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New member Username: SakuPost Number: 2 Registered: 12-2003 | ok here is the dememsions of my sub box im building: ported 1.65 cuft with 2"diameter port x 6.5" in depth. but how many holes do i drill for the ported part? im assuming only one on the back of it, but what does it mean by "6.5'' in depth"? how can the thing be 1.65cuft and 6.5'' deep? |
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New member Username: GlasswolfPost Number: 402 Registered: 12-2003 | umm ok first, what are the subs? 10"? 1.6cu ft is a bit too small for most 12" subbs for ported. also a 2" port is going to suck. literally. you'll get port whistle. you need at least 3" ID for 10" subs, and 4" ID for 12" subs. 6" ID for 15" and larger the length of the port(s) combined with their diameter are what determine the port frequency for the box. This is the frequency where the box will peak in efficiency. |
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jay amaro Unregistered guest | if you tell me all the parameters of the sub you have i can use my software to plot the ideal box size and port size and length for you. jay p.s. oh yeah by the way the more ports you add the length increases each tube. ideally one would think if you needed one 6.5 inch port tube length then by adding a second port tube then that length simply gets cut in half right? wrong! generally for each additonal port you add the length multiplies almost in proportion (in your case 1 port=6.5 inches but 2 ports=13.5 inches or so) and the larger the port opening the longer the port length needs to be also and the smaller opening is generally a shorter tube. so i would go with just as many ports as you need and use the size recommendations glasswolf pointed out but also let me know what you will be using for port tubes, i.s. pvc pipe, hose, premade port tubes?? if you provide the diameter i can calculate the length also as another option i can calculate a square port opening and depending on your skill level in carpentry you have the option of building a square/rectangle port opening into the box design. a bass slot if you will. i have some customers who like this alot better due to the hidden and custom look but when thats done it becomes very specific to the driver used and any future driver changes makethe bass opening unmatched to any other driver so keep that in mind. |
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New member Username: SakuPost Number: 3 Registered: 12-2003 | hey Jay, ok so the parameters are: overall depth 5.53'' and mounting depth 4.92'' overall diameter 12.09'' and mounting diameter 10.83'' and as for the material i will be using for the port tubes i have no idea.....Iam a total noob iv only made one other sub box befor and it was all straight forward, i just made a perfect cube(all the right dimensions of course.) so pleas walk me through this step by step. firstly what do u recomend for port tubes and which side of the box do i put it I.E top, bottom, back? do i have any of the tube stick out of the box? and yes i should have no problem building a square port if i need to but what would i use for the port tube? againg i am a total noob so i may need carfull detailed instructions. thanks colby |
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jay amaro Unregistered guest | hi colby, ok im sorry i should have been more specific ill be needing a little more information about your sub or subs. ok what kind of car is it and how much space do you have for the box? do you have room for a larger box? what kind of amp? will you be using 2 channels or 1 and .5, 1, 2, 4 or 8 ohms? does your amp have a built in xover or do you have a seperate electronic xover or will you be using a filter like fmods or a passive xover? and most importantly i need more parameters on the subwoofer like (vas, qts, xmas etc.) if you got the sub/s new then a sheet should have come with it and if not then i need the exact brand and model and size of the subwoofer and i can look up that information for you. as for ports you can either buy ports already made like aero ports and places like www.crutchfield.com or http://www.thezeb.com/caraudio/lightningaudiosubboxaccs.html sell port tubes and pvc pipe works also although i try not to use them when i can help it but they do just fine especially to keep cost down. if you must use plastic hardware store pipe i would go to like lowes or home depot and go to the section for garbage disposals and get a waste pipe from a garbage disposal hook up kit because that plastic pipe has a flange and makes for a cleaner and better install for a port that a straight piece of pipe and looks better. |
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New member Username: SakuPost Number: 4 Registered: 12-2003 | hey, ok i souldnt have any problem with the box size as i have quite a bit of space for it. and the amp is usa acoustics 2 channel 4 ohms. i have a separate electronic crossover 8 channel and the diameters of the sub are: power 500 watts impedance 4 ohms magnet structure 80 hz 45.4 oms 1.55 qes .087 qts 0.56 spl 89.0 vas(cu ft) 1.745 hopfully thats every thing ttyl colby |
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jay amaro Unregistered guest | hi colby yup that should just about do it or ill do the best i can with the information you provided but i am curious is this a dual voice coil sub? was it a typo or is the ohm load really 1.55 and on a voice coil thats very possible but if its a 1 ohm v.c. then i know that the amp will certainly not handle that and 2 ohm is hard enough on an amp but when you get into 1 or 1/2 an ohm thats sure to kill any amp. oh yeah what size and brand of sub is it? thanks, jay |
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New member Username: RedskinPost Number: 16 Registered: 12-2003 | Hi colby, have you actually got a sub for this box or is it hypothetical? Having modeled this subs numbers on my design software using a ported box seems a bit of a non starter. You seem to get better results using a simple sealed box.Anywhere from 3/4Cu Ft upwards. If your feeling clever go bandpass to get your response down lower or really clever and go for Glasswolfs fave the 6th order bandpass. Looking at the specs of your sub the Fs of 45hz is really a bit to high to make a really good sub with good low bass. |
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New member Username: SakuPost Number: 5 Registered: 12-2003 | hey guys, ok firstly the 1.55 oms the ''o'' is acually a ''Q'' so its Qms=1.55. and no its only a single voice coil and its 4 ohms and also i forgot to add the voice coil is 1.5 the brand is pyramid and its a 12'' and now secondly yes i do have a sub for the box im makeing. and as redskin says ''45hz is really a bit to high to make a really good sub with good low bass'' ya i was kind of expecting this sub to be NOT top of the line in performance measures, its a really cheap sub for a really cheap truck. This sub is almost just a starter for me so i know how to do all this stuff the next time make a box. so if u guys who have software could tell me the way i can get THE BEST possible performance out of this sub that would be great. colby oh yea and what does redskin mean by ''bandpass''? (im a noob) |
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New member Username: RedskinPost Number: 17 Registered: 12-2003 | To see what I mean about bandpass boxes check out www.diysubwoofers.org for whole heaps of info on groovy boxes. |
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jay amaro Unregistered guest | ok for starters redskin left out alot of critical information you would need to know. what he means by bandpass which is the type of box basically where the subwoofer is in the middle of the box and fully enclosed within the box design. there is a front and back chamber and both chambers are ported (i.e. 6th order bandpass) but this type of box design is very complicated and also quite large and unless you have plenty of room and also want limited bass performance. after carefully considering all the things you gave me so far i taking it this is going into a truck and yeah i would for that particular subwoofer i would go with a sealed box and that would give you good performance and i agree with redskin that would be a much better box to build and sealed boxes have many good points to them. for a sealed box maybe something like 13"x22"x8" would work for you and depending on your truck or even car but the space you have to work with for the box you can make adjustments and play with the numbers for example 22" would be too wide then you can do 18" (22 inches minus 4 inches) and take those 4 inches you took off the 22 and add it to the 13 and that would give you 17" and then stillthe 8" and now we have 18"x17"x8" and maybe that size might work better for you or whatever you have to do to make the box fit but also always make sure you have enough room for the diameter of your subwoofer and also the mounting depth and a box thats too shallow wont sound as good so if you need to adjust any numbers try to go with more depth than reducing depth of the box. after you listen to your new box with sub then you can to some degree tune the box by adding poly stuffing from an old pillow or for a couple dollars at walmart for about 18 oz i think but you can add some if you need it if the box sounds too "boomy" and you want to tighten it up but then again you may like the boomy bass and some people like it too its a personal preferance. if the suggested dimensions are still too big then let me know how that might fit in your truck or car and i can think about it and actually go a bit smaller and come up with something that will fit better and with a sealed box you can cheat a little and use a smaller than recommended enclosure and use "stuffing" to create the characteristics of a larger box. if more than numbers are needed then i can email you somethiing drawn out like a blueprint if you needed. one other possibility since you are pretty fortunate and the upper limits of your sealed box can be pushed and you can go a little larger if you have the room and try a box thats 16"x26"x10" and use it as a sealed box at first and then later you can go to a ported box if you wanted to change your mind. since there is no universal type of box doing either would change the dynamic range but it would be so small that in this case i dont see any harm in trying it. jay |
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New member Username: SakuPost Number: 6 Registered: 12-2003 | oh wow thats some good infromation. so it looks im gonna go with the sealed box, but im the kinda guy who likes to know alot about all the things i do, i like to understand what im doing and not just do it for the sake of doing it. So it sounds like having the box im maling dosent have to be exacly precise, and what i mean by that is...... say for exampel i mess up cutting one of my box sides and im off by 1'', before i thought that would change the preformance of my sub dramatically, but its good to know it wont. but as i said i like to understand what im doing so how would i know the exact perfect box size for my particula sub? lets just say for example i had enough room in my truck for any size no matter how big or small...whch box size would be the best? or can i fill a huge box with stuffing to make it sound even better? oh yea and one last thing.... if its not too much trouble for u Jay, would it be possible for u to email me some blue prints of any size box but put some porting in it i kinda want to see what it looks like (iv never seen a ported box before, so i want to see exacly where the tube goes....i mean does it stick out down be the magnet...or where )just incase i ever want to make a ported box ill sort of know for the future. ok thanks colby oh yea i almost forgot my email is colbynye@shaw.ca |