Mounting Sub Box to Rear Deck and Using Rear Deck Speaker Holes as Ports

[Jimily412]

I have a 2011 Nissan Altima 2.5 S. The car comes stock with 8 speakers total. I have also added two subs and all speakers in the car are now aftermarket. I've been thinking that between the 4 speakers in the doors alone I have plenty of mids, so it shouldn't be an issue to do away with the deck speakers. My subs also aren't competition or anything close. Quite budget actually. I just remember the guy at the audio store was once talking about getting rid of the rear deck speakers and using the holes as ports for subs. I'm wondering how possible/good of an idea this is. My hopes are to get the absolute most and best out of my system, but I do understand the limits of a budget. I am also thinking of upgrading to two identical subs rather than what I have now. There were some nice Alpine type R 12's in the fancy box that I'd like to get, but would obviously just opt for the speakers without the box if they'd be going in this enclosure anyways. So another question is how would it perform as I upgrade the system as well. If this idea would even be plausible could someone possibly provide me some math to making the box as "acoustically perfect" as it can be.

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[SlugButter]

For a ported setup you’d want to build the box so the sub and the ports are in the rear deck, not just the ports. If you’re doing a 4th order or 6th order bandpass, then it would only be ports in the rear deck.

 

[Jimily412]

For a ported setup you’d want to build the box so the sub and the ports are in the rear deck, not just the ports. If you’re doing a 4th order or 6th order bandpass, then it would only be ports in the rear deck.

Okay so let's talk about 4th and 6th order. That's a new concept for me. But I just did a quick google and I like the idea of that more anyways because It would provide better protection for my subs as well. Although, one could argue that I'd have to have a box so big that I wouldn't be able to put anything in my trunk to damage the subs in the first place. But that aside. I like the idea and it would be a bit of a challenge. Is there any specific math to this?

 

[SlugButter]

Okay so let's talk about 4th and 6th order. That's a new concept for me. But I just did a quick google and I like the idea of that more anyways because It would provide better protection for my subs as well. Although, one could argue that I'd have to have a box so big that I wouldn't be able to put anything in my trunk to damage the subs in the first place. But that aside. I like the idea and it would be a bit of a challenge. Is there any specific math to this?

There is a ton of math, and getting it wrong will have bad results, especially with the 6th orders. 6th orders are above my level still. I could build one from a blue print, but designing a nice musical 6th order in software is something I haven’t designed and built. I’ve played with it and can get some decently flat response curves in box programs, but never built one in real life yet.

 

[djdilliodon!]

Getting rid of rear speakers isn’t a bad thing, actually it’s beneficial. Unless you are gonna be watching movies in your car, when playing music the rear is useless if sound quality is the goal. Of course this also comes down to personal preference as well. A band pass box isn’t for everyone and I’d highly recommend you demo a view before going this route. They are also not simple to build properly either with many of the prefab ones being one note wonders with laughable sound quality (to me at least). What is the goal with your setup? Do you want it to just get loud, want all out sound quality, or a mix of both? If known, what frequency range in the bass notes do you like the most?

 

[Jimily412]

Getting rid of rear speakers isn’t a bad thing, actually it’s beneficial. Unless you are gonna be watching movies in your car, when playing music the rear is useless if sound quality is the goal. Of course this also comes down to personal preference as well. A band pass box isn’t for everyone and I’d highly recommend you demo a view before going this route. They are also not simple to build properly either with many of the prefab ones being one note wonders with laughable sound quality (to me at least). What is the goal with your setup? Do you want it to just get loud, want all out sound quality, or a mix of both? If known, what frequency range in the bass notes do you like the most?

A mix of both would be preferred. However I am much more willing to sacrifice loudness for quality than I am to sacrifice quality for loudness. My ultimate objective is to have every frequency get hit with good quality. I don't know anything specific as for what ranges I want the subs to hit but I have my LPF at 80. I am generally satisfied with my subs right now minus the fact that the quality is really killer in some freq's but absolutely horrid in others. And also the fact that with all other speakers in the car being decent quality aftermarket speakers I find myself maxing out the subs far before the interior speakers reach their threshold. Another purpose for wanting to at least have the box mounted to the deck is that I get tired of always having to readjust my boxes in my trunk because they slide around.

 

[Jimily412]

Getting rid of rear speakers isn’t a bad thing, actually it’s beneficial. Unless you are gonna be watching movies in your car, when playing music the rear is useless if sound quality is the goal. Of course this also comes down to personal preference as well. A band pass box isn’t for everyone and I’d highly recommend you demo a view before going this route. They are also not simple to build properly either with many of the prefab ones being one note wonders with laughable sound quality (to me at least). What is the goal with your setup? Do you want it to just get loud, want all out sound quality, or a mix of both? If known, what frequency range in the bass notes do you like the most?

I feel it may also be worth noting that my music choice generally shifts from hip hop to metal the most. Other than that I listen to rock and a very little bit of country and pop. Emphasis on very little. If that helps with freq ranges. I suppose I'd be most satisfied if I could just get all the bass notes to get hit. My system handles the middle range of the bass notes but gets quieter at the lower notes and really sloppy at the high ones.

 

[djdilliodon!]

A mix of both would be preferred. However I am much more willing to sacrifice loudness for quality than I am to sacrifice quality for loudness. My ultimate objective is to have every frequency get hit with good quality. I don't know anything specific as for what ranges I want the subs to hit but I have my LPF at 80. I am generally satisfied with my subs right now minus the fact that the quality is really killer in some freq's but absolutely horrid in others. And also the fact that with all other speakers in the car being decent quality aftermarket speakers I find myself maxing out the subs far before the interior speakers reach their threshold. Another purpose for wanting to at least have the box mounted to the deck is that I get tired of always having to readjust my boxes in my trunk because they slide around.

I didn’t see you list what subs you have and how much power you are running or what box type they are in. What’s the details on the current setup? Post that along with with amp specs and we can go from their, the options are truly endless but it’s not hard to put you on a path. Also post what you are willing to spend .

 

[Jimily412]

I didn’t see you list what subs you have and how much power you are running or what box type they are in. What’s the details on the current setup? Post that along with with amp specs and we can go from their, the options are truly endless but it’s not hard to put you on a path. Also post what you are willing bro spend .

Well I am not sure the power and I dont have boxes any more but im running an alpine s 10" and a JVC GigaTube with only the sub plugged in or something like that. Along with an alpine amp. All the alpine stuff is less than 2 years old. But my ultimate objective is to have 2 alpine r 12"s. Also none of my interior speakers are powered. So i have been tinkering with the thought of maybe getting a 4 channel amp and upgrading my door speakers again, but that again bears the question of my subs being able to get as loud as them. And I understand that quality costs money, which is my goal, but I am still operating on limited funds. Anything I buy I will likely have to save for no matter the cost. So I'll pay whatever really as long as the quality definitely makes up for it. Like I said, dont know the power, but IF I HAD to guess I'd say the amp is 600 rms monoblock. EDIT: Added photos of everything mentioned here. The amp in the picture is the amp I am running.

 

[SlugButter]

Well I am not sure the power and I dont have boxes any more but im running an alpine s 10" and a JVC GigaTube with only the sub plugged in or something like that. Along with an alpine amp. All the alpine stuff is less than 2 years old. But my ultimate objective is to have 2 alpine r 12"s. Also none of my interior speakers are powered. So i have been tinkering with the thought of maybe getting a 4 channel amp and upgrading my door speakers again, but that again bears the question of my subs being able to get as loud as them. And I understand that quality costs money, which is my goal, but I am still operating on limited funds. Anything I buy I will likely have to save for no matter the cost. So I'll pay whatever really as long as the quality definitely makes up for it. Like I said, dont know the power, but IF I HAD to guess I'd say the amp is 600 rms monoblock. EDIT: Added photos of everything mentioned here. The amp in the picture is the amp I am running.

What kind of funds are you working with? I don’t think you should try to build 4th order or 6th order boxes yourself, and they are going to cost a bit money to have them done right. If you’re doing this build yourself, I would for sure stick to sealed or ported to start out with. My opinion.

 

[SlugButter]

Or infinite baffle, but I’m not sure about using type Rs for that. The older ones worked I think. Not sure on the new ones

 

[Ridinhi 5,000+ posts]

I didn’t see you list what subs you have and how much power you are running or what box type they are in. What’s the details on the current setup? Post that along with with amp specs and we can go from their, the options are truly endless but it’s not hard to put you on a path. Also post what you are willing to spend .

Wow, back from the dead!! Hey man. I remember you dealing with cdt back in the day. I see you have got a new business with a sub that I would like to try. Do I need it, no. Am I addicted, well, depends who you ask!!
Good to see you are back.

 

[SlugButter]

What is a gigatube?

 

[Jimily412]

What kind of funds are you working with? I don’t think you should try to build 4th order or 6th order boxes yourself, and they are going to cost a bit money to have them done right. If you’re doing this build yourself, I would for sure stick to sealed or ported to start out with. My opinion.

Yes I am beginning to see the issue with trying fancy boxes. Does anyone happen to know any good websites that I can buy a box made custom for my car? Mainly to avoid having to readjust it all the time and to make it more space efficient in my trunk. Or would it even still be an idea to cut bigger holes in the deck and mount my subs and box to the deck and cut one big port in between the two subs on the deck? Which of the options would sound better, cost aside? I've heard putting subs in the cab of the vehicle can cause it to be really choppy because only some of the bass wave has been produced by the time it hits you. The guy at the audio store even advised pointing the subs toward the rear of the vehicle in the trunk for this reason. Another question I have is about making the bass less resonant with the car. As my speed increases the quality and loudness of the bass greatly subsides. Any fixes for this?

 

[SlugButter]

Yes I am beginning to see the issue with trying fancy boxes. Does anyone happen to know any good websites that I can buy a box made custom for my car? Mainly to avoid having to readjust it all the time and to make it more space efficient in my trunk. Or would it even still be an idea to cut bigger holes in the deck and mount my subs and box to the deck and cut one big port in between the two subs on the deck? Which of the options would sound better, cost aside? I've heard putting subs in the cab of the vehicle can cause it to be really choppy because only some of the bass wave has been produced by the time it hits you. The guy at the audio store even advised pointing the subs toward the rear of the vehicle in the trunk for this reason. Another question I have is about making the bass less resonant with the car. As my speed increases the quality and loudness of the bass greatly subsides. Any fixes for this?

Dang. You’re from north platte? I grew up around mccook just south of you.