DiyMobileAudio.com Car Stereo Forum banner
1 - 20 of 139 Posts

·
Registered
1999 Jeep Wrangler TJ
Joined
·
334 Posts
Discussion Starter · #1 · (Edited)
Here's my situation:

I have an NVX VCW104v2



  • 10" Dual 4-ohm VC-Series Car Subwoofer
  • Power Handling:
    • Peak: 1500 watts watts
    • RMS: 750 watts watts
  • Recommended Power Range: 600 - 750 watts watts RMS
  • Impedance: Dual 4 ohm
  • Pressed paper cone with woven fiber top
  • Custom High Roll Foam Surround with Nylon Stitching
  • Heavy Duty Die Cast aluminum basket for maximum rigidity
  • Dual Poly-Cotton Spiders
  • 2.5" High Temperature Aluminum Voice coil
  • 127oz. Triple stacked Ferrite magnet motor structure with protective rubber boot
  • Frequency response: 20-200 Hz
  • Resonance Frequency (Fs): 29 Hz
  • Optimal sealed box volume .70 cubic feet
  • Optimal ported box volume: 1.50 cubic feet
  • Top-mount depth: 6"
  • Sensitivity: 83dB

I have this powered by the NVX VAD10001



  • Peak Power Rating: 2000 Watts
  • RMS Power Rating:
    • 4 ohms: 420 watts x 1 chan.
    • 2 ohms: 760 watts x 1 chan.
    • 1 ohm: 1000 watts x 1 chan.
  • LED power (blue) and protect (red) indicators
  • Conformal Coated Marine grade circuit board
  • Heavy duty aluminum alloy heat-sink
  • Platinum-plated RCA level inputs
  • Platinum-plated screw terminals
  • Preamp RCA outputs to daisy chain multiple amps
  • 3-way protection circuitry (thermal, overload, and speaker short protection)
  • Variable subsonic filter: 10 - 55 Hz, 12 dB/octave
  • Variable low-pass filter: 50 - 250 Hz, 12 dB/octave
  • Bass Boost: 0 - +12dB boost @ 45Hz
  • Input Sensitivity: 200mV-6V
  • Total Harmonic Distortion: <0.3%
  • Fuse Rating: 30A x 3
  • Phase: 0-180 Degree Switch
  • Power Wire Gauge: 4 AWG
  • Speaker Wire Gauge: 8 AWG


It's wired at 2-ohm. 4 gauge wiring kit. The only thing I see I'm mismatching is that it recommends 8 gauge speaker wire but i'm using 12 gauge at the moment.

I've read dozens of threads on sub amp tuning, but I'm still not feeling this is right.

So, the sub handles 800 w RMS. The tech at NVX confirmed this. The amp is rated at 760 w RMS at 2 ohm, but the NVX tech said it dynos between 800 and 900.

I noticed when I turn it up enough to feel it (not crazy, I'm not a bass head, but I like to at least feel the bass) the sub makes a slapping sound on the slightly higher bass notes. At this point the gain is turned up maybe a quarter. I don't have bass boost, nothing pushing that through my HU, DSP, or on-amp controls.

I tested the input voltage at the amp, coming through at 13.9 with the Jeep at idle, no matter how much bass is playing.

It doesn't seem right that I should get so little bass through this setup. I've had 300 w RMS sub and amps that hit harder than this.

Anyone have any ideas?
 

·
Registered
Joined
·
8,850 Posts
what box is it in? What is the LP filter set to? Are you using the SSF? How did you set the gain?
 
  • Like
Reactions: Jheitt142

·
Registered
Joined
·
455 Posts
that sounds like over excursion to me. i don't remember if you've moved to the dual sub box yet? if you're using a dual box with just the one sub that's probably where it is all going wrong
 

·
Registered
1999 Jeep Wrangler TJ
Joined
·
334 Posts
Discussion Starter · #4 ·
what box is it in? What is the LP filter set to? Are you using the SSF? How did you set the gain?
Oops, didn't post that.

Sealed box, .80 cu ft. Amazon.com: Single 10" Subwoofer Regular Standard Cab Truck Sub Box Enclosure 5/8" MDF : Electronics Nothing fancy, but it matches the ratings for the sub. Though that doesn't take into account displacement... hmm.

LP is set to 23.5 on my DSP.

I'm not familiar with SSF.

I turned on a bass heavy song, turned my DSP's sub output to high, volume to 3/4s, increased gain until I heard anomalies, in this case the slap.
 

·
Registered
1999 Jeep Wrangler TJ
Joined
·
334 Posts
Discussion Starter · #5 ·
that sounds like over excursion to me. i don't remember if you've moved to the dual sub box yet? if you're using a dual box with just the one sub that's probably where it is all going wrong
Not yet, though that's in the works. I have a guy at my work who builds sub boxes and I'm getting a price quote on a ported box for this sub. Just to see my options.
 

·
Registered
Joined
·
455 Posts
i'm at work so no WINISD with me. but it sounds like over excursion. which probably shouldn't be an issue with a well set LP. But what that setting looks like is up to WINISD more then guessing. the hard parts should just wail in your jeep. So i'm going to the say the box is the problem assuming theres no funky EQ action going on anywhere
 

·
Registered
1999 Jeep Wrangler TJ
Joined
·
334 Posts
Discussion Starter · #7 ·
i'm at work so no WINISD with me. but it sounds like over excursion. which probably shouldn't be an issue with a well set LP. But what that setting looks like is up to WINISD more then guessing. the hard parts should just wail in your jeep. So i'm going to the say the box is the problem assuming theres no funky EQ action going on anywhere
I've tried WINISD and I can't make heads or tails of it. If you wouldn't mind throwing some numbers into it when you get a chance I would appreciate it, though no pressure.

Yeah, I worried it might be the box. Finding one that fits a Jeep isn't exactly straightforward.

No crazy EQ stuff. I tried a little bump at 180 Hz to address a null spot, but it didn't work so I cleared it. The only thing I have at the moment is a cut in the, uhhhh, 6k range, I think?
 

·
Registered
Joined
·
8,850 Posts
LP filter for the sub should never be set to 23. Set it to 80hz, and leave t he SSF OFF.
 

·
Registered
1999 Jeep Wrangler TJ
Joined
·
334 Posts
Discussion Starter · #9 ·
LP filter for the sub should never be set to 23. Set it to 80hz, and leave t he SSF OFF.
Oh, I'm sorry, I was confused.

LPF is 80 Hz, SSF is at 23.5. So turn that one off?
 

·
Registered
Joined
·
408 Posts
Dont use the SSF with a Sealed Sub box... its used for Ported boxes.....
 

·
Registered
1999 Jeep Wrangler TJ
Joined
·
334 Posts
Discussion Starter · #12 ·
So does clipping cause over excursion? Or is that box design?
 

·
Registered
1999 Jeep Wrangler TJ
Joined
·
334 Posts
Discussion Starter · #13 ·
I'll turn the SSF off in a bit. Only negative to my DSP is no smart phone integration
 

·
Registered
Joined
·
2,740 Posts
The gain at a quarter may be too high, unless you have looked and set the gain with a scope it could very well be clipping and pushing the sub past it’s nice limit… clipping is just extra power into the sub by making more area under the sine wave, more power can potentially drive the sub into over excursion

whether or not your a bass head doesn’t matter, we have no way of knowing your expectations, what I call a healthy bass end might be more than most or less, it’s relative
 

·
Registered
2021 Chevrolet Silverado Trail Boss Crew Cab
Joined
·
2,043 Posts
Have you taken any measurements? You could have a frequency or two that are running higher than the rest and hiting clipping too soon because of it. You may just not have the right sound curve fir your sub giving you too much at one end vs the other of the subs frequency range. I know this was my issue with my current setup.
 

·
Registered
1999 Jeep Wrangler TJ
Joined
·
334 Posts
Discussion Starter · #16 ·
The gain at a quarter may be too high, unless you have looked and set the gain with a scope it could very well be clipping and pushing the sub past it’s nice limit… clipping is just extra power into the sub by making more area under the sine wave, more power can potentially drive the sub into over excursion

whether or not your a bass head doesn’t matter, we have no way of knowing your expectations, what I call a healthy bass end might be more than most or less, it’s relative
Is there any way to tell without an oscilloscope? That's on my list of upcoming purchases, but just not right this second (cost).

I do like a healthy level of bass, just not to the point of overwhelming the song. Strong bass, love the chest hit, but the song owns the bass, not the other way around.
 

·
Registered
1999 Jeep Wrangler TJ
Joined
·
334 Posts
Discussion Starter · #17 ·
Light Font Screenshot Slope Audio equipment
Have you taken any measurements? You could have a frequency or two that are running higher than the rest and hiting clipping too soon because of it. You may just not have the right sound curve fir your sub giving you too much at one end vs the other of the subs frequency range. I know this was my issue with my current setup.
Hmm. I've taken several full cab measurements. Do you just mean that or should I be taking measurements close to the sub?

This is since my last set of changes. Two lines are basically identical, just one is windows out, the other windows in. No crazy peaks that I notice.
 

·
Registered
2005 Pontiac GTO
Joined
·
287 Posts
I notice with my setup, the bass really doesn't 'hit' me until I set the TA up correctly. Most likely due to phasing between my mid bass and sub bass.

Have you set the time alignment up yet?
 

·
Registered
2005 Pontiac GTO
Joined
·
287 Posts
View attachment 313483

Hmm. I've taken several full cab measurements. Do you just mean that or should I be taking measurements close to the sub?

This is since my last set of changes. Two lines are basically identical, just one is windows out, the other windows in. No crazy peaks that I notice.
If that were my curve, I'd be looking to flatten out that area from 80/100Hz down ...

Here's my curve before EQ'ing

Rectangle Product Slope Plot Font


And this was after EQ'ing, just using the GEQ in my 80PRS (before I got my Helix DSP)

Rectangle Slope Plot Font Line


Flattening out the lower range, and then boosting the sub level, gives a better curve while maintaining the low end bump when compared to the mid bass/mid range.
 

·
Registered
1999 Jeep Wrangler TJ
Joined
·
334 Posts
Discussion Starter · #20 ·
I notice with my setup, the bass really doesn't 'hit' me until I set the TA up correctly. Most likely due to phasing between my mid bass and sub bass.

Have you set the time alignment up yet?
Heya! TA is set up. Using measuring tape from driver to the center of my head. Though I have a suspicion that I may be off a few inches.

Interesting, I hadn't thought of flattening that curve. I could certainly try that. It doesn't feel like the sour notes (so to speak) with the sub happen in the lowest ranges, but in the higher ranges of what the sub is trying to play. The "higher" sub-bass notes.

I have a guy at work telling me that it's due to not having a ported box and that the only way to resolve this is to have one made. Not sure how accurate this is, but I'm starting to wonder if I should look into a downward firing sub box with a front-facing port made for my Jeep.
 
1 - 20 of 139 Posts
Top