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Discussion Starter #1
Ok, for those of you that have been following some of my related threads, I am still torn on whether to just port my current Hertz ML2500 or grab a to be determined 12 incher.

I have been looking into building a ported box but I am having trouble coming up with the proper specs. I have winisd beta that I have been using and I also have the owner's manual specs too. When it comes to the sealed box recomendations from both they are almost identical which is what I would expect from a top sq sub manufacturer. Where it differs greatly is in the ported box recomendations. People here have told me that winisd is the best to go with but my installer (who I trust) says go by manufacturer recomendations. The manufacturer specs says 0.842 ft3 with a 3.1 inch port that is 9.6 inches long. Winsid says optimal would be ~1.36 ft3 with a 4.08 inch port that is 32.56 inches long. The owners manual doesn't give a port frequency and winisd is tuned to 26.49 Hz.

My goals are to get more sub extension. I want to feel this subwoofer. Which box setup should I go with or are there other suggestions? This is the first time attempting a ported design and actually only my second box. Any help is greatly appreciated. Oh, and if this will not give me what I am looking for let me know that too.
 

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Discussion Starter #2
Nobody has any suggestions? For the record, it is the port width and diameter I am most concerned with getting right. Well, I guess the size of the box is just as important. Also, I am looking for a fairly flat response ideally down to around 30 Hz with this box.
 

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winISD does a good job, but sometimes thier initial suggested settings are on the large size. input the manufactures recommended settings and look at the curve and see if it is any good.

I never like 3" ports for large diameter subs. usually port velocity is through the roof. the 4" port will be, more then likely, better.

make sure you check cone excursion too. if the box runs out of xmax at 40 hz(as an example) well below the power you are giving it, you may have to alter it slightly.
 

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Discussion Starter #4
winISD does a good job, but sometimes thier initial suggested settings are on the large size. input the manufactures recommended settings and look at the curve and see if it is any good.

I never like 3" ports for large diameter subs. usually port velocity is through the roof. the 4" port will be, more then likely, better.

make sure you check cone excursion too. if the box runs out of xmax at 40 hz(as an example) well below the power you are giving it, you may have to alter it slightly.
Thanks for the reply. I was going with the 3 inch port idea because that was the suggestion given in the owner's manual. Also, from my readings doesn't a larger diameter port require a much longer port? I am also considering using a flared port which is supposed to pretty much eliminate port noise.

As for the last part, I am unsure how or where in winisd you get that info on cone excursion at a given frequency. The last thing I want to do is fry this sub trying to do this.

When it comes to ported box design does it really matter if the port is on the same side as the woofer? I would also ideally like a straight port for ease of build. From what winisd states that would be impossible because of the port length it suggests. Does the program also take into consideration the area taken up by the port(s) when it comes to box dimensions suggestions? I assume such a long port would take up a fair amount of the box volume within the box. Sorry if these are nube questions but I am a nube when it comes to building sub boxes.
 

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Yes larger diameter will be a longer port.
The drop down box, cone excursion
No, it does not take port volume into account

Sent from my Motorola Electrify using Tapatalk
 

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In my opinion from my experiences with box building and box recommendations from manufacturers, they tend to base their suggestions off of a balance between nice output and tonality or response, depending on your specific needs this can be altered for higher performance and more "satisying" results, as we all know lowering tuning of the port will yield a longer roll off and flatter response, not to mentionm greater low frequency extension. increasing the port will help with port velocity, as will flared ports,

if your preference as i currently see it, is great low frequency response with a high level of accuracy and sq in mind, Id suggest building a slightly larger box, with a slightly larger port (4" sounds good, i also would use the 4" port over the 3" from my experience) and a lower frequency for the port tuning. The best box I have made to date for my 12" fi q was 2.65 before sub displacement which was .15 so essentially 2.5 tuned to 27.5hz with a slot port that was flared and 45's in all corners as well as rounded edges in the port. the box's port was fiberglassed, and there was also window bracing. the box was huge, but I never had a better box for lows, while retaining a high level of output and a very flat response.

SO back to your subwoofer. I havn't had a chance to suggest a size based on your specs. If i get a chance soon to do so i will w/o knowledge of trunk or hatch volume. But taking a rough estimate, i'd shoot for around .95 - 1.1 tuned to 27 - 30hz depending on output vs. flat response adjusted to your liking. don't half ass any box, Regardless of what it is, it's size, and design, use suffiecient amounts of glue (i make sure i see it squeeze out a small amount when clamping, if it doesn't take clamps off and apply more before securing. always use clamps, never just use screws or nails. always brace ported boxes, and always put 45's in corners and round over edges. following these steps will ensure a great constructed box. as far as caulk is concerned, I never have used it unless it was a sealed box simply for the fact it is cosmetically unappealing in the port, if i ever questioned a seal it was fiberglass resin for me.

don't use gorilla glue as the bonding agent affects the seal during its cure, think of it like wood glue wood as a sandwich vs tite bond which meshes the two pieces as one.

I am writing a lot because its early, im at work where i have tons of downtime, I was once in your position of knowledge which can be frustrating, I havn't contributed in awhile, and I love box building.

Someone once told me, with experience comes knowledge. Knowledge is power.
 

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X2 very good write up!

Sent from my Motorola Electrify using Tapatalk
 

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I am thinking of building a ported box for my 12W6V2 to compare to a sealed box.
I found a calculator to give port length for tuning in a certain size box and Hz.

The calculator did not want any info on the speaker?? Should it ?

I came up with 1.9 cu ft box fits best in my F150.
1.5" x 13" slot port and the lengths came up from 18" to 28" for various tuning.

Well my question is should the calculator want info on the speaker for this length?
Thanks
 

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Discussion Starter #9
In my opinion from my experiences with box building and box recommendations from manufacturers, they tend to base their suggestions off of a balance between nice output and tonality or response, depending on your specific needs this can be altered for higher performance and more "satisying" results, as we all know lowering tuning of the port will yield a longer roll off and flatter response, not to mentionm greater low frequency extension. increasing the port will help with port velocity, as will flared ports,

if your preference as i currently see it, is great low frequency response with a high level of accuracy and sq in mind, Id suggest building a slightly larger box, with a slightly larger port (4" sounds good, i also would use the 4" port over the 3" from my experience) and a lower frequency for the port tuning. The best box I have made to date for my 12" fi q was 2.65 before sub displacement which was .15 so essentially 2.5 tuned to 27.5hz with a slot port that was flared and 45's in all corners as well as rounded edges in the port. the box's port was fiberglassed, and there was also window bracing. the box was huge, but I never had a better box for lows, while retaining a high level of output and a very flat response.

SO back to your subwoofer. I havn't had a chance to suggest a size based on your specs. If i get a chance soon to do so i will w/o knowledge of trunk or hatch volume. But taking a rough estimate, i'd shoot for around .95 - 1.1 tuned to 27 - 30hz depending on output vs. flat response adjusted to your liking. don't half ass any box, Regardless of what it is, it's size, and design, use suffiecient amounts of glue (i make sure i see it squeeze out a small amount when clamping, if it doesn't take clamps off and apply more before securing. always use clamps, never just use screws or nails. always brace ported boxes, and always put 45's in corners and round over edges. following these steps will ensure a great constructed box. as far as caulk is concerned, I never have used it unless it was a sealed box simply for the fact it is cosmetically unappealing in the port, if i ever questioned a seal it was fiberglass resin for me.

don't use gorilla glue as the bonding agent affects the seal during its cure, think of it like wood glue wood as a sandwich vs tite bond which meshes the two pieces as one.

I am writing a lot because its early, im at work where i have tons of downtime, I was once in your position of knowledge which can be frustrating, I havn't contributed in awhile, and I love box building.

Someone once told me, with experience comes knowledge. Knowledge is power.


Thanks for the great readup. It was quite informative. I am kind of in a tough spot however due to my size restraints. I want this thing completely out of sight but I also need to keep it relatively simple too. Round over edges are nice but I am new to a router and the fact that it is doubtful anyone would see it here makes me think that would not be of much value in this instance. If I do go for more style down the road I will likely change the entire rear end design around and do a true false floor back there. That is on the back burner as of right now however. I need to make sure I have the right sub for one thing first.

What really has me confused is the port lengths required when I go to a larger box. I finally found a site that will allow me to full change all parameters on the box but it doesn't ask for any driver specs? I think this is the same site that the guy below is talking about. If I go to a 4 inch port, the port length is ridiculously long and I have no idea how I'd fit it in the box. Also, longer port means more port area means even bigger box. i also have never done anything with fiberglass although I am going to need to start next summer when it warms up. I have dash speaker pods to build but that is another story in itself.

You said you might give me some numbers for this if you ahd more info. Well, I just measured and it looks like my absolute max dimensions without changing a number of things that I don't want to change are 24 inches x 14 inches by 9 inches of depth. I do not have a trunk as this is a 2010 Toyota Rav4. I think all of my info is in the opening messege for this thread.
I appreciate any and all help you can offer with box parameters.
 

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I am thinking of building a ported box for my 12W6V2 to compare to a sealed box.
I found a calculator to give port length for tuning in a certain size box and Hz.

The calculator did not want any info on the speaker?? Should it ?

I came up with 1.9 cu ft box fits best in my F150.
1.5" x 13" slot port and the lengths came up from 18" to 28" for various tuning.

Well my question is should the calculator want info on the speaker for this length?
Thanks
Doesnt matter. The box is tuned to a specific freq. Doesn't matter what sub is in it
Sent from my Motorola Electrify using Tapatalk
 

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Discussion Starter #11
Doesnt matter. The box is tuned to a specific freq. Doesn't matter what sub is in it
Sent from my Motorola Electrify using Tapatalk
Good to know as I was wondering this as well. The combo of the box and tuning frequency will create the frequency plot and that would require the sub parameters. I take it the box size and desired tuning frequency of the port is all that is required. They are related to each other and determined by the sub's parameters.
 

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The port of a ported box is based on box size and port diameter/length. The sub installed had no effect on it. Now, that is not to say that the tuning has no effect on the final outcome

Sent from my Motorola Electrify using Tapatalk
 

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Discussion Starter #13
Ok, I think I have decided something here but I want to make sure of one thing first. I have come to the conclusion that I just don't have the room for a ported box and the complication of the tubes make it even more difficult to get the box volume correct. I have read that a sealed box always gives you a more sq sound compared to a ported box. I know that one will open up a can of worms...

The current box I have my ML2500 in is a sealed box and it was my first attempt. I'll be honest, it isn't a very good box and it is definitely leaking around the baffle where it meets the rest of the box. I had the speaker hole too large so I ripped it off and replaced it. The surface was uneven and hense it is leaking. I think this is killing my output a little? Is this true? Anyways, I am pretty much down to getting a 12 incher to replace it but don't have the cash to do so at this time. I am thinking about rebuilding a new sealed box for my ML2500 but I am going to go alot bigger this time. I looked at the spl plots for my size box versus the size I am planning on building and it appears to have alot more output down low which is what I am looking for. The manufacturer's recommended sealed size for my sub is around .67 ft3. The one I have now was exactly that but I didn't take into account the sub displacement so it is too small actually. I am going to make this new box about 1.2 ft3 after taking into account the sub displacement. This would give a qtc of .6293. By the look of it it should yield approx. another 1-2 db around 30 Hz or so. My question is will this cause damage to the sub being in a larger box? I am slightly overpowering with 800 watts rms too (rated for 600 rms).

By doing this I would be able to move to a 12 inch without having to completely rebuild the box again. I would just have to enlarge the sub opening to fit. Is this a good idea or just a waste of time in everyone's eyes? If nothing it would give me a box that I know is completely sealed. What does a leaky sealed box do when it comes to ouput/sq anyways? Sorry if this is kind of a noob question. Oh, I have determined that 1.2 ft3 is about as large of a box as I can do.
 

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Discussion Starter #14
I guess if I had a change of heart with this box I could always port it after the fact too instead of going with another sub. I just wish it was easier to get the ports into this box. They would be so long that they would likely to have at least two elbow joints. I just wish I knew what it would sound like before I built it.
 

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I personally wouldn't go as large as 1.2cf. The sound is likely to be on the boomy side and you'd have to be careful with the power you're giving it. I would'nt go larger than .75cf max for sealed with 800 watts. I played with the models for ported. [email protected] or [email protected] looked good IMO. You can use a 1.25" x 10" slot port in lieu of a 4" round port.
 

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Discussion Starter #16
I personally wouldn't go as large as 1.2cf. The sound is likely to be on the boomy side and you'd have to be careful with the power you're giving it. I would'nt go larger than .75cf max for sealed with 800 watts. I played with the models for ported. [email protected] or [email protected] looked good IMO. You can use a 1.25" x 10" slot port in lieu of a 4" round port.
Ok, I took those numbers to bcae.com's speaker box volume's calculator which is the only one that I have found that can really play with all of the different parameters for ports and box volume. I have used winisd and ajported but as far as I can tell neither allow you to truly move all of those numbers around (maybe I am just not edjucated enough in these matters). According to my findings, the 1.25 ft3 box would just be too large for my dimensions. It would require a box 30 inches long and I only have 24 inches roughly. I could go with the second 1 ft3 option when it comes to overall box size BUT once again how the hell do I get the port in it? Even if I use a 1.25 x 10 inch slot port as you suggest, the port length has to be 34.4 inches long! The box can only be 9 inches deep max which gives no room behind the sub at all. It would be quite the labrynth in there to get that kind of length. You also can't use the back wall as a side for the port or can you? If you can't as I think then there would be even more turns in there. If I can get away with a 3 inch port, the length would only have to be 17.4 inches tho which would be alot easier and also shrink the box down to around 24 inches long which is exactly where I want to be. If I were to order up a 3 inch flared port from PE would that work and not cause issues? Even 17 inches would prove challenging in this box. Maybe you have some other ideas that I have not thought of.
 

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Ok, I took those numbers to bcae.com's speaker box volume's calculator which is the only one that I have found that can really play with all of the different parameters for ports and box volume. I have used winisd and ajported but as far as I can tell neither allow you to truly move all of those numbers around (maybe I am just not edjucated enough in these matters). According to my findings, the 1.25 ft3 box would just be too large for my dimensions. It would require a box 30 inches long and I only have 24 inches roughly. I could go with the second 1 ft3 option when it comes to overall box size BUT once again how the hell do I get the port in it? Even if I use a 1.25 x 10 inch slot port as you suggest, the port length has to be 34.4 inches long! The box can only be 9 inches deep max which gives no room behind the sub at all. It would be quite the labrynth in there to get that kind of length. You also can't use the back wall as a side for the port or can you? If you can't as I think then there would be even more turns in there. If I can get away with a 3 inch port, the length would only have to be 17.4 inches tho which would be alot easier and also shrink the box down to around 24 inches long which is exactly where I want to be. If I were to order up a 3 inch flared port from PE would that work and not cause issues? Even 17 inches would prove challenging in this box. Maybe you have some other ideas that I have not thought of.
BCAE's volume calc is nothing compared to winISD. if you know how to use winISD, it will give you are much better idea of what a box will sound like.

if you want to tune it low, then that is what you have to do . you want a shorter port, then you will have to live with a higher tuning freq.
 

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Unless you have some way to seriously flare the port to create some kind of an adverse pressure gradient, there's no need to tune your box for a 12' woofer with a long 3" port. It may sound good when you apply a few watts, but at high power and high excursion, that port won't pass enough air to work effectively. It'll act like a noisy leak and the woofer will operate as if it's in leaky sealed box. When that happens, there's no benefit in using the port--only detriment. You'd be better off using a smaller woofer in a vented box or just sealing the box for your 12" and using EQ to get back what you'll miss.
 

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Discussion Starter #19
Unless you have some way to seriously flare the port to create some kind of an adverse pressure gradient, there's no need to tune your box for a 12' woofer with a long 3" port.This is for a 10 inch sub not a 12 inch although I am considering a 12 if this doesn't work for me. It may sound good when you apply a few watts, but at high power and high excursion, that port won't pass enough air to work effectively. It'll act like a noisy leak and the woofer will operate as if it's in leaky sealed box. What exactly does a leaky sealed box sound like? I know for a fact my current box is leaky. I just don't know how much it is leaking. What are the.characteristics of a leaky sealed box. Do they sound boomy, have a whistling sound or just lack output at higher output levels. My current box has the latter problem. At low output it doesn't sound too bad at all.When that happens, there's no benefit in using the port--only detriment. You'd be better off using a smaller woofer in a vented box or just sealing the box for your 12" and using EQ to get back what you'll miss.
Thanks for your response Andy. I always appreciate your input. If you (or anyone else for that matter) can answer the questions I put into your quote I would greatly appreciate it. Maybe I should TTY building another slightly larger completely sealed box first and see if that solves the problem. BTW, what is the general output difference from a comparative 10 inch to a 12 inch if they are box in manufacturer's suggested sized sealed boxes? If all else is considered equal. I know there are other factors involved but I am just curious if it can be quantified in some way.
 

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You can make it work with your dimensions if you incorporate a side-firing port. I sketched it up with a 7.5 x 1.5 slot port 27.64" long (approx. 31hz tuning). The slot port could run the width of the box at the top or bottom and turn down (or up) the opposing side. This leaves plenty of room above or below the port for the speaker. After subtracting the port displacement you're left with approx. 1.06cf net internal volume (If my calc's are on par). The response graph showed a slight bump above tuning up to 100hz or so with a -3db of around 27.6hz.

As to your questions about leaky enclosures, any of the conditions you mentioned could be present depending on the shape, location and severity of the leak.
 
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