ACS acoustic cleaning system horn. It's a modified Model AC 943 with the AC-910 bell section C (no flange at the end, also slighty longer section) 117.5lbs. It is 7 feet 9 inches tall ( 4" taller than my "NASA" horn). Working pressure is only 80psi, with an air consumption of 80 SCFM, and it is suppose to produce a clean 75Hz sound @150dB (may produce slighty lower than 75Hz due to the longer bell section c). This is the largest and the lowest given Hz of any Acoustic cleaning horn.

More about what this horn is used for:

Acoustic cleaners are applied in a wide range of applications, therefore they are offered in various frequencies and sizes. The lower the fundamental frequency the greater the cleaning area as well as the physical size of the unit.
The function of an acoustic cleaner is simple, compressed air is introduced through a specific orifice and causes the titanium diaphragm to flex. The flexing causes a pressure pulse to be produced that is then amplified by the bell. The length and flare constant of the bell is what determines the fundamental frequency.
The sound pressure produced by the bell causes particulate deposits to resonate and dislodge. Once dislodged, the material is removed by gravity and/or gas flow.
Acoustic cleaning is a non intrusive technology designed to remove particulate buildup wherever ash, dust, powders or any other dry materials cause buildup, blockage, or thermal transfer problems.

My vehicle has 4 air compressors. 2 Viair 480's, 2 Oasis XD3000 heavy duty air compressors. The compressors fill the tank to 200psi and pumps turn on when pressure in tanks go below 80psi. it then passes through a pressure regulator to adjust for the different horns I demo. I have 3 air tanks linked together for a total of 52 gallons of available air. The compressors are switched off when recording the horns to prevent any unwanted sound . (less info)