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Car Audio, Video, & GPS

Car Audio, Video, & GPS
Talk about stereos, navigation, amps, subs, and all things car audio


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Hi, I am kinda new to posting in the forum. So excuse me if I do anything wrong or looked down apon, lol. So This is for mainly audiofiles who have experience installing systems and what not. OK, so here is the situation. My goal is to have a very nice sounding SQ sound system in my 350Z. Nothing crazy or ridiculous just something nice sounding with a little 3D staging. I have put in a cheap system in before but now I have moved on. I bought a pair of Focal ES165KX2 Components for the front, a pair of Focal EC165K2 Coaxials for the rear, and a Focal E25KX 10" Sub in a sealed box in the rear. I have them being powered with an Alpine MRV-V500 5 channel amp (I know this is not much but it's all i have at the moment.) The front components are meant to be biamped and since i don't have enough channels at the moment I just have 2 wires coming from each terminal (a + and - for the woofer, and a + and - for the tweeter.) But only for 2 of the channels. I have the coaxial's being powered by channels 3 and 4 and i have the sub being powered by the 5th channel. I am also running a Kenwood Headunit (DNX772BH) But I have reason to suspect that the channels are fried in it or something cause it just does not sound right if i don't have the position adjustment  (the setting where you put in how far the speakers are from you.) set to something beside 0.00 feet. Either way it's just fucked up. I really need help with deciding what I need to get now in order for it to sound good. Cause at the moment I don't think it sounds all too hot. The car is fully sound deadened and i could take it to a shop and have them tell me but I would really like to learn off of this and do it my self. I just need help deciding if I need to get new amps first, headunit, DSP, or what amps to get, and why . I'd really like to use the focal speakers however because they were pretty pricey and I  would be cool ditching the alpine if its not needed and or getting a new head unit. Please help me and it would be helpful to provide links to what you recommend to get in order to complete this build so it sounds bad ***. Thank you.

All Replies
  • I would ditch the rear coaxials, they throw off the sound stage. Its a 350z so there will be nobody in the back. The Focal components can be bi-amped, so you can run the tweets off channels 1 and 2 and the mid bass off channels 3 and 4, and the subwoofer on channel 5.

  • You have good components but they are not matched to your amplifier. Your amplifier is not powerful enough to drive the subwoofer properly. That subwoofer wants at least 600 watts RMS and you have 250 RMS watts. You either need to downgrade that subwoofer or upgrade to a dedicated mono subwoofer amplifier that can put out a true 600 watts into 2 Ohms. Consider the JL Audio W3V3 or even better the Sound Solutions Audio GCON for a better sub. If you want the best SQ that Focal subwoofer can offer than pay attention to the box recommendations from Focal. Even though a sealed box is hard to screw up, a poorly constructed or improperly sized box can make a good driver sound bad. The box should be 3/4" braced high quality MDF and even be 1-1/2" thick at the face panel. You will have to subtract the displacement of the driver to get to the true overall box volume correct.

    Some good Amplifier brands to look at are Rockford Fosgate, JL Audio, Audio Control (with or without DSP) and on a budget Pioneer, Kenwood, Sound Ordinance, NVX, Kicker, and MTX. The main difference between a more expensive amplifier and a cheaper one is in the features it has and the power supply. With the more expensive brands you'll likely get a more robust power supply enabling greater power output with lower Ohm loads or they may be more efficient drawing less power to make the same wattage. The more expensive brands will also tend to be more forgiving with noise rejection too. So long as you buy good know brands though the amplifier isn't going to make hardly any difference given that they are of the same wattage. If fact its highly unlikely you will be able to ever notice any difference at all (I've tried) in an apples to apples comparison (not driven into clipping) so pay more attention on getting more wattage for your money and buy the best one you can afford. Now if you are talking no name brand Chinese knockoffs that are not CEA Compliant and claim they make 1000 watts RMS for $100 well than that is different.

    Make sure the Focal woofers you installed in your doors are sealed properly to the door with a gasket or the sound will lack bass response and may sound off. Try and use foam to seal the edge of the woofer to the interior door panel so you are directing sound out and not having it bounce around between the interior door panel and metal door.

    Tweeter placement is critical and the worst place for them to be is in the dash corners facing the windshield reflecting off the glass in that crowded area. Because higher frequency's are more directional, its best to try and get the tweeters to face directly at you as much as possible. The A pillars and front sail panels are better locations. You can also buy much better tweeters than you will ever be offered in a typical component system from places like Madisound or Parts express for far less money that are designed for home audio but work just as well in a car. I've used 4 and 8 Ohm tweeters from Tang Bang, Morel, and Vifa/Peeless that make even the tweeters from JL Audio's Z series sound Meh. SB Acoustics, some Dayton Audio, and Seas make some really impressive speaker drivers/tweeters that put most dedicated automotive built tweeters to shame for much less money.

    Make sure you have beefy enough wiring and an electrical system to support the amplifiers power requirements. You want solid stranded copper not copper clad aluminum CCA for the wiring and a powerful enough alternator and battery to support the additional load. If your amplifiers are starving of power than they will never sound right. Crutchfield has many good articles and wiring sizing charts to help you select the proper size wiring. The length of wire and total wattage of your system will dictate the wire gauge size required. Also using class D amplifiers instead of class AB will demand less power from your electrical system because class D amplifiers are more efficient than class AB. Class AB though are still good amplifiers if you have the electrical current and space to support them and the amplifier is of good quality to.

    Set your gains correctly. Here again if this isn't done correctly you may either drive your amplifiers into clipping or not drive your amplifiers enough and under power the speakers. Improperly set gains will also have a noticeable effect on your sound quality especially if they are driven into clipping. Again Crutchfield has some good articles on how to go about doing this with a DMM. You're better off buying an amplifier that is more powerful than what is needed (about 125% of speaker RMS/nominal power) for your speakers than buying one that is smaller as you can always set the gains to put out less power and have more headroom in terms of power being available for those power hungry peaks in the audio waveforms.

    Lastly if you want the ultimate in SQ (but this isn't necessary) you can purchase a DSP such as the Audio Control DM608 or the Helix DSP. With these DSP's you can ditch your passive crossovers and run your drivers active but this is advanced stuff and if you do not know what you are doing you can blow some very expensive speakers like your tweeters in a hurry. Even for the advanced audiophile it can takes days of tuning to get it the way you like. You can also download a free software program called REW and purchase a mini DSP microphone for about $85 from Madisound to help you tune your system to at least look at what the frequency curve in your car looks like so you know what to do. I would recommend though that you start with all of the above and try REW before you dive into an all out active system with DSP or your likely to become frustrated and disappointed and spend a lot of money doing it too.

    There is one other way to go active on a budget and that is with a simple electronic crossover such as the Audio Control 2XS or EQX with equalizer. For example I used the EQX and LC2 I already had in my Ford F150 XL regular cab work truck on the factory radio to drive an old Alpine MRV F240 I bought used for $40. This amplifier of 40 watts a channel for each of the four channels is driving Tang Band 25-302SH 1" Neodymium Soft Dome Tweeters ($43 pair) in the A pillars and Dayton Audio ND140-4 5-1/4" Aluminum Cone Midbass Drivers ($62 pair) in the doors with astonishing accuracy and SQ that is better than the Focal PS165 components I have in my wife's Toyota Sienna. These are augmented with a cheap MTX XTL110P I bought used for $35 behind the seats and after tuning with REW just sounds fantastic for the money I spent on this system. I did use my JL Audio 8" microsub for a while and that combination sounded really good too but now its serving duty in my CX5. I also used light weight vinyl Sonic Barrier sound deadener in the doors that I feel is just as effective as the Second Skin Damplifier I use in my other cars but is less than half the weight. Like any good SQ system an experienced installer will likely tell you that a good amount of sound quality comes from the tune (speaker placement and EQ) and even a budget system can be made to sound better than a more expensive system with a bad tune.

    Good luck and I hope this helps.