User manual MARTIN AUDIO WAVEFRONT COMPACT APPLICATIONS GUIDE

[. . . ] CONTENTS < > ENGLISH ONLY GUIDES PRINT Wavefront Compact Series Applications Guide MARTIN AUDIO LONDON The Martin Experience All material © 2007. Subject to change without notice. CONTENTS < > ENGLISH ONLY GUIDES PRINT Wavefront Compact Series Applications Guide Contents Introduction Section 1 Section 2 Section 3 Section 4 Section 5 Wavefront Compact Series Overview W8C 3-way System W8CT & W8CM Line Array System W8CS Flown Subwoofer WSX Folded Horn Subwoofer W8L Series Line Array Systems Appendix A1 A2 W8 3-way System W8S HybridTM Subwoofer MARTIN AUDIO - APPLICATIONS GUIDE, WAVEFRONT COMPACT SERIES All material © 2007. Subject to change without notice. CONTENTS < > ENGLISH ONLY GUIDES PRINT Introduction Wavefront Compact Series Overview Thank you for purchasing a Martin Audio Wavefront Compact Series system. Wavefront Compact Series products make up a coherent "toolkit" of compact, live sound enclosures covering a huge range of professional sound projects from high quality club installations to major touring and festival systems. Unpacking Each Martin Audio loudspeaker is built to the highest standard and thoroughly inspected before it leaves the factory. [. . . ] 1) 2) 3) 4) 5) Set the front & rear WSX arrays to match the main front & rear corner system farfield levels around 120Hz Set the front & rear W8Cs to balance the main systems + WSXs in the nearfield Set the flown centre W8Cs to balance the main systems + WSXs + W8Cs in the L, R & centre/mix position midfield areas Set the apron W3s to fill the L, R & centre nearfield region Set the apron WSXs to match the W3s around 120Hz Island stages (not shown) Island stages are simply four-sided versions of examples 3 and 5 and should be aligned using the same process. MARTIN AUDIO - APPLICATIONS GUIDE, WAVEFRONT COMPACT SERIES All material © 2007. Subject to change without notice. CONTENTS < > ENGLISH ONLY GUIDES PRINT 4. 10 Spaced systems Whenever two or more loudspeaker systems are fed with the same signal and their coverage overlaps, sound addition and subtraction will take place depending on the listener's position. In the following example, the off-axis listener may hear delayed sound from the right hand system. The two loudspeakers are driven in phase (both were +ve just before the instant shown) but the extra distance travelled by the second (R) signal causes it to be out of phase at the listener position at that particular frequency (R is -ve while L is +ve). Reflections Remember that a strong side wall reflection will act like a second source and the direct and reflected signal will combine as if they were two sources. The direct signal will combine with the reflected signal as if it were a phantom source in the position shown. MARTIN AUDIO - APPLICATIONS GUIDE, WAVEFRONT COMPACT SERIES All material © 2007. Subject to change without notice. CONTENTS < > ENGLISH ONLY GUIDES PRINT Addition & Subtraction The above shows how two pairs of sine waves (with identical amplitude and frequency characteristics) will sum. Pair (b) are out of phase and cancel. MARTIN AUDIO - APPLICATIONS GUIDE, WAVEFRONT COMPACT SERIES All material © 2007. Subject to change without notice. CONTENTS < > ENGLISH ONLY GUIDES PRINT Polar variations with frequency Whether particular frequency components add or subtract in the far field will depend on the loudspeaker system spacing, the angular offset of the listener with respect to the centre line, and the wavelength. The following polar responses show what happens when subwoofers are placed 8. 6m apart and are driven in unison at various frequencies: 100Hz The polar plot shows the far field polar response of the two subwoofers when driven in phase with the same 100Hz signal. Subwoofer interaction causes irregular coverage either side of the centre line. Response nulls (cancellations) occur at the sides because the spacing is an odd number of half-wavelengths causing this frequency component to cancel in the far field. 80Hz The above shows the same system at 80Hz. At this frequency the central position remains well covered but the polar pattern has MARTIN AUDIO - APPLICATIONS GUIDE, WAVEFRONT COMPACT SERIES All material © 2007. Subject to change without notice. CONTENTS < > ENGLISH ONLY GUIDES PRINT changed dramatically around the sides. There are now strong lobes at the sides because the spacing is now an even number of half-wavelengths at this particular frequency. These lobes could cause low frequency feedback problems on stage with the high microphone gains used for orchestral low string (cello, double bass) sections or for "unplugged" performances. 60Hz At 60Hz the spacing is an odd number of half-wavelengths again so we see side nulls again. 40Hz When the frequency drops to 40Hz, the 8. 6m spacing = 1 wavelength. Again, the central response is maintained but there is a dip in response over wide areas either side of the centre. The spacing is an even number of half-wavelengths again so we see side lobes again. MARTIN AUDIO - APPLICATIONS GUIDE, WAVEFRONT COMPACT SERIES All material © 2007. Subject to change without notice. CONTENTS < > ENGLISH ONLY GUIDES PRINT 40 Hz reduced spacing The above shows what happens at 40Hz if we reduce the spacing between the subwoofers to 4. 3m. We get better central coverage without 40Hz side lobes - adequate for long, narrow "shoe-box" venues but wider coverage would be required for most arenas. 40Hz close coupled Close coupling would give a wider coverage at that frequency but the spacing could still give coverage irregularities at mid-bass frequencies due to the shorter wavelengths at higher frequencies. The real world Bass notes usually include harmonic components each with a different wavelength. Some will add giving an amplitude peak whilst others will subtract giving an amplitude dip. This will give tonal changes with listening position and emphasise particular notes and timbres. MARTIN AUDIO - APPLICATIONS GUIDE, WAVEFRONT COMPACT SERIES All material © 2007. Subject to change without notice. CONTENTS < > ENGLISH ONLY GUIDES PRINT In the following example, listeners over a wide central area will hear a warm bass note rich in harmonics whereas those around the sides (in line with the subwoofers at 90º) will hear less of the fundamental but more of the harmonics whose full wavelengths coincide with the subwoofer spacing. Listeners in the 60º zone will hear the note at a reduced level and may be more aware of room reverberation because the direct-to-reverberation ratio would be poorer for that note. [. . . ] (Important: see safety note above) Use short stacks for short, wide vertical shots. This will cause a vertical stack to perform as if it were double the length, giving a useful low frequency boost accompanied by a narrower, more complex polar response. MARTIN AUDIO - APPLICATIONS GUIDE, WAVEFRONT COMPACT SERIES All material © 2007. Subject to change without notice. CONTENTS < > ENGLISH ONLY GUIDES PRINT For instance, a 4 high ground-stack of W8S' will act like the top half of an 8 high stack. (Important: see safety note above) Note that flexible floors may actually absorb sound at some frequencies so the situation isn't always so simple in practice. [. . . ]