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#81
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Subwoofer direction
I'll say it again, as I've said over and over. YOU, Tom Nousaine, keep
spouting that we are only offering "conjecture", and yet you have provided nothing more yourself. You are conjecturing as much as the next guy. You have posted no physical evidence of anything. You merely TYPE and expect everyone to believe you. Why is your conjecture any better than the next guys? We've already pointed out that we HAVE done tests in the past, hundreds (maybe thousands) of times, and we've seen others do the same, and it happens. Our word is the same as your word. NOBODY has provided any physical evidence to support either side, yet you expect everyone to believe your side merely because you are a relatively well known writer for a popular mobile electronics rag. But you and Eddie provide no data. It's just talk. Attempted verification of his 60-Hz point should be easy. I've done so twice in the past week. Thosands? I see noevidence of that. But even so; it's not a popularity contest. It's either true pr it isn't. And its easy to verify with a simple experiment. I guess you don't read any of the major audio forums, or deal with people in the real world of car audio every day then. I was in the business for 17+ years, and I heard this statement made at least once a week, quite often more. I've seen it happen, be it just by ear/feel/whatever, as well as at competitions where the only thing being played is subs, and only at 80hz and below. I've watched guys test their systems, get a low #, and immediately switch the box around (in their alloted time frame), and then hit it again and achieve a higher #. If it isn't happening, then I'd like to know why the mics and meters, and the people involved are seeing it happen. So you're saying that a loud burp at 75 Hz doesn't have higher frequency distortion and harmonic content? No, I am not saying that, but if you have ever been involved in a dB Drag event, you would know that they do not register anything above 100hz to begin with. If your peak is above 100hz, you are disqualified. There is filtering in place so that these frequencies are NOT a factor. Learn a little about the subject before you try to debunk it. But,no matter, we are talking here about whether 'aiming' your enclosure generally increases low frequency output. It's easy to show with simple experimentation that it doesn't. So you're saying that controlled experimental conditions don't reveal the truth. Great, tell that to scientists all over the world. Yes, I'm saying quite often the results are bull****. How many times have "scientists" told us that something was good for us, and six months later they tell us that it is NOT good for us. Scientific evidence is often disputed, and re-evaluated and found to be quite FALSE. Why not supply some experimental data so we can replicate this? That's what's so funny about this whole deal. As soon as I have the time, and energy to do it, I'll try to take care of it. I'll even remember to provide real PROOF of what is happening, not just mere conjecture like you keep providing. Anyone can SAY they did the tests and that their results were as they suspected, but most people that do these tests will actually take some photographs, and/or video tape to substantiate their claims. Your "word" is not good enough for me if my word is not good enough for you. lol I've provided 2 sets of experimental data in the past week. You and Eddie just continue to argue. Get busy. No, you've provided the same "conjecture" that you keep whining about. You PROVE it. I haven't seen any documented evidence from you or Eddie. Just conjecture. Same to you. |
#82
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Subwoofer direction
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#83
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Subwoofer direction
It would be nice if I didn't have to drive 45 miles to my old shop to use
their meter, but it's cheaper than buying one! Paul Vina "Fat *******" wrote in message ... Excellent. Thank you for the contradictory evidence to my (and the rest of the majority of those responding so far) theory, and findings. See, I am not afraid to see a differing opinion, or results, even if it supports Tom and his theory. I hope you meter it to get some other information on it. Hopefully it will spur others to do the same. "Paul Vina" wrote in message . net... I just wanted to chime in on this one. In my wife's car she's running an S12L5. I have it crossed over at about 65Hz. I played a 60Hz tone at a reasonable level and listened. Without making any adjustments, I opened the trunk, turned the box around and listened again and it sounded the same. Then I moved the box to the rear of the trunk (again no volume changes) and listened and again it was the same. No matter where I put it or which direction it faced it sounded the same. I'm not saying this was the most scientific test, but it satisfied my curiosity. I may get out an RTA and test it in a week or two and I'll post the results. Paul Vina |
#84
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Subwoofer direction
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#85
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Subwoofer direction
Nousaine wrote:
"Paul Vina" wrote: It would be nice if I didn't have to drive 45 miles to my old shop to use their meter, but it's cheaper than buying one! If my place is closer come over here Key up the Barry White music, as Tom opens the door. He's holding a couple of glasses in one hand, and a bottle of wine in the other... -- ------------------------------------------------------------------ | Lizard | thelizman1221.yahoo@com | ------------------------------------------------------------------ | teamROCS #007 / Technical Director / Founding Member | ------------------------------------------------------------------ | The TeamROCS Forum http://www.teamrocs.net/forum/ | | | | The Hoam Paige http://www.geocities.com/thelizman1221/ | | ------------------------------------------------------------------ |
#86
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Subwoofer direction
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#87
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Subwoofer direction
"Paul Vina" wrote:
Where are you at? Southeastern Michigan. |
#88
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Subwoofer direction
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#89
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Subwoofer direction
Oh well. I'm in N. CA
Paul Vina "Nousaine" wrote in message ... "Paul Vina" wrote: Where are you at? Southeastern Michigan. |
#91
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Subwoofer direction
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#92
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Subwoofer direction
Nousaine wrote:
This argument is a red-herring. Yes it's true that a good sounding system will have a gradually decreasing frequency response at about 3 dB per octave over the spectrum at the listening position. Sorry to step into this heated thread... This 3 dB per octave will cause a 20 kHz sound to be 30 dB lower than a 20 Hz sound, is this what you are saying? This could well be true but it's quite surprising at first glance! -- Eric (Dero) Desrochers Hiroshima 45, Tchernobyl 86, Windows 95 |
#93
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Subwoofer direction
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#94
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Subwoofer direction
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#96
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Subwoofer direction
Nousaine wrote:
But what happen to the old concept that bass is omnidirectionnal? Or more exactly, frequencies whose wavelenght are over three time the diameter of the reproducing driver are non directionnal? They still hold true. The main difference is that in your home 80 Hz is 2 standard deviations below the frequency at which people can generally locate a subwooer. In your car the people at Ford Audio found that 150 Hz (an octave up) was the typical frequency where low frequencies began to become directional. So, a typical in-car driver reproducing frequencies below 80 Hz in a linear fashion *is* omni-directional and humans cannot locate it either. It would seem to render moot any sub "aiming" concept... No "near-field" has a specific meaning that in engineering terms means that the microphone is within a half inch of the diaphram at low frequencies and sees basically the anechoic response of the speaker. I stand corrected. I was under the impression that multi-way systems (at least home speakers) were measured at 1 meter so to acount for the inter-driver interaction. At the critical distance where the reflected sound is equal in intensity to the direct sound we enter the far-field. In your car the radiating surfaces are so close to the interior surfaces the listener is always in the far field. (the amount of reflected sound is equal to or greater than direct sound.) OK Because there is no 'direct field' in the car and the space is much smaller. In a similar way the acoustics of the living room differ from a concert hall. But the effect on system tuning is that many people become irritated with the equalization process because the try to make the system "flat" in the far field without taking the slope into account and find it doesn't sound good. Indeed. Any attemps to have 16 kHz at the mid range level proved to be ear tearing! But in a car using multiple drivers (ie sub in back, low-mid in doors and tweeter on dash, how youd you approach frequency response measuring? Adjust each driver individually to be flat in near-field or measure at the listening position and try for the 3 dB per octave slope? -- Eric (Dero) Desrochers Hiroshima 45, Tchernobyl 86, Windows 95 |
#97
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Subwoofer direction
Eric Desrochers wrote:
So, a typical in-car driver reproducing frequencies below 80 Hz in a linear fashion *is* omni-directional and humans cannot locate it either. It would seem to render moot any sub "aiming" concept... Its NOT the same thing! Your talking about something completely different! The OMNI Directional you seem to be talking about is really called LOCALIZATION.... Which means a human cant localize low frequencies... In other words, its easy for us to tell where highs are coming from, but as sound gets really low the source of the sound is hard for us to find just by listening... This means that in a room (or car) you can place the woofer anywhere you want to and you wont mess up the imaging... From a localization point of view, the location of the woofer in relation to the highs is unimportant because the bass doesnt appear to come from one place, it appears to come from everywhere.. The reason is because the distance between our two ears is much shorter than the wavelengths for this bass. On the other hand, this thread isnt talking about that at all.!! Its not being able to tell where the woofer is with yrou ear, it is the woofer playing louder into the listening area by positioning the woofer at the optimal place in the car... I wrote a paper on it http://www.installer.com/tech/aiming.html Every kid with a car stereo knows the bass is better when the box is turned around backwards so the woofer itself is closer to the back of the car. Tom on the other hand says it makes no difference in the amplitude of the bass in the listening area and all these folks must be imagining it.... Eddie Runner |
#98
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Subwoofer direction
Eddie Runner wrote:
The OMNI Directional you seem to be talking about is really called LOCALIZATION... No. The imprecision of the human ear to discern low frequency is well known, but in this case I was really talking about a sub driver being omni-directionnal. Quote from the Loudspeaker Design Cookbook, by Vance Dickason : "At frequencies where the wavelenght of sound is large compared to the diameter of the cone, the radiation is spherical". Go to any pro audio gear manufacturer and look at the polar plot or specs of their subwoofers offering (by subwoofer I mean some cubic enclosure containing a 18 inches driver meant to produce sub-low frequencies). A few examples : http://www.meyersound.com/products/m...ifications.htm http://www.apogee-sound.com/pdfs/aplSB-spec.pdf Others, like JBL, Martin Audio, EV and EAW don't even bother with posting directivity speacs because it's so well known they are omni. Or do Google search with key words "bass sound directivity", "subwoofer polar plot", low frequency directivity, etc. -- Eric (Dero) Desrochers Hiroshima 45, Tchernobyl 86, Windows 95 |
#99
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Subwoofer direction
Eric Desrochers wrote:
No. The imprecision of the human ear to discern low frequency is well known... ....should have been "to discern low frequency location", of course. Sorry! -- Eric (Dero) Desrochers Hiroshima 45, Tchernobyl 86, Windows 95 |
#100
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Subwoofer direction
OK, good enough... Yes your right, the sound eminating
from the woofer does radiate out omnidirectionally... It is very common for folks to use the omnidirectional wording to describe our inability to localize low frequencies... Now that were straight and in agreement on that point.... You said before that since its omnidirectionional the placement of the woofer box is not a factor.... this is what made me thin you meant localization! For localization the placement of the wooferbox isnt important BUT, for placement in the vehicle for the least cancelation the omnidirectional output of the wooferbox is EXACTLY one of the factors that causes the problems I describe in my paper..!! Notice in my CARTOON drawings, when the woofer plays there is a sound that goes into the vehicle and also a sound that goes to the back of the vehicle ! This demonstrates the omni output of the box... So, its precisely this multidirection output that allows the bad reflections to happen! I hope this is understandable... Tom there shinks it DOESNT HAPPEN... But most of us here know he is wrong... Eddie Runner Eric Desrochers wrote: Eddie Runner wrote: The OMNI Directional you seem to be talking about is really called LOCALIZATION... No. The imprecision of the human ear to discern low frequency is well known, but in this case I was really talking about a sub driver being omni-directionnal. Quote from the Loudspeaker Design Cookbook, by Vance Dickason : "At frequencies where the wavelenght of sound is large compared to the diameter of the cone, the radiation is spherical". |
#101
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#102
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Subwoofer direction
Eddie Runner wrote:
OK, good enough... Yes your right, the sound eminating from the woofer does radiate out omnidirectionally... It is very common for folks to use the omnidirectional wording to describe our inability to localize low frequencies... Now that were straight and in agreement on that point.... You said before that since its omnidirectionional the placement of the woofer box is not a factor.... Hum, no. I have not talked about placement of the box, I have talked about it's orientation, "aiming", which are two different things, of course. I do sound reinforcment as part of my day job and I'm into big home theater here, so I know very well that the placement of a sub enclosure will make or break a system. But this whole thread was about the orientation of the sub (aiming, pointing). So I submitted that a woofer is omni-directionnal, which you seem to agree with, therefore you cannot "aim" an omnidirectional driver, which is where we seem to diverge opinion. A flashlight (tweeter) can be aimed because it's directional. A bare light bulb (woofer) cannot because it's omnidirectional. If so, how can having a woofer shooting into the rear hatch be any better than shooting to the rear seat? Having the box closer to the rear of the car however is different : you are not only aiming it, you are *moving* it, which *may* change something due to the (possible) better loading of the driver. Just like puting a home sub near a wall or near a corner will reinforce it. My 0.02$ -- Eric (Dero) Desrochers Hiroshima 45, Tchernobyl 86, Windows 95 |
#103
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Subwoofer direction
o I submitted that a woofer is omni-directionnal, which you seem to
agree with, therefore you cannot "aim" an omnidirectional driver, which is where we seem to diverge opinion. If, as you contend, the subs are omni and they cannot be aimed then take your pro sound subs and turn them around being careful that they stay on the same plane. Do you think you will notice a difference in FOH? What about onstage? A flashlight (tweeter) can be aimed because it's directional. A bare light bulb (woofer) cannot because it's omnidirectional. A woofer most certainly can be aimed. Even a SUBwoofer can be aimed. If so, how can having a woofer shooting into the rear hatch be any better than shooting to the rear seat? Look at Eddies cartoons, it is all there. Les |
#104
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Subwoofer direction
Eric Desrochers wrote:
Hum, no. I have not talked about placement of the box, I have talked about it's orientation, "aiming", which are two different things, of course. well ok then, placement of the woofer, not the box... If you aim a woofer *box* at you the woofer will be at point X if you aim the woofer box away from you keeping the *box* in the exact same place, the woofer will move to the other side of the box, and the woofer will now no longer be at X, it will be the width of the box further away from you.... So, aiming a woofer is usually achieved by turning the box, its not actually the aiming of the woofer that makes the differences we hear, but instead, its the position of the woofer changing relative to the vehicle and our listening area in the vehicle... And as pinted out in my cartoons, aiming the box IS moving the woofer.... (TYPICLY).... I do sound reinforcment as part of my day job and I'm into big home theater here, so I know very well that the placement of a sub enclosure will make or break a system. But this whole thread was about the orientation of the sub (aiming, pointing). Good enough, I guess it was stupid of me to assume you read my paper and understood that although the paper is titled AIMING it is really about POSITIONING the woofer.... Having the box closer to the rear of the car however is different : you are not only aiming it, you are *moving* it, which *may* change something due to the (possible) better loading of the driver. Just like puting a home sub near a wall or near a corner will reinforce it. it sounds like were on the same page, I think if you had taken 2 minutes to read my article on this you would have been quick to agree ... Eddie Runner http://installer.com/tech/aiming.html BTW, I titled the article AIMING because thats what the kiddos percieve as the change, even though anyone that reads the article can easily see its really position of the woofer itself that matters.... If I called the article something else, all the kids that turn the box around backwards in thier trunk and AIM the woofer to the rear would probably never find my article.... |
#105
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Subwoofer direction
Soundfreak03 wrote:
If, as you contend, the subs are omni and they cannot be aimed then take your pro sound subs and turn them around being careful that they stay on the same plane. Do you think you will notice a difference in FOH? What about onstage? For a single 12 inches non-horn loaded playing below 80 Hz, I'll bet it would not change a thing. Actually, if there is some wall behind the speaker, you may notice an increased output. However, a stack of 18 inches playing to, say, 120 Hz would be quite different because the mutual coupling of multiple drivers would cause some directivity in the higher bass. Meyer went to great lenght to design a "cardioid" sub and the thing have 4 drivers, weight 400 lbs, need extensive on-board processing and huge power to run. It's certainly not commonplace yet. If you know of a single 12, 15 or 18 inches pro sub that have some directivity below 80 Hz, please post references. -- Eric (Dero) Desrochers Hiroshima 45, Tchernobyl 86, Windows 95 |
#106
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Subwoofer direction
Eddie Runner wrote:
well ok then, placement of the woofer, not the box... If you aim a woofer *box* at you the woofer will be at point X if you aim the woofer box away from you keeping the *box* in the exact same place, the woofer will move to the other side of the box, and the woofer will now no longer be at X, it will be the width of the box further away from you.... So, aiming a woofer is usually achieved by turning the box, its not actually the aiming of the woofer that makes the differences we hear, but instead, its the position of the woofer changing relative to the vehicle and our listening area in the vehicle... And as pinted out in my cartoons, aiming the box IS moving the woofer.... (TYPICLY).... It would be in a small car, but say you have some mini-van. Turning the box over would only marginally change the distance from you. If you really meant "moving", you should have used that term. I guess I'm overly nitpicking about the terms! Good enough, I guess it was stupid of me to assume you read my paper and understood that although the paper is titled AIMING it is really about POSITIONING the woofer.... it sounds like were on the same page, I think if you had taken 2 minutes to read my article on this you would have been quick to agree ... I did read your page. Eddie Runner http://installer.com/tech/aiming.html BTW, I titled the article AIMING because thats what the kiddos percieve as the change, even though anyone that reads the article can easily see its really position of the woofer itself that matters.... If I called the article something else, all the kids that turn the box around backwards in thier trunk and AIM the woofer to the rear would probably never find my article.... I think that "placement of a sub enclosure in cars" is as catchy that "aiming a sub..." but it's just me! BTW, I browsed to your other papers too. Interesting stuff! Especially the part about the tight bass! Often confused with frequency response anomalies, like you pointed out, or the damping of the system. I always laught when I hear about 8 inches being more tight than 12 inches! Regards, -- Eric (Dero) Desrochers Hiroshima 45, Tchernobyl 86, Windows 95 |
#107
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Subwoofer direction
For a single 12 inches non-horn loaded playing below 80 Hz, I'll bet it
would not change a thing. How much? Go to your venue and turn your subs around then. Or hell just walk into the front of the sub then to the rear and you tell me if there is a difference or not. Actually, if there is some wall behind the speaker, you may notice an increased output. Perhaps, but you would most likely end up with some very odd delay times on the subs. However, a stack of 18 inches playing to, say, 120 Hz You cross over 18s at 120?!?! Seems a little high for SUBwoofers. Let your midbass speakers take care of that. would be quite different because the mutual coupling of multiple drivers would cause some directivity in the higher bass What does the multiple drivers have to do with it? But nonetheless you shouldnt have higher bass in your subwoofers. Meyer went to great lenght to design a "cardioid" sub and the thing have 4 drivers, weight 400 lbs, need extensive on-board processing and huge power to run. It's certainly not commonplace yet. Heard both of them, the PSW-6 and the M3D Sub. They are great. You walk onstage and you cant hear it, definantly takes care of some of the stage rumble. And they are definantly directional. I am not saying other subs are not but their output between the front and back is definantly different. If you know of a single 12, 15 or 18 inches pro sub that have some directivity below 80 Hz, please post references. Meyer 650-P. There is a 6dB loss off axis. That is a signifigant difference in any world but especially the world or PRO sound. Almost any line array sub, DVDOSC, X-Line, M3Ds, 760 line array. The Yorkville PS18. All of them have atleast a 6db loss at the rear. Subs are omnidirectional somewhat, they are in the sense that Mid/Highs are not. But even alot of subs are not truly omnidirectional, some can cover 360degrees horiz. BUT only 180 vertical at best. Look at Meyers site they or EAW have those specs published. Les |
#108
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Subwoofer direction
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#109
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ha ha ha Tom changes his story! Subwoofer direction
Nousaine wrote:
Holy Cow; who hasn't known that placing the face of a woofer near a boundary changes the systen tuning? Holy Cow! You must have missed that in my *cartoons* ha ha ha NOW, your changing your mind to say that moving a sub around in a car WILL make a difference?? Is that what I am starting to hear from you now??? ha ha ha in fact... ha ha ha, ha ha ha, ha ha ha! Eddie Runner You knew it all along! ha ha ha ha ha ha ha ha ha ha ha ha ha ha!! and ha ha ha ha ha and even ha ha ha ha! (im still laughing) |
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