Is this idea any good?
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New member Username: Bdb_86Post Number: 5 Registered: 12-2003 | i have been trying to do somthing different in my new car i have been trying to do somthing with 8" speakers but i dont have alot of money and i dont just want to put them in the trunk. so far i have just 2 8" crunch usa subwoofers in the 6x9 whols witch i am not plaining on sticking with and i have a third in my room but i am looking to put a bandpass box between the whols and put the ports through the rear deck in my car and then put 2 6 1/2" speakers as mid and tweet in the 6x9 hols is this a very good idea if not what could be better i like the true sound of an 8" speaker so i would like to stick with that + i have never seen a bandpass box that holds 3 speakers |
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New member Username: GlasswolfPost Number: 403 Registered: 12-2003 | try using a single 8" sub in a 6th order box, or a transmission line box if you want to do something really different. see what you can squeeze out of one 8" instead of three.. either box will be big, so you'll need the room anyway but when people hear it they'll never believe it's only a cheap 8" if ya build the box right. heh 6th order bandpass: http://www.diysubwoofers.org/bnd/6thorder.htm transmission line: http://www.diysubwoofers.org/tls/ |
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New member Username: Bdb_86Post Number: 6 Registered: 12-2003 | hey man thx for not just telling me what to do but actuly sending me links you have been a big big help thank you i think that i am going to go with the 6th order i have enough room that i am going to toy with this and were the air ports are i am going to try running tubes from there to under my back seat so that the sound from them well go into the car not just around in the trunk but i am just fooling around see what i well get thank again it an old car with spring seets well you should get the idea it might be dumb but lets see what happends (its like how bose does there stereos) |
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New member Username: GlasswolfPost Number: 412 Registered: 12-2003 | just keep in mind that if you make the ports external, calculate for the change in internal box volume for the lack of ports inside (otherwise you subtract their air volume from the box volume along with driver displacement) and if the port lengths are altered, this alters the tuning frequency. it's tricky to do what you're saying, but I've done it before.. it's possible.. porting through the rear deck. |
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jay amaro Unregistered guest | listen to glasswolf but one thing to consider and you can probably achieve better fills including midbass by putting the 6x9's back, using very high quality front speakers and not over driving the interior speakers by turning down the bass (let your subs handle the bass responce and not try to force your interior speakers) so when you turn up the volume they are using all their power to produce higher frequencies and im assuming since you have the 3 8" crunch's that you also have an amp for the box that will hold. if you have everything then all you need is a box, i would stay on the link glasswolf sent you and decide what kind of bass you want based on the type of music you mainly listen to and choose a box that gives the best bass type for you. if your amp is 2 channel (with a xover)then id use both 8's and if it can go 1 channel and down to 2 ohm then id wire the 2 8's into a 2 ohm load and use them to make bass like they were meant to but not through the 6x9 holes in your rear deck because youll lose 2 sources to transmit mids and highs into the car. if you provide me with the parameters for your crunch subs i can design a bandpass box for you which will produce alot of bass but only within a very limited range and you will need the 6x9's to fill in where the bandpass will fall off. the bandpass is a very complicated and tricky design and will either be right or wrong with very little room for error like with a sealed box and to some degree a ported box. anyways i can help you but i need more info. thanks, jay p.s. if ultimately all you need is a box and wish to spend very little id use a ported box but a sealed box would be even smaller and require less materials just some things to keep in mind. it should be about the same in your area but lowes has 3/4 mdf sheet 4x8 for about 18.00 id use liquid nails subfloor adhesive for both a box sealer and on all joints for strength but this is in addition to screws. drywall screws 1.5" to 1.75" 1 lb. box speaker terminal cups from radio shack or your local audio shop and im not sure how much you want to keep costs down but without any covering your box could be had for about 30 or so in that ballpark but with carpet, corner protectors, grills, handles then a bit higher but it depends on how fancy you want to get. also remember if you do use a ported or sealed box make sure you use a divider between both speakers (although one would be just fine too) not only to stiffen the box better but also to isolate the speakers. |
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New member Username: GlasswolfPost Number: 422 Registered: 12-2003 | just to add some clarification to that bit about powering the eight(s) if the amp is 2 channel and it can be bridged, you can bridge the amp and run a 4 Ohm load on it (probably means one sub.) if you run one sub on each channel, you'll be getting a stereo 4 Ohm load, which isn't too ideal of a load. Ultimately, you could use a mono sub amp (non bridged) and wire two 5 Ohm subs to that. then if ya really want to have fun, if you go 6th order, you can use two of the subs in a clamshelled isobaric setupo in the box to increase the efficiency. just be sure you calculate for that change and the change in displacement when doing so. it'd make for quite an amusing box, to say the least. |
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jay amaro Unregistered guest | very true but a isobaric increases efficiency for the box size but also in the clamshell setup the they should be phase inverted to each other and the power requirements climb but enclosure size efficiency does get better in isobaric but power efficiency decreases. and if the subs are isobaric but placed inline with each other then the should be wired in phase. but i think he said he didnt want to spend alot so i didnt want to suggest and amp and i wonder if he already has an amp even? yeah thats right i missed that and he wouldnt want to run a single 2ohm into the amp bridged because yeah most likely it is a bridged 4 ohm load but that was my fault i wanted to add that he can use all 3 subwoofers and use a series/parallel combination using all 3 4ohm subs and come up with a 6 ohm load to put into the bridged amp. i wanted to add that earlier but forgot but that would be a way to use everything he has without spending anything and well assuming he has an amp that can be bridged. and to get really interesting in the series/parallel set up it could be a ported and sealed configuration maybe: one long box with the two series wired subs in a sealed box and the final paralleled sub in a ported box and then he can use all 3 8's in one box and have both a ported and sealed set up and all that into a 6 ohm load and using one amp and one channel. just another idea to use what you got. jay |
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New member Username: GlasswolfPost Number: 441 Registered: 12-2003 | yes clamshell, the mechanical Q alters. The sealed side of the enclosure will decrease in volume, and efficiency will increase because you'll have two subs moving the same mass of air. This works to his advantage all the way around since he has the two subs already and space isn't a big issue. of course, when using two subs in this configuration you will need to invert the phase of *one* sub so that they move in the same direction together instead of fighting each other. as for an amp.. I sure as hell hope he has some sort of amp! you sure aren't going to run any 6th order subs off of a head unit!  |
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jay amaro Unregistered guest | lol yeah thats true i do hope some kind of amp will be running whatever box setup especially 3 8" subs. yeah this should be a pretty cool looking and interesting arrangement. keep us posted. jay |
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New member Username: Bdb_86Post Number: 8 Registered: 12-2003 | ok forget any thing that i seid before this is what i need now: i have a crunch usa 8" P8304 speaker and i am looking to make a sealed box for it but i dont know how much air space it needs and i dont feel much like playing around with box sizes if any one knows please fill me in |
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New member Username: GlasswolfPost Number: 480 Registered: 12-2003 | 8" sealed? 0.6cu ft should be fine. |
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