I've been trying to use Win ISD to design some sealed cabinet speakers using the Peerless/Tympany SDS-830656. QMS - 3.6 QTS - 0.59 QES - 0.7 FS - 57 Hz. Win ISD chokes when I try to enter these parameters into the speaker database, saying, in effect, "I don't believe you". Any way to fix this?
Interesting - I'll try again tonight with that in mind - thanks.
I plan to load 16 of these drivers per side in a hexagonal prism cabinet of proper volume, using some 3" Fountek drivers in sealed chambers to cover the high end.This will be similar to a design I did back in the late 70's, but with suitable cabinet volume and drivers actually suited for the job...
I plan to load 16 of these drivers per side in a hexagonal prism cabinet of proper volume, using some 3" Fountek drivers in sealed chambers to cover the high end.This will be similar to a design I did back in the late 70's, but with suitable cabinet volume and drivers actually suited for the job...
Basicly inaccurate spec sheets and rounding errors. And winISD is rather picky on right specs. Best is to give some and let the rest be calculated by the program itself. Or measure your speakers (if done right, it should work).
It seems to be picky about what order you put in the values; Left to right, and then the next line works. You can use the 'Tab' key to go to the next parameter.
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I have this as a text file (think I copy / pasted from winISD help)
The suggested procedure for entering driver parameters is following (check first that "Auto calculate unknowns" option is checked):
1. Enter Mms and Cms
This gives fs. If either is not available, then enter fs and other parameter.
2. Enter Sd, Bl and Re
Now, you should get all but Qms (and Qts), Vas. Please note that Vas may not match exactly what is specified by manufacturer, because exact value of Vas depends on environmental parameters. See FAQ.
3. Enter Rms or Qms.
Either one will do, although I tend to prefer Qms over Rms, because it can usually be measured in driver measurement procedures.
4. Enter Hc, Hg and Pe.
If Hc or Hg or either is available, then enter Xmax and optionally either Hc or Hg if available.
5. Enter number of voicecoils.
This procedure is most accurate. Also note that it also calculates true SPL (1W/1m) value. So it might not match the marketing SPL value, which is generally somewhat vague. Not in all cases, though.
6. Correct Znom, if necessary.
If there are several voicecoils, then you must be careful when entering parameters in that case, because many manufacturers give Bl in voice coils in series, because it yields double value for Bl against parallel connection. If driver manufacturer gives Qes, Bl and Cms or Mms, then you can check how Bl is specified. For that, you can enter following parameters to calculate Re: Qes, Fs, Mms or Cms and Bl. Connection mode can be changed by changing the combobox selection. The driver editor then converts Bl and Re values accordingly.
Equivalently, you can check for Bl by entering:
Qes, Fs, Mms or Cms and Re (for desired connection mode).
If you enter resistance for parallel connection and get about half of advertised Bl, then you know, that Bl was specified that way.
Like in Driver-tab in project window, you'll probably noticed the driver icon in bottom of the driver editor window. you can drag the driver object into some project by just dragging the icon.
The suggested procedure for entering driver parameters is following (check first that "Auto calculate unknowns" option is checked):
1. Enter Mms and Cms
This gives fs. If either is not available, then enter fs and other parameter.
2. Enter Sd, Bl and Re
Now, you should get all but Qms (and Qts), Vas. Please note that Vas may not match exactly what is specified by manufacturer, because exact value of Vas depends on environmental parameters. See FAQ.
3. Enter Rms or Qms.
Either one will do, although I tend to prefer Qms over Rms, because it can usually be measured in driver measurement procedures.
4. Enter Hc, Hg and Pe.
If Hc or Hg or either is available, then enter Xmax and optionally either Hc or Hg if available.
5. Enter number of voicecoils.
This procedure is most accurate. Also note that it also calculates true SPL (1W/1m) value. So it might not match the marketing SPL value, which is generally somewhat vague. Not in all cases, though.
6. Correct Znom, if necessary.
If there are several voicecoils, then you must be careful when entering parameters in that case, because many manufacturers give Bl in voice coils in series, because it yields double value for Bl against parallel connection. If driver manufacturer gives Qes, Bl and Cms or Mms, then you can check how Bl is specified. For that, you can enter following parameters to calculate Re: Qes, Fs, Mms or Cms and Bl. Connection mode can be changed by changing the combobox selection. The driver editor then converts Bl and Re values accordingly.
Equivalently, you can check for Bl by entering:
Qes, Fs, Mms or Cms and Re (for desired connection mode).
If you enter resistance for parallel connection and get about half of advertised Bl, then you know, that Bl was specified that way.
Like in Driver-tab in project window, you'll probably noticed the driver icon in bottom of the driver editor window. you can drag the driver object into some project by just dragging the icon.
There is better software which won't confuse you with stupidities. Find excel spreadsheets by Charlie Laub, Jeff Bagby and Paul Verdone on Charlie's pages.
I'm designing both the speaker I described and a companion subwoof. I'll let y'all know how it works out.
For the main speaker, I have the choice of some MCM aluminum drivers I already have on hand, though not quite optimum for a sealed enclosure. I want to see if there is any advantage to using the Peerless drivers I mentioned (with a higher QTS than the MCMs (0.59 vs. 0.4) before dropping the dosh for 32 of them.
For the main speaker, I have the choice of some MCM aluminum drivers I already have on hand, though not quite optimum for a sealed enclosure. I want to see if there is any advantage to using the Peerless drivers I mentioned (with a higher QTS than the MCMs (0.59 vs. 0.4) before dropping the dosh for 32 of them.
OK, so it's copied from it, just used the program for many years and never needed any help, only knew there was an online tutorial.
GM
Hmm, I'd be more interested in which performed better above the driver's upper mass corner [Fhm] where T/S theory peters out as sealed is very flexible and other than increasing cab size are fine up to a ~0.707 Qts' and some will say up to a ~1.4 Qts'.
Fhm = 2*Fs/Qts'
Qts' = Qts + any added series resistance [Rs]: HiFi Loudspeaker Design
GM
I'd forgotten about the expedient of using a series resistor to change the QTS. I'll look at that as soon as I get WinISD to work for the Peerless drivers.
The first thing I might try is modeling the drivers that used to be in my cabinets, which were Vifa mid-woofs with a QTS totally inappropriate for sealed cabinets (0.27). A 4 ohm series resistor brings the QTS up to 0.51 - much better. Of course, I'm blowing a lot of power that way, but it's just a modeling exercise, after all.
That qts is not a problem, only the fs of the box will be higher. But the box will work. Low qts makes the speaker go less low in a sealed box than the specs say. Model it and you will see...
Well, like everyone else, I'm trying to get as much bass extension as possible without having to build a huge monkey coffin, so I'll be looking at higher QTS in my sims. Having said that, I'll probably try a sim of the Vifa drivers as-is with my original cabinet volume to see how bad it was (probably pretty bad).