Hello, I am a new member to this forum, and am getting into home audio. I am familiar with many of the ideas and concepts behind DIY audio since I have been into mobile audio for a few years. Now, on to the question. I have an Adire Audio Tempest and an Adire Audio AVA250 amplifier on order, and am planning on building an enclosure out of a sonotube. I called around to all the local cement and construction places and none of them sell sonotube. My local hardware stores don't carry it either. Where did you all purchase your sonotube, and do you have any idea where I could purchase some? I was aiming for an 18" sonotube (but I can be flexible), and I need just under three feet of it. Thanks in advance for the replies.