Wire Gauge / Length affecting Dampening Factors

[Riflefeet]

So I'm at the point where my rig has been up and running for 9 months and it knocks hard and Ive made a big splash in the San Francisco electronic music community and starting to get bigger gigs with international touring acts, but I'm trying to tie up the loose ends and get rid of cheap shortcuts I took to get myself off the ground in the beginning as well as learn more about the details of how each element of the rig impacts the sound.

I've been running cheap-o inuke6000 amps and just this week upgraded to crown itech8000 amps for the eight (soon to be twelve) 24'' titan48s (loaded with 3015lf) and crown xti-6002 to run the two (soon to be four) omni15 w/ melded arrays. this should improve my sound in a number of ways, including clear and precise voltage limiting (the inukes are ALL over the place and require me to limit really hard to keep the system protected which guts a lot of the overall dB capability of the system) as well as a seriously improved dampening factor.

with what ive learned about dampening factor is that (as all things audio are) there are many people who claim having a high rating is not much use. that only tells part of the story. the inuke6000 has a DF rating of 140, where the itech8000 has a DF rating of 5000. but that only factors into a small part of the equation to calculate the actual DF of the system. in fact the wire length and gauge seem to have a much larger impact on overall DF than the DF rating of the amp itself.

to quote from this EAW article: http://eaw.com/amplifier-damping-factor ... -or-is-it/

"
Z(L)
divided by
Z(AMP) + (R(w) * 2)

equals

DF

Where:

Z(L) = The impedance of the loudspeaker(s)

Z(AMP) = The output impedance of the amplifier

R(W) = The resistance of the wire times 2 for the total loop resistance.

Very few amplifier spec sheets state the output impedance, but you can generally call the manufacturer for this spec or you can calculate it by dividing the minimum rated load impedance by the damping factor rating. For example, if we are using amplifier with a damping factor rating of 400 and it requires a minimum load of 2 Ohms, then its output impedance would be calculated as being 0.005 Ohms.



From what Ive read, the base minimum DF for sound reinforcement is around 20. I currently run 1 driver per channel (8ohms) but want to be able to run 3 per channel (2ohms) in order to limit the need to buy another 2-4 thousand dollar amplifier, and regardless of how many drivers per channel I have, I want to maximize my DF, period.

Ive been running 25' long 12awg speakons from my amps to my subs, and apparently gutting my DF in the process. On the inuke6000 with 8ohms on each channel I get a DF of 31, with two drivers on each channel @ 4ohms I get a DF of 15, with three drivers per channel @ 2ohms I get dismal DF of 7. With the same wire length and gauge with the itech8000 I get a DF of 100 @ 8ohms, 50 @ 4ohms, and 25 @ 2 ohms. Certainly that is a better scenario with the itech8000 but not as much of a difference as you might hope for with an amp that costs more than 10 times the other and boasts about its spectacular DF rating of 5000.

With that in mind I looked to mess around with wire length and gauge to see how much that would impact my overall DF and was STUNNED. If I switched to 10awg and placed my amps close to the subs and figure I could limit the wire length to 10' (likely the shortest possible length possible considering amp to sub jack, jack to driver, then linking each sub to each other) the DF with the itech8000 goes to 392 @ 8ohm, 196 @ 4ohm, and 98 @ 2ohm. now THAT is a big impact for very little investment.

To take it a step further, what if you dropped the wire to 6awg (resistance of .004)? I calculated that I could get a DF of 952 @ 8ohms, 476 @ 4ohms, and 238 @ 2ohms.

So doing all this made it clear that I need to rethink how I wire my system, where I place my amps, and how thick my wires should be. I've got plenty of experience building my own cables so I'm wondering, is there a limit to how useful this is? If I built cables with 6awg wire would that be ridiculous or not possible somehow (wire not fitting into connectors on the speakons or in the back of the drivers, etc)? If i'm going to scrap all my speakons to go with shorter and lower gauge wire I want to do it right once and for all and not be in this situation again where I have a bunch of cables which now feel like they are hindering my system.

Any thoughts/input/experience/advice would be greatly appreciated.

[Grant Bunter]

Damping factor as an issue is a dubious important parameter, depending on what you read.

Search harder for articles by Douglas Self and others to see both sides of the story.

Having said that, it isn't bad practice to keep amps closer to subs (by utilising longer balanced signal runs) and using heavier gauge wiring.

Also, look more into series/parallel wiring your subs.
The goal is to raise the overall impedance level to make your amps work less hard, ie, at 8ohms/channel rather than 4 or 2 ohms/channel.
As long as your amp has the required voltage swing to do this of course...

[Bill Fitzmaurice]

http://www.diyspeakers.net/Articles/Ric ... FACTOR.pdf

If damping factor mattered tube amps wouldn't work.

[CoronaOperator]

A/B your itech and inuke, can you hear any difference?

[Riflefeet]

A/B your itech and inuke, can you hear any difference?

They are still in the mail. I plan to do this, I can always return the itechs if it seems to be a waste of money.