Need some help W/ choosing sub
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New member Username: KmurdaPost Number: 1 Registered: Sep-11 | Okay so I am 18 and really getting into the car audio scene, I've had my fair share of sub installs but have never fully understood it all. To start off I have a Kenwood KAC-7203 amplifier and currently have 1 DVC 4 ohm Rockford fosgate punch (p2) It really doesn't have the sound I am looking for. I am really interested in buying an 12" Infinity 1260w DVC. Will the amplifier that I currently have adequately power this sub? Should I get the 2ohm or 4ohm version of the subwoofer? Please help, I am really trying to get a good setup for my truck!! |
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Gold Member Username: KaerfplSpencerport, NY USA Post Number: 1373 Registered: Jun-06 | Your Kenwood KAC-7203 is a 2-channel Amplifier with the following specs below: 4 Ohms : 170 Watts RMS x 2 2 Ohms : 250 Watts RMS x 2 1 Ohm : Not Stable 4 Ohms Bridged : 500 Watts RMS x 1 With these specs, I would suggest looking into a Subwoofer with a range of 300-500 Watts RMS and have..... Suggestion #1 : One Subwoofer that is a 4 Ohm SVC wired in Parallel. Suggestion #2: One Subwoofer that is a 2 Ohm DVC wired in Series. Suggestion #3: Two Subwoofers that are 4 Ohm DVC wired in Series/Parallel. All three suggestions will provide you with a 4 Ohm load which when Bridged on your Kenwood KAC-7203, will give you the most Watts RMS output. With that said, your current Rockford Fosgate P2 is a 4 Ohm DVC Subwoofer with 250 Watts RMS (assuming it's the older version). The only configurations you can wire that into is either 2 Ohms wired in Parallel or, 8 Ohms wired in Series. Because of this, odds are you are not even seeing the true potential of what that P2 can really do. Now the Infinity Reference 1260W is a 4 Ohm SVC Subwoofer with 300 Watts RMS. Overall, this Subwoofer would be a better match Bridged with the current Amplifier you have. Below is the link for the Subwoofer for you to look at: http://www.sonicelectronix.com/item_18916_Infinity-Reference-1260W.html Also something else to consider as well, is that it is not always the Subwoofers fault for poor performace or not being as "loud" as you would like it to be. The Enclosure itself plays a HUGE roll in how your Subwoofer will perform. Typically, most pre-fab Enclosures are not built and/or tuned to specific Subwoofer Specs which will result in poor performace and output. Overall, I would personally go with the Rockford Fosgate P2 over the Infinity Reference 1260W. If I were you, I would..... Suggestion #1: Sell the Kenwood KAC-7203 and look into an Amplifier to support your Rockford Fosgate P2. The Rockford Fosgate PRIME R250-1 would be perfect Amplifier for you. Link is below: http://www.sonicelectronix.com/item_21680_Rockford-Fosgate-PRIME-R250-1.html Suggestion #2: Purchase another Rockford Fosgate P2 with the 4 Ohm DVC and wire it in Series/Parallel so you may use the Bridged feature on your Kenwood KAC-7203. |
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Gold Member Username: Livin_loudMW2 Addict Post Number: 3530 Registered: Jan-06 | lets see here where do we start.. first off what are you trying to accomplish with your setup? do you want to get loud or have it sound good? don't say in the middle, either. there is none. second, that amplifier, while it can still do the job, should be replaced with a class d amplifier which is more geared toward subwoofers and is also more efficient (meaning less stress on your electrical system, ie battery and alternator) third, the enclosure your sub is in and its positioning can make a massive difference, so that needs to be taken into account. let me/us know what you would like to do, what your budget is, and if you are willing to take suggestions for different equipment. you won't be lead in the wrong direction. |
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New member Username: KmurdaPost Number: 2 Registered: Sep-11 | I appreciate all the help I can get! you both seem to know what you're talking about. Let me add that I have a 2004 dodge ram 4 door. as far as money goes I don't have a lot of it now but i would like to stay in the 250-300 range for a sub and amp. The kenwood amp that i currently have was given to me along with the subwoofer. I knew that the RF wasn't being played to the full potential and I have reasons to believe the subwoofer isn't in the best condition, may be the lack of power, but it has a lot of distortion when turned up. I want a good sounding system. The enclosure is one that I bought from wally world just to throw the sub in.. It's sitting right behind my center console (in between the rear seats and center consule) I believe the total box volume is .75 cubic feet. |
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Gold Member Username: KaerfplSpencerport, NY USA Post Number: 1374 Registered: Jun-06 | From what you just stated I can already see a few problems. To start off, odds are that the Kenwood KAC-7203 is most likely did not have it's settings correctly tuned, resulting in the distortion that you are reffering about. Also, the Subwoofer Enclosure you purchased im going to assume is a Sealed Enclosure, since i've never seen Wal-Mart sell Ported Enclosures before. Because of the Subwoofer Displacement of 0.057 Cu Ft, your Enclosure now becomes a 0.693 Cu Ft Sealed Enclosure. The recommened Enclosure size for the P2 in a Sealed Enclosure is 1.0 Cu Ft and as you can see, you are well below the recommendation by 0.307 Cu Ft. As a result of this, the incorrect size Enclosure is also going to contribute to distortion and poor performance. Overall, if you planned on keeping the P2, you should look for a Sealed Enclosure with an internal volume of anywhere from 1.0 - 1.1 Cu Ft or a Ported Enclosure of an internal volume of anywhere from 1.8 - 1.9 Cu Ft tuned to 35-36 Hz. Because certain recommendations are not always easy to find, most people end up building their own Subwoofer Enclosure. Building an Enclosure is usually cheaper than buyer one assuming you already have the tools to build one. The last Subwoofer Enclosure I built only costed $35 for a sheet of 3/4" Wood and $5 for Wood Screws and Caulk. |
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New member Username: KmurdaPost Number: 3 Registered: Sep-11 | I have all the settings turned about 1/4 of the way on the amp, if that tells you anything? Would it be possible for me to get a shallow mount subwoofer to fit in the box? and still be able to run it off the kenwood amp I have? |
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New member Username: KmurdaPost Number: 4 Registered: Sep-11 | maybe something along the lines of this? http://www.crutchfield.com/p_113KFCWS12/Kenwood-KFC-WS12.html?tp=111&nvpair=AG_G eneral_Features%7cFFShallow_Mount&tab=features_and_specs |
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Bronze Member Username: John253aAust. Post Number: 80 Registered: May-11 | Do you have the ability to build a ported box? If not there are a few options 1. buy a sub in a prefab box (one designed for that sub) 2. find a box that fits car, find all spec on box and chose the best sub for that box 3. build a sealed box. If you can what is space available? some options are, keep amp and find sub's to suit get a new amp/sub build/buy box and get another p2 if you are experienced in box building there are a few sub/box packages available to suit 500wrms@4ohms around $300 http://www.sonicelectronix.com/item_21900_Kicker-VCVR154-10VCVR154.html http://www.sonicelectronix.com/item_11400_Kicker-VS10L74-08VS10L74.html http://www.sonicelectronix.com/item_34873_Rockford-Fosgate-P2-2X12-11P2-2X12.html And change wiring for 4ohm If your willing to give building a box ago the options are endless |
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Gold Member Username: KaerfplSpencerport, NY USA Post Number: 1375 Registered: Jun-06 | The Kenwood KFC-WS12 is a SVC 4 Ohm Subwoofer and requires 350 Watts RMS. This Subwoofer itself is a better match for your Kenwood KAC-7203 than the Rockford Fosgate P2. With the Amplifier/Subwoofer compatability out of the way, we now have to take the Enclosure into consideration. The Kenwood recommends a Sealed Enclosure of 0.80 Cu Ft and has a displacement of 0.061 Cu Ft. With your 0.75 Cu Ft Sealed Enclosure, we are looking at a total internal volume of 0.689 Cu Ft after the Subwoofer has been installed. Not perfect, but the difference once again is a better match than the Rockford Fosgate P2, making this a much more logical choice to pick with your current Amplifier and Enclosure. However, all because the Specs match up better, we need to face the facts. Shallow-Mount Subwoofer are not going to be "loud" and achieve high decibel levels although, it should be more looked at as a SQ (Sound Quality) setup. If a SQ setup is what your looking for, then this may be the best option for you at this time. In my opinion, I would suggest looking into a new Subwoofer Enclosure, as Wal-Mart Enclosures are very cheap and sound horrible. Below is an example of a better Enclosure to look into for your 2004 Dodge Ram: http://www.ebay.com/itm/DODGE-RAM-10-VENTED-QUAD-CAB-02-UP-SUBWOOFER-SUB-BOX-/27 0808653873?_trksid=p5197.m263&_trkparms=algo%3DSIC%26itu%3DUCI%252BIA%252BUA%252 BFICS%252BUFI%252BDDSIC%26otn%3D12%26pmod%3D280731465952%252B330600928619%252B27 0808653687%26po%3DLVI%26ps%3D63%26clkid%3D2675232825084597389 This Enclosure is Custom Built for the 2004 Dodge Ram Quad Cab which has been built from 5/8" MDF and allows you to install two 10" Subwoofers. Each Chamber has an internal volume of 0.69 Cu Ft and a mounting depth of roughly 7". This Enclosure will work perfect with two Image Dynamics CTX108 Subwoofers. They are SVC 8 Ohm Subwoofers with 175 Watts RMS each. Wired in Parallel, will allow you to use your 4 Ohm Bridged mode to get the most Watts RMS out of your current Amplifier. Also, these Subwoofers have a Displacement of 0.050 Cu Ft which will result in an overall internal volume of 0.64 Cu Ft per chamber. The recommened amount of space that is required ranges anywhere from 0.60 - 0.90 Cu Ft, which works out great. Something else to consider to attempt to boost the performance of the Image Dynamics CTX108 Subwoofers, I would recommend looking into some Polyester Fiber Fill. You can find this cheap on sonicelectronix.com for $5.99 per bag. I'd look into grabbing two, one for each Chamber Below is a link to the Image Dynamics CTX108 Subwoofer: http://www.sonicelectronix.com/item_22190_Image-Dynamics-CTX108.html |
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Silver Member Username: Joe1234Post Number: 407 Registered: May-09 | Kmurda, are you saying that you have the input gain of your amp set to 1/4 ??? Also using a dual 4 ohm coils subwoofer on a four ohm stable amplifier (bridged) is a wrong choice, happily there is a workaround below. You have your whole system misconfigured. To setup your system correctly PLEASE READ CAREFULLY: A) configure the connections between the amp and the sub for maximum power: 1) flip the stereo/mono switch on the amp to MONO, 2) wire the left channel of the amp to one coil watching the correct polarity of the connections to the amp positive on the amp to positive on the coil, negative on the amp to negative on the coil, . 3) wire the right channel of the amp to OTHER coil also watching correct polarity of the connections to the amp like in 2. The coils must NOT be connected in any way to EACH OTHER. That would put 340W RMS into the subwoofer in a very safe manner. B) Setting up the gain on your system: 1) turn down the "input sensitivity knob" almost at minimum. 2) turn up the volume in the head unit to the max level that it gives a clean sound (the bass tone control should be "0"). 3) turn up the "input sensitivity knob" on the amp as far as you don't hear distortion. C) Setting up the other knobs: If you have LPF filter enabled on the amp (Fiiter switch to LPF) the "LPF Frequency" knob should be set below the 70Hz marking between 50 or 60Hz. Also if you want to do upgrades to your equipment state a budget. |
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Silver Member Username: Lord_huggingtonOntario Canada Post Number: 444 Registered: Oct-10 | If going ported (3-5 cubic feet NET), check out the SSA DCON 15" 300W RMS for $139, it should be a lot better than RF & Infinity. |
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New member Username: KmurdaPost Number: 5 Registered: Sep-11 | @ Joe Durkham So If I am understanding you correctly I wont be using the bridged feature on my amp? Instead I will be using all four (+,-)(+,-) outputs on the amp?? Im a little confused (sorry) Im not understanding what you mean by the left and right channels? |
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Silver Member Username: Joe1234Post Number: 430 Registered: May-09 |  Correct don't wire for bridged mode you wont be using bridged but the stereo/mono switch must be set to mono. Very important. This is a screenshot of your manual just imagine that each speaker that is shown is a coil on your subwoofer. polarity is very important so wire just as shown. On the sub red is for positive black is for negative. If you do not understand the slightest thing ask before making any connections. If you want post a pic so that I can see if its right. |
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New member Username: KmurdaPost Number: 8 Registered: Sep-11 | okay I understand! one more question.. how do i run both pair of the positive and negitive wires through my box to hook up to the sub if the box only has 1 positive and negtive port |
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Silver Member Username: Joe1234Post Number: 432 Registered: May-09 | Kory, yes that's obviously a problem, for now unscrew the terminal block and run in cables straight from the amp, stuff something on the hole to prevent airflow through it f you decided to keep the sub then a second terminal block should be put. Or just quit right now and get either a four ohm sub single coil or an amp stable at 2 ohm bridged. Or a monoblock amp also stable at 2 ohm. |
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New member Username: KmurdaPost Number: 9 Registered: Sep-11 | Got it figured out, all hooked up & working. im going to look into getting a new subwoofer like you suggested. thanks for all your help! |
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Bronze Member Username: KmurdaPost Number: 11 Registered: Sep-11 | @ Joe durkham I went out and bought a dual 10" subwoofer box that will fit under the rear seat of my truck.. I have a pair of 10" pioneer shallow mounts 4ohm SVC 200 watts rms subs that I'm going to install and run them w/ my kenwood amp.. But here's another thing.. I just purchased a new HU (Sony DSX-S100) for my 2004 Dodge ram 1500 4 door and a pair of alpine 6X9 (SPE-6090) for my front doors (the stock infinity 6x9's were completely blown) I installed them right in place of the stock ones with the stock wires that were already ran through the doors. I believe alpine is a good company and the speakers have good reviews but there really isn't that good of sound quality coming from the speakers.. sounds muffled in a way?? I feel like something isn't right and they could sound a lot better.. Do I need to run the speakers to an amp to get better sound? or maybe change the LPF & HPF settings on the HU? |
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Silver Member Username: Joe1234Post Number: 468 Registered: May-09 | First thing to check if you are using the stock covers is that the speaker suspension rings are not hitting them. Yes, the HPF can be set up at 80Hz for the front speakers in that HU, so that is something you can try. Also you can try to hook them up to the amp you have, to do that you should set the FILTER switch to OFF and set the bass boost to 0 dB, and start with a low gain to avoid overpowering them. If still too much bass is going to them set the FILTER to HPF and the HPF frequency knob set to 60-70Hz. From there you will know if you want to get an amp, a two channel decent brand 60-80W RMS per channel will do for them. Lastly that HU brand is not known for top sound quality, for that you should stick to Pioneer or Alpine. You can try both, if like the results with the amp then get another one |
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