|
|
![]() |
||||||||||||||||||||
|
Best Blu-ray Movie Deals
|
Best Blu-ray Movie Deals, See All the Deals » |
Top deals |
New deals
![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() |
![]() $17.96 5 hrs ago
| ![]() $19.99 1 day ago
| ![]() $19.99 1 day ago
| ![]() $19.99 1 day ago
| ![]() $12.49 5 hrs ago
| ![]() $26.36 | ![]() $19.99 18 hrs ago
| ![]() $25.99 5 hrs ago
| ![]() $23.99 1 day ago
| ![]() $19.99 1 day ago
| ![]() $24.49 | ![]() $33.49 |
|
![]() |
|
Thread Tools | Display Modes |
|
![]() |
#1 |
Blu-ray Champion
|
![]()
It is highly recommended that you also read https://forum.blu-ray.com/speakers/1...s-part-ii.html.
OFF-AXIS RESPONSE OF SOUND WAVES The following diagram demonstrates that high frequency sound waves have a narrower off-axis response and the low frequency sound waves have a much wider off-axis response. That is why when you stand to one side or behind a subwoofer, you still hear bass frequencies like you were in front, but will not hear midrange or higher frequencies. It is said that the higher frequencies sound waves behave like headlights or flashlights and low frequency sound waves behave like ripples of water waves in a pool. This is why tweeters are shaped like domes. A curved diaphragm pushes high frequency sound waves in a way that aides dispersion. INTERFERENCE OF SOUND WAVES Interference usually refers to the interaction of waves with each other, When similar independent waves are combined, the result can be either constructive or destructive interference, depending on whether the waves are in phase or out of phase. This interference occurs when the waves have the same or nearly the same frequency. Constructive interference will enhance sound. Destructive interference will weaken sound. If two identical waves are 180 degrees out of phase, they will cancel out. Whether the interference is constructive or destructive, the individual waves continue to exist separately. The interference itself is merely the effect of the waves together at one point in space. The animation in the following demonstrates two waves traveling in the same direction. The phase difference between the two waves varies with time so that we see constructive interference when maximum points are aligned (peak) and destructive interference when minimum and maximum points are aligned (null). The direction that speakers radiate their sound depends on how the drivers are lined up in the enclosure, and also whether there are drivers or ports on the back of the speaker. If all the speakers are on the front, this would be called Monopole. If there are speakers on the front and back, and they are in phase (both speaker cones moving away from the magnet), this is called Bipolar, whereas if the cones are out of phase (one cone moving in towards the magnet, while the other cone is moving outwards, away from the magnet), the speaker design is called Dipolar. Monopole Speaker Monopole speakers consist of a driver or a group of drivers in the speaker cabinet all firing on the same plane in the same direction. A conventional sealed box speaker pushes a small cone back and forth against the air and creates sound. You can see that for a box speaker most of the sound goes one direction (monopole) and that the box construction plays an important part of how this makes sound. Bipolar Speaker Another way to create sound waves is by a bipolar arrangement, where the front and back speakers work against each other (in phase). Bipolar speakers are made by mounting in-phase monopoles on opposite sides of a box as a way of creating omnidirectional radiation patterns. Here is what they look like Dipolar Speaker Dipolar speaker arrangement is similar to bipolar. However, the front and the back speakers work in the same direction (out of phase). This can be useful in reducing the stimulation of resonant room modes at low frequencies. It also results in high frequencies being reflected from the rear wall, which can create more diffuse reverberation, though in theory it could reduce stereo localization. Here is how they look DISPERSION PATTERNS OF THE MAIN DIAPHRAGMS Direct Radiating (Monopole) In a direct radiating monopole, a diaphragm compresses the air in front of it and pushes the wave outward. As the wave expands, its energy is distributed, resulting in lower pressure and a reduction in its loudness. This shown in the following diagram (please be patient, the file size of this simulation is 5.6MB and takes a long time to load): Bipolar Speaker Dispersion Pattern For two sound sources at same frequency, amplitude, and phase, there will be points in space where the overall sound level is high (constructive interference) and other places where the sound level is approximately zero (destructive interference). The constructive interference occurs as their off-axis response (mostly lower frequency waves) reinforce each other. That is why bipolar speakers are known for their strong dispersion. Dipolar Speaker Dispersion Pattern The radiation pattern of a dipole is demonstrated in the following diagram. The left waves are equal and opposite to the waves on the right. Because they are firing out of phase, they cancel each other where these waves are superimposed off-axis (top and bottom, mostly lower frequency waves). This is called destructive interference and creates a figure 8 pattern. Dipole speakers are known to have weaker bass response. Comparison of the Dispersion Patterns In the above diagram, note that the bipole field shows a larger off-axis response (the middle part of the center diagram) compared to the monopole. This is because the drivers in the front and rear are in-phase, which constructively reinforce the sound waves. Dipole speaker arrangement, however, exhibits a smaller off-axis response (middle part of the diagram on the right) compared to the monopole. This is because a dipole arrangement has out-of-phase drivers which behave in a destructive manner and cancel the sound waves with the same frequency. REFLECTION FROM THE BOUNDARIES Reflection from the Back Wall for Bipolar Speaker The following diagrams demonstrate two waves when the speaker drivers are operating in phase. The reflection form the rear driver can interfere with the wave coming from the front driver and create constructive reinforcement (called lobing, light areas) or destructive interference (called null, dark areas). Reflections from the Back Wall for Dipolar Speaker When the back-wave starts off from the rear of the speaker and reflects off the back-wall and travels back to the speaker where it recombines with the new wave just being started from the front driver. Because of timing difference, at some frequencies the two waves destroy each other and at other times they reinforce one another. This effect is called comb filtering A comb filter adds a delayed version of a signal to itself, causing constructive and destructive interference. Some dipolar users treat the back-wall with absorbent material that absorbs all frequencies except the long bass frequencies. That is one way to prevent comb filtering. Another way is to turn the dipolar speakers inward so that they are not parallel to the rear wall. FRONT SPEAKERS SETUP For front speakers, put the speakers at least 2-3 feet (approx. 1 meter) away from the front and side walls.
![]()
DIPOLAR & BIPOLAR SURROUND SPEAKERS SETUP Dipole speakers are designed to have a null area in front of them and the listener is intended to sit within that null for the proper ambient effect. When you sit in the null area, you will get a diffuse sound that is more appropriate for surround speakers. Bipole speakers, on the other hand, have no null area, and are much more flexible in their placement. They can be installed on the side walls or on the back wall with excellent results. Normally, surround speakers are placed at or above ear level. However, for movies, installing them 2ft to 3 ft above ear level is preferred. In a 5.1 setup, you have three options for installing bipolar speakers:
In a 5.1 setup, dipolar speakers are installed on the side walls or hung from the ceiling on the same line as the listener (the null area faces the listener). In a 7.1 setup, dipolar speakers can be used. However, care must be taken to position them properly (see the section below). ![]() ![]() ![]() ![]() ![]() All diagrams are created by Big Daddy In case you have a wall on one side and the other side is open, you can attach one surround speaker to the wall and attach the other one to the ceilining with a chain or with a bracket. Alternatively, you can put that speaker on a tall stand. Make sure the heights and distances are the same. http://nsmt-loudspeakers.com/nsm-bro...ers-manual.pdf ![]() Dipolar Surround Speakers in a 7.1 Setup Dipole surround speakers are typically labeled Left and Right so that, when you place them on the sides, the in-phase drivers are pointing towards the front of the room. This allows them to be in phase with your front speakers and avoid cancellation problems that can occur when out of phase drivers are facing each other. If, in a 7.x setup, you decide to use another pair of dipole surround speakers in the rear, you will have to place the left speaker on the right side and the right speaker on the left side as in the diagram below. This is to avoid cancellation problem when the speakers are out of phase. If you decide to use direct radiating speakers or bipole speakers in the rear, you will not need any special consideration. ![]() For dipole speakers, if there are arrows on the speakers they should face the front of the room for the side speakers, and toward the center of the wall for the rear speakers. DIRECT-RADIATING MONOPOLE SURROUND SPEAKERS SETUP When you use direct-radiating monopole speakers as rear or side surround speakers, they can may be placed on the side or behind the listeners. When used on the sides close to the listeners, make sure they are not ahead of the listening position and they are not directly aimed at their heads (Fig. A). If positioned several feet behind the listening position, experiment with speaker aiming (Fig. B). ![]() Different Options for Direct-Radiating Monopole Surround Speakers KEY CONSIDERATION WHEN CHOOSING DIRECT OR BIPOLE/DIPOLE SURROUND SPEAKERS Arguments will vary from person to person, based upon the preference of the individual. Movies:
On the other hand, there are some listeners who do not like this kind of music reproduction, and prefer to have a very specific, almost pinpoint, sense of image position. Many recording engineers prefer this because they need to be able to hear, very precisely, the results of their manipulations. As a result, recording studios are often acoustically rather dead, and the loudspeakers are directional and identical. They use identical speakers so that they are perfectly timbre matched so that the sound is not affected by the differences between the speakers. However, these same people usually prefer the more spacious sound field at home. SUMMARY Advantages of Bipole Speakers
ADDITIONAL INFORMATION AND REFRENCES http://www.ecoustics.com/Home/Home_A...les/alpha.html http://www.educypedia.be/electronics/loudspeakers.htm http://www.headwize.com/tech/elemnts_tech.htm http://en.wikipedia.org/wiki/Destruc...e_interference http://www.kettering.edu/~drussell/Demos.html http://www.integracoustics.com/MUG/MUG/articles/planar/ http://en.wikipedia.org/wiki/Dipole_loudspeaker http://www.djsociety.org/Speaker_1.htm http://www.integracoustics.com/MUG/M...icles/sources/ http://www.polkaudio.com/downloads/hthandbook.pdf http://www.bobgolds.com/DipoleSurrounds/home.htm http://media-server.amazon.com/media...L000035963.pdf (P. 15) http://www.bwspeakers.com/downloadfi...DS7_manual.pdf (P.2, Fig. 5) http://66.218.69.11/search/cache?ei=...icp=1&.intl=us http://www.harman.com/wp/pdf/HowManyChannels.pdf http://www.approvedarticles.com/Arti...ed-To-Know/495 http://www.harman.com/wp/pdf/Loudspe...ndRoomsPt1.pdf http://www.harman.com/wp/pdf/Loudspe...ndRoomsPt2.pdf http://www.harman.com/wp/pdf/Loudspe...ndRoomsPt3.pdf http://www.electronichouse.com/artic...dex.php/?cr=on http://www.audioholics.com/news/on-l...sound-standard http://www.aesnashville.org/PDFs/Tec...tal%20FAQs.pdf http://www.hometheatershack.com/foru...ar-better.html http://www.diyaudio.com/forums/showt...?postid=445666 http://www.electronichouse.com/artic...rect_speakers/ http://www.buyingloudspeakers.com/Sp...0Enclosure.htm Last edited by Big Daddy; 04-21-2013 at 09:55 PM. |
![]() |
![]() |
#2 |
Blu-ray Champion
|
![]()
Check this thread for Alphabetical List of Bipolar and Dipolar Surround Speaker Manufacturers.
Last edited by Big Daddy; 04-05-2009 at 02:12 AM. |
![]() |
![]() |
#4 |
Banned
Aug 2008
|
![]()
Ah, but what about the "Omnipolar"?
|
![]() |
![]() |
#5 |
Blu-ray Champion
|
![]() |
![]() |
![]() |
#8 | |
Blu-ray Champion
|
![]() Quote:
|
|
![]() |
![]() |
#10 | |
Special Member
|
![]() Quote:
![]() My question is this. What if my rears aren't bookend "left" and "right" pairs? I have Energy RC-R's and side-by-side, they are exactly the same. The negative (-) terminal is on the same side on both speakers (the side with the dipole/bipole switch, see my gallery pics). It is therefore impossible to "mirror" them with the positive (+) terminal facing forward in a side wall mounting configuration without mounting one of them upside down. They are set to "Dipole" now. If both positive terminals can't face forward, is it better to set them to "Bipole"? |
|
![]() |
![]() |
#11 | |
Blu-ray Champion
|
![]() Quote:
1. If you set the surround speakers to Bipole, make sure you install them to the rear of the main seating position and higher than your head. You don't have to worry about anything else, except calibration of your entire system. 2. If you set the surround speakers to Dipole, make sure you install them approximately on the same line as the main listening position, facing you, and slightly above your head. I believe you misunderstood what I meant by Positive and Negative. It has nothing to do with + and - on the speaker terminals. I was referring to the direction of the movement of the midrange woofers. When you set your surround speakers to Bipole, the two midrange woofers will move out of phase with one another. This means that when one moves out (+), the other one moves in (-). Make sure the positive sides (woofer moving out) of your surrounds are facing your front speakers and the negative sides (woofer moving in) are facing the rear wall. This way, the front speakers will be in phase with your surround speakers in order to lessen the phase cancelletion problem of out-of-phase sound waves. |
|
![]() |
![]() |
#12 | |||
Special Member
|
![]()
7.1, but I use direct radiating speakers for surround backs.
Quote:
Quote:
Quote:
![]() |
|||
![]() |
![]() |
#13 |
Power Member
|
![]()
Big Daddy
I have Paradigms AdP-170's. My couch is right against the wall.I have them centered in the room with 3 feet in between them and 2 1/2 from ear level. I've always questioned if i had them placed right or even to the point of just buy powerful bookshelf's to replace them,what do you think.(Just trying to get it right ![]() http://reviews.cnet.com/separate-spe...-30112538.html Last edited by ozzman; 11-06-2008 at 10:53 PM. |
![]() |
![]() |
#14 | |
Blu-ray Champion
|
![]() Quote:
|
|
![]() |
![]() |
#16 |
Blu-ray Champion
|
![]() |
![]() |
![]() |
#17 |
Power Member
|
![]()
BigDaddy
as you well know my situation.I have to ask.I own a older pair of energy's.I could hang them off the back wall(Tilt them alittle) face the couch . Replace the Paradigms(ADP-170)till i get more room.Honestly what do you think Or should i leave the speakers were they are for now. Thanks http://vancouver.en.craigslist.ca/ele/883627308.html |
![]() |
![]() |
#18 | |
Blu-ray Champion
|
![]() Quote:
|
|
![]() |
![]() |
#20 | |||
Blu-ray Champion
|
![]() Quote:
http://ask.audyssey.com/entries/98040-speakers-for-dsx Quote:
Quote:
|
|||
![]() |
|
|
![]() |
![]() |
![]() |
||||
thread | Forum | Thread Starter | Replies | Last Post |
Bipolar and Dipolar Surround Speaker Manufacturers | Speakers | Big Daddy | 21 | 12-12-2022 06:50 PM |
Surround Speakers | Speakers | eric04m | 9 | 12-09-2009 03:41 PM |
surround speakers | Speakers | Opips2 | 6 | 02-15-2009 03:11 PM |
Thread Tools | |
Display Modes | |
|
|