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Enclosure design programs

16K views 210 replies 8 participants last post by  HumbleDeer 
#1 · (Edited)
Subwoofer design for me + discussion. [Formerly "Enclosure design programs"]

Hello,

I'm quite new here to this forum so let me first of all tell you who I am. It'll help you understand why I'm asking this.
I'm Anna, a 15 year old girl from Belgium (Nut friggin' French aight). I have built a T-Line subwoofer before with someone else's instructions and it seems to work alright. However, as I'm more and more getting into the HiFi Scene I'm noticing how my sub-woofer's SPL output at 25Hz isn't incredibly audible anymore with Treble playing over it. Maybe that's because it's a T-line, or because it's an 8 inch driver.

I've got my eye on the Dayton Audio Reference RSS315HO-44 DVC 12-inch driver. It seems like it has a quite nice xmax rating. I like big excursion woofers. Link to Specsheet


I'm hoping someone could help me find a program that's free-ware to help me design either a very good ported box, or preferably again a T-Line enclosure. Perhaps a person on here that would be kind & willing enough to help me with that over the Internet. I dont have a budget for anything paid (I'm 15. I can't have either paypal/creditcards nor a job.)

Space isn't an issue as long as it's not FrigginHjuudge (Like trump's hands >: ).) I've got an old car amplifier to power it that I scored from the dump and got back up and running after replacing a dead Op-amp and a couple caps. I have an 83Amp @ 12.3v power supply, so that's not the problem either.


If there's anything I did here against the rules, please tell me what needs changing. If you need me to tell more, or would like so, Please do so also. Thanks in advance
 
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#3 ·
I can help you simulate anything you like.

If you want to give it a shot on your own here are some good free simulators. Each has different strengths and weaknesses.

Hornresp - http://hornresp.net/
TL.app - http://leonardaudio.co.uk/
Akabak - http://www.randteam.de/AkAbak/Index.html

I also use MJK's worksheets which are arguably the best tool for tl design but I don't think they are available anymore and even if they were it isn't free.

Most of the popular software that people use around here can't simulate transmission lines, so WinISD, Unibox, etc won't work for you.

If you want design help you need to provide a list of goals - desired passband, size, stuff like that. Sims only take a few minutes so it's no problem to help.
 
#6 ·
I would need to have 'desired passband, size, stuff like that.' explained for me haha.

If I have it simulated, and I have never designed a cab myself before, How do I actually draw out how the slot port will go?

it doesn't HAVE to be a Tline. As long as it's a good ported box with a slot port. Although I would rather have a Tline over a simple ported. Tlines are also ported boxes haha.
 
#4 · (Edited)
Ehm I dont think you understand what I really mean. I'm looking for a program or programs, freeware, that help me.guide me through designing a box for this subwoofer with a slot port. Preferably a T-Line for it's fantastic characteristics. I dont need a big output, and since It's a 150 dollar subwoofer, I can afford 18mm MDF up to around 50 bucks. I have some spares laying around from my other box too. I also don't have a huge amount of work equipment. If I need wood cut, I let it be done at the store. I have a batterypowered drill which I used for drilling holes and screwing it in.

i got confused 'bout that description link btw. Don't mind all of the above :p
 
#5 ·
Ehm I dont think you understand what I really mean. I'm looking for a program or programs, freeware, that help me.guide me through designing a box for this subwoofer with a slot port. Preferably a T-Line for it's fantastic characteristics. I dont need a big output, and since It's a 150 dollar subwoofer, I can afford 18mm MDF up to around 50 bucks. I have some spares laying around from my other box too. I also don't have a huge amount of work equipment. If I need wood cut, I let it be done at the store. I have a batterypowered drill which I used for drilling holes and screwing it in.
That was meant at wldkrd1 By the way.
 
#8 ·
I appreciate your help haha.

I would like to keep my dimensions around a volume of 1x1x1m. Is that too small for a good SPL output with A T-Line? I can't do too much of angular cuts either (unless it's 45 cornerpieces, I can do those at the tablesaw at school.)

I've downloaded the Leonard Audio T-Line program, besides. It's also installed.
 
#9 ·
I want to add to that that the maximum output of my amplifier is around 150 watts clean. I know how to set the gain to be able to max out my preamp (within margin. Like 80% of the dial). My Preamp is a Schiit device. I dont remember it's name but it's the passive preamp.With a splitter at the out.
 
#10 ·
1 cubic meter is actually pretty huge, it probably won't need to be that big. The cube shape is a bit odd though, it would be a lot easier if you could make it more rectangular than cube shaped.

And it's pretty essential to set a goal for how low you want it to go before you start. Or at least figure that out as you go while considering the compromises of tuning vs max spl.

If there's a particular type of tl you would like to try I can sim something up for you tonight.
 
#11 · (Edited)
It doesn't have to be a cube haha that was just for the cubic meter. It can be 1.5m tall too, half a meter deep, and like 80cm wide. I would like to have to port on the front where I can see the sub. Those are just dimensions to example that By-The-Way

if you're making examples too will they be like.. tuned to the subwoofer? I'd like it to at least hit a nice 25Hz. I would watch movies but also music listening is a thing. I don't have a budget for things like an SVS PB2000 etc. My subwoofer is crossed over at 80Hz, besides.

Would you mind explaining what is actually the most viable in lame-girls'-language? I dont know much at all about those fancypants terms.

I tried in BassBoxPro6 yesterday too but I was disappointed it doesnt do slot ports.

Edit: I'm afraid of simple ported cabs because i've heard of some pretty bad things in terms of bass response and inability to have a flat curve.

Edit2: I love how my tline now works, even though it's probably nbot designed for this 8inch. It's actually just a stock Logitech subwoofer that I got a new enclosure for. I'm quite impressed with it. It should at least prform this well, the new one, just a little more stable in frequency? I notice a drop out in frequency around 40hz because it's not stuffed and I dont have cornerpieces in the sub.

yet another update: If I happen to postpone the purchase of the woofer would it be good enough to pick a next gen Dayton with specs as close to this one? :p
 
#15 · (Edited)
Just a quick add-on. Does it matter much that I'd rather have a wide and deep subwoofer (with the port and woofer closer to each other) than a really tall (like a skyscraper) cab?

This video from a fantastic fella called Barevids made me understand ported boxes better.

besides that, but important, I have autism. My learning capabilities are quite limited if you try to teach me the way you were taught :p

he says this about the port: From small to large is loud, from large to small is SQ. I want it inbetween the two so the straight one is fine right? :)
 
#18 · (Edited)
Just a quick add-on. Does it matter much that I'd rather have a wide and deep subwoofer (with the port and woofer closer to each other) than a really tall (like a skyscraper) cab?
You can fold the box up any way you like. It's probably going to have one short dimension - one side will probably be between 12 - 24 inches wide (30 - 60 cm) but the other two sides can be whatever you want.

This video from a fantastic fella called Barevids made me understand ported boxes better.
That's a good try but he doesn't really understand the topic very well. I'm going to get you some better information.

besides that, but important, I have autism. My learning capabilities are quite limited if you try to teach me the way you were taught :p
I don't think this will be a problem, if you don't understand what I'm saying let me know and I'll try again.

he says this about the port: From small to large is loud, from large to small is SQ. I want it inbetween the two so the straight one is fine right? :)
Well, there's a lot more to it than that but I'll show you.

For now, take a look at this paper, this is the definitive paper for transmission line design for beginners. http://www.quarter-wave.com/TLs/Alignment_Tables.pdf

This paper is an introduction that shows you how size, shape, stuffing, driver t/s parameters and other things affect the design. You can skip the entire first half (unless you love math) and just start reading where the text and graphs start. This is a fantastic paper and a great starting point for tl design. But if reading papers is not an efficient way for you to learn, don't worry, I'm going to make this easy to understand.

Later on I'll some you some sims of different enclosure types, a bunch of different transmission lines, a ported box and maybe even some horns so you can see how they compare.
 
#16 ·
Hornresp as already mentioned really is the program for you. here's a thread that shows you how to use it. http://www.hometheatershack.com/forums/diy-subwoofers-general-discussion/36532-hornresp-dum-hmm-everyone.html
You should probably go for a front-loaded horn with off-set driver (OD). You'll see what that means in the thread.
Its easier to build if you make it long in one dimension however, like this:

But if you're fixing amps and building horns at 15 you'll figure out how to fold a hold into a 11-dimensional cube if you give it a few hours.

PS: I bet the saw at school can do all the degrees, haven't seen one yet that does not. Maybe the teacher don't know how to set it for other than min/max degrees, which may happen to be 90 and 45 degrees.
 
#17 · (Edited)
I dont understand what you mean by building horn speakers? Also, I dont think that the picture you showed there is something really for me? :L I dont think I need a horn. If I'm wrong, correct me with why I would need one then? :confused:

EDIT: I can't run AkAbak By-the-way. I'm on 64bit Win10 which doesn't have a 32bit emulator that runs 16bit programs.
 
#20 ·
To start out I am going to strongly recommend learning to use Hornresp. It isn't the best tool for everything but it is very good at most things. It can sim all of the enclosure types you may be interested in, so to start out I'll introduce Hornresp and show a few of the enclosure types.

The Hornresp input screen is pretty simple once you get used to it. This pic should help. Don't worry now about the boxes I haven't circled. You can see the info I've put in the boxes so you can copy it and use it to get started playing with this simulator.

 
#21 ·
Moving right along, this is a sealed box sim using the inputs from above. You didn't ask about sealed but this is an opportunity to see how sealed boxes behave so you can compare against the other box types.

All sims are going to be shown at 150 watts since that's the amount of power you have.

This sealed box is 28.3 liters (1 cubic foot), which gives a qtc of .52, which is near critically damped. Qtc describes the low knee and roll off behavior of a sealed box as well as stored energy.

I encourage you to recreate these sims on your own and play with the size (and shape, where applicable) of the box. It's great experience. See how changes affect the different graphs. Also check on the impedance graph. The sealed box will have a single impedance peak.

 
#22 ·
Next up is a simple ported box, I filled in Ap and Lpt with the port dimension information. The sim doesn't care if the port is round or a slot port, you can build it however you like (although the sim will be accurate if the port end is not very near a wall inside the box).

This time I used the loudspeaker wizard instead of hitting "calculate". This allows access to the sliders which make changes very quick and easy.

This ported box is a bit larger than the sealed box and the low knee is around 25 hz as you requested. Making the box larger will make more spl at the tuning frequency but you don't want it to be too strong at tuning or it might sound boomy in your room. The response is very nice and flat(ish) from 25 hz up to well past 80 hz.

As shown, the design has a 3 inch round port (or equivalent slot port). The 3 inch port is a bit small and results in port air velocity of 40 meters per second which is a bit high and could cause chuffing and spl losses around the tuning frequency. It's easy to make the port larger, but then it also has to be longer to achieve the same tuning frequency.

Below tuning the driver excursion skyrockets because the enclosure is no longer providing any acoustic resistance and no load. This is bad unless controlled. This is usually done with a high pass filter on the amp. Most car audio amps have a built in high pass filter, some even have an additional adjustable high pass filter so you should be ok but it's best to research your amp and find out the details of the high pass filter to make sure your driver is going to be adequately protected below tuning.

As you can see the ported box gives a lot more output at lower frequencies compared to the sealed box. This probably isn't news to you.

This design is only using up 5 mm of the driver's excursion (assuming you have a high pass filter to protect the driver below tuning) so you could tune a lot lower or apply a lot more power if you wanted to.

 
#23 ·
This gives you a start with the basics, introduces you to Hornresp, shows you what to look for in the graphs and gives a quick comparison to sealed vs ported. You can use these sims as a starting point to do some sealed and ported sims on your own if you want to experiment with the basics.

I could continue and show examples of a few different tl styles and some horns if you like. But for now I'm going to wait for some feedback from you. If you have questions let me know. If this is not a good way for you to learn, let me know. if you want me to continue showing you sims of other enclosure types let me know.
 
#27 ·
It's a bit on the more technical/difficult size but I'm sure if I do some research about all the vocabulary you used, I'll u nderstand better. :) Thanks! Even though I understand nothing of what all the things mùean in the Hornresp GUI anywhere, and even though I dont even know if I'd need stuffing or what stuffing does or how many you need... I'll do my best :)
 
#33 ·
I don't need to see your face or anything at all on your end but I thought it would be helpful if you could see my screen.

But I have done telephone tech support too so I'm used to helping other people without being able to see what they are doing.

If you think this will help I'm willing to try it.

It's also easy enough for me to do this with just normal typing. There's only a few boxes you need to change the inputs for. After the initial inputs you just have to play with the sliders in the loudspeaker wizard and pay attention to the different graphs and how they change.
 
#34 ·
I've accidentally clicked on electrical impedance and noticed that the lower it goes, and where a ported box loses control of the driver, the electrical impedance is almost nihil. I suppose, since I have a background in electricity too, this is why speakers blow so easy down low? Low impedance means more amps over the potential difference (voltage).

Also a little offtopic. Is it normal for my woofer right now to smell a tiny bit like enamel when i sniff the dustcap (inverted dustcap)? It smells like this all the time regardless of input power (and I've never exceeded 100watts because I'm always scared of blowing my **** up).
 
#36 ·
Go to the acoustical power screen (window - acoustical power) and then go to tools - driver power. That will give you a screen to show you how much power is being used vs frequency. There are mathematical relationships between all these different graphs, the formulas are in the simulator's programming. If you want to know the formulas, David McBean (the author of Hornresp) will probably tell you if you ask him. He's got an ongoing Hornresp thread at diyaudio.com.

Below tuning you are more likely to destroy a driver by exceeding it's mechanical moving limits rather than by thermal stress.

If your driver always smells the same it's probably fine. If it smells more when it's playing loud that's not good.
 
#35 ·
How about I just record a video of my screen? It won't be interactive but you will be able to see and hear what I'm doing. And other people could benefit from that too.

I've never done an instruction video before but it can't be that hard, right? Would that help?

Not sure how I would share it though, it would be too big to attach to a forum and probably to big to email. I've never done youtube.
 
#38 ·
Well... that looks complicated. Fantastic quality though.

I played with a couple of screen capture programs a couple of years ago, I think CamStudio was one. IIRC they were pretty simple - download, install, hit record. But I didn't get picture quality that good.

Anyway, it seems that I don't have a mic installed. Maybe I deleted the drivers when I wiped out the webcam. So let me see if I can get a working mic and then I'll see if I can make a video. Hopefully it won't be too big in filesize. I've never tried uploading to youtube.
 
#44 ·
I wasn't feeling well so I didn't do anything yesterday. But today I downloaded OBS and set it up. Your video didn't help much because my OBS is very different than yours, the settings are all completely different. But it's fairly intuitive and I got it working. I was able to make a short video confirming that it is capturing my screen and voice and the video plays back just fine on windows media player. I didn't really change any video encoding settings, I left the video bitrate at 2500, changed the file type to mp4 and that's about it. Other than changing the file type I left everything default.

This software appears to be pretty good, it doesn't require you to download 3rd party crap (at least I didn't notice any), it doesn't seem to be resource intensive so there's no lag or jittering. This was a big problem with other screen capture programs I tried a few years ago, even when I only recorded a 800 x 640 portion of the screen there was terrible lag and the mouse would jump around because the computer couldn't keep up.

So I'll probably have a video for you tonight or tomorrow. The first one will be very basic, just the fundamentals and just for you to get you started. But if there is enough interest maybe I'll make a much more comprehensive video for the general public. I was planning to do this years ago but it never fell into place. For a more formal video I'll need to have basic editting functionality, not sure if OBS has that, but I can probably get it done with Windows Movie Maker or something like that. I won't be able to do a full comprehensive video in one take.
 
#45 · (Edited)
In mean time I've gone over your guide again, researched some stuff, and looked into buying the new mouse I wanted. next on my list is €250 for the driver I'll be buying :).

Obs is a simple and open source streaming program that happens to fall into the grooves of recording too. I use VSDC movie editor for free stuff, and I have Sony Vegas Pro too.
 
#48 ·
This sunday there's a show on the central place of our little town. With those extremely modified cars just to fit like a 12 inch car subwoofer. Honestly, I dont know what's so special about them. I've found most of them to sound horribly loud, and that's mostly to cover up any of the rattling :p
 
#49 ·
Ok, well ...

I started recording today and this is a bit different than I thought. My first take ended up 2 hours long and the filesize of the video was over 2 Gb. The first take covered about half of what I want to get through, so there's still a lot more to do.

Not sure what to do about this - not sure anyone wants to watch a 4 hour Hornresp movie and I'm not sure where I would host a file like that.

Maybe I'll have to re-evaluate.

This was just a stream of consciousness run through, not scripted. Not sure if I should cut most of this stuff out or cut it into several small videos or make it a lot more basic. Not sure of anything at this point.
 
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