posted
I had talked to DJ at AudioQue about this sometime last year but we both are unaware if this theory of mine is true so let me lay it out-
I have now 2 Audioque HD15s, Dual 1.4 ohm.
Let's just take one for this example- 1 of those wired in parallel is 0.7 ohms.
The AQ HD15 is rated at 1000wrms. That's about 27V and 37A would equal 1000w at 0.7 ohms meaning the windings inside can handle 37A constantly.
Ok, now onto this-
The JBL amps can output there power at multiple ohm loads without power fluctuation like other amps starting at 4ohms or close to it.
the interesting thing about these amps is the output specs. When metered, the voltage is sky high whereas the amperage is pretty low!
For example - 2400w output would be 130v and 16A because these amps from what i've been told meter at an 8ohm load.
IF it can do 2400w of power with only 16A output, that means the sub can handle 4,800w, 1 amp per coil and still be ok wire winding wise...
Now, let's go to the resistance rise- 1 amp per coil, wired at 1.4 per coil. A 30 - 40 band EQ setup to cut the frequencies down where resistance rise is under 4 ohms so it doesnt cause problems with the amps. Now, after that is accomplished, the only thing left is being able to control excursion-
By building a box for this sub and preventing it from moving too much, too much as in over-excursion.........
Would this mean that the AQ sub, for example, could handle a REAL 4,800w consistently without any problems that would lead to failure as long as the above methods were properly carried out and worked?
quote:Originally posted by shizzzon: IF it can do 2400w of power with only 16A output, that means the sub can handle 4,800w, 1 amp per coil and still be ok wire winding wise...
how do you figure...
--------------------
quote:it would all be for nothing without my favorite cawk-smoker NAvi
posted
well, thicker wire means it can handle more amperage...
IF your amp is running at 8 ohms, 16A output times 8 equals - 128V. 128x16 = 2048w (for example).
JUST FOR THE SAKE of the wire inside and out, it would\should be able to take twice that amount, which for this example would be 4,096w which would equal 256v and 32A of current. 32A is not a lot when comparing it to over 4,000w of power.
This is just for the life of the wire, the wire should\would not burn, melt or catch fire. That's the point i am makin about the Amperage issue.
posted
Basic electronics tells you that when your voltage goes up so does your current draw. When the amp has a higher voltage applied, it will produce more power thus drawing more current. It does not have a threshold of power that it "wants" to produce so it ups the voltage and lowers the current. That goes against all laws pertaining to electronics. It would be nice, but it is not the way things work. There are two formulas that will show you that your assumptions are incorrect. For instance: v squared / R So, your amp puts out 1kw at .7 ohms. This does mean that 27v and 37amps would produce 1kw. Now, to produce 2400w, the amp would put out 41 volts and 58 amps would be drawn. That is the way it works. There is no way to change it.
The limiting factor is not the exact voltage and then vary the amps or vice versa...Your limitation lies in the diameter of wire and the diameter of the voice coil alone! 4800 watts rms into a standard 3" or 4" voice coil is going to burn the windings over time...
A couple of things to think about! The LARGEST guage wire I use on a voice coil is 16 guage and the smallest I have used is 26 guage...I HIGHLY doubt anyone is using larger than a 16 guage wire (I use that on my .35 ohm voice coils) so do the math, 16 guage solid wire (you pick copper or aluminum) and figure it at somewhere between 60-120 feet long (average length used on voice coils) and explain how it can handle 4800 watts rms...Now, compound the fact that when you wrap 4-8 layers of wire on top of each other you are losing heat dissapation and that will further reduce the amount of continuous power the wire can handle...
Now, impedance rise...remember, there are multiple factors there as well! Your ac inductance is going to vary from unit to unit depending on impedance and winding length so saying that calculating rise on one impedance would even begin to cover as a blanket rating is far from the truth...keep in mind a lower impedance coil will use a larger guage of wire and thus have few wraps of wire to achieve the desired winding length...also keep in mind that this is one of the huge advantages of flat wire coils...1/3 - 1/6 as many wraps of wire on an equal impedance round wire coil so many people overlook this but it makes a HUGE difference on impedance rise...
I don't have a chart in front of me and I won't pretend to have it memorized, but 120 feet of 16 guage wire handling 4800 watts continuous isn't being realistic! Use this to help with perspective...Think of a home electrical system...now picture trying to pull 43 amps and 110 volts through 120 feet of 16 guage wire and claiming it can handle it all day (rms)! Oh, and unless this amplifier is just amazing beyond believe there will be some dc thrown in the mix of that as well so don't forget to calculate a little dc heat as well!
-------------------- Now, LEAVE ME ALONE... "Bigfoot, a figment of someone's imagination, or a mythical creature that is only seen in Ohio" has spoken!
my real email addy is shocker_mike@yahoo.com but wayne don't allow yahoo accounts so my account is working off of a dead email! Posts: 1757 | From: sherwood | Registered: Jul 1999
| IP: Logged |
posted
so with flatwire, there will be less AC flux-density caused inductance. Does that reduce the need for shorting rings on the x- as well...which should help keep the BL up by having a smaller copper ring or none at all? and still maintaining a fairly balanced inductance curve? of course i understand that pole design will play in as well.
-------------------- World Record-Loudest SPL in my driveway Team Powermaster/XS-Power Hifonics Amps, Kicker subs-The way it should be Zensky....World Domination at It's Finest www.zensky.com Posts: 2941 | From: Columbus, OH - formerly FL | Registered: Oct 2003
| IP: Logged |
![[Big Grin]](biggrin.gif)
![[Eek!]](eek.gif)
Printer-friendly view of this topic