PSI Audio AVAA C214 Active Bass Traps
REFERENCE AUDIO – WITHAM ESSEX
BOB’s Review Series - No 92 – PSI AUDIO ACTIVE DIGITAL BASS TRAPS AVAA C214
INTRODUCTION
The C214 are active bass traps designed and manufactured by PSI Audio in Switzerland. AVAA stands for Active Velocity Acoustic Absorber, any the wiser? No nor am I but let’s have a listen to what they can do. Will they be the audio nirvana that other reviewers and users have reported, or will I find differently?
These 214 are perhaps smaller than you might think looking at pictures, they are cylindrical in shape measuring 640mm in length and 210mm in diameter and are deceptively heavy at 15kg each. They can be located as free standing vertically columns, but they can also be purchased with a fixing bracket to hang them from walls or ceilings or even laid flat on the floor. They cost £2,999 each, the fixing brackets are around £185 each. They come in matte black or white, my review pair are white and visually disappear into the room corners.
Although you can buy them individually it seems that two is probably the minimum investment to get the best from them and from your listening room. That means spending almost six grand to get set up and running, more than most might want to spend on a pair of devices that have no physical or electrical connection you your stereo or cinema system and cost more than many very decent amplifiers or speakers.
They are designed to actively eliminate excess bass resonances from your listening room and operate between 15 to 160Hz working only in real time using built-in microphones, drivers, and electronics to absorb room mode resonances in an area approximately 1.5m around them. The only set up required is to plug them into a mains wall socket, position them in your room and sit back and enjoy. No calibration is required but there is a couple of small buttons on the rear panel that adjust the gain. There is also a web based remote control facility via a PSI App that provides more user adjustments, and I will have more to say on this later. It’s important to note that the AVVA C214 Traps do not use noise cancelling technology, they are purely bass absorption devices with an active internal membrane and drivers designed to absorb room generated bass frequencies. No sound is emitted by the AVAA C214 traps (see below) and they don’t sit in the signal path being entirely independent of your audio system. PSI say they have designed them for ‘both professional studios and audiophile spaces where space and performance are equally critical. This results in dramatically improved bass clarity, faster decay times, and tighter imaging—comparable to the effect of passive absorbers many times their size’.
LOCATIONS
Your listening room can and will have a significant effect on the sound you hear from your system and no amount of room treatment can fully eliminate the effect the room has on the sound and in some ways that is a good thing. What the room can contribute to listening pleasure is much of the reverberation that gives your brain those important signals that provide essential spatial information and imaging that you definitely don’t want to eliminate. If you have ever had the opportunity to stand inside an anechoic chamber you will understand why those reverberations are essential to our understanding of space and location. Everything in your listening room including the system itself will have some effect on the way the room produces sound and those low frequency sounds are the most difficult to manage because the length of low frequency soundwaves is such that they rarely fully form in most average sized rooms. Bass frequencies of 40Hz have a length of around 8.5m to fully form a single cycle, a 20Hz wave requires more than 18m to fully form and this means that they bounce back before they complete a single cycle causing bass cancellation, blurring, booming and create room nodes where sounds are boosted or cancelled. These bass frequencies are generally most onerous in the corners of the room where they can be reflected, reinforced and amplified many times. Most sub-woofer manufacturers recommend taking advantage of corner reflections to boost bass generation by locating their subs in corners.
Low frequencies are difficult to manage with traditional wall and ceiling mounted absorption and dispersion materials and methods, simply because of the thickness of material that is needed, so a compromise is always the best one can aim for when using these traditional methods. Mid and High frequencies can be easier to control with traditional room treatment methods because they can be absorbed more easily and with thinner panels. Furniture and wall coverings play a big part here. Modern DSP control has reached the point where it can have a significant part to play in treating room acoustics, especially those low frequencies and are especially effective in AV cinema set ups. Not everyone however can use a DSP solution in their home system because most traditional stereo amplifiers don’t tend to have DSP capability on offer and in any event do you really want DSP mucking around with your carefully set up stereo system. DSP tools such as Dirac generally need specialist knowledge to set up correctly and it can be a time consuming and expensive exercise that is then susceptible to any change you make to the room environment or to your system requiring resetting the DSP.
The AVAA C214 Bass Traps use digital DSP to control their internal diaphragms and drivers to absorb the lower frequencies between 14 and 160H and they do this automatically. No user setup is required at the time of installation or at any time thereafter apart from choice of location and gain settings and because they are not physically connected in any way to your system their use of DSP seems more acceptable.
WHY TWO APPS
PSI have developed a web-based app to help control their AVAA C214 bass traps and rather confusingly there are two Apps that seem to work together to get the C214s connected to your wi-fi and to enable further user adjustability including remote on/off, firmware updates and gain settings. You can only place the C214 into standby mode via the remote app, manually your choices are simply on or off, standby is not a manual option. These apps work with IOS or Android. Clearly using the Apps does have a benefit. One of the Apps is called AVAA and the other is called PSI and I still don’t know why two different apps are required and more importantly neither of them worked for me.
After many attempts to connect the C241s to my network I gave up trying because no matter what I tried I just couldn’t get the Apps to recognise them on my network. When trying to set up a network connection the App says you need to have a 2.4GHz wi-fi connection, my BT Home hub has both 2.4 and 5GHz bands and even though I temporarily disabled the 5GHz one it made no difference, they simply wouldn’t connect.
After many attempts I did get the AVAA app to recognise each bass trap by scanning the QR code on the rear of each speaker and this did then allow me to set the volume remotely but none of the more detailed user adjustments that PSI Audio show on their website were ever available to me. Interestingly their user manual / instructions which I had to download say nothing about the need to scan QR codes. Perhaps it’s just my incompetence that prevented me getting the Apps to work and I can’t find anyone else who has had this problem. I would however suggest that PSI Audio need to clarify their instructions on how to make a wi-fi connection and further explain why they have two different Apps for this purpose, the manual is less than clear on this issue.
Hay-Ho, manual it is then.
SET UP AND LOCATION
You can tell if they are in manual mode because the small LED on the front turns solid green, it would be blue if a remote connection was successful. Gain can be set manually by pressing the small red and blue buttons on the back of each unit to turn gain up or down in an 11 stage range suggested by PSI from -12dB to +6dB. You can tell which setting has been selected by the colour of the LED on the rear panel which lights temporarily. As I was limited to manual mode, I found that only 4 different gain settings were available. Eventually via the scanned QR code I was able to set the gain remotely and chose +4.5 dB for each C214.
It is more than possible to use multiple C214s in your listening room to good effect but generally they seem to be used in pairs or multiple pairs because they are limited to absorbing low frequencies in a radius of just 1.5m around them so having one in each corner behind your main speakers seems to be the best way forward as a starting point, and that’s how I used them for this review.
I know from experience that my rectangular room has a combination of resonances or room modes relating to my room dimension. This means I have mode resonances at 27Hz, 43Hz and 70Hz related to the length, width and height of my room and with multiples of each such as 54, 86 and 140Hz etc. It is at these low frequencies that the C214s operate to absorb sounds, and by design they will have no effect of frequencies above 200Hz. Like other more conventional bass trap the AVAA C214 won’t completely eliminate bass modes but they will help to reduce them or smooth them, by as much as 6dB at some frequencies and in some rooms. Where the C214s score highly over more traditional methods of preventing room modes is in PSI’s own words ‘the AVAA should be able to cancel more modal bass per unit volume than passive bass traps can. And, as a result, it should get the job done in rooms where large arrays of bass traps are impractical’.
As noted above the best place to locate two of the C214s is in the front corners behind your main speakers in a stereo setup because these tend to be high pressure zones. This is where room modes are most prevalent and where the C214 can give the most benefit. In a cinema setup you might want one in all four corners of the room and perhaps at the first reflection point along the sidewalls, but this would be an expensive exercise and may only be appropriate in larger cinema setups or where installing large and extensive traditional bass absorbers is simply not practical.
Once you have plugged them in don’t expect them to make a sound as they are designed only to absorb sound, they can however make a deep reverberant waaaannng sound if you move or tilt them when they are turned on during setup as the internal diaphragms are jiggled before they settle down.
LISTENING
I read other reviews of the PSI AVAA C214 Bass Traps, and some say their effect is significant such that they can no longer live without them and others say their impact is subtle, I am firmly in the latter camp. Perhaps I’m fortunate that my listening room doesn’t have too many negative issues with room modes but switching them on and off didn’t bring about night and day changes to the quality of sound reproduction in my room. For the record I don’t have any form of acoustic treatment on the walls or ceiling of my listening room apart from two small thin GIK panels on the wall behind each speaker.
Noticeable differences with the AVAA Traps turned on was a tightening of the bass response with perhaps clearer bass reproduction not dissimilar to a lighter bass response. Bass was boomier when I turned them off again, but not by much. At first listen to the C214s it can be a little disconcerting because over time you subconsciously get to know what your room sounds like even though you likely won’t associate your system sound with room acoustics. But on that first turn on something was clearly different. Was that a good thing or a bad thing? Only an extended listen will inform you, but my immediate impression was that something was missing. Perhaps this is the very essence of what these AVAA C214 bass traps set out to achieve, you may like it, and you may not.
In any event with them in place and turned on you will probably not have heard your system sound like this before. I felt that most benefit was to be gained in freeing up of midrange and upper frequency responses than in improving bass response. This is probably because the mid and upper frequencies are now free of smothering room reverberations allowing them to sound cleaner and more composed as they no longer have to compete with a boomy room generated bass modes which have the effect of smearing the upper frequencies. Impressive results.
Towards the end of my time with the C214s I moved them from behind my speakers to the back wall behind my listening chair. I can’t say I could hear any difference with them on or off in that location but one of them clearly wasn’t happy with gain set at 4.5 and I had to turn it down to avoid it repeatedly emitting a weird waaaannng sound. At one point both C214s turned themselves off in this location, not sure why that happened but perhaps they were overloaded and turned off for protection. They clearly don’t like being moved and will often make that weird sound for a while until the internal electronics and drivers settle down again.
CONCLUSION
I’ve lived with my current listening room for more than 30 years, so I guess I know what to expect from it. When I first turned on the AVAA C214 bass traps I thought something was wrong with my system because it sounded so different. It takes time to understand what the C214s bring to the sound in your room but that doesn’t mean you can’t hear it straight away. Having listened to them repeatedly over the last week I now have a better understanding of what they can and can’t do in my listening room. They do bring a certain clarity and definition to the bass frequencies and even the mid and upper frequencies seem a little less restrained, but it’s a subtle difference at best and I’m not sure I liked what they do.
They are great space savers in any domestic setting and whilst I could never go down the traditional route of treating room acoustics with massive bass traps and panels stuck to the walls and ceiling, I’m equally not sure the AVAA C214 are the answer to any real or imagined problems I may have with my room. In your room however you might just find them to be just the answer you are looking or listening for.
At £3000 each these AVAA C214 bass traps are not cheap, especially when compared to the price of more traditional room acoustic treatments, but they are effective in the right setting and if you have or even just think you have problems with your room acoustics then these might be for you. They could be the perfect remedy for a problem you probably didn’t even know you had and are essentially a fit, set up once and forget solution to treating low frequency modes in your listening room.
It’s just a pity that I couldn’t get them to be fully recognised on my network, not just for convenience but mostly because I wasn’t able to check which firmware version they are using and to make those finer gain settings I think I needed.
During this review of the C214s in my home listening room it was clear that these active bass traps do indeed make a difference to how my room performs. Whether this is a good thing is probably up to the listener to decide. All other reviews I have read of these devices have been very positive but for me I couldn’t quite get over the feeling that they were (literally) sucking the life out of my music, everything was clear and precise, but I was missing some of the room reverberations that I have come to know so well over more than 30 years of listening in this room. You might disagree. Come and have a listen.
October 2025
Bob – Team Reference Audio