Is My HiFi System Portable or Transportable?

General Discvssions & Theory/Vnderstanding
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First off, big disclaimer, this is just for fun. The discussion below is 100% non-scientific, completely made up, and the result of drinking and bullshiting with other audio nerds. So use at your own risk, and hopefully have some fun :upside_down_face:

With that said… what is the definition of a portable HiFi system?

Is anything than can run on batteries portable? Is it defined by size (ie pocketable), features, connectivity? Some exceptionally creative listeners have found ways to use battery packs to power small desktop devices on-the-go. Does this make it “portable”? What if I put a diesel generator in a wagon and power a full tube DAC and amp from it? Is that “portable”?

We all have collections of cell phones, iPods, DAPs, IEMs (with and without wires), headphones (with and without wires), DACs (some that dangle and some that dongle), Amplifiers, and speakers. Not to mention battery packs, DC/AC power inverters, AC/DC power rectifiers, and god help you if you use a diesel generator.

To help clarify this deeply troubling and all-important question for our community, the concept of “transportable” has started being used. If a setup can be moved for away from home listening, then it’s “transportable”. But where is the line then between “portable” and “transportable”?

side note:
Regarding the line between “transportable” and “stationary”, I put this line at the need for AC power from a wall. This will always tether you to the longest extension cord you have. If you have an AC cord long enough, go for it. But you really are stationary if you have a leash tethering you.

I subjectively think of “portable” as something I can listen to while moving around: walking, running, moving about in some way. Everything is in a pocket or in an ear. “Transportable” is a step up from this where it is still battery powered but requires a place to set it down. It’s too complex to live in my pockets. This is clearly a personal thing - some of us have tighter pants than others - so the amount of pocket space varies. But appropriateness of apparel aside, this is how I subjectively view it.

Now, if I’ve learned anything from the internet, subjectivism isn’t acceptable. Everything MUST be objectively defined. Or else you get yelled at on forums. So to avoid the yelling, bringing world peace to us all, I would like to help define an objective measure to clarify what is portable and what is transportable.

The measurement I have defined for us is the “Mobility Factor” (or “MF”). It is a point system for your setup, that you add up to achieve a total score, or Mobility Factor. The unit of Mobility Factor is “complexity”. So for example, a system will have a Mobility Factor of 3 complexity. (Comparing to a similarly useful measurement, SINAD is measured in units of dB. Mobility factor is measured in units of complexity.) The point system is as follows:

  • 1 point for every battery
  • 1 point for every wired connection

I have arbitrarily conclusively decided:

  • MF <= 3 Complexity: portable
  • MF > 3 Complexity: transportable

Examples
With this cosmic constant now rigorously defined, let’s look at a few examples:

  • AM/FM wireless headphones: 1 battery, 0 wires → MF=1 → portable
  • Cell phone playing out speaker: 1 battery, 0 wires → MF=1 → portable
  • Cell phone with wired IEMs: 1 battery, 1 wire → MF=2 → portable
  • Cell phone with wireless IEMs: 2 battery, 0 wires → MF=2 → portable
    (I’ve semi-arbitrarily decided wireless IEMs count as 1 battery in the charging case, since that is the thing that is charged.)
  • Cell phone with wired dongle DAC and IEMs: 1 battery, 2 wires → MF=3 → portable

You get the idea…

Now looking at some interesting specific products, so I can look down my nose of superior scientific rigor and judge them as portable or transportable:

Chord Mojo:
Cell Phone + USB into Mojo + wired IEMs: 2 batteries, 2 wires → MF=4 → transportable (sorry Mojo, you are just too MF complex to use as portable, you are hereby judged transportable)

BUT

Mojo + Poly (with SD card storage) + wired IEMs: 2 battery, 1 wire → MF=3 → portable (redemption!)

Cell phone + Mojo + Poly + wired IEMs: 3 battery, 1 wire → MF=4 → transportable (sorry, just too many batteries to keep charged and things to carry around for this to be properly portable)

So, if Mojo wants to use the term portable, it must be in conjunction with the Poly and an SD Card. Otherwise, it is henceforth transportable.

Chord Hugo:
Cell Phone + USB into Hugo + wired IEMs: 2 batteries, 2 wires → MF=4 → transportable (no surprise)

BUT

Cell Phone + Bluetooth into Hugo + wired IEMs: 2 batteries, 1 wire → MF=3 → portable (Hugo can be standalone portable, but Mojo cannot)

Hugo + 2Go (w/ SD Card) + wired IEMs: 2 batteries, 1 wire → MF=3 → portable (just kinda big)

Hugo is actually MORE portable than Mojo because it supports bluetooth without an extra adapter!

A more extreme example, Schiit Fulla
Schiit Fulla + 5V Battery Pack + USB Power Cable + Cell Phone + USB Data Cable + IEMs: 2 battery, 3 cables → MF=5 (transportable)

I think this makes sense. It can be run this way while sitting on a long flight or some place away from AC power. Making it a “useful” transportable setup. But it is more MF complex than using a Mojo or Hugo.

So if you want to go audiophile wild, fine. you are hereby dubbed “transportable” with your battery pack. But try to keep the MF complexity < 6, for your own good!

Conclusions
If you have read this far, well done!

And if you have correctly ascertained that I created this whole thing to make a point about the Chord Mojo not being portable, good for you! That’s correct! I’ve always thought the Chord Mojo was too unwieldy to be truly portable. It’s a nice device, but it’s good for transportable setups (listening on long flights, in the office, etc). Not for walking around. I would rather use a Hugo2 for walking around, via Bluetooth.

Personal crusades aside, I do think the Mobility Factor is interesting. It does draw lines in places that match my experience: dongle DACs are reasonably portable and usable. If there are too many battery powered things involved, it becomes a pain to keep them all charged. You can get a battery pack for your Schiit Fulla (or other low power desktop device) and be transportable.

Hope you enjoyed this!

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Imo your battery language needs some work. I think you should count “battery packs” (ies 4x AA still counts as one battery) and anything rigidly connected together as a single device (poly + MOJO, sp1k + amp, etc). Lastly, I think you need to add a size modifier. I recommend we call this PCB (pocket = 1, cargo shorts = 2, backpack = 4) and apply it as “each one required over a single normal sized pocket adds the points listed above”.

I think this also preserves the point that the MOJO isn’t portable (I agree, though I also don’t like dongles like at all) while improving the portability score of the poly+MOJO since I genuinely do think that works quite well.

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i could be convinced of this. I think when connected they charge together, and act as one battery. If we stick with my assessment of true wireless IEMs as “1 battery”, then we can probably go with rigidily connected batteries count as “1 battery”.

i like this. it’s like a side measure to MF Complexity. Maybe it’s PCB Appropriateness. The less appropriate you dress, the fewer PCB points you can support. Bikini = 0 appropriateness (not trying to make a social point, I like bikini’s as much as the next guy, just funny to measure this way), so therefore can support only PCB=0 (which maybe true wireless IEM’s would fit?). but if you have pants that aren’t too tight, you can support PCB=1 appropriatness, and support devices at that level…

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my DAC, two amps and streamer are all connected to the same AC regenerator, does that make it count as one then? with the right power cables it can be rigid enough.

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sure, but it still needs plugged into the wall, which puts it as “stationary”. if you have a battery pack to go with it, and a DC/AC inverter, then yeah, you could be transportable. but my guess is the MF Complexity is through the roof! :smiley:

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I was actualy thinking today that if I wanted, I could go one day to uni while using my Bakoon HPA-21 as an amp with my IEMs, since it’s battery powered.

And now I had this idea…
Phone + USB data cable into dac + (5V battery powered PSU + power cables + Soekris dam1941) + RCA into amp + Bakoon HPA-21 + IEMs/Headphones: 3 batteries, 4 cables → MF=7.

Oops.

This is such a stupid idea, but honestly, it might be a cool project, something to do just for fun and as a proof-of-concept. Now I’m intriguied aaaah!

I’m already imagining it: I’ll buy another backpack and stuff it inside with something rigid to keep everything in place. This is also so that I can space the amp and dac from the bottom of the backpack to give room to all the various cables.

There will be a compartment for the amp and one for the dac inside of it, while the dac’s battery pack will sit in the front pocket. Here there will also be a little pouch to put my IEMs.
As for space for my HD800S, I…guess I’ll hang them around my neck yeah, sounds cool.
I could use some big like, Pelican case and stuff them in there, but I would probably need a much bigger backpack, which could be still somewhat reasonableas long as I find one with jsut the right size to fit everything in there.

Now I’m talking as if it’s going to be the next thing I’ll do tomorrow, lol. If ever do it I guess it could be useful when I’ll eventually go to some headphones meetup like CanJam UK or some other audio event, or maybe even on train, although HD800S aren’t really the most portable/best outdoor headphones out there.

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:rofl: Nice one!

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all I ask is that you take pictures if you do!

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Oh yeah I’ll defintiely document my journey if I’ll do it. Okay, it’s more a when I’ll do it but still, I have a couple of projects that come first lol.

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Without size modifiers a dmp-z1 → ta1a → SR1a has a MF of 3 making it truly portable

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My primary hpa-21 use case was p6 → 21 → sus for couch listening

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Wow I guess I have pretty simple standards for what I think of as portable vs trans vs stationary

If AC power = stationary, otherwise if battery powered (or can be run on battery with external battery supply, ie something with reasonable voltage dc in)
If backpackable = trans
If pocketable (including cargo or jacket pocket) = port

Don’t really take into account number of cables/connections, but I do take into account number of overall boxes excluding transducers, if it’s over 3-4 that’s too much even for backpackable

I mean I’d say that even something like a p6p → mk424 is portable with some of the typical jackets or hoodies I wear, but something like a lpgt ti → hpa21 or broadway isn’t because you can’t fit those into a pocket

Technically you can use transportable on the go simply with just a backpack, just have electronics in bag, and then use a dap/transport that can be controlled via a phone, so the only cable you interact with is the one going from the backpack to the transducer.

Dumbest portable backpack setup I’ve done was a Nagra classic dac + mps (with the battery supply) + hpa21 + 800s

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The pure thought of this dac being used in a backpack while on the move makes me happy

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I would have done it with the HD dac when I upgraded, but given it has a tube in there I didn’t want to risk it, and was already being very very careful to not break it while it was still in the bag lol. Would never suggest it. Lasted longer than I would have expected though

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I think Nagra started out with field recording devices so I can see this. Either way it’s pretty badass.

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