Hi all. First let me say i have never built a speaker, and this is the first time I have used winisd. I would like to build a sealed box speaker using the new SBA 8" fr driver. Downloaded winisd and came up with a 46.55 liter box. Then I went to an online modeling site and they came up with 45 liters. So far, pretty close. However, the Madisound site that sells the drivers recommends .6 to 1.0 cubic foot box. or roughly 16 to 28 liters. I have also read where stuffing the box with polyfill or whatever makes the box effectively 20 to 25% larger. So now the driver thinks its in 54 liter box???? I don't quite know what to believe here.
Never used winisd before so it is entirely possible i did something wrong, but on the other hand, the online calculator agreed pretty much on the size of the box. I understand the compromises of a sealed box vs vented but am willing to sacrifice some bass for better accuracy. I also want one the correct volume so it doesn't lose the effect of the sealed box properties.
So, did I do something wrong or is the seller wrong??? This will be a first time build, and have wanted to try an FR driver for some time now. Just want to get it as correct as possible to get the best results I can. Any input is greatly appreciated. Thanks, J.D.
Never used winisd before so it is entirely possible i did something wrong, but on the other hand, the online calculator agreed pretty much on the size of the box. I understand the compromises of a sealed box vs vented but am willing to sacrifice some bass for better accuracy. I also want one the correct volume so it doesn't lose the effect of the sealed box properties.
So, did I do something wrong or is the seller wrong??? This will be a first time build, and have wanted to try an FR driver for some time now. Just want to get it as correct as possible to get the best results I can. Any input is greatly appreciated. Thanks, J.D.
Sealed isn't necessarily 'more accurate' than vented unless some very specific definitions and caveats are made about what is meant by 'accurate', so I'd be a bit careful on that assumption as a broad principle. There's a reason vented boxes exist.
There's nothing wrong with WinISD insofar as it is what it is, and uses the same basic formulas for given box alignments as most everything else. Its default status however assumes little or no leakage, and no damping, so that's where some of the differences come into effect. You can add them by adjusting the Qa and Ql values -when they are equivalent to other software, then there should be little or no difference beyond some potentially accounting for an extra decimal place. Within a couple of percentage points it shouldn't make much difference.
Stock alignments are just that though. There is no obligation to use them. Thiele / Small parameters and the alignments mentioned (B4, QB3, BB4, SBB4 & so on & so forth for vented, Butterworth, Bessel etc. for sealed) are derived from electrical filter theory, so they tend to track existing or near equivalents from that. They're consistent for obvious reasons (providing the driver in question has characteristics that fall within their loading requirements) & for obvious reasons most on-line calculators tend to use them for speed & programming simplicity. They don't necessarily account for anything else though, such as power-handling, room position, baffle losses, acoustic preferences etc., which is why most modellers including WinISD allow you the freedom to alter volume, damping, leakage coefficients & tuning / vent loss coefficients as relevent.
There's nothing wrong with WinISD insofar as it is what it is, and uses the same basic formulas for given box alignments as most everything else. Its default status however assumes little or no leakage, and no damping, so that's where some of the differences come into effect. You can add them by adjusting the Qa and Ql values -when they are equivalent to other software, then there should be little or no difference beyond some potentially accounting for an extra decimal place. Within a couple of percentage points it shouldn't make much difference.
Stock alignments are just that though. There is no obligation to use them. Thiele / Small parameters and the alignments mentioned (B4, QB3, BB4, SBB4 & so on & so forth for vented, Butterworth, Bessel etc. for sealed) are derived from electrical filter theory, so they tend to track existing or near equivalents from that. They're consistent for obvious reasons (providing the driver in question has characteristics that fall within their loading requirements) & for obvious reasons most on-line calculators tend to use them for speed & programming simplicity. They don't necessarily account for anything else though, such as power-handling, room position, baffle losses, acoustic preferences etc., which is why most modellers including WinISD allow you the freedom to alter volume, damping, leakage coefficients & tuning / vent loss coefficients as relevent.
Thank you Scott for the education. I have seen nearly every tutorial on utube about winisd and none showed you could change or add values. I will play with it some more. Parts express has some small tower kits with about 33 liters. I may end up using those as my wood working skills are less than stellar. For the most part this will be an experiment into FR drivers and if I don't like them, I won.t have a ton of money invested.
Perhaps "accuracy" was a poor word choice. quicker might be a better word. I have several sets of speakers, vented and sealed. Ironically, my main speakers are vented. However, I have listened to the sealed right next to the vented and done a-b comparisons. The sealed didn't go as low but the bass was more articulate and faster overall then the vented. Like a rim hit on a drum, cymbals, and sound cleaner....to me ymmv.
I readily admit there are reasons why vented boxes exist. I would say the majority of commercial speakers are vented. There are many people on this forum building vented. What I don't understand, and again with an unquestionable ignorance of the subject, is how a vented box, even a simple bass reflex box, can help but have phase issues. How the sound from the driver and the sound from the vent can reach the listener at the same time. Especially in a transmission line where the the back wave has to go through a maze of various sized baffles before it exits the vent. I know they work, but don't see how it's possible. Oh well, a question for another thread maybe.
Thanks again Scott for the help. Sometimes the more I research this stuff the more confused i get. Maybe I should stick to circuits, those I understand, lol. Have a good one Scott. Input much appreciated.
Perhaps "accuracy" was a poor word choice. quicker might be a better word. I have several sets of speakers, vented and sealed. Ironically, my main speakers are vented. However, I have listened to the sealed right next to the vented and done a-b comparisons. The sealed didn't go as low but the bass was more articulate and faster overall then the vented. Like a rim hit on a drum, cymbals, and sound cleaner....to me ymmv.
I readily admit there are reasons why vented boxes exist. I would say the majority of commercial speakers are vented. There are many people on this forum building vented. What I don't understand, and again with an unquestionable ignorance of the subject, is how a vented box, even a simple bass reflex box, can help but have phase issues. How the sound from the driver and the sound from the vent can reach the listener at the same time. Especially in a transmission line where the the back wave has to go through a maze of various sized baffles before it exits the vent. I know they work, but don't see how it's possible. Oh well, a question for another thread maybe.
Thanks again Scott for the help. Sometimes the more I research this stuff the more confused i get. Maybe I should stick to circuits, those I understand, lol. Have a good one Scott. Input much appreciated.
How about a Pensil? Doesn't have to be for the Mark Audio P7HD, but here's an example. Proven design, relatively simple box to build. Lots of smaller stand mount designs as well: https://www.markaudio.com/online_shop/pluvia/pluvia-7-2-hd/
Dave's got some designs for this driver, but the Onken style boxes will require a bit more wood wooking skill. Maybe a Golden Ratio if you're ok with a smaller stand mount.
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It's straightforward enough. I've got the proAlpha on the PC at the moment (although I rarely use it). Using that as the basis, since they're all quite similar in terms of interface, select / enter whatever driver you happen to be using, the number & box type (in your case sealed), and whatever generic alignment you feel inclined to select. It will then spit that out assuming no leakage & no damping. In the pop-up box that accompanies the default graph (which is usually Transfer Function Magnitude), select the 'Box' tab, and where it says 'volume' adjust at will. The plot will automatically alter to indicate the alignment with the entered value. Lower down you'll see an 'Advanced' tab. Select, & you'll get a second pop-up box, with Ql (box leakage) and Qa (damping) coefficients. Adjust as desired. Ql is relatively representative as-is, Qa not. A well-damped box with, say, 1in acoustical fibreglass lagging will have a Qa of roughly 30. Heavily stuffed will be around 10 - 15. This isn't absolutely exact as it varies with material & density, but those are reasonable approximates.
This depends on alignment rather than box type as such. You can have chronic ringing with a sealed box if Q is too high in the desired passband for example.
Depends what you call 'issues'. They're phase inverting types, certainly (as in they reverse the phase of the rear output to match that of the front).
It doesn't, but there are audibility thresholds involved with this; human hearing acuity is poor at low frequencies. Assuming a speed of sound of about 1.14ft/msec, the audibility threshold at 500Hz has been demonstrated to be roughly 3.2msec. That just increases as frequency drops & wavelengths increase: the lower you go, the longer the wavelength & the greater the distances between independent sources needs to be before they become audible as such.
Ringing is a separate issue: a sealed box with a decently damped alignment will usually be better than a vented in this regard, though whether this is independently audible will depend rather more on circumstances than a bald graph or assumption can tell you. This is the problem -we're not dealing with these things in isolation. In themselves they may be very good, but something else may end up being more audible anyway, rendering it all a bit moot. The truth is that most vented boxes aren't very well designed. A good proportion just go with a generic maximally flat B4, QB3 etc. alignment with zero consideration for anything else, and most of those as a result will tend to cause an excess of gain if placed anywhere near a room boundary, with all the resonances, overhang etc. that go with it. A box with an alignment more carefully designed for the intended use on the other hand is a different story.
Not anywhere near up to date, but better than nothing: https://www.hometheatershack.com/th...e-on-how-to-use-winisd-pro.6330/#post-1582850
Ditto these driver files, but for folks looking for old driver specs, maybe of some use: https://www.hometheatershack.com/threads/downloadable-winisd-pro-files.14410/
Ditto these driver files, but for folks looking for old driver specs, maybe of some use: https://www.hometheatershack.com/threads/downloadable-winisd-pro-files.14410/
You could look at the two boxes like a 4th order rolloff vs a 2nd order, and forget what you had to do to get that. This may help to see only what matters.
Thanks for the effort Vinylkid, but I'm pretty much committed to a closed box. That said, if this works out to my satisfaction I haven't seen any rules where you can only build One!!
Again Scott, thank you. Very helpful and so many things I was unaware of. As you and Mr Chang state the time difference is actually irrelevant. Gives me a new perspective on vented boxes. So, as long as both signals, so to speak , are within 10ms, I can't tell the difference. Interesting. Can you recommend any books that are for rookies and cover at least some of the basics?? Thanks again Scott and Mr Chang.
GM....Thanks for the links, I will check em out.
Allenb...Thanks for your input. I think I know what you mean.
With all this information, I have come up with a plan. PE sells small tower boxes with 3 braces. Top, center and bottom. Easy enough to seal off part of the box. So on one I will put together as is, line it, stuff it and use as a baseline. The other I'll seal off the bottom section at the brace, line it, maybe not stuff it. Hook em up to an amp and tune them by ear till I like em. Maybe not the best plan in the world and certainly not very scientific, but at the end of the day should all come out in the wash. Can't thank you guys enough for the help. The boxes are currently back ordered but should release by months end. Still need to order the drivers, so It'll be a minute or two to get it all together. By then should be warm enough to play in the garage. Thanks again and best regards to all.
Again Scott, thank you. Very helpful and so many things I was unaware of. As you and Mr Chang state the time difference is actually irrelevant. Gives me a new perspective on vented boxes. So, as long as both signals, so to speak , are within 10ms, I can't tell the difference. Interesting. Can you recommend any books that are for rookies and cover at least some of the basics?? Thanks again Scott and Mr Chang.
GM....Thanks for the links, I will check em out.
Allenb...Thanks for your input. I think I know what you mean.
With all this information, I have come up with a plan. PE sells small tower boxes with 3 braces. Top, center and bottom. Easy enough to seal off part of the box. So on one I will put together as is, line it, stuff it and use as a baseline. The other I'll seal off the bottom section at the brace, line it, maybe not stuff it. Hook em up to an amp and tune them by ear till I like em. Maybe not the best plan in the world and certainly not very scientific, but at the end of the day should all come out in the wash. Can't thank you guys enough for the help. The boxes are currently back ordered but should release by months end. Still need to order the drivers, so It'll be a minute or two to get it all together. By then should be warm enough to play in the garage. Thanks again and best regards to all.
I just put my comment in here as it is about WinISD. Downloaded the newest version on a Windows 11 computer. Allt the texts are extremely small and the pop-up menus are so tiny so they are not possible to read. Multiple changes in the display setup didn´t change the problem a bit. Also several downloads diddn´t either..... Anyone come through the same probelm?
From what I understand, even if you are cornered into a new computer, a competent teenager should be able to set up a virtual machine running vanilla Windows 7 in a container/file. Then you can open that (which boots up like it's a separate computer) and install the older programs inside that OS.
I haven't messed with it because my wife's Windows machine was a pretty decent i7-multicore and has made it this far, and I only have old end-of-life Chromebooks with linux installed on them (not ideal for running a virtual machine).
I haven't messed with it because my wife's Windows machine was a pretty decent i7-multicore and has made it this far, and I only have old end-of-life Chromebooks with linux installed on them (not ideal for running a virtual machine).
Im running windows 10 and just installed the older WinIsd pro alpha. It is what im use too.
I cannot stand the newer version.
It is useful as a calculator and I like the sum check for driver parameters.
Also easy to cross calculate imperial/metric.
Far as the original question.
When you calculate sealed with Winisd it will shoot automatically for lowest feasible Q
based on driver parameters. So likely you 45 liter box was around .707 to .8 Qtc
For whatever reason Madison sound choose a higher Q enclosure which is smaller.
So WinIsd will do the same thing. you can pick whatever Qtc you want when you start the project.
Sounds like they likely recommend something in the 1 to 1.1 Qtc range.
where as Winisd and the online calculator with " Auto" align will shoot for low Q so
yes the boxes will be bigger.
as long as the driver can mechanical do lower Q or total Qts is not too high.
WinIsd can calculate down to .5 Qtc up to usually 1.5 Qtc
.5 Qtc being larger box 1.5 Qtc being very small.
you can open multiple projects in WinIsd with same driver.
Another feature I like since you can compare different alignment results all at once.
Are you talking about the
I cannot stand the newer version.
It is useful as a calculator and I like the sum check for driver parameters.
Also easy to cross calculate imperial/metric.
Far as the original question.
When you calculate sealed with Winisd it will shoot automatically for lowest feasible Q
based on driver parameters. So likely you 45 liter box was around .707 to .8 Qtc
For whatever reason Madison sound choose a higher Q enclosure which is smaller.
So WinIsd will do the same thing. you can pick whatever Qtc you want when you start the project.
Sounds like they likely recommend something in the 1 to 1.1 Qtc range.
where as Winisd and the online calculator with " Auto" align will shoot for low Q so
yes the boxes will be bigger.
as long as the driver can mechanical do lower Q or total Qts is not too high.
WinIsd can calculate down to .5 Qtc up to usually 1.5 Qtc
.5 Qtc being larger box 1.5 Qtc being very small.
you can open multiple projects in WinIsd with same driver.
Another feature I like since you can compare different alignment results all at once.
Are you talking about the
SB20FRPC30-8
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