99Eternal

Hi there,

I am fairly new to car audio and am in need of some expert advice/troubleshooting.

I'm in the process of upgrading my system, currently I run:

- Headunit - JVC Arsenal KD-A625 running 2.5v pre-amp stinger rca's to amp.
- Door Speakers - Kicker KS600 Coaxials, not amped just running off head-unit's 20w RMS.
- Subwoofer - Infinity Kappa 122.7 4 ohm dual voice coil (hardwired to 4ohm) 12 inch 350w RMS in a ported bassworx box (not sure if this is a proper box for this specific sub or not, bought at futureshop so likely not).
- Amp - Rockford fosgate Prime R1000-1D running 500RMS @ 4ohms to the Kappa.

Now, the good stuff.

The main area of concern is the bass. I want to be able to hear it from a good distance away (a block or so) and I want it to play a wider range of bass than it currently does, right now it seems like it hits decently on a certain low freq and a certain high freq, but hardly hits on anything in between. The result is some songs with low, monotone bass sound good. but most songs - songs with mid-low bass with a range of frequency, sound like monotone and parts hit hard while other parts hardly hit at all.


I WAS running this sub off a Rockford p300-1 which was only feeding it 150rms, so I figured I should upgrade the amp. I was quite surprised that the new Rockford R1000-1D, feeding 500rms to the 4 ohm load, made NO noticeable difference. I was very surprised to have to crank the gain and punch to even hear the sub. I made sure my polarities are correct, connections snug, my ground is only 12 inches bolted directly to the chassis. After hours of tuning this new amp and my head-unit settings, it only hits a tad harder than it did the the p300-1 amp, with no change in range of sound.

Am I wrong, or should that upgrade of amp made a difference?
Is it possible that this sub was actually maxed out with the old amp (I dont see how this could be seeing as I had to turn the gain to max, if anything set higher than the OLD amp) on the new amp. I could understand if the sound was the same with the new amp due to the sub being at it's max, but having to crank the gain to get just the same sound I had before makes no sense to me.

I thought I'd have to baby the gain and punch EQ to avoid over-powering this 350RMS sub (granted, the sub can apparently handle alot higher RMS and doesn't blow easily)


I just really want to make sure I know for sure what is limiting me now before I drop cash on some JL 12w3's or something of higher quality/rms rating than the Kappa.

Having to crank the gain on this new amp just sent chills through my body lol..not a good feeling, not what I expected. Hopefully there is an easy explanation for this.


I really appreciate any help you can offer.

unknown123

http://a248.e.akamai.net/pix.crutchf...4-ohm_mono.jpg

You said you wired a dual 4 ohm sub to 4 ohms? Thats wrong, ur have to wire it to 2 ohms,

Also, Welcome to the forums!!!

99Eternal

Hrmm, ok. Thanks for the response man. Just to make sure we're on the same page its not 2 subs just a single DVC with a selectable impedance switch of 1 or 4 ohm.

Now I am confused, because that crutchfield diagram does seem to show a 2ohm connection, yet the sub has a selector switch of 1 or 4 ohms (this is not an aftermarket switch, came attached to the sub and its in the manual etc.

That could be the issue all along, that would mean I was in fact running this sub at 300rms (closer to 350, that rockford amp is underrated I can't remember the birthsheet but it was 320-350rms). Which would explain why the new amp isn't making much difference.

But that still leaves an issue. if the final impedance is in fact 2ohms although that would explain the overall output/sound of the sub not changing with the new amp, I still don't understand why I am having to max my gain to hear the subs. Because if it is in fact a 2 ohm load, there getting 1000rms. It just surprised me to have to crank the gain even if it's a 4ohm load(500rms from amp) and especially if its a 2 ohm load (1000rms from amp).

Could being that much over RMS have that effect of having to crank the gain? I would think you would have to baby the gain.

Appreciate your time.

99Eternal

I was incorrect, it is a dual 2 ohm voice coil sub not a dual 4ohm. So it is a final 4 ohm or 1 ohm impedance depending what the selector is set to.

It is set at 4 ohm right now.

Sorry to waste your time on that one.

Any other ideas as to why this new amp made no real difference?

That is my main question - why going from the p300-1 at 150rms to the R1000-1D at 500rms has made no audible difference, and why am I having to max the gain??

I expected to have to go easy on the gain and bass boost, but both are maxed to acheive the same sound as the p300-1 gave me.
Back to square one heheh.

unknown123

Then its probably the box , usually prefab boxes suck because they use cheap wood and its built with the proper specs of the sub,

The only suggestion i have is that you build a new box Its fun, trust me

99Eternal

Alrighty. And that is what alot of others say, but I still havn't got an answer for ym main concern. Which is why the gain has to be maxed and bass boost maxed with the new amp. I am having the set the gain and boost the same or higher on the 500rms amp than i was on the 150rms amp.

With all due respect, I don't want to start building enclosures and switching subs until I get this main question answered, because I do understand a poor box will effect the sound, but don't understand why I'm having maxing the gain settings on an amp 3x as powerful as my last. This new amp maxed out doesn't push the sub any harder than the old amp at 3/4 gain and boost.

Hopefully I am being clear enough. I need someone to say, "no, you should not have to max the gain and boost on the new amp to push the sub the same as the old amp did" or "yes, it is expected to have to max the new amp's gain even though it is much more powerful because such and such reasons".

Before I start modifying, I need to understand. That is the mistake I have made up to now, trying new things without thinking/troubleshooting, which leads to alot of wasted money time and effort, and a crappy sounding system. (I am sure you are right, a better box would help alot) but I need to understand why I am having to max my gain before I move onto the box.

unknown123

wait did you change any settings on the deck?

99Eternal

When I installed the new amp, nothing was changed on the head-unit or elsewhere. I ran the connections to the amp, powered it up, and went straight to adjusting the amp setting with the same head-unit settings as before. I was careful to not make any changes besides installing the new amp because I wanted to hear the difference.

I did change head-unit settings AFTER an hour+ of failing to acheive the desired improvement playing with the gain, bass boost and frequency settings on the amp. Went through everything on the head-unit to re-tune, thinking maybe the new amp needed different settings, but the result was the same sound as before with the old amp.

So I am fairly certain it's not a head-unit setting.

Dukk

What car and how is your box situated in it?

99Eternal

2008 Chevy Cobalt LS Coupe.

The box is on my rear seat at the moment facing the front of the vehicle.

It was in the trunk before but wasn't loud enough and the vibrations overpowered the bass. (I know, I'll need to eventually fix the trunk with sound deadening etc. But I won't be doing that until I get the sub in the vacinity of sound volume and quality that I'm looking for)

Planning on moving it to the trunk eventually once I get the power I want from it (or from new subs if that is the problem).