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Ok, I've been driving around with three subs in a custom box (made by me) and I honestly believe it's too much weight and too much bass for me. (I never thought I would EVER be saying that, but I guess I have already grown out of it). I am selling two of my subs and only keeping one. Question is....what type and size box would you recommend for one RF Punch HX2. I'm going to be pushing it with a Bazooka EL1500 (I don't really like bazooka, but for $45, how can you go wrong?). I want to go for a mix of SQ and SPL (probably more toward SQ). As for the rest of the system, I plan on pushing the 6X9s and 6.5s with a Kenwood amp (30-35wx4, not exactly sure on the specs). Would you recommend getting a new head unit with three sets of pre-outs or should I run speaker wires back and forth through the car? All your help is appreciated. Thanks a lot. Oh, and also, if I wanted to run wiring down the middle of the car, how hard would it be?

 
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Hey whats up. Here's the deal. For that sub you can have a ported box at 2 cubic ft. This will be more efficient with the power you have and hit harder than sealed but for Sq you would want to go sealed in a 1.25 box. whats the power on that amp?? i just did a sealed box with 4 of those and they hit pretty hard but Rockford really isn't known for great SQ. Now are you running a stock deck? or just a Deck with one rca output? If you have the extra money i would say upgrade to a new deck like Premier DEH-P740MP you can get it for under 300 at www.Smilephotovideo.com. this will give you 3 sets of outputs so you can control your sub from you HU with crossover settings and a +,-6 boost. And all sets of outputs are a clean 4 volts. Now for you mids i would say either sell that amp and your 6x9's and get a good 100x2 amp and some nice components for the front ( Infinty Kappa 6.5's are the components of choice on this site for value and SQ) or you could brige the amp and run it for 2 chanels for your fronts. With that much pwer you really don't need rear spkrs it will sound fine. then just pull out your center console and pull out the bottom back seat. You can run your wires right down the middle there and then sneak them under the carpet with-out having to unbolt your seats. But its easier with the pass. seat out to lift the carpet. but it can be done [IMG]i/expressions/face-icon-small-smile.gif[/IMG] good luck and i'm sure Mowhawk will give you close to or the same advice. And if white Rabbit replies. Oh lil bunny i'm sure you'll put a loop into this whole ordeal.........

 
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^^^^^^^^^^^^^^^^^^^^^ummm..what he said!^^^^^^^^^^^^^^^^

But that sub is a Punch..or Power HX2?..

 
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<< And if white Rabbit replies. Oh lil bunny i'm sure you'll put a loop into this whole ordeal......... >>



well how can i refuse an invitation like that? just cause of that, i even pulled off the t/s ofa RF site just to double check all the frequency responses....... [IMG]i/expressions/face-icon-small-smile.gif[/IMG]

alright, im gonna make an assumption that you have the punch HX2 12' 4 ohm DVC sub. if im wrong, correct me and disregard everything im gonna have to say about your box. (rated @ 500 watts RMS)

alright, assuming you have an RFD2212, modeling it up tells me that that for SQ purposes, a .707 alignment (where the vacuum pull by the box does not affect SQ) is a sealed box of 2.25 cubic feet. This is to be expected, as many sub companies push thier subs to be in overly small boxes in order to create overly tight bass (JL is the perfect example. even their "purist" boxes have a Q of .8, which 95% of audiophiles would not touch with a ten foot pole.)

now, if you are gonna go sealed, I present you with a new option: isobaric. you have the woofers already, and power comes cheap. two 12's in an isobaric install in 1.2 cubes would sound IDENTICAL in every respect to one 12 in 2.25 cubes (you have to double the power, instead of 200 watts to one 12, now its 400 to 2 12's, or 200 each) this will cost more money in the end, but in terms of weight and space saving, you will come out ahead.

.707 aligned RF willhave a FLAT reponse down to about 80 Hz, and roll off gently after that, porducing an F3 (the frequency that plays 3dB below zero gain) of 38 Hz. my box itself has an f3 of 25 Hzish, i get it loud there, and i still get a response at 20. therefore, with this box, (either one in 2.25 or two isobaric in 1.2) I will venture a gues that you will be able to play down to around 30 or 29Hzish or so before losing response.

now let us consider ported boxes. flattest response happens in a 4.7 cubic foot box (also expected) tuned to 22 Hz (although its generally not a good idea to tune below Fs) this box will give you a DEAD FLAT response down to just below 30 Hz, and a sharp decrease in response after that. F3 is 19.6Hz!

you will pay teh price in weight and space, as even isobaric loading makes the box only 2.3 cubes in size. still pretty damn big [IMG]i/expressions/face-icon-small-sad.gif[/IMG]

now, I will investigate factory reccommendations: I predict that sealed will have a Q of 1.1, and a HUGE peak at 70, with an F3 of 50, while ported will go slightly lower, but still a nasty peak at 50.

sealed: Q of .85. not too bad. peak of .4 db above zero at 90 Hz, way above the crossover point. F3 is 40 Hz. other than your loss of SQ cause of the Q being so high (the air pressure in the box will be much greater than what the sub wants to do with the signal) the frequency response difference is negligible.

ported: tuned to 27, to make sure its low, yet above Fs. nasty 1.65 db peak at 50 Hz, as predicted (boy was i off about the sealed box!) F3 is 27 Hz.



so what have we learned? the BEST way to save weight and space would be keeping both subs and running them in an isobaric configuration. out of all those boxes above, (you wanted an SQ SPL mix) I would have to say that without a doubt, the factory reccommended 2 cubes ported is the way to go. With an isobaric setup, you not only have alot of room for creativity, but you also only require a 1 cubic foot box (1.1, 1.2, around there) after port and driver displacement. experimenting with port frequencies, I have come to the conclusion that 27 is the ideal port tuning, as it gives both the lowest peak and the lowest F3.

your system would sound about as goot as its going to, and you would only notice the peak when playing sweeps (techno, basically)

give me a second, I'll discuss the rest of yoru system in the next post.

edit: forgot to say, ben and mowhawk are dead on this time, and ^^^ thats why [IMG]i/expressions/face-icon-small-smile.gif[/IMG]

 
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now for teh rest of your system.....

certain things must be taken care of before removing teh rearfill and having it sound good. you need to have enough midbass up front to take teh response down to teh sub, otherwise youll have a huge hole in response. not good.

I do not know what speakers you have, but unless they are pretty high quality (infinity without doubt makes the cheapest that can do so) you will want to keep your 6x9's.

to set up rearfill properly, you want almost no sound coming from them. this aids in keeping a system cheap, because you cna run them on deck power. cross tehm over so they do not play sub frequencies, or midrange frequencies (80-400 Hz is a good starting point) and run them on deck power, maybe even will need an L-pad anyways to get them to play softer. this takes care of what kind of speakers you will need and what amps.

as to teh deck, you have several choices. if you INSIST on seperate control of the sub vs the rear speakers, then you have a couple options. you can get an amp that has a remote bas control gain (RF or kicker, there are a billion amps out there) or you can get a deck with three outputs, and control it from the deck. most of us tune using the gains and leave it, so were ok with it. OR, if you ditch teh rearfill and go for speakers up front with good midbass capabilities, then you dont need three outputs to begin with. front + rear(sub). gives you all teh control you want.

decks nowadays put out about 20 wattsish RMS for deck outs. this can be fine, depending on what speakers you run. infinity reference, for example, sounds great off deck power, and can even take 100 watts, tho theyll get a bit bright. kappas will probably want a bit more, and still be pretty bright at 100 watts, but will sound very nice. if you have pioneer coaxials, best to keep them on deck power permanently [IMG]i/expressions/face-icon-small-wink.gif[/IMG]

I hope I was able to clear up anything or maybe confuse what mowhawk and ben already answered [IMG]i/expressions/face-icon-small-wink.gif[/IMG] i think i covered everything, but if i forgot anything, lemme know (let us know ;p) [IMG]i/expressions/face-icon-small-cool.gif[/IMG]