box tuning?

hey you guys im making a box for 4 12's ported. They are memphis power reference subs and the spec sheet recommends 40 hertz.  I listen to deep rap and i want it to hit low and deep. Is 40 to high or should i go to like 35 or something. thanks

I doubt many will agree with me, but as a former user of ported boxes, I think that you get much better performance from sealed boxes. Ported boxes give you a much louder sound at certain frequencies, but it is only truly good at those certain frequencies. In fact, some rap songs don't even sound good with ported boxes. I think mine was tuned to around 35 hertz. If there were hard beats around that frequency, they were loud and clear, but ask for a noise anywhere outside that frequency range, and the sound is muted and in some cases in audible.

Sealed boxes give you great sound quality and bass response over a larger frequency range. Plus they're a heck of a lot easier to make...haha

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~WAYLAND

https://www.memphiscaraudio.com/LiveImages/112/56/DocumentURL1.pdf

...box specs under PR124 or PR124D, depending on if your subs are dual voice coil or not.  Just multiply X 4 and either give them each a port in their own chambers or use a vent calculator like this one to use one slotted or round port for all four.

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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.

my specs that came with the box said do it at 40 do u think doin it at 35 would be ok? adn would it be that much deeper?

Using 4 subs, you have space considerations.  If you look at the recommended ported box specs for that type of sub you'll see that 43 Hz is the tuning for the smaller (1.5 ft) size box and 38 Hz  for the bigger 2 ft size.  Now, with all those subs and their displacements, port displacements and bracing that will be involved...you got yourself a BIG box either way you look at it.  But if you intend to go with 4, you have to give up the space.  Use one of the two recommendations in that chart.

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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.

I dont know what kind of vehicle this is in but my sub box was just a hair under 9 cubic feet total for my 4 12's and I had to make two of those, one for my swift and one for my S-10 so it might not be about lack of room, just about lack of comprimise. As far as porting frequency, I tend to port my boxes real low, like my last one ended up being around 27-28 hz. Not the best for SPL comps but sounded way better to me and I needed my vehicles to be able to be both, comp and daily driver

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double-secret reverse-osmosis speaker-cone-induced high-level interference distortion, Its a killer

ok thanks stevdart. i do have enough room so im going to go with the bigger 2.0 foot cubic box. but now each box is gonna have a seperate slot vent port so should i build each chamber to the opt one sub box. or can i use the opt 2 box? and also how come its 2.0 cubit ft for the one but for the 2 sub specs it says to make it 3.5ft i dotn get it?

What Ravendarat is saying is good advice.  Manufacturers give a workup for what they believe the majority of that particular models' buyers might want.  This sub has an Fs of 32 or 33, so tuning low (down to 25) can be done.  However, the bass in most hip-hop/ rap is higher than that, and much closer to the 40 Hz area.  Use the calculator to figure tuning for a lower port tuning for possibly better all-round listening, but use the 40 Hz range for most response with what you are referring to as "deep rap".

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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.

what does the calculator help me with?i think im gonna use winisd because the ports are gonna have to be L ports and the box is gonan have to custom fit my dakota extended cab. Should i still port it at 38 hertz? and how much difference would 2 herts be like would it be noticeable?

yes! your best bet is using winISD, it will show you different frequency response for different box sizes and frequency cutoff points. look for the flattest curve on the graph, that way you get the most out of your subs.

wrathchild281 wrote:

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.. but now each box is gonna have a seperate slot vent port so should i build each chamber to the opt one sub box. or can i use the opt 2 box? and also how come its 2.0 cubit ft for the one but for the 2 sub specs it says to make it 3.5ft i dotn get it?

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My instincts tell me it came about something like this:

Memphis tech 1:  I have to come up with some box specs to put on the site so we don't get bombarded with emails on what size to use.  I think I'll figure out, like, two different sizes...you know, give them options.
Memphis tech 2:  Yeah, that's good.  Do, like, one a little bigger than the other and maybe change the tuning, too.
Tech 1:  The thing is, most of these guys have two subs now, so I'm afraid they'll still be calling because we're only listing specs for a single sub...so I think I'll do up another one with, like, double the volume for two...
Tech 2:  Yeah, that's a good idea.  But, can't they just double it themselves?  I mean, maybe we should throw out another option here...if they have 3 options that's less emails we get!  Maybe split the difference...
Tech 1:  Done deal.  We'll make it 3 1/2 for the double.  That'll work.

So with that bit of fantasy, I'm trying to prove that it doesn't make a whole lot of difference which you choose, and that there is no rhyme or reason to make the two-sub box slightly different than what you'd get if you just doubled the size yourself.  So much of a sub installation depends on quality of the build, integrity of the wiring, placement of the drivers, accoustics of the vehicle....etc...etc.

So you should just keep the things in mind that you've learned about placing subs, such as: 

• with multiple subs make sure they are firing in the same direction................
• all subs having the same impedance and phase...............
• all subs in identical air volumes...............
• all ports identical.......
• smaller enclosure if you have a lot of power to give them, larger enclosure if the power is meager.............stuff like that.

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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.

ok well im gonna have a jbl 1200.1 pushing the 4 subs so ya thats around 300 a sub and there rated at like 200 or 250rms. Do you recommend i go with the bigger or smaller? which is gonna be deeper and hit harder?

They're rated for 250, IIRC from looking at it earlier...so if you send them each a true 300 watts....they'll hit hard, alright!  Harder than you want them to, I suspect.  In a situation like that, where power exceeds the capability of the subs, I would seriously look at putting them in sealed enclosures.

Oh, and about that stuff above....you read the info a little wrong in that chart.  What they're doing is showing you options for box sizes with the vent dimensions figured for you, that's all.

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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.

ok thanks stevdart. so you think that 4 12's sealed is gonna be louder then 4 12s ported? Remember im lookin more for spl not sq.

No.  Safer.

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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.

ok is it still gonna be loud? and how much difference would it be between the two boxes

Subs in ported boxes need less power than subs in sealed boxes...

That's a given.


As for loudness, I'm sure they'll be pretty equal, as long as you have set up the amplifiers properly, and have enough RMS power from the amplifier to power the RMS rating of the woofers.


All subwoofers are rated at a Maximum RMS power rating, meaning, that is the most RMS power a woofer can handle. However, this isn't the way to judge how much power your subwoofer will need. These ratings are usually for sealed enclosures of a certain size.   However, take the same woofer and put it into a ported enclosure, and you'll find the woofer will need far less power than what it was rated for. In fact, placing a woofer into a ported box, while trying to give it the RMS rated power will probably destroy the woofer.

So, if you read all that, what I'm trying to say is as soon as you set up your amplifiers properly, they should be equally loud. It's just that ported enclosures are more efficient.



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~WAYLAND

ok ya i think im gonna port them and just set the gains and everything and i should be alrite, thanks for the info and how many hertz would you guys port it at? give me some numbers

anyone?