Rosson Audio Design RAD-0 Review

Sound Classics – Bass

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The RAD-0’s low end is impressive in single ended mode and very impressive in balanced mode. You get a perfect mix end of quality and pleasure. It may not be the typical neutral kind of bass because of the elevation, but it does sound really great.

Bass always is full bodied and it comes delivered with impact and punch. The depth and layering is very good and the RAD-0 has no issue with sub bass presence.  Single ended bass is a bit faster and tighter, but the balanced bass reaches deeper with more presence and better layering.

Sound Classics – Mids

Just like the bass, the mids are full bodied and connect perfectly to the bass. Mids aren’t overly thick but they’re always present, in-line with the bass presentation. The mids are smooth and have a nice hint of warmth, but they’re also spacious and well layered. The mid timbre here is something special and all this combined with the excellent separation and dynamics probably make this the most impressive part of the RAD-0. The vocals in the RAD-0 sound natural and they blend in perfectly, not showing up too much in front.

Sound Classics – Treble

I’ve tried not to make too many references to Audeze headphones but in this case I have to as this for me is where the RAD-0 really does it for me where Audeze has kind of always left me wanting something.

For an orthodynamic headphone the treble section is impressive. It’s clear, airy, extended and energetic, yet the presentation comes over as sweet and natural. The RAD-0’s treble is dynamic and lively, but especially the extension here is really impressive.

Treble also matches the smoother mids and full bodied bass perfectly, delivering a very balanced, high performing headphone.

Sources / Amplification

With its 29Ω and 98dB SPL, the specs tell us that he RAD-0’s rating is quite efficient for a full-sized ortho. That being said, it still is a full sized, high end headphone and most of them like a good amount of power (voltage/current) and unless you have a DAP like the AK KANN CUBE or the Luxury & Precision LP6, I advise you to power it by a good, powerful desktop amp ad the RAD-0 will really profit from it.

Portable Amplification

Luxury & Precision LP6 which we reviewed only a few weeks ago, was built to drive full sized headphones and it does an excellent job powering the RAD-0. If you read the LP6 review you will know I described the LP6 as being one of the best sounding DAPs in the world, and it sounds heavenly with the RAD-0 in balanced mode (4.4mm). This actually is one of my favourite combos when listening to the RAD-0 as you get a sublime sound, with a high technical level and timbre to die for. Bass is full, deep, layered. Mids are smooth, spacious, deep and treble energetic, extended and softly energetic. Everything in this combo works, it’s an end game setup. In single ended mode the RAD-0 still sounds very good, with a faster delivery and less body. The smoothness and level of musicality here is lower, the (bass and mid) body lighter and the presentation becomes more intimate. In SE mode you still get the great depth and precision but the presentation is less big, warm and romantic.

The Astell&Kern AK KANN CUBE is another DAP built to drive full sized headphones but it’s very different from the LP6. While the quality of the sound is good, you here can easily hear this is a DAP powering the headphones. You get less clarity and precision though the body, depth and layering are there. Technically it actually performs well, but not art the level of the LP6 or the desktop amps. Especially vocals, upper mids and treble here leave me wanting for more, and then I’m especially thinking of cleanness, energy and top extension.

One of my favourite portable units ever is the Chord Electronics Hugo 2 which I have been using a lot with the HEDD headphone. With the orthodynamic RAD-0 it sounds good, but not as good as with a desktop amp or even the L&P LP6. Something with this combo doesn’t sound right to me. You get bigg bass which isn’t the tightest and the vocals are more upfront. The treble section is not the best when it comes to clarity, extension or energy. The synergy here for me isn’t here. Sorry Chord!

With the Earmen TR-Amp DAC/AMP the result is better and the vocals and treble are presented with more energy and extension. You get a full bodied sound from bass to treble, with very good depth and layering. Bass is full, reaches low and is well layered (yet not the tightest). The mids are smooth, have great timbre, spaciousness and excellent depth. This little amp ($279) performs really well with the RAD-0, a nice surprise. That being said, compared to the desktop amps the precision and basically all the technicalities are lower but for the price this is impressive, especially seeing the synergy with the do-it-all Hugo 2 isn’t as good.

Desktop amplification

As stated, most of the descriptions on sound have been done with the Niimbus Audio US4+ amplifier, combined with the Violectric V850 DAC. I do advise to use a clean, precise and clear/neutral DAC with these headphones to make sure the input is optimal. Here are some other amplifiers we really liked the RAD-0 with:

The Lafigaro 339 is a dual mono OTL design but it actually works well with planar magnetic headphones. In single ended mode the RAD-0 sounds quite fast with lighter amount of body from bass to treble. The vocals in this combo are somewhat more up to the front. This combo probably doesn’t score best when it comes to extension and technicalities, but the speed and energy are mesmerizing.

The Atlas from Flux Lab Acoustics on the other hand scores incredibly high when it comes to technicalities. In single ended mode you get great speed, clarity and precision with excellent separation. The amount of body is more neutral and bass and mids sound more reference. Especially the layering here is impressive, together with the treble extension and liveliness. In balanced mode you get a bigger and fuller bass and mid section, with a sweeter, slower, yet more romantic presentation. Most impressive here is the bass depth and the layering. I like both outputs with this amplifier.

The same story more or less goes for the Auris Audio Nirvana. In balanced mode you get really impressive bass with great depth and layering. The mids are rich, smooth and spacious with gorgeous vocals, while treble is extended and smoothly musical, yet energetic. For some the amount of bass and mid body might be a little much in balanced mode, but in that case the single ended output is the one for you. Here you get a faster, lighter sound but it isn’t as spacious, wide and extended as before. You do get a more balanced and faster RAD-0 with improved clarity, especially noticeable in the upper mids and vocals. On this amplifier, I kind of prefer the single ended output as it already carries enough smoothness and timbre from the lovely tubes.

The Feliks Audio Euforia Anniversary Edition is another amp which makes the RAD-0 sound divine. The single ended output delivers good speed and tightness, but also good body and spaciousness. The Euforia AE and RAD-0 combo scores well when it comes to technicalities but it at the same time remains musical with a rich and smooth, yet clear presentation. A wonderful combo.

The part on sound continues on the fourth page with comparisons and our conclusion. Click HERE.