2 X 12" 4 ohms DVCs wired right?

Ok, here's how I setup my 2 - 12" Fosgate DVC woofers to get 4 ohms to match my 2 channel amp mono bridged at 800 Watts. Please tell me if I did this right or not.

1. Each woofer has a wire running from + to - on one voice coil.

2. A seperate wire runs from the other voice coil to the + and - terminal going to the box input.

*Both DVC woofers wired in a series. 8 ohm load without further wiring*

3. 2 - 6 to 8" wire runs from each + and - terminal on the outside of the box.

*Both DVC woofers wired together in pararrel. 4 ohm load*

Did I do this right or did I do it backwards? Do I have a 4 ohm load or do I need to wire in pararrel on the voice coils then wire in a series on the outside of the box?

The reason why I ask is my amp seems to go into protection when I turn up the volume to 80% or so. This is with the bass really pounding in my trunk. I was testing it on a rap channel on Sirius satellite radio.  I see the green light turn into red on the amp. I'm getting very good bass from this setup but I would think I could get the volume higher?

Believe or not that Coustic 480QE is running my 4 MB Quarts excellent. The SQ is great inside of my car. This is my 2nd run with MB Quarts and I love them. These 4" speakers sound like they're at least 6 1/2's! The components up front sound crystal clear. Very nice. I was watching Gladiator earlier in Dolby Digital surround on my Panasonin 7300 and it sounded like movie theatre. These Panasonic in dash DVD players have pretty darn good SQ. I think it sounds a little better than my past Kenwood 911 DVD? Newer technology too. I got the Kenwood DVD when it first came out 3 years ago.

# 2 represents a seperate wire on each + and - (2 wires total) running to the + and - terminal inputs. Then the + terminal on one woofer and the - terminal on the other woofer run to the amp in bridged mono at 4 ohms. I wanted to clarify that since I'm a newbie.

Sirius satellite radio is pretty cool. I signed up for it tonight. It's $15 joining fee + $12.95/month. It's more the 2X the cost of XM Radio but it suppose to be 100% commercial free. I think I heard a XBOX commercial though? Maybe it was the radio? I'll try it for a few months and see if I want to keep it. I paid $99 for the unit and $50 for the Terk antenna at Fry's. My Panasonic 7300 is Sirius ready so I figured if I spedn this much $ already I might as well keep going. I guess I would need the upcoming navigation system and the rear view camera to max it out. Oh yeah, a CD changer too...Ahhhh, I have TV in my car again. I missed that for sure.

Well, I took my '90 Lexus LS400 down to a parking lot to tune my stereo tonight. Let me tell you that it feels like my head is still under some kind of compression or pressure. Jeez, that stereo is nuts. I didn't experience any clipping (amp shut off, protection) this time. Do amps have a burn in period like computer parts? Or maybe this Ultimate amp does because it's digital? I dunno but that was cool....

I was playing the Dance stations in the 60's on Sirius satellite radio. Now that's the kind of music I listen to so I really got a good idea of what this system can do.  When you sit in the back seat it's like some kind of torturous back massage with no theraputic value. Hehe.... I'll tell ya, these Ultimate amps put out some serious power for their size. The footprint of the amp is slightly smaller than the Coustic 480QE amp and it's even a little lighter but not much. These amps are heavy. I mounted the amps with the cap onto the box. That box seems to weight over 200lbs now. Talk about junk in the trunk....

I still want to know if I wired this right? I think it is?

Dude, the wiring that you have done sounds correct. However the problem with the amplifier going into clipping can have many sources of problems. Try some of this and it should run happy for years. Rockford amps are great, but as along time dealer we have done some serious work with them in order to solve problems. An amplifier will go into protection (red light) because something is telling it to, you need to find out what it is, maybe some of these steps will help you to find out.

(1) Resistance on a ground lead. What is this? This is the simplest way to explain it. Go into subway and eat a foot long sub and then have someone sow your crack shut. Current flows from negative to positive, your ground lead should in all cases be the same size as the power lead, by the sounds of your amp it should be a 4 gauge wire with a high strand count. Connect the ground lead direct to the battery. The assumed proper way of grounding is to keep the wire as short as possible, the problem here is that the resistance of the vehicle ground can be quite high. The correct way to ground your amp is to meter the ground resistance. If you take your meter and put one lead on the neg battery terminal and the other lead where you have your ground currently (assuming that it is grounded close to the amp) it will give you a measurement of resistance in ohms.(make sure the meter is set to measure resistance) Anything above .5 ohm means that you should be grounding to the battery. Make sure that you also upgrade the battery to vehicle ground as well.

(2) Make sure you have a cap for the amplifier.

(3) Turn your gain on your amp down, it is not a volume control, it is a matching device. Gains are designed to be turned down not up.

(4) Most cd and dvd players have what's called pre-outs, however even though some of them list 2/4/5 volt preouts, many of them do not actually give you this amount of voltage. Further to that the preouts actually clip -which causes distortion to be produced at the cd/dvd player that your amplifier says ok I'll amplify distorton for you, which causes the sub to produce the same distorion as well. You'll need som trial and error to find out where approximately your cd/dvd player starts to clip, turn your gain down on the amp when you find that level.

(5) Make sure the amp has adequate ventilation

(6) If the subs are new they may need to break in

(7) Loudness is also going to have alot to do with your box, post a reply to me about your box and vehicle and I'll go though it with you. I don't know if you have a local dealer there that is helping you, if you do great, if not I may not be local (Vancouver Island -BC) but when it's quiet here I don't mind helping others.

(8)For an experiment if you have a friend or dealer that carries Eclipse, try a Eclipse CD5423 cd player. It has a true 5volt non - clipping pre-out. You have a great system right now, just give it a try if you can, you just might be amazed. Eclipse is not a company that builds something to hit a price point, they build something to sound way better than anyone else. They have their strong points in the line and they have their weak points, trust me that the cd/dvd players are one of their strong ones. I'm not trying to sell you something, just give you some advice tht you may not have yet.

Thanks for the great info forebidden!

I actually have the Ultimate DT2-800 Digitalis amp (fully digital)> https://www.ultimate-sound.com/pdf/technical/platinum/dt2-800.pdf It's a pretty darn good amp by what I've seen so far. I'm impressed. I got this amp for $200 (MSRP $699) on a special purchase buy at SD. I see that they don't have them anymore. I'm running it at 800W X 1 bridged, 4ohms.

I played the system at full load for a quite some time today and it did not clip once. I was listening to mainly satellite radio. Hmmmm, was it the woofers breaking in? The system sounds pretty good. I would have to say this does sound better than my old Kenwood 911 DVD. Suprising to me because I did not know Panasonic had good SQ. Not as good as Eclipse (but who is) though. This is now my nicest system to date.

I have the RT medium 2 X 12" MDF box. It's pretty big and really heavy. Maybe 150lbs with both amps? I have it in the trunk of my '90 Lexus LS400. Should I put some kind of dampening material in the box for even better bass response?

Yeah, gain is actually a (bad) noise enhancer so you want to have it at the lowest setting possible. I learned that a few years back.

My system seems to be running pretty good now. I probably spent 5 hours in my car (moving and sitting in driveway) listening to my system and watching the Gladiator DVD.

I'm running this Coustic 480QE amp to run my 4 MB Quart speakers, front and back.> https://coustic.com/classic/PDFs/Coustic320.480.QEManual.pdf The SQ is actually a lot better than I thought it would be for this amp.

Both amps get warm at best after a long period at full load. So I don't have a overheating problem.

I have a 1 fared capicitor  w/digital read out going to both amps. I live in the Seattle, WA area. Thanks for your help, I appreciate that. :)

I had everything installed at car toys> https://www.cartoys.com/

Chad, the installer, did a very professional job. One problem that I have is a slight whining thru the speakers when muted. I suppose it needs to be grounded better or to the battery"? He said to bring it back if there is anything I want adjusted. Will they just put a noise filter on it and try to call it good? I hope not.

These MB Quart Reference speakers are VERY NICE. I am very pleased. This is my 2nd run with MB Quart's. I think I will stick with this brand for life? I have components up front and 2-ways in the back.

Toddnaz, sounds like you've got a great local shop and installer to help you along. Make sure about that amp ground though, make sure it's right to the battery, any shop that I've ever worked at has never ever done this as I pointed out above. MB Quart - awesome - totally awesome.

For the box question - here you go. I am going to assume that it is a sealed box, made out of 3/4" and hopefully they installed it with the subs pointing towards the back of the car. How would I improve on it? I would remove the subs, resilicone all inside edges, let it dry, then I would paint the inside of the sub box with whatever spray bomb you have lying around (mdf is extremely porous and bleeds air badly - the paint seals the mdf) and finally I would use a product called bassline. Bassline (or eggcrates as my customers call them) are a product that is manufactered  who knows where but is available here in BC. It is really cheap, install with spray adhesive and screws and really tightens up bass response. It is made out of recycled pulp paper and pressed into a shape that resembles a egg crate that would hold eggs the size of a robins egg.It is available in panels about 5x12". Works just god damn awesome. If you want some let me know I'll see if the distributor can promo you some.

Yes, I will do as you say forbidden. Yes, my box is sealed and pointing back. I would love to buy some bassline from you. I'm only about 100 miles from you in Seattle. Me and my girlfriend were up in Vancouver 2 weeks ago the night before your Thanksgiving. We stayed overnight.

Yep, I told the installer to wire the ground to the battery terminal and he said it'll be fine. Well, it's not fine. Actually I find the whining noise very unacceptable after driving the car this evening. I paid this shop $600 to install this so there better be no whining. He told me I could bring it back anytime. Well, I'm bringing it back tomorrow. They install 7 days a week.

What would be an alternate ground at the back of the car (by trunk) that would be a good choice to ground? I can do this stuff myself but this stuff is too expensive for me "the amature" to screw up. I can hear the whining at lower volumes and I can't live with it. Not with the money I spent building this system.

Thanks for your comprehensive help forbidden. :)

What kind of cd player r u using. It sounds like a difference in ground potentials. What this means can be interpreted many different ways. One basic way is that if there is a bad ground in a power supply the circuit will go looking for another one, possibly through the rca cables. What speakers does the whining come through? R u using an amplifier on your other speakers? If you disconnect the rca cable from the sub amplifier does the whining go away? Is the whine worse with the lights on. If the amplifiers r mounted to metal, unmount them and put them on a piece of wood lossely for now, does the whine go away. (ground loop). You don't sound quite so amature to me, just dealing with issues that r common to the car audio environment. Now I'm sure the shop has done a great install, so try not to come down hard on them, noise problems r definitely not their fault, usually they have no idea that these problems will pop up. Try these things yourself, cus u r right, time is $ that you might not want to keep spending. One little quick fix is called a ground loop isolator, one like the scosche es034, available for about $30.00 cdn. This might not solve the problem but it probably will help make things much more tolerable. If you have a Pioneer cd player (my guess) try a different cd player, hell try a different one anyways. The problem might go away. My chick's out of town and I'm bored, nothin on the tube so I thought I'd see how u r doin.

My screw up, forgot you have a dvd system, most Panasonic heads  have little if not any noise problems. My next guess is your Coustic amp, I imagine this is where the noise is being generated, unhook the rca's from it, does the sound go away? Try everything I mentioned with this amp as well.

Ok, here's my system above. I took this picture this evening. I should of did it earlier when it was light? Anyway, this is my setup less the MB Quart speakers in the doors of course.

You think the enginge whining sound is because of the Coustic amp? Isn't the whining usually from a bad ground? Thanks for your help forbidden.

I disconnected the front speakers from the Coustic amp and hooked them up to the Ultimate amp for testing. The whining is coming from the Coustic amp in 4 channel mode. There was no whining with the Ultimate amp. I also noticed there was no whining in the back speakers only when I had the front speakers connected to the Ultimate amp. It seems the whining comes out when all 4 channels are being used on the Coustic amp. I guess that's what I get for trying to use a cheaper amp. It actually sounds really good. It just bothers me when it's at very low levels. Maybe I'm picky but I want to do this right. Thanks for your help.

Was a good clean 4 ch amp with 75W - 80W RMS per channel?

forbidden wrote:

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My screw up, forgot you have a dvd system, most Panasonic heads  have little if not any noise problems. My next guess is your Coustic amp, I imagine this is where the noise is being generated, unhook the rca's from it, does the sound go away? Try everything I mentioned with this amp as well.

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Here is a good amp for the money. 

https://www.sounddomain.com/sku/USAUSX4085

Did you check your RCA's? It is not uncommon to get a bad set that that will drive you nutz thinking that it's your equipment.

fuseblower wrote:

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Did you check your RCA's? It is not uncommon to get a bad set that that will drive you nutz thinking that it's your equipment.

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They used Streetwire RCAs so I believe they are fine? They have kind of a silver nylon weave insulated around them.  The RCAs also have grounds on r & l (red & black) that are not being used. After testing the fronts on my 2 channel Ultimate amp while experiencing no whining with the same RCAs, I would assume they are fine? Right?

Toddnaz, the chance of the rca cables being at fault is slim to none, same with the chance (but check anyhow) that they can the rca's by the power. More than likely it is your coustic amplifier that is built in singakoreatiawanapore. Not that this is bad but the power suplly's immunity to prevent noise is just not there. The scosche ES034 ground loop isolator may definitely help you out. If you are going to go the mile and get a new amplifier make sure it is built in the US, very, very few noise related problems here. Now most american built amplifiers have much larger power supplies (higher current) and to drive the MB Quart 's good and clean you can actually look at small as 50w x4 rms @ 12v from 20-20000hz. If you must look for a spec this is where you want to be, anybody's KRAFT built cheez machine can hit 100w x4 for power at 1000hz @16 volts. Now some manufacturers rate their power at 14.4, that's fine, knock of 20% of it's output approximately to hit 12 volt power output. What would I recommend... Eclipse PA5422, any Orion, Xtant, Soundtream (not Soundstorm), PPI and whole pile of others. Soundstream is a really old American amp company, not excessively big, has had financial problems in the past (now solved big time - these guys will be huge in 2 years) but build really really nice sound quality amplifiers, they would be my first choice if you can find a dealer, otherwise look at the Eclipse then Xtant.

Thanks for the tips forebidden. I have a Alpine MRP-F240 (40 X 4) in my boat that I could use in my car. I won't be using my boat until nex May at the earlies up here in Seattle. I think I want to buy at least a 75W X 4 amp so I can maximise my MB Quart speakers. These speakers sound AWESOME. The sound really good with this cheap-o Coustic amp. It's just when you are listening at lower levels is when you can hear that slight whine. The whine isn't really that noticable or horrible, I notice it and it bothers me. Most "non audio freaks" would probably live with it and not complain. I spent $3,000 on this system in the last few weeks so it better sound good.

I think those US Acoustics amps are a great value. I may get the Kicker KX800.4 at 100W X 4, 4ohms? I can get that amp at a great price right now. I know my MB Quart speakers are rated at 80W RMS max so would this amp blow them sooner or later? I figure I could turn down the gain? This would be my last piece to the puzzel I think? My Ultimate amp seems to be pushing my 12" woofers pretty darn good and clean.

I wonder if I ran my Alpine amp at 2ohms X 4?> https://www.alpine-usa.com/html/D2_n_1_n_n.html

I would I wire my speakers front and back to show a 2 ohm load at the amp? Would I still have r & l, f & b fading? Would this Alpine F240 amp be a better choice over the Coustic 480QE?

Not bad, is that the only American built amp they carry?