Why some digital audio players just aren’t loud enough

This an edited and updated version of an article I originally published in the Apr/May 2019 edition of Sound+Image magazine. At the time of republication, the FiiO and Astell&Kern digital audio players I’ve tested do not implement these limits. I guess those which are sold into the European Union would be different, compliant, versions.

Thank you for nothing, EU.

I almost disappeared down a rabbit hole when trying to make sense of a frankly nutty design decision in the Pioneer XDP-30R portable music player. That led me, inevitably, to the European Union bureaucracy.

Let’s back up a step. I measured the maximum headphone output from this unit into an open circuit at 0.427 volts RMS (at 1kHz, I’ll use that for all my measurements in this article). That could well be too low an output to drive to satisfying levels some higher impedance, lower sensitivity headphones.

Now, Pioneer is a competent company, and in just about every respect its digital audio players are sweet devices. Its engineers know a hundred times more about headphones than I’ll ever know. It can measure electrical output more effectively than I can. It would be aware that there are such things as low sensitivity, high impedance headphones. So why would it set its player to such a low level?

It’s the rules

My theory: it’s due to rules that may, and probably do, require conformance of portable music players to European Standards EN 50332 and EN 60065. The first standard sets out a method of measuring output while the second concerns permissible maximums.

These rules seem to have come into effect in 2013. It seems likely that they were originally voluntary. But a World Health Organisation/ITU report, compiled at some point after October 2015, says that they are compulsory throughout the European Union and Switzerland (5.1.1 on page 18 of the PDF download here.)

They seem certain to be compulsory in at least some EU nations, which have independently implemented them in domestic law.

What do these demand? I’m not prepared to fork out the money to purchase the standards documents – $US139.70 for the British version of just one of them, funny how expensive it is to read the rules that govern our lives  – but I’ve been able to glean the following from various reports.

Part One of the two standards concern players with included earphones. They are supposed to default to a maximum output of 85 decibels. But European bureaucratic overlords will allow an override to 100 decibels, so long as the user has taken action to override the limit. In that case, they must be warned again at regular intervals. The test signal is shaped noise, so I guess those limits are the average of that noise.

These levels appear to have been settled upon to limit hearing damage to youngsters who may spend hour upon hour with headphones attached. I’m sure most readers would agree that 85 decibels is a remarkably unsatisfying level much of the time for your more refined bouts of listening. And, indeed, even 100 decibels would be inadequate from time to time.

That inevitably means reduced gain

Importantly: what about music encoded at a low level? Limiting gain to avoid excessive levels with highly modulated music necessarily means insufficient gain for music recorded at low modulation. And, yes, it does exist. Not everything has suffered from the jukebox effect. And a lot of that low-modulation music is classical.

Apple Lightning headphone adaptor
Apple Lightning headphone adaptor - a way of getting around Euro-rules?

Now, what about players which don’t include earphones? Levels depend on output level of the player and the sensitivity of the earphones or headphones. The relevant rules are in Part 2 of the standard.

And guess what these say? First, they require the player to provide a warning once the output voltage hits 27mV into a 32-ohm load. That’s about 30dB below the one-ish volts I like to see from a portable high resolution audio player or headphone amp/DAC. That Pioneer player issues such a warning once you wind it to 45 on the scale of 0-60. At that level, its output with my test signal was 59mV RMS into a 16-ohm load. I’m using a sine wave rather than the proper test signal, so I guess that’s comparable.

(I would replicate the test signal noise, but I haven’t been able to discover its average level).

The rules allow the volume to be advanced beyond that point, again with a warning that has to be repeated at regular intervals. And even then, there’s a hard output limit at 150mV. As I noted, the Pioneer player also tops out at under 430 millivolts RMS with test sine waves. That drops to 330 millivolts into a 16-ohm load. My guess is that it would top out at 150 millivolts on average using the official test into a 32-ohm load.

(Check of theory: my first measurement/stated standard = 59/27 = 2.19; my second measurement/stated standard = 330/150 = 2.20. Close enough I reckon.)

So, I reckon that the Pioneer XDP-30R high resolution audio player has been hobbled to comply with silly Euro nanny-state regulations, written with no consideration for listeners of refinement and care.

How hobbled?

If you’re not a numbers person, you may not have an intuitive feel for values like 27mV and 150mV. So let’s compare. A few months ago I measured the output of the Astell&Kern A&futura SE200 DAP. It produced well over 700mV into 16 ohms (just short of clipping) and more than two volts into 300 ohms, so it would likely manage a full volt into 32 ohms. That’s 16 decibels more than the Euro-hobbled player.

Astell&Kern A&futura SE200 DAP
Astell&Kern A&futura SE200 -- definitely not limited by Euro-rules here in Australia

It probably wouldn’t matter if you had super sensitive earphones, like the Campfire Solaris 2020 in-ear monitors, but with many regular headphones, achieving a satisfying level could be difficult.

Rule workarounds

It turns out these rules don’t apply to everything. They apply to things like portable FM radios, portable digital music players, portable CD players. I gather Part 1, the bit about 85dB, applies to phones* since they typically come with their own earbuds, although presumably not for those lacking a headphone output.

So how can you get around these rules? Well, in your home you’ll have no problems. There appear to be no legal issues for Europeans who wish to purchase a high-fidelity stereo amplifier with a headphone output capable of melting down both their ears and headphones. (At least, not in prospect. In retrospect one could always try suing.) For example, I have measured the output of the British-designed iFi Zen Can desktop headphone amplifier at more than 4 volts into 16 ohms. That’s more then 28dB above the Euro limit.

An iPod Touch would be limited to the 85dB/100dB regime (since it comes with its own buds), but an iPad Mini, which is essentially the same thing, but with a larger screen, wouldn’t be because it’s not primarily a music player.

And as far as I’ve been able to work out, a portable headphone amplifier/DAC is not subject to the rules because it isn’t a player. If your phone or portable audio player has a digital output, you can plug it into this output device and enjoy higher levels. Of course, that means another gadget in your pocket, so that’s rather unsatisfying.

An additional option for Europeans – one I’d recommend – is buying one of several fine Chinese- or Korean-origin portable digital music players online from overseas.

Another way, which would be pretty naughty, would be for a maker to bundle its music player with a very special set of earbuds. Because it has earbuds, the rules about volume level would apply, not output voltage. Those special earbuds could incorporate a carefully chosen in-line resister so that the player would have to run at a couple of volts to get the sound level up to 85dB. Purchasers would be expected to accept the implicit wink and nudge, toss the earphones and buy some decent headphones or earphones which, without the inline resistor, could be driven much louder.

How Pioneer lets users get around it

Pioneer is a mature, well-behaved corporate entity. It will play by the rules of the jurisdictions in which it operates. Apparently, we in Australia scored a European version, or perhaps Pioneer simply sold the same player across all markets.

But the unbalanced headphone output of the Pioneer XDP-30R doubles as a line output with the flick of a (virtual) switch. Another setting places the line output under the control of the volume knob.

And hey, presto, the output became 874mV (at clipping) into a 16-ohm load instead of 330mV. That’s 8.4 decibels more. And into 300-ohm headphones it went up to 1.99 volts from 0.42 volts. That is, 13.4 milliwatts instead of 0.6 milliwatts.

We’re in Australia, not Europe!

In an effort to keep their inventories streamlined, manufacturers sometimes lump Australia in with Europe – same voltage and mains frequency, after all. But if we’re going to be lumped with somewhere else, on this matter I’d prefer that we were lumped in with the US. To quote from the WHO/ITU report:

“[I]n 2010, the U.S. Court of Appeals for the Ninth District affirmed a 2008 decision by a California district court to dismiss a long-running lawsuit that claimed Apple iPods endangered users’ hearing. The original 2006 lawsuit ... claimed that iPods were defective because they could play music at unsafe volumes above 115 decibels (dB).

“The district court disagreed, saying that any dangers of hearing loss from playing music too loud were ‘obvious’ and ‘unavoidable.’”

I’m not so sure about the “unavoidable” part, but by golly the dangers are obvious.

But the fact that such dangers are obvious doesn’t mean that similar rules won’t eventually be applied in Australia too.

Meanwhile, I’d encourage readers to consider carefully reviews – particularly measurements of output – when contemplating the purchase of a portable music player. You could well regret purchasing a player which is hobbled by such rules.

If you can’t find a reliable Australian review of a product, then you should go a fine retail outlet for the products under consideration. Take your headphones or earphones with you and listen to the devices on your short list, just to make sure they will deliver the volume level that you want.

NOTE: I am not a lawyer, nor well versed in European law. If you are thinking of doing anything legally iffy, please obtain competent legal advice.

* I didn’t think of this when I first wrote this piece, but could these European rules have contributed to the elimination of headphone sockets on many phones? Remember, the rules do not apply things like Apple’s Lightning to headphone adapter.

Daps (digital audio players)