purchase lspcad or new excel for unibox?

Discussion in 'Archived Threads 2001-2004' started by Brad Dixon, Jun 25, 2002.

  1. Brad Dixon

    Brad Dixon Stunt Coordinator

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    I'd like to know if anyone would give their input on this.

    I'm enjoying running the sims as best I can but at the moment my computer just does not want to work with unibox and excel 97. Half the time when I make a change it gives the "illegal operation" and closes unibox.

    Since lspcad is ~125 I was actually thinking of buying it instead of a newer version of excel(to hopefully use unibox 3.1), since 97 does everything I need except unibox and it costs more.

    So, I guess my question is.... Given that I'm going to have to spend some money on a program is there a reason you'd pick one over the other?

    I've only used adires version of lspcad but it seems to have more features than I need/use at the moment. I haven't really been able to use unibox as it gets a little frustrating after entering the T/S parameters in(sometimes I can model a box partially) it gives an error and closes.

    Thanks for any thoughts,
    Brad
     
  2. Janne Ahonen

    Janne Ahonen Extra

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  3. Brad Dixon

    Brad Dixon Stunt Coordinator

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    Janne,
    Well I had searched the forums and it seemed as though lspcad and unibox were more often recommended. The rason I beleive was that they were more accurate. I'd have to go back thru and double check but I don't recall any bad things about winisd just the others were more often used/recommended was all.

    I'll d/l it tonight and give it a shot. I saw it a couple nights ago but felt I better not since it was in alpha stage.

    What I do like about unibox (even though I haven't really been able to use it) is that it looks like you can model different boxes without having to have multiple sessions open.

    Thanks,
    Brad
     
  4. Janne Ahonen

    Janne Ahonen Extra

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    Hi Brad,
    I believe comments you read were referring to older version, I think that we have made quite a improvement over that.. It seems that many people haven't even tried the pro version.
    Again, even if it is called alpha, there shouldn't be any serious major bugs, at least we haven't heard about them..
    If it makes you more confident about the program, you can read Adire's Brahma 15 manual, it recommends using WinISD pro over the old version [​IMG] So I think it is not very bug-ridden.. One thing I perhaps should mention, WinISD pro shows peak-to-peak cone excursion, as does LspCAD. Remember it when wondering about the results.
    Btw, you can simulate multiple designs at same time with WinISD pro, just open multiple projects. It can even simulate multiple boxes of same types (which can't be done using Unibox) with same or different drivers. With Unibox you can only use same driver in different boxes.
    Regards,
    Janne
     
  5. Isaac C

    Isaac C Stunt Coordinator

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    Brad,
    Both winISD Pro and Subwoofer Simulator are based on electroacoustics and I think, don't quote mo on this, Unibox is based on electroacoustics or equivalent circuits as well. So accuracy over the other is irrelevant, I think. Offered features is what counts, I would say.
    Without the annoying Excel errors IMO Unibox is great for displaying the impulse response of your design. But I would not recommend buying the latest Excel version just for that.
    Aside from what Janne has mentioned, winISD Pro has a user-friendly user-interface. SubSim, on the other hand, well it's a different approach as Janne mentioned [​IMG] SubSim will let you simulate all the supported boxes at the same time, but not multiple instances of the same box type; at least not yet. What's neat with SubSim is that you can feed it acoustic measurements of your listening room and use it to display your design's in-room response. Moreover, SubSim uses only one graph space to display any or all of the curves. This is especially educational for beginners as one can conveniently see the relationship between each curve type.
    Unfortunately, I'm still a college student, so spare time for developing SubSim and xoversim is rather limited. But the following features will be added soon [within weeks, if not a few months].
    1. 10-band equalizer -- this one is now in software form
    2. up to 8th-order LP/HP active filter -- Sallen-Key-based for circuit simplicity. The equations and ideas are written on pieces of paper here somewhere [​IMG]
    3. Box optimiser -- also working and in software form. 6th/8th order box optimiser code is a bit slow, so that needs more work.
    I just need to change SubSim's code to ease the pain [​IMG] in integrating the above-mentioned features and other planned features for that matter [​IMG]
    Everything you'd need is already out there.
    For boxes:
    winISD Pro
    Unibox
    Subwoofer Simulator
    As well as Baffle Diffraction Simulator and other great tools from the FRD Group
    Speaker Workshop is good for T/S extraction as well as crossover simulation.
     
  6. Isaac C

    Isaac C Stunt Coordinator

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    JohnQ,
    Subwoofer Simulator will calculate the new curves as soon as you press the Enter key. Clicking anywhere outside the silver border of the graph space will refresh the screen as well [​IMG]
    I have also made SubSim to (try to) reject bogus or impossible numbers. For example, if the desired Qtc is less than the driver's Qts, which is impossible given just a driver and a sealed box, SubSim will output a very large Vb = 1e12 or simply freeair.
    Just in case, the last self-extracting SubSim version I had uploaded came with subfolders and several driver files. This helps organize input/output files. There were micro changes in the code too if I can recall [​IMG]
    hth, please let me know if the problem persists.
    Isaac
     
  7. Isaac..is there anyway that in your next revision you can somehow incorperate any non linearities?...or how about inductance?
     
  8. Isaac C

    Isaac C Stunt Coordinator

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    Anthony,
    I've already added voice-coil inductance simulation. Here's a screenshot with imp. phase and in-room response [​IMG]
    [​IMG]
    Non-linearities will have to come later on, I haven't read much about the subject really [​IMG]
    Isaac
     
  9. Thanks Isaac. I haven't really played with the simulator much, but looks like I probably should give it a try. Do you incorperate different stuffing parameters like on unibox? (again, I haven't tried yet)

    if you can get the non-linearities, then you will be really set!

    perhaps incorperating a LT into the sims would be nice=)
     
  10. Isaac C

    Isaac C Stunt Coordinator

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    The effects of enclosure filling is approximated by Qa.
    //----------
    Taken from the Adire Audio version of LspCAD:
    QA that is the Q-value due to damping materials in the box. The range of QA is 3-100. A box with moderate lining has a QA of about 30. A heavily stuffed box can have a QA of
    3.
    If the box is completely stuffed with damping material, the QA will decrease, but also will the virtual box volume increase with about 20% i.e. the driver unit will experience a larger box than Vb.
    Stuffing -- Qa:
    100% -- 3
    50% -- 7
    0% -- 15-30
    //----------
     
  11. awesome! thanks
    I just like how unibox had the moron proof drop boxes. ..but now that I know what to change, I can pretend to not be a moron[​IMG]
     
  12. Janne Ahonen

    Janne Ahonen Extra

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    Hi Anthony,
    I just wanted to know have you tried WinISD pro?
    What Isaac said of stuffing (Qa and box volume) applies also on WinISD pro, enclosure quality factors are found under "advanced ->" button. Another features we added during last release 0.50a6, is the calculation of maximum SPL with Xmax and Pe restrictions, and printing of graphs. I believe that is one goodie of WinISD pro.
    Because all programs are based on same (probably) electroacoustic models, results should agree, but there is one degree of freedom, air properties can be different (main reason why various programs give you different port lengths with same inputs). Also, modelling leaks in closed box makes some difficulties, because it turns nice second order system into third order one (this is predicted also by Mr. J. E. Benson, another famous Australian [​IMG] ), although effect is not severe, that extra transfer function pole is virtually on origin of s-plane, using typical losses. But, Qtc is not then well-defined. Even voice coil inductance is not quite a real inductance, but something more like "semi-inductive".
    Indeed, seeing some graphs simultaneously is beneficial. We have thought much how it would be possible to clearly show multiple graph types at same time with many different designs open, but we haven't come up with decent solution to that problem. Possibility to compare two different drivers at same time is beneficial, I think.
    I must say that we (Me and Juha as authors of WinISD pro) have thought about adding simulation of any user-specified transfer function, that way it doesn't impose restrictions on actual filter implementation, whether it is Sallen-Key or state-variable or other realization. But, nice user interface needs to be developed.
    Developing these things have been kinda slow, because both Juha and I have full-day jobs..
    Just my two cents on the subject.
    Regards,
    Janne
     
  13. Dan Wesnor

    Dan Wesnor Second Unit

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    I have LspCAD and I still use Unibox for box design.
     

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