To obtain good speech and music reproduction from a superheterodyne radio receiver a wide level IF pass band is required.  Selectivity is also necessary.  These two requirements are conflicting.
In popular priced receivers it is usual practice to keep the IF transformer coupling factors less than critical (Q<=1).  This has the advantage that IF alignment is simply a peaking procedure carried out at one frequency, but the higher audio frequencies are lost (Fig. 2c).  Attempts are often made to "restore" them in the AF stage which may be one reason why it is usual to fit a "tone control."
Briefly the trouble is the Miller effect in the IF amplifier valve (positive feedback through Cg1-a) which produces asymmetrical peaks (Fig. 2a) in the response of an overcoupled IF transformer in the grid circuit.  Most of the difficulties of alignment are associated with compensating for the asymmetry by staggering the circuits to slightly differing frequencies.
Our engineers have overcome the problem by a simple circuit in which Cg1-a is neutralized (Cn in fig.1).  The unwanted feedback is eliminated, thus allowing a symmetrical response to be obtained easily.  By this means we have been able to gain the advantage of the tone quality associated with wide band response without sacrificing either selectivity or simplicity of alignment in modestly priced receivers.
This new circuit is incorporated in the new Ultra "Leader 51" and Ultragram.  You will no doubt be interested in listening to them.