Omega does this design as a 1.5 way speaker. With the ms11 I dont see the need for a x-over. Both of the drivers running fullrange as a 1 way
It is fairly easy to double the number of A11ms. Just increase the appropriate dimensions to get a box twice as big and use the equivalent of 2 vents.
With 2 it might be possible to push them further.
I would not configure the drivers as they have done in those Omegas. There are a number of ways to connect the 2 drivers, personally i like the series wiring with a shunt cap (assumes a voltage amp).
http://www.planet10-hifi.com/downloads/Dual-Driver-Wiring.pdf
There are 3, or 4 configuratuions for the drivers (can’t find the drawing), 2 on front, 1 on front 1 on back, 1 on front 1 on side (mirror imaged pairs, and if end loaded or not a TL, 1 on front 1 on top.
3 (possible impedance issues) or 4 drivers are also doable.
The A11ms probably drops right into these (i will check with Scott),
http://wodendesign.com/downloads/Quadrapole-P11-MLTL.pdf
http://wodendesign.com/downloads/TwinP11-Standmount.pdf
dave
With 2 it might be possible to push them further.
I would not configure the drivers as they have done in those Omegas. There are a number of ways to connect the 2 drivers, personally i like the series wiring with a shunt cap (assumes a voltage amp).
http://www.planet10-hifi.com/downloads/Dual-Driver-Wiring.pdf
There are 3, or 4 configuratuions for the drivers (can’t find the drawing), 2 on front, 1 on front 1 on back, 1 on front 1 on side (mirror imaged pairs, and if end loaded or not a TL, 1 on front 1 on top.
3 (possible impedance issues) or 4 drivers are also doable.
The A11ms probably drops right into these (i will check with Scott),
http://wodendesign.com/downloads/Quadrapole-P11-MLTL.pdf
http://wodendesign.com/downloads/TwinP11-Standmount.pdf
dave
I would go with both in front, verticall aranged. Will narrow the verticall spread some, due to beaming. Won't be harmfull for horizontall soundstage?
I'd than probably go for double nostromo demensions, internall and wide baffle. Had the ms11's one wide baffle before, was amazing. The ms11's sounded "bigger" on that baffle
How does that work, i.e. assuming one has the room to place these totem poles 4' from back and side walls, will the four A-11MS drivers 360 degrees orientation per cabinet assumed to be wired in series and parallel still yield a 3db gain making it a 91db efficient 7.2Ω impedance speaker?
A-11MS on sale @ Madisound for $85 x 8 = $680 ... Or spend $650 a pair of 70th Anniversary LE FE-103A's to put in a cabinet and actually use rather than keeping in display box on a shelf like a trophy to my old age which I can't imagine doing without first having gone thru a Covid-19 swab test frontal lobotomy???
4 drivers give 6 dB more sensitivity/efficiency.
They need a big room. It could be halved for a pair of drivers. 3dB increase in efficiency 6dB sensitivity (4Ω).
$650 for FE103A is a collector’s item price, to be collected and never used. I have at least 4 vintage FE103A on my shelf.
For that money you can get a lot more sonics and sound.
dave
They need a big room. It could be halved for a pair of drivers. 3dB increase in efficiency 6dB sensitivity (4Ω).
$650 for FE103A is a collector’s item price, to be collected and never used. I have at least 4 vintage FE103A on my shelf.
For that money you can get a lot more sonics and sound.
dave
^ right, but by wiring the 4 drivers in series and parallel you lose 3db of that 6db gain in keeping with the single 88db driver impedance which is 7.2Ω not 8Ω, bringing the sensitivity back down to 91db. I was questioning if that works out the same with the individual drivers all on adjacent walls to one another rather than the four drivers per side all on a single forward-facing baffle.
Last edited:
7.2Ω is the DC resistance not the impedance.
You gain 3 dB every time you double the drivers. Same impedance (series/parallel) means 2.83 V is 1w. 6dB increase in efficiency, 6dB more sensitive.
With 2 drivers in parallel you gain 3dB due to doubling the drivers and 3dB because 2.83v now gives 2w. 3dB increase in efficiency, 6dB more sensitive.
There will be differences in the on-axis sensitivity (with no room) but power response is the same depending on how you place the drivers on the 4 vertical surfaces.
dave
You gain 3 dB every time you double the drivers. Same impedance (series/parallel) means 2.83 V is 1w. 6dB increase in efficiency, 6dB more sensitive.
With 2 drivers in parallel you gain 3dB due to doubling the drivers and 3dB because 2.83v now gives 2w. 3dB increase in efficiency, 6dB more sensitive.
There will be differences in the on-axis sensitivity (with no room) but power response is the same depending on how you place the drivers on the 4 vertical surfaces.
dave
^ P10 Dave, I think we are saying the same thing only you did so in a not so clear way where you lost me, much the same as many technical questions go around here, in that you cited volts, 2.83v = 1watt vs 2.83v = 2watts, confusing.
Simply put for clarity:
Two drivers, combined impedance will be half of a single driver when wired in parallel, and twice of a single driver when wired in series.
Sensitivity increase +3dB for a parallel wiring and -3dB wired in series as compared to a single driver.
Cone excursion will be half of a single driver (would = less distortion).
Four drivers in series parallel will have 6dB efficiency gain over single driver. Doubling the cone area over the driver design adds 3dB, only putting two parallel wired drivers in series decreases gain by -3dB = a zero net change when compared to the output of two driver system.
Simply put for clarity:
Two drivers, combined impedance will be half of a single driver when wired in parallel, and twice of a single driver when wired in series.
Sensitivity increase +3dB for a parallel wiring and -3dB wired in series as compared to a single driver.
Cone excursion will be half of a single driver (would = less distortion).
Four drivers in series parallel will have 6dB efficiency gain over single driver. Doubling the cone area over the driver design adds 3dB, only putting two parallel wired drivers in series decreases gain by -3dB = a zero net change when compared to the output of two driver system.
Last edited:
It can be. 2,83 V into 8Ω is 1w, 2.83 V into 4Ω is 2w (2.83 into 16Ω is half watt. This is how sensitivity is measured and very useful when designing multi-way speakers (assuming you ar eusing a voltage amp)
For day to day use sensitivity is typically the more usefiul figure.
Cone excursion will be one fourth.
dave
Assuming multiple drive units of identical type:
-Each doubling of cone area yields +3dB
-Series wiring a pair of drive units doubles impedance, which in turn halves current draw. The nominal -3dB loss caused is cancelled out by the doubled cone area, resulting in no net gain or loss in SPL for the same signal input, but halved individual unit excursion and distortion.
-Parallel wiring halves impedance, doubling the current draw so results in an increase of +3dB. This is accompanied by another +3dB from the doubled cone area, providing a net increase in +6dB output relative to a single unit for the same signal input, at the same individual excursion and distortion levels.
Series-parallel wiring of 4 drive units (2 series pairs wired in parallel) yields the same impedance as one drive unit, but +6dB for the same signal input as cone area has quadrupled. Individual unit excursion & distortion is 1/4 that of a single unit for the same SPL.
The quadratic / quadrupole configuration is relatively unusual; the above still applies however, notwithstanding the idiosyncratic polar response as the total amount of energy radiated into the room is the same. You will get some losses as frequency increases in both cases (direct and quadratic) through destructive interference / interactions, albeit the details vary.
-Each doubling of cone area yields +3dB
-Series wiring a pair of drive units doubles impedance, which in turn halves current draw. The nominal -3dB loss caused is cancelled out by the doubled cone area, resulting in no net gain or loss in SPL for the same signal input, but halved individual unit excursion and distortion.
-Parallel wiring halves impedance, doubling the current draw so results in an increase of +3dB. This is accompanied by another +3dB from the doubled cone area, providing a net increase in +6dB output relative to a single unit for the same signal input, at the same individual excursion and distortion levels.
Series-parallel wiring of 4 drive units (2 series pairs wired in parallel) yields the same impedance as one drive unit, but +6dB for the same signal input as cone area has quadrupled. Individual unit excursion & distortion is 1/4 that of a single unit for the same SPL.
The quadratic / quadrupole configuration is relatively unusual; the above still applies however, notwithstanding the idiosyncratic polar response as the total amount of energy radiated into the room is the same. You will get some losses as frequency increases in both cases (direct and quadratic) through destructive interference / interactions, albeit the details vary.
Last edited:
TY, I'm a bit of a fan of old EPI speakers and have a few of them. I like the simple crossover networks. Reading of the Quadrapole being Inspired by EPI M1000 quadratic towerspeaker piqued my interest.
RE: multiple drivers 2, vs 4 wired in series and parallel, I got my information from Vance Dickason Loudspeaker Design Cookbook, not word for word, he used the word connected where I used wired and such so as not to create a word for word copyright issue. He also has computer sims showing the sensitivity and impedance gains and losses which are consistent with what he wrote.
Am I misinterpreting Dr Scott's explanation or are we saying Vance Diclason's information on the subject is wrong?
Can you or someone else post transfer functions showing what I think is a claim of 4 drivers wired in series and parallel +6db gain over a single driver while maitaining same impedance as a single driver?
Last edited:
I guess, becasue what he says is correct. Double the drivers gives 3dB. Wire in parallel, you get half the load, so twice the power (+3DB). In series, double the load, half the power (-3dB).
I’m pretty sure he said the same thing you did althou yours was not quite as complete.
dave
And yet I have absolutely no problem understanding what Vance Dickason wrote WRT 4 drivers wired in series and parallel.
You claim Scott said the same. In that case once again the writing has me completely lost because I see his explanation as saying wiring four drivers in series and parallel yeilds a gain of +6dB over a single drive unit with the impedance remaining that of the single drive unit, when in fact according to Dickason it only yeilds a gain of +3dB over a single drive unit while retaining the impedance of a single drive unit, i.e., single 8ohm driver.
To me, the above quote reads: (example), 1 drive unit of 90dB 8Ω. Wire 4 of those 90dB 8Ω drives unites in Series and Paraellel = 96dB 8Ω
Which would be incorrect as the 4 90dB 8Ω drive unites wired both in series and parallel = 93dB 8Ω.
Last edited:
Last edited:
In a series parallel connection you are quadrupaling (doubking twice) the number of drivers so you get 6dB.
YOu are misinterpreting Dickason.
dave
YOu are misinterpreting Dickason.
dave
No
Example: What you said reads as 1 drive unit of 90dB 8Ω (2.83 V into 8Ω 1 watt). Wire 4 of those 90dB 8Ω (2.83 V into 8Ω 1 watt) drives unites in Series and Paraellel = 96dB 8Ω (2.83 V into 8Ω 1 watt).
Which would be incorrect as the 4 90dB 8Ω (2.83 V into 8Ω 1 watt) drive unites wired both in series and parallel = 93dB 8Ω (2.83 V into 8Ω = 1 watt)
Last edited:
Dickason says that when you connect double the drivers you get +3dB.
1 driver is 90 dB, 2 drivers are 93 dB (double the drivers again). Double the drivers again and you get 96 dB.
In series/parallel you have the same impedances so same power. 0 dB difference.
So +6dB with 4 drivers wired series/parallel.
Wire 2 (two +3dB) in parallel, you+3dB due to 2x the power. So +6dB. But the amp has to be happy into the lower impedance. And half the excursion.
dave
1 driver is 90 dB, 2 drivers are 93 dB (double the drivers again). Double the drivers again and you get 96 dB.
In series/parallel you have the same impedances so same power. 0 dB difference.
So +6dB with 4 drivers wired series/parallel.
Wire 2 (two +3dB) in parallel, you+3dB due to 2x the power. So +6dB. But the amp has to be happy into the lower impedance. And half the excursion.
dave
I suspect you may have misread what Vance said, or there is an error in the LDC. Which can happen in the best publications -the LDC isn't great on TLs for example, and various editions have had 'issues' in text on crossovers etc. Anyway, what Dave and I wrote above is correct: assuming identical drivers, then
-Every doubling of cone area yields +3dB for a given signal input. No mysteries there, been known for decades.
-Wiring a pair of identical drivers in parallel halves the impedance and doubles the current, giving you another +3dB for a net +6dB gain relative to a single unit. All well known & documented.
-Wiring a pair of drivers in series doubles impedance and halves current draw. You therefore lose 3dB for a given signal input but this is cancelled out by the doubled cone area, so the series pair has no net dB gain or loss over a single unit. As above, well-known & documented.
-4 drivers wired in series-parallel for the same nominal impedance as a single unit sees +6dB net gain over a single unit resulting from the quadrupled cone area. Same as above, we use this all the time in array design, and several of my old commercial multiway designs in fact ran a quad of series-parallel midbass units.
Last edited: