40hz for 2512?

[SMS 10+ year member]

according to my calculations dd suggests a 2.5ft3 box tuned to 40hz-they call for 40 sqin port area 21" long. In a box that i would build that would be a 13.5"x2.875" slot.

Any box designers suggest this for an optimuim enclosure for a daily sub in the trunk of a maxima?

Its in a older box i built for another sub-2.3ft3 tuned to 34hz, it sounds pretty good and gets loud but ive never heard it in any other box. Just looking for anyone that has exp with this sub and what worked best for you.

its running off a M1 so it s got plenty of power.

thanks for any help

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[disturbed471985 5,000+ posts]

Im no exp but my 2510 loved 1.9cf tuned to 37.5hz with 36sq" of port

 

[Moble Enclosurs 10+ year member]

For the 2512, the basic calculations I can gather without looking too far into them is this:

volume: 3.79 cubic ft

port area:81.2 square inches

tuning: 36.26Hz

voltage: for d4 paralel-32.56V d4 series-65.13V d2 parallel-23.03V and d2 series-46.05V

*Port length will be determined by further calculation accuracy. I have the parameters of port dimensions, but this is what I will show.

 

[Bettr n' Revrse 5,000+ posts]

I wont ever tune close to that high for daily... My 2512 was in 2.25 tuned at 38 and after having my skar at 31 I won't tune much higher then that from now on lol...

 

[Flastrongman 10+ year member]

2.5 is pretty optimal for these subs. I like 35-37 for daily tuning with them.

 

[Moble Enclosurs 10+ year member]

By having it tuned around 30Hz, you create an out of phase response from around 33hz-70Hz, but this can be adjusted by putting the port on the side and sub to the back or on the top. So, I will not argue that a lower tuning will still work with this driver, but I want to show you something.



This first image is the phase of the 3.79@38Hz. Everything is explained in the pictures. This is to compare my recommendation with the others.



The second one is the phase of my 3.79@32Hz--your lower tuning preference.



This third one, is your 2.5@31-32Hz. Notice the out of phase band. This will effect low end but you will not notice it due to tuning. In this example, tuning is a "fix" for lost output. Not something I want to deal with when designing. I do not hide output loss. I correct it.



The one above shows the responses of my 3.79@38Hz, and your 2.5@32Hz. You do get output increase below 35Hz with your tuning, but this will change with acoustical loss from phase output, and also my response is an average of 2-3dB higher in the rest of the response.



This last one adds my 3.79@32Hz to show the output comparison to your 2.5@32Hz.

Also, the Group Delay is decreased by 14% by going from 2.5@32Hz to 3.79@38Hz. It goes from 70 msec peak to below a 60msec peak. Also, it gets rid of the peak just above 120Hz.

This is just to show the given against my recommended. Not to start any preference wars. I just need to show you that there is a reason for my recommendations, and I do not disagree with any other of your guys' recommendations either. If they work for you, they work. That is perfectly ok. //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

 

[Moble Enclosurs 10+ year member]

This being said, the best thing to do if you were to combine the ideas of both my recommendations and others lower tuning, you can use a 3.79cft@32Hz. This would balance both out pretty well and give you a more accurate response. Just trying to help.

 

[SMS 10+ year member]

Thanks guys, im a little confused how you came up with 3.79ft3-that is massive for a single 12"-1.29 larger than DD recomends.

Using thereT/S parameters you got 3.79 as the best box size, or is that from exp with the sub?

I cannot accomedate(nor spell) that size of a box, 2.6ft3 after all deduction using a 4" aero port is going to be the best I can do for now.

Thanks again for the help

 

[Moble Enclosurs 10+ year member]

Because I design for efficiency. You are not supposed to know how I did it, either,lol. I do not use manufacturer specs, nor did I take into account any of your limitations yet.Some manufacturer specs for box volumes and ports have been close enough to be considered accurate in a few cases I have found, but most are not when dealing with box parameters. Within your limitations, obviously you cannot use what I recommend, therefore you have a "limitation". It is normal. So, what we normally do in this case, which is very common, is design around your limitations. This is where dimensions come into play. But after all of this, I would require a purchase in order to help you any further.

Or, trust a free one. You seen my evidence of how mine can differ. A lot of people do not worry about a lot of the parameters that I calculate for, or they rely on a program to do it for them. The program may only be as accurate as the user, not to mention.....how do you know the program takes into account different variables that are needed?

Anyway, I have done what I could do without getting involved to the point of having to customize the design goal for you, in which, again...because I run a business, this would require a design request.

Other than that, I hope you get what you are looking for and that it works out for you. Ill always be here if you want to further investigate the design possibilities more accurately.