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kamkarot

is a 5.2 surround system better than a 5.2?

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Crossed over properly you cannot tell what direction bass is coming from. Higher bass/midbass frequencies are directional but subwoofers in a home theater setting should not be playing much over 60 Hz.

Just because you filter the signal to the speaker won't defy physics. Sound comes from a source that creates it. an easy way to test this is to stand infront of a sub facing it, then turn around 180 degrees, its not going to still sound as if it is coming from infront of you as it did when you were facing it. This is were time alignment comes in. If you delay sounds so that all the waves meet at a point at the same time and you stand facing that point the sound is supposed to sound as it is coming from that point. When it is said that bass or subwoofers are non directional is a misconception as it is still directional. What people mean to say is that because of the wavelength of the frequencies that a subwoofer reproduces, it matter less were you put the subwoofer and still be able to hear the sound. It's still directional and comes from the direction it was produced as does all sounds.

Ah. Still, I'd run a mono subwoofer output to them to minimize distortion and maximize volume.

having more then 1 sub would infact add volume not lower it as when you add more subs you move more air, making more spl and therfor more volume. I think you might be confusing distortion with destructive interference, like I said before as long as you have enough room between them you shouldn't notice any of this and, if you did you can use the time alignment on your reciever to fix this, or you can move the placement of the speakers to correct this.

Edited by Mikesnow

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One subwoofer equivalent to the cost of two is likely to be more caapable if you choose the right components.

This is also subject to box size and power effects.

IE two 8 inch higher quality drivers and cabinets may cost less and be a more suitable size and power requirement than one twelve inch sub. Or not.

 

Klipsh Kornerhorns used a large folded horn design that included use of a room corner. Low power, excellent sound, expesive as hell now. [design dates to 1930s? mono systems]

Voice of the Theater, if I remember right was a large (stage size) efficent "build it yourself" speaker, um 15 inch woofer with two horns. [1970s]

 

At present small is good, but quality small costs extra in parts, design, and power.

 

That said many reasonable (for the time, 1980s) box speakers had very good base. [ADS LS 780? maybe?]

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One subwoofer equivalent to the cost of two is likely to be more caapable if you choose the right components.

This is also subject to box size and power effects.

IE two 8 inch higher quality drivers and cabinets may cost less and be a more suitable size and power requirement than one twelve inch sub. Or not.

 

Klipsh Kornerhorns used a large folded horn design that included use of a room corner. Low power, excellent sound, expesive as hell now. [design dates to 1930s? mono systems]

Voice of the Theater, if I remember right was a large (stage size) efficent "build it yourself" speaker, um 15 inch woofer with two horns. [1970s]

 

At present small is good, but quality small costs extra in parts, design, and power.

 

That said many reasonable (for the time, 1980s) box speakers had very good base. [ADS LS 780? maybe?]

 

Your right, as time goes by researches find more efficent ways to reproduce sounds, in the example of subs you can use a single 8" driver in a typical enclosure and it will making decent bass. Now if you cover that same 8" speaker enclosure with another encloser that has say 2 10" diaphrams, you will be moving as much air and creating as much air pressure as an 15" subwoofer would alone. It's pretty amazing the things they are developing these days, with sound it's pretty amazing imho.

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Mike why do you say designs now? I find that its older designs that are really just being largely recycled now. Not to mention there are things like the Voice of the Theater and JBL bass scoops and a whole variety of folded horn speakers that are very highly sought after even in their damages or deteriated vintage states.

 

Back to subs though, the output I'd meant to be non directional and true if you have it crossed reletively high to make up for poor mid end then you'll hear its direction clearly. There are also benifits to multiple subwoofers in smoothing out bass response and helping to remove room nulls.

 

Here is some good reading

 

http://www.audioholics.com/tweaks/get-good-bass/two-subs

 

 

http://www.audioholics.com/tweaks/get-good-bass/multiple-subwoofer-setup-calibration-1

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Mike why do you say designs now? I find that its older designs that are really just being largely recycled now. Not to mention there are things like the Voice of the Theater and JBL bass scoops and a whole variety of folded horn speakers that are very highly sought after even in their damages or deteriated vintage states.

When I refered to designs, I was talking about design of a system for a specific room. You can take the same equipment from one room to the next and you will get different sound. So designing a system for your room is important, the most important thing I would say.

Back to subs though, the output I'd meant to be non directional and true if you have it crossed reletively high to make up for poor mid end then you'll hear its direction clearly. There are also benifits to multiple subwoofers in smoothing out bass response and helping to remove room nulls.

 

Here is some good reading

 

http://www.audioholics.com/tweaks/get-good-bass/two-subs

 

 

http://www.audioholics.com/tweaks/get-good-bass/multiple-subwoofer-setup-calibration-1

all sounds are directional. think of your room and now think if you replaced the air with water. If you drop a pebble in a area of the room do the waves come from everywere instantaiuosly or do they come from the point the pebble dropped in? In good audio desgin the goal is to make the sound appear to come from the areas your content wants it too, but not so distinguishable that you can tell it's coming from a speaker. in the link you provided with the 4 subs and or 2 subs if they are getting the same signal you can increase the odds af making the sound seem non directional by having the bass waves from both subs reaching the listening position at the same time, in which then it would be hard for a human ear to determine the direction of the bass if this was your design purpose, however if the listener is sitting in any direction other then the 1 single point in the space he will notice a direction of sound. It all depends on your content, if your watching movies you want the sounds to come from were they are supposed to, if it's music like watching a concert on the tv you want it to sound as though its coming from up on stage. In a car for instance you want to try to make the sound like its all coming from the windshield.

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Just because you filter the signal to the speaker won't defy physics. Sound comes from a source that creates it. an easy way to test this is to stand infront of a sub facing it, then turn around 180 degrees, its not going to still sound as if it is coming from infront of you as it did when you were facing it. This is were time alignment comes in. If you delay sounds so that all the waves meet at a point at the same time and you stand facing that point the sound is supposed to sound as it is coming from that point. When it is said that bass or subwoofers are non directional is a misconception as it is still directional. What people mean to say is that because of the wavelength of the frequencies that a subwoofer reproduces, it matter less were you put the subwoofer and still be able to hear the sound. It's still directional and comes from the direction it was produced as does all sounds.

Bass is omnidirectional for the most part. Sure, standing right in front of a subwoofer will give you locational information. You don't sit right next to your subs do you (I sure hope not)? Properly set up you should not be able to determine whether the bass is coming from any specific direction.

 

having more then 1 sub would infact add volume not lower it as when you add more subs you move more air, making more spl and therfor more volume. I think you might be confusing distortion with destructive interference, like I said before as long as you have enough room between them you shouldn't notice any of this and, if you did you can use the time alignment on your reciever to fix this, or you can move the placement of the speakers to correct this.

I didn't say one sub, I said mono. IE: drive both of your subwoofers with the same signal. Running them in stereo is useless (and counterproductive) unless you have them crossed over high enough for you to pick out their location.

 

Your right, as time goes by researches find more efficent ways to reproduce sounds, in the example of subs you can use a single 8" driver in a typical enclosure and it will making decent bass. Now if you cover that same 8" speaker enclosure with another encloser that has say 2 10" diaphrams, you will be moving as much air and creating as much air pressure as an 15" subwoofer would alone. It's pretty amazing the things they are developing these days, with sound it's pretty amazing imho.

That's not really how it works. A single 8" driver can only move as much air as that 8" driver can sweep (so, within reason, the cone area * the xmax of the driver). The diaphragms (passive radiators) just take the place of ports (for a 4th order box anyway) and are used to take advantage of the rear wave from the driver to enforce the front wave at certain frequencies. Ports are always more efficient but they're a lot harder to fit in small designs.

 

You can get fancy and do 6th order and 8th order boxes (bandpass) but group delay becomes an issue. Efficiency, however, can absolutely skyrocket. I built an 8th order box a few years back that did 140 dB at 25 Hz with only ~300 watts of clean power in a fairly large car. It was massive and sounded like a wet fart on anything complicated...but it would have made an excellent home theater subwoofer where impact is all that matters. :lol:

 

all sounds are directional. think of your room and now think if you replaced the air with water. If you drop a pebble in a area of the room do the waves come from everywere instantaiuosly or do they come from the point the pebble dropped in? In good audio desgin the goal is to make the sound appear to come from the areas your content wants it too, but not so distinguishable that you can tell it's coming from a speaker. in the link you provided with the 4 subs and or 2 subs if they are getting the same signal you can increase the odds af making the sound seem non directional by having the bass waves from both subs reaching the listening position at the same time, in which then it would be hard for a human ear to determine the direction of the bass if this was your design purpose, however if the listener is sitting in any direction other then the 1 single point in the space he will notice a direction of sound. It all depends on your content, if your watching movies you want the sounds to come from were they are supposed to, if it's music like watching a concert on the tv you want it to sound as though its coming from up on stage. In a car for instance you want to try to make the sound like its all coming from the windshield.

See now that's just not true. It's not very difficult to set up a system where the bass sounds completely non-directional.

 

A proper front sound stage in a car will fool your ears into thinking ALL sound comes from the front of the car. I had my old car set up like this and while it took more effort than a home theater setup would (due to space constraints) it still wasn't difficult by any means. It just took 8" midbass drivers in the doors with a couple hundred watts each to achieve.

 

Back to subs though, the output I'd meant to be non directional and true if you have it crossed reletively high to make up for poor mid end then you'll hear its direction clearly. There are also benifits to multiple subwoofers in smoothing out bass response and helping to remove room nulls.

 

Here is some good reading

 

http://www.audioholics.com/tweaks/get-good-bass/two-subs

 

 

http://www.audioholics.com/tweaks/get-good-bass/multiple-subwoofer-setup-calibration-1

This. Just because you hear a bunch of buzzwords in an ad for high-end speakers doesn't make what they say true (I'd argue that anything you read in an ad, especially an audio one, is probably worth forgetting instantly :lol:).

 

I guarantee not a single person here on OCC could tell whether or not I even have a subwoofer in my setup if I blindfolded them and they hadn't seen it before. It's not super high-end or anything but it does play clean, flat (with the exception of a bass shelf), and relatively distortion free at ear-bleeding output levels.

 

 

 

/rant over :lol:

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Bass is omnidirectional for the most part.

Exactly, it comes from the source, radiating outwards, thats my point. It don't move on one side of the room and magically make sound come from the otherside of the room.

 

I didn't say one sub, I said mono. IE: drive both of your subwoofers with the same signal. Running them in stereo is useless (and counterproductive) unless you have them crossed over high enough for you to pick out their location.

My bad... If you are listening to stero music then yes you will have greater output from both speakers recieving the same signal. in entertianment content were something else is tring to be acheived then having the extra discrete channels would be better.

 

That's not really how it works. A single 8" driver can only move as much air as that 8" driver can sweep (so, within reason, the cone area * the xmax of the driver). The diaphragms (passive radiators) just take the place of ports (for a 4th order box anyway) and are used to take advantage of the rear wave from the driver to enforce the front wave at certain frequencies. Ports are always more efficient but they're a lot harder to fit in small designs.

 

You can get fancy and do 6th order and 8th order boxes (bandpass) but group delay becomes an issue. Efficiency, however, can absolutely skyrocket. I built an 8th order box a few years back that did 140 dB at 25 Hz with only ~300 watts of clean power in a fairly large car. It was massive and sounded like a wet fart on anything complicated...but it would have made an excellent home theater subwoofer where impact is all that matters. :lol:

 

Actually thats exactly how it works, other wise everyone would just use a standard acustic suspension enclosures, and that was my point. People find ways to make speaker eclosures more efficent giving you the same amount of output that a larger speaker can but with less space and less power. Transsmission line enclosures or as stoner said folded horn designs are very efficent and why they are a sought after design to use.

 

I guarantee not a single person here on OCC could tell whether or not I even have a subwoofer in my setup if I blindfolded them and they hadn't seen it before. It's not super high-end or anything but it does play clean, flat (with the exception of a bass shelf), and relatively distortion free at ear-bleeding output levels.

I think I could tell, but I have never in my life head a system that I couldn't tell were it was coming from, even the old bose studios which were pretty good, I could still tell. :) But if you made my ears bleed I prolly would fail...fail to ever even hear again.... :D I would not want that.

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what subwoofer do you own Waco? also I would take on that challenge, I could most likely tell just because of extra bass. Being clean differently makes it's hard to hear in a blind test but I'm confident enough. I think the point you where trying to make was something I tried to say also. it's better to feel it than hear it. it's hard to explain but when you feel the push from the airwaves and you don't know where it came from, the movie is just that much better.

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Exactly, it comes from the source, radiating outwards, thats my point. It don't move on one side of the room and magically make sound come from the otherside of the room.

Omnidirectional means there is no directionality. :P

 

My bad... If you are listening to stero music then yes you will have greater output from both speakers recieving the same signal. in entertianment content were something else is tring to be acheived then having the extra discrete channels would be better.

Subwoofers shouldn't be directional though. Woofers, yes, but not subwoofers crossed over properly.

 

 

 

Actually thats exactly how it works, other wise everyone would just use a standard acustic suspension enclosures, and that was my point. People find ways to make speaker eclosures more efficent giving you the same amount of output that a larger speaker can but with less space and less power. Transsmission line enclosures or as stoner said folded horn designs are very efficent and why they are a sought after design to use.

Not really. There's always a tradeoff. Efficiency, extension, enclosure size. You can pick two. Hoffman's iron law (I think that's the name anyway).

 

 

I think I could tell, but I have never in my life head a system that I couldn't tell were it was coming from, even the old bose studios which were pretty good, I could still tell. :) But if you made my ears bleed I prolly would fail...fail to ever even hear again.... :D I would not want that.

Probably not. I have 12" drivers in my mains (ported to 40 Hz) that blend seamlessly with the subwoofer. :lol: If I didn't have it on you'd still probably think it was on just because the output it can do without it is still pretty massive. :teehee:

 

what subwoofer do you own Waco? also I would take on that challenge, I could most likely tell just because of extra bass. Being clean differently makes it's hard to hear in a blind test but I'm confident enough. I think the point you where trying to make was something I tried to say also. it's better to feel it than hear it. it's hard to explain but when you feel the push from the airwaves and you don't know where it came from, the movie is just that much better.

Dual 12" drivers in 8 cubic feet ported to ~20 Hz. You can tell an obvious difference if it's on versus if it's off (just because of the subsonic output) but my mains are large enough that most people think it's on even when it isn't. :lol:

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Can someone find me a movie with a 5.2 or 7.2 soundtrack and then find me a DVD/bluray player with 7.2 audio out and then the reciever with 7.2 input. If you find all that I will believe that the subwoofer output in a home theater is meant to be directional.'

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Can someone find me a movie with a 5.2 or 7.2 soundtrack and then find me a DVD/bluray player with 7.2 audio out and then the reciever with 7.2 input. If you find all that I will believe that the subwoofer output in a home theater is meant to be directional.'

:lol:

 

Have fun with that. Bass is meant to be omnidirectional and no matter how many subs you have you're going to get mono bass. If you set things up properly it won't sound any different than a BIG system without a subwoofer at all.

 

I'd bet that most receivers with a "stereo" subwoofer output just downmix it from the left/right stereo channels. In that case you're just using your subs to reinforce the lacking low-end on your mains. :P

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:lol:

 

Have fun with that. Bass is meant to be omnidirectional and no matter how many subs you have you're going to get mono bass. If you set things up properly it won't sound any different than a BIG system without a subwoofer at all.

 

I'd bet that most receivers with a "stereo" subwoofer output just downmix it from the left/right stereo channels. In that case you're just using your subs to reinforce the lacking low-end on your mains. :P

Well done on making clear the obvious point I was making :P

 

I am making myself some fostech fullrange horns for my stereo. Two 8 inch drivers to handle everything from the real low end to the the highest highs may consider some bullet tweeters later on though.

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