Quick help on gain settings

[RoachForLife 10+ year member]

Hey all, finally got my subs fixed so readjusting the gain. Getting myself confused so I wanted to run this by everyone.

Setup

Alpine PDX 1.1000 mono amp

2x JL W6v2s (12") - 4ohm DVC

Based on my my reading here is what im calculating

2x 4ohm subs = 4ohm at amp

4ohm x 1000w = 4000

sqrt of 4000 = 64

I grabbed a 50hz test tone, unplugged my front speakers and sub, turned HU to 3/4 volume, and im on V~ to the sub amp. I need to adjust gain until at 64 right?

I ask because I thought last time I did this I lowered it to like 45 but I just did this above now and its at 80 so its just confusing. Either ive been running more power for some time, or im calculating wrong.

Also Im not sure if Im doing the ohms correctly. The JL tutorial says something about 2x it, etc Also worth noting that the PDX amp has 2 inputs but since its a mono amp I believe it just bridges it together internally so I dont have to do it from sub to sub. Just FYI

Thanks all!

Click to read more...

 

[plantinseeds]

You want a reading of 36.1 volts on the AC setting on your DMM. Make sure to set your range so you are able to get a 36.1 reading and not 3.61.

Here's a simple calculator to use instead of doing the math yourself Wattage

EDIT: Sorry you want a 31.6 Volt reading not 36.1!

 

[RoachForLife 10+ year member]

Hmm, the thing that Im unsure of is how the amp bridges this. My subs are not wired to one another. I do have it so that on a single sub, one - goes to one +. The unused - and + go to one of the ports on my amp (- and + respectively)

I do this for both subs.

With this said, since its a mono amp (not a 2chan) it would seem to me that internal to the amp it is bridging the 2 'connections' to make 1. Im not sure how this results in the end. With the calc you posted, if I select parallel/parallel it shows 64, if i do series/parallel it shows 32

Thanks

 

[plantinseeds]

Just ignore the other set of positive and negative terminals on the amp. Take the positive from one sub and the positive from the other sub and splice them together, take the negatives and do the same thing. You should get a 1 ohm load on your DMM if you have everything wired in parallel. From there just stick them in one set of positive and negative terminals on the amp.

Subwoofer Wiring Diagrams, Two 4 ohm Dual Voice Coil (DVC) Speakers

and on the voltage calculator you should choose the "Parallel" option where it says Wiring Configuration, it should tell you 31.6 volts at 1 ohm if you did it right.

There's a simple diagram on how to wire two DVC 4ohm subs to a monoblock.

EDIT: Or you can take the two positives from the subwoofers and put them into the two positives of the amp, and do the same with the negatives. The amp just automatically bridges the 2 ohm loads together and creates a 1 ohm load.

 

[plantinseeds]

Hmm, the thing that Im unsure of is how the amp bridges this. My subs are not wired to one another. I do have it so that on a single sub, one - goes to one +. The unused - and + go to one of the ports on my amp (- and + respectively)
I do this for both subs.

With this said, since its a mono amp (not a 2chan) it would seem to me that internal to the amp it is bridging the 2 'connections' to make 1. Im not sure how this results in the end. With the calc you posted, if I select parallel/parallel it shows 64, if i do series/parallel it shows 32

Thanks

BTW best place to post questions like these, is in the Help 101 section.

 

[RoachForLife 10+ year member]

my amp doesnt do 1ohm. I plan to keep my 2 4ohm DVC subs at 4ohm to the amp

 

[plantinseeds]

Oh yeah, 63.2 Volts then. Sorry should've read up on the amp before posting! Make sure you are getting a 4 ohm load from your speakers before you hook them up to your amp. (Obviously)