How To Set Up A Crossover For Live Sound
If you lot accept been tasked with setting upwards a sound organization for a small band that wishes to achieve an audience of 300 to 500 people, there are various elements, both strategic and technological, to consider. Audio tech people have never had such a broad range of sound reinforcement equipment and techniques at their disposal. The choices of technology and products available tin be overwhelming, so let's talk about some of the options.
Speaker Choice
Your choice of speakers should be based on coverage requirements and the size of the venue. There are some things to consider regarding the shape of the room and how the speakers will interact with boundaries, such as the walls, the ceiling, and the floor.
You want to get the best speakers your budget will allow. Start past figuring out what you can afford and then determine what sounds best to yous within that price range. Ever mind to the speakers before buying, equally not all of them are made equal. When choosing a speaker, you'll want to consult the specification canvas, which should exist readily available from about reputable manufacturers. The near important specs to know are the frequency response, SPL output, and dispersion. If you are using passive speakers, and then yous'll demand to know the wattage and impedance (ohms resistance).
A full-range speaker with a frequency response of lx Hz to 18 kHz may be fine for many genres of music, such as land, folk, or folk-rock, where the kicking drum and bass don't need additional punch. For rock, metal, pop, hip hop, EDM, etc., you will desire a subwoofer. A subwoofer extends the frequency response downwardly to 45 Hz or lower and will allow the full-range speakers additional headroom and increased output. ;
The sound pressure level of a speaker will determine how loud a speaker is at a given distance (typically ane meter). Most spec sheets will bear witness Peak and Continuous outputs. The acme is how loud the speaker is on loud transients, while continuous output is the average loudness. This is a good indication of how the speaker performs, dynamically. Sound pressure levels (SPL) volition benumb past half-dozen dB with the doubling of the distance. If a speaker were capable of 135 dB at 1m, then 2m would have an SPL of 129 dB. By doubling the distance to 4m, the speaker would output 123 dB and so on. Some other consideration is that doubling upwardly on the speakers volition result in a +3 dB increase. If a speaker has a elevation output of 135, by adding some other speaker the output would increase to 138 dB.
Dispersion is the way the sound is projected horizontally and vertically from the speaker. This is incredibly useful for determining the placement of speakers, as yous can direct the audio away from boundaries, such equally walls and ceilings. For instance, a speaker with a 60-caste horizontal dispersion might piece of work well for a narrow room, while calculation an additional speaker could increase the dispersion to 120. The goal is to offering coverage to the entire audition, while directing the sound off the walls. Many speakers are designed to couple past utilizing a trapezoidal enclosure, versus a square or rectangular enclosure. The trapezoidal design allows for easy placement of the speakers, as they can be placed together in tight-knit grouping or array, which allows for coupling with reduced interference between speakers.
The vertical dispersion volition determine how high the full-range tops will need to be to provide proper sound coverage for the audition. At that place are many means to configure a system, in terms of elevation and whether ground-stacking, speaker stands, scaffolding, or trussing should be implemented as a way to get the speaker high enough to offering extended coverage. The higher the speaker, the farther the sound will travel. If it is too high, there will be a loss of bear on in the forepart. Not high enough may upshot in the sound being uncomfortably loud for the front row.
For our purposes, I advise setting the tops at shoulder to head level, near 5 to 6 feet from the flooring. If you are utilizing subwoofers, you might attempt ground-stacking the tops on tiptop of the subs. Many speakers offering pole mounts for use with speaker stands. This is the simplest style to become proper height, especially if yous don't take multiple subs to create a ground stack. At the very least, y'all want your high-frequency driver to a higher place the heads of the people in the audience.
Active versus Passive
There are pros and cons to both agile and passive speaker designs. Agile speakers are the easiest to deploy with congenital-in amplifiers that are matched to the speaker components (woofers, mid-range, and tweeters—typically pinch drivers). They also feature crossovers, which isolate and route frequency ranges to each component, and built-in limiters for protecting the drivers. A three-way agile speaker will have ii or more built-in crossovers, which isolate the loftier, mid, and depression frequencies. The reward of active speakers is the ease of setup and operation. They just crave a line level input and you won't accept to utilise divide amplifiers to power them.
Passive speakers require distension, speaker cables, and may crave an outboard crossover and other signal processing. Some passive speakers volition utilize an internal crossover network, which functions much like the active speakers. Other speakers are designed to exist bi-amped or tri-amped, which can be a benefit, as this allows greater control over the speaker components, but besides requires a separate amplifier for each component of the speaker. If you decide to go with a passive speaker design, you'll need to expect at the specification sheet provided by the manufacturer to determine the right amplifier(south).
The input range of a speaker is typically given in continuous, program, and acme wattage measurements. You lot will almost probable see the continuous output and either plan or peak. The full general rule is a doubling of the continuous results in plan, while doubling the program will give the height functioning. For instance, allow's say we have a 4-ohm speaker that requires 600 watts of continuous output, a programme output of 1,200 watts, and a peak output of 2,400 watts.
The question that many people ask, is how much power do I need? Do I really demand a two,400-watt amplifier to power this speaker? The answer depends on your total required SPL output. Looking at the speaker's specifications. We see it offers a continuous SPL output value of 128 dB and a peak SPL output of 134 dB. Let'south say you want an SPL output of 105 dB at 50' from the speaker. Think every doubling of the distance, lowers the SPL by 6 dB. The speaker's programme output requirement is 131 dB at 1m. sixteen meters or 52.8 feet would offer an SPL of 107 dB, therefore you can safely use a 1,200W ability amplifier to achieve your target. If we doubled the program output of 1,200 watts to 2,400 watts, you would gain an additional 3 dB. My opinion would exist to purchase more power than needed to maintain headroom. This, of course, comes down to budget, because some speakers may require up to 11,000 watts peak output, which would push you into another class of amplification with a much higher toll tag.
Another consideration is the impedance or ohms resistance for the speaker. Yous will demand to consult the amplifier specifications to determine how much power an amplifier is able to produce at a given impedance. Almost manufacturers will boast the highest output of both channels at the lowest resistance. When matching your amplifier to your speaker, it's important to consider the ohms rating and wattage. For instance, an amplifier that is rated at iv,000 watts (2,000 watts per aqueduct) at ii ohms will realistically deliver 1,400 watts at four ohms and 850 watts at 8 ohms. Our example speaker has a four ohm impedance, which can easily be powered by our four,000-watt amplifier.
Some amplifier manufacturers will indicate power draws every bit ane/8 ability, ane/three ability, and full power. 1/8 ability delivers the amplified betoken below the built-in clip limiters, while one/3 power will have the clip limiters occasionally flashing. Full power will accept the limiters in abiding activity. When engaging the clip limiters, y'all are actually rounding off the audio signal to prevent distortion, but the indicate of the sound will be compromised. I prefer to run the amplifiers at 1/8 ability, which volition requite plenty of headroom without squaring off the waveforms. You may also employ a college-rated amplifier at 1/8 power without fear of damaging your speakers. Remember, the quickest style to blow a speaker is to underpower information technology.
Subwoofers also come in active and passive options with the aforementioned pros and cons. In that location are many unlike designs that tin offer outstanding results. The best bang-for-the-buck I recommend is a Yorkville ES18P. It is a self-powered, single eighteen" rear-horn loaded design with a tremendous output, rivaling or surpassing most double eighteen" designs.
Depending on your setup and how many subs you have, yous will have more consistent results by placing all the subs together. Placing 2 subs together volition yield a 3 dB gain in SPL and they volition couple without interference. A stereo sub configuration may create null points in the room where sure frequencies cancel each other out. Other tricks to maximize bass are to place the subs nearly a wall or corner, as each of the boundaries will reinforce the sound and assist load the room. My favorite configuration is to center-cluster 4 subs together (2 wide x 2 tall).
Speaker Processors
Regardless of whether yous are using agile speakers or passive speakers with an amplifier, you should invest in a speaker processor. In my opinion, it is the about important piece of gear and will save you fourth dimension, money, and headaches. A speaker processor combines a number of processors into a rackmount bespeak processor. Yous will notice gain, EQ, delay, crossovers, and limiting for both input and output. A typical processor might have a stereo input and half-dozen outputs. The inputs will characteristic a 6- to 8-band parametric EQ and/or a graphic EQ, as well every bit a arrangement delay. Each output on your processor will offering gain, a 4-band parametric EQ, a delay for time-aligning speaker components in a bi-amp or tri-amp awarding, or a total-range speaker and a subwoofer.
Y'all will besides find digital crossovers featuring Bessel, Butterworth, and Linkwitz-Riley ring-pass filters. Each crossover offers a high-frequency and low-frequency setting with selectable filter types. For tops, I typically prepare the HPF to 96 Hz on a 24 dB per octave Linkwitz-Riley filter and the LPF to off. For subs, I set the LPF to 96 Hz on a 24 dB per octave Link-Riley filter and the HPF to 30 Hz on a 48 dB Butterworth filter. The major focus is the crossover between the LPF of the sub and the HPF of the top. A 24-dB-per-octave Link-Riley filter keeps the frequency response flat where both the subwoofer and summit are crossing over.
Annotation: A speaker processor delay is non a digital delay effect, as information technology is intended to literally delay a point by a set amount and does not offer a "wet/dry" setting. If a manufacturer offers time delay settings for your speakers, y'all tin can use those to time marshal the tops and subs. The LS-801P has a three ms delay, and so adjusting the tops to lucifer the inherent delay of the subs volition provide a coherent and phase-accurate moving ridge front. If you don't have the specs, you can invest in a measurement organization like SMAART. If you take an iPhone or iPad, you lot can purchase the AudioTools app by Studio Half dozen Digital, which tin help y'all measure and calibrate your sound organisation.
Analog Mixers versus Digital Mixers
Analog mixers are the mainstay of any audio system, and range in price and features. At that place are some diehard analog enthusiasts who will not movement to a digital mixing lath, as they believe the analog components sound superior to digital. If you are mixing a alive band, you will want some boosted signal processors to shape the sound of each instrument. About analog mixing consoles will offer a built-in four band parametric EQ, which helps balance the tonal sound and carves out space for each instrument in the mix. It is rare to find analog consoles with congenital-in dynamics bachelor on every channel. Therefore, an all-analog setup will require several racks of gear to suit the additional signal processing, such as compression and gates for each channel.
Another aspect to consider is the use of wedge monitors or phase monitors. These are speakers that are typically on the floor and angled up toward the performers, offering a dedicated mix, which allows the musicians to hear themselves on stage. Feedback can become a problem, so the use of graphic EQs will be needed to remove the frequencies that are feeding back. Add in additional signal processors like multi-effects, delays, and reverbs and you lot can see the analog setup may audio meliorate, but will cost more coin with the additional signal processing, plus there are additional racks, cabling, troubleshooting, and maintenance involved.
Digital mixers have fabricated some considerable advances in recent years regarding the quality of the sound, and pricing that is comparable to many moderately priced analog consoles. Digital mixers offer the best solution for whatever touring band, with a large channel count and each channel packing four-band EQ, pinch, and gating. Additionally, each output features graphic EQ for ringing out monitors. Many mixers feature internal effects with upwardly to eight insert slots for use with internal sends. You tin can still use your favorite outboard gear, merely the digital platform reduces the amount of gear substantially. Another benefit of the digital mixer is the wireless control options. Many mixers offering iOS and Android control apps.
If the FOH position is in a less than desirable place, the engineer can move well-nigh the room to make informed adjustments based on the audition's perspective. This also allows the engineer to tweak monitors from the stage, while standing adjacent to the musicians. Many mixer platforms will permit multiple device setups in which ring members may arrange their ain mix in existent time, assuasive the FOH engineer to focus on the chief mix. Other features now incorporated in the digital platform include spectral assay and a existent-fourth dimension analyzer (RTA) for making adjustments to monitors or to the unabridged mix. However, I nonetheless recommend a dedicated speaker processor for tuning the sound organisation.
Phase Snakes and Stage Boxes
A stage box or multi-channel ophidian is highly beneficial for reducing clutter on the stage. Some larger stage setups use a splitter that splits the signal from all the sound sources on stage between FOH and monitors. Most mid-level bands typically don't have a dedicated monitor engineer, so the FOH engineer will perform both main mixing and monitor duties. With an analog setup, you'd be working with a 16- to 24-channel audio snake with a cable run of 100+ feet. A drum kit may have viii to 12 microphones ready to capture the audio, then a dedicated sub-serpent allows for shorter mic-cable runs and a much cleaner stage setup.
Utilizing stage sub-snakes before going to the main stage snake will keep the cable clutter on phase to a minimum. Many digital mixers offer digital stage boxes that function like an analog stage snake, only instead of a 16- to 24-pair multi-aqueduct cablevision, the digital snake will use a single CAT5 cable to connect to the mixer in the FOH position. This cuts downward considerably on the weight and setup fourth dimension of the unabridged organisation.
Microphones
For musicians to be heard, microphones are used to capture vocals, guitar amplifiers, and drums. The mainstay of live music is the use of dynamic microphones. There are many microphone manufacturers, but the favorite of most clubs is nonetheless the Shure SM58 for vocals and SM57 for instruments. They have proven their value over fourth dimension past sounding good and being incredibly rugged. They can literally take a beating and still office. If there is the budget and want for wireless microphones, I highly recommend the Shure GLXD or QLXD series digital microphones. The GLXD is an affordable option with a clean, clear sound without any artifacts, a simple setup, and a congenital-in charger in the receiver.
In-Ear Monitors
Many bands prefer to forgo the use of phase monitors and opt for in-ear-monitors (IEM). I've used the entry-level PSM300 Shure Personal Monitoring Organization for years and take had splendid results. With a digital mixer, the setup and functioning is even simpler, resulting in very happy musicians who are able to prepare their own monitor mix—and without excessive stage volume.
In Decision
As you can see, there are many directions one tin choose when setting upward a sound system for your band or event: analog mixers versus digital mixers; passive speakers and subs versus active designs. Each has its pros and cons. The most important matter is to use your ears when making decisions. Always heed to speakers earlier purchasing and, if possible, demo speakers and subs together, particularly if you are using dissimilar brands. I can't recommend enough the importance of having a dedicated speaker processor for whatever arrangement, regardless of size or budget.
Source: https://www.bhphotovideo.com/explora/pro-audio/buying-guide/live-sound-101-sound-system-design-and-setup-live-band
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