IsoAcoustics: ISO-Puck

This January I was wandering around the NAMM Show, looking at all the fancy new recording gear on display in the new Anaheim Convention Center North Hall, when I ran into producer/engineer Darrell Thorp. Being the enthusiastic guy that he is, he dragged me along to the IsoAcoustics booth where we listened to a quick demo of their ISO-Puck acoustic decoupler. They had two pairs of decent mid-sized studio monitors sitting next to each other, and one pair was simply placed on the support surface, and the other pair had some 2.4-inch diameter ISO-Pucks raising the speakers slightly off the surface for acoustic decoupling. Quickly A/B'ing between the two we could hear more focus and clarity in the pair on the ISO-Pucks. I figured if I could hear this difference on a noisy trade show floor, I'd better give these a listen in my studio. A while later, four two-packs of the ISO-Pucks showed up for review. These pucks are mostly intended to use with studio (or home) monitors, but apparently can be used under bass or guitar amplifiers and turntables, though we didn't experiment with these uses.

For many years, Jackpot! has been using a certain brand of foam and metal speaker decouplers under our main ATC SCM25A monitors [Tape Op #101]. Testing at the time proved to me that these decouplers were incredibly better than no decoupling, and also a step up from some "all foam" ones I'd previously been using.

My studio manger and house engineer, Gus Berry, joined me post-session one night to help me review the ISO-Pucks. After measuring for the proper equilateral triangle listening spot, we marked the floor with blue masking tape to keep our listening chair in the proper place (check our Instagram for a photo). We also measured the monitors' distances from the walls so we could match their placement in the room when we changed out decouplers. We picked two classic rock songs and listened intently at 85 dB; swapping out being in the chair a few times. Then we set up a pair of Earthworks TC30 mics (through Grace 501 preamps and BURL B80 Mothership D/A [Tape Op #84] to record both songs from the listening position. First we tracked the songs via our existing setup, then we swapped out the decouplers for the ISO-Pucks and tracked the songs again (while sitting in the lobby waiting). Afterwards, we came in and listened to the actual songs again over the monitors, now with the four ISO-Pucks installed under each one. Then we listened to the two different recordings of both songs, repeating certain parts and A/B'ing over and over. Later I took the files home to listen to closely over quality headphones [Focal Spirit, Tape Op #98] for further analysis.

Gus and I initially had opposite perspectives on the differences we heard. Gus felt the low end was weaker with the ISO-Pucks, and I believe this set off alarms for him that something was wrong. As soon as I stepped up to the listening position, I heard an increased clarity in the detail of the low end with the ISO-Pucks, even though there was less low end overall. Astute readers will know what we heard; the previous decouplers were not doing the best job. They were reinforcing various frequencies of the low end, and it's possible that in interacting with the metal plate of the decoupler that some other low resonance was added to the room. The ISO-Pucks, on the other hand, seemed to be solving more of the decoupling issue, even if there was now slightly less low end in the control room. Looking at the recordings of the room in iZotope RX6 [Tape Op #123] in spectral view, we could see that the audio was not the same between the two decouplers. The lows, below 50 Hz, had a lot of random energy all through the tracks, whereas the monitors on ISO-Pucks were visibly clearer in the bottom end. We could see that deep low bass lines had less low end "noise" around them, and this confirmed our listening tests – sure, it had felt like "more" low end was in the room, but there had been less clarity. High end was different as well.

Examining high frequency transients, we could hear a slight edge on clarity with the ISO-Pucks. This was confirmed with cymbals, chimes, and other sounds in this range. But one thing blew us both away, and it was similar to what I had heard on the noisy NAMM Show floor: The phantom center was far more focused. Not only when we listened to tracks and some of our current sessions in the room for real, but when we listened back to the room recordings and A/B'd them, we heard a clearer center image and were impressed. Another unexpected change occurred. The midrange focus of our venerable Yamaha NS-10m pair had never really made sense when switching between them and the ATC SCM25As. Now we both noticed that the midrange focus of the ATCs was much clearer, and strangely more similar, to the NS-10m pair. Something new was happening in Jackpot! This simple act of changing out the decoupling had improved our control room listening.

Decoupling is real. Don't ever set up your studio or listening area and think you can avoid dealing with this. Whatever your monitor is sitting on, inside of, or suspended by will change its sound. When you've dropped $8,500 on a pair of monitors like the ATC SCM25A, $240 on some ISO-Pucks to improve the decoupling, and improve the sound, is well worth it.