Pickup Truck Bed Audio System: Can this setup work?

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Pickup Truck Bed Audio System: Can this setup work?

  • I own a 1997 Chevy Silverado with an extended cab, no third door. My factory speakers are starting to fade and I plan on replacing all the factory speakers and the stereo. Since I am doing this, I thought I would try and make my truck unique while I'm at it; seeing as I am younger and still have quite a disposable income. I want to be able to play music outside my truck cab during bonfires and such. I enjoy old country and bluegrass.

    I would like to build an enclosure with two 6.5" two-way speakers and a sub (10"-15", unsure yet). I would then take a 4-channel amp (75 watts RMS x 4 at 4 Ohms), bridge 2 channels to my sub (240 watts at 4 Ohms), with 75 watts RMS being sent to each of the two 6.5" speakers.

    The trick is that I want to be able to attach the enclosure in the bed of my truck and also have the ability to detach it from the bed and use it inside the cab, without any more hassle than disconnecting simple wires and moving the enclosure in and out.

    My idea was that I would drill a small hole out of the back of the cab, passenger side because the seat slides far forward. (I plan on removing the standard emergency kit box from the backseat floor). I would then drill a matching hole through the front of the bed, creating two identical holes parted by the midgate. I would then cut a piece of stainless steel Flex-Tube to connect both holes, weather-shielding wires that would pass between the cab and the bed. I would then run speaker wires (size doesn't matter at this point I don't think), from the cab to the bed. These wires would be ran up in between the plastic bedliner and the metal frame, ending a reasonable distance into the bed in-case I would need extra wire length. I would fabricate some sort of weather-shield for the ends of the wires. These wires would remain permanent to this location, saving time on feeding wire every bonfire or occasion. I'd then keep shorter wires inside the truck cab, that would attach from the amp (now located where the emergency kit box was previously), to the enclosure sitting in the back of the cab. The truck bed wires would then be unattached to anything while the enclosure is attached to the amp inside the truck via the short wires. Vice versa when the enclosure is attached to the truck bed wires.
    This amp would only be powering this enclosure, and not any of my interior speakers.

    I would also like to ask if there is any way I'd be able to switch between my interior setup and the enclosure running off the amp? Like flip a switch that would turn my interior speakers off and the amp (enclosure) on? And possibly even allow both to run at once, while still being able turn one or the other off? Don't know if I'm asking too much or not. I'll take any advice I can get, but please, if all you are going to do is tear apart more than half of my idea, don't bother responding.
    I'm new to vehicle audio systems, so bear with me if you read all of this to simply tell me it can't be done. I'd appreciate being told as to why it can't be done, so that I may tweak it or come up with another idea before I start spending money.

    [edited by: Paul at 5:40 PM (GMT -5) on Thu, Mar 29 2012]
  • Interesting concept. Well, running the interior speakers off the HU and the two 6.5" speakers and sub off the amp separately or together would be pretty easy to do. Since you don't have the HU yet, look for one with at least two sets of preamp outputs (one of which is for subs) that is able to have the internal amp shut off. This would easily allow you to turn your trucks interior speakers (that are being powered by the HU) off. You could also wire in a simple toggle switch in the remote turn on lead to the amp that will allow you to cut power to it. Doing this should give you the option of running the interior speakers by themselves, with the two 6.5" speakers and sub, or not at all. Same goes for the amp if a switch is placed on the remote turn on lead.

    As for how you're speaking of setting the system up to allow you to power the enclosure inside or outside of the truck seems like it'd work, but you'll have to be very carful that you don't accidentally leave the wires hooked to the amp that are not currently connected to the enclosure. Also, although you've already stated it, you'll have to find a way to protect the wires that will be left in the bed of your truck from the elements.

  • How exactly do the preamp outputs work? I've looked into it a bit, but I feel like I'm missing something. The preamp outputs send the signals to the external amp, from what I've read. Are the signals being sent from the HU to my interior speakers the same as the ones being sent out the preamp outputs? In other words, if I send the rear preamp output to my sub and the front preamp output to the 6.5" speakers, would my front door speakers be playing the same sounds as the 6.5" speakers in my enclosure?

  • In this scenario, your vehicle front speakers will be powered with the speaker outputs of the head. The rear preouts will be set to 'sub' if there are only 4. You could get a head with 2 front, 2 rear, and 2 sub preouts. (6 way RCA preamp outputs)

    Does that answer the question ?

    GLH Geeked

  • Sorry, yes, the full-range speakers in the enclosure would be playing the same as your front speakers in the truck. Not the best option, and poor advice on my part. A receiver with front, rear, and sub preamp outputs is really the best option and they are quite common. Factor in you'll be wanting one that has the option of turning off the internal amp and I believe you'll pretty much be left with HUs that have 3 sets of preamp outputs anyways. It's been a while since I've looked for HU's with the option of turning off the internal amp, but I know Alpine has had that feature in their HU's for some time. Pioneer has had it in the past and I've seen Kenwood has had it in many of their upper level HUs too.

  • The amp I'm looking at (Sound Ordnance™ M-4075) has two preamp inputs, front and rear. The rear would  take the Sub output from my HU as I understand. Seeing as my only option is getting an HU with 3 preamp output sets, would I be able to take the Rear preamp output, and put it in the Front INput on my amp, thus allowing my 6.5" enclosure speakers to play what would get sent to my rear interior speakers?

    I'm asking out of curiosity, to better understand how these things work and what tricks there are to them. I'm pretty sure I've found a Kenwood that will fit the bill, and the budget, for a HU. Kenwood KDC-448U. Had you not given me names of brands that you know offer an internal amp on/off switch, I would have had to search Crutchfield's entire stock of receivers. So thank you.  GLH, it helped but it seems Weigel21 is finding a better connection with what I'm asking for. Thanks though.

  • Yep, you can use the sub and rear preamp outputs on the HU and connect them to the amp.

    Now since I don't know what speakers or sub you plan to get, I can't say much about your amp choice. The 3 year warranty is very generous and I've heard good things of the SO line of products (given a person is looking for a good bargain product). However, there is no evidence that the amp can truly pump out it's rated power. I'm not saying it's a bad amp, but if you buy it expecting it to pump out every bit of it's claimed power you may not be getting what you paid for. Then again, it may very well pump out every bit of it's claimed power. 

    It is a class AB amp with 60AMPS of on board fuses. The typical efficiency of class AB amps is around 50%. Given this, the amp could only pump out around 215RMS to your sub and maybe something around 60RMS to your speakers. For it to pump out it's claimed power it'd need to be at least 56% efficient, which isn't a stretch by any means, but we haven't any proof it happens to be so.

    Now no matter what amp and speaker/sub combo you end up with, be sure to set your gains properly on the amp. You can follow this method for setting the gain with a DMM.

    If you do end up buying that SO amp, I'd probably try shooting for limiting the output of the amp to an output I feel the amp is sure to do, such as 60RMS for the 6.5" speakers and 200RMS for the sub. Keeping all this in mind, I'd look for speakers and a sub that would perform well of that amount of power.

    If you push the amp beyond it's capabilities by setting the gain too high you'll feed the speakers and sub a clipped signal. There is a link on the page for setting the gain that goes into detail on what clipping is and there are links to test tones for setting the gain as well.

  • I don't think I'll have my speakers picked out anytime soon. I won't be doing the enclosure/amp set up until summer, but I'd like to get my project list done so I know how much this is going to cost once my paycheck rolls in. Anyway, right now I'm stuck between a Kicker 10C154 Comp 15" 4-ohm subwoofer and a Kenwood KFC-W3013PS Performance Series 12" 4-ohm component sub. I've heard extremely great things about Kicker's subs, but I have a friend who has Kenwood subs that sound pretty good but are way underpowered. Which one would be best for my single sub setup? enclosure is gonna be sealed. Again, I listen to bluegrass and country music so I'm not looking to shake my truck down, just want to be able to feel the bass a bit and hear quality low frequencies. If you have a subwoofer that you feel would work even better with this setup and is under $175, please share.

  • From what I hear (not personal experience) kicker subs tend to perform better in ported enclosures and are more SPL subs rather than SQ subs.  If you are going to mainly listen to country/bluegrass I would recommend a sub thats better suited for sealed enclosures.  Hopefully someone can chime in for suggestions, but in your case kicker wouldn't be my 1st choice

    1998 Honda Prelude, Pioneer DEH-P9400BH + Sirius tuner, Kicker KS6.2 front components, Kicker KS6930 rear speakers, Alpine MRP-F300 for speakers, Alpine SWR-1022 in ported box, Rockford Fosgate Punch 501s for sub.

  • Actually, Kicker is probably 1 of the better choices for a sealed box.

    The Kenwood is less sensitive, but will work in a much smaller box, and handle more power.

    6x9 speakers would be a better choice than 6.5" for the full range part of your idea, but I would not mount either in the same box as the sub. Consider making small ported boxes for them.

    any of these would be great - http://www.crutchfield.com/App/Product/CompareTo.aspx?compareItems=01|500SPS609&compareItems=01|113KF6983P&compareItems=01|113KC6984P&compareItems=01|113KFC6993&compareItems=01|206KS69&compareItems=01|1089632CF&compareItems=01|113KFCX693&compareItems=01|206KS693&compareItems=01|107DB691&compareItems=01|107DXI690&compareItems=01|1089633CF&compareItems=01|107MM691&compareItems=01|1086929I&compareItems=01|500SPR69&compareItems=01|1086939I&g=52300

    amp to work well with 6x9's and the Kicker Comp 4 ohm 15" - http://www.crutchfield.com/p_777M4100/Sound-Ordnance-M-4100.html?tp=35782

    amps that might work well with 6x9's and the Kenwood KFC-W3013PS 4 ohm 12" - http://www.crutchfield.com/App/Product/CompareTo.aspx?compareItems=01|114D6004&compareItems=01|113X600F&g=347050


    GLH Geeked

  • Actually, given the type music you listen to and you don't really care about low bass much, you might rather have 4 6x9's in ported boxes with a 100 x 4 amp. They easily reach down to 60-80 hz and can really put out the volume. A sealed sub system is not going to be real loud out in the open like it can be inside a vehicle. 4 6x9's can be set out pointed in 4 different directions or all the same and really play loud. Would also be easier to move in and out of the cab. Easier on the battery and alternator, also.

    GLH Geeked

  • I'll try not to cut out more than half of the idea, but ...

    Okay - I got to this thread a little bit late, but before you go cutting up your truck, is there any reason either of the following wouldn't work for you:

    • Mount the amp to the enclosure (usually not recommended, but okay) - run long M-F RCA's from behind the HU and long M-M RCA's from those to the amp.  When you are at the bonfire, put the enclosure in the bed and run the RCA's out the window to the amp.
    • Mount the amp in the car, but run really long speaker cables with quick disconnects (like a trailer wiring connector, but other options could work) to the enclosure.  At the bonfire, unplug the Quick-disconnects, put the enclosure in the bed, run the speakers wires out the truck window and plug the quick disconnects back up.

    Either option seems much simpler than what you proposed - both from a ease of accomplishment, cost, re-sale of the truck and reliability of the truck standpoint - although with the hassle of having to run wires out the window at each bonfire.

    Also - just to clarify:

    • You only want to amp the enclosure, not the interior speakers.
    • You want to be able to play the enclosure in the bed, with or without the interior speakers playing also.
    • You don't see any plan where you would want the enclosure and the interior speakers playing inside the cab at the same time, or just the enclosure playing inside the cab

    Is all of that correct?  (I'm not sure it matters, but it helps to know what you are after.

    Final comment (until you reply) - I like the idea of running the enclosure off the RCA's and the internal speakers off the HU internal amplifer - it isn't the only way to do it, but it simplifies some things.  Assuming you go with this method, you don't HAVE to have a HU with a setting to turn off the internal amp - you could do it with a toggle switch on the speaker negative wires - you would need a 2PST switch for one pair of speakers and a 4PST (usually rotary) switch for two pairs.  That gives you a LOT more HU choices (basically anything with at least one pair of RCA's.

    Following up on GLH's last comment - it's also a good idea to use a separate battery with an isolator for this system so you can still start the truck with the starting battery if you fully discharge the auxiliary battery.

    Hope This Helps!!!

    Anyone else have suggestions?

    [edited by: TigerHeli at 12:07 PM (GMT -5) on Tue, Jan 24 2012]

    2002 Ford Focus JVC KD-A815 Sony CDX-GT410u Sony XT-100HD HD Tuner Stock speakers, no amp, no subs

  • TigerHeli:   I really like your idea of running long speaker wires out the window, although I'm quite certain I'll be driving this truck til its death. My amp is gonna be right below the right rear-side window, which is a vent window. I could run my enclosure(s) inside, with the speaker wires wrapped up a bit to prevent entanglement, and then unwrap them and put them out the window.  As for the quick disconnect idea, don't you need to have two separate wires in order to create a male and female connection? Would it be simpler to just have naked speaker wire connected to the amp and then pin connectors or banana plugs to the enclosures? I plan on putting speaker terminals on however many boxes I eventually settle with, so would that then defeat the purpose of Quick-disconnects?

    As for the HU setup, unless I decide to settle with the 4 6x9's as last resort, I think I'll stick with the HU that has the internal amplifier on/off setting just for simplicity sake.

    GLH:   I DO want to be able to run my enclosure inside the truck with my interior speakers. I don't know if any of you enjoy modern bluegrass, which is what I mostly listen to. While it may not have continuous subwoofer-worthy beats, I feel it has enough bass that having a sub would bring out those bass notes that usually overbear my internal component woofer. I would have the enclosure(s) inside the truck most of the time, so I feel the sealed sub would be my best choice. If that means my bass will be a bit lacking when playing at a bonfire, I suppose I'll have to live with that in order to enjoy my music during winter, spring, and late fall, seeing as we don't have any bonfires during that time of year.

    Now that I've further explained my intentions with this system, I'd like to ask questions.

    GLH:   What exactly is the difference between 6.5" speakers and 6x9's, besides size of course. Is there frequencies one or the other is better at producing? As long as the 6x9's aren't stealing <125 Hz from my subwoofer, and would better play mid and high frequencies than 6.5", I'm totally for them.

    I gotta be honest. If all of this requires me to spend a bunch more money and time on an extra battery, I think I might give in to the 4 6x9's. Could you further explain what a separate battery with an isolator (don't know what that is) and what such a set up would cost? 

  • The isolator cost would just be the cost of a (preferably) deep cycle battery and an isolator switch. It is so the amp will run off the deep cycle battery while the truck is sitting and not running and then you will have the main truck starting battery still charged. The truck alternator will charge both batteries when the truck is running.

    The 4 channel amp will draw about the same current powering 4 6x9's as it would 2 6x9's and a sub.

    6x9" speakers will play lower and louder bass than 6.5' speakers, (all factors the same) are very good with mid-bass, and will handle more power. Alot more cone area. They can play all the bass passages of bluegrass music. A subwoofer can play the same bass louder and with more depth. Your full range speakers, whichever size, will likely be highpassed around 120 hz and the sub lowpassed around 80-100 hz.

    I am gonna say a good set of 6x9's will play 80 hz and up loud and with no problems. A good subwoofer  system will play 35-100 hz very well.  

    I am not trying to talk you out of a sub system. A good sub system will bring out the low bass of any type music. As a musician, I think the lowest notes in bluegrass will be from the acoustic stand-up bass. It is usually not a very prominent sound in bluegrass, but is noticeable, and the bass player definitely hopes so. I believe it to be more of a mid-bass sound than a low-bass sound, but a sub can really define it, if that is what you want. 6x9's can play it well also. 6x9's will be alot more portable.


    GLH Geeked

  • If its not too much messing around, I suppose I'd be willing to put in this extra battery. I haul wood during the summer and I suppose it'd be nice to keep the truck off and just listen to the 6x9's on top of my bed-box while working outside the truck, splitting and stacking. Background music to keep me sane. 

    Again, although the quad 6x9's would be more portable and potentially louder for bonfires and working, I think I'm gonna put my interior listening experience before that. I think I might have exaggerated the need to listen to music outside of the truck. I want a sub to define the upright bass. You said the Kicker would be best for a sealed box (unless there is a sub that you think would be even better for my specific situation), so I think that's what I'll get, along with the SO 100W x 4 amp you recommended with its use. While I wait on TigerHeli's wiring response, what would you say is the best option for two 6x9's, 2-way or 3-way? I've also heard that metal tweeters sound better for outside use, like convertibles and other situations that have quite a bit of unwanted noises. Is this true? Or should I just stick with 6x9's with softer tweeters?