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musgofasa

3 SSA Evil 18s B Pillar wall 2002 Suburban Enclosure opinions wanted

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Your question was which alignment.  You provided 3 choices.  That was 86'd to two choices.  Then a discussion of compromises occurred for which you offered no insight as to which way you want to lean.  Generically staying simple ported was discussed and it seems logical.  No one here would assume with you touting 27 years of experience that a discussion of port size on a simple box would be necessary.  We even see you come to the right conclusion:

On 9/16/2016 at 9:45 AM, musgofasa said:

If the models are any indication at all then a ported box would be the best option for sure.....at 30hz the output is identical. My concern is what will load best into the small space left in the cabin....seems like the BP would move a lot more air but I'm not sure really

The only strange part is the last part of the post.  Tells us something.  Us readers of your thread see that you started a thread hoping we would all support the 4th order BP that was referenced elsewhere and when we didn't you still tried to push it.  Every post that states to look into a different alignment you respond with further 4th order BP questions.  Considering that isn't a logical alignment for the build it is hard to be constructive.

 

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You asked for opinions.....we gave our opinions....you obviously didn't give any rats ass as to how to interpret any of it. I have a lot of experience myself, but we aren't having a who can piss further contest. Most of your responses to anything did give everyone only one perception, you really want to build some sort of a bandpass. Never did I ever see you put forth as much effort toying with a ported enclosure nearly as much as bandpass. Asking for opinions with a closed mind is kinda arrogant.

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Couldn't help but notice, you said in your original comment you just got your 3rd 18 in this week, and was starting a new build, then 1 comment down talking to Arron you said you where still waiting on the 3rd evil, so which is it, do you have the subs or not?

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BillyJack: 2 of the subs came in a couple months ago. Scott decided to go with 3 since we already had the amps. He told me the other day the third one should be in that week according to SSA and I posted this a few days later expecting it had arrived. When I asked he said it still hadn't come in yet :-(

M5, Jay-C76: here's the thing....you call me arrogant but obviously aren't reading your own posts. I despise arrogance and both of you condescendingly dismissed one idea without offering any constructive input. I tried to ignore it and even gave feedback on what I saw with a ported design including asking "how would this be affected loading such a large enclosure into a smaller cabin space?" (Or something close to that). I also said I didn't like how huge and long the port would need to be. The reason for that is 1)port velocity and 2) tuning low enough to flatten the response. That's what I'm seeing when I model these subs in a ported enclosure. The peak output in the model is irrelevant. Tuning will require tweaking after it's installed. I know this. I came on here to ask for ideas/opinions on using such a large space to take advantage of what I have. Like I said, "what would you do if someone gave you this build?". So far neither of you has offered anything of what you would do only that you wouldn't do a 4th BP. Tbh I would much rather do a series tuned 6th order. I've even drawn up an 8th order since I've had so much time to overthink this while waiting on the subs to come in. I don't like the group delay in either case but I know I can make better use of all that space than a standard "recommended airspace" ported enclosure. It feels like a waste to use 1/3 of my available space and have a box with a huge slug of a port crammed up against the seats to net only 3-6db over a sealed alignment. It looks like 21cu ft is a sweet spot with a 300ishsq in port tuned around 30hz but that port size has higher velocity than I like. Doubling the port looks great except it isn't practical. 

I've asked 4 or 5 people who I trust and who have built a lot of very high output systems for opinions but none of them were familiar with these particular woofers. 1 said to go VERY large ported which makes sense but doesn't tickle me when modeled. This may be because I don't know what to expect when loading a large ported enclosure into a small cabin (hence my asking questions). The others all said that a 4th BP would be more forgiving and easier to tweak than a higher order. I do agree with this. I love doing small 6th and 8th order boxes but at this scale, if adjustment is needed it would be a nightmare I think. If anyone thinks they have an idea to reduce the workload on a higher order bandpass I'd love to hear what you've done to make it so. I'd also welcome opinions on specs to model to compare what is known prior to cutting up hundreds and hundreds of dollars worth of wood and time.

i'd like to thank everyone for offering advice here but if your only input is going to be to tell me how not to build please stay out of the thread so other people won't be discouraged and unwilling to post for fear of an argument. It should be obvious I'm putting some effort into this and if I'm going to type a book like this only to get a childish one word response like "K"....well then pottasium to you too! So you think ported is the best bet. Great! Tell me more. Not why it's better but how it's better. How to get what I want out of the build with that alignment. Something I can work with that someone with my experience might not already know. 

Here's couple recent builds I've done in case you want to see some work. The first is 4 Ethos 15s on a Taramps 8k...just posted a 153.9 at the Sundown show. I don't like the wires hanging but it was his request in a temporary setup

. The second is 4 15s in an S10 ext cab. Roughly $1500 total install that sounds phenomenal. Very clean and articulate. I like the sealed alignment here but it's not very loud at 147 for what it is.

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Edited by musgofasa

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And here is something more like what I hope this install will look like when finished. I like using mirrors....yes we did this one a VERY long time ago lol 

image.jpeg

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I see, your just doing a build for someone. And sorry about your experience here, they're really are some good guys here that can help. I have only had one wall in my life, and I hired it out to much for me, I'm more of a trunk guy my wall was a lot of trouble, it was like trying to keep a race car going, constant maintenance. 

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6 hours ago, musgofasa said:

I came on here to ask for ideas/opinions on using such a large space to take advantage of what I have. Like I said, "what would you do if someone gave you this build?"

 

Simple, a simple ported.  You have modeled, so it is easy to see how much excursion will be at what power.  That will determine the max size/gain.  Port area we could surely discuss, but it is a function of solely managing port velocity and what your customers' expectations will be.  I'd err on the side of a lower velocity personally that may not be what your customer wants, but I wouldn't take a customer that didn't understand I won't make that compromise.  Obviously we don't know your interaction with him so if you want to discuss that you need to be more specific on what.

6 hours ago, musgofasa said:

The others all said that a 4th BP would be more forgiving and easier to tweak than a higher order.

While that is true, a standard ported enclosure is also more forgiving.  Considering you are building this in one shot the KISS principle is worth following.  You also referenced musical which of course pushes this way.

I read your book, think the problem is simple.  You are looking for golden rules, rules of thumb or other things to follow.  This doesn't exist.  In the installation you propose there are not so many things to balance so if that is what you want to have a more direct conversation on then you need to ask.  Just like the install should be KISS the thread needs to be as well.  If you want to discuss something, start the discussion.

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1 hour ago, Billy Jack said:

I see, your just doing a build for someone. And sorry about your experience here, they're really are some good guys here that can help. I have only had one wall in my life, and I hired it out to much for me, I'm more of a trunk guy my wall was a lot of trouble, it was like trying to keep a race car going, constant maintenance. 

Thanks Billy Jack,

That "constant maintenance" would be nice to avoid but yeah I can see it coming lol. I did a lot of walls back in the 90s but back then woofers weighed 20ish lbs and we did single baffle 5/8 and 3/4" wood and either none or only a few batteries. Mostly sealed boxes and a very few bandpass and up until the late 90s no ported boxes to speak of. I worked on a van for JL Audio that was a 6th order BP for 12 15s and even that was pretty well built and done. These days it's a whole other animal with 100lb+ subs and some guys running 24 batteries and 4+ alternators etc. Amazing how much goes into these monstrous builds. Reinforcing sheet metal and welding stripper poles in to keep from tearing trucks apart...Alma definitely stepped up the game lol. 

1 hour ago, ///M5 said:

Simple, a simple ported.  You have modeled, so it is easy to see how much excursion will be at what power.  That will determine the max size/gain.  Port area we could surely discuss, but it is a function of solely managing port velocity and what your customers' expectations will be.  I'd err on the side of a lower velocity personally that may not be what your customer wants, but I wouldn't take a customer that didn't understand I won't make that compromise.  Obviously we don't know your interaction with him so if you want to discuss that you need to be more specific on what.

While that is true, a standard ported enclosure is also more forgiving.  Considering you are building this in one shot the KISS principle is worth following.  You also referenced musical which of course pushes this way.

I read your book, think the problem is simple.  You are looking for golden rules, rules of thumb or other things to follow.  This doesn't exist.  In the installation you propose there are not so many things to balance so if that is what you want to have a more direct conversation on then you need to ask.  Just like the install should be KISS the thread needs to be as well.  If you want to discuss something, start the discussion.

Now we are getting somewhere M5 

I've modeled this thing in anywhere from 18 to 50 cu ft just to see what comes of it and here are some results....maybe you could offer which one of these seems like the best compromise.

1) with the power I am putting on them they never come close to reaching xmax above 22 or 23hz in ANY size box and I plan to run a subsonic filter to avoid this being an issue. That being said, if I go a little smaller (19 cu ft) they don't reach xmax until 19hz. I am comfortable with 25hz even as this guy like old rock music and the kind of bass that takes your breath away as much as the hair tricking 25hz stuff. I will be there with him for the most part to make sure his right wrist doesn't get too happy with the low stuff anyway. At least long enough to see that he doesn't just arbitrarily blow woofers. (fingers crossed you know how it is when it's not your own build). 

So I have another friend with some custom 18s in a blazer....2 18s in 21 cu ft and a very large port. Port velocity below 20m/s. It sounds fantastic and at 45hz will nearly close my throat. Hair tricks aren't quite as big as others out there but it's so much fun to play with. I figure the 3rd 18 in our build will probably make up for the slight loss at the very low frequency and get us the hair tricks we want if I follow the same ideas for building the box. 

I know "rules of thumb" are not legitimate ways of building anything. Like I said earlier they exist for a reason. If you reverse engineer enough successful builds there are a ton of them that fall close enough to them to make it noteworthy is all. That being said, I have found no few builds where the port area is huge and far more builds where it is not nearly so large. 

at 22cu ft the port becomes an issue. I like the curve better if I tune lower....like 26-28hz although at 30-32hz in this size it doesn't look too bad. The problem is that to get port velocity down I need a port of 390sq inches that is 36" long.....that seems excessive to me but I don't have any real experience with ported enclosures this size in a wall....the area doesn't bother me but the 36" length does.

If I go 30 cu ft I can tune to 28hz and the port is a bit bigger at 480sq inches but is still 36" long ....still seems very long to me.

This is the compromise I'm referring to....I'm not sure where the best line to draw is going to be. The cabin will be roughly 30cu ft in front of the box and of course it will load differently with doors/windows open/closed and people in the seats etc. I'm not sure how that will effect the performance. I'm also wondering, if I go with straight ported, is the long port like this is a normal way to build with these high excursion, high power subs? Hell maybe that's not that long when you compare percentage of port volume to enclosure total. The 4 15s above are in 12cu ft and the port is only 14" long. Also with the airspace....my thoughts are that if I go too large I will hit a serious point of diminishing returns. 22 cu ft wouldn't even require going past the second row hump lol. I'll have 10 ft of space at the back of the truck to play with. That would actually be fun for doing some lights and mirrors etc. But I want to make sure I'm not wasting that space if it can help. 

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I believe I actually saw that van at finals in Lebanon Tennessee back in the 90's, but I could be wrong but I remember seeing a van with a bunch of 15's in it. The one I saw was white and they done demo's with it to promote JL. I was there competing so I didn't pay much attention I just remember people waiting for a demo. I still run JL myself I have a 13w7 I just threw in my wife's car I need to get a ported box for it and the other sub I have. 

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I'm inclined to go with the ported enclosure more and more.....Aaron's suggestion was ported at I think 7.5cu ft per sub originally and when I look at models the ported box gives me more low end with a flatter response curve for sure. These cones are pretty heavy and of course they are 80+lb subs so maybe driving that gigantic slug of a port is ideal. With the super clean amps running them I don't think I'll have any problems with burning them up either. Now to decide just how big to make the enclosure......Even at 50 cu ft I don't run out of excursion so what do you guys think is the best way to determine where to draw the line?

 

 

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It's been my experiences that it's okay to go larger than recommendations per sub as long as you really watch the port velocity. Modeling kinda gave me an idea as to what was way to low on velocity. With those subs you could even set your limits on preferred velocity a little high from and audible stand point. With that much output the chuffing with be very hard to hear.

With that in mind, the reason I would set the bar higher is that when going with a larger than recommend enclosure there's a point where you won't have enough velocity to keep the right amount of back pressure inside the enclosure causing the sub to be more prone to bottom out on the lows such at anything around 32hz & lower.

One thought, and I am just tossing this out there is that you could just design a single enclosure for each of the subs. Stacking the 3 side by side and the front baffle would still give the illusion of a common chamber but the internals & port would be so reinforced on the inside it would diminish any flex from having such a large port.

Designing a single enclosure for a single sub would be a lot easier to control your design. If you ever had any failure from one sub it would keep the others from shreading themselves apart as well being that there are an odd number of subs in the design.

As far as a velocity cut off on the min, I really can't say. I use a different program when I model & design. But on mine I would try to not go lower than maybe a 6% mach. Without modeling this myself it may even go higher. Increasing the area would lower the percentage bit also makes the port longer, but you already are aware of that. In my opinion a 36" long straight port really isn't that bad. I've built & seen some that were well over 50" and without sacrificing anything other than space. If you got it use it...lol

Tuning lower can flatten things out on the response curve but generally I don't like going lower that 26hz to achieve that. The actual gain in the cabin on tuning would have to be answered by the meter. I know in my little ranger on just a blow through, if I tuned the enclosure @ 26hz. my peak would be at 32hz. which for me was awesome because I listen to a mix of rock & rap. With a flat response curve I could play a variety of songs during demo and still turn a lot of heads.

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On 9/18/2016 at 2:58 PM, musgofasa said:

Now we are getting somewhere M5 

It is the same as before, you are just reading it in a positive way instead of negative. 

On 9/18/2016 at 2:58 PM, musgofasa said:

1) with the power I am putting on them they never come close to reaching xmax above 22 or 23hz 

There was no number 2) btw...either way, first question you need to find out is what your customer will play on them.  In the rest of the post it surely sounds like nothing low in which case tuning higher makes a ton of sense to give yourself some gain where he will want it.

On 9/18/2016 at 2:58 PM, musgofasa said:

So I have another friend with some custom 18s in a blazer....2 18s in 21 cu ft and a very large port. Port velocity below 20m/s. It sounds fantastic and at 45hz will nearly close my throat. Hair tricks aren't quite as big as others out there but it's so much fun to play with. I figure the 3rd 18 in our build will probably make up for the slight loss at the very low frequency and get us the hair tricks we want if I follow the same ideas for building the box. 

I know "rules of thumb" are not legitimate ways of building anything. Like I said earlier they exist for a reason. If you reverse engineer enough successful builds there are a ton of them that fall close enough to them to make it noteworthy is all. That being said, I have found no few builds where the port area is huge and far more builds where it is not nearly so large. 

I like 20, but you don't have to go that low in this build.  Output will mask the noise.

As for the rules of thumb, you'd be surprised how many fall way outside of them.  They are a shortcut for the uninformed and should be taken with a grain of salt at best.  Science doesn't lie, art confuses things.  I know which I prefer to follow...

On 9/18/2016 at 2:58 PM, musgofasa said:

at 22cu ft the port becomes an issue. I like the curve better if I tune lower....like 26-28hz although at 30-32hz in this size it doesn't look too bad. The problem is that to get port velocity down I need a port of 390sq inches that is 36" long.....that seems excessive to me but I don't have any real experience with ported enclosures this size in a wall....the area doesn't bother me but the 36" length does.

If I go 30 cu ft I can tune to 28hz and the port is a bit bigger at 480sq inches but is still 36" long ....still seems very long to me.

I understand liking the curve better if you tune lower, but you actually considered the BP curve which is laughably bad so why so worried about the frequency on the ported enclosure?  36" isn't long.  

You are thinking about this completely wrong though.  Ignore port area and port length and instead solely focus on port resonance and port velocity.  The actual shape/size whatever is irrelevant.

On 9/18/2016 at 2:58 PM, musgofasa said:

This is the compromise I'm referring to....I'm not sure where the best line to draw is going to be. The cabin will be roughly 30cu ft in front of the box and of course it will load differently with doors/windows open/closed and people in the seats etc.

That is irrelevant.  Not a compromise.  You state wall therefore all of your designs suffer the same fate loading wise.  Sure there are differences mechanically due to the enclosure but if they are acoustically analogous then they are the same in that regard.

On 9/18/2016 at 2:58 PM, musgofasa said:

 I'm also wondering, if I go with straight ported, is the long port like this is a normal way to build with these high excursion, high power subs? Hell maybe that's not that long when you compare percentage of port volume to enclosure total. The 4 15s above are in 12cu ft and the port is only 14" long. Also with the airspace....my thoughts are that if I go too large I will hit a serious point of diminishing returns. 22 cu ft wouldn't even require going past the second row hump lol. I'll have 10 ft of space at the back of the truck to play with. That would actually be fun for doing some lights and mirrors etc. But I want to make sure I'm not wasting that space if it can help. 

Why is this not a concern in a BP to you?  Laws of Physics are the same and while the environment is slightly different it is easy to calculate exactlywhat that means.

I find it funny that you are worried that 36" for a large system sounds long, but are okay with 14".  14" for 3 18's sounds wicked nasty short to me.  

 

The reason for the negativity earlier is simple.  The 4th order BP buys you NO advantages here.  It is really not a good choice.  The problem is that you've "heard" from others that have had success what they like.  The bummer is none of them understand the success nor did they compare it with something else that would have worked better, yet they sing the gospel and you are happy to hear it.  The opposite is true here, you aren't eager to hear what I say so only "see" the negative instead of the reality which included a lot of positive.  Blame it on written/read word as it truly distorts reality to the eye of the beholder.  It is your eye, you can choose to see what you want.

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8 hours ago, ///M5 said:

There was no number 2) btw...either way, first question you need to find out is what your customer will play on them.  In the rest of the post it surely sounds like nothing low in which case tuning higher makes a ton of sense to give yourself some gain where he will want it.

I like 20, but you don't have to go that low in this build.  Output will mask the noise.

sorry...I had something in mind when I started typing that but must have gotten off track (it happens lol).....20 is typically what I shoot to stay under...I have gone as high as 30 without really noticing any noise in quite a few builds. I hear what the guy is telling me about his "music preferences" but then he also asked me to download a bunch of Decaf and DJSNT stuff so he could hear his favorite songs with the re-bassed versions. That tells me he is more likely to be abusive than he says or I train him to be so I know I need to not let him have his cake and eat it too.

8 hours ago, ///M5 said:

As for the rules of thumb, you'd be surprised how many fall way outside of them.  They are a shortcut for the uninformed and should be taken with a grain of salt at best.  Science doesn't lie, art confuses things.  I know which I prefer to follow...

I agree....I only suggest that when things do fall into those generalizations it isn't a bad thing. I also recognize that it's not a bad thing if they do fall outside of them.  As far as port area it would seem that the rule of thumb almost always keeps port velocity in a range I am comfortable with (almost)

8 hours ago, ///M5 said:

I understand liking the curve better if you tune lower, but you actually considered the BP curve which is laughably bad so why so worried about the frequency on the ported enclosure?  36" isn't long.  

You are thinking about this completely wrong though.  Ignore port area and port length and instead solely focus on port resonance and port velocity.  The actual shape/size whatever is irrelevant.

That is irrelevant.  Not a compromise.  You state wall therefore all of your designs suffer the same fate loading wise.  Sure there are differences mechanically due to the enclosure but if they are acoustically analogous then they are the same in that regard.

Why is this not a concern in a BP to you?  Laws of Physics are the same and while the environment is slightly different it is easy to calculate exactlywhat that means.

I find it funny that you are worried that 36" for a large system sounds long, but are okay with 14".  14" for 3 18's sounds wicked nasty short to me.  

This is where my concerns are being addressed for sure....whether BP or Ported. I have done thousands of sealed boxes including some extremely large ones but when I look at tuning and think of these gigantic ports I think of the "one note wonders" I've seen and how many times I've heard that result. Port velocity I definitely understand. It's easy to see on the model. But port resonance might be where my knowledge is lacking then. 

3-18s in 30 cu ft gives me just under 20m/s velocity with a 397sq in port 36" long tuned to 26hz and an F3 of 23hz and F10 of 19hz.....this may be tuned too low? Cone excursion shouldn't max out until 21hz (according to the model) and I plan to run a subsonic filter to limit that issue. The model shows a "first port resonance" of 187.22hz.....to be honest I'm not even sure what that means but if it is relevant to output it should be well above the high frequency cut off so I don't believe it would matter. Can you elaborate on what I might need to look at there?

And yeah....I have never built a huge ported enclosure....this will be a lot more than a monkey coffin for sure. in proportion to the smaller boxes a 36" port isn't really that long when scaled up. When i used to compete in SPL tuning at 52hz and the like we wanted the shorter port to try and eek out that last .1db but we aren't chasing that number in this install so I'm a little off on exactly how to proceed.

 

8 hours ago, ///M5 said:

 

The reason for the negativity earlier is simple.  The 4th order BP buys you NO advantages here.  It is really not a good choice.  The problem is that you've "heard" from others that have had success what they like.  The bummer is none of them understand the success nor did they compare it with something else that would have worked better, yet they sing the gospel and you are happy to hear it.  The opposite is true here, you aren't eager to here what I say so only "see" the negative instead of the reality which included a lot of positive.  Blame it on written/read word as it truly distorts reality to the eye of the beholder.  It is your eye, you can choose to see what you want.

It's easy for me to see the advantages of 4th order as 25 years ago i was one of the only people building them and i sold thousands of them....granted they were small enclosures that just worked tremendously well with the subwoofers of the day but I've had a lot of success myself with the design. Since the advent of subs with heavier cones and motors a lot of those old tricks have become obselete in a way. I know this and I want to learn the new tricks which leads me to think the 6th order and even the 8th I've built a few of might be good designs for the future of SPL but for now I agree...KISS definitely makes my life easier....if this were my own car sitting in my garage to be tinkered with whenever I wanted I would be going that route without question....testing and testing and testing....but this does need to be built and sent on it's way so I'm all about the easier build. Not to mention I can throw some beauty panels in there for a quick install and it will be so much easier to work on with a flat wall. Lifting 80+lb subs into a box and crawling inside are not appealing ideas lol. 

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The advantage of the 4th BP is that the box can be remote.  The other "advantage" is a horribly peaky response.

 

Port resonance is just like any other resonance whether it be modal or acoustic.  If it is too close to the range your driver is playing then you will need to make sure to notch it out of the response with electronics.

In your customers' case I would worry more about port velocity at listening levels than demo levels.  ie, no need to worry too much about the max velocity at max power, but more focus on ensuring it is low where he will focus on listening.  I still wouldn't get ridiculous with it at max power (if it were my car I like your target of 15-20) but don't get too carried away.

26Hz is REALLY low tuning in a car.  The benefit is a few Hz before roll off with the disadvantage of the peak you were going for with the BP being completely eliminated.  If your customer has a crap ton of music that just won't play nice on a 30-32Hz tuned box then fine, but otherwise there is no need to go that low.  It is already into the law of diminishing returns for making the response nicer and is just costing you output.  

Car audio is all compromises.  Glad you are finally off the ridiculous one of doing a 4th order BP.

 

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Not a big difference in 26 and 30hz really....raises F3 and F10 about 4hz to 28 and 23 which will likely not even be noticeable inside the cabin. Those 4 15s are tuned at 32 and will play into the 20s easily. I imagine if he really wants to focus on hair tricks we will just work out what frequency and which door/window to hold open and make sure to keep that in mind....tuning at 30 actually gains me about 3db of total output.....32hz tuning doesn't seem like much of a gain and the F3/F10 go up significantly....at least in the 30cu ft box. 

If I lower the size of the box the curves actually get a lot closer together but the roll off is steeper....this seems like that point of diminishing returns coming into play.....I'll play with both numbers a bit and see if I can find a sweet spot. 
Thanks M5.....giving me a lot to think about but now I'm getting somewhere other than spinning my tires :-)

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In my experience 26 to 30 will make a pretty decent difference in a car . I would shoot for closer to 30 

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Yeah....looks like 30-32hz is a magic number.....Would anyone feel like taking a look at it with their models and see if I might have missed anything here? My happy medium comes in at 28cu ft net with a 30hz tuning. Port is 405sq inches and 26.5" long with a port velocity of 19.4m/s at 29.19hz which should prove to move plenty of hair, towels and eyeballs I imagine......I can get another 1 or 2 db going with a slightly higher tuning but it sacrifices about as much as it gains......trying to decide if cabin gain will be more than I'm thinking and maybe tune a little higher to get the peak frequency up a little higher. What do you guys think? It looks to me like any bigger doesn't make more than a db of difference and as far down as 21cu ft only cuts off the low end extension some.......All in open air environment....loaded in a vehicle I imagine the low end will be stronger than the model which has me inclined to think maybe tuning at 32 or 33 might be an idea...don't want to go too high as I don't want it to be peaky and these 18s have a mighty low fs at 25.9......that's what I'm not sure about though. Thanks again guys

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There is a reason that the site/store recommends a tuning in that range.  I expect he would like it on the higher end of recommended, but again I know not his average listening music or desires other than what you've shared.

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What I've shared is all I know too lol...Talked to him at length last night and he agreed to tune it a little higher to make sure it sounded good with regular rock and Pop music. He will be using the decaf and DJSNT stuff for demos when he finds songs he likes that work well with what he has. Just wants to make sure it's got some bragging rights so I'm looking good with 30-32hz I think....have had success tuning at that frequency with quite a few builds of late. Just no walls recently to compare to. I think it should translate well. 

recommended "optimal" is up to 8.5 per sub which would be 25.5 for three.....when I model at that it doesn't look bad but I am not putting full power on them by any means so I'm thinking a little bigger certainly won't hurt. 28 total looks good and seems to be where the models run out of gains. Much bigger nets very little and only raises the frequency where xmax can be reached. 28 gives me a good size port to work with for the area I have where the subs/port must fit too. Seems straight forward after that. less than a half db either way if I go up to 35hz or down to 26 and 30-32 gives me an in the middle (smoother) response curve. 

I always want to do something more extreme or complex just because I have been doing this so long and people know me for building band pass boxes but in this case the ported box just works out better. I suppose thousands of watts on a 40ish cu ft gross enclosure with 800lbs of wood should be considered pretty extreme lol. 

at this point all the materials are here or on the way and the truck just got the A/C fixed last week....time to start tearing this thing apart and making sawdust! 

Thanks guys! Build log coming!

 

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32 minutes ago, musgofasa said:

recommended "optimal" is up to 8.5 per sub which would be 25.5 for three.....when I model at that it doesn't look bad but I am not putting full power on them by any means so I'm thinking a little bigger certainly won't hurt. 28 total looks good and seems to be where the models run out of gains. Much bigger nets very little and only raises the frequency where xmax can be reached. 28 gives me a good size port to work with for the area I have where the subs/port must fit too. Seems straight forward after that. less than a half db either way if I go up to 35hz or down to 26 and 30-32 gives me an in the middle (smoother) response curve. 

Half a db is irrelevant.  25-28cuft and 30-32Hz will be fine.

32 minutes ago, musgofasa said:

I always want to do something more extreme or complex just because I have been doing this so long and people know me for building band pass boxes but in this case the ported box just works out better. I suppose thousands of watts on a 40ish cu ft gross enclosure with 800lbs of wood should be considered pretty extreme lol. 

That is where most of the BP builds come from.  People doing something "different" which ends up being the same as the rest.  4th order BP boxes in general are less extreme in that they rarely if ever work as well as a standard ported.  Lemmings will do what they do though, glad you thought through this enough to do the right thing.

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Looking forward to the build log.

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Truck is coming either this weekend or next to strip down for Sound deadening. We have the mids/highs ready to go and all the wiring. 1 pair of 6.5s and one pair of tweets in the doors, 8" in the wall and a pod on the dash/A-pillar for another pair of tweets. Deck in the factory location and an Audio Control Three.1 going in either a custom center console cover or in the factory CD player location at the bottom of the dash. Box will have a mirrored front and be trimmed in with carpeted panels in the front. May even make the port removable in case we decide to play with tuning later on.

3 LP2250s, 1 LP2150,  and 4 batteries in the back. I figure I will make some custom rack with LEDs and possibly more mirror back there to show off when the doors are open. For electrical the stock alternator will be left in place and a bracket added to run the second alternator at 15.2 - 15.4 volts just for the stereo. I believe 370a.

Drawing up the box now so I can get some cut sheets going. We will be going to finals in KY in 3 weeks to talk to the guys at LP and with some of our friends. Hope to see some of you guys there! After that it's all about getting this thing finished! 

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Can't wait to see the build. You definitely have a knack for producing very nice eye candy. Glad you worked out the ported design I hope to hear this in person.

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