BMS Posted March 20, 2016 Report Posted March 20, 2016 not a single calculator on the internet seems to give me the same answer. fs 33hz, qts .2, vas 57.5L what is my optimum enclosure volume? it is ported (single square port) 2 subwoofers with those same parameters. 15'' cone diameter each sub. common chamber (same air space). sub displacement isn't specified but they are neodymium so smaller than one may expect.
Triticum Agricolam Posted March 20, 2016 Report Posted March 20, 2016 What subs are those? A QTS of .2 is super low. There isn't one "optimal" enclosure volume. It depends on what you want to do. What's optimal to one person might be flattest response. Another person may want max output. They are going to need different box specs. "Nothing prevents people from knowing the truth more than the belief they already know it.""Making bass is easy, making music is the hard part."Builds:
BMS Posted March 20, 2016 Author Report Posted March 20, 2016 I like high output on the lows and to feel the bass but i have a problem with face area making my port area a little small if i want 15's, 72 in squared port area. the subs are pride ufo.3 15 http://pridecaraudio.com/download/pdf/ufo3-15.pdf
Triticum Agricolam Posted March 20, 2016 Report Posted March 20, 2016 What amp are you using? "Nothing prevents people from knowing the truth more than the belief they already know it.""Making bass is easy, making music is the hard part."Builds:
Triticum Agricolam Posted March 20, 2016 Report Posted March 20, 2016 Those subs have interesting specs. They have really tight suspensions and really powerful motors. Clearly they are geared towards max SPL and as such are going to be very peaky in any reasonably sized enclosure. They have tons of Xmax so you shouldn't have to worry about excursion, even in a large enclosure. What vehicle do you have and how much space do you have available? Just from looking at the T/S specs those subs are going to be peaky no matter what you do. I'd just put them in a reasonably sized enclosure for a pair of 15s, so 6-10 cubes net volume, tune to what frequencies you want to get the loudest. With the amount of power you are going to be running you are going to want lots of port area. 150 sq in would be my recommendation. If you aren't able to fit that you may want to explore other options. "Nothing prevents people from knowing the truth more than the belief they already know it.""Making bass is easy, making music is the hard part."Builds:
BMS Posted March 21, 2016 Author Report Posted March 21, 2016 thank you for the info i have plenty of space 16 cubes (estimated it is not a totally square space) pontiac grand am. I do't really know that i like them to be peaky id rather have a flatter response but i have limited face space on the box so i would need to move down to 12's to get 150 in2 of port area that or i suppose the port doesn't have to be square right. fairly sure ive decided on a tuning frequency of 32 hz.
Triticum Agricolam Posted March 21, 2016 Report Posted March 21, 2016 Your port doesn't have to be square. Just about any way you can fit the port in should work. I've seen designs were the port is in an hourglass like shape between the subs to get the maximum amount of area in. "Nothing prevents people from knowing the truth more than the belief they already know it.""Making bass is easy, making music is the hard part."Builds:
BMS Posted March 21, 2016 Author Report Posted March 21, 2016 ok thanks a lot i think i have everything i need except i don't know what i want my enclosures volume (net) to be. what changes when you increase/decrease the enclosure volume assuming the port volume changes with the enclosure volume to keep the same tuning. I have heard a bigger enclosure volume makes the subs response less flat. i can get 125 in2 of port area the drivers response is more accurate with less port area but output is lower?
Triticum Agricolam Posted March 21, 2016 Report Posted March 21, 2016 You are correct about enclosure volume, the larger it is the more output you get around tuning and thus the less flat (more peaky) the output becomes. With port area, the goal is to have enough port area so that port velocity doesn't become so high it negatively affects output, which is called port compression. You can also get port noise from the high port velocity. Just how much you need depends on the size of the box, the tuning frequency, how much power you are running, etc. The 150 sq in I recommended was based on a box with 8 cu ft of net volume, 33 Hz tuning, and 7k of input power. If you increase the net volume, raise the tuning frequency, or increase input power you will need more port area, conversely if you decreased net volume, lowered the tuning frequency, or used less power you would need less. With just about every car audio installation, space is tight, so compromises often need to be made. If you are limited by the amount of panel space you have to fit the subs and port you just do the best you can. If you can get 125 sq in, it won't ideal, but it won't be terrible either, you just may lose a little output or have some port noise at max volume. "Nothing prevents people from knowing the truth more than the belief they already know it.""Making bass is easy, making music is the hard part."Builds:
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