Sundown 3000d installed

[iagrdshaka 5,000+ posts]

I was talking 0.25 nominal thanks R-tard 0.75 (if possible) reactive

//content.invisioncic.com/y282845/emoticons/laugh.gif.48439b2acf2cfca21620f01e7f77d1e4.gif

yea...

 

[NDMstang65 10+ year member]

uh dur, you act like I have no clue what I am talking, I simply said it would be nice to wire at 0.25 and see a final 0.75 thats BEFORE his box rise stupid a$$ now pay attention, its possible just would need a solid box with little box rise, which isnt an option for chad currently because he has already stated he has tons of box rise, because your a mod doesnt me your god step off the high horse kid and grow up there are other peopl out there that know alot about audio, not just you...thanks and have a nice day.

You wire any amp that low on a 16v system and your lookin' at a fireworks show. //content.invisioncic.com/y282845/emoticons/fro.gif.c695f1f814b01c4ad99fe7f8cccadd29.gif

 

[newusername 10+ year member]

You can calculate it empircally by subtracting "actual impedance" - "nominal impedance".
Remember,, impedance is resistance at a given frequency (from what I understand)

It would seem the value would be understanding how to calculate it in advance.

Problem is...I think heat would build up to skew the value. As the coil got hotter, that would also change the impedance.

I think this is correct. Fortunately, there will be somone to correct my answer.

You've got the gist of it. Impedance describes the opposition to alternating current, which differs from the DC resistance often measured in a speaker. Both tend to increase as the coil gets hotter, but impedance varies with frequency. The published "nominal impedance" (ie. DVC 4 ohm, DVC 2 ohm, etc.) is usally just the rounded up value of the DC resistance. Impedance describes the magnitude of voltage, current, and the relative phase.

 

[Flipx99 5,000+ posts]

Then it should be able to be modeled so that one could predict actual impedance in advance to maximize the effectiveness of the amplifier. Voltage and current can be controlled as inputs.

Is the box what affects the relative phase of the driver?

 

[tommyk90 5,000+ posts]

Then it should be able to be modeled so that one could predict actual impedance in advance to maximize the effectiveness of the amplifier. Voltage and current can be controlled as inputs.
Is the box what affects the relative phase of the driver?

We all know how well calculations on paper translate into vehicles now don't we? //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

Too many other factors are involved for a person to ACCURATELY predict impedence rise in a given environment. Coil temperature, ambient air temperature (which can play with the air pressure in the cabin), voltage drop (which affects efficiency among other factors), the sub itself (suspension stiffness, coil material, etc.). Well, you see where I'm going with this. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

The only way to accurately determine impedence rise (and be able to control/change it) is to test, test, test. Then when you are done testing, test some more.

//content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[Flipx99 5,000+ posts]

We all know how well calculations on paper translate into vehicles now don't we? //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif
Too many other factors are involved for a person to ACCURATELY predict impedence rise in a given environment. Coil temperature, ambient air temperature (which can play with the air pressure in the cabin), voltage drop (which affects efficiency among other factors), the sub itself (suspension stiffness, coil material, etc.). Well, you see where I'm going with this. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

The only way to accurately determine impedence rise (and be able to control/change it) is to test, test, test. Then when you are done testing, test some more.

//content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

So the vehicle still plays a part. I am always trying to reduce the variables I guess. I would figure this would seem more mathematical in nature. As we can control current and voltage, measure coil temp, etc. What I can't measure (and I am emphasizing i) can't test is how this plays out in a vehicle.

I see where you are going with it. I assume those who do the test, test, test don't really publish their findings. Or atleast publish them in a comprehensive way, like in academic settings. It seems you could build a model (in my mind, anyway) but it would be so specific that it would be worthless.

Thanks for reminding me I can't model my way out of testing. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[tommyk90 5,000+ posts]

So the vehicle still plays a part. I am always trying to reduce the variables I guess. I would figure this would seem more mathematical in nature. As we can control current and voltage, measure coil temp, etc. What I can't measure (and I am emphasizing i) can't test is how this plays out in a vehicle.
I see where you are going with it. I assume those who do the test, test, test don't really publish their findings. Or atleast publish them in a comprehensive way, like in academic settings. It seems you could build a model (in my mind, anyway) but it would be so specific that it would be worthless.

Thanks for reminding me I can't model my way out of testing. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

Most people don't post their findings because in reality its not going to really help anybody else out.

All cars are different and are going to react differently. Thus why you can take a box from a CRX that does 155's, drop it into another CRX and only do a 150. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

The vehicle plays a VERY significant part. Just as important as the equipment and box itself.

 

[Chevyaudio 5,000+ posts]

Mine's stronger....
nG

Sure thing buddy. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

 

[ngsm13 5,000+ posts]

Sure thing buddy. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

Don't think so?

nG

 

[Qbenjamin 10+ year member]

//content.invisioncic.com/y282845/emoticons/wow.gif.23d729408e9177caa2a0ed6a2ba6588e.gif I wish you all would start speaking some ENGLISH......//content.invisioncic.com/y282845/emoticons/crap.gif.7f4dd41e3e9b23fbd170a1ee6f65cecc.gif

 

[lilmaniac2 5,000+ posts]

eh?

 

[sundownz Pro Seller]

Got a preliminary 12v power test:

Alrighty... so I abused the infamous Pyramid power supply a bit more today. Same setup I've been using for other clamp tests:

Pyramid 50 Amp Power Supply

8 AWG from supply to batteries

Kinetik 2400 Battery

Duralast 1000 CA Battery

2 AWG between batteries

4 AWG from batteries to amp

Fluke AC current / voltage meter

Sears DMM

Measurements:

65.8 volts

49.2 Amps

1.33 ohm calculated rise from 0.6 ohm DCR **

3237 Watts

14.4 volts rest dropping to 10.75 volts

** - Rise was higher than when I tested the 1500D, it was 1.08 ohms for that test. Presumably since my single run of 12 AWG speaker wire is heating up some much due to the extra power. I also did a few test runs at lower volume so the coils were warmer as well.

I really need a much more powerful power supply for this test. Pretty well simulates a stock Honda alternator or something, though!

I didn't try to push for more volume on the test HU... I may do that later, but the voltage drop was getting so bad I didn't want to damage the amp from under-voltage. If I can dig up some more ring terminals I might do it with another battery to see if I can hold at least 11.5 volts.

 

[ngsm13 5,000+ posts]

Got a preliminary 12v power test:
Alrighty... so I abused the infamous Pyramid power supply a bit more today. Same setup I've been using for other clamp tests:

Pyramid 50 Amp Power Supply

8 AWG from supply to batteries

Kinetik 2400 Battery

Duralast 1000 CA Battery

2 AWG between batteries

4 AWG from batteries to amp

Fluke AC current / voltage meter

Sears DMM

Measurements:

65.8 volts

49.2 Amps

1.33 ohm calculated rise from 0.6 ohm DCR **

3237 Watts

14.4 volts rest dropping to 10.75 volts

** - Rise was higher than when I tested the 1500D, it was 1.08 ohms for that test. Presumably since my single run of 12 AWG speaker wire is heating up some much due to the extra power. I also did a few test runs at lower volume so the coils were warmer as well.

I really need a much more powerful power supply for this test. Pretty well simulates a stock Honda alternator or something, though!

I didn't try to push for more volume on the test HU... I may do that later, but the voltage drop was getting so bad I didn't want to damage the amp from under-voltage. If I can dig up some more ring terminals I might do it with another battery to see if I can hold at least 11.5 volts.

We got some huge power supplies at my shop, can parallel them even.

I need to get with you via email I guess Jake...

nG