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Due to recording mastering and manufacturing limitations, both high and low frequencies were removed from the first recorded signals by various formulae. With low frequencies, the stylus must swing a long way from side to side, requiring the groove to be wide, taking up more space and limiting the playing time of the record. At high frequencies, hiss, pops, and ticks are significant. These problems can be reduced by using equalization to an agreed standard. During recording the amplitude of low frequencies is reduced, thus reducing the groove width required, and the amplitude at high frequencies is increased. The playback equipment boosts bass and cuts treble so as to restore the tonal balance in the original signal; this also reduces the high frequency noise. Thus more music will fit on the record, and noise is reduced.

What is done during recordings to help reduce unwanted sounds?
Answer: amplitude of low frequencies is reduced
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The period between 1815 and 1871 saw a large number of revolutionary attempts and independence wars. Balkan nations began to regain independence from the Ottoman Empire. Italy unified into a nation state. The capture of Rome in 1870 ended the Papal temporal power. Rivalry in a scramble for empires spread in what is known as The Age of Empire.

What phrase is used to describe the period marked by competition for extant lands?
Answer: The Age of Empire
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In March 2013, Governor Rick Snyder declared a financial emergency in the city, stating that the city has a $327 million budget deficit and faces more than $14 billion in long-term debt. It has been making ends meet on a month-to-month basis with the help of bond money held in a state escrow account and has instituted mandatory unpaid days off for many city workers. Those troubles, along with underfunded city services, such as police and fire departments, and ineffective turnaround plans from Bing and the City Council led the state of Michigan to appoint an emergency manager for Detroit on March 14, 2013. On June 14, 2013 Detroit defaulted on $2.5 billion of debt by withholding $39.7 million in interest payments, while Emergency Manager Kevyn Orr met with bondholders and other creditors in an attempt to restructure the city's $18.5 billion debt and avoid bankruptcy. On July 18, 2013, the City of Detroit filed for Chapter 9 bankruptcy protection. It was declared bankrupt by U.S. judge Stephen Rhodes on December 3, with its $18.5 billion debt he said in accepting the city's contention that it is broke and that negotiations with its thousands of creditors were infeasible.

When did Detroit file for bankruptcy?
Answer:
July 18, 2013