[amit_mechengg]

gurus, i think i have landed up in connecting the GT5-12" sub incorrectly.
the installer had told me that the gt5-12" sub has red and black marking below it. but he said its the reverse way than the other subs. we have to connect the positive to the black and negative to the red.
please help me from this confusion. also where can i get the wiring diagram of the sub?

[Sam Kapasi]

This stands true in the case of the JBL professional drivers where red is negative. Old horses like Navin can confirm.

The GT5-12 is pretty standard. Red is positive. What wiring diagram do you want?

[amit_mechengg]

Originally Posted by Sam Kapasi

This stands true in the case of the JBL professional drivers where red is negative. Old horses like Navin can confirm.

The GT5-12 is pretty standard. Red is positive. What wiring diagram do you want?

sam sir, the installer told me that the red is negative and black is positive. there are two dots on the bottom. i aksed him why is he connecting the positive to the black. he said in case of jbl its "ulta". i drove home the same way.
but i had to carry luggage so i removed the sub box. and now i forgot the positive and negative.
navin sir please confirm what is positive and what is negative.

[JayD]

I don't think its 'ulta',atleast i think my sub is wired in the normal way! Anyways, u do have a 'reverse' mode for the sub in the H.U right??

[amit_mechengg]

got it sir. red is positive. i saw in owners manual. there are two diagrams where they have shown the connections in parallel and series. over that they have written that red is positive. and black is negative.
sam however i found one more thing in the manual. it says that GT5 should be put in small sealed boxes for SQ and ported for SPL. how will it perform in a ported box similar to jbl bass reflex box? can we seal the port for better SQ ??

[ramie2400]

connect it and check out both the ways.where you feel the loudness is clear and bassy thats the right connection

[amit_mechengg]

Originally Posted by JayD

I don't think its 'ulta',atleast i think my sub is wired in the normal way! Anyways, u do have a 'reverse' mode for the sub in the H.U right??

ya but the connections should always be right. the rev on the HU just changes the way the sub fires IMO.

[low_bass_makker]

Originally Posted by amit_mechengg

ya but the connections should always be right. the rev on the HU just changes the way the sub fires IMO.

Bro what ramie singh said is 100 % correct. If you wire all the red with positive and black with negative then it is correct. But some times the acoustic of the car can play with the sound thats why there is a sub phase change option in the HU with actually changes the red -red and black - black to red-black and black - red.

[navin]

Originally Posted by Sam Kapasi

This stands true in the case of the JBL professional drivers where red is negative. Old horses like Navin can confirm.

not only some Pro (44xx, 4312, etc..) and some compression drivers (24xx, also some commercial JBL L series (100A, 112, 220 etc that used the LE14A, LE15A, LE10H or LE8T) or B series bass bins (B380, B460 that used the 2226, 2235 and 2245 respectively) and many sound reinforcement models (46xx series) were all "reverse wired". I assume this had something to do with the fact the the 1/4" phono plug was used instead of the RCA in those days.

Now will someone tell me why I can remember model numbers from 35 years ago but cant remember what I ate for breakfast a few hours ago).

Originally Posted by amit_mechengg

got it sir. red is positive.

you are right.

[amit_mechengg]

@ Navin sir,
i was really wondering how one can remember those big lists of models.i never remembered what the teacher taught in previous classes

sir one more question please. there is a mono and stereo toggle switch on the JBL 75.4. i have put both the switches on stereo.
what is the purpose of that switch. does the amp work like mono? what effect will i get if i put the front connection switch to stereo on which the rear jbl ovals are connected and if i put the rear connection switch to mono on which the sub are bridged?

[navin]

Originally Posted by amit_mechengg

@ Navin sir,
i was really wondering how one can remember those big lists of models.

there is a mono and stereo toggle switch on the JBL 75.4. what is the purpose of that switch. does the amp work like mono?

I have played with most of those JBL woofers. Sam knows that hence he used my name in his post.

the mono stereo swithc is used when you want to pridge 2 channels to one. however when you do that ensure that a single speaker is wired as a mono and it's impedance is above 4ohms. if the impedance is too low and the amp is in bridged mode the amp will trip.

[amit_mechengg]

Originally Posted by navin

I have played with most of those JBL woofers. Sam knows that hence he used my name in his post.

the mono stereo swithc is used when you want to pridge 2 channels to one. however when you do that ensure that a single speaker is wired as a mono and it's impedance is above 4ohms. if the impedance is too low and the amp is in bridged mode the amp will trip.

in that case since i have bridged the GT5 sub which is just 4 ohms , i should keep the switch on the stereo mode strictly otherwise the amp will trip right?