functions.php

<?php

//  register the custom post type widget area
genesis_register_sidebar( array(
        'id'            => 'cpt-archive-sidebar',
        'name'          =>  __( 'Custom Post Type Sidebar' ),
        'description'   =>  __( 'Display this sidebar on your custom post type archive page.' ),
) );


add_action( 'genesis_before_sidebar_widget_area', 'cpt_genesis_before_sidebar_widget_area' );
/**
 * Callback for Genesis 'genesis_before_sidebar_widget_area' action.
 * 
 * If on custom post type archive page, remove default sidebar (widget area).
 * 
 * @author Ryan Meier http://www.rfmeier.net/
 * @package Genesis
 * @category Widget Area
 */
function cpt_genesis_before_sidebar_widget_area(){

	//	if not on custom post type archive page, return
	if( is_post_type_archive( 'custom_post_type' ) ){

		//	remove default widget areas if on post type archive pages
		remove_action( 'genesis_sidebar', 'genesis_do_sidebar' );

	}

}


add_action( 'genesis_sidebar', 'cpt_genesis_sidebar' );
/**
 * Callback for Genesis 'genesis_sidebar' action.
 * 
 * If on custom post type archive page, display cpt widget area
 * 
 * @author Ryan Meier http://www.rfmeier.net/
 * @package Genesis
 * @category Widget Area
 */
function cpt_genesis_sidebar(){

	//	if not on custom post type archive page, return
	if( ! is_post_type_archive( 'custom_post_type' ) )
		return;

	// display the post type archive widget area
  	genesis_widget_area( 'cpt-archive-sidebar' );

}