One more question:
How close must be matched the drivers? Is 5% difference in Qts acceptable?
BTW, how I need to matching the drivers? In which TS parameters? What is the most important?
Tyimo
How close must be matched the drivers? Is 5% difference in Qts acceptable?
BTW, how I need to matching the drivers? In which TS parameters? What is the most important?
Tyimo
Hallo!!
Is there anybody out there?!?
Factory built drivers has usually more than 10% tolerance.
Tyimo
Is there anybody out there?!?
Factory built drivers has usually more than 10% tolerance.
Tyimo
I think matching drivers in line arrays is much less important than in standard two ways or three ways or single driver speakers. In my lines I have 14 mid-base drivers in each tower. Any normal manufacturing variations will get averaged out among all the drivers. Use one of the speaker simulation software packages and see how much the curve changes with a 10% variation in Qts. You will find a pretty small change in the lowest octave. This is less important if you are crossing over to subwoofers at a frequency somewhat above the low end of your lines.
Just a point, but remember to keep those drivers close together too -the closer the better in my view, or you're going to run into all sorts of nasty problems, especially if you take the midrange drivers up a fair way before crossing over to the tweeter line. While onthe subject Dave -the array in picture you posted at the top of the page -aren't the drivers spaced apart a bit far? (that's a question to satisfy my own interest, not a criticism BTW!)
Personally, I'd go for power-tapering over a curved baffle. One of the primary advantages of line arrays to my way of thinking, as well as placing you entirely in the nearfield and so removing the room from the equation (always the most unpredictable aspect of any hifi setup) is the very broad 'sweet area' you get, as opposed to a narrow 'sweet spot' offered by most monopolar designs. Curving the front baffle is going to remove 90% of this at a stroke. If that doesn't matter, then so be it -it's quite a nice, holistic approach (& looks good if you have the cabinetry skills [which I lack!]), but to me, making a curved baffle will involve a whole lot more blood, sweat, tears and effort than altering a few wires.
if you go for the curved baffle approach, here's another, that's quite well documented, and even appears to have a couple of hats on the top! http://www.geocities.com/dmitrynizh/labaffles.htm
I suspect there's going to be some lobing going on here, but interesting for all that
Best
Scott
Personally, I'd go for power-tapering over a curved baffle. One of the primary advantages of line arrays to my way of thinking, as well as placing you entirely in the nearfield and so removing the room from the equation (always the most unpredictable aspect of any hifi setup) is the very broad 'sweet area' you get, as opposed to a narrow 'sweet spot' offered by most monopolar designs. Curving the front baffle is going to remove 90% of this at a stroke. If that doesn't matter, then so be it -it's quite a nice, holistic approach (& looks good if you have the cabinetry skills [which I lack!]), but to me, making a curved baffle will involve a whole lot more blood, sweat, tears and effort than altering a few wires.
if you go for the curved baffle approach, here's another, that's quite well documented, and even appears to have a couple of hats on the top! http://www.geocities.com/dmitrynizh/labaffles.htm
I suspect there's going to be some lobing going on here, but interesting for all that
Best
Scott
You are correct about keeping the drivers as close as practical. This is especially important as you start to get into the midrange >1khz. I think the curved baffle would actually act to reduce room interactions because it more tightly focuses the sound in the vertical dimension.
I think line arrays can lessen room interaction, but they do not get rid of room interaction (there will still be reflections off the rear walls, for instance; if anything, because of the concentrated effect of the line array as compared to a typical speakers, these later reflections might be worse in terms of being higher in power). Further, I wonder what the true effect of curving line arrays is? I bet it's not much. You'd have to build one set curved and one not curved and test the room effects in the same room.
Let me re-phrase -arrays can't actually remove room-interactions, as we all know, but the domestic variety are designed to be listened to in the nearfield as a general rule. Nearfield listening pretty much negates a rooms' influence because the vast majority of what you hear is directly radiated sound from the drive-units rather than indirect room resonances. Hence my comment above. You'll still get some room reflections of course; we live in the real world, not an ideal one, but the effect for the listener will be much reduced over what you'd get from a conventional monopole (like a regular floor-stander) which in the same physical location will be in the far-field.
Cheers
Scott
Cheers
Scott
Room Interactions with Line Arrays
Near field line arrays have the benefit that they minimize floor and ceiling reflections. Essentially, they contour their radiation so that minimal sound would strike these surfaces. Line arrays will have the same sidewall concentration as the individual drivers which comprise the array (you have used up all degress of freedom in the vertical axis and have effectively no control in the horizontal axis).
How speakers react with the side walls and rear wall (the wall behind the speakers) depends on their radiation characteristics. While all speakers will have potential for reflections from the wall behind the speakers, monopolar speakers will minimize the rear wall interaction above the baffle step point wherein they radiate outward to the listener. Bipolar and dipolar speakers have to be positioned far away from the rear wall to minimize interactions as they theoretically radiate equal energy forward and backward. Dipolar speakers have a theoretical null toward the sidewalls so in theory you would have no energy striking the sidewalls.
Bottom line is that in theory a dipolar (open back baffle for example) speaker would minimize speaker/room interaction. If you go for a near field line array with a dipolar radiation pattern you would have the best combination of all.
Finally, a concave or focused line array is a plenty dumb design in my opinion. What you are doing is limiting the listening area to the distance at which the array is focused. It is a one row of listeners ride. In contrast a near field array with a straight column will cover most of the listening room with what I call the sweet area ( a large area wherein the sound is well balanced).
More line array stuff in my white paper.
Jim
Near Field Line Array White Paper
Near field line arrays have the benefit that they minimize floor and ceiling reflections. Essentially, they contour their radiation so that minimal sound would strike these surfaces. Line arrays will have the same sidewall concentration as the individual drivers which comprise the array (you have used up all degress of freedom in the vertical axis and have effectively no control in the horizontal axis).
How speakers react with the side walls and rear wall (the wall behind the speakers) depends on their radiation characteristics. While all speakers will have potential for reflections from the wall behind the speakers, monopolar speakers will minimize the rear wall interaction above the baffle step point wherein they radiate outward to the listener. Bipolar and dipolar speakers have to be positioned far away from the rear wall to minimize interactions as they theoretically radiate equal energy forward and backward. Dipolar speakers have a theoretical null toward the sidewalls so in theory you would have no energy striking the sidewalls.
Bottom line is that in theory a dipolar (open back baffle for example) speaker would minimize speaker/room interaction. If you go for a near field line array with a dipolar radiation pattern you would have the best combination of all.
Finally, a concave or focused line array is a plenty dumb design in my opinion. What you are doing is limiting the listening area to the distance at which the array is focused. It is a one row of listeners ride. In contrast a near field array with a straight column will cover most of the listening room with what I call the sweet area ( a large area wherein the sound is well balanced).
More line array stuff in my white paper.
Jim
Near Field Line Array White Paper
Possibly the clearest & most open-minded description on the subject I've yet read. Cheers for that Jim.
Scott
Scott
parallel-series drivers
Hi!
I have somewhere in my PC a little program for calculating parallel-series connected driver impedance, but I don't remember the name and so I can't find it..... 🙂
Could you give me some help what is the best way to connect 8 drivers? ( both are 8 ohm )
Greets:
Tyimo
Hi!
I have somewhere in my PC a little program for calculating parallel-series connected driver impedance, but I don't remember the name and so I can't find it..... 🙂
Could you give me some help what is the best way to connect 8 drivers? ( both are 8 ohm )
Greets:
Tyimo
hi!!
Tyimo,take a look at jim griffin white paper ,you'll find all you need
but for a 8 speakers straight line whit a good balance,go on 4,2,2 design,if your speakers are 8ohms you'll got a 10 ohms dc resistance
for more efficiency go on 4,4 design whit a resulting dc resistance of 4ohms
hope it help you....
greet
Tyimo,take a look at jim griffin white paper ,you'll find all you need
but for a 8 speakers straight line whit a good balance,go on 4,2,2 design,if your speakers are 8ohms you'll got a 10 ohms dc resistance
for more efficiency go on 4,4 design whit a resulting dc resistance of 4ohms
hope it help you....
greet
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