IsoThermal TubeTrap™

Acoustic Bass Traps


Just like the classic TubeTrap you know and love, the new IsoThermal TubeTrap is a self contained broadband acoustic absorber/diffuser. Both models work by utilizing a reactive acoustic circuit that is powered by the sound pressure in your room. Both models work best where the sound pressure is the strongest, which is in the corners and against the walls in your room.

are an improved TubeTrap that provides double absorbing power in the sub-bass range, below 60Hz and enhanced bass absorption up through middle C, or 260Hz. That’s why the IsoThermal TubeTrap has two chrome dots along the rim instead of the traditional one dot: two dots means twice the power!

By eliminating the thermal component of acoustic pressure, The IsoThermal TubeTrap has an effectively 40% larger internal volume below 150 Hz, which doubles its absorbing power while retaining all of the other familiar sonic characteristics of the TubeTrap you know and love.

Finally: You can get rid of the dreaded "rear wall bounce frequency suckout." (and also increase your bass absorption below 250 Hz!)


Because of the dynamic performance of the IsoThermal TubeTrap, it is at home in a variety of venues giving you extended low end absorption and increased efficiency. 

  • Home Theater
  • High End Listening Rooms
  • Recording Studios


The IsoThermal TubeTrap offers:

  • Extended bass absorption below 250 Hz
  • Treble diffusion (or absorption) above 250 Hz
  • Great for controlling the phase add/cancel effects of the rear wall bounce
  • Available in a variety of sizes, each with their own absorptive properties
  • 30 day, 100% satisfaction guarantee
  • Sturdy hand crafted construction

File Downloads

Recommended TubeTrap Room Setups:

How It Works

We developed the IsoThermal TubeTrap to aggressively manage typical HiFi rear wall bounce phase-cancel effects.  What we got was a major performance boost across the entire bass spectrum.  And we did it without altering the fundamental voice of a TubeTrap.

Check out the absorption data for the new 16" Isothermal TubeTrap compared to a standard 16" TubeTrap.  Power is doubled in the sub-bass range, while the LF rolloff is extended by over half an octave!  The efficiency of the unit is a solid 40% greater all the way up through the "muddy" range of bass. 

We were even more impressed when third party theoretical calculations made in ESI's NOVA software (a multi layered acoustic simulator used in advanced acoustic engineering) corroborated our data to an uncanny degree.

As with standard TubeTraps, larger diameter units reach to lower frequencies.  However, with the IsoThermal upgrade, the operating frequency of each size TubeTrap has come to match that of the next model size larger, approximately.  This means that if you previously used and loved the sonics of a 16" TubeTrap, you can now replace your old tubes with new 13" IsoThermal TubeTraps, with very similar voicing.  Better yet, if you always wished you had the space in your room and money in your wallet to fill your corners with deep-breathing 20" TubeTraps, now you can simply upgrade your system with 16" IsoThermal TubeTraps to manage that 35 Hz rumble.

What is the IsoThermal effect?  The short story begins with the statement that when you compress gas, it heats up, while when it expands, it cools down.  High pressure sounds entering the acoustic capacitor of a TubeTrap cause a rise in pressure, or compression.  When the air pressure inside the TubeTrap reaches that of the ambient air outside it, the capacitor is essentially "full."  The air then cools off fairly rapidly due to thermal and hydraulic losses, and returns to low pressure, ready to be filled up again.

The frequency of this "filling-up" is proportional to - you guessed it - the frequency of the sound.  Therefore low frequency sounds "fill up" the capacitor much more quickly, due to the slowness with which they propagate through the media.  A larger capacitor (think of a 24" TubeTrap) takes the longest to fill, and so reaches the lowest frequencies.

The conversion of the capacitive section of a TubeTrap into an isothermal vessel alters this behavior in a very beneficial way.  The low-pressure air inside the capacitor is prevented from rising in temperature upon being subjected to a high-pressure pulse.   Through this action, the effective size of the capacitor is increased by 40%, almost as though the IsoThermal TubeTrap is 40% larger than it appears!  (This comparison is not quite accurate, since other factors come into play regarding the resistance of the absorptive material among various TubeTrap models, but it is a good approximation).


While the IsoThermal TubeTrap is very similar to our Standard TubeTrap, its extended low frequency absorption makes it perfect for treating the rear wall of your room. In any listening environment, the rear wall bounce creates the most bothersome of LF low frequency problems: the phase-cancel effect, also known in HiFi as a “suck-out”. If someone has an 8 dB suck-out at 49 Hz, they usually get tired of hearing the same note drop out of double bass riffs. 


Imagine listening to your HiFi outside. Your speaker has a flat frequency response and the sound waves are flying right past you at the speed of sound.


Now imagine someone drops a wall a few feet behind you. Now, the sound that used to fly right past you and out of your life forever bounces off the wall and flies past you again a few milliseconds later.


Basically, it’s easy to control the rear wall bounce. Just get rid of it. Open the window or door behind you and let the bass wave keep on going.


Related Products

Check out the other member of our bass trap family!



Absorption Curve





The IsoThermal TubeTrap

Model Height     MSRP*
11 inch 3' (nominal)     $1074/box of 2
13 inch 3' (nominal)     $1136/box of 2
16 inch 3' (nominal)     $698 ea
        *USA Only