towards open 3d multichannel sound diffusion systemsnando/publications/diffusion... · 2013. 11....

(C) Fernando Lopez-Lezcano 2013EMW 2013

Towards open 3D multichannel sound diffusion systems

Fernando López LezcanoCenter for Computer Research in Music and Acoustics

(CCRMA), Stanford University

(C) Fernando Lopez-Lezcano 2013EMW 2013

diffusion systems

● what I won't talk about:– how to compose for 2D/3D large scale systems

(techniques, tools)

– challenges faced when the venue size grows

– how to curate and “compose” a concert

– details about the various subsystems

(C) Fernando Lopez-Lezcano 2013EMW 2013

diffusion systems

● two main types:– “transparent” systems, they try to create or recreate

a sound field

– loudspeaker orchestras, the speakers are the “instruments”

(C) Fernando Lopez-Lezcano 2013EMW 2013

diffusion systems

● two main types:– “transparent” systems, they try to create or recreate

a sound field

– loudspeaker orchestras, the speakers are the “instruments”

● Acousmonium

(C) Fernando Lopez-Lezcano 2013EMW 2013

diffusion systems

● two main types:– “transparent” systems, they try to create or recreate

a sound field

– loudspeaker orchestras, the speakers are the “instruments”

● Acousmonium● BEAST

(C) Fernando Lopez-Lezcano 2013EMW 2013

diffusion systems

● commercial systems– loudspeakers + digital mixer

– packaged solutions

● custom systems– software created for one or many concerts

– general purpose software (a package)

● permanent systems (part of a concert hall)

(C) Fernando Lopez-Lezcano 2013EMW 2013

diffusion systems

the emergence of open source and free (as in “freedom”) software and open computer systems that span from the operating system itself to the user programs allow the creation of highly complex and configurable diffusion systems

– GNU/Linux: pick your distribution (Fedora + Planet CCRMA, Ubuntu Studio, ArchLinux, Gentoo, etc)

– PCs: beyond Windows

– try to use and reuse existing software: Jack & friends

(C) Fernando Lopez-Lezcano 2013EMW 2013

hardware: computer

● general purpose PC... but:– high speed (4 to 6 cores, 32 to 64G RAM)

– raid array for storing audio/video

– low noise or no noise (depends on the environment in which it runs)

– A/D D/A converters● high quality, expensive: RME pci/pci-express family● USB2● “exotic” options - digital snakes and jack-mamba

(C) Fernando Lopez-Lezcano 2013EMW 2013

hardware: computer

(C) Fernando Lopez-Lezcano 2013EMW 2013

hardware: speakers

● passive● active (our choice)

– all in one design, good if properly tuned

– no separate amps, no heavy wiring

but:– need to route power to all speakers

(C) Fernando Lopez-Lezcano 2013EMW 2013

hardware: speakers

● we wanted:– flat frequency response

– best if up to 20KHz

– wide dispersion angle

– no fans

– reasonable cost

– rugged

(we are using the QSC HPR122i mains / HPR181 subs, very good but no longer manufactured... how we bought them is a long story in itself)

(C) Fernando Lopez-Lezcano 2013EMW 2013

software

● GPL & other licenses: free(dom) software– jack

– ambdec, ADT

– jconvolver, DRC

– zita-lrx (linkwitz-riley, 4th order)

– supercollider / supernova / custom ugens (LR4)

– ardour 2 / 3● ... and many others (meterbridge, jaaa, japa)...

(C) Fernando Lopez-Lezcano 2013EMW 2013

software

● GPL & other licenses: free(dom) software– the linux kernel... latest one patched with the RT

(realtime) low latency patch (3.8.10-rt11)● realtime scheduling for sound processes● we can use very small sound buffers (64 x 2)● interrupt request priorization (through rtirq)

– end result: no sound glitches even when the workstation is fully loaded

(C) Fernando Lopez-Lezcano 2013EMW 2013

examples

● control system of the Listening Room● “large scale” diffusion system

(C) Fernando Lopez-Lezcano 2013EMW 2013

listening room

● built in 2004/2005● nearly anechoic● noise floor below 24dB● 7.036x7.417x 2.184● acoustically transparent floor

(C) Fernando Lopez-Lezcano 2013EMW 2013

listening room

(C) Fernando Lopez-Lezcano 2013EMW 2013

listening room

(C) Fernando Lopez-Lezcano 2013EMW 2013

listening room

configuration:

1 + 6 + 8 + 6 + 1

(really 23, we have a “center” speaker)

22 speakers 8 x HR824 + 14 x HR6244 subwoofers SBX-10

(C) Fernando Lopez-Lezcano 2013EMW 2013

listening room

● hardware● software

(C) Fernando Lopez-Lezcano 2013EMW 2013

listening room: hardware

sound sources

diffusion system

controls

(C) Fernando Lopez-Lezcano 2013EMW 2013

listening room: software

● OpenMixer (written in supercollider)● jack● aj-snapshot● jacktrip● netjack (netone)● jconvolver● ambdec_cli● (open sound control)

(C) Fernando Lopez-Lezcano 2013EMW 2013

listening room: interface

(C) Fernando Lopez-Lezcano 2013EMW 2013

listening room: interface

● 44.1/48KHz – normal and ambisonics modes● inputs:

– 24 channel digital i/o from workstation

– 16 analog balanced inputs

– 16 channel ADAT interface (2 i/o ports)

– 8 microphone inputs

– 7.1 channels from blu-ray player

– up to four 24 channel ethernet interfaces (netjack)

● outputs:– 23 main speakers, 4 subwoofers

(C) Fernando Lopez-Lezcano 2013EMW 2013

multichannel diffusion system

● goals:– transparent, high quality sound

– flexible and adaptable

– medium/high speaker count

– not expensive

(C) Fernando Lopez-Lezcano 2013EMW 2013

multichannel diffusion system

● hardware– PC (6 core / 64G ram)

● remoted display and interfaces (optional, ethernet)

– NetworkSound Digital Snake (1/2)● analog input and output (32/32), ethernet driven

– RME RayDAT● digital input and output (4 x ADAT, optional)

– BCF2000● mixer control

(C) Fernando Lopez-Lezcano 2013EMW 2013

multichannel diffusion system

● software (current)– supercollider

● volume and delay compensation, LR4 crossover● volume and delay “bias”

– ambdec and/or ADT (Ambisonics Decoder Toolkit)● ambisonics decoder (up to 3rd order periphonic)

– jconvolver● DRC (Digital Room Correction)

– ardour2/3● live “mixer” or soundfile playback system

– jack-mamba (drives the ethernet a/d d/a converters)

(C) Fernando Lopez-Lezcano 2013EMW 2013

multichannel diffusion system

● each concert is a new experience● the software is developed / tweaked for

each concert / venue / speaker setup

(C) Fernando Lopez-Lezcano 2013EMW 2013

concerts

● 2010: CCRMA Backyard 8 x HPR212i .2

● 2011: Transitions: 8 + 8 .4

● 2012: Transitions: 24.6

● 2013: Bing! (and beyond)● Opening Night Fanfare (10 + 5 PA + .4)● Bada Boom Bada Bing Festival (2 nights, 24.6)● From Constantinople to California (Hagia Sophia, 24.6)● Jonathan Berger's chamber operas (24.6, ambisonics, ADT)

● 2013: Outsound Music Festival (one night, 8.2)

● 2013: Transitions: 20.6, ADT, DRC

(C) Fernando Lopez-Lezcano 2013EMW 2013

concerts

● Transitions 2012

(C) Fernando Lopez-Lezcano 2013EMW 2013

concerts

● 2012: Transitions (24.6)

(C) Fernando Lopez-Lezcano 2013EMW 2013

concerts

● Transitions 2012

(C) Fernando Lopez-Lezcano 2013EMW 2013

concerts

● Transitions 2012

(C) Fernando Lopez-Lezcano 2013EMW 2013

concerts

● “From Constantinople to California”

(C) Fernando Lopez-Lezcano 2013EMW 2013

concerts

how to fit this...

into this:

(C) Fernando Lopez-Lezcano 2013EMW 2013

concerts

how to expand this...

into this:

(C) Fernando Lopez-Lezcano 2013EMW 2013

concerts

● “From Constantinople to California”

(C) Fernando Lopez-Lezcano 2013EMW 2013

concerts

● From Constantinople to California

– signal routing

(C) Fernando Lopez-Lezcano 2013EMW 2013

concerts

● “From Constantinople to California”

(C) Fernando Lopez-Lezcano 2013EMW 2013

concerts

● “From Constantinople to California”

(C) Fernando Lopez-Lezcano 2013EMW 2013

concerts

● “From Constantinople to California”

a demo.... just stereo, so in no way this represents

the feeling of being in the transformed space

(C) Fernando Lopez-Lezcano 2013EMW 2013

before the concert...

(C) Fernando Lopez-Lezcano 2013EMW 2013

before the concert...

● loudspeaker location plans, cabling plans● managing inputs and outputs● (software development)● speaker rigging and cabling...● measuring speaker distances and level● measuring impulse responses for DRC● sound tests, tweaking● creating of ardour sessions for each piece● rehearsals

(C) Fernando Lopez-Lezcano 2013EMW 2013

before the concert

(C) Fernando Lopez-Lezcano 2013EMW 2013

before the concert

(C) Fernando Lopez-Lezcano 2013EMW 2013

before the concert

(C) Fernando Lopez-Lezcano 2013EMW 2013

before the concert

(C) Fernando Lopez-Lezcano 2013EMW 2013

future

● including DRC into the system

– first successful test in the Transitions 2013 concert

● integration of several systems into supercollider

– ambisonics decoding (using ADT and a GUI)

– partitioned low latency convolution for DRC

● design a GUI in SuperCollider for better feedback

– banks of level meters

– automatic calibration routines

– routing

(C) Fernando Lopez-Lezcano 2013EMW 2013

questions?

(C) Fernando Lopez-Lezcano 2013EMW 2013

thanks!