Derf, can you email me the same two tones, 100Hz and 1KHz?

hghspeed3@hotmail.com

Thanks man.


-Chris

Ah OK. Didnt get tones sent out. I was too bust installing my projector TV and auditioning my new Senn HD590 headphones Needless to say I had a good evening.



Just use that nominal 2ohms then when using the multimeter to set the gain. I may be on aim tonight if you need assistance or have any questions. AIM name is gafugyaself





"all your bass are belong to us"

got the tones, thanks a bunch man.

no wonder i was blowing my voice coils. when i tried it out, i had it sending 45.8 volts, or rather, 928 watts each channel, on an amp thats 650-700 rms. i was clippin the signal like crazy. i guess i'm not meant to set the gains by listening to it.

anyways, i lowered it to 39.1 on each channel. that gives me 697 watts on a 2.2 load. but i have them mono. when i test it using both terminals, i get 78.2 volts, on the 2.2 load i'm providing, thats 2779 watts. and then since i have 2 drivers, thats 1389 watts each. should i hook the multimeter up mono andset the gains like that? i want the gains to be even. i was thinking i should drop the gains to 30 and 30, so mono i get 60, which is 1636 or 818 per speaker. would that be right? or is it fine at 39.1 each channel? am i multiplying sometyhing wrong?

you just need to set one channel. don't use both channels together or anything crazy.


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but i have it bridged mono... if i only set one channel.., arent i only getting power from one channel then? or do i set one channel to zero and set the other one as if it were two?

your setting your gains to match the output signal of your headunit. you only need to use one channel to do that. it has nothing to do with measuring power.


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Just use the multimeter like you would the sub bridged. + of one channel and - of the other and measure. Dont mess with measuring both channels.

How is it that you are getting 2.2 ohms though? You should be rusing the nominal 2ohm impedance if you are doing series/parallel an a pair of dual 2ohm subs. Not always a good idea to run 2ohm on a bridged amp either. Generally they are only 4ohm stable so theres a chance you could send the amp into protection. WIth the gain set properly you shouldnt have a problem if it doesnt go into protect though.






"all your bass are belong to us"

derf wrote:Just use the multimeter like you would the sub bridged. + of one channel and - of the other and measure. Dont mess with measuring both channels.

How is it that you are getting 2.2 ohms though? You should be rusing the nominal 2ohm impedance if you are doing series/parallel an a pair of dual 2ohm subs. Not always a good idea to run 2ohm on a bridged amp either. Generally they are only 4ohm stable so theres a chance you could send the amp into protection. WIth the gain set properly you shouldnt have a problem if it doesnt go into protect though.

it hasnt gone into protect or blown any fuses. it gets real hot sometimes, but never givin me any problems. which gain do i set then? the one from the channel i'm taking the positive from or the one i'm taking the negative from? and what do i do with the other? turn it all the way down? i'll assume i set the gains from the channel i'm getting the + from..

i'm getting 2.2 ohms from the speakers specs. audiopipe.com has the specs of the speaker and it says 2.2. and now i just realized it downt say 2.2, it says 1.8 stupid me. do i use the 1.8 from the site or just round it off to 2?

http://www.audiopipe.com/TXX_specs.asp the TXX-BC-15"

so you have two gains on your amp?


and you should measure the ohms yourself, yours will be different then what they say it is.


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indeed i do



thats why i didnt understand why i'd only use one gain if i'm connecting the speakers to both channels....

i measured theohms at the terminals, they're 1.4 and 1.4 on one speaker and 1.3 and 1.5 on the other. after connecting series then parallel, i get 1.4 again. use that?

yes, you need to set it up to a real world load.

and i guess i would just set one gain, then match the other one to it.


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You can't get the real world load since you can't measure the impedance of the system. You have to use the specified impedance value. You can measure the resistance of the wiring and add that to the rated impedance.

huh? your saying use the 1.8 that on the site and not the 1.4 i just measured? but wysi just told me to do otherwise!

*sigh*

why cant i measure the im[edance of the system? isnt that what i just did with the multimeter?

i think i'm confusing measuring actual power versus setting the gains, dunno why but i forgot exactly what you were doing, lmao.

use the nominal impendance when you set gains.....measure the ohms when you test for power output.


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The RE is the DC resistance not the Nominal Impedance. The Nominal Impedance is 2 ohms per coil. So with series/parallel wiring you should present the amp with a nominal 2ohm load.


As for which gain to use....read your amp's manual on bridging it and see what it says. I believe RF just uses the first gain when bridging.



"all your bass are belong to us"

You cant just measure the resistance of your speaker and get the true impedance.

You understand that your speakers have voice coils, now lets just look at the fact that they are coils.

The Inductive reactance of a coil can be found from the following formula:
X=2pifL
f is frequency in Hz
L is inductance of the coil

With this you now add the resistive component to the impedance (Z)
Z= SQRT(Sqr(X) + Sqr(R))
SQRT sqare root of
Sqr is sqaure of
X as determined above
R as measured with the meter

An easier method of determining the Z of your subwoofer is look at the mfg spec sheet where it states the nominal impedance.

Now if you insist on setting your gain with the volt meter appearant power can be determined from the following equation:
P=Sqr(V)/R make sure that you follow orders of algebraic operations or you will get this wrong.

Measure at the amplifier terminals and ignore the resistance of the wiring from the amp to the subwoofer. To be able to measure this as part of your subwoofer impedance you would need something far more advanced that even the best digital multimeter. For a first engineering approximation, assuming that you have sized the speaker cable correctly, generic conductors are assumed to have a circuit loading of 0Ohms.
The speaker terminal you will place the meter across are the terminal to which your speakers are actually connected to. Adjust both gain pots equal amounts.

Make sure you know the bridged RMS of your amplifier before you start this. Yes RF does underrate their amplifiers, but the spec tells you what the minimum abilities of the amplifier will be when you purchase that particular model. The 'Birth Sheet' tells you what the amplifier demonstrated in preshipping acceptance tests. If you have the birth sheet or can get a copy from RF you may use this. Otherwise use the factory published specs of the model you have. Calculate the max voltage you can have and make sure that no one gain is set to take you above half of this, the two gains together should set you exactly where you want to be.

Ignore the maximum peak power for your calculations, all calculations must be done in RMS since that is where the unit will typically operate. Think of Peak power as the random, "I didn't expect that!" cannon or gun shot that might go to your speaker. If you try to run at peak power, you will blow your sub, again, or brun up the amplifier, possibly both.

i dont have the manual/spec sheet or birthsheet for this amp. i bought it used from a friend. if anyone knows how bridging on this amp works, i'd like to know.

when i tested with the multimeter, it seems that it adds both gains. if i set one channel to 40.o and the other to 40.0, then i checked the bridged terminals and it gave me 80. so if i want to set it at 60, just set both gains equally, i assume. if anyone knows, lemme know

Rockford Fosgate 1000a2

right now i have each channel at 39.1. if anyone knows anything about bridging, lemme know...

You are running at either:

6794 for + to + / - to - coil connection for 0.9 Ohms
or
1698 for +(1) to amp +(bridge mark on amp/ -(1) to +(2)/ -(2) to -(bridge mark on amp)

No wonder you're blowing coils.

I am not sure RF makes any stereo amps that go that high. They make plenty of monos, but I doubt your unit is supposed to go that high. I think that model was designated as 100Wx2. The tested power was probably only 200W for the highest unit shipped.

Let me get some info from my brother, and I will let you know what I get from him

Talked with the Bro. RF only states in the specs that this is 1000W into 4 Ohms. and it is stereo.

OK here is the trick.

To pass preshipping test, this amp has to make 1000W into 4 Ohms on channel 1 and same on channel 2. This is simultaneous.

Your set up if wired for the calculations I made showing 1698 is good to go. All bridgable stereo amps from RF are stable bridged into a 2 Ohm load.

It is discouraged to wire your system for the 6794 into a 1 Ohm. A mono amplifier from them is a different story.

You might be able turn your invidual gains as high as 42V, and still be good.

so i could turn each gain to 42 volts and be alright? when i blew one of the coils, i had it on 46. sincei turned each one down do 39, its been fine(so far..)

if its at 39v, then i'm running 1690 to each sub?(@ 2 ohms bridged)

I missed that you had two DVC-subs wired parallel to eachother.

The coils of each individual sub are series on the sub. Then the pair of subs is wired parallel. I get it now.

Your raw power out of the amplifier is 3397W, and each sub gets 1698W.

Don't push for the 42V, cause it won't even give you 1 dB on your SPL, and if 46V was blowing the coils 42V starts cutting it too close.

3400W on a pair of 10's, you must compete in the hear protection required bracket.

yea, it sounds fine the way it is now at 39. i cant really hear the difference and my mirror is falling off as it is. i hurts my ears to be in my ar for a long time. . they're 15's though, not 10's.

the subs are 850rms, 1700 max. i dont hear any distortion(maybe on a few songs, but very little). if the power is clean, you think its alright where i have it..? should i turn it down further?

If they sound ok where you normally listen check them with a meter again to see they are. My guess is that becasue they are so large, listening you don't use nearly that much power.

Have you ever had your SPL checked. My guess is about 120dB.

That volume might explain your earlier post about not hearing so well.