Den stora Thomann Online-Rådgivaren: Choosing a PA System

7. Loudspeakers

No matter how good the rest of the system may be, it can all fall apart at the loudspeakers. There's no digital or analogue debate in this area - it's here that the electrical signals have to be converted to waves of air and pushed out to the waiting audience. Because of this, the speaker cabinet is as important as the ‘drivers’ themselves in the management and diffusion of the sound. You can get deeply immersed in speaker technology if it takes your fancy - our Online Guide to PA Speakers is a good place to start - but here we'll just consider the essential points.

The first issues concern compatibility with the amplifier:

  • The impedance (a kind of electrical resistance, measured in Ohms) of the speakers must match the range of output impedances that the amplifier can handle. Each speaker will usually be rated at 4 Ohms or 8 Ohms. Resistance is a tricky principle, and much depends on exactly how you will connect everything together. The key point is that an imbalance can damage speakers, amplifier, or both, so check the specifications of each element to ensure that they are compatible. Above all, make sure the total impedance of the speakers is within the operating range of the amp. See our Online Guide to PA Amplifiers for more on calculating this.

  • Remember the rule about Watts RMS - match the speaker capacity to the output of the amplifier, allowing about 30% more power from the amp. The idea is that you don't run everything at full volume, but you have enough headroom to cope with the highest peaks.
A typical PA speaker cabinet, with low/mid-range and high frequency speakers

Frequency range

This is an important measure for musicians in particular, because it indicates the most suitable use for a speaker. Is it good for high, mid, or low-frequency sound? Most people can hear sound in the range between 20Hz and 20,000Hz (Hz = cycles per second). The ideal loudspeaker would be able to transmit effectively across the entire frequency range, although in practice this is virtually impossible.

So the key question is whether or not the loudspeaker can transmit consistently and with good quality, within its ideal frequency range. This is known as linear transmission. For the purposes of a general gigging PA, you will need a combination of speakers that offer a broad coverage of the frequency range.

The industry uses frequencies separated by a musical third, and the levels are expressed in decibels (dB). Typically, if a frequency response is shown as 40 - 20,000Hz, +/-3dB, you can assume that the bass frequencies were raised at around the +3dB level, and that the higher frequencies were dampened at around -3dB. The usual warning about manufacturer data always applies - they will tend to use the figures that flatter their equipment, though most reputable companies will show fairly accurate frequency response data and RMS values.

Sound pressure

Sound pressure means volume - the higher the pressure of the sound wave striking your ears, the louder it sounds. It’s measured, perhaps appropriately, in Pa (short for Pascals in this case - strength per unit area).

In fact, humans have a fairly limited audible range, from around 100Pa (the pain threshold for most of us) to about 20uPa. The ear detects these as logarithmic values, measured in deciBels. Zero dB roughly equates to 20uPa, and it usually starts to hurt for us at around 130dB. When considering speakers, the sound pressure level (SPL) is usually shown in decibels. For example a speaker may be shown as 400W RMS, 118dB SPL.

Not all manufacturers use the same measures, but what you are looking for is an indication of how much of the signal received is converted faithfully to moving air. The higher the number, the greater the efficiency and/or sound pressure produced by the speaker. If, for example, you compare two speakers that have a difference of 3dB in their sound pressure ratings, then you can assume that you will need roughly twice the power to achieve the same volume from the unit that is lower rated, and therefore less efficient.

Active loudspeakers

For smaller venues, active loudspeakers are often a cost-effective option. These have amplifiers built-in – you simply connect them directly to a mixer. Typically, the active loudspeaker cabinet will contain mid-range and high frequency speakers. If you are connecting keyboards, or amplifying the bass drum, it's worth adding at least one sub-woofer cabinet to handle the bass frequencies. In these configurations, the bass cabinet will usually contain a crossover switch to distribute the frequencies between the appropriate speakers.

Din kontaktperson
PA
Tel +49-9546-9223-35
Fax +49-9546-9223-24
Hot Deals Beställ en gratis Hot Deal!

Över 9.000.000 musiker prenumererar redan på Thomann Hot Deals. Börja prenumerera gratis och få tillgång till mer än 400 aktuella erbjudanden!

Choosing a PA System översikt

Schoeps CMC54 Mono Set MK4 CMC5 Adam T5V Subpac M2X Marshall Origin 20C Combo Yamaha Stagepas 600BT Roland R-07 black RME ADI-2 DAC Focal Listen Professional Fender Squier Affinity P-Bass PJ ILBK Epiphone Richie Faulkner Flying V Yamaha Stagepas 400BT Fender SQ Affinity PJ Bass Pack BK 18
(1)
Rekommenderat
Schoeps CMC54 Mono Set MK4 CMC5

Schoeps CMC54 Mono Set Limited Edition, high quality condenser small diaphragm microphone comprising CMC 5 mic preamp Refurbished (new housing and refurbished) and MK4 capsule (new) cardioid, specifications CMC 5: power consumption 4mA, 48V phantompower, max. output level 1V, length...

Till produkter
990 €
(3)
Rekommenderat
Adam T5V

Active Nearfield Monitor Equipped with: 5" woofer and 1.9" U-ART ribbon tweeter, 2x Class-D amplifiers: 50W RMS woofer, 20W RMS tweeter, Frequency range: 45 - 25000 Hz, Crossover frequency: 3 kHz, Maximum input level: 106 dB (1m/pair), Rear bass...

Till produkter
169 €
Rekommenderat
Subpac M2X

Subpac M2X, Mobile tactile bass system, SubPac adds real depth, connection and enjoyment to whatever you play through it - your music and media comes to life with the added dimension of physical bass. Frequency Response: 1hz-200hz, Wired Input: 3.5mm...

Till produkter
399 €
Rekommenderat
Marshall Origin 20C Combo

Tube combo amp for electric guitar Gain boost function, Two voicings (Normal, High Treble), which can be mixed steplessly via the tilt control, Switchable power reduction for full sound in any environment, 1 channel, Power: 20 watts, Preamp tubes:...

Till produkter
645 €
Rekommenderat
Yamaha Stagepas 600BT

Mini-PA System with Bluetooth Function Consisting of 2x passive 2-way boxes and 10-channel power mixers, Power mixers and speaker cables can be stored in the boxes for transportation, Successor of the Stagepas 600i, Including 2 speaker cables, each 6...

Till produkter
798 €
(1)
Rekommenderat
Roland R-07 black

Portable MP3 / WAV Recorder with Bluetooth Functionality Stereo recordings up to 24 Bit / 96 kHz in WAV format or up to 396 kbps in MP3 format on microSD / SDHC card, Built-in stereo microphone, Integrated hybrid limiter,...

Till produkter
229 €
(3)
Rekommenderat
RME ADI-2 DAC

High-end DA converter & headphone amplifier Sample rates: 44.1 kHz up to 768 kHz, Playback of DSD and Direct DSD, SteadyClock FS, LCD display with AutoDark function for lighting, Desktop Case, Dimensions: 215 x 52 x 150 mm, Weight:...

Till produkter
999 €
Rekommenderat
Focal Listen Professional

Headphones Closed, Circumaural, Conversion technology for acoustic transparency and dynamics, Impedance: 32 ohms, Sensitivity (@ 1 kHz - / 1 Vrms): 122 dB SPL, THD (THD, @ 1 kHz / 100 dB SPL): 0.3%, Frequency range: 5 Hz to...

Till produkter
248 €
Rekommenderat
Fender Squier Affinity P-Bass PJ ILBK

Electric Bass Affinity series, Body: Alder, Neck: Maple, Fretboard: Indian Laurel, Neck profile: "C", 20 Medium jumbo nut, Scale: Long scale, Nut width: 41.3 mm, Pickups: 1 Jazz and 1 Standard Split Precision single coil, 2 Volume and 1...

Till produkter
238 €
(1)
Rekommenderat
Epiphone Richie Faulkner Flying V

Electric Guitar Body and neck: Mahogany, Fretboard: Ebony, Neck profile: Thin C, 22 Jumbo frets, Scale: 628 mm, Pickups: Active EMG 57 (bridge) and EMG 66 (neck) humbucker, Floyd Rose 1000, Grover Rotomatic machine heads, Colour: Black, Incl. Deluxe...

Till produkter
935 €
(1)
Rekommenderat
Yamaha Stagepas 400BT

Mini-PA System Bluetooth Function Consisting of 2x passive 2-way boxes and 8-channel power mixers, Power mixers and speaker cables can be stored in the boxes for transportation, Successor of the Stagepas 400i, Including 2 speaker cables, each 6 m...

Till produkter
555 €
Rekommenderat
Fender SQ Affinity PJ Bass Pack BK 18

Fender Squier Affinity PJ Bass Pack BK bass guitar set with bass, rumble 15 amp, cable and strapt; bass guitar, poplar body, maple neck, indian laurel fretboard, 20 medium jumbo frets, nut width 41,3mm (1,625"), scale 864mm (34"), pickups 1x...

Till produkter
279 €
Feedback Har du hittat ett fel eller vill ge oss feedback om denna sida?

Vi ser fram emot att höra från dig och kommer att lösa eventuella problem så snart vi kan.

Lämna kommentar. Ange din e-postadress.