normal Music app or Onkyo HF Player. The remote works fully; volume and track change work as normal. Note that I have the old Lightning / USB 2 cable without a separate Lightning connector to facilitate simultaneous charging. I see that Apple now market a newer Lightning / USB 3 cable which has this feature.

 

Good for B&W for making the MM1 compatible. You're all set.