conjunction Irith programmed absorption in the auditorium and an automated acoustical shell on the stage. Of a total of thirty projects. all but 1\\0 \I'ere continentally seated (after Bayreuth). The continental seating system and the resulting peripherallobbr that permits fore and aft control of seating capacity therebr aroiding ingress and egress trarerse of the cut-off portion of the auditorium. The lertical configuration of orchestra, grand tier. "Oring" balconr(s) and the concomitant displacement for seating articulated \I'ilh morable ceilings (after the Chicago :\uditorium Theater) set me on course for a thirty year derelopment of contemporary engineering methods for the programming and control of visuall'Olume. seating capacity and reverberation. The 60s and -Os Iritnessed municipallroriented projects \I'hich tended to incorporate larger-sized auditoria areraging 2.300 in the maximum seating mode. Seating geometries utilizing one or more balconies racillated betlreen mutations of the fan and the shoebo\. The 80s and 90s hare seen mostlY educational institution projects demonstrating a marked tendency to\l'ard smaller-sized auditoria areraging 1.300 in the m;L\imum seating mode. Oyerall. seating geometries. sans balconies. Irhen combined \rith the efficiency of cominental seating, favor the shoebo\ and structural simplicity of Boston Srmphony Hall. This. more than anI' other factor, was responsible for the rescue of eight medium and smaller-sized recent projects which Irere raraged by budget constraints. These, as a group, can best be defined as a series of ongoing schemes for an ere I' more progressive "fooling of the ere but not the ear" that became erer more sensitive to ever more tightening budget situations. D Y:'\A:-'IIC E:'\GI:'\EERI:'\G ..\.:'\0 ACOUSTICAL OESIG:,\ From the rery beginning of mr consulting practice. it Iras of crucial importance to determine an economiGlI solution to the acoustical problem of determining minim;lI critiGlI mass and surface hardness of the facing materi;t1s essential to the design of acoustical substructures (Iralls and ceilings) in the auditorium and the acoustical shell on the stage. To this end. I Iras the instigator of two separatc acoustical cngineering studies Irhich Irere carried out independentlr br Bolt Beranek and 'ielrman prior to the design of Jones /-Iall in 1963 and br \'ern O. Knudsen at LCL-\ prior to the design of Thomas Hall in 1968. The studies I'ielded identical results. TIro pounds per square foot Iras determined to be the critical mass and the surface hardness of pl\\rood: g:vsum board and dampened mild carbon steel of this unit mass Irere approred equals. For reasons of structural design flexibilitl. for the obrious economies gained by not mi~ng bUilding trades plus the adrantages accrued from off-site fabrication and ease of on-site erection. I chose mild carbon steel. Despite sly innuendoes lereled at me br certain members of the acoustics and theater consulting fraternities. I continue to Slick to mr guns. In over thirty rears. I hare not designed other than ;1Il automated dampenedsteel acoustical shell. There is an amusing aside concerning use of dampened-steel and acoustical perception that over time has acquired the staws of an apocryphal "in joke" among mrself ;Uld mr associates. Some rears ago. a multiple-use concert h;lil-theater Iras dedicated Irith a pel' formance by one of the major metropolitan svmphoIl\' orchestras, conducted by a renOlmed Irorld-class musician. Glancing around the auditorium prior to the rehearsal. the conductor noticed \I'hat appeared to him as wood paneling bm \\'hich was acwallr dampened sheet steel covered over Irith a Irood-grained vinyl Irall covering material. A treatment which ever since has been referred to "tongue-in-cheek" as aconslical u·allpaper. At the conclusion of the rehearsal. the conductor MtS glowing in his praise of the acoustics. !llost particularlr. he I\'aS pleased to reassert the "old Sail''' that Irood Iras the ideal material Irith Irhich to line a concert hall. "Ho hum", said I, so//o !'Oce. Some rears later. this time in a hall Irith nothing more than a coat of paint on an identical dampened-steel paneling srstem. the music critic of one of the large metropolitan nelrspapers commented on the bass response of this "steel-lined" hall: "The opening had a lI'onde/jnl sense ofgmndelll: lI'ilh ils groll'ling bmss and Ihe u'onde/jnl nse of Ibe bass dl'lllll 10 nnderscore Ihe r/mllia. In Ihe balcon)'. )'on could acluall)' feel Ihe l'ibmlions frOIli Ihe softl)' p/r~)'ed dl'lllll. A I'e/T illipressil'e acouslical accolliplishlllen I. " De~ign 1I.IIfiilii BUIld II. Install II. 10&1 F ..\ I T~~~:~~~ce That Makes ADifference.