I have issues with Planet10 on soldering the connections with a line array with SB65 drivers. There is a discussion on this subject in my thread on my Modified CBT at:
My New Line Array--It's a Modified CBT24
Read starting with message #51 about attaching wires to the connectors on the SB65 drivers. Patrick Bateman had no luck with soldering and was hindered by the delicate plastic frames of the small drivers. The clips that I suggest aren't ideal but way better than soldering. If you have a deft touch, soldering might work but I don't suggest it for average or less soldering skills.
Second, my comment on Dave's suggestion of using CAT5/6 wiring strands for a line array is that I used 16 gauge wiring for my Modified CBT24 arrays. Much better that a few wimpy strands of CAT5 wiring IMO.
My New Line Array--It's a Modified CBT24
Read starting with message #51 about attaching wires to the connectors on the SB65 drivers. Patrick Bateman had no luck with soldering and was hindered by the delicate plastic frames of the small drivers. The clips that I suggest aren't ideal but way better than soldering. If you have a deft touch, soldering might work but I don't suggest it for average or less soldering skills.
Second, my comment on Dave's suggestion of using CAT5/6 wiring strands for a line array is that I used 16 gauge wiring for my Modified CBT24 arrays. Much better that a few wimpy strands of CAT5 wiring IMO.
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Hi Jim,
Thanks for the info. I've re-read that section in your thread regarding connections and since I basically solder for a living, I'm going that route
. My solder skills are much much greater than my mechanical skills hehe. I have tested soldering a few drivers and it seems like no problem.Just thinking out loud:
Regarding the wire, lets say someone is crazy enough to pump 150 Watts into this array (maybe me lol). Since P = IIR we are looking at 6.12A total going through the LA. Since I'm doing a string of 6 in parallel we are looking at around 1A per driver = around 4 Watts per driver. According to a quick sim this seems close to the max for this driver if taken low.
So it we run pairs of wire to the terminal, it should be able to carry this 1A of dynamic/music current. Also since we don't want the wire to increase in heat that much (sealed enclosure) it seems like we should stay with some reasonable amount of current carrying capacity. If one were to run a single pair of wire into the sub enclosure and then break off to the drivers, it would have to carry around 6A of dynamic/Music current.
One can argue music is not continuous sine wave of 20Hz so it can be relaxed a bit but I'm not sure exactly how far it can be pushed. Looks like if you ran pairs of wire to the back terminals you could get away with 22 awg but you 'might' be loosing some stuff on large current pushes. I do have a spool of smaller jacket 20awg which means much less weight on the terminals so I'm probably going to use that and run pairs to the back terminals.
I used to use 22ga solid copper hook up wire for my speakers as well. Recently I tried measuring the damping factor of my Class A amps with an 8ohm dummy load. There is a huge difference of having a DF of 25 with 2m of stranded 16ga copper and DF of 300 with 12ga solid copper Romex. It will sound similar, but where the difference can be heard is in the tightness of the bass on kick drums and such. It’s less sloppy with thicker wire. Maybe on small full range drivers not as much of an issue, but if you value driver cone control by the amp, it makes a difference.
Ok time for a useless thought exercise. Since drivers are a bandpass device but focussing on the low pass properties........
If you cascade six low pass filters you'll get different high frequency roll off with each series section. For argument let's say you have a 3rd order rolloff at 20khz then the last section will be down several dB as compared with the first section.
Now one might be able to argue that when sitting down the lower sections are closer to your ears than the upper sections and since high frequency rolls off with distance that should be ok.
According to a quick sim this is not an issue as the differences at 15khz are negligible but a case could be made that if you are making a floor to ceiling array using series sections and expect even frequency response you should use the most extended hf driver or one that extends to 25khz but in practice probably not an issue.
If you cascade six low pass filters you'll get different high frequency roll off with each series section. For argument let's say you have a 3rd order rolloff at 20khz then the last section will be down several dB as compared with the first section.
Now one might be able to argue that when sitting down the lower sections are closer to your ears than the upper sections and since high frequency rolls off with distance that should be ok.
According to a quick sim this is not an issue as the differences at 15khz are negligible but a case could be made that if you are making a floor to ceiling array using series sections and expect even frequency response you should use the most extended hf driver or one that extends to 25khz but in practice probably not an issue.
The cable is capable of handling the current asked so it is not overkill and has other pluses, including being e40 years i asy to solder. I say just try it. After 40 years i have totes with 18, 16, 14, 12, and 10 g OFC wire. For FR aps at least the skinny wire wins out sound wise.
Trying to solder anything larger makes it hard to solder to terminals, and with so much wire in parallel is not the right “tool” for the job.
dave
That just shows tat one has to carfully consider amp/speakers as a system. There is no one perfect damping factor for each individual speaker, it varies… and it is often FRs that benefit from amps with lower damping factors.
dave
Honestly, and no offense, but that sounds incredulous.
The gauge difference at only 2m can't start to account for such a swing in DF, no matter impedances, can it?
Are you saying an amp somehow knows the difference in solid and stranded wire?
As usual this is comes down to compromises/goals.
1. Wire for maximum extension SPL.
2. Wire for greater topology flexibility and possibly evenness.
Initially wanted some flexibility in testing different sectional delays and amplitudes but at the end of the day I'd like to simplify my current setup so I'm going for #1 above.
6 in parallel per section with the sections in series. Using 22 awg per driver brought out to the rear connectors and all soldered to the tabs/speaker posts. 22awg was chosen because I thought my 18awg was too heavy for the driver terminals, also 22 seems to be able to carry the desired current.
Turning on iron and will hopefully be done 1 section later tonight!
1. Wire for maximum extension SPL.
2. Wire for greater topology flexibility and possibly evenness.
Initially wanted some flexibility in testing different sectional delays and amplitudes but at the end of the day I'd like to simplify my current setup so I'm going for #1 above.
6 in parallel per section with the sections in series. Using 22 awg per driver brought out to the rear connectors and all soldered to the tabs/speaker posts. 22awg was chosen because I thought my 18awg was too heavy for the driver terminals, also 22 seems to be able to carry the desired current.
Turning on iron and will hopefully be done 1 section later tonight!
Amp doesn’t “know” anything. This is simply the measured DF - easy to measure with an Oscope. I was not a believer in thick cables until I did this myself. I use stranded 12ga on my main 2way speakers now.
Thick cables do indeed increase DF, but your previous example seems to be flawed. 12AWG has less than half the resistance of 16AWG, so will reduce DF by over half, but not nearly as much as your measurement suggested.
I didn't enjoy doing the math, but when something doesn't sit right, just can't help myself ;^).
The formula for calculating damping factor (DF):
DF= ZL / ZAMP + (RWx2)
Where:
ZL = The impedance of the loudspeaker(s)
ZAMP = The output impedance of the amplifier
RW = The resistance of the wire times 2 for the total loop resistance.
With the low output resistance/high damping factors of most amps, the speaker wire resistance becomes the major factor in the reduction of the total damping factor.
You gave an example of a DF of 300 at 8 ohms using 2 meters of 12 AWG.
12AWG wire is .00521 ohms/m x4 (2m each direction), the series wire resistance should be .02084 ohms.
300/8= .026666 ohms, ZAMP + (RWx2), leaves .005821 as ZAMP, the amp’s DF is therefore 1374 (assuming wire resistance and DF are correct).
16 AWG wire is .0132 ohms/m x4, the series wire resistance would be .0528 ohms. Add ZAMP, .005821 + .0528=.058621.
8/.058621=136.46 DF, not 25 as you measured “with an Oscope”.
That said, a DF of 25 is not "bad", but 136 would be plenty decent, a DF around 50 is high enough for critical listening in recording studios, 20 is "good enough" for PA.
Of course, a DF of 20 at the speakers would be high for many tube amps...
Art
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Hi Art,
A lot of it lies in contact resistance variations of how well the wire is connected and quality of the connection interface. I agree the calculations of wire gauge and stranded vs not stranded won’t work it perfectly in math - as you have shown. I was using a 5-way binding post and clamping the stranded wire into the screw down clamp as best I could. I don’t think that was as good as the gold plated banana plug I used which was soldered onto the solid 12ga. Also, I may have made a mistake in the gauge of the stranded wire, it may have been 18ga. Let me confirm later.
A lot of it lies in contact resistance variations of how well the wire is connected and quality of the connection interface. I agree the calculations of wire gauge and stranded vs not stranded won’t work it perfectly in math - as you have shown. I was using a 5-way binding post and clamping the stranded wire into the screw down clamp as best I could. I don’t think that was as good as the gold plated banana plug I used which was soldered onto the solid 12ga. Also, I may have made a mistake in the gauge of the stranded wire, it may have been 18ga. Let me confirm later.
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Gentlemen,
This is a line array thread. mlee has used common sense and chosen the speaker cable that is best for his application given his constraints.
There is a dedicated thread where you can go to discuss speaker cable ad nauseam. I don't subscribe to that thread for obvious reasons, and I'm guessing most of you don't either. Can we all agree to let it go for the health and sanity of this thread?
Time and a place...
Regards,
Owen
This is a line array thread. mlee has used common sense and chosen the speaker cable that is best for his application given his constraints.
There is a dedicated thread where you can go to discuss speaker cable ad nauseam. I don't subscribe to that thread for obvious reasons, and I'm guessing most of you don't either. Can we all agree to let it go for the health and sanity of this thread?
Time and a place...
Regards,
Owen
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