I have copied this abstract from the NAMM site, to show the scale of this show and its importance to Sonomax.

About NAMM
The National Association of Music Merchants, commonly called NAMM in reference to the organization's popular NAMM trade shows, is the not-for-profit association that unifies, leads and strengthens the $17 billion global musical instruments and products industry. NAMM's activities and programs are designed to promote music making to people of all ages. NAMM is comprised of more than 9,000 Member companies. For more information about NAMM, interested parties can visit www.namm.org or call 800-767-NAMM (6266).

In addition to this, there is expected 90k visitors and over 1500 booths set up.