Question

In: Physics

Two small speakers A and B are driven in step at 720Hz by the same audio oscillator

Two small speakers A and B are driven in step at 720Hz by the same audio oscillator. These speakers both start out 4.50m from the listener, but speaker Ais slowly moved away.

Part A:
At what distance d will the sound from the speakers first produce destructive interference at the location of the listener?

Part B:
If A keeps moving, at what distance d will the speakers next produce destructive interference at the listener?

Part C:
After A starts moving away, at what distance will the speakers first produce constructive interference at the listener?

Solutions

Expert Solution


In air, the wavelength of 725Hz is about 0.47m.
So speaker A is 180° out of phase at 4.5+0.235= 4.735m and again at 4.5+0.47+0.235=5.205m.
Speaker A is in phase at 4.5+0.47=4.97m

However those are the simple answers. As the speaker moves away, it gets quieter and anything between 90° and 270° is "destructive" wrt the vector at B, or120° to 240° wrt the total absolute value < B alone, so
1. the FIRST destructive interference is at >90° or >120°, not at 180°
2. the maximum destructive interference is slightly before 180° because the distance is also reducing the absolute value.


Related Solutions

Two small speakers A and B are driven in step at 730 Hz by the same...
Two small speakers A and B are driven in step at 730 Hz by the same audio oscillator. These speakers both start out 4.50 mfrom the listener, but speaker A is slowly moved away. (See the figure (Figure 1) ). The speed of sound in air is 344 m/s . A. At what distance d will the sound from the speakers first produce destructive interference at the location of the listener? B. If A keeps moving, at what distance d...
Two speakers 5 m apart, are driven in phase by the same amplifier, at a frequency...
Two speakers 5 m apart, are driven in phase by the same amplifier, at a frequency of 775 Hz. The speed of sound is 340 m/s. An observer starts 5m away from one of the speakers at a point along the perpendicular to the line connecting the two speakers, and moves away from the speakers along that line. a) How much distance separates the second and the third interference minima they hear? b) Do you expect the intensity at the...
Two point source three meter apart are driven by the same oscillator at a frequency of...
Two point source three meter apart are driven by the same oscillator at a frequency of 800 hz. The sources emit energy in the form of spherical waves. An observer initially hears a maximum at a distance 10 m along the perpendicular bisector of the line joining the two sources. What distance (in m) must observer move along a line parallel to the line joining the two sources before reaching a minimum intensity? (Assume the speed of sound is 343...
The two speakers are placed 37.2 cm apart. A single oscillator makes the speakers vibrate in...
The two speakers are placed 37.2 cm apart. A single oscillator makes the speakers vibrate in phase at a frequency of 2.02 kHz. At what angles, measured from the perpendicular bisector of the line joining the speakers, would a distant observer hear maximum sound intensity? Minimum sound intensity? (Take the speed of sound to be 340 m/s.) maximum intensities: (List smallest angle first.) θ1max =  ° θ2max =  ° θ3max =  ° minimum intensities: (List smallest angle first.) θ1min =  ° θ2min =  °
Bulldog, Inc. is a Texas-based audio equipment manufacturer. It produces two kinds of audio speakers. The...
Bulldog, Inc. is a Texas-based audio equipment manufacturer. It produces two kinds of audio speakers. The first kind is a bookshelf speaker, called BSS. The other kind is a floor speaker, called FLS. Both BSS and FLS use cherry wood for speaker body structure. Each BSS uses 2 sheets of cherry wood and each FLS uses 5 sheets of cherry wood for production. Each month Bulldog, Inc. has 600 sheets of cherry wood available for production. According to its metropolitan...
Two speakers, A and B, are at the same point on an x-axis and each emits...
Two speakers, A and B, are at the same point on an x-axis and each emits sound with a wavelength of 0.25 m. Speaker B's phase constant is 260 degrees larger than speaker A's phase constant and each produces an amplitude of 10 Pa. What amplitude occurs along the x-axis in front of these speakers (Pa)? b. What is the minimum distance you can move speaker A to achieve constructive interference along the x-axis? Give a positive answer regardless of...
Harmony Audio Company manufactures two models of speakers, DL and XL. Based on the following production...
Harmony Audio Company manufactures two models of speakers, DL and XL. Based on the following production and sales data for September 2016, prepare (a) a sales budget and (b) a production budget. DL XL Estimated inventory (units), September 1 253 70 Desired inventory (units), September 30 291 61 Expected sales volume (units): East Region 3,500 3,900 West Region 4,800 4,200 Unit sales price $100 $225 a. Prepare a sales budget. Harmony Audio Company Sales Budget For the Month Ending September...
Sales and Production Budgets Ultimate Audio Company manufactures two models of speakers, U500 and S1000. Based...
Sales and Production Budgets Ultimate Audio Company manufactures two models of speakers, U500 and S1000. Based on the following production and sales data for June. U500 S1000 Estimated inventory (units), June 1 284      83 Desired inventory (units), June 30 327 72 Expected sales volume (units): Northeast Region 3,800 3,350 Southwest Region 5,550 6,250 Unit sales price $110 $215 a. Prepare a sales budget. Enter all amounts as positive numbers. ULTIMATE AUDIO COMPANY Sales Budget For the Month Ending June...
Vintage Audio Inc. manufactures audio speakers. Each speaker requires $108 per unit of direct materials. The...
Vintage Audio Inc. manufactures audio speakers. Each speaker requires $108 per unit of direct materials. The speaker manufacturing assembly cell includes the following estimated costs for the period: Speaker assembly cell, estimated costs:    Labor $34,100    Depreciation 4,570    Supplies 1,660    Power 1,250      Total cell costs for the period $41,580 The operating plan calls for 165 operating hours for the period. Each speaker requires 20 minutes of cell process time. The unit selling price for each speaker is $292. During the period,...
Vintage Audio Inc. manufactures audio speakers. Each speaker requires $111 per unit of direct materials. The...
Vintage Audio Inc. manufactures audio speakers. Each speaker requires $111 per unit of direct materials. The speaker manufacturing assembly cell includes the following estimated costs for the period: Speaker assembly cell, estimated costs: Labor $51,360 Depreciation 6,890 Supplies 2,510 Power 1,880 Total cell costs for the period $62,640 The operating plan calls for 180 operating hours for the period. Each speaker requires 15 minutes of cell process time. The unit selling price for each speaker is $301. During the period,...
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT