Sennheiser HD25 Closed Back Headphones

SENNHEISER HD 25 LIGHT Closed-Back Headphones

The sound of a classic at an accessible pricepoint, Sennheiser’s HD 25 Light proves its worth as more than just a DJ headphone.

Review: Preshan John

TAKE YOUR PICK The Sennheiser HD 25s are available in three offerings. While the new HD 25 Light is cheapest, the established HD 25 model sports a single sided cable, split headband and rotatable ear cup. The HD 25 Plus is the deluxe package — same headphones but with an extra cable, extra ear pads and carry pouch thrown in.

Lightweight and unobtrusive, Sennheiser’s

HD 25 on-ear headphones may not impress with their looks but effortlessly impress with their sound. Those little earcups deliver big sound and a thumping bottom end without sucking anywhere nearly as much amp juice as your reference open-backs. In fact Sennheiser boasts of the HD25’s ability to handle sky high SPLs without exploding, making it an ideal tool for audio monitoring in various applications – from a recording engineer to a cameraman to a DJ.

Sennheiser has long considered the HD25 a ‘DJ headphone’ because, besides the punchy bass, it has a rotatable ear cup and both earcups slide straight off the headband to allow for walkie-talkie style one ear listening. Newly added to the family at NAMM 2020 is the HD25 Light – the cheapest route to HD25 sound but with a simplified headband that still lets the earcups slide off, but not rotate.

ON EARS I spent time listening to my favourite playlists through the HD25 Light and found them an easy listening headphone that left my desire for clarity satisfied. Sennheiser states it has the same driver as the original HD25 however a close look at the spec sheet reveals slight differences in impedance (60Ω rather than 70Ω), and frequency response (16Hz22kHz compared to 16Hz-22kHz) – perhaps due to a variation in circuitry. While I didn’t have a ‘normal’ HD25 to A/B with the Light, there’s a definite shyness in the high end that I’d otherwise have put down to the closed back design. Rather than being open and spacious, the soundstage feels more enveloping and intimate. At times the blossoming bass presence was a touch excessive, especially in the low mids, but if you’re a DJ this is the last thing you’d complain about.

Comfort is average over long listening periods with a slightly tight fit on my head. If you care about comfort you can swap out the stock synthetic leather earpads for Sennheiser’s softer velour option. The skinny plastic headband feels flimsy when bent so I’d be wary of tossing the HD25s in a bag of cables or hardware, where they could get damaged.

Excellent isolation from surrounding noise combined with minimal audio bleed make the HD25 Light great for the tracking room or a drummer on a live stage — or even as a casual listening headphone on public transport. It’s a no frills, no fuss pair of cans. They might be pitched as DJ headphones but don’t let that turn you off. The Sennheiser HD25 Light is equally indispensable to an audio engineer.

PRICE $179 RRP CONTACT Sennheiser: (02) 9910 6700 or sales@sennheiser.com.au PROS • Impressive tone with gutsy lows • Lightweight CONS • Headband feels a little delicate SUMMARY Sennheiser’s HD25 Light won’t disappoint as a trusty ‘desert island’ monitoring tool for audio engineers or recording musicians. Professional enough for critical listening yet portable enough for field recording or live performance, the HD 25 Light is an affordable all-rounder that sounds bigger than its size.

PC Audio

Sometimes PC plug-ins can have almost subliminal effects, but in combination these can become sublime.

Column: Martin Walker

Many PC effect plug-ins now arrive with serious audio performance that would have been unheard of a few years ago and, when modelled from hardware gear, can sound uncannily close to their original inspiration. Nevertheless, where hardware and software versions of the same item of gear are compared in detail by reviewers, the software version invariably gets close, but will never get the cigar. Now you may think there’s an element of politics involved in such statements, but I firmly believe that there are also more subtle forces at play. Despite both hardware and software plug-in alternatives seemingly offering identical specifications, in hardware the result is a cumulative one, resulting from the many smaller audio changes that happen at each electronic stage.

So, for example a typical low-end frequency response of perhaps -3dB at 10Hz in a hardware unit is achieved via a combination of various interstage coupling capacitors (each providing its own cutoff characteristic), along with the low-end rolloff of input and output transformers and the like. Each of these components and others will alter such things as frequency and phase response, harmonic distortion and so on in subtle ways, and during the hardware design phase, final component value tweaks across all the stages are only made after lots of detailed listening tests. On the other hand, while some plug-in designs (particularly the more expensive ones!) do claim to model the hardware on a component by component basis, many plug-in equivalents are likely to simply roll off the low end with a suitable algorithm – the result may still be a rolloff of -3dB at 10Hz, but a lot of the audio hardware subtlety may be lost in the process.

GO FORTH & MULTIPLY Hardware or software gear can also be cascaded in series, such that each device adds a little to the overall effect. I’ve heard this technique called ‘sonic varnishing’ — adding layer upon layer of more subtle effects to hopefully achieve audio nirvana. This can, for instance, work well with compression, by letting each device in the chain tame a part of the sound; or with reverb, where you can end up with more complex and individual acoustic environments by combining different aspects from each. Additionally, the software plug-in can be used in a way that’s less feasible with hardware, and that’s to keep adding multiple instances to each and every one of your playback channels. For most of us this would be prohibitively expensive to do with hardware, but it’s the perfect opportunity to let software plug-ins shine.

The most obvious examples are the proliferation of ‘console’ plug-ins that add some ‘flavour’ to your mixes. These will typically roll off the frequency response at low and high extremes, add a dash of benign harmonic distortion for added richness (particularly at the low end), and while the difference may be extremely subtle on a single channel, once added to every channel, the sonic difference is more pronounced. There are lots of such plugins on offer, many of which recreate the entire control set of famous console designs, complete with sections for EQ, compression and so on, while some also offer other analogue subtleties: such as small random variations in frequency response from one instance of a console channel EQ to another, to mimic the inevitable spread of electronic component values that you get in real-world circuitry. This randomness can ‘flesh out’ electronic sounds in particular, and such variations between the left and right channels of a stereo EQ will convert a straight down the middle mono centre signal into a more fleshed-out central mono mass.

Nevertheless, you don’t necessarily need all this functionality to explore the essential analogue console ‘sound’. If you want to dip your toe in the console waters without spending any money, why not download Airwindows’ Channel7 (www. airwindows.com/channel7), which offers a choice of three basic console types along with a drive control that morphs from perfectly clean, through very pure saturation, to more obvious fatness. I’ve mentioned Chris Johnson of Airwindows before in this column, because his plug-ins often achieve subtle yet beneficial results due to novel algorithms of his own design. He deliberately avoids the slavish modelling of real-world audio artefacts in favour of novel combinations of his own mathematical operations, and, as always, the truth of the algorithm is in the listening.

THE NEXT STAGE Another fascinating example from the Airwindows stable is the recent Interstage plug-in (www. airwindows.com/interstage), which aims to sound like running your audio through an ‘optimal analogue stage’. It offers no adjustable parameters at all, but performs its magic by reshaping the low end, similar to that of a capacitor-coupled circuit, while the highs runs into ‘active component electronic limits’, by ‘restricting treble slews based on the general amount of energy in the circuit’. Essentially you’ll hear no change if you don’t need what it’s doing, but Interstage will kick in when it detects excessively digital bass and treble in your audio, especially once audio levels are approaching 0dBFS. Once again, the results are subtle, but nevertheless fascinating, and when switching Interstage in and out blind, I’ve often found myself preferring it in circuit due to its goal of converting any overtly digital sounds into more analogue equivalents.

WINDING THINGS UP Another aspect of audio components that can add cumulative mojo is the sound of transformers, and in the plug-in arena I’ve been impressed by Kazrog’s True Iron plug-in (kazrog.com), which models the euphonic effects of audio transformers. Unless you push the parameters quite hard for special saturated effects, the results are again very subtle, yet once again if you add a single instance of True Iron on each of your playback channels the cumulative results slowly build into a warm roundness that fits beautifully with many musical genres. True Iron can also knock the perfect edges off clean softsynth sounds for a little more grit and attitude.

One important aspect with all cumulative plugin use is to be careful about gain-staging. All the euphonic effects described in this column will vary considerably with input level, so it’s important to spend some time discovering the ‘sweet spots’. After all, we’re only looking for subtle changes for each instance. I don’t necessarily add exactly the same treatment to every channel either, as some (bass instruments and drums for instance) may benefit from more transformer warmth, while others blossom with console tweaks. It can be a good idea, once you’ve got everything as you want, to render the song, then temporarily deactivate all the mojo plug-ins and render it again, so you can hear the difference properly and get your ears more finely attuned to these ‘analogue improvements’.