A submerged combustion melter comprising at least one submerged combustion burner , said combustion burner comprising: an inner conduit having inlet and exit ends; and an outer conduit having inlet and outlet ends substantially juxtaposed to the inlet and exit ends of the inner conduit , with the proviso that the outer conduit exit end extends beyond the exit end of the inner conduit by a length sufficient to create a fuel and oxidant mixing region downstream of the inner conduit exit end, the outer conduit substantially concentric with the inner conduit; wherein B) the inner conduit comprises one or more through-holes positioned within about three inner conduit diameters from the exit end of the inner conduit configured to provide intermixing of at least some fuel and oxidant within the inner conduit and the inner conduit exit end has a diameter slightly smaller than a diameter of the balance of the inner conduit or C) the burner comprises at least one partial obstruction , in the mixing region sufficient to increase mixing between the fuel and the oxidant in the mixing region upstream of a point of combustion of the fuel and oxidant, wherein the increase is relative to a similar burner without such partial obstruction, the partial obstruction , comprises one or more baffles extending from an inner surface of the outer conduit, an inner conduit having inlet and exit ends; and an outer conduit having inlet and outlet ends substantially juxtaposed to the inlet and exit ends of the inner conduit , with the proviso that the outer conduit exit end extends beyond the exit end of the inner conduit by a length sufficient to create a fuel and oxidant mixing region downstream of the inner conduit exit end, the outer conduit substantially concentric with the inner conduit; wherein B) the inner conduit comprises one or more through-holes positioned within about three inner conduit diameters from the exit end of the inner conduit configured to provide intermixing of at least some fuel and oxidant within the inner conduit and the inner conduit exit end has a diameter slightly smaller than a diameter of the balance of the inner conduit or C) the burner comprises at least one partial obstruction , in the mixing region sufficient to increase mixing between the fuel and the oxidant in the mixing region upstream of a point of combustion of the fuel and oxidant, wherein the increase is relative to a similar burner without such partial obstruction, the partial obstruction , comprises one or more baffles extending from an inner surface of the outer conduit, B) the inner conduit comprises one or more through-holes positioned within about three inner conduit diameters from the exit end of the inner conduit configured to provide intermixing of at least some fuel and oxidant within the inner conduit and the inner conduit exit end has a diameter slightly smaller than a diameter of the balance of the inner conduit or C) the burner comprises at least one partial obstruction , in the mixing region sufficient to increase mixing between the fuel and the oxidant in the mixing region upstream of a point of combustion of the fuel and oxidant, wherein the increase is relative to a similar burner without such partial obstruction, the partial obstruction , comprises one or more baffles extending from an inner surface of the outer conduit, <EOS>