Then a sound check is initiated to check the levels of the music, sound effects, or microphones to be used during the performance. Changes are made as necessary to correct volume, pitch, or feedback problems.
Lastly, for stage shows, the fly rigs or battens are tested for weight and accuracy of cueing with sound and lights. If there are moving set pieces, the crew will test their operation and mechanics (if they are automated) and practice their movement, flow, and position on and offstage.
There may be an extra step for particularly effect-intensive productions, such as film, TV, or Broadway-style stage shows, where the crew tests any special effects that require systems such as rain, fire, or explosions. When these effects are completed to the director's and production designer's satisfaction, the crew is ready to move onto the tech.
Often included in the tech are the final show props. These props differ from rehearsal props because they are not just placeholders, they are the props to be used in the actual production. This is so that a performer can become acquainted with the true prop before the actual performance so as not to look awkward when using it. It is also to test the durability of the final prop, as well as how the props will look under the final stage lighting.
Costumes are usually reserved for the dress rehearsals, but sometimes they are brought in to test the costumes against the final stage lighting as well, so as not to produce a conflict in color differentiation in the final product. Also, costume pieces that restrict movement or fit strangely such as shoes, hats, gloves and so on may be added either in their final form or (usually) in rehearsal form approximating size, shape, etc. to allow actors to get used to them in advance. Sometimes actors will get dressed in costume for the first time and come on stage so the production staff can see the costumes in their finished form for the first time under stage lighting. This is called a costume parade.
During the tech, all of the previous actions taken during the dry tech are repeated, so as to check lighting in concordance with the staged blocking and stage placement (for example, finding whether the performer is in the light hotspot or not, or how the followspot operates), check the levels on the performers' microphones (if used) and how well the performers can project if orating concurrently with sound or music, allow the performers to know when there are incoming flying rigs, allow performers to experience and become accustomed to the special effects that will occur so that it will not interfere with the actual performance and generally make sure the director and designers are happy with all aspects of the production that can be seen or heard. One very significant effect that is added in tech is blood. This allows actors to get used to them and the costume designer to see how the blood will affect the costumes.
Once completed as many times as the director feels comfortable, the tech will end. Any number of actions can usually be taken after a tech such as the running of problematic scenes or acts, another dry tech to work out problematic technical issues, or certain performers may be held to work with certain effects that the other performers aren't needed for. After all this is completed, the tech rehearsal is officially over, and the next rehearsal to be performed is the dress rehearsal, then final dress.
If the show is on tour, additional tech rehearsals may be held to cover issues that might arise from being in a different size/shape performance space. Issues might include: set size, timing, lighting angles and intesnsity, offstage storage, etc. Due to the fast paced nature of tours, often there is very little or no time for additional tech rehearsals.
Technical rehearsals may run in a different order than indicated above, or possibly include other production departments, such as sets, CGI effects, or even costumes.