Hi ... I recently made two needles with the Visaton FRS8 drivers.
I really love the sound these $10 drivers produce.
Now I wanted to make 4, for the 4.1 (sub is almost ready too
), but I found that my little daughter isn't that carefull ...
So I have 2 bookshelf speakers as rears, which will do for now.
I now have 2 FRS8 drivers left. And since I'm not really happy with the finish on the first Needles, I'd like to remake them.
Would it be possible to use 2 FRS8 drivers in 1 needle speaker ?
If so, what would I need to change ?
Any help would be greatly appreciated.
Cheers,
TDL.
I really love the sound these $10 drivers produce.
Now I wanted to make 4, for the 4.1 (sub is almost ready too
), but I found that my little daughter isn't that carefull ...So I have 2 bookshelf speakers as rears, which will do for now.
I now have 2 FRS8 drivers left. And since I'm not really happy with the finish on the first Needles, I'd like to remake them.
Would it be possible to use 2 FRS8 drivers in 1 needle speaker ?
If so, what would I need to change ?
Any help would be greatly appreciated.
Cheers,
TDL.
Ok ... thats out of the question I guess.
They're already 20cm long. Then they'd have to be 40cm long.
I've been searching some more, and I found some pictures of needles with two drivers, one in the front and one in the back. At the same heights ... but ... come to think of it ... they were twice the original height.
So, correct me if I'm wrong, but adding another driver means doubling something of the original design ... height, depth or lenght.
Is it possible to just make all the dimensions a bit bigger ?
On a sidenote ... would it be worth the effort ?
They're already 20cm long. Then they'd have to be 40cm long.
I've been searching some more, and I found some pictures of needles with two drivers, one in the front and one in the back. At the same heights ... but ... come to think of it ... they were twice the original height.
So, correct me if I'm wrong, but adding another driver means doubling something of the original design ... height, depth or lenght.
Is it possible to just make all the dimensions a bit bigger ?
On a sidenote ... would it be worth the effort ?
Hi,
You can mount them front and back as bipoles to use away from walls.
Theorectically you should double the internal cross sectional area, but
this depends on the CSA to driver CSA ratio you are already using, if
you are definetely rebuilding the cabs you can try 2 in your old cabs.
There is no reason why a bipole cannot be folded.
You could increase internal width to say 13cm and depth to say 30cm.
Effort ? 6dB more maximum output, 6dB more bass when used as
a bipole or 1.5way compared to the mid/treble level, 4 ohm load.
/sreten.
You can mount them front and back as bipoles to use away from walls.
Theorectically you should double the internal cross sectional area, but
this depends on the CSA to driver CSA ratio you are already using, if
you are definetely rebuilding the cabs you can try 2 in your old cabs.
There is no reason why a bipole cannot be folded.
You could increase internal width to say 13cm and depth to say 30cm.
Effort ? 6dB more maximum output, 6dB more bass when used as
a bipole or 1.5way compared to the mid/treble level, 4 ohm load.
/sreten.
Let me add to one of the statements that Sreten made. The statement was:
"Effort ? 6dB more maximum output, 6dB more bass when used as a bipole or 1.5way compared to the mid/treble level, 4 ohm load."
He is assuming two 8 ohms drivers which are connected in parallel in either a bipole or 1.5 way configuration. In the bass to mid region (typically from the baffle step compensation point and downward), you will have up to 6 dB more output vs. the mid/treble level as he says. Now 3 db of that 6 dB comes from the added acoustical efficiency (dual cones and sound field overlap) and 3 dB which comes from impedance sensitivity improvement (8 ohms to 4 ohms). Now above the BSC point any sensitivity improvement is solely due to impedance sensitivity increase. This results in 3 dB more sensitivity than a single driver monopulse raidator. In this case (above the BSC point) the sound fields radiated by the drivers on the front and rear of the bipole pair don't have any acoustical overlap so no acoustical efficiency increase results. Essentially, you get the same thing for the 1.5 way configuration you have the same output above the BSC point as the bipole assuming that you account for the baffle step with the 0.5 way driver.
"Effort ? 6dB more maximum output, 6dB more bass when used as a bipole or 1.5way compared to the mid/treble level, 4 ohm load."
He is assuming two 8 ohms drivers which are connected in parallel in either a bipole or 1.5 way configuration. In the bass to mid region (typically from the baffle step compensation point and downward), you will have up to 6 dB more output vs. the mid/treble level as he says. Now 3 db of that 6 dB comes from the added acoustical efficiency (dual cones and sound field overlap) and 3 dB which comes from impedance sensitivity improvement (8 ohms to 4 ohms). Now above the BSC point any sensitivity improvement is solely due to impedance sensitivity increase. This results in 3 dB more sensitivity than a single driver monopulse raidator. In this case (above the BSC point) the sound fields radiated by the drivers on the front and rear of the bipole pair don't have any acoustical overlap so no acoustical efficiency increase results. Essentially, you get the same thing for the 1.5 way configuration you have the same output above the BSC point as the bipole assuming that you account for the baffle step with the 0.5 way driver.
Halving the impedance (8 ohms to 4 ohms) means your amp puts out approx twice as much power (depending on amp). That's your first 3dB increase in output from the speakers.
Using two drivers gives you your other 3dB increase. BUT it doesn't go all the way into the treble. Expect the bass and mid-bass to be 3dB louder but the treble will stay the same. (At a certain distance apart, the two drivers will act as one driver with twice the surface area - equals more dB - above that distance, they act as two again and no increase in volume.)
Using two drivers gives you your other 3dB increase. BUT it doesn't go all the way into the treble. Expect the bass and mid-bass to be 3dB louder but the treble will stay the same. (At a certain distance apart, the two drivers will act as one driver with twice the surface area - equals more dB - above that distance, they act as two again and no increase in volume.)
Jim Griffin said:
Hi,
I would add that the apparent amount of BSC farfield for a bipole
is less than 1.5 way because there will be more midrange / treble
in the farfield diffuse soundfield, so in this case a bipole is the
most suitable (for relatively near wall). The jury is out on the
relative merits / effects of bipoles, whist axial anechoic output
is identical to a 1.5 way, perceived response is a different story.
/sreten.
TDLofCC said:Wow ... that kinda of went OVER my head there ...
English is nog my first language ... so thats making it even harder
So, if Henkjan would care to translate it to dutch ... I might be able to understand it ...
extreme samenvatting: hij legt uit dat je bij dipole en bij de 1½ weg configuaratie er alleen in t laag 6dB bij krijgt als je 2 drivers toepast.
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