Isolation cabinet (guitar)

Isolation cabinet (guitar)

The characteristic sound of a tube guitar amplifier as heard on the majority of professional recordings is achieved by playing the amplifier at high volumes, and using one or more microphones to capture the sound. Turning the volume up causes the pre-amplifier to drive the power amplifier into distortion and the loudspeaker to "break up", adding crunch and grit to the amplified tone. The speaker cone also generates more sound pressure, delivering more dynamic range and detail to the microphone.

However, an amplifier at full volume is extremely loud, posing a risk to hearing and an annoyance to neighbors, and will often drown out other instruments in a mix. A guitar speaker isolation cabinet is a sound-proof enclosure that surrounds, at minimum, the speaker and microphone and prevents sound leakage into the outside environment, enabling the amplifier to be turned up without excessive listening volume.

izes and types

A guitar speaker "isolation cabinet" has a built-in mounting baffle for a guitar speaker and a permanently mounted microphone clip. A compact isolation cabinet contains a small guitar speaker such as 6 1/2" diameter and sometimes an attached power attenuator to prevent blowing the speaker.

A guitar speaker "isolation box" is large enough to contain a standard guitar speaker cabinet such as a 1x12" or 2x12" cabinet and a couple of compact microphone stands. Inexpensive but less effective implementations of this approach are to bury a guitar speaker and microphone in a closet, place gobo partitions around a speaker cabinet to somewhat deflect the sound, or form a tent with multiple layers of heavy blankets over a guitar speaker cabinet and microphone.

A "isolation booth" is a small room large enough to contain a single performer and his rig, enabling the instrument to interact with the amplifier while isolating the rest of the band from the extreme volume.

Finally, the "live room" of a recording studio provides sound isolation between an entire band and the control room, allowing the studio engineers to work at manageable volumes and prevent ear fatigue.

The frequency response of an isolation system depends on the number of microphones, the type of microphones, microphone positioning, cabinet dimensions, speaker size, speaker model, and the amount of sound-absorption material inside the speaker cabinet. To control the resulting response, a dedicated equalizer can be used to enhance or reduce specific frequency ranges.

Degree of sound isolation

A single-layer isolation cabinet or isolation box reduces the sound but does not make the speaker silent; significant bass leaks out. A double-layer box with dead space between the layers still leaks audible bass, if typical plywood thickness is used. Getting closer to silencing would require two very massive layers of plywood, MDF board, or soundproofing board such as Homasote or Wonderboard. An additional layer may be needed, such as for a 100-watt guitar amp with multiple efficient guitar speakers inside the box.

Combined approaches

To reduce the volume leakage or to prevent blowing the speaker or microphone, a power attenuator is sometimes used between the tube power amp and the guitar speaker in the isolation box. This reduces the power delivered to the speaker and thus the volume, but has some effect on speaker and microphone response.

To reduce volume on stage while staying near to a traditional guitar amp setup, a guitar amp can drive two parallel loads: a power attenuator driving a conventional guitar speaker cabinet (with no microphone), and a speaker isolation cabinet providing the signal for the mixer board and sound reinforcement system.

Overstressing components

Blowing a speaker is a significant possibility when using an isolation cabinet.Fact|date=January 2008 A blown speaker usually has a broken wire in the coil and would need to be reconed. A blown speaker appears as an open or infinite resistance to the tube power amplifier and can "fry" expensive components in the amp, such as the output transformer or power tubes, which would then need to be replaced.

"Cranking an amp" means turning up a guitar power amplifier well into the region at which power-tube distortion is produced, generating as much as twice the amplifier's rated non-distorting wattage. Pushing a guitar amp to such an extent can destroy components of an amplifier whether using an isolation cabinet, dummy load, power attenuator, or conventional guitar speaker cabinet. In particular, tubes wear more quickly when they are consistently pushed into saturation.

ee also

*Guitar speaker cabinet
*Guitar speaker
*Guitar amplifier
*Power attenuator (guitar)
*Recording studio
*Bass instrument amplification
*Sound baffle
*Distortion (guitar)
*Electric guitar

External links

* [ Amptone] - list of isolation cabinet products, and do-it-yourself isolation cabinet projects

* [ Grendel Sound] - Manufacturers of the Dead Room speaker isolation cabinet.

Wikimedia Foundation. 2010.

Look at other dictionaries:

  • Guitar speaker cabinet — A guitar speaker cabinet contains one or more guitar speakers as many as eight, often 8 or 10 types. A speaker cabinet can be open back, sealed or vented. A 4x12 cabinet is a guitar speaker cabinet containing four 12 speakers. A cabinet is… …   Wikipedia

  • Guitar speaker — A guitar speaker is a loudspeaker – specifically the driver (transducer) part – designed for use in or with the guitar amplifier of an electric guitar. Typically these drivers produce only the frequency range relevant to guitars which is similar… …   Wikipedia

  • Guitar amplifier — Mesa Boogie Mark IV, a guitar combo amplifier A guitar amplifier (or guitar amp) is an electronic amplifier designed to make the signal of an electric or acoustic guitar louder so that it will produce sound through a loudspeaker. Most guitar… …   Wikipedia

  • Guitar effects — are electronic devices that modify the tone, pitch, or sound of an electric guitar, or condition or reroute the signal in some fashion. Effects can be housed in small effects pedals ( stomp boxes ), guitar amplifiers, guitar amplifier simulation… …   Wikipedia

  • Power attenuator (guitar) — In electric rock guitar, attenuators are used to dissipate some or all of the amplifier s power in the attenuator s built in, mostly resistive dummy load instead of letting that power drive the speaker, in order to silence or reduce the output… …   Wikipedia

  • Recording studio — Further information: Movie studio, Studio, and Television studio Studio control room with a mixing console, monitor speakers, and MIDI workstation. A recording studio is a facility for sound recording and mixing. Ideally both the… …   Wikipedia

  • Bass instrument amplification — for the bass guitar, double bass and similar instruments is distinct from other types of amplification systems due to the particular challenges associated with low frequency sound reproduction. This distinction affects the design of the… …   Wikipedia

  • Instrument amplifier — This page is about amplifiers for musical instruments. See also instrumentation amplifier, a type of operational amplifier. An instrument amplifier is an electronic amplifier that converts the often barely audible or purely electronic signal from …   Wikipedia

  • Re-amp — Reamping is a process often used in multitrack recording in which a recorded signal is routed back out of the editing environment and run through external processing or reverb chamber. Originally, the technique was used mostly for guitars: it… …   Wikipedia

  • Jim Root — Este artículo o sección necesita una revisión de ortografía y gramática. Puedes colaborar editándolo (lee aquí sugerencias para mejorar tu ortografía). Cuando se haya corregido, borra este aviso por favor …   Wikipedia Español