Ready to pull my hair out

[sodak76 0]

Hi all, longtime lurker, first time poster. I'm not new to car audio, but I am new to this forum. I have an issue with my system setup, basically that there isn't much bass over the factory premium audio system. It's a long post so bear with me.

 

I am trying to get a similar output to the systems I've had in the past but am coming up short. My previous system was in a 2007 Grand Prix. It had a Kenwood Excelon headunit with sub out, two PPI Art series amps (an A300 running the highs @ 2ohms and an A600 bridged to 4ohms to run the subs), the highs were a pair of 6 3/4"s in the front doors and a pair of 6x9s in the rear deck- all the high speakers were Kenwoods, and a pair of Elemental Designs dual 4ohm VC 12s in a sealed box. I tried 2 different models of the eDs, one pair were 13Ov.2s, and the second were 13Kv.2s. The Ov.2s had a bit more output, but otherwise they were pretty close. So basically, this system was completely aftermarket. The output I got using a 50Hz tone was 129dB with the Ov.2s and 126dB with the Kv.2s.

 

Last December I went to a Dodge Charger RT. A very different animal stereo wise. It came with the factory premium Alpine system which has three dash speakers & a speaker in each door in the front, a speaker in each door in the rear, and two speakers and a subwoofer in the read deck. The dash and rear door speakers appear to be 4" or 5", the front door and rear deck speakers are 6x9s, and the sub is a dvc 8" running free-air in the rear deck. All of this is powered by a 500w factory amp, which is fed by what they call a CANbus system from the head unit. Basically it sends a non adjustable signal to the amp along with a separate wire to control the various adjustments (volume, tone, balance & fader, etc.). So adjustments are made by the amp initiated by a control wire from the head unit. I would go completely aftermarket, but the problem with this system is that the radio and heating & A/C controls are integrated together. You can add an aftermarket system, but either it'd have to be standalone or I could pull the factory unit and lose my temperature controls. So this system is going to be adding a pair of subs and an amp to the factory system to get the extra bass it is lacking.

 

To tie into the system, I used a PAC unit that basically T-taps into the CANbus and sends a non-filtered signal over 2 pair of RCAs (front and rear) and a remote turn on for the amp. With this unit the all of the head unit adjustments go through except for tone control (bass, mid, treble).

 

I picked up an Earthquake Mini D 1000 amp to run my subs. It's a class D amp that puts out 180w @ 4ohm, 360w @ 2ohm, and 600w @ 1ohm. The reson I went with it is that the fuse rating is only a 30A, so there would be less chance of dimming headlights.

 

I lost one of my Ov.2s (accident happened and left the cone cracked) so I went with the Kv.2s. These were only going to be temporary as I need a set of free-airs for another project and these will run free-air as well as sealed and ported, according to the manufacturer. The box I built was 3/4" MDF, screwed, glued, & is a sealed enclosure with no dividing chamber since I was going to run a mono amp and a total air space of 2.1 cu. ft. I got eveything hooked up, used the DMM procedure to set the gain of the amp, and went to test it. First I ran into an issue with the 12s being out of phase with the fatory system (turn up the amp's bass control knob and the bass output went down instead of up). To remedy that I flopped the postive and negative wires at the enclosure's terminal cup. That solved one problem in that the bass didn't decrease when I turned up the bass knob. Now the addition of the subs was noticeable, but barely. I tried adding polyfil to see if it would make a difference but could tell any from without it.

 

I was thinking maybe my subs were going or that the car was more insulated than my previous one. So I looked into a pair of SSA DCON 12s in dual 4ohm. Seeing the reviews and talking with Aaron it sounded like they would give me a jump in output over the eDs. So I ordered a pair and after receiving them I installed them in place of the eD subs. While there was a bit lower frequency extension, they run about the same level as the eDs did. Today I decided to test them as I had in my Grand Prix, with a 50Hz tone and my SPL meter. I ended up with 116dB of output.

 

So now I'm looking at a 10dB loss between the two systems. Beings that the eD subs are about the same output (a little lower than the DCONs) that's a pretty big difference.

 

I contacted Earthquake and he was hung up on three things. First that maybe the output signal of the PAC device was too low. Considering I used the DMM procedure to set the gain, that should be the case. I used the suare root of (600w x 1ohm) and come to 24.49V. Using that figure I adjusted the gain on the amp, and at that amount the gain pot is slightly under a 1/4 of the way up. If it was too low a signal I would be closer to the top of the gain pot's range. Second he was sure that the phase issue could also be causing the low output. I agreed, if I hadn't already reversed the leads to the sub enclosure. He was adamant that that would not fix the issue, and that I would need to adjust the phase before the input stage of the amp, not on the output stage. He was also concerned with the suspension of the DCON 12s being too stiff and that the amp would have to work harder just to move them compared to a driver with a looser suspension. But since the eD subs are much looser than the DCONs & I have the same issue with them, I don't think that's the case. He assured me that no one's had any issues with output with this amp, of course I doubt he would say otherwise.

 

I contacted PAC and he agreed with me on the phase issue, that it shouldn't matter if you reverse the signal leads ahead of or after the amp. Since there is no adjustment on their unit itself (no gain or crossover) there wasn't much else he could do, but I figured that it wouldn't hurt to call.

 

So now I still have a 10dB lower output than my previous system, and am running out of ideas. You can feel the bass a little bit, but it's mostly heard. It could be an issue with the class D Earthquake amp not actually putting out as much as my class AB PPI amp did. It could be that the car itself is tigher and dampens/muffles the output more. The enclosure I built faces rearward and the baffle board (or face) extends beyond the enclosure so it looks like it was made for the car (ie when in place, the baffle board's top, bottom, & sides butt up to the surrounding areas of the trunk & you are unable to see anything behind it). The trunk's airspace is right at the same amount as what I had in my Grand Prix, so I don't think that would affect the output. The subs are coming up on a week old with around 4 hours of actual playing time. Maybe they need to be broken in more, but I doubt I'd see a 10dB+ gain after they're broken in.

 

As I said, I'm about ready to pull my hair out. I've been putting stereos my vehicles and in friend's and family's for about 18 years, so it's not like I haven't done this before, but at this point I'm out of tricks. I've never had this much trouble getting good bass output in a car before. So does anyone have any suggestions?

Edited March 8, 2013 by sodak76

[edouble101 314]

You could be 10db higher/lower with the exact same setup in two different vehicles. The difference is cabin gain.  Different car, amp, subs and enclosure all add up.

[Quentin Jarrell 671]

If you used a pac adapter and tapped into the canbus wires then you turned a 2 volt signal into a .2 volt signal.  That's why it's not loud.  And asuming you don't have it out of phase.  The PAC guy either didn't understand you or he is full of shit.  If you have the polarity of the left and right channel out of phase they will null the signal.

Edited March 8, 2013 by Quentin Jarrell

[aimone 4]

Can you post pictures? im interested to see how your box is done. also what ohm are you running the subs at? have you tried turning your gain up on the amp just to see if it changes anything? you might also look into a ported box that will make a huge difference in output

 

i dont know jack about the pac stuff or going thru factory stereos im just putting so thoughts out there

Edited March 8, 2013 by aimone

[sodak76 0]

If you used a pac adapter and tapped into the canbus wires then you turned a 2 volt signal into a .2 volt signal.  That's why it's not loud.  And asuming you don't have it out of phase.  The PAC guy either didn't understand you or he is full of shit.  If you have the polarity of the left and right channel out of phase they will null the signal.

But if I've only got a .2V signal, why would I get the output voltage for the rated power output with the gain turned only 1/4 of the way up? By that I mean that when I used a DMM to set my gain, I hit 24.49V on the output side with the gain at just under 1/4 of the way from the bottom. If I had a lower signal, I should have to crank the gain to get that output.

 

The signal was nulled when I first played it. After reversing the + and - at the terminal cup the output came up. The only issue I have is that it's lower than I've had on any of my previous installs.

[sodak76 0]

Can you post pictures? im interested to see how your box is done. also what ohm are you running the subs at? have you tried turning your gain up on the amp just to see if it changes anything? you might also look into a ported box that will make a huge difference in output

 

i dont know jack about the pac stuff or going thru factory stereos im just putting so thoughts out there

I'll try to post some later.

 

I'm running the subs at 1ohm since that's where I'm getting the most power at. I might've gone with a different amp, but the plan was to use the eD subs for awhile and that meant running them at 4ohms using my PPI which dimmed my headlights in the previous car, or getting a monoblock 1ohm stable amp.

 

I tried turning the gain up a little bit, but the tone of the test tone I was using changed, and I figured it was clipping.

 

I would like to go to a ported box. The only issues with that is I come up shy on the space requirements for a ported box with two 12s. I could do it with one 12, but I don't think I'd see any gain over two sealed 12s. Plus this box came out perfect, & I'd hate to have to pitch it.

 

Thanks for any help you can give me.

[Jason Witt 65]

 This may be a shot in the dark, but do your back seats fold down? Did they fold down in your other vehicles? Again shot in the dark but worth asking to me.

[sodak76 0]

You could be 10db higher/lower with the exact same setup in two different vehicles. The difference is cabin gain.  Different car, amp, subs and enclosure all add up.

That's what I'm afraid of. The eD subs were the same between the two cars, but other than that everything else is different. I'm considering putting my PPI & eD subs in and see if it makes a difference. The reason I wasn't necessarily thinking cabin gain was that I didn't think it could result in that big of a drop. I mean 3dB is equivalent to a doubling of power, and 6dB is equivalent to being percieved as twice as loud and also doubling the amount of speakers.

 

If that's what it ends up being I'll probably end up pulling it all and selling it. To overcome 10dB would probably end up with me having to go to a much larger amp, higher power subs, big three and alternator upgrade, etc. Between my budget and the uncertainty of where I'd come out after all of that, it just wouldn't be worth it.

[sodak76 0]

 This may be a shot in the dark, but do your back seats fold down? Did they fold down in your other vehicles? Again shot in the dark but worth asking to me.

Yes, they folded down on both my Grand Prix & on the Charger.

[Quentin Jarrell 671]

unhook one of the rca's (left OR right) and see if it's louder

[sodak76 0]

Here's the pics of my sub enclosure. I think it came out pretty nice. The wiring could have been nicer, but I have it setup so I can quickly disconnect the wiring and pull the box if I need the space.

 

http://s1306.beta.photobucket.com/user/sodak76/media/20130307_222856a_zps0eb135bf.jpg.html?sort=3&o=0#/user/sodak76/media/20130307_222801a_zps1c360da5.jpg.html?sort=3&o=1&_suid=136271869351803327645846467486

 

http://s1306.beta.photobucket.com/user/sodak76/media/20130307_222856a_zps0eb135bf.jpg.html?sort=3&o=0#/user/sodak76/media/20130307_222801a_zps1c360da5.jpg.html?sort=3&o=1&_suid=136271869351803327645846467486

Edited March 8, 2013 by sodak76

[sodak76 0]

unhook one of the rca's (left OR right) and see if it's louder

I tried that and it makes no difference in the output. I would imagine since the amp is a monoblock that the inputs are summed and there won't be a noticeable change like there would be on a stereo amp.

 

I was hopeful going into it, but I'm still where I was before. I have a bad feeling that edouble101 is right and I'm fighting against cabin gain. It's odd considering that on the Charger forums plenty of people have subs in there car and seem to be getting good to great output. And as far as I can tell, not all of the amps are 1000w+ or anything. It's just damn frustrating.

[sodak76 0]

Talking to the nearest install shops they were skeptical that cabin gain would cause that big a drop. But they did suggest going to a ported enclosure, and possibly swapping in my old PPI A600.

Just curious, is there any issues with having a single chambered ported enclosure? In other words I would build an enclosure using the space requirements but doubling them, and port it. Or should I go the traditional route and have a dual chamber with a port in each.

If that's okay, as far as space I'm going to have to build it slightly smaller than spec, like around 2.5 cu ft plus port volume. Do you think that'll be an issue or are these subs a little forgiving on space requirements. I know when I started doing stereos you had to be dead on spec or the performance would be greatly diminished. Anything larger than that and I'll have to pull my box to change my tire. Anyways thanks for any help you guys can give.

Edited March 9, 2013 by sodak76

[sodak76 0]

Well, I found out a few things. First, I think one of the issues is my amp. While it is a new amp (Earthquake MiniD1000) it is also the first Class D amp I have ever owned/heard. On a hunch I hooked up the PPI A600 from my last install and rewired the subs for 4ohm mono and tried it out again. While it sounded much better, between the DCONs and the eDs (fixed my Ov series temporarily as well) the eDs sounded cleaner with around the same output. Aaron suggested going with a single DCON in a ported enclosure since the most I can go is around 2.25-2.5 cu ft total (damn narrow trunk opening). Just curious if anyone has gone down this road before, going from 2 DCONs sealed to a single DCON ported. Hoping that porting it will clean up the sound a bit. I know usually the opposite is true, but if the DCONs are more suited to ported rather than sealed it could be the reason why the eDs are sounding cleaner, since they were supposed to be better in a sealed box. Also looking to see if anyone thinks the output of a single ported DCON would be comparable to or better than 2 DCONs sealed.

 

On a side note, with the RMS rating of the DCON 12 at 300w, I'm assuming that's 300w total and 150w per coil. If that's the case that should work out great seeings the PPI puts out 150w @ 4ohm stereo. Correct me if I'm wrong though.

[Truconcept 58]

the oldschool ppi a600?  the one with the artwork?

i would guess thats better than the earthquake amp

[sodak76 0]

Yeah, although the Earthquake had subsonic filter, low pass x-over, remote bass control, and barely got warm when running. The PPI runs pretty hot and basically only has a gain adjustment. I've got a dedicated x-over with a line driver and rmt bass cntrl on the way, should be here tomorrow. Then I can start tuning a little better. Hopefully I hear something from someone on here about the subs so I can figure out my next move.

[sodak76 0]

Update: Well I believe I have things figured out. The cause of the low output was that this trunk is more airtight than others I've had. So I removed the factory sub and the lower rear deck cover (under the rear deck & speakers) and got a huge boost in output. Since the trunk was sealed so well it was choking off the output of the subs.

I have been using my eD subs since I posted last and decided to try the DCONs again and see how they sounded. Apparently the problem had a larger impact on the DCONs, probably due to their stiffer suspension (compared to the eDs). They really came to life, where before they had similar output, the DCONs now have a 3-4dB advantage over the eDs.

Besides that I added a crossflow fan for my PPI and it now runs about normal, and I put an active crossover with a line driver ahead of it. That really cleaned up the sound, so now I believe the only thing left is playing around with crossover points and the amount of polyfill in the enclosure. The only issue I have with the sound now is it appears to favor 35Hz and below, and stuff like kick drums are suffering. I believe if I use less (or no) polyfill that should raise my 3dB down point. But either way it's day & night from where it was before.

So if nothing else my experience should help people with Dodge Chargers & Chrysler 300s. If they have the factory sub in the car, removing it should give them more output from their aftermarket sub. If they don't have the factory sub, Dodge/Chrysler puts a cover over the sub hole so it would be best to remove that also.

Edited April 14, 2013 by sodak76

[SacredTanakh 67]

I honestly don't see 1 dcon ported being better then 2 dcons sealed. That wasn't the case when I tried it at least.

Not sure if your still thinking about that, but thought I'd give my opinion.

[Impious 1,476]

Peak output probably not, but the ported would end up having a stronger bottom end.

[sodak76 0]

If I did go with a single sub ported, it'd probably be with something like an Earthquake DBXi-12 that has an Xmax around 90mm (peak to peak). With the DCON having a p-p Xmax of around 36mm, the Earthquake is 2 1/2 times longer. My reasoning is maybe the Xmax advantage would make up for loss of cone area. But I think that once I get my current system tuned a bit more, and eliminate the rear deck rattle, I think it'll be what I was looking for. I can't really afford (monetarily) to play hunches at this point either.

[Impious 1,476]

Those specs on the Earthquake are complete and total bullshit.  Absolutely zero possibility the Xmax is 90mm peak to peak.  It's a lie, plain and simple.  It might have an Xmech of 3.5" peak to peak.  But that is most definitively not it's Xmax.   

[sodak76 0]

Okay, just going by what Joseph the owner told me. His techs were out and I talked to him about subs and how to get past the issues I was having. He was actually the one who suggested removing the sub & cover. The man's pretty knowledgeable, he worked in aerospace before starting Earthquake.

Even if it is Xmech, that still bodes well for it's excursion capabilities. Say worst case the Xmax is 2-5mm more than the DCON, that and going from a sealed to ported should give me close to the same output.

I also talked with the techs at Image Dynamics. Apparently my eD 13Ov.2s were made by ID and are comparable to their ID-12s. The tech modeled 2 ID-12s in a sealed box vs 1 IDQ-12 in a ported box. The Xmax difference between the ID & IDQ is only 1or 2mm, but output wise they were almost dead even, with each having a dB or 2 over the other at certain frequencies. And again that's with only 1-2mm difference between them. Looking at the excursion of the Earthquakes on videos vs that of the DCONs there is a visible difference, the one thing that does make me hesitate going with them is how much control does the sub have? Is that excursion due to a looser suspension than the DCONs? Will they just be SPL drivers and horrible at sound quality? Don't know. I have and Earthquake dealer but he's about 130 miles away, but he is on the way to family so I may check them out the next time I head that way.

Like I said, at this point I'm gonna do what I can to make these work. I need to soundproof the rear deck, play with the crossover a bit, & I may try sealing off the factory sub hole around a 4" flared port. I believe that will give me a little boost over the 8" hole that is there now.

Edited April 15, 2013 by sodak76

[Dictator 39]

unhook one of the rca's (left OR right) and see if it's louder

I tried that and it makes no difference in the output. I would imagine since the amp is a monoblock that the inputs are summed and there won't be a noticeable change like there would be on a stereo amp.

 

I was hopeful going into it, but I'm still where I was before. I have a bad feeling that edouble101 is right and I'm fighting against cabin gain. It's odd considering that on the Charger forums plenty of people have subs in there car and seem to be getting good to great output. And as far as I can tell, not all of the amps are 1000w+ or anything. It's just damn frustrating.

i know the problem is fixed but..you should of had less output if you unplugged one rca 

Edited April 15, 2013 by Dictator

[sodak76 0]

If the output was lower it was minimal. I reasoned that because it was a mono amp that it may not make as much of a difference as with a stereo amp. This is only the second mono amp I've owned (a Kenwood KAC-714 was the other) so I don't have a lot of experience to draw from on them versus how things work on a stereo Class AB amp. This was also my first Class D amp and after using it I'll stick with AB amps from now on, although I've heard that Memphis's Class Ds sound pretty close to an AB amp. For me it didn't sound natural, like trying to make a guitar sound on a keyboard, if that makes any sense. As far as I was taught in school (electronics tech) Class D was usually reserved for oscillators, due to their using a square wave rather than a sine wave. For me they'll never have as true a sound as a Class A or AB amp, just like when people say you lose a lot of the warmth of sound going from a record to a CD, or a CD to an Mp3, due to the frequency compression. While it's not that bad, I do notice a difference when playing a CD and an Mp3 of the same track, the Mp3's sounds quieter and a bit muffled compared to a CD, & I always rip them at 320kbps or lossless, which should be at least equal to a CD. Anyways, since I'm not using the Earthquake amp either it's a moot point.