Abstract:
An apparatus for combining input signals produced by a plurality of electric musical devices includes a plurality of audio buses and a plurality of segments. Each segment includes input circuitry configured to receive at least one input signal from at least one electric musical device and to deliver the at least one input signal to one of the plurality of audio buses; a plurality of variable adjustment devices each associated with a corresponding one of the audio buses and each configured to change at least one property of an input signal received by another of the plurality of segments and carried on the corresponding one of the audio buses independent from input signals carried on other of the plurality of audio buses; and a mixer configured to combine the input signals carried on each of the plurality of audio buses into an output signal.

Description:
CROSS-REFERENCE TO RELATED APPLICATION PARAGRAPH 
     This application is a continuation of and claims the priority of U.S. application Ser. No. 12/466,311 filed on May 14, 2009, which claims the benefit of U.S. Provisional Application No. 61/053,391 filed on May 15, 2008, the contents of the applications are hereby incorporated by reference in their entirety. 
    
    
     FIELD OF THE INVENTION 
     The invention relates to systems for combining inputs from musical instruments (such as electronic and electro acoustic instruments) and similar devices. 
     BACKGROUND 
     Electric and electro-acoustic musical instruments, such as an electric guitar, an acoustic guitar with a pickup, an electric bass, and microphones rely on electronics, such as amplifiers, to amplify and/or modify their sound. In a setting with multiple musicians, such as a band rehearsal, each musician may have an amplifier, and the band as a whole may have mixers to control and monitor the output of the band as a whole. For instance, products such as the Rolls MX41 mixer or the Mackie 1202 accept multiple input channels, allow manipulation of each input, and generate one audio mix. 
     Often, it is desirable for a band rehearsal to be conducted “silently;” that is, to feed the band&#39;s sound into headphones such that the instruments make minimal acoustic sound. Headphone amplifiers can enable silent rehearsals: these devices accept multiple inputs, combine the inputs into one output signal, and feed the output signal into headphones worn by each musician. However, headphone amplifiers do not allow each musician individual control over the constituent parts of a particular mix of inputs that feeds into his headphones. Rather, a common mix is generated by a separate piece of equipment (a “mixer”) and that same mix is directed into each musician&#39;s headphones or other listening device. At most, some headphone amplifiers, manufactured for example by Samson and PreSonus, allow a musician to increase the volume of his own input channel (the “More Me” concept) within his own set of headphones. Even with headphone amplifiers, however, a common mix is still created prior to the headphone amplifier so that a change in the overall mix impacts all listeners; individual modifications to other input channels are not possible with headphone amplifiers and mixers used together. 
     SUMMARY 
     In one general aspect of the invention, an apparatus includes a plurality of audio buses and a plurality of segments. Each segment includes input circuitry configured to receive at least one input signal from at least one electric musical device and to deliver the at least one input signal to one of the plurality of audio buses; a plurality of variable adjustment devices each associated with a corresponding one of the audio buses and each configured to change at least one property of an input signal received by another of the plurality of segments and carried on the corresponding one of the audio buses independent from input signals carried on other of the plurality of audio buses; and a mixer configured to combine the input signals carried on each of the plurality of audio buses into an output signal. 
     Embodiments may include one or more of the following. The at least one property of the input signal includes the gain of the input signal. The input circuitry includes circuitry for adjusting at least one property, e.g., the gain, of the at least one input signal prior to delivering the at least one input signal to one of the plurality of audio buses. The input circuitry includes circuitry for adjusting the proportion of the at least one first input signal delivered to each of a first channel and a second channel of the first audio bus. The apparatus includes output circuitry configured to adjust the volume of the output signal and to deliver the output signal to an output device, e.g., a set of headphones or a digital recorder. The apparatus includes a phantom power switch. The plurality of audio buses and the plurality of segments are contained within a housing; for example, the plurality of channels are arranged radially within the housing. The housing is portable At least one of the segments is remotely operable. The apparatus includes a docking station. 
     In another aspect, the invention relates to a method for combining input signals produced by a plurality of electric musical devices. The method includes receiving a plurality of input signals into a corresponding plurality of segments; directing each input signal into an audio bus; and, for each segment, adjusting at least one property of each input signal independently from each other input signal and independently from each other channel and combining the plurality of input signals into an output signal. 
     Embodiments may include one or more of the following. The at least one property of the input signal includes the gain of the input signal. The method includes adjusting the gain of each input signal before directing each input signal into an audio bus. Directing each input signal into an audio bus includes adjusting the proportion of the input signal sent to each of a first channel and a second channel of the audio bus. The method includes adjusting the volume of the output signal and delivering the output signal to an output device, e.g., a set of headphones. 
     An apparatus including a plurality of audio buses and a plurality of segments has advantages for groups of musicians who need to rehearse together “silently,” making only minimal acoustic sound, for instance because the noise from a loud rehearsal would disturb neighbors. The apparatus allows each musician to control the combination of channels he or she hears independently of the combination heard by each other musician. This capability enables more productive rehearsals as each musician can generate a combination that best suits his or her musical needs or preferences. The operation of the apparatus is straightforward and can be done by the musicians themselves during the rehearsal or performance of a piece of music without the need for a sound engineer or technician. Furthermore, the apparatus may be connected to devices such as a digital music recorder or a computer, allowing the rehearsal to be recorded and allowing the combination of channels recorded to be adjusted. Currently available devices do not provide each musician with the capability of independently adjusting what he or she hears. The apparatus described above is also light and portable, allowing it to be used easily in a variety of locations, such as in rehearsal studios, homes, schools, dorm rooms, and performance venues. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a cartoon depiction of a group rehearsal system. 
         FIGS. 2 and 2A  are schematics of the external structure of the rehearsal system. 
         FIG. 3  is a block diagram representation of the rehearsal system. 
         FIG. 4  is a schematic of the electronic circuitry of the rehearsal system. 
         FIG. 5  is a schematic of another embodiment of the rehearsal system. 
         FIG. 6  is a schematic of the electronic circuitry of the rehearsal system shown in  FIG. 5 . 
         FIG. 7  is a schematic of an embodiment of the rehearsal system in which one or more channels are remotely operable using a remote control. 
         FIG. 8A  is a schematic of an embodiment of the rehearsal system including a docking station. 
         FIG. 8B  is a block diagram representation of features of the docking station. 
         FIG. 9  is a block diagram representation of a rehearsal system including a room simulation module. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     Referring to  FIG. 1 , a group rehearsal system  10  is shown. The rehearsal system  10  allows musicians  1 ,  2 ,  3 , and  4  to rehearse together silently, and enables each musician to control independently the “mix,” or combination of instruments he or she hears. In this way, each musician can generate a unique mix that suits his or her needs or preferences without impacting the mix heard by the other musicians. Rehearsal system  10  is composed of multiple channels  12 ,  14 ,  16 ,  18 , and  20  for receiving electronic musical signals or channels. In the example shown in  FIG. 1 , each channel accepts input  22 ,  24 ,  26 ,  28 , or  30  from a different electronic musical device associated with the channel. Here, for example, inputs  22 ,  24 ,  26 ,  28 , and  30  are associated with, respectively, an electric guitar  22   a , a bass guitar  24   a , an electronic drum kit  26   a , an electronic music player  28   a , and a microphone  30   a . Other electronic musical devices, such as keyboards, may also be used. A channel may receive inputs from multiple devices; for example, channel  12  receives inputs  22  and  32  from an electric guitar  22   a  and a microphone  32   a . As described in greater detail below, each channel generates a mix of the inputs received by all the channels  12 ,  14 ,  16 ,  18 , and  20 . Within each channel, the volume of the input to the channel and of the inputs to each other channel can be adjusted independently to generate a unique mix of inputs in each channel. The overall volume of the mix may also be controlled. In some embodiments, other properties of each input, such as reverberation and pan effects, may also be adjusted. The mix of inputs in each channel constitutes an output signal  34 ,  36 ,  38 , or  40  that is delivered to an output device associated with the channel. For example, an output device may be a set of headphones, a computer, a digital recorder, an ear monitor, or a speaker. In some embodiments, rehearsal system  10  may have more or less than five channels. 
     Referring to  FIGS. 2 and 2A , channels  12 ,  14 ,  16 ,  18 , and  20  are arranged radially within rehearsal system  10 . Rehearsal system  10  is connected to a power supply  92 . Each channel contains an input section  50 , a channel control section  74 , a band control section  80 , and an output section  86 . Rehearsal system  10  also contains a global controls section  102 . 
     Referring to  FIG. 2   a , an exploded view of the layout of one channel is shown. Input section  50  may contain one or more mono input channels  52  and one or more stereo input channels  54 , or may contain only one mono input channel or one stereo input channel. Mono input channel  52  contains a first mono input  56  and a second mono input  58 . First mono input  56  is an XLR input for a microphone, and requires a preamp and a trim control  62  to set the gain. An LED  60  associated with mono inputs  56  and  58  illuminates green when an input signal is detected above a minimum threshold, yellow when the gain level of the input signal approaches preamp clipping (e.g., when the input signal is 10 dB below clipping), and red when the gain level of the input signal reaches preamp clipping. LED  60  may be replaced with an LCD screen to communicate information about the gain level of the input signal. Second mono input  58  is a ¼″ TRS jack designed to accept TR and TRS cables. Second mono input  58  accepts input from electronic musical instruments such as an acoustic guitar, an electric guitar amp modeler, a keyboard, a bass guitar, a bass guitar amp modeler, a piezoelectric pickup, or electronic drums. Second mono input  58  may have a trim control and an LED light (not shown) similar to LED  60  associated with first mono input  56 . Second mono input  58  may also have a high impedance switch (not shown) to improve impedance matching of direct input (i.e., input without a preamp) from an acoustic guitar or a bass guitar. Stereo input channel  54  has two stereo inputs  66  and  68 , which are TRS jacks that accept balanced or unbalanced inputs. In another embodiment, a single stereo TRS jack is used. Stereo input  66  is wired to act as a mono input if needed. Stereo input channel  54  also has a gain control  70  and an LED  72  with an operation similar to that of LED  60 . A +4 dbu −10 dbV switch  64  may be incorporated on stereo input channel  54  to allow for varying the nominal (RMS) input voltage of the channel. A similar +4 dbu −10 dbV switch may also be incorporated on mono input channel  52 . 
     Channel control section  74  contains a location control  76  that controls the distribution of input signal between a right and a left channel of the output signal in order to create a pan effect. Channel control section  74  also contains an effects level control  78  for adjusting the levels of the input signal of the channel. For instance, effects level control  78  may adjust the degree of reverberation effects applied to the channel. The channel control may have other controls to affect the input signal of the channel, including equalization controls  77 , an effects type select and level control (not shown), a 75 Hz “high pass” EQ switch (not shown), and other controls. 
     Band control section  80  contains five controls for adjusting the level of the mono input channels and stereo input channels of each channel  12 ,  14 ,  16 ,  18 , and  20  of rehearsal system  10 . For instance, if the exploded section of  FIG. 2A  shows the layout of channel  12 , control  82  adjusts the level of the mono and stereo inputs of channel  14 , and control  84  adjusts the level of the mono and stereo inputs of channel  16 . In general, the number of controls in band control section  80  corresponds to the number of channels of rehearsal system  10 . In cases such as that as shown here where a stereo and a mono channel are combined into one channel, control  80  may adjust the level of both the mono and the stereo input via one control, two controls (one for the stereo input and one for the mono input), or a device with two concentric controls. 
     Output section  86  contains a ¼″ output jack  88  for connecting the mix to an output device and a gain level knob  90  for adjusting the gain of the output. In other embodiments, the output jack may be a ⅛″ TRS, RCA, USB, mini-DIN structure, or other type of connector. 
     Global controls section  102  contains controls that affect all channels equally. A phantom power switch  104  provides 48 V DC power to all mono inputs to power condenser microphones, Direct Input boxes, and devices requiring phantom power. An effects control  106  determines the types of effects, such as reverberation, used by the channels. 
     Referring to  FIG. 3 , the main functional components of rehearsal system  10  are shown for channels  12  and  14 . Other channels  16 ,  18 , and  20  have similar functional components. In channel  12 , an audio electrical input signal  200  enters an input section  202 ; in channel  14 , an audio electrical input signal  210  enters an input section  206 . The input signals may be provided by a variety of devices including a musical instrument, a microphone, or a digital music player; each input section may accept input signals from multiple devices simultaneously. Input sections  202  and  206  allow a user to set the level of the input signal  200 ,  210  to a level that is optimal for the particular input device. 
     Each of the input signals  200 ,  210  passes to a channel control section  204 ,  208  in channels  12  and  14 , respectively. The channel control section  204 ,  208  generates a modified signal  205 ,  209 , respectively, by applying pan control, reverberation, equalization and other effects. Modified signals  205 ,  209  may be identical to input signals  200 ,  210  if a user does not desire modification. The modified signal  205 ,  209  is delivered to an audio bus  212 ,  214 , respectively. Similarly, audio buses  216 ,  218 ,  220  receive modified signals from channels  16 ,  18 , and  20 . 
     The modified signals carried by each audio bus  212 ,  214 ,  216 ,  218 , and  220  enter a band control section  222 ,  224  in channels  12  and  14 , respectively. Band control section  222  creates an individual mix  223  for channel  12  by providing control over the level of signal from each audio bus  212 ,  214 ,  216 ,  218 , and  220  contained in mix  223 . For example, band control section may set the level of the signal from audio bus  212  at 100%, the level of the signal from audio bus  214  at 75%, and the level of the signals from audio buses  216 ,  218 , and  220  at 50%. Likewise, band control section  224  creates an individual mix  225  for channel  14 . The levels of the signals from audio buses  212 ,  214 ,  216 ,  218 , and  220  may be different in mix  225  than they are in mix  223 . Similarly, channels  16 ,  18 , and  20  also have band control sections that create individual mixes of the signals in audio buses  212 ,  214 ,  216 ,  218 , and  220 . 
     Signals representative of mixes  223  and  225  generated in band control sections  222  and  224  are directed into output sections  226  and  228 , respectively. Each output section contains controls to adjust the level of an output signal. For example, a user listening to channel  12  through a set of headphones  230  can hear mix  223  and can vary the overall level of mix  223  using the controls in output section  226 . Similarly, a user listening to channel  14  through a set of headphones  232  can hear and control mix  225 . Each output section also contains various types of external connections, such as a ¼″ TRS jack, a ⅛″ TRS jack, and a USB port for connection to output devices such as set of headphones, a computer, a digital recorder, an ear monitor, or speakers. 
     In some embodiments of rehearsal system  10 , a global controls section  102  is integrated into two or more channels. In this example, global controls section  102  is connected only to channels  12  and  14 ; in other embodiments, global controls section  102  may be connected to some or all of channels  12 ,  14 ,  16 ,  18 , and  20 . Global controls section  102  provides effects such as reverberation to input signals  200 ,  210  and provides non-audio functions such as 48 V phantom power  238 . The input signal  200 ,  210  from each channel  12 ,  14  is sent to global controls section  102 , where a given effect is applied to the signal. Each signal is then directed  236  to the channel control section  204 ,  206  corresponding to its channel of origin, where the level of the signal can be adjusted as described above. In general, effects processors may allow control over all channels equally, such as through global controls section  102 , or through each individual channel, such as through channel control sections  204  and  206 . 
     Referring to  FIG. 4 , a schematic of the circuitry of rehearsal system  10  is shown for channels  12 ,  14 , and  20 . Channels  12  and  14  (and channels  16  and  18 , details of which are not shown for clarity) have mono input channels and have equivalent circuit structure; channel  20  has a stereo input channel. In channel  12 , input section  202  contains an XLR input  402  connected by a ¼″ TRS jack  403 . Input signal  200  passes to a preamp  404  controlled by a gain control  406 . In this embodiment, a pan control  410  in channel control section  204  sets the amount of signal  205   a ,  205   b  sent to the left and right sides, respectively, of audio bus  212 . Other audio buses  214 ,  216 ,  218 , and  220  carry signals from channels  14 ,  16 ,  18 , and  20 , respectively. The signals carried by the audio buses enter band control section  222  of channel  12 . In band control section  222 , a control  422 , such as a potentiometer or an encoder, adjusts the amount of signal from audio bus  212  that will be contained in mix  223 ; similarly, controls  424 ,  426 ,  428 , and  430  adjust the amount of signal from audio buses  214 ,  216 ,  218 , and  220 , respectively, that will be contained in mix  223  of channel  12 . The adjusted signals are combined into mix  223  on a single output bus  432 . Output bus  432  sends mix  223  to output section  226 , where an amplifier  434  controlled by a control  436  adjusts the level of the mix sent to an output connector  438 , for instance, a headphone jack. Channels  14 ,  16 , and  18  have an equivalent circuit structure to that of channel  12 ; in particular, each channel has a unique output bus that allows the mix of each channel to be independent from the mix of each other channel. Channel  20  has a stereo channel that contains two TRS inputs  472  and  474  to accept an input signal. Circuit elements  476  allow input  472  to function as a mono input when no device is connected to input  474 . An input gain control  478  controls amplifiers  473  and  475  to amplify the input signal on both a left  477  and a right  479  channel simultaneously. The signal is then adjusted by a pan control  480 , and arrives at audio bus  220 . The subsequent circuit structure of channel  20  is equivalent to that described above for channel  12 . 
     Other features of rehearsal system  10  are as follows. Input section  50  may contain a built-in drum machine (or MIDI sequencer) with its own channel control section  74  and a dedicated audio bus. Each channel  12 ,  14 ,  16 ,  18 , and  20  may then have a control in the band control section  80  for controlling signal on the drum machine&#39;s audio bus. Likewise, a band control section may be connected to a built-in multi-channel audio recording device in its output section  86  to enable recording of a performance or rehearsal. Electric and bass guitar amplifier modeling capabilities or a MIDI sound module for electronic drums or keyboards may be incorporated into channel control section  74 . A guitar tuner may be included in one or more channel control sections  74  or in global controls section  102 . A cabled or wireless remote control could be used to allow, for example, drummers who are seated far from rehearsal system  10  to access controls of their channel remotely. A gain boost control and foot switch could be included in channel control section  74  to temporarily increase the output of a given channel&#39;s signal, for example to allow for a change in volume for a solo. Rehearsal system  10  could include a power distribution system separate from audio circuitry so that devices requiring AC power could use rehearsal system  10  as a power source. 
     Referring to  FIG. 5 , an alternative embodiment of a rehearsal system  500  has eight channels  512 ,  514 ,  516 ,  518 ,  520 ,  522 ,  524 , and  526 . A global effects processor has an effects control  538  that controls effects applied to signals from all channels and a power control  540  to provide phantom power either to all channels or to only channels with an XLR jack. An LED  542  illuminates when phantom power is provided. Channels  512 ,  516 ,  518 , and  524  have mono input sections and channels  514 ,  520 ,  522 , and  526  have stereo input sections and mono input sections. Each channel has an input section, a channel control section, a band control section, and an output section. The band control section has eight controls  530  for adjusting the level of signal received from each channel, allowing a unique mix to be generated in each channel. Each channel also contains effects controls such as a pan control  532  and a levels control  534 , which adjusts the level of that channel&#39;s signal once returned from the global effects processor. 
     Referring to  FIG. 6 , a schematic of the circuitry of rehearsal system  500  is shown for representative channel  512  and representative channel  514 . Other channels  516 ,  518 , and  524  have a circuit structure equivalent to that of channel  512 ; other channels  520 ,  522 , and  526  have a circuit structure equivalent to that of channel  514 . Many elements of the circuitry of rehearsal system  500  correspond to elements of rehearsal system  10  shown in  FIG. 4 . In channel  512 , an input section  620  includes a  48  V DC phantom power circuit  622 , a switch  624  for turning the phantom power on and off, and an LED  610 . A channel control section  626  contains an effects level control  602  which sends an input signal to an effects processor  604 . The signal exits channel control section  626  and is sent to an audio bus  612 . Rehearsal system  500  contains eight audio buses  612 ,  614 ,  616 ,  618 ,  620 ,  622 ,  624  and  626 , each receiving signal from channels  512 ,  514 ,  516 ,  518 ,  520 ,  522 ,  524  and  526 , respectively. A band control section  636  of channel  512  determines the level of signal from each audio bus included in a mix  638  on an output bus  630 . Output bus  630  sends mix  638  to an output section  640 . Each channel has a separate output bus such that a unique mix of signals can be generated for each channel independent of each other channel. Channel  514  also contains a control  606  that sends an input signal to an effects processor  608 . Channel  514  is depicted with an optional second output  634 , which in this case is a USB audio analog-to-digital device to allow direct-to-computer recording. 
     In the rehearsal systems described herein, the channels are embodied as segments of a main body of the rehearsal system. For instance, referring again to  FIG. 2 , channels  12 ,  14 ,  16 ,  18 , and  20  each constitute a segment of a main body  96  of rehearsal system  10 . 
     Referring to  FIG. 7 , in one embodiment of a rehearsal system  700 , one or more of channels  712 ,  714 ,  716 ,  718 , and  720  are remotely operable using a remote control. When multiple remote controls are used, each remote control is associated with one channel. In the example shown, channels  712  and  718  are controlled by remote controls  722  and  728 , respectively, and channels  714 ,  716 , and  720  are not remotely operable. In other embodiments, other combinations of channels are controlled by remote control. Channel  712  is controlled by remote control  722  which is physically separate from a main body  704  of the rehearsal system  700  and connected to main body  704  via a wired connection  706 . Channel  718  is controlled by remote control  728  which is removable from the main body  704  and which docks into a space  710  in main body  704  where channel  718  would be located. Remote control  728  is also connected to main body  704  via a wired connection  708 . In another embodiment, remote controls  722  and  728  are wirelessly connected to main body  704 . Remote controls  722  and  728  manage the functions of any or all of the input section, channel control section, band control section, and output section of channels  712  and  718 , respectively. For instance, in the embodiment shown in  FIG. 7 , remote control  722  includes band control knobs  780 , an output knob  786 , and an effects return knob  788  that allow for the remote operation of channel  712 . Band control knob  780  contain controls for adjusting the level of the input channels of each channel  714 ,  716 ,  718 , and  720  of rehearsal system  700 . Output knob  786  controls the volume of an output signal sent to an output device, such as headphones. Effects return knob  788  adjusts the levels of the input signal to channel  712 . In some embodiments, at least one of remote controls  722  and  728  also manages the functions of a global controls section  702 . In some examples, electronic musical devices are connected directly into rehearsal system  700 . In other examples, electronic musical devices, such as a drum set or a microphone, are connected into a remote control (e.g., remote control  722  or  728 ) instead of into rehearsal system  700 . 
     Referring to  FIG. 8A , in one embodiment, a main body  804  of a rehearsal system  800  is docked to a docking station  802 , which includes one or more devices that add additional functionality to the basic capabilities of rehearsal system  800 . Docking station  802  is a “direct out” dock which includes connectors (not shown) that allow each channel  812 ,  814 ,  816 ,  818 , and  820  of rehearsal system  800  to send its output mix directly to the docking station. Referring to  FIG. 8B , a hard disk recorder  804  included in docking station  802  provides the ability to record or play back audio recordings through rehearsal system  800 . An array  806  of amplifiers  808  in docking station  802  supplies the ability to drive speakers for a live performance using rehearsal system  800 . A rechargeable battery docking station  810  enables rehearsal system  800  to function without power from an AC outlet. A wireless transmitter  822  and receiver  824  included in docking station  800  control transmitters and receivers associated with channels  812 ,  814 ,  816 ,  818 , and  820  of rehearsal system  800 , enabling the wireless use of instruments, headphones, microphones, or other electronic musical devices. A personal music player docking station  826  and connector  828  enables rehearsal system  800  to interface with a personal music player, such as an iPod® or an mp3 player, enabling recording, playback of backing tracks, and other communication with an operating system of the personal music player. 
     Referring again to  FIG. 2A , a further feature of the rehearsal system  10  is a recording output listening switch  94  that allows a musician to audit the output of a channel, such as the channel used for recording. Using the recording output listening switch  94 , the musician can quickly switch from listening to the mix in his or her channel to listening to the mix in the channel used for recording. For instance, if  FIG. 2A  shows channel  12 , then recording output listening switch  94  allows the musician using channel  12  to listen to the output of, e.g., channel  16 . The recording output listening switch  94  is positioned on or near at least one of channels  12 ,  14 ,  16 ,  18 , or  20  of rehearsal system  10 . 
     Referring to  FIG. 9 , in one embodiment, a rehearsal system  900  includes a room simulation module  902  that simulates a ‘virtual room;’ that is, the room simulation module generates the sound effects associated with playing music in a particular location. In one example, the room simulation module allows musicians to change the virtual room from a small room to a large room. In another example, the room simulation module allows musicians to select an audio response copy of a famous performance space, such as Abbey Road Studios in London or the stage at Buddy Guy&#39;s Legends club in Chicago. The room simulation module  902  generates sound effects of a particular room performance space via a digital signal processor  904  and a control mechanism  906 , such as a knob or a touch screen LCD. The digital signal processor is preprogrammed with sound parameters of various types of rooms and performance spaces, such as how sound bounces around the room or performance space. To generate an output sound associated with playing music in a particular location, room simulation module  902  applies sound effects to signals in rehearsal system  900  based on the preprogrammed sound parameters. In one embodiment, a user of rehearsal system  900  creates a virtual room using a computer  908  and sends the virtual room to room simulation module  902  via a connector  910 . Room simulation module  902  determines sound parameters of the virtual room and generates sound effects associated with playing music in that virtual room. In this embodiment, it is possible to generate sound effects that are not possible in the physical world. 
     In another embodiment, using audio feedback and data logging, the rehearsal system provides user feedback to musicians using the rehearsal system, for instance to help the musicians improve their playing. Algorithms track, log, and report to the musicians the degree of coupling of the musicians or the consistency in beats per minute of a drummer. In one example, in response to a performance that satisfies a selected threshold of consistency, audio feedback is provided in the form of a tone meaning “good” or the sound of applause from an audience. 
     It is to be understood that the foregoing description is intended to illustrate and not to limit the scope of the invention, which is defined by the scope of the appended claims. Other embodiments are within the scope of the following claims.