wiring up a korean bass knob to more than two amps

[MickyMcD]

Raise BL by wiring in series? Now I have to google.

I cannot remember where I grabbed these images from, but it was very well laid out.

Cheers,

Mick

[MADVIBES]

nice illustration, thanks for sharing

[bassl0va]

There's no change to the subs specs by wiring it in parallel or series. There are individual changes to parameters, but they are complimentary and cancel each other out.

[MickyMcD]

There's no change to the subs specs by wiring it in parallel or series. There are individual changes to parameters, but they are complimentary and cancel each other out.

Yes and no. Compliance is complimentary and changes very slightly. Other parameters are not complimentary. Of course, the complimentary changes are only complimentary if you assume the current delivered to the loudspeaker is constant. This is not the case due to changes in the solenoid that are not complimentary.

You must understand that neither voice coil on the former is identical. The outer winding will have higher DC resistance due to the larger radii. If the coils have been formed bifilar then this is reduced, however the coil cross section is not always symmetrical and neither is the thickness of the extruded wire used to form the coil. Some voice coils are designed with a tapered middle section, some with a long taper towards the end of the former. No two solenoids are completely alike electromechanically.

BL rating has doubled with a series connection as the length of the solenoid is now 2xL. However, the length of the parallel coils is still L and current has halved between each coil, so for a parallel configuration versus series BL remains constant. If you are utilising maximum motor force for a particular design, this will impact you. While yes, the motor force is half the series configuration for parallel and yes, ideally the parallel configuration would receive the respective increase in current to match this change, it does not always occur in this way. The current delivery from the power amplifier is not a constant, and the changes in the impedance plot brought upon by solenoid configuration changes will greatly affect this.

Zmax changes drastically. Zmax is the maximum electrical impedance that occurs at the resonant frequency of the driver, Fs. As an example, a driver rated with a Zmax of 64.1 Ohm at 36Hz in series is now rated at 16.5 Ohm at Fs when in parallel. Inductance does not remain constant. There is a marked increase in Le between L and 2L solenoid lengths. The inductance of the solenoid forms a close relationship with the impedance curve. It should be seen that this vast increase in inductance consequently relates to the vast increase in Zmax. This will be a pronounced audible and measurable difference of the impedance plot of the driver and may be constructive or detrimental to the loudspeaker and cabinet system.

Mechanical ratings like Vas and Xmax/Xmech stay the same as the wiring configuration does not change the mechanical factors.

Total compliance will come to within one or at a stretch two percentage points either way, as will both mechanical and electrical compliance. In the ideal situation it would remain constant, though with a physically imperfect pair of solenoids this is not the case. The difference is absolutely minute and will not be audible to even the most trained ear.

Voltage sensitivity in the parallel voice coil has increased by six dB. This can be seen easily if the driver is specified in both dB/w/m and dB/2.73Vrms/m. As an example, a driver rated at 89.5dB/2.73Vrms/m in series has increased by this factor to 95.7dB/2.73Vrms/m. This is not the same as efficiency expressed in dB/w/m as this rating is at one Watt, regardless of the Revc or voltage sensitivity. If the impedance of the network changes, the amount of voltage and current signal to the driver is adjusted to achieve one Watt. For this reason, this style of efficiency measurement stays constant with an increase in voltage sensitivity.

Many manufacturers will specify in which configuration the loudspeaker was wired for TS testing or provide tables for both series and parallel wiring configurations. JBL Professional drivers, Faital, Ciare and even consumer manufacturers such as Boston. For the average and even above average loudspeaker user, these differences are minimal. But if you are designing a frequency dividing network or enclosure for the absolute closest relationship with the driver in use, these changes are more pronounced than you think.

As an aside point, you are a Kiwi! I had the absolute pleasure of skipping across the pond to see New Zealand and I doubt there is a more beautiful place on Earth. My wife and I are already preparing to go back as soon as we can. And you live there, you lucky bugger!

Cheers,

Mick

[bassl0va]

Thanks for your detailed reply. I wasn't aware that some are wound one coil on top of the other, I assume that's for ease of production? It seems like a trade-off and not what you want for best functionality and accuracy.
Makes sense that it affects passive crossovers, don't know how many guys run their subs with a passive xo though Or for that matter how many dual coil drivers get used with passive xo.

I've never seen anywhere any mention of it affecting enclosure design. I would have thought if it made drastic differences there would be a lot of info about what they are and how. Using only 1 of the coils certainly makes a difference though.


Yep
We certainly pay for it though, all the cool toys aren't cheap down here!

[MADVIBES]

I wanted to test my theory of series vs parallel trade offs in relation to maximum driver output at the enclosure's FS.

lets say for easy math If I had a 10" DVC sub and was to run 500 clamped watts to the driver wired in paralell and ran sweeps measuring output

from 20-60hz

then wired the sub in series and ran 500 clamped watts to the driver and retested the output at the same 20-60hz range

I wanted to see if there was any difference in output between the two if the wattage was the exact same for each driver's wiring

configuration.

for testing sake the test box would remain the same.

currently my four subs are wired in series to two pairs of strapped amplifiers @ 2ohm

If I wire them in parallel I would be at half ohm strapped which I know my amps will handle but was wondering if the power increase would make a huge difference in output. I realize the anser is test and find out, the only problem is it will cost me time and money. My rear window has to be removed to serive my subwoofers.

[MickyMcD]

Coils wound in layers is faster and cheaper to produce that bifiliar methods for sure. It is also very repeatable and offers similar specifications from driver to driver as they roll off the production floor. And for most users, the minute changes that bifiliar wiring affects over layered solenoids is a non-issue.

The enclosure must match the driver's properties exactly for the most efficient use of the air space in the enclosure. Every small electromechanical variance changes the way the moving mass interacts with the air space. Again though, the changes are small and you really are splitting hairs over less than five percent change in output and most likely less than five percent variance in frequency response. What changes drastically is the phase plot of the driver, and therefore the cabinet. If the increase in inductance vastly changes the phase plot or even to an extreme level, adds a phase rotation, the enclosure must be redesigned to combat or adjust this change.

The poor old electrical phase plot is often left at the back of the bus when comparing changes between drivers or driver configuration but it's importance is paramount.

Just about all JBL Differential Drive woofers are dual voice coil. 2269H can be ordered in various impedance too, which is nice. Dual voice coil loudspeakers are becoming more common in European offerings too from D&B, RCF etc etc etc. Often these units are used in completely active boxes with no frequency divider but often they are in passive boxes with a network. Many three way boxes are passively divided between the high frequency element and the mid frequency element with a separate input for the low frequency element.

Not wrong about the cost! I thought I was going to have heart attack at the cost of fuel, very much more expensive that Australia. But the country and its people are amazing. The South Island has me captured!

I wanted to test my theory of series vs parallel trade offs in relation to maximum driver output at the enclosure's FS.

lets say for easy math If I had a 10" DVC sub and was to run 500 clamped watts to the driver wired in paralell and ran sweeps measuring output

from 20-60hz

then wired the sub in series and ran 500 clamped watts to the driver and retested the output at the same 20-60hz range

I wanted to see if there was any difference in output between the two if the wattage was the exact same for each driver's wiring

configuration.

The tricky thing here will be to ensure that both loudspeakers receive exactly 500 Watts of power. If so, and everything being ideal, the level of pressure output should stay just about the same. The voltage sensitivity, frequency response and phase plot may and most likely will be very different, but the output pressure level should remain the same.

If you do try the experiment please share with us!

Cheers,

Mick

[Kyblack76]

Coils wound in layers is faster and cheaper to produce that bifiliar methods for sure. It is also very repeatable and offers similar specifications from driver to driver as they roll off the production floor. And for most users, the minute changes that bifiliar wiring affects over layered solenoids is a non-issue.

The enclosure must match the driver's properties exactly for the most efficient use of the air space in the enclosure. Every small electromechanical variance changes the way the moving mass interacts with the air space. Again though, the changes are small and you really are splitting hairs over less than five percent change in output and most likely less than five percent variance in frequency response. What changes drastically is the phase plot of the driver, and therefore the cabinet. If the increase in inductance vastly changes the phase plot or even to an extreme level, adds a phase rotation, the enclosure must be redesigned to combat or adjust this change.

The poor old electrical phase plot is often left at the back of the bus when comparing changes between drivers or driver configuration but it's importance is paramount.

Just about all JBL Differential Drive woofers are dual voice coil. 2269H can be ordered in various impedance too, which is nice. Dual voice coil loudspeakers are becoming more common in European offerings too from D&B, RCF etc etc etc. Often these units are used in completely active boxes with no frequency divider but often they are in passive boxes with a network. Many three way boxes are passively divided between the high frequency element and the mid frequency element with a separate input for the low frequency element.

Not wrong about the cost! I thought I was going to have heart attack at the cost of fuel, very much more expensive that Australia. But the country and its people are amazing. The South Island has me captured!

I wanted to test my theory of series vs parallel trade offs in relation to maximum driver output at the enclosure's FS.

lets say for easy math If I had a 10" DVC sub and was to run 500 clamped watts to the driver wired in paralell and ran sweeps measuring output

from 20-60hz

then wired the sub in series and ran 500 clamped watts to the driver and retested the output at the same 20-60hz range

I wanted to see if there was any difference in output between the two if the wattage was the exact same for each driver's wiring

configuration.

The tricky thing here will be to ensure that both loudspeakers receive exactly 500 Watts of power. If so, and everything being ideal, the level of pressure output should stay just about the same. The voltage sensitivity, frequency response and phase plot may and most likely will be very different, but the output pressure level should remain the same.

If you do try the experiment please share with us!

Cheers,

Mick

Coils wound top to bottom? Hmmm.... Wound together "over lapping" was what i though was norm. A coil on top and one on the bottom ? Am i reading you correct?

[MickyMcD]

Not quite Ky. It is common for one coil to be formed on the bobbin (former), then the next coil formed on top of the existing solenoid. So 'stacked' on top of each other if you will on the x and y axis but not the z, if you are taking the reference point as looking top-down on the bobbin. Or as you very rightly said overlapping. This is not the case when the solenoid is formed with bifilar windings as then the radii is mostly equal with the solenoids formed side by side along the length of the bobbin.

But no, not one solenoid at the base of the former and one at the junction between the bobbin and the cone or diaphragm. This would expose only a fraction of the solenoid length to the magnetic gap at any one instance and I'd think would measure and sound............interesting.

Does that answer your question clearly?

Sorry to the original poster for taking your thread off topic.

Cheers,

Mick

[MADVIBES]

Coils wound in layers is faster and cheaper to produce that bifiliar methods for sure. It is also very repeatable and offers similar specifications from driver to driver as they roll off the production floor. And for most users, the minute changes that bifiliar wiring affects over layered solenoids is a non-issue.

The enclosure must match the driver's properties exactly for the most efficient use of the air space in the enclosure. Every small electromechanical variance changes the way the moving mass interacts with the air space. Again though, the changes are small and you really are splitting hairs over less than five percent change in output and most likely less than five percent variance in frequency response. What changes drastically is the phase plot of the driver, and therefore the cabinet. If the increase in inductance vastly changes the phase plot or even to an extreme level, adds a phase rotation, the enclosure must be redesigned to combat or adjust this change.

The poor old electrical phase plot is often left at the back of the bus when comparing changes between drivers or driver configuration but it's importance is paramount.

Just about all JBL Differential Drive woofers are dual voice coil. 2269H can be ordered in various impedance too, which is nice. Dual voice coil loudspeakers are becoming more common in European offerings too from D&B, RCF etc etc etc. Often these units are used in completely active boxes with no frequency divider but often they are in passive boxes with a network. Many three way boxes are passively divided between the high frequency element and the mid frequency element with a separate input for the low frequency element.

Not wrong about the cost! I thought I was going to have heart attack at the cost of fuel, very much more expensive that Australia. But the country and its people are amazing. The South Island has me captured!

I wanted to test my theory of series vs parallel trade offs in relation to maximum driver output at the enclosure's FS.

lets say for easy math If I had a 10" DVC sub and was to run 500 clamped watts to the driver wired in paralell and ran sweeps measuring output

from 20-60hz

then wired the sub in series and ran 500 clamped watts to the driver and retested the output at the same 20-60hz range

I wanted to see if there was any difference in output between the two if the wattage was the exact same for each driver's wiring

configuration.

The tricky thing here will be to ensure that both loudspeakers receive exactly 500 Watts of power. If so, and everything being ideal, the level of pressure output should stay just about the same. The voltage sensitivity, frequency response and phase plot may and most likely will be very different, but the output pressure level should remain the same.

If you do try the experiment please share with us!

Cheers,

Mick

I was planning on using an over sized amp and testing wattage using a clamp and a DMM. Unless you think there may be a better way to make sure the sub reaches 500, I was under the assumption that the raise in BL by wiring in series would increase the motor force and help the ultra deep frequencies produce at a higher level.