Triticum Agricolam
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Posts posted by Triticum Agricolam
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1 hour ago, Colby88 said:
Alright well he's gonna be pushing around 1500watts and like around 30hertz to 50hertz ya know I don't really know how far the band width goes so I don't want a gap in between tho. He just tired of hearing lows but he wants to have more "variety". He wants to keep his lows but still have high end.
So a fourth order bandpass box lets you trade bandwidth for efficiency. So to get the wider bandwidth your friend desires he is going to have to give up a lot of output. My suggestion would be a parallel-tuned 6th order bandpass. You friend would keep the low frequency output he is used to, but he would get a big boost up higher for a much wider bandwidth.
For specs I'd suggest 5 cu ft @ 28 Hz for the rear chamber and 2.5 cu ft at 55 hz for the front chamber.
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Forget everything you have learned about ratios. They are wrong as often as they are right. You are much better off designing the chambers independently of each other based on what you need the box to do.
How much power is your friend going to be running? That will determine how big you can make the sealed chamber.What kind of bandwidth does your friend want to get? What are the goals for the system? That will determine the size and tuning of the ported chamber.
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I've bought stuff from the Sundown yard sale on several occasions and have been happy with what I got.
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28 minutes ago, bcpballer64 said:
So, my stepdad has worked for the same farmer 27 years. The guys son also works on the farm, and he is a fuck stick. Do to his many fuckups he mostly handles the business side. My stepdad handles the operations, and the old guy is the old guy lol. So one of the sons fuck ups, he managed to bury an articulating tractor...to the fucking axles. Front and rear. I think it was a JD 9620. They had to have a crane come out to get it out. Some of his other crap, ripped the auger off a combine, dragged a grain trailer two miles to a field with the brakes locked, got loaded up, and dragged the mother fucked back, also overfilled a top dry bin multiple times. He's an idiot lol.
Lol, I think people like that are everywhere in agriculture. If nothing else they serve as good entertainment/warning to others :-)
I've gotten stuck more times this year than every before, and I'm not done yet. I know when to quit though and not make the problem worse. Here is what my neighbor's son did a few weeks ago:
That one sat there for a couple weeks and took a big track hoe to get it out!-
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2 hours ago, ShadeTreeMechanic said:
Holy smokes I thought the wheel fell off. Lol it doesn't look like a low spot there it it?
Lol, yeah it does look like the wheel came off. Where it happened is a bit of a wide draw bottom, its a spot I've already driven through about half a dozen times. Just hadn't driven over that exact spot yet, wish I hadn't. I figured I was fine then I noticed the tractor sinking in a few inches, looked back and saw the sprayer just drop. Whole thing happened in like 2 seconds.
I got out and just stared at the thing in horror and disbelief, thinking to myself "I can't believe this just happened...." I already gotten stuck a few times in the past couple days, but not like that.
2 hours ago, Karkov said:How the hell did the 4wd tractor not dig ruts but that thing almost fells through quick sand it looks like?! break anything on the "trailer" (im not sure what it is, sprayer?) That is sooooooo deep
That tire probably sunk down about 5 feet or so....it left a big hole.
The sprayer puts a LOT more pressure on the ground. The reason the sprayer sunk and the tractor didn't is the tractor weighs about 34,000 on eight 20" wide tires. The sprayer was full of fertilizer, which is heavy at about 11 lbs/gallon, so it was weighing about 25,000 lbs, most of which was being carried by two 18" wide tires.
Getting the thing out didn't turn out to be too bad. I drug a tank out there and pumped most of the fertilizer out of the sprayer. Then I just drove forward nice and slow. Sprayer was unscathed, thank God. I learned my lesson and only filled the sprayer half full from there on out and was able to get everything finished today.
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FML.......
To put how buried that thing is in perspective, here is what it looks like when its not in a mud hole:
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If you have the test leads wired to the inputs going to subs, that is going to tell you total power (both amps combined).
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Where did you have you + & - test leads attached to?
You are probably seeing combined power.
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How much power are you running?
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Awesome, glad to know it was an easy fix!
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Did you make sure they are wired in phase? Easy mistake to make.
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So is this a prefab box then?
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Its close enough, you may be giving up a little bit of output around tuning due to the smaller box, but I wouldn't lose much sleep over it.
How much port area does the box have? An undersized port will cost you a lot more output than the box being .5 cubes smaller than ideal.
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Amplifiers are not really my area of expertise, but here is my understanding. Adding more batteries will NOT allow you to turn your gain up any higher. It will just allow you to maintain the same level of output for a longer duration (with less voltage drop).
The reason is amplifiers have a maximum voltage they can put out (which is produced by the power supply section of the amp board). Once the output voltage reaches that max voltage this is when they start to clip. Adding batteries will not increase that max voltage, so you won't be able to push your amp any harder, it will just allow you to draw more current for longer.
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I just checked the link. It calculated I need an 8 inch port at 49 inches length. That's 1.5 ft^3 of my 2.5 available volume!!! How do I get around this?
Well unfortunately there really no way to "get around" it without paying a performance penalty somehow. Welcome to the difficult part of car audio enclosure design :-)
Whenever you are dealing with a situation where your space is limited, which is most of the time with car audio, the trick is figuring out what design compromises can be made that will have the least negative impact on performance. No matter what you do, performance is going to have to be sacrificed in some way, we just find to find the best way.
One thing you can do is decrease port area. This won't hurt performance at all at low volume, but at high volume it will eat your output for lunch. It can be quite detrimental.
Another thing you can do is reduce box volume, this will decrease output around tuning at all volume levels, but it will do so consistently, unlike reducing port area.
You can also tune higher, higher tunings require shorter ports, so you will save some space that way, also with higher tunings you can get away with smaller box sizes. The price you pay is decrease low frequency performance. Depending on the type of music you listen to tuning higher may or may not be a path you want to go down.
Lastly, you can reduce cone area, by either running smaller subs or running less subs. In your case dropping down to three SA-8s may be something to consider.
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Yeah with a single 3" port you would pretty much have a sealed box, whether you want to or not.
While 15 sq in per sub may sound like a lot, to put it in perspective Sundown recommends 8-12 sq in for their E-8 sub, and thats and 300 watt RMS sub. You are going to be (potentially) running 2.5 times as much power. At tuning all of the output comes from that port, you don't want to be choking it off.
I think your idea of a single 8" port would be great.
Here is a calculator that you can use to give you an idea of proper port size: http://www.carstereo.com/help/Articles.cfm?id=31
With high Xmax subs (18mm or greater) that calculator tends to error on the high side, but its a starting point at least.
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Good to know it can be done, I'll try to source some real Baltic birch and add bracing to the design, if it works well I may have a well drafted set of plans to share when I'm done
No prob.
When you are working on your design, make sure you use enough port area. It can be tricky to do with these smaller boxes. For a SA-8 on 750 watts I'd use no less than 15 sq in per sub.
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1/2 material can work well, but you have to do it right. First off, don't use MDF, use real baltic birch plywood, its a lot stiffer than MDF. Home Depot won't have it, you have to get it from a plywood supplier. I pay about $32 for a 5' x 5' sheet of it.
Secondly, you will need to brace it well. Try to keep unbraced spans less than 10".
I've built quite a few enclosures out of 1/2" material, it works fine as long as you approach it correctly.
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Since this is going under the seat of a pickup that makes it a tougher choice. If you are going to be using a DSP, I'd be inclined to go with the four SA-8s. You can use the DSP to fix their biggest drawback, which is peaky response. An alternative would be to use a couple higher power handling 10"s. A pair of FI SSD 10's would work well too, but then they would have to be down firing, which complicates things.
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Big question, how much power are you going to run? That is going to greatly affect what subs you should pick and how flat of response you can achieve.
Here are some things to think about:
1. Ported boxes boost output around tuning. Once you get about an octave above tuning, the port has no effect. So at 70 Hz a 25 Hz tune is going to sound exactly the same as a 32 hz tuning.
2. The larger you make a ported box, the more boost in output you get, but only around tuning. If you want smoother frequency response, making the box smaller is one way to do that.
3. If you care about frequency response, don't run 8" subs unless you can't fit anything else. The problem with 8" subs is if they have moderately high power handling (which for 8"s is anything above 300 watts RMS, IMHO) they generally have really stiff suspensions and high motor force to cone area ratios, both of these things are bad for getting smooth frequency response. Compared to larger subs 8" subs will also have limited Xmax due to the fact that you can only fit so big of a spider on them. I'll say it again, there is no reason to run 8" subs if you can fit something larger.
4. If you are after smoother frequency response there are several ways to accomplish that goal.
- Run larger subs, larger subs GENERALLY have lower motor force to cone area ratios, makes it easier to get smoother frequency response. I'd take one 15" over two 12"s or three 10"s almost every single time.
- Make the ported box smaller. Smaller ported boxes boost the low end less, making it much less likely you will end up with peaky response.
- Run sealed. With a sealed box you don't get any low frequency boost. The low end roll off of a proper sealed box closely matches the cabin gain you get in most vehicles, giving you pretty flat frequency response.
- Do like strangeduck suggested and run a ported box and EQ it flat. This is the mostly complex option, but its also the most flexible. You can get whatever frequency response you want and you can change it around really easily. Just keep in mind its easy to turn down peaks with EQ, its almost impossible to fix dips in output though. DSP/EQ is pretty cheap these days, you can get a miniDSP for a little over $100. This is what I'm doing in my own vehicle.
If I were in your shoes I'd probably try to cram two 12"s subs in a ported box if at all possible (what's the max dimensions of your space?), if its not go for two 10"s. I'd be picky about what subs I used and I'd probably use EQ to dial in exactly how it wanted them to sound.
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Hey guys,
So, I see the term pro software has a lot of features that are very important and necessary for shops and installers. However, I am looking for a good software but not as expensive as the term pro. I am trying to build a better box than the currently one I have and I don't see how I can justify $250 in the design software when I am only going to use once or twice.
Can anyone point me in the right direction please? thank you.
Get WinISD, its free, you can get it here: http://www.linearteam.org/download/winisd-07x.exe
For box layout you can use SketchUp, its also free.
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I have an E12v2 that I have been very happy with. My build is more SQ focused but I'm using mine in a 1.5 cu ft box tuned to 28 Hz on about 600 watts of power. Works great.
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I haven't had the issue yesterday or today yet, so maybe its resolved. Time will tell. I'll post back in here if it happens again.
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So I've been having this ongoing issue where I can't reply to posts or PMs. I'll type out my reply but when I click the "Post" button I get the little status bar at the top of the screen, but nothing ever happens. After a minute or so the status bar goes away and its like I never clicked "Post" at all. I would say I have this problem at least 50% of the time I try to reply to something. Its SUPER frustrating.
The really odd thing about this problem is it only happens on my desktop computer. On my laptop (or phone) I NEVER have the issue. I mostly use Chrome on my desktop, but I've tried IE and I have the same issue. I've tried clearing all my cookies for stevemeadedesigns.com but it made no difference. I thought it might be some weird DNS caching issue so I tried clearing my DNS cache/rebooting, didn't help either. At this point I'm at a loss, it been going on for quite some time (over a month) and everytime it happens I want to stab something.
Does anyone have any idea what my issue might be? Has anyone experienced this before?
Ironically when I first tried to post this thread it failed. im having to post this from my phone.
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4th Order
in Sundown Audio - GREAT Amps/Subs! GREAT Customer Service!
Posted
A parallel-tuned 6th order has both chambers firing to outside the box, a series-tuned 6th order has one chamber firing its port into the other chamber and then that second chamber fires to outside the box.