Clueless About Sub Setups

munch562munch562 Posts: 1
edited February 2008 in Car Subwoofer Talk
I have a 96 toyota avalon was thinking about installing a sub and amp. I am leaning towards getting 1 10" Alpine Type R and putting it in a bandpass enclosure but i dont know the difference as to which is better dual 2 ohm or 4 ohm. I dont know how to match the amp either the sub cranks out 500w RMS and 1500W peak power am i supposed to get a 1500w amp or just one thats 500w RMS. And do u just match 4 ohms to 4 ohms or is it different? Gonna buy everything off ebay just wanted some help and to hear some opinions. What kinda enclosure would u recommend?
Post edited by munch562 on


  • ilikesoundilikesound Posts: 355
    edited February 2008
    why not just walk into best buy? you can find the same stuff there. make sure your amp can handle 4 ohms, as well as your subs, match them.
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  • MarcLazarek78MarcLazarek78 Posts: 68
    edited February 2008
    If a single,I'd get a 15'' sub and port it,and you'll have TONS of bass (at least for the money:bass ratio) Find a Sub where you can look up on their website or call them and find out what size/specs of a box you need to build. JL audio has that right on their website and have been the best subs for the 90's and possibly still.I would look into Polk subs also. A ported box will give you louder bass but not as tight/responsive. A sealed box will give you longer speaker life and the tightness and responsiveness that you want when you listen to music with fast double bass drums. Entry lvl subs are just fine,as long as you get the box volume correct!And use 3/4'' plywood (or MDF) and gorilla glue all the joints plus the normal wood screws you would use. JL and Polk are the only two I would look into and at their websites,then try and compare sounds and pick.(considering the sound tests are from the right enclosures for each speaker sealed and ported. but your probly not going to find a display like that.)

    Ohms are the measurement for resistance,so you don't blow anything up.

    Speakers come in 4 ohms mostly. Speakers also come in 8 ohms.

    Speakers also come in DVC which is essentially 2 speakers (voice coils) driving the same cone. Thats why they have 2 pairs of speaker terminals.I'm not fluent in DVC tho.I suppose they could have one set of terminals,or two sets bridged,or two sets incise you wanted to send separate power lines to each.

    Back to the resistance ohms. when you connect two 4 ohm speakers together,this drops the resistance ohms in half,causing a 2 ohm load.if you did this with 8 ohm speakers it would cause a 4 ohm load.
    hence a DVC 4 ohm speaker. Why do they do this? I'm not positive,but I imagine with DVC that speaker cone is being pushed a lot harder,or more acurate by not one, but two voice coils.

    The Amp. Most if not all amps these days are 4 ohms constant,and 2 ohm stable,which means you can put a 2 ohm load on them. when you do this you almost double the output it was putting out at 4 ohms because your lessining the resistance and allowing more power through. SOOOOO, if your amp is 75w x 1 @ 4 ohm (a single 75 watt channel at 4 ohms) and you connect two 4 ohm speakers to it,the amp will be pushing out about 125 watts,and each speaker will get 62.5 watts. regardless of what wattage rating the speaker is.

    two 8ohm speakers will present a 4 ohm load and the amp will push out its rated 75w @ 4 ohms,and each speaker will see 37.5 watts (half the suppled wattage)

    now lets say you have an amp that is 1 ohm stable and rated at 75w x 1 @ 4 ohm. and you connect EIGHT 8 ohm speakers to it knowing that an 8 ohm speaker and a 8 ohm speaker create a 4 ohm load, so you do this twice and connect those 4ohm loads together and create a 2 ohm load. thats 4 speakers at 2 ohms,and do that twice and connect those together, yep,8 speakers at a 1 ohm load.You would have to do the math to figure out how much power each speaker was getting, but you wont be blowing anything up.

    Those big guitar amp stacks you see with 2 cabinets stacked and the amp on top, use 4 16 ohm speakers per cab,and present two 4ohm loads. one cab at 4ohm connects to one 4 ohm channel on the amp and the other cab a 4ohm load to the other 4ohm channel.

    When picking an amp out,you're looking at what wattage it puts out at RMS,and not the MAX wattage. RMS is what it puts out continuously,and the max is what it puts out when it peaks.

    If your getting just one sub a DVC might be better because it seems you would be able to get your 4 ohm amp to see a 2 ohm load and put out more power to the sub/cone. However I am not entirely sure how that works and thats what I would ask someone else about.

    A bandpass enclosure is just that, it lets certain frequency bandwidths pass and others to not.(which you can also accomplish with a simple crossover circuit)

    Ported enclosures require tuning also but let it ALL go.(which you can also use a crossover circuit with)

    Both are more difficult to build than a simple sealed box,and should be built to the speakers exact specifications. Your taking a big risk with your success and sound quality just throwing any speaker into any ported/bandpass enclosure.

    Building your own box is 1)cheaper 2)exact 3)custom 4)good work is its own reward.
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