review menu



Acoustic Improvements of a Listening Room
Room Acoustics Products by Svanå Miljöteknik

By Robin Lybeck

Highend audio is in many ways an idiosyncratic hobby. After years of investing in source components, amplifiers and speakers, many audiophiles find themselves endlessly tweaking their systems and purchasing all kinds of products along the way. Racks, mains cables, vibration-reducing feet etc. find their home in almost every system at one point or another. Surprisingly enough, one major improvement is often overlooked; acoustics. True, many "serious" audiophiles do invest in acoustics, but arguably, many listening rooms show an underinvestment in this area.

The underinvestment in acoustics is certainly something I found myself guilty of during the early years of this hobby, but have since then strived to correct. In essence, the first possibility of really improving acoustics came three years ago, when we moved into our present house and I got my separate listening room.

At first, the measures were integrated with the furniture (bookshelves, rugs etc.) but my first “real” encounter with professional acoustic treatments came with the purchase of four ABCyll semi-cylindrical tube trap –absorbers (effective from 125 to 500Hz) from Swedish manufacturer Svanå Miljöteknik ( Once again, the link to this company was found by accident through the excellent Swedish audio website

About Svanå

Svanå Miljöteknik is based in Stockholm, Sweden, where it’s been active for the last 10 years. All products are finished in-house or at Herrljunga Träindustri, a company specializing in the manufacturing of wooden products.

Matts Odemalm, an engineer with a degree in acoustics, is the owner and chief architect at Svanå. Even though he’s responsible for the final planning and design of all products, Svanå develops much of their products together with professional studios around Sweden. To an increasing degree, Svanå also develops products for in-home use, making the acoustics less intrusive on a “standard” home interior.

The room improves…

I used the first four ABCyll-absorbers to dampen first reflections on the side walls from my Dunlavy SC-IV´s, one trap at the primary reflection point on the side wall and one at the secondary reflection point. The result was, of course, immediately recognisable. I could hear a clear improvement in focus, clarity, soundstage depth and a slight improvement in upper bass tightness. So I stayed with this combination for a while, even though I noticed a decrease in top-end sparkle and transparency (Dunlavy isn’t quite up there with the best in those areas to start with).

It was only when my present reference speakers, the PBN Audio Montana EPS arrived, that the overly dampened top-end started bothering me. Immediately upon arrival, I noticed that the Custom ScanSpeak Revelator used in the EPS could reveal huge amounts of top-end detail and nuance, but that my acoustics weren’t quite right for the speaker. So after talking with the always very helpful Matts from Svanå, I placed an order for a larger amount of material:

V-4 tuneable Helmholz absorber: The V-4 is a large, well-finished, Helmholz-type resonator with nicely rounded edges and a gap running the entire length of the front. The width of this gap can be altered with the aid of two standard screws, giving an excellent opportunity to find the exact in-room operating frequency for the V-4. The V-4 measures 48cm (w) x 48(d) x 112(h) and can be ordered in most colours. The effective range of absorption, based on the tuning, is between 45 and 100 Hz. Matts tells me that when any given frequency is chosen, the V-4 will offer absorption over a range of +/- 10Hz from this point. I ordered two for my 20sqm listening room. I would absolutely have ordered four (especially after hearing the result of two V-4´s), but I simply didn’t have the space.

V-4 (picture by SMT AB)

Golden Horn Diffusor panels: The GH is essentially a diffusor within a diffusor. Built from plastic, the GH contains a number of “bars” of seemingly random length, much like a traditional Skyline®-diffusor. The special thing with the GH is the fact that on the top of each “bar”, there is another irregular surface, with seemingly random “pits”, which makes the GH hugely effective over a very wide frequency range. The size of a GH-module is 55 x 55cm, and it is effective from 900 to 16000Hz. I used four on each side wall, giving very effective diffusion of first reflections.

Golden Horn (picture by SMT AB)

AD40 Diffusor panel: The AD40 is a diffusor panel containing a combination of semi-cylindrical shapes and wells with variable depth. Available in a large variety of sizes, the most common is a 20 cm (w) x 9(d) x 240(h) pillar, but Svanå will cut the pillars to any desired length. The effective frequency range of the AD40 is 1000-15000Hz. In my room, I had the back wall partially covered with AD40, covering roughly 3sqm in total.

AD40 (picture by SMT AB)

AD20 Creation Panel: Basically a more shallow version of the AD40, the Creation panel consists of 20 x 20cm panel “pieces” fit together at 90-degree angles to form a surface with great variance. The Creation panel can be built from any of the AD-elements, the elements with greater depth giving a more extended frequency range. I included a 60cm (h) x 120(w) panel as part of the back wall treatment.

AD20 (picture by SMT AB)

So with all products installed, my room contained four ABCyll-absorbers, two V-4 absorbers, eight Golden Horn-diffusors, three square meters of AD40 panel and an AD20 Creation Panel. These were backed up by a large wall-mounted bookshelf with irregularly stacked books and a large rug on the floor. You might think that the room looked like an amateur studio at the end of all this, but to Svanå´s credit I must say even I was surprised to see the high-quality elements actually enhancing the visuals of the room. While waiting for the Svanå products to arrive I actually built two large QRD-diffusors for use in the ceiling. Even though I was quite satisfied with how they turned out, they really couldn’t compete with the professionally finished products from Svanå. But most importantly; what did all this stuff do to the room sonically?


After waiting for the products to arrive and after installing them, I must admit I had fairly high expectations regarding the improvement in overall sound quality. I wasn’t disappointed. The change was as dramatic as it was enjoyable. It took me a while to tune the V-4´s and find the optimal place for them (not surprisingly, stacked in the corner behind the system), but once that was done I could enter a whole new realm of sound reproduction….

It really doesn’t make any sense to go into detailed descriptions of how different songs and records sounded before and after the acoustical installations, as the overall sum of musical “wholeness” was far greater than the separate parts.

The first thing I immediately noticed was the improvement in top-end extension and soundstaging. Compared to the earlier setup, when I used absorbers at the first reflection points, the top-end was significantly more transparent and alive. Cymbals would shimmer and slowly fade, instead of vanishing abruptly and getting covered by the other musical elements as before. Perception of top-end detail was also greatly improved. The soundstage grew beyond the speakers in the lateral plane, a completely new phenomenon in my room, while at the same time gaining significantly more depth. I’ll have to attribute this to the improved diffusion of first side- and rear-wall reflections (by the GH-modules and the AD-40/AD20 –panels).

In-room bass response felt remarkably unaltered at first, but once I found the correct tuning for the V-4´s I also found I could alter my speaker placement significantly from the former “optimal spots”. This resulted in the speakers being placed 40cm further away from the rear wall than before, dramatically improving soundstage depth and transparency. After this the bass response improved considerably. Using a Radio Shack® dB-meter, I was able to measure the more obvious benefits of my new arrangement. Sure, the RadioShack® –meter is far from being absolutely accurate, but the results can be compared to previous measurements using the same meter. Previously I had problems with dips in the in-room bass response, a result of our house being built on a wooden frame. The worst dip was almost -20dB at 55-60Hz regardless of how I chose to place my speakers. With the help of the V-4´s and the new speaker placement, I was able to achieve a +/-6dB response (!) from 20-120Hz, which obviously also yielded some very audible improvements.

The corrected bass response gave much more “weight” to the music, with bass drums and contrabasses getting the pressure they rightfully deserve. At the same time, the low end gained more definition and even the lowest octave became more pronounced than before (if the material mandated it). On dynamic peaks, the bass would remain tight and focused, while at the same time providing all the impact required. Combined with the ABCyll-absorbers in the other corner of the room, the bass quality improved beyond any previous comparison in my room, regardless of speakers or setup.

My system already had something of a pronounced midrange, perhaps a result of the dip in the low-end. Also, the Montana EPS has an extremely detailed and dynamic midrange-reproduction, which often proves “challenging” for bad recordings. After the installation of the Svanå-products, the midrange became more integrated with the rest of the music without losing any detail or transparency. On the contrary, detail was even improved on good recordings and combined with the increase in focus and soundstage depth, the overall “realism” was much improved.


As stated before, I had quite high expectations for the products from Svanå. They had received very positive feedback from various forums and the product range seemed to contain solutions for every problem. When the stuff finally arrived and was installed, the result really had been worth the wait.

At a total (approximate) price of over 5000€ (prices per element below), the acoustic treatment wasn’t all that cheap, but given the significant improvement in overall sound I would still call it one of the best price/performance-ratio investments I’ve made. The products are nicely finished, the shipping works (if a bit late) and Matts at Svanå is always ready to give advice on how to handle the installations. Also, the overall price is very attractive compared to many other alternative solutions.

The most obvious alternative for improving acoustics in the listening room would be to start with a few elements, maybe for the first reflections, then consider adding other elements when possible. My guess is that once you hear the benefits of proper acoustic treatment, there really is no turning back. It really doesn’t make much sense to invest a fortune in equipment if the room sounds horrible, now does it? When planning my next listening room, I’ll know exactly how to prioritize. The products from Svanå have earned my warmest recommendations.

Associated equipment

Cd-player: Audionet ART V2
Preamp: Audionet PRE I G2 with Audionet EPS power source.
Power Amp: Audionet AMP II G2 monoblocks
Speakers: PBN Audio Montana EPS.
Interconnects: Siltech SQ-80 G3 (cd-preamp), Siltech ST-48 G3 (pre-power amp).
Speaker cable: Analysis Plus Crystal Oval 8 (biwire)
Mains cable: Siltech SPO-18MF, Supra LoRad, Isotek Optimum with Furutech-connectors.
Mains filter/distributor: Siltech Octopus with SPO-20 mains cable. Isotek Orion mains filter.
Equipment stand: Finite Elemente Spider, with Ceraball-set under cd-player. Power amps placed on granite plates resting on a heavy wooden board, which is supported by Soundcare Superspikes. Finite Elemente Ceraball under monoblocks.
Room: ~20 Square meters. House construction: wooden frame, tile outer wall. Excellent bass absorption, no significant room resonance under 100Hz (measured).
Room treatments: Large bookshelf covers entire wall behind speakers. Heavy rug on the floor between the speakers and the listening spot. No TV or screen between the speakers, projector screen (96” Da-Lite) ceiling-mounted and retracted during all listening sessions.
Special acoustic treatments:
2x Svanå Miljöteknik (SMT) V4 Helmholz-type resonators in corners behind speakers

8x SMT "Golden Horn" diffusor panels at first reflection points (each. 55x55cm, 4 per side wall)

4x SMT ABCyll - tube traps in rear corners. Absorption down to ~125Hz

SMT AD40 and AD20 diffusor panels covering wall behind listening seat for a total of 3,6 square meters

Products & prices

All product data, sizes and pictures can be found at Delivery times should be agreed upon with Svanå.

Approximate €-prices w/o shipping (VAT 0%):

ABCyll absorber: (no longer in production)
Golden Horn diffusor panel: 90€ / unit (55c55cm, 120mm deep)
V-4 resonator: 160€ / unit
AD40 diffusor panel: 1500€ / sqm
AD 20 ornament (diffusor) panel: 1000€ / sqm