Frustrating

jgs07 · Post by **jgs07** » Wed Mar 25, 2009 3:49 am

i know ive posted in the past of problems with setting my gain but im still having problems and its getting frustrating. i have no idea what im doing wrong.
i set everything on my head unit to zero and everything on my amp is turned down. played a 50 hz tone with my volume at about 3/4(26/35), disconnected the positive speaker wire, inserted one of the ends of my dmm into the positive speaker terminal then inserted the other one into the negative speaker terminal. it read 0.4 without me turning the gain up. then i slowly turned the gain up and the voltage rose little by little. i ended up turning it up all the way and the dmm read 27.4. the problem is though from my calculations, that the gain has to be set at 40.

amp:hifonics bxi 1606d( 1600 watts rms)
subs:2 12" kicker cvrs(4ohm but wired at 1 ohm)
head unit:alpine cda 9884(2v preouts)

my calculations: 1600(rms watts of amp)x1(speaker ohms)=40
:help:

Bwcad1 · Post by **Bwcad1** » Wed Mar 25, 2009 4:01 am

Do no disconnect the speaker leads. Leave them in the amp. I don't know where people are getting this information from but that shit is wrong. Without a load on the amp your not going to see much voltage at all. Reconnect your positive wire and remeasure. ive done this hundreds of times if not thousands, to gain match and set amps.

falkenbd · Post by **falkenbd** » Wed Mar 25, 2009 7:26 am

on subs you can definitely leave them hooked up and play a test tone in short bursts...

falkenbd · Post by **falkenbd** » Wed Mar 25, 2009 7:27 am

oh and try turned the head unit volume up a little bit higher than 75%

I'd say 85-90% of full volume

Bwcad1 · Post by **Bwcad1** » Wed Mar 25, 2009 7:33 am

Even with normal speakers y would you unhook them? that would throw off your measurement because your no longer using your DCR.

falkenbd · Post by **falkenbd** » Wed Mar 25, 2009 9:01 am

some people use a dummy load so they don't blow tweeters.

i think as long as you are careful about what tones you play on what speakers you'd be fine.

for example,
I don't think i'd want to play a 60 hz test tone to set gains on my midbasses.
if you were to play a 5khz test tone to ribbon tweeters i think it could be fatal.

Bwcad1 · Post by **Bwcad1** » Wed Mar 25, 2009 9:20 am

Of course not. I have a hard time remembering that some people are handicapped

lol

Then again if your crossovers were set correctly you would be ok.

jgs07 · Post by **jgs07** » Thu Mar 26, 2009 2:14 pm

Bwcad1 wrote:Do no disconnect the speaker leads. Leave them in the amp. I don't know where people are getting this information from but that shit is wrong. Without a load on the amp your not going to see much voltage at all. Reconnect your positive wire and remeasure. ive done this hundreds of times if not thousands, to gain match and set amps.

i got that info from a write up on here on how to set the gains.
http://www.caraudiocentral.net/forums/s ... php?t=7686
i did what u told me to do bill and its the same thing. except this time when i inserted the leads of the dmm into the speaker terminals the dmm read 0.09 before i started to raise the gain. i turned it all the way and i still did not reach the voltage i needed. i even unscrewed the speakers a lil and stuck in the dmm lead in there and tightend the screw so the lead of the dmm would not get loose and fall out.

Bwcad1 · Post by **Bwcad1** » Thu Mar 26, 2009 2:41 pm

The problem is impedance rise... and y i find that using a DMM to set your gains is not close to being correct... Most of the time your impedance rise is close to 3 times that of your normal dcr. I bet with a normal box your DCR is actually 3ohm or more which actually makes your voltage output much lower than calculated

jgs07 · Post by **jgs07** » Thu Mar 26, 2009 2:45 pm

so what do i do?