Best tool for calc'ing ports for Active speakers??

[dzach]

Kind of a dumb question here...

I am trying to determine the port #/size/length for an active sub for the home (single Dayton RS HF 10", 500w Bash, 2.3 ft3 box).

What is the best tool for doing this?
I have used WinISD, but this does not ask for the plate amp power...
Should this be a consideration?
Which tool would you recommend?

Thanks!!
dzach

[Jeff B.]

> Kind of a dumb question here...

> I am trying to determine the port
> #/size/length for an active sub for the home
> (single Dayton RS HF 10", 500w Bash,
> 2.3 ft3 box).

> What is the best tool for doing this?
> I have used WinISD, but this does not ask
> for the plate amp power...
> Should this be a consideration?
> Which tool would you recommend?

> Thanks!!
> dzach

Well, if you have Excel then this tool was designed for exactly this purpose:

<A HREF="http://www.pvconsultants.com/audio/eq/boxcircuit.htm">http://www.pvconsultants.com/audio/eq/boxcircuit.htm</A>

[Paul O]

The ports in a speaker enclosure have NOTHING to do with the power amp connected to that speaker, be it active or passive. They are calculated using the drivers power handling.

[dzach]

Thanks Paul, that was the exact answer I was looking for.

And thank you Jeff for the Excel tool. I am going to check it out right now.

dzach

> Kind of a dumb question here...

> I am trying to determine the port
> #/size/length for an active sub for the home
> (single Dayton RS HF 10", 500w Bash,
> 2.3 ft3 box).

> What is the best tool for doing this?
> I have used WinISD, but this does not ask
> for the plate amp power...
> Should this be a consideration?
> Which tool would you recommend?

> Thanks!!
> dzach

[Jeff B.]

> The ports in a speaker enclosure have
> NOTHING to do with the power amp connected
> to that speaker, be it active or passive.
> They are calculated using the drivers power
> handling.

I was only sending him to a tool that allowed for proper box tuning when using active circuitry like you find with most sub amps. These systems really should be viewed from a system level of all things considered.

[paul_n_oneal]

That's what I thought he meant too. The Unibox Excel program lets you import the amp response so that you can better tune the box. I've played with it a few times and it works well.

[Paul O]

I wasn't replying to Jeff actually but the OP.
That is a nice tool, BTW... gives a pretty straight forward output of the system capabilities. The driver is still ultimately the limiting factor... that's the point I was making.

[unknownuser]

What does it take to get this to work? I installed it, and it shows all of the fields, data and graphs, but no information on the graphs.

Frank

> Well, if you have Excel then this tool was
> designed for exactly this purpose:

>
> <A HREF="http://www.pvconsultants.com/audio/eq/boxcircuit.htm">http://www.pvconsultants.com/audio/eq/boxcircuit.htm</A>



(Originally posted by: Frank)

[Jeff B.]

> That's what I thought he meant too. The
> Unibox Excel program lets you import the amp
> response so that you can better tune the
> box. I've played with it a few times and it
> works well.

I don't want to knock Kristian because Unibox is a great tool, but I believe it handles imported amp responses incorrectly, and Kristian and I have discussed this. Unibox normalizes the response to the maximum gain of the circuit. So if you have +6 db of EQ then your overall response is lowered 6 db from what you really have, this means that excusion, sensitivity and power graphs are now all off by 6 dB or a four-fold drop in power.

This is part of the reason I built the Woofer and Box Designer I linked above. I included the transfer function of what ever circuitry you have and displays its effects on driver response, excursion, etc. accurately.

Unibox is a more complex box model, but again, I don't think it handles EQ correctly.

Jeff B.

[Jeff B.]

> What does it take to get this to work? I
> installed it, and it shows all of the
> fields, data and graphs, but no information
> on the graphs.

> Frank

If you check all of these items and it still doesn't work, let me know, but 99% of the time your problem will be one of these things:

1.) Make sure your security in Excel is no higher than medium so that it prompts you regarding macros.

2.) When prompted you must say yes to macros

3.) In Excel go to Tools; Add-ins and make sure "Analysis Toolpak" and Analysis Toolpak- VBA" are both checked.

It is usually one of these things that keeps the spreadsheet from running for most people. More often than not it is the Toolpaks not being loaded in that is the culprit.

Jeff B.

[unknownuser]

(Originally posted by: DDF)

[unknownuser]

:) It was the Analysis Toolpaks. Thanks!

> If you check all of these items and it still
> doesn't work, let me know, but 99% of the
> time your problem will be one of these
> things:

> 1.) Make sure your security in Excel is no
> higher than medium so that it prompts you
> regarding macros.

> 2.) When prompted you must say yes to macros

> 3.) In Excel go to Tools; Add-ins and make
> sure "Analysis Toolpak" and
> Analysis Toolpak- VBA" are both
> checked.

> It is usually one of these things that keeps
> the spreadsheet from running for most
> people. More often than not it is the
> Toolpaks not being loaded in that is the
> culprit.

> Jeff B.



(Originally posted by: Frank)

[Jeff B.]

[Dirk]

> Thanks Paul, that was the exact answer I was
> looking for.

> And thank you Jeff for the Excel tool. I am
> going to check it out right now.

> dzach

I'm a big fan of Unibox, but WinISD Pro Alpha can also show you power response. It can also apply variable Q filters (a la plate amp) to the signal. Just be warned that if you simulate 100W with a +6db boost at 30hz, it's actually showing you the excursion for 400W applied at 30hz, so you have to simulate 25W applied power if you actually wanted to know what a 30hz sine wave @ 100W would do to your driver.