Blog Forums DIY Speakers and Subwoofers I need an order of operations. Reply To: RE: I need an order of operations.


@opulentone – Sorry for the delay getting back to you.

So, the help document for winISD first says the following:

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.”

Second is the question of what method you used for generating the MMS data in DATS. Did you do the added mass method? A known box volume? etc. This is needed for more accurate measurement of certain values.

Also, some drivers are made for open baffle, which those will show you need something infinitely large. Can you say what driver you have? Could you also give the values you have for T/S values? That way I, or others, can simulate it and we can compare what we come up with.

I don’t use discord anymore due to their terms of service and record retention policies. Sorry. I use that exclusively for old friends (and even that is limited these days).

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