Five years. Not Ziggy Stardust’s apocalyptic warning but the time passed since I moved from Sydney to Berlin. Today is also five years to the day that I moved into the apartment in which I write this article. That also means I’ve spent five years listening to hi-fi gear in a room that I now see as the most important ‘component’ in any loudspeaker system placed within it. Like you, I hear music through the acoustic lens of my electronics, the acoustic lens of my loudspeakers and, most significantly, through the acoustic lens of my room. It’s why I think it important that reviewers show off their rooms even if those rooms are not acoustically perfect. Because no room is.
Upon first entering my Berlin apartment in November 2016, I clapped my hands in its empty lounge room to hear high-frequency reverb run amok; the long zinggggg in the echo’s tail told me something would need to be done before I could set up a hi-fi system. A room’s dimensions and its construction materials all feed into its sound. My lounge-listening room measures 6m x 5m and has a ceiling height of 2.8m. Large windows line one side ‘wall’. They make it easier to shoot videos using only natural light but bring with them the acoustic compromise of high sonic reflectivity. As do the room’s wooden floors, their 28cm concrete underlay plus similarly thick concrete walls and ceilings. During the past half-decade, I have taken steps – some big, some small – to minimise the room’s colouration.
I chose this apartment because it’s a Neubau (new building) made up of five floors of offices with split-level maisonette apartments lining the top two floors. If those offices stuck to the 9-5 (and they have!), there would be nobody below to disturb with music on evenings and weekends. Only one neighbour living on the other side of the front wall would need to be considered. In five years, not once has she or anyone else made a noise complaint. This is the opposite of most other apartments in the city. The majority – Altbau (old buildings) – come with the worry that even one’s footsteps are disturbing those living below. Why? Because they are disturbing those below. Expat-centric Facebook groups are littered with tales of Altbau-residents suffering ‘loud’ music coming through the ceiling; or distraught that they themselves have been deemed the source of excessive noise. Wafer-thin floor-ceiling scenes like this pull the brakes on all but very low volumes for music playback. Subwoofers? Fuggedaboudit.
Sat in front of a pair of loudspeakers, we hear their direct sound but also the reflected sound coming off walls, windows, ceiling and floor aka echo. That reflected sound is always late, delayed by milliseconds. In the worst of cases, it is delayed by whole seconds. What I was hearing in my empty Neubau space was the sound of high-frequency reflections pinging around the room. Loudspeakers don’t just radiate sound left and right but up and down; the lower the frequency the more omni-directional their radiation pattern. And reverb isn’t only a high-frequency problem. Reflected/delayed sound at any frequency can smear music’s finer details and blur instrument placement to rob the soundstage’s stereophonic illusion of its player outlines.
Reverberation is also why many YouTubers believe that videos of a hi-fi product’s ‘sound’ are pointless. When we’re in a room and listening to music, our brain will automatically try to separate the sound arriving directly at the ear from the loudspeakers from the reflected sound coming off walls, floor and ceiling. How much do we subconsciously filter out? Here’s a little experiment you can try at home: record yourself talking from your listening position with the microphone placed on the loudspeaker plane. Now listen to the recording through a pair of headphones. Sounds awful, right? Now you’re hearing the room reverb that your brain filters out but the microphone does not. Putting it another way, with sufficient distance between me and my mic, a recording of me talking in my room will sound more reverberant than if you were here, sitting the same distance from me.
However, trying to talk to someone on the other side of an indoor swimming pool reminds us that there is a limit to how much our grey matter can filter out. Reverb can give us a sense of how large a space is, even if the lights are out! Hopefully, they are always on where you swim.
I’m a minimalist at heart. I don’t enjoy being surrounded by too much stuff or an excess of clutter. I like my living spaces to have a clean look. Unfortunately for the audiophile, minimalism sits at odds with getting good sound from a loudspeaker system. A room with hardwood floors and bright white walls looks wonderful but most will sound plain awful.
We must minimise the square meter-age of hard surfaces if we wish to dial down the room’s reverb. Hardwood floors, as attractive as they are, scream out for rugs to reduce some of their reflectivity. The thicker the rug, the lower the frequency absorption. On the walls, we might hang ‘professional’ acoustic absorbers or – at the very least – break up the space with picture frames and bookshelves.
Know, however, that such basic measures will do almost nothing for low-frequency problems. A 40Hz tone has a wavelength of around 8.5 meters; 50Hz runs 6.9meters; 60Hz, 5.7m. Soundwaves that run to meters laugh in the face of the little black foam squares favoured by bedroom DJs and producers, which look the part but rarely sound it. I know: I used the audiophile equivalent – a piece of slitted plywood mounted to a black foam square – for a number of years.
From Wikipedia: “As a rule of thumb, sound travels at one foot per millisecond (344 m/s), so the wavelength of notes at 1 kHz is about a foot (344 mm), and at 10 kHz about an inch (34 mm). Even six inches of glass fibre has little effect at 100 Hz, where a quarter wavelength is over 2 feet (860 mm), and so adding absorbent material has virtually no effect in the lower bass region in the 20–50 Hz region, though it can bring about great improvement in the upper bass region above 100 Hz.”
A week after moving into my Berlin pad, I put down three of IKEA’s largest rugs to cover 75% of the floor. Hanging some very basic acoustic panels on the walls and then loading in a couch, a second chair and some IKEA Kallax filled with vinyl records took the high-frequency reverb from a 5-g zingggggg to a 4-g: zingggg. Couches and other similarly-heavy soft furnishings can do more for high-frequency absorption than the aforementioned black foam squares.
One surprising acoustic improvement to my room’s high-frequency behaviour came from lining up IKEA Gnedby CD towers in a 1-2-2 configuration along the rear wall. CDs and their plastic cases don’t absorb high frequencies – they scatter them. This is called diffusion.
Clapping my hands again after a year in the new pad – more furniture, more vinyl, more CDs – told me that what was once a 5-g zinggggg had become a 3-g zinggg. And, of course, these improvements could also be heard when listening to music through a loudspeaker system. The near field listening setup that I had started out with – one that turns down the negative influence of reflected sound – could be expanded to accommodate a greater distance between listener and loudspeaker.
All set? Not by a long shot.
The start of 2019 would bring with it a bass bombshell. Dutch & Dutch’s Martin Mesink had visited Darko HQ to set up his 8c streaming active loudspeakers. The Dutchman’s REW + microphone analysis exposed a 35Hz room node (and much less severe 70Hz mode) that could be heard contributing to bass build-up in the front left and rear right corners, and bass suck-outs in the front right and rear left. My preference for standmount loudspeakers whose natural bass roll-off begins north of 40Hz had – until now – kept this 35Hz issue from view. With the 8c capable of playing full-range (down to 20Hz), their internal DSP-powered room compensation smarts moved from ‘nice-to-have extra’ to ‘essential tool’. It’s why Kii Audio quite rightly promotes its Three’s (+ BXT) cardioid-shaped low-frequency radiation pattern as instrumental to their room agnosticism.
With 8c coverage bagged and tagged and one eye on future subwoofer deployment, I turned to GIK Acoustics for help with my room’s 35Hz mode. They would supply a set of eight Tuned Membrane bass traps for placement in the two (diametrically opposed) corners where standing waves were most easily heard. I would also option a quad of GIK’s 2A Alpha Pro absorber/diffusor panels for front- and side- walls. Towering the bass traps four high proved visually unsightly even with each one front-plated by GIK’s Impression Series designs. The bass traps were subsequently collapsed into four pairs of one stacked atop another: one pair in the front left corner and the other six forming an L-shape in the rear right. This was a sharp lesson in how dealing with a room’s bass problems passively introduces a good deal of physical intrusion. Few households would entertain even a single 60cm x 60cm x 33cm bass trap, let alone eight.
Why can’t room correction software like Dirac or Lyngdorf’s RoomPerfect be used to tackle a room’s acoustic issues and skip out on the hanging of acoustic panels? Perhaps the answer lies somewhere in the language. These aren’t room correction devices but room compensation devices: a microphone talks to a DSP ‘brain’ to build an acoustic map of the room in order to adjust what comes out of the loudspeakers accordingly. In my room, that means a reduction in 35Hz energy coming from the loudspeakers. But what of high-frequency reverb and early reflections? Room compensating DSP can only do so much.
I know this from running RoomPerfect on a pair of Vivid Audio Kaya S12 once my lounge-listening room had been stripped of its furniture to leave nothing but the loudspeakers and a Lyngdorf TDAI-1120. Sound quality was improved slightly by RoomPerfect’s application but the room’s reverb and reflectivity remained strong. I liken this to icing a burnt cake. RoomPerfect’s icing renders the final result more palatable but it cannot mask the issues that lie beneath. A burnt cake tastes like burnt cake, icing or not.
The reason for my stripping the room of its furniture (sideboard excepted) brings us to last week: Portugal’s Vicoustic was all set to give my room a complete acoustic makeover. Out would go GIK’s bass traps and absorption/diffusion panels and in would come a soup-to-nuts overhaul similar to those seen – and heard – in professional recording and mastering studios.
This bespoke room treatment has been four years in the making. The plan was first hatched in 2017 during a visit to Audio Plus Service – the Portuguese company’s Stateside distributor – at Rocky Mountain Audio Fest. Vicoustic would spec out and install a full acoustic treatment and we would film the installation process. Unfortunately, personnel changes at Audio Plus Services during 2018 led to the project being iced until earlier this year when it was defrosted by Vicoustic’s German distributor Audio Reference GmbH (who would now handle the install).
The original plans were adapted slightly for reasons unknown but the intent remained the same:
- to reduce reverberation time to between 0.3s and 0.6s between 250Hz and 4kHz
- to reduce early reflections
- to act on room modes and flutter echoes e.g. 35Hz
According to Vicoustic, “The listener should be able to feel the ambiance and reverb contained in many recordings, therefore, early reflections from the listening room should be controlled in order to avoid masking that ambiance and reverb.”
This would be achieved by installing the following acoustic panels:
- Front wall: 4 x 60cm2 VicPattern Ultra Wavewood absorbers + 2 x 60cm x 120cm VicSpacer Plus absorber
- Side wall: same as front wall + 60cm x 120cm Multifuser Wood MKII diffuser
- Rear wall: 120cm2 Multifuser Wood MKII diffuser
- Ceiling: 8 x 60cm x 120cm VicSpacer Plus absorbers + 4 x 60cm2 Multifuser DC2 diffuser
- Front right and rear left corners: 3 x Super Bass Extreme Ultra
(Note: this differs from the 2018 room rendering shown above)
Vicoustic panel installation took place last Friday (12th November): 12 hours’ work for Audio Reference GmbH CEO Mansour Mamaghani and his offsider, Thomas, with only a 10-minute pause for lunch. Darko.Audio cameraman Olaf filmed snippets throughout the entire day, including some talky bits with yours truly. A YouTube video with more thoughts attached
will follow next week can be found here.
What that video won’t contain are my thoughts on the improvements to sound quality introduced by the Vicoustic makeover. We had only a lav mic at the end of the day to expose clear differences between the empty room with Vicoustic panels lining its three walls and ceiling and the untreated room we started with at 8:00am. I didn’t set up a hi-fi system until the morning after Thomas and Mansour had packed up their drills and ladders and driven back to Hamburg. Thomas took some low-frequency measurements with REW and a subwoofer but the ‘before’ and ‘after’ was, I believe, rendered invalid by a missing set of bass traps that left one of the two problematic corners untreated.
Hi-fi components arriving here for review treatment aren’t turned around in a matter of days. It takes weeks to give ’em the once over. And since there’s no easy way to return my room to its original state, first impressions on the Vicoustic overhaul must do the heavy lifting:
- The high-frequency reverb zing that plagued the room, even with GIK panels and heavy furniture in place, seems to have been eradicated
- Voices – especially male voices – are now conveyed with a richer tonality
- The soundstage between the speakers is now drawn a little further back from the loudspeaker plane and closer to the front wall
- Stereophonic specificity has been kicked up a notch
- Airy recordings now sound airier
- The room is still not perfect, and probably never will be, but it sounds noticeably better than it did before
I’ll be discussing these findings with Twittering Machines’ Michael Lavorgna in the next episode of the Darko.Audio podcast. If you’ve listened to our most recent episode, you’ll already know our thoughts on value perception at the high-end. Clocking up €10,000 parts and labour on the cash register up, this Vicoustic room treatment won’t be for everyone but — and this is the wallop for anyone still with me — it will have far more of an audible impact on sound quality than any €10K amplifier, DAC, phono stage, cartridge or network streamer.
Hold up! The room isn’t quite finished. The freestanding Super Bass Extreme Ultra bass trap destined for the rear right corner won’t arrive for another 2-3 weeks. I’ll also be switching out the white VicSpacer Plus wall absorbers to green. Aesthetics matter — and I remain surprised that this Vicoustic fit-out hasn’t turned my lounge room into a nerd zone. The front wall’s white panels are removable for when I wish to project movies.
And that brings us to the most significant implication of last week’s fit-out. With Vicoustic’s wall and ceiling panels now doing the heavy lifting on reverb and early reflection reduction, the need for sound-absorbing/diffusing furniture and floor coverings has been drastically reduced. One chair has already joined the CD collection on the upstairs landing and the rug closest to the front wall just said hello to the recycling bin. The other two rugs will soon follow suit and a new rug will eventually be placed between the couch and the loudspeakers.
Moreover, I see no need to return the hi-fi rack to the lounge room when the four sets of IKEA Kallax shelves that house my vinyl collection are all the extra bulk the room needs. Instead, the uppermost surface of each Kallax unit and the sideboard will be used in tandem with ISOAcoustics Zazen platforms to host amplifiers, DACs, phono stages and turntables. In other words, with full acoustic room treatment now on deck, I can return to my minimalist aspirations.
Of course, there remains more that could be done. Isn’t that always the case? Here, the glass is half full. No. Wait. Scratch that. With only rugs on the floor and acoustic curtains hanging on the window-side, four of this room’s six sides are professionally treated. That metaphorical glass is, in fact, two-thirds full.
Further information: Vicoustic
This story continues here.