THE BIG DAY - STACK AUDIO AUVA 70s and 100s vs TOWNSHEND vs ISOACOUSTICS GAIA 1
(AUVA 100s on the ARKE Vaders)
I have been gathering my thoughts after the speaker isolation comparisons yesterday. It was a great day and really good to catch up with people. There were 5 of us present and we spent over 4 hours listening, changing over and listening again. The differences weren’t subtle and we were certainly surprised by the uplift provided by some options!
I have been considering isolation for my speakers for some time, but never committed for a few reasons: cost and some doubts regarding the principles underlying the 'usual suspects'. I used to work in the Aerospace industry so have a reasonable understanding of mechanics and vibration, however, I am certainly not an expert in vibrational mechanics!
The main brands with large market share are Townshends and IsoAcoustics - I have heard both at shows and on other people systems. Yes, they do make a difference and there is no doubt that they help to isolate the speakers from the room and the floor from the speakers. It seems they all manage this to varying degrees. Now, the rub! What bothers me about these solutions is cabinet movement and the degree to which they
actually damp cabinet vibrations. With GAIA demos I have always felt like they solved issues, but at the expense of others. Townshends have always worried me as we have a young daughter and I’m not a huge fan of my speakers wobbling about so freely. Although, I could certainly live with this if the SQ is the best against other competitors.
More recently I have become aware of some relatively new speaker isolation devices from Stack Audio. Stack Audio take a very different approach to IsoAcoustics and Townshend and this piqued my interest. Stack Audio are strong believers that the speakers should be firmly coupled to the floor and the cabinet should be rock solid. This resonates (no pun intended) with me as I strongly believe a cabinet should be as static as possible and very free from cabinet vibrations. I realise some manufactures choose to work with cabinet resonance and effectively embrace it within their voicing. This isn’t for me, I’d rather the cabinet was as inert as possible and give the drive units the best possible environment in which to reproduce the signal with minimum distortion and noise. Stack audio use a particle damping technology to dissipate vibrations at the speaker/floor interface. In principle, this sounds like the optimum solution: hold the cabinets rock solid AND absorb/dissipate excess vibration in the cabinet and travelling up from the floor. I must admit, to start I was a little sceptical as the AUVA 100s (the largest option) are pretty large, but would they absorb and dissipate enough of the extra energy? The 100s are just over 1.2kg and contain quite a lot of particles, but it is really enough? More on this later.
So, my speakers… They are based on a Troels Gravesen CNO4 design. They use SEAS Nextel 6.5” and 8” mid/bass drivers and a SEAS crescendo tweeter. They are underpinned by a 12” bass driver running active and driven by a 500w plate amp on each channel. I have redesigned the cabinets and spent some time trying to make them heavy, well damped and as inert as possible. I could’ve gone much further, but the speakers would have become way to heavy to take to demos. They are 65kg as is and have been split into two enclosures for easier handling. The top enclosure houses the tweeter and two mid/bass drivers, and the lower enclosure houses the 12” bass and plate amp. These speakers reach down to 20Hz at -6db and are pretty flat to 26Hz they go deep so will certainly be a test for any isolation.
Most reviews are by one person, but I wanted to get a range of views and get results from multiple comparisons over a longer period time. Whilst, a one person review can provide useful information and opinion, I want to test in multiple systems/rooms and with many subjects. This is, quite frankly, a logistical challenge! Fortunately, I have made bespoke speakers for quite a few people and know various people who are keen to join in with testing. Various people already have Townshend bars or Isoacoustic GAIAs so this is an ideal opportunity to test the Stack AUVAs in many locations against a few other options.
I have spent a few weeks trying to borrow a suite of devices to compare. I contacted Stack Audio, IsoAcoustics, Track Audio and Audite Acoustics. In addition, a client brought some Townshend bars to the comparisons in my demo room. Stack Audio and IsoAcoustics provided samples. Audite Acoustics were extremely helpful, but sadly had no Platforms available at reasonably short notice - I am hoping to test one of the Audite Phaenon platforms in the Autumn. Track Audio were contacted twice, but I received no response - this is a shame as their devices look beautifully engineered. IsoAcoustics provided some GAIA 1s which had the correct weight rating for my speakers. Stack Audio provided all AUVA options: 50s, 70s and 100s.
I won’t go into loads of details on the technology and philosophy behind each device. All of the manufacturers have plenty of information on their respective websites.
Aethetics, build and feel:All devices came in attractive packaging and all were manufactured to a high standard. I won’t go into loads of detail as this is available in plenty of reviews and I’d rather get into the nitty gritty of the listening. I will say that the Stack Audio AUVA 100s are pretty chunky and certainly have a visual presence under the speakers. All reviewers present preferred the look of the Townshends and GAIAs - the GAIAS were especially attractive in their gunmetal finish. The Stack AUVAs are beautifully made, but the 100s are certainly chunky - this is something of necessity for damping in the large speakers. One client, in particular, wasn’t taken with the look (of the AUVA 100s), so they’ll have to sound good to win some people over. I started to really appreciate the look of the AUVA 100s, but can appreciate why others may not.
Proceedings:
The Stack Audio AUVA 100s were already in situ under my speakers so we started with those. At this point, no one had a frame of reference, so they had to become acquainted with the system. Some readers may be wondering why we didn’t start with no isolation? This was the plan, however, it seems the AUVAs improve a little as they settle in. The Townshends and GAIAs need no settling time, so it only seemed fair to have to have the AUVAs fully on song. I realise some people will be rather surprised that the AUVAs need running in! ‘Running in an isolation device… that sounds like rubbish’ I hear many people exclaiming. Perhaps it is rubbish, but there was no harm in following the manufacturer's guidelines. I actually stumbled on the 'settling in' by mistake. The Stack AUVAs arrived about a week before the testing, so I was curious and fitted them. I was initially very impressed, but it was only days later that I seemed to be appreciating them more and more. The most likely explanation was that I was adjusting to the sound, so I just settled on this as justification. However, I mentioned this is passing to Stack Audio and they had experienced the same and advised the particles used for the vibration dissipation need to settle after installation. Other reviewers and Stack clients had reported the same. I know, I know, this sounds crazy! The only way I can explain it is with an analogy… If you fill a vessel with various sized small beads and then subject that vessel to vibration the beads will settle and reorganise themselves in the vessel. They will eventually settle and tend to settle to a minimum volume in the vessel. Before settling (with a more open structure) the beads will absorb vibration in a different manner to when the beads are fully settled. I do not know if this makes a difference, but it seemed prudent to ensure everything is ready for testing.
Another point of note is regarding the Townshend bars. They were not new and were well used. They looked in good condition and the rubber bellows (around the springs) did not look perished. I do, however, mention this as it is possible the Townshends were not at the their peak new performance. Unfortunately, this is only pair we had available.
The listening:
As explained above, the Stack Audio AUVA 100s started proceedings. It is hard to write much on the listening impressions as we had nothing else to compare to at this point. Next up were the Townshends and at this point we had two distinct presentations to comprehend. The difference in my room, on my speakers was frankly astounding! We tried 3 main tracks (all on vinyl) for comparisons (although various other tracks were tried at certain points):
Robbie Roberston - Somewhere down the crazy river: this was a favourite track of few people present and certainly worked extremely well for comparisons. Lots of layers in the mix and a really good production.
Dave Brubeck Quartet - Take Five (Analogue Productions Vinyl): Rather cliché and perhaps not a very adventurous choice! However, it’s a great track, great recording and everyone knows it.
Gogo Pengiun - Bardo: I really like Gogo Pengiun and find it a real test for a system and speakers. Some of their tracks have reasonably simple presentations, but Bardo is a very layered mix and the interplay of the double bass and drums is often intense and fast paced - most systems and speakers simply can’t keep up with this track.
The Stack AVUA 100s laid out all three tracks in a wonderfully deep, wide and high soundstage - nothing was left to the imagination and even very complex sections of the Gogo Penguin track were laid out in breath-taking clarity. The dynamics and attack were impressive. At the start of Bardo the double bass begins and the plucks were presented with real body and attack. Not long after, the pianist strikes the keys with real intensity - the attack and dynamics were incredibly powerful and certainly played with an intensity I have never experienced before. The decay on each note was clearly audible and reverberated through the recorded space. Later in the track the drums and double bass are playing together and on most systems this can merge into one bass line with limited definition. However, with the Stacks everything is present with incredible definition, clarity, attack and texture. The impact and slam of the drums is presented fantastically and the double bass notes (including the plucking of the strings) are presented extremely clearly even though played at a staggering rate. The Stacks portrayed all test tracks with the same intensity, dynamics, subtlety and incredible dynamics. The soundstage was always wide, high, deep and incredibly well layered. Listening to everything in the mix was effortless and one never had to try to follow any vocals or instruments.
(AUVA 100s)
Having read various reviews and having been impressed with the Townshends before I was expecting good things. At least a decent fight… The needle dropped and the first few bars of ‘Take Five’ filled the room… WOW! Nothing more than complete and utter amazement and bewilderment! To my ears (and from the expressions of others present) the Townshends were extremely off the pace of the Stacks. I would expect the difference in speaker isolation to be subtle, but this was a resounding and massive difference. One listener said ‘thousands of pounds has been knocked off the sound quality of your system’! They were right, compared to the Stacks my system sounded like it had taken a big step backwards. Surely this can't be right? I thought the Townshend would be similar… I was expecting different presentations and different strengths and weaknesses, but in my opinion the Stacks were miles ahead! The Townshends sounded veiled and very soft in comparison. The soundstage shrunk completely and the sound was mostly coming from the locality of the speakers with an OK centre image. The layering and depth (presented with the Stacks) had gone with the Townshends - everything was very 2D and flat in comparisons. Surely, there was something wrong? All Townshends appeared fine, if a little used. Given the massive difference I plan to test some new Townshend bars and podiums when possible. I am not expecting them to match the Stacks, however, it is essential to ensure a fair contest. I honestly think the Townshend provide a genuinely large upgrade verses no isolation - they always impressed me on multiple occasions and in multiple systems. However, in my room and system, the Stack takes things to a much higher level. So much so that it is really hard to describe - whatever I write you won’t believe me until you hear it for yourself. Also, perhaps the difference just happens to be extremely pronounced in my system and room. My room has a suspended floor, but it is concrete block and beam in construction, and then comprises PIR insulation and a 70mm concrete screed on top, this is then carpeted (with underlay under). So although suspended, it is a very solid and heavy floor. Perhaps the Stack will be different on a suspended wooden floor? In time we shall know, as various reviewers will be trying the Stacks vs Townshends in their systems. This information will be added to the review thread in due course.
(Townshends - bit blurry, sorry)Back to the Stacks… in addition to the above descriptions, they add a real percussive quality to basslines and instruments. It really is more akin to a real instrument in the room. No, it isn’t completely convincing, is any hifi really completely real? I have certainly never heard drums portrayed like a real drum kit. However, the Stacks certainly take a big step in the right direction. A visceral, dynamic and often surprising presentation – tracks I have listened to for years have been making me jump (really startling) on a system I know incredibly well. Probably the biggest surprise was tracks I know so well just sounded so different. The biggest difference was hearing tracks with a relatively tight and congested mix become open and layered. We’re used to hearing particularly complex passages sound a little congested and it can be hard to hear every thread of the mix, however, the Stacks unravelled these threads in a surprising and spell binding way. I must admit I have been guilty of leaning towards music that is more simple in arrangement and will sound better and be easier to follow. The Stack AUVAs seem to make all my music a thoroughly enjoyable and immersive experience - you feel so drawn into the layers of the soundstage.
Back to the thoughts of everyone else in the room… I will obviously write most from a first person point of view as I can only begin to understand and convey what others were experiencing. However, in time, I expect their views to be added to the thread. There were 4 other people present. For two people the differences seemed massive and they seemed astounded by the differences - this was made clear by looks of amazement and dumbfounded glances across the room. The other 2 people held their cards closer to the chest, however, certainly seemed to really appreciate differences - in addition they were new to my system and music was less known to them. I believe the two people who were less expressive started to realise more merits of each product as the testing progressed.
Next up were the IsoAcoustics GAIA 1s. We had expected these (from reviews) to be a slight step down from the Townshends, however, they were a surprise to us all. Compared to the Townshends, the GAIAs added more vitality and more dynamics to the presentation. In general, they were better resolved and the soundstage became a little higher and deeper again. They weren’t close to the Stacks, but the GAIAs were definitely drawing me a little more into the music (vs Townshends). When compared to the Stacks, the GAIAs had a smaller and less deep soundstage - the music was not as layered and you couldn’t hear effortlessly into the mix. The bass on the GAIAs was less resolved and more bloomy than the Stacks. Rapid plucks of the Double bass (on Bardo - GogoPenguin) blended more into a mass of notes, which were difficult to differentiate. In comparison, the Stacks resolved this rapid succession of plucks with ease. The Stacks were simply presenting the music in an effortless and compelling way.
(GAIA 1s)Whilst music was playing (reasonably loud) I put my hand on the cabinets of the speakers to feel the vibration with the different solutions. Other people tried also. We noted that the cabinets were vibrating very noticeably with the GAIAs and Townshends underneath. However, with the Stacks the cabinets were pretty much vibration free, this difference was shocking. I believe this is fundamental to the large difference in sound quality. Any cabinet vibration will provide a compromised platform for the speaker drivers. The driver membrane is trying to faithfully reproduce the signal, however, any vibrations of the cabinet are producing movements at different frequencies and at different phase angles to the musical signal. In essence this will increase distortion. Smaller details produced by the driver will be smeared and masked by the extra, unwanted vibrations. This isn’t always obvious, but it becomes extremely obvious once the influence of the spurious vibrations are greatly reduced. The drivers become more free to do their job. This is evident across the musical spectrum, everything becomes clearer and better resolved. Compared to the Stacks, the Townshend and GAIAs sounded slower and the space between the notes was reduced - everything merged into one more. With the Stacks, the notes would start and stop much more clearly and any decay was much more resolved.
So far we had done Stack Audio AUVA 100s and then Townshend Seismic bars and then IsoAcoustics GAIA 1s. We were quite surprised by the differences, so felt we needed to return to the Stacks. However, not the 100s this time. How would the much smaller AUVA 70s compare. These are much smaller than the 100s, so will probably not be sufficient for my speakers...
After another (tiring) 10 minute changeover we sat and listened to the AUVA 70s. Normal service had resumed… The Stack sound had returned! All the details, subtlety and composure returned. The soundstage expanded and the speakers disappeared away into the room. The layers returned to the mix and we were frankly surprised what these little (compared to the 100s!) pucks were doing. Perhaps 70s were enough? Were the 100s worth the extra spend? The 70s certainly looked better in our opinion. The 100s aren’t small and although beautifully made they’d don't look as good as the GAIAS or Townshends. The 70s, however, were much more discrete.
(AUVA 70)Another changeover (I was getting tired now!), and the 100s went back in. Within a few seconds the 100s completely justified the price uplift and size increase (IMO). They did everything the 70s did, but they just did is better and added more. They both had the same sound characteristics - very obviously the same tech. The 100s just added more, and they noticeably added more volume (even though the stepped attenuator was in exactly the same place), everything was louder and more dynamic. The 70s weren’t slouches, but the 100s just took it further. The speakers completely disappeared and the soundstage grew larger and deeper.
I think you get the idea now. If it were down to cost and looks I’d choose the Townshends or the GAIAs. Both are readily available cheaper second-hand and are more discrete. I think the GAIAs are definitely the best looking. The stack 100s are pretty large and very hard to find used - now we know why no one is selling them! The Stacks (100s especially) may put a few people off in the looks department, but I doubt many people could hear these in their systems and manage to remove them! I took them out yesterday and lent them to other listeners to try at home. I listened without them and (massive cliché, I know) I really struggled to enjoy it now. I had been finding my system utterly breath-taking and phenomenal for months and now (without the Stacks) it just wasn’t doing it for me. I sure, in time, I reacquaint myself, but the initial come down is a shock.
Will the Stacks have the same effect in all systems? No! It will depend on your speakers and your room, your ears and your perception of relative differences. Also, how much you care about these relative differences. For me, this is a bigger uplift than any of the amp or source upgrades, and much more than changing cables or accessories. Only some of my speaker upgrades have been more profound. This is quite a claim, but it does have to be heard to be believed.
Thanks so much for reading and happy to try and answer any questions. It is so hard to cover everything, so I’m sure I’ll add more in time. There should be many more reviews in other systems/rooms too.
A few details of the items tested:
Townshend Seismic bars - size 2 and load cell D - RRP around £1100
IsoAcoustics GAIA 1s - RRP around £1200 (for 8)
Stack Audio AUVA 70 - RRP £840 for 8
Stack Audio AUVA 100 - RRP £1240 for 8