In pursuit of sonic nirvana: the GIK Acoustics experiment continues – with much juggling of bass traps

Back in May I wrote a post about room acoustics. Long story short, the folks at GIK Acoustics had (some months prior) very kindly loaned me a bunch of acoustic panels to use in my Reel-to-Reel Rambler demo room at Hi-Fi Show Live. I was so impressed by them that, before returning them, I took them to my home listening / living room and had a bit of a play. The effect was so dramatic that I immediately realised I could never now live without them. However, the panels I had borrowed were very far from liveable with in my much more compact space, having been designed for a considerably larger one, and so I set out on a quest to find the perfect balance between sonic nirvana and home-friendliness. If you missed the post in May or want a quick reminder to make sense of what’s come, have a quick read of: We need to talk about room acoustics.

Bass traps

So, last time we were talking, I’d just ordered some of GIK’s 244 bass traps and Monster bass traps. A week or so later, they arrived: specifically a pair of 600 x 1200mm 244s and a pair of 600 x 600mm Monsters, all in my preferred ‘Austen’ finish (a natural-looking fabric, kind of sandy in colour).

I chose these particular traps after consultation with GIK’s David Shevyn, who is a mine of useful information and advice. I really enjoy talking with David, as he’s never stingy with his advice, is always open and consultative (rather than talking ‘at’ you as some people do) and one never gets the impression that he’s pushing to make a sale. Besides, his quiet confidence in the products’ performance makes a far stronger impression and instils considerably more confidence than any ‘sales patter’ would.

‘There’s no room in my room!’

Help – it’s a bit crowded in here!

In the meantime, in the interests of being able to actually inhabit my living room, I’d had to dismantle large sections of my sonic nirvana, and was dismayed to return to what now felt like very ‘lumpy’ bass in comparison. Certain frequencies seemed to be cancelling themselves out while others bloomed and swamped the sound – something I’d completely missed ‘before’, until the GIK panels had showed me what ‘after’ could sound like. And above the bass I was now noticing a brash diffuse sound where the midrange and treble energies were being bounced off the room’s boundaries, not only completely messing up the soundstage but also obscuring details and making the sound comparatively quite uncomfortable to my ears. Understandably, I was really excited to get going with my new bass traps.

‘Very different beasts’

Carefully unboxing the traps revealed that these were very different beasts to the GOBO panels (freestanding acoustic panels) that I had been using, as loan stock from the Show. The GOBO panels, while quite large and tall, are just 50mm thick and are made with a wood surround which covered front and back by one’s chosen fabric. The bass traps, however, are only covered on one side and the rear is semi-open. Not to the extent that anything within can fall out, I should add, but what it means is that there’s an air gap built into the carcass so that they can be flush-mounted to a wall or ceiling. This gives a very neat finish while still delivering the optimum sonic performance. Four beefy eyelets are situated within the rear cavity, along with some very meaty picture wire with which to hang them. Sweet!

The first installation: placing the 244s

Okay, now to redo my whole living / listening room, incorporating the bass traps into my set-up. The first step was really quite easy. I’d decided by virtue of previous experimentation that the rear wall, just a few inches behind the couch / listening position, was the prime spot for absorption. I’d tried both absorption and diffraction with the GOBO panels and the few small Diffuser / Absorbers that I already had. I think the main reason that absorption works best in my particular situation (every room is different) is that since the rear wall is so close to the listener (no more than 12”), the diffraction / diffusion approach doesn’t really work.

Anyway, so down came the two GOBOs situated behind the couch and initially I simply balanced the two large 244 bass traps (each 60 cm x 120 cm) on the back of the couch, just to see.  Immediately the improvement was apparent. The bass seemed more even; actually all of the sound seemed more even. The GOBOs had made an audible improvement, but with the two 244s in their place, the improvement was similar but more natural. So I left the traps balanced like this for a day or two until I was quite convinced, and then fixed them permanently with mirror plates for a neat, permanent finish.

Next step: the Monster traps

Now that I had the two 244 bass traps on the rear wall, forming an area some 120cm square, I tried positioning one of the Monster bass traps in the upper corner of the same rear wall, over my right shoulder as it were. This plan was the result of discussions with David Shevyn, who pointed to the top corners as prime spots for treatment.

244s fixed, MBT on trial top right

Wow, the change was immense. But (and there is a but), it wasn’t entirely good. First off, I was really amazed at how much difference just one 60cm square panel could make to my room. The change was as big as any one full element (the two 244s, or the whole gaggle of GOBOs).  The bass became very punchy and clean, but after a short while of listening it became apparent that the timing was somehow confused. The bass, magnificent though it was, seemed to be playing out of time with the rest of the music. So the music didn’t make sense and frankly it was not good at all. So I made a small adjustment to the position of this MBT (Monster bass trap) and  – woah – I heard a clearly different result! Intrigued, I then spent some time making a series of small movements; having installed one large hook, I was able to shift the position of this MBT around by an inch or two at a time. Just one inch of movement sideways made a notable difference, but still, at this point I was struggling to get an overall balanced ‘improvement’ rather than just a ‘change’.

Thanks to my work in hi-fi PR, I’m fortunate to have a lot of ‘visiting’ high-end audio kit coming through my listening / living room, which is a work-space as well as a personal one. So I took the opportunity of trying a number of very different loudspeakers as part of this experiment, switching between Kudos Audio’s Titan 707, the full range studio-bred Kerr Acoustic K100Mk2, and MBL’s omni-directional Radialstrahler 126. While each of the three obviously has its own particular sonic strengths, it was interesting to note that the relative changes in what I was hearing as I adjusting the positioning of my bass traps were fairly consistent across the three models.

So the next thing that occurred to me was, perhaps I ought to try taking out some of the GOBOs and just work with the bass (initially). This really helped. It showed me that with the 244s in place, and even with just the one MBT, I simply didn’t need all those GOBOs (remember I had eight in my phase one set-up!). I had to admit that I’d been overdoing it. Less became more, which was actually a good thing in terms of my ultimate goal: perfect sound with minimum visual intrusion / maximum home-friendliness.

Not so fast…

However, as I continued to play around with further small movements of the top rear corner MBT, the process was becoming slightly frustrating. I couldn’t seem to get a really good balance and quite frankly it was becoming a pain in the butt to keep moving things around high up on the wall (step-ladder fatigue!).  So I thought prior to trying the second MBT in the other rear corner, I’d simply try the first one on the floor instead (in that same rear corner, over my right shoulder, but at floor level rather than ceiling level this time). Well, that was big surprise number two: it didn’t have as great an effect as in the top corner, but the effect was more even and an obvious improvement. Encouraging…

So, while further experimentation continued, that particular MBT stayed in the rear right lower corner. At first I had it straddling the corner at 45 degrees, but ultimately it ended up flat against the rear wall, butted up against the side wall. I’ll fine tune its position before final fixing, as there’s the small matter of needing to be sure I still have ready access to an under-stairs cupboard in that corner of the room!

A change of plan!

This is when the next really big change happened and this was a bit of a road to Damascus.

I had intended that the next area to tackle, phase three as it were, would be the ‘front’ wall of the room. Hanging over and behind my beloved Studer A812 reel-to-reel deck was a bright blue GOBO which formed a valuable part of my initial over-the-top GOBO gathering. However it wasn’t particularly visually pleasing in that spot and it didn’t fit with the room décor. So I figured before going any further with fixing the two MBTs in the rear corners, I’d just try one of them in place of the GOBO, above the Studer.

Woah – slap me sideways with a box of bricks!  This was an undeniably massive change. The MBT did a very similar job to the GOBO – but with knobs on. It had comparable benefits to that particular GOBO, but now those benefits were much stronger and more even. So I grabbed the second MBT from the other rear corner, and placed it on top of the Studer A812’s meter bridge. It was a tight squeeze and to be honest it was never going to be a permanent solution, but it allowed me to hear what increasing the bass trapping in that corner would do. And oh boy, what it did was exceptional.

But I couldn’t leave it like that, I had no intention of balancing large things on top of my precious studio tape deck. I invited a couple of friends, one with a wealth of hi-fi experience and one who’s a studio professional, to come and have a listen. They both agreed: this was, sonically, precisely what was needed. So how could I achieve the same effect without balancing things on top of my Studer?

A bespoke solution

Time for another telephone call to David Shevyn, which went something like this…

“Hello David, the two Monster bass traps I’d intended for the rear corners, well, they’ve found a better home, the front left corner, but they don’t quite fit and are requiring a bit of a balancing act. Tell me, do you do bespoke, custom sizes?”.

David replied yes, of course. Well, that was that, I ordered one more Monster bass trap in the custom size of 60mm x 110mm, just ten centimetres shorter than a standard unit (or the pair of 60 x 60 units I have), which will allows it to hang, rather than having it sit atop my valuable equipment.

Once the new custom MBT arrived, I fixed it to the wall above my Studer deck. Sorted! This then freed up the two original 60 x 60cm MBTs again. For the time being, they’re back in that aforementioned right rear corner, which for some reason sounds better than having one in each rear corner. But I’m holding off permanently fixing these two for now, preferring to wait until I tackle the next stage (clouds – see below) and see what that gives. Flexibility is key here I reckon!

Taking stock so far

Long story short I’ve been very happy with the improvement gained from the 244s and MBTs, not least in terms of value for money: the retail price of the 244s is just £160 (inc VAT) for the pair, and a mere £170 for the pair of MBTs. Which is one heck of a bargain in the world of high-end audio. I have single mains plugs that cost more than all five (including my custom one) bass traps!! So the cost is minimal and the improvement fundamental. Still, you know what us audiophiles are like – always after the next improvement and then the next – and so I couldn’t help but keep fiddling!

And then… time for clouds

I’m on the phone to David Shevyn, who feels that the next step for my particular set-up probably should be clouds. My ceiling is the biggest single expanse in the room (isn’t everyone’s?) and so treating it next makes sense. Whether to use diffusers, bass traps, absorbers etc was far from obvious to me, but David suggested using a couple more 244 bass traps, in the mid-point between the loudspeakers and me, i.e. at the first reflection point. Shoot – that’s exactly where my pendant light hangs. Then again I’ve never liked that light (and have bumped my head on it more than once) so this is the perfect excuse to sort out a different lighting solution for the room! Meanwhile I plan to order four 60 x 60cm 244 bass traps, again in the ‘Austen’ finish. So, once again – I’ll let you know. I suspect this is likely to be the most tricky part of the puzzle yet. Me and that darned step-ladder are about to get better acquainted than ever…

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