From Ported, to port sealed over, to re-porting... My box is evolving!

[DBz Hertz 10+ year member]

Ok.. first off, this may confuse some of you.

I need to know if what I'm trying to do is possible, or even recommended. The best way to explain? MS Paint.. Here goes.

Here is my original enclosure, built for 2 IDQv3's. It is approximately 5.35 cu. ft. and it's port tuned to some higher frequency around 42 hz or so. It was built by a builder here in De. I wanted to focus on SQ, so he tuned it high. Well, I don't like it. First of all, I blew one woofer. Rookie mistake. Also, for me, sealed just does a better job of SQ, so I had him seal the port, and put a new top piece on for 1 15" instead of 2 12".

So, here we have the current enclosure. It has been sealed off, and now accommodates a single 15" woofer. I've decided to go with a single 10 in a custom enclosure for my SQ, but now I wan't this 15" to be LOUD and LOW.

I will have 2 separate systems incorporated in my vehicle. One single 10" for SQ, and 1 15" for SPL, controlled each by their own switches on the dash. So, I want to port this thing again, but I also want to decrease the internal volume.

My plan is to do this....

I want to put in place structural triangle braces, blocks of wood cut at a 45 degree angle. This should lower the box volume to my specifications. Also, I want to install a series of tube ports to create a new tuning frequency around 32hz.

Is this feasible? From what I've read, these structural braces are fine, but my main worry is the port within a port. Is this going to cause any issues? Can I consider the old port wall a structural brace? I'm wanting an SMD 15" or a AA Mayhem 15", and my reasoning is that this old port wall can serve as extra bracing..

Thank you for your help.

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[THATpurpleKUSH 5,000+ posts]

First off you don't tune high for sq, you tune high for spl. Find a new box builder.

Just have a new box built to begin with and stop trying to cut corners modifying your old one.

 

[DBz Hertz 10+ year member]

First off you don't tune high for sq, you tune high for spl. Find a new box builder.
Just have a new box built to begin with and stop trying to cut corners modifying your old one.

Ok, I agree with you about the box builder. I KNEW tuning for low freq = SQ, I guess I just figured he knew what he was doing and let him take the reigns. I kick myself for letting that happen.

Stupid mistake.

But, I have to disagree with you on cutting corners. Am I trying to save money by modifying my box? Yes. Does that mean the practices I'm suggesting are equivalent to cutting corners?

No. According to JL's website, corner structural supports are sound building techniques. They are a legitimate way to add structural support to your enclosure as well as displace air. I trust JL's support website.

As far as leaving the existing port behind, I can see how that could equate more toward cutting corners, but if it does nothing to affect the sound or tuning of the box, other than physically displacing air, where's the harm? How can that be a bad thing?

I am trying to save money, and from my research, the methods I'm suggesting have legitimacy. I'm not trying to be cheap and make a ****** box. In my mind, it is possible to salvage this box in a way that will not affect sound quality or frequency response in the end.

Please don't talk to me like a child that is ******* up. I'm trying to do this logically and with proven methods. I'm not trying to do a half-assed job. I don't have loads of cash to throw around, so I need to make this work if at all possible.

 

[JoshC 10+ year member]

You have alot of confused ideas, first of as said SQ tunning is 28-35Hz idk where ure getting this 42 crap. The size of the woofer has nothing to do with how it will sound and sealed DOES NOT sound better sq wise then ported for most subs. Now u can find subs that want to be sealed and will sound good but typically porting your sub will be more enjoyable in the end.

Ide do a single 15, in a completely new box designed by ram_designs, pro-rabbit, or mobile enclosures

Modifying old boxes is like jimi rigging it, just build a new one dude.... If u do it yourself its really not that much and designers can make u idiot proof plans

 

[JoshC 10+ year member]

Ok, I agree with you about the box builder. I KNEW tuning for low freq = SQ, I guess I just figured he knew what he was doing and let him take the reigns. I kick myself for letting that happen.
Stupid mistake.

But, I have to disagree with you on cutting corners. Am I trying to save money by modifying my box? Yes. Does that mean the practices I'm suggesting are equivalent to cutting corners?

No. According to JL's website, corner structural supports are sound building techniques. They are a legitimate way to add structural support to your enclosure as well as displace air. I trust JL's support website.

As far as leaving the existing port behind, I can see how that could equate more toward cutting corners, but if it does nothing to affect the sound or tuning of the box, other than physically displacing air, where's the harm? How can that be a bad thing?

I am trying to save money, and from my research, the methods I'm suggesting have legitimacy. I'm not trying to be cheap and make a ****** box. In my mind, it is possible to salvage this box in a way that will not affect sound quality or frequency response in the end.

Please don't talk to me like a child that is ******* up. I'm trying to do this logically and with proven methods. I'm not trying to do a half-assed job. I don't have loads of cash to throw around, so I need to make this work if at all possible.

So you ask a question and when you dont like out response you say IN MY MIND ITS STILL POSSIBLE. Then why ask us at all? Just hoping someone wants to go Frankenstein with you?

 

[THATpurpleKUSH 5,000+ posts]

If you want to save $, build it yourself and learn how to do it right in the first place. You will save a lot of time and effort by rebuilding rather than modifying. Most places where you buy wood from will cut it for you so all you have to do it glue and/or screw it together and cut out a hole. Anyone who absorbed even a trace of high school shop class can build a box. The 45s in the corners are fine but trying to put a port within an old port will not yield good performance. Yes it will work but it will not perform well.

And exactly how was I talking to you like a child? All I mentioned was "cutting corners" and you got butthurt and copped an attitude.

 

[DBz Hertz 10+ year member]

You have alot of confused ideas, first of as said SQ tunning is 28-35Hz idk where ure getting this 42 crap. The size of the woofer has nothing to do with how it will sound and sealed DOES NOT sound better sq wise then ported for most subs. Now u can find subs that want to be sealed and will sound good but typically porting your sub will be more enjoyable in the end.
Ide do a single 15, in a completely new box designed by ram_designs, pro-rabbit, or mobile enclosures

Modifying old boxes is like jimi rigging it, just build a new one dude.... If u do it yourself its really not that much and designers can make u idiot proof plans

As I stated in my first response, I trusted a builder who obviously didn't know what he was talking about. I thought that since he owned his own car audio shop that he knew what he was doing. My mistake, stupid mistake.

I know that lower tuning equals SQ. I knew it before, but thought I was wrong based on something someone else, who I thought knew what they were doing, said.

I never said that sealed = SQ, ported = SPL. I never said that sealed had better SQ than Ported. I said FOR ME, sealed produces better SQ in my limited experience with ported enclosures. I have never owned a ported enclosure that has the same punch as sealed, the same accuracy as sealed, and wasn't boomy in some way.

Whether or not I use the box I have is a moot point now. Now, I want to know why the methods mentioned above would be disadvantageous. I want proof as to why it's disadvantageous because according to JL's support site, at least one of the methods hold some weight and some value in the realm of box building.

I just need help understanding why it's a bad idea instead of someone just telling me,"It's jury rigged, do something else." Tell me why.

Thanks.

 

[DBz Hertz 10+ year member]

So you ask a question and when you dont like out response you say IN MY MIND ITS STILL POSSIBLE. Then why ask us at all? Just hoping someone wants to go Frankenstein with you?

Do I like the response? No. Why? Because it didn't answer any of my questions. All it said was "Don't do it this way." No detailed info was given as to why this would be a detriment to a box. According to what I've read from JL, these are proven, usable methods.

I get that the first responder didn't agree with the method I suggested, I was just looking for a reason why other than "It's ghetto rigged."

There's nothing "Frankenstein" about this as long as the methods are proven, and according to legit websites (i.e. JL), corner supports are a good way to add physical support and to lower box volume.

 

[DBz Hertz 10+ year member]

If you want to save $, build it yourself and learn how to do it right in the first place. You will save a lot of time and effort by rebuilding rather than modifying. Most places where you buy wood from will cut it for you so all you have to do it glue and/or screw it together and cut out a hole. Anyone who absorbed even a trace of high school shop class can build a box. The 45s in the corners are fine but trying to put a port within an old port will not yield good performance. Yes it will work but it will not perform well.
And exactly how was I talking to you like a child? All I mentioned was "cutting corners" and you got butthurt and copped an attitude.

I am not at all butt hurt. It just seemed like I was being talked down to for even mentioning the methods I did. Instead of suggesting that I do something else, I kinda felt slapped down, like I had blasphemed the box gods. Perhaps I over exaggerated your intentions. Sorry. I'm fine.

Thank you for helping me get closer to understanding why not to do this. You say, "will not yield good performance." I need to hear that, and I need to understand why. That's it. I'll gladly scrap this idea if it hinders performance in ANY WAY. I'm not stupid, and I don't want to put any money into something that isn't feasible. You've told me that it isn't realistic, so I won't do it.

 

[MisterDeadeye 10+ year member]

I am not at all butt hurt. It just seemed like I was being talked down to for even mentioning the methods I did. Instead of suggesting that I do something else, I kinda felt slapped down, like I had blasphemed the box gods. Perhaps I over exaggerated your intentions. Sorry. I'm fine.
Thank you for helping me get closer to understanding why not to do this. You say, "will not yield good performance." I need to hear that, and I need to understand why. That's it. I'll gladly scrap this idea if it hinders performance in ANY WAY. I'm not stupid, and I don't want to put any money into something that isn't feasible. You've told me that it isn't realistic, so I won't do it.

The old port is the only issue here. If you tear it out, you'll be fine, and I'm sure we can find something that would work for your box. We need to know what the net internal volume of your box would be with the port out, though.

 

[DBz Hertz 10+ year member]

The old port is the only issue here. If you tear it out, you'll be fine, and I'm sure we can find something that would work for your box. We need to know what the net internal volume of your box would be with the port out, though.

Great. I was thinking the port might be an issue, but I just didn't know. I'll have to see if I can remove the port. As far as the NET volume, that would be accounting for the woofer displacement?

I will measure the port and then subtract its area from the total. The subwoofer dimension is the only thing I'm unsure about when it comes to net vs gross volume.

Thank you. You've clarified what is feasible and what is not.

 

[slim2fattycake 10+ year member]

These are opinions and everyone has one. Just do it and then you will know. I see no problems with what you want to do except added obstruction and turbulence to the path of the new port. You might not even hear a difference with or without the old port panel there. However, you could beat the old panel out.

 

[MisterDeadeye 10+ year member]

Great. I was thinking the port might be an issue, but I just didn't know. I'll have to see if I can remove the port. As far as the NET volume, that would be accounting for the woofer displacement?
I will measure the port and then subtract its area from the total. The subwoofer dimension is the only thing I'm unsure about when it comes to net vs gross volume.

Thank you. You've clarified what is feasible and what is not.

When I was referring to net, I guess I should have just said gross. I just mean the gross volume after you take the port out. When you're trying to calculate the actual chamber's volume when designing a box, though, net usually refers to the chamber, ie., after accounting for the port and sub displacement.

If the box is put together simply, meaning no sides are extended past each other, and there isn't a double baffle, no 45s or other bracing, then to make it easier on yourself, just measure the external dimensions and I(or whoever posts before me) can calculate the gross internal volume.

 

[DBz Hertz 10+ year member]

These are opinions and everyone has one. Just do it and then you will know. I see no problems with what you want to do except added obstruction and turbulence to the path of the new port. You might not even hear a difference with or without the old port panel there. However, you could beat the old panel out.

I'm definitely going to take my mini sledge to that port wall. Hopefully it plays nicely.

 

[DBz Hertz 10+ year member]

When I was referring to net, I guess I should have just said gross. I just mean the gross volume after you take the port out. When you're trying to calculate the actual chamber's volume when designing a box, though, net usually refers to the chamber, ie., after accounting for the port and sub displacement.
If the box is put together simply, meaning no sides are extended past each other, and there isn't a double baffle, no 45s or other bracing, then to make it easier on yourself, just measure the external dimensions and I(or whoever posts before me) can calculate the gross internal volume.

Gotcha. I don't have the box with me now, but the height is 17", depth is 17", width is between 39.75" and 40". According to RF Woofer Box Wizard, I'm looking at ~5.32 - 5.35 cu. ft. total gross volume. I'm not sure if that 1/4 inch makes too much of a difference... I just know that the width wasn't quite 40", but within a quarter inch.