How the Reverb Impulses are Organized

“Hollywood Impulse Responses” (HIR) was inspired by the ambiences of 20 major Hollywood films released between 1977-2006. The musical scores for these films were recorded in some of the greatest recording studios, sound stages and concert halls in Hollywood and London. The sound of these films was designed to give the listener a “larger than life” listening experience, so often the actual impulses of these rooms are not accurate reproductions of actual acoustic spaces. The source material in these film recordings often contained more bass and lower midrange power than comparable “normal” acoustic spaces, so the perceived size of the reverberant space is often much larger than these studios' physical dimensions would ever be able to create. For an engineer to get this type of sound, a pair of ambient mics would be placed a good distance from the orchestra (usually placed near the ceiling), routed to a digital reverberation unit and then EQ'ed before blending them with the dry signals into the final mix. This approach “samples” the natural acoustics of the room by capturing phase and delay differences between the direct sound and the ambient mics. When all of the dry and wet signals are mixed together, the resultant sound is huge. Capturing and making available to users the immensity and grandeur of the Hollywood film sound is the central focus of this library. Due to this additional signal processing, film ambience is more a composite reverberation impulse (CRI) which is electro-acoustic in nature.

There are two new features in HIR that are new to the word of ambience. First there is the addition of specially filtered RI's designed to adjust the timbre of the overall reverb sound when it is mixed in with the original dry signal. These filters are unique and do not exist in normal analog or digital gear. You have four variations of each RI to choose from: Dark, Warm, Flat, Clear and Bright. The Flat RI's are neutral and do not change the timbre of the source material.

The second new feature is the addition of 6 sets of RI's that are high pass filtered at points of the frequency spectrum that match the exact range of many orchestral instruments. These points are at notes C2, G2, C3, G3, C4 (middle C), and G4. These “instrument designed” RI's add much more sonic precision and clarity to existing sampled instruments and libraries. For example, RI's from the 04_G3 will exactly match the
range of a solo Violin and optimize its tonal character. C3 will optimize Viola timbre and C2 will optimize the timbre of a Cello.

Three numbers are used to describe the "timbral" quality of each RI. These numbers give the user an indication of the relative length of the decay time of the bass, midrange and treble frequency bands. Every RI, regardless of the category, is referenced to the same hall with the average median of (Lo Mid Hi ) 100 100 100. For example, HIR no. 4 has a RI decay characteristic of 129 89 83 which means that the bass frequencies ring or resonate 129% more that the reference hall, 89% (or 11% less) in the midrange band and 83% (or 17% less) in the treble region. So, overall this reverb has a darker sound with more low end resonance. Remember that your source material has to have bass energy in order to hear the RI's effect on low end resonance.

Maximum Ambience For An Audio Sequencer

Once you've completed your arrangement, create several 100% wet tracks using your convolution program (Space Designer, Pristine Space or others), a dry track and the desired HIR to generate the ambience track. Make sure that there is no direct (dry) signal in the wet track. There are 5 different tones for each RI so you could have a Dark, Warm, Flat, Clear & Bright ambient tracks as well as other halls or other HIR pitches all at the same time. In the mixing stage you can use automation to mix the desired ambient track(s) in the final mix changing the levels and thus the tone of each individual instrument in the mix as well as having the tone “evolve” through the course of the mix by changing the levels of selected wet tracks.

All the reverberation impulses are digitally watermarked with a serial number so that each reverb impulse is traceable to the purchaser of this product. HIR ambience can be detected in a final audio mix.

RI File Name	Type of Hall	Location	Bass	Mid-Range	Treble
01_SmSndStg	Small Sound Stage	Toronto	68	78	90
02_SmSndStg	Small Sound Stage	London	77	80	93
03_SmSndStg	Small Sound Stage	London	84	92	102
04_MedSndStg	Medium Sound Stage	Los Angeles	129	89	83
05_MedSndStg	Medium Sound Stage	London	113	90	81
06_MedSndStg	Medium Sound Stage	London	95	102	119
07_MedSndStg	Medium Sound Stage	London	138	96	97
08_MedSndStg	Medium Sound Stage	San Francisco	112	102	127
09_MedSndStg	Medium Sound Stage	London	94	99	101
10_LgSympHall	Large Symphony Hall	Boston	87	120	128
11_LgSympHall	Large Symphony Hall	USA	110	113	116
12_LgSympHall	Large Symphony Hall	USA	114	123	117
13_LgSympHall	Large Symphony Hall	USA	108	130	138
14_LgSympHall	Large Symphony Hall	USA	139	107	125
15_LgSndStg	Large Symphony Hall	London	115	123	120
16_LgSndStg	Large Symphony Hall	Los Angeles	129	132	124
17_LgSndStg	Large Symphony Hall	UK	102	126	118
18_HugeSympHall	Huge Symphony Hall	Boston	183	133	135
19_HugeSndStg	Huge Sound Stage	London	181	156	128
20_HugeSndStg	Huge Sound Stage	London	154	197	200

HIR Pitched Set C4= Middle C

User Guidlines (just suggestions !)

For Set 1 note C2 Full Range Instruments such as Doublke Bass, Cello & Tuba

For Set 2 note G2 Tympani, Trombone

For Set 3 note C3 Viola, Trumpet

For Set 4 note G3 Violin, Alto flute

For Set 5 note C4 Flute, Piccolo, Trumpet & Oboe

For Set 6 note G4 1st Violins, Percussion & Lead Instruments

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