AudioScape XL-305R

We all love a good spring reverb, but this one offers a much wider range of sounds than most.

AudioScape’s outboard gear has graced our pages a few times now, but their XL‑305R stands out as a much more creative toy than most devices in their range, most of which tend to replicate things like vintage preamps, EQs and compressors. Housed in a 2U steel 19‑inch rackmounting chassis, it is a recreation of a vintage device, but this time it’s a stereo spring reverb unit. The resulting creation fits a whopping 12 springs inside, plus an EQ section, and it’s very different from your average guitar‑amp reverb, in a good way: it’s not overstating things to say that it’s capable of a huge range of effects, including a plate‑like smooth and dense reverb.

Mimicking MicMix?

Its muse is a pretty quirky device that was, reportedly, invented almost by accident: the MicMix XL‑305 Master Room Reverb, which was released in the USA in 1979, not long before affordable digital reverbs started to displace such mechanical gadgets in studios around the world. Now, I love a good spring reverb, and like to think I have a good grasp on what they can do for a sound. As well as those in my various guitar amps and Hammond organ, I’ve used vintage studio models including the AKG BX20 and the Great British Spring, along with more esoteric modern units such as IGS Audio’s wonderful four‑channel Springtime. But I’ve never actually laid hands or ears on an original XL‑305. I know it very much by reputation, though, and was particularly keen to hear what AudioScape’s interpretation might offer.

What really made the XL‑305 stand out from the crowd is that its spring assembly’s 12 individual springs were tuned to mimic musical intervals, and the result is a sort of musical sustaining effect — one that its designer suggests sounds rather like “opening the lid of a piano, holding the damper open and singing into the strings”. Furthermore, it’s a two‑channel device, in which, by design, the channels aren’t the same. Notably, the ‘odd’ delay times are placed in the left side channel, and the ‘even’ ones are on the right, so as to create a full stereo image even when fed a mono source. Those two outputs can also be summed to mono, to create a much denser mono reverb effect if desired. So, as I say, it’s a very different proposition from most spring reverbs’ more random wash of reflections.

Four units each house three springs, giving the XL305R a total of 12 strings that make possible its musical tuning.

AudioScape say they started by replicating the original device, but “reimagined the rest of the design from the ground up”, a process that involved four years of R&D, working with the designer of the original MicMix unit Wayne Kirkwood, and performing extensive listening tests before settling on their preferred spring decay times. It seems to me, then, that this isn’t simply a case of cloning old hardware for commercial reasons, but rather it’s a labour of love. That’s an impression that is underscored by the fact that these units, which are built by hand in small production runs, are rationed to a maximum of two per customer... and, crucially, by the sound as well.

Springing Off

The glossy, black‑painted steel front panel hosts a pretty intuitive control set, with two rows of six knobs for each channel to give you 12 knobs in total. The leftmost one is a rotary pot to set the input gain, and this is joined by an LED to indicate overloads. Adjacent is a dry/wet mix knob, and the remainder are one‑knob EQ bands, each with a fixed frequency (150, 600, 2000 and 6000 Hz, respectively) and bandwidth (a fairly broad Q of around 1.3), a ±10dB range and a centre detent. The EQ stages are arranged in series.

A pair of switches, one for each channel, toggles between Parallel and Wet settings: this is a new feature, not found on the original units. In the Wet position, you have a fully wet signal and the mix knob effectively becomes an output level control. Set to Parallel and put the mix controls at their maximum wet position, and you’ll get a 50‑percent wet signal, so the mix control operates over a much more useful range if used as an insert effect. After the toggle switches are two backlit buttons, one labelled Mono Drive and the other Mono Return. When lit, the former links the channels together for stereo use, while the latter sums the two signal paths to give that denser mono reverb effect that I mentioned above.

Finally, we have output level metering, with one horizontal eight‑LED bar meter for each channel, and a larger toggle switch to power the unit on/off. Having not read the manual when I first tried this thing out, the meter threw me a little... As I said above, the two channels are different by design. Consequently, feeding the same input signal to both inputs and setting all controls identically results in different meter readings on each channel. If you plan on using this as two separate mono reverbs (which is perfectly possible), you might want to take time to audition which channel sounds best on which source.

The unit features a large, locking connector for the cable from the included external universal power supply.On the rear, there’s little to see. Just two XLR pairs for the balanced audio I/O and a locking connector for the external universal (120/240 V) switch‑mode PSU. Screws on either side of the case provide grounding points.

Lifting the lid mercifully requires the removal of only seven screws, and reveals another glossy black box that houses the springs and pickups. The pickups are really sensitive, so they and the ends of the springs are shielding by mu‑metal covers, and the whole, delicate assembly is suspended on four springs, which attach it to the outer case. For good measure, there’s foam packing to ensure unwanted movement is minimised when the case lid is screwed in place. The external controls and the I/O each sit on daughterboards behind the front/rear panels, and these connect via ribbon cables to a main PCB on the base of the unit, populated entirely with traditional through‑hole components — which should make servicing easy in years to come. Overall, the quality of construction, inside and out, seems good.

The business end of this reverb is hidden in a spring‑mounted black metal case (under a foam spacer that’s been removed for this photo), with the sensitive pickups shielded by mu‑metal from magnetic interference.

Sound Impressions

When the XL‑305R review unit arrived, I was working on a mix that lent itself to more creative reverb. Among other things, it featured male vocals, falsetto backing vocals, various acoustic and electric guitar parts, bass, drums, a Hammond B3 organ patch, and various delays, reverbs and modulation effects that I’d thrown into the mix already. I set the XL‑305 up as a stereo send effect, and then spent several hours putting it through its paces on the various different parts, just to see if it might bring anything useful to the party. Later, I tried it ‘offline’ on a wider range of material to test my first impressions.

Spring reverbs might not always ‘wow’ you, but there’s no denying that they have a distinctive charm, and there’s definitely just as much a place for them in modern productions as in vintage ones. But while there’s no mistaking the fact that this thing is a spring reverb, it’s completely unlike others I’ve used. Nothing like the ones in my Fender ‘The Twin’ or Blues Deville amps, for instance. You can certainly dial in a familiar‑sounding metallic wash, should you wish, and you get more of that character with hotter input levels. But even then, it all sounds much smoother, more coherent, more elegant... more musical. Nicer all round, really, as it generally sounds much more sympathetic to the source.

You can use it on vocals for a sound you wouldn’t normally dream of coaxing out of a spring reverb...

If you choose to dial back the input levels a bit, though, you’ll find that it can also deliver effects ranging from a thickening ambience, through more of a reverb chamber character, to longer, smoother, almost plate‑like decays. You can, for example, use it on vocals for a sound you wouldn’t normally dream of coaxing out of a spring reverb (some effects I dialled in wouldn’t sound out of place on a Lana Del Rey record). Still, it can just as easily be used to add dimension to less obvious targets, such as drums, or bass guitar, and I really enjoyed it as a mono insert, as a means of lending body and weight to a snare drum.

All of that already makes the XL‑305R officially A Good Thing, but you also have those EQ controls to bring into play (and, as discussed in the separate box, some fun sound‑design tricks to call in should you wish). I found the tone controls a godsend.

Yes, I realise you could patch in another equaliser or use any number of plug‑ins to sculpt the sound being fed into or coming out of this reverb. But remember what I said above: the input level makes such a difference to the character of this reverb, and it’s genuinely useful being able to reach out and make all your level changes and EQ moves in the one place. Thus, I found it super easy to tailor the reverb effect to suit the various different instruments in the mix I mentioned above, whether I wanted them to tuck the decay back in the mix to add a sense of depth while leaving the source bright and upfront, to place a bright reverb opposite an upfront guitar panned to one side, or to blend with the Hammond part that I’d already worked hard to get sitting further back in the soundstage.

AudioScape publish some technical specs, should you wish to look them up. But honestly, for the most part I don’t think they’re really worth concerning yourself with — you’d rarely turn to any spring reverb expecting ‘pristine and clean’, right? You’re looking purely for life and character. You might want to note that the input impedance is an old‑fashioned 600Ω, which some older consoles’ unbalanced inserts might struggle with (but most gear won’t). And the little crosstalk between channels doesn’t lessen the appeal. The bottom line is that you get that character in spades, without undue audible noise or, unless you deliberately cook the levels in search of it, distortion.

Verdict

Would I use this reverb on every mix? That’s a tough question to answer. I’d consider something like this to be an indulgence, for sure — after all, we have seemingly a million very capable reverb options in the box now (not least the plug‑in version of this one that AudioScape have developed!). But if I had one of these in my studio, I reckon I’d at least be trying it out on everything. It offers such a characterful, textural dimension that can sound really enticing — a richness and depth that’s truly seductive. And even with long tails, it just doesn’t seem to get in the way as often as typical spring reverbs do, so the chances of it bringing something useful to the table are that much greater. It would certainly see a lot more use than any other spring reverb I’ve used!