car subs vs. HT subs

Discussion in 'Archived Threads 2001-2004' started by Brian Dobbs, Aug 17, 2001.

  1. Brian Dobbs

    Brian Dobbs Ambassador

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    Hi all. I want to know what your opinion is about the following plan I have. Instead of buying a powered subwoofer for my home theater, I want to use 12" car speakers instead and power them with a stereo receiver.
    I would take the sub pre-out of my 5.1 receiver into the left AUX input of a stereo receiver and then use speaker wire to connect two or more 12" car woofers. I also would like to build a box to stick the two speakers in, or buy a box.
    Assuming the resistance of the speakers match the outputs of the stereo receiver, is there any fault to this plan? Obviously this isn't the most ideal or easy way of doing things, but I just want to know if there is any objective criticism you can offer me as to why any of this doesn't present itself to be a good idea.
    thanks in advance!
     
  2. Rich Kraus

    Rich Kraus Stunt Coordinator

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    do you already have the driver(s) and the reciever?
    building a sub is a great idea, and a great learning experience.
    if you dont already have the driver(s) and the amp, we could probably recomend some if you give us a budget.
    ------------------
    'Till next time,
    Rich (the kite guy)
     
  3. Brian Dobbs

    Brian Dobbs Ambassador

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    I already have a stereo receiver (100w x 2). I do not have a 5.1 receiver but am not concerned about buying that at this point. I also do not have any of the speakers needed for my idea. I was thinking about building or buying a box, and purchasing two 12" subwoofers on sale for $79.99 a pair. I've never heard of the brand name of these speakers. I'm looking to spend either less than $100.00 on a pair of the speakers I just mentioned, or less than $200.00 on a "better" pair. thanks
     
  4. Dustin B

    Dustin B Producer

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    I can attest to the Tempest. One of these ran by both channels of your amp should slaughter any pair of $80 car subs. Provided you can do a large enclosure. 250-300L would be best but there are some guys here who have had favorable results with 140-160L Tempests.
    Just do a search for tempest or shiva on this forum and visit the shiva sonotube link you'll find at the top of the DIY forum and you'll be able to learn everything you need to know.
     
  5. Brian Dobbs

    Brian Dobbs Ambassador

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    What about this. Suppose I have four 12" speakers. Suppose each 12" speaker is 4 ohms and I arrange 2 of them in series to equal 8 ohms and place 2 for the right channel and 2 for the left channel. Let's say each speaker can handle 200 watts. Anything wrong with that?
    I want to clarify a few things. First off, I don't know much about speaker brands. Another thing, each of these speakers cost roughly 40 dollars each, not $80. I basically want to know if there is anything wrong with using car speakers for a Home Theater system.
    One more thing. Does the sub pre-out only send low frequencies to the subwoofer? I am asking because I don't know if powered HT subwoofers depend on a crossover to weed out the high frequencies or if the sub pre-out just sends low frequencies and no crossover is needed.
    thanks
    ps. i'll look for "tempest"
     
  6. Jack Gilvey

    Jack Gilvey Producer

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    quote: I want to clarify a few things. First off, I don't know much about speaker brands. Another thing, each of these speakers cost roughly 40 dollars each, not $80. I basically want to know if there is anything wrong with using car speakers for a Home Theater system. [/quote]
    If you'd disclose the make and model, you might get some more specific advice, of course. Since you pose a general question, I'll give a general answer: Yes, there's something wrong with it. Car speakers, especially $40 ones, tend to have a lot of output in the mid-bass, and rely on the enormous cabin-gain of a car's interior to provide deep bass. I would't use $40 car subs in a car, much less in a home. The Tempest is still a better idea and deal than four of them. No matter how many you use, they won't go any deeper. Adireaudio.com.
    quote: One more thing. Does the sub pre-out only send low frequencies to the subwoofer? [/quote]
    In a DD receiver, yes.
    [Edited last by Jack Gilvey on August 18, 2001 at 06:20 AM]
     
  7. Rich Kraus

    Rich Kraus Stunt Coordinator

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    jacks right. more drivers gets you louder, not deeper.
    if the drivers are not up to the task then the money would be better spent on one good driver. if the tempest is to pricy, or needs too large an enclosure for your room, try a shiva II. its basically a 12" version of the 15" tempest.
    same folks: adireaudio.com
    on the car subs, they arnt sutible because there "car" subs, but because of how there designed. like everyone else has suggested, be more specific on what your looking at and we can be of more help.
    ------------------
    'Till next time,
    Rich (the kite guy)
     
  8. Bob Ahlberg

    Bob Ahlberg Agent

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    Depending on the car subwoofer, you can build a fine HT subwoofer. If you want a direct answer to your question of how well a car sub will work, you have to talk about the specific parameters of the sub(s) in question. For some broader, more sweeping answers, read on:
    1. Generally, you get what you pay for. ANY subwoofer bought for $40 (unless you got it used from a very good friend) is going to be a fairly low quality driver...whether it's one meant for mobile use or HT use.
    2. HT driver "tend" to have a lower resonant frequency and due to several other parameters, "tend" to require a larger enclosure than drivers intended for mobile audio. Cars provide a significant "cabin gain" at frequencies below 50hz. A driver that is 3db down at 50hz in free space will be nearly flat to 20hz in a car, while that will not be the case in a home.
    3. Good drivers will work well in either environment. Examples: The Adire Shiva or the NHT 1259...both of which are high excursion 12" drivers. The NHT for will work well in a 3 cu. ft. sealed box, the Shiva in a slightly smaller sealed or a large vented one for HT use. In a car, either one will work well in a sealed box...the NHT in about 2 cu. ft. and the Shiva once again in slightly less.
    If you are determined to use the drivers you have...you'll have to provide the T/S parameters so someone can at least recommend the proper box for you.
    my .02
    Bob
     
  9. Brian Dobbs

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    Well, here's an update for you all. Maybe now this specific information can help with my descriptions. Today I bought two 12" Sony explod drivers as well as two 12" Kenwood drivers. Both pairs were on sale for $139.99 (for a pair). A few specs on each:
    Sony
    RMS = 200w
    peak = 800w
    range = 20 - 2,500 hZ
    4 ohms
    Kenwood
    RMS = 160w
    peak = 600w
    range = 25 - 800 hZ
    4 ohms
    The magnet for the Sony drivers were noticeably thicker and larger. This specs alone tell me that the Sony's are a slightly better speaker which means I probably should take the Kenwoods back and go buy 2 more Sonys.
    Now all I have to do is build separate boxes for these drivers. What type of wood would you recommend? And what do you think of my purchases? A sub that can get to 20 hZ is as good as you can get in my book!
     
  10. Manuel Delaflor

    Manuel Delaflor Supporting Actor

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    He decided on the car subs before entering the forum, all he wanted to confirm was if the "car" subs were ok for home use.
    I have a few comments. There are just speakers, not "car" speakers and "home" speakers. True, the marketing could be designed to make us believe that, but a speaker has only references with electrical signals and responses, not to if it's going to be on a car or our home.
    And the specifications he looked at are, almost, irrelevant to know how good are the speakers, the single most important factor to know if a speaker is up to the job or not is the Xmax properties...
    ------------------
     
  11. Isaac C

    Isaac C Stunt Coordinator

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    Sony XS-L1235
    Z = 4ohms
    Revc = 3.2ohms
    Levc = 1.2mH
    Fs = 23.5Hz
    Bl = 13.8T.m
    Qts = 0.39
    Qes = 0.43
    Qms = 4.9
    Vas = 104L
    Mms = 0.1753kg
    Xmax = 5mm
    Hi,
    The driver is not that bad, but its linear cone excursion is just TOO small for it to be suitable to HT use -- it simply is not capable of moving air. You can probably force the woofer's cone beyond 5mm, if clean bass is not a design factor.
    Moreover, two of these drivers in parallel to a single amplifier channel will just be too much load (unless each channel of your amp is 2-ohm capable). The only other safe way of connecting two of them to a single amp channel is by wiring them in series, which as you might already know has an ouput equal only to a single woofer of the same model -- not good [​IMG]
    Solution? Refund your money then spend it on a better driver such as an Adire Audio Tempest or two Shivas [​IMG] It's not too late yet, is it?
    I have two Pioneer TS-W303F 12" drivers and they can go down to 20Hz as well, but sound quality is nowhere near that of a single Shiva driver unit. If only Adire Audio's Australian distributor opened earlier, I would have avoided such inadequate woofers [​IMG]
    Good luck!
    Isaac [​IMG]
    www: http://www.geocities.com/f4ier
     
  12. Jack Gilvey

    Jack Gilvey Producer

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  13. Jack Gilvey

    Jack Gilvey Producer

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  14. AjayM

    AjayM Screenwriter

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    Now imagine what he could have done with 2 Tempests (same price $140 or $139.95pr and he wants 4 of those Sony's), will probably need a little bit more enclosure size, but it would put those car subs to shame (as Jack pointed out, he'd need 5 Sony's to one Tempest...for a dual Tempest, that'd be 10 Sony's). If you want to look at it in a value sense, to get the same air movement (need to move air to make bass)...
    10 Sony's - $139.95pr - 5pr = $699.75
    2 Tempests - $140.00ea - 1pr = $280.00
    Of course if you call Adire you may find they still have some B-stock Tempests laying around (in which case the price drops around $30 a unit)...
    As to the whole car audio/vs home audio for subs, you'll find some car audio subs will work very well in the home, I've heard of people have good success with Infinity, MASS, etc. But none of those come even close to your price range. I think I remember seeing TC Sounds comment that they don't build subs for "car" or "home" use, they build their subs to meet their specific goals (usually loud, deep bass), which can usually be worked into a car or home enviroment.
    Andrew
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  15. Brian Dobbs

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    I chose to go with car speakers instead of HT speakers because it was cheaper. I was going to get the cheapest ones available at Best Buy, but they were having a sale on these Sony's, so I said "What the hell". I demoed them plenty in the store and compared to the other subs they just seemed much better.
    You see, I think what I'm really going for is to be able to feel the bass and not concern myself with quality of sound. I just recently set up a home theater system for my DAD, and while designing it, we came up with some pretty creative ideas. After a week's worth of planning, argueing and configuring, we finally got a massive setup. The system includes a 5.1 receiver, a DPL receiver and a stereo receiver running all simultaneously. We take the coax digital out of the DVD player into the new 5.1 receiver, the RCA outs of the DVD player into the old DPL receiver, and the sub pre-out to an old stereo receiver.
    The stereo receiver accepts a mono signal and outputs to two 15" speakers located directly behind the couch. This creates quite a rumble. The RCA outs from the DVD go through a powered equalizer before getting to the DPL receiver. The DPL receiver utilizes our big screen television's speakers as it's center channel, and 2 pairs of L/R front speakers. One pair contains a 15" woofer with mids and tweeters, and the other pair contains 12" woofers with tweeters. The 5.1 receiver also has 2 pairs of front L/R speakers, which are set to "small" so more bass can be redirected to the two 15"s located directly behind the couch.
    The two 15" speakers behind the couch are actually bass guitar speaker cabinets from my dad's collection of cabinets in the basement. We know they aren't the ideal for a HT setup, and we know that bass guitar speakers are built differently than regular stereo HT speakers, but we had them so what the hell.
    I was very proud of this new setup and decided to start making one of my own. So I want to use "car" woofers for bass that I can feel, like the 15" speakers behind our couch.
    I made a little diagram of this setup, so if any of you would like to see it, follow the link.
    http://www.geocities.com/brianspageo...ometheater.jpg
    Personally, I'd put our setup against anyone else's anyday. Hell, I prefer watching movies in my family room better than in the movie theater itself. Granted, my tv isn't as large so there are just some movies you have to see in the theater, like the star wars saga.
    Maybe one day I'll actually buy a HT sub, but this is what I want to do now. These Sony's pack quite a whallop, and I'm happy with them. Now I have to make the boxes for them.
    What is Xmax?
    thanks for reading!
     
  16. Brian Bunge

    Brian Bunge Producer

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    Brian,
    I think you're missing the point here. What Jack and others are saying is that a single Adire Audio Shiva is going to outperform 3 of those Sony subs. Xmax is the one way linear excursion of a driver. So while your Sony subs are bottoming out a single Shiva will just be getting warmed up.
    You stated in your last post that you're looking for bass that you can feel and not necessarily quality of sound. Well, with the Shiva you can have both while with the Sony's you may have neither.
    Bottom line: You'll destroy those Sony's long before they outperform the Shiva.
    Brian
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  17. Jin E

    Jin E Second Unit

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    I can speak from experience since I have built subs using car speakers (a old JBL and a old JL-Audio) and a sub using a single Shiva dual voice coil 12” woofer. First off… the car subs did not have the Xmax to move enough air to extend down to 20hz. Heck… I couldn’t get them to extend down to 30hz. Modeling the JBL in several different scenarios I decided on a 2.5ft^2 enclosure tuned to 46hz. Added a second JBL only increased my SPL not the performance below 40hz. I built two subs [email protected] and took some measurements. I got a good response from the system, with my sub response flat from 100hz down to about 35hz (-3db) corner loaded with a -3db dip at around 55hz. Yes… I was happy. There was plenty of bass and it did quite well for music and the occasional LFE for movies. Two subs gave me plenty of SPL and I though it sounded damned good…. Until one day…
    I helped build a sub with a 2ft^2 sealed enclosure using a single Shiva driver. I measured the sub against my e-cheapo JBL subs and it blew both of them them out of the water. The single Shiva in a SEALED enclosure got us down to 29hz measured ANECHOICLY!!! With in room response we were able to get clean usable SPL all the way down to 20hz. This thing ROCKED… and WAY outperformed the two JBL subs even if you compare the sealed shiva anechoic to two JBL’s corner loaded. The single shiva was also much more efficient then the JBL subs. The JBL’s had a Xmax of around 6mm. They were pretty nice car speakers, but when it comes t o moving air Xmax is king and that’s where you are going to lose out with your Sony and kenwood. Do yourself a favor… return those subs and get a single Shiva dual voice coil. Why settle for a Honda when you can get a Supercharged Dodge Viper? Last time I checked the Shiva was around $115. Run each channel of your receiver to each voice coil of the Shiva… that way you use all of your amplification you have available.
    ------------------
    -Jin
    My Theater
     

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