Subwoofer design with unknown driver

miguel2 · 5th February 2004, 11:19 AM

Hi,

I have a 12" driver that I think it is from Phillips (an old one). I am using it with the Pass design El-Pipe O, with good results. But now I having trouble in puting that big ugly tower in the living room, you know why dont you

.
So I though of using the driver in a box or something like that. But the problem is that I dont have any specs. Is there any decent way to do it?

Miguel

Timn8ter · 5th February 2004, 01:14 PM

If you have a multimeter perhaps this will help.

FrankDIY · 5th February 2004, 01:19 PM

SpeakerWorkshop works great to measure speaker parameters.

miguel2 · 11th February 2004, 10:37 AM

The problem is that if I understand correctly, I must have a box to measure Vas. So I would have to build one to get that and then build another one...
Is there a way to go round this?

Miguel

Ouroboros · 11th February 2004, 11:08 AM

You can get a reasonable measure of Vas by adding a known mass to the cone and measuring the new (lower) resonant frequency.

There's a site with a spreadsheet on it to calculate the parameters using this method.

I've forgotten the URL though. I could email you the spreadsheet if no-one comes up with the website details.

Chris Morriss.

FrankDIY · 11th February 2004, 12:35 PM

Speakerworkshop can also do it with added mass.

Centauri · 11th February 2004, 12:59 PM

Quote:

Originally posted by miguel2
I must have a box to measure Vas. So I would have to build one to get that and then build another one...
Is there a way to go round this?

If you do use the box method, it certainly doesn't have to be a flash box. Offcuts of timber are good for this and it can be slapped together fairly quick as long as you get it sealed, and know the internal volume.

Cheers

richie00boy · 11th February 2004, 01:08 PM

Quote:

The problem is that if I understand correctly, I must have a box to measure Vas. So I would have to build one to get that and then build another one...
Is there a way to go round this?

Yes. And don't bother faffing around adding mass and measuring Fs again, it's a pain. Use the BL method, a quick search should reveal it, failing that it's fully explained in Vance Dickason's Loudspeaker Cookbook.

miguel2 · 11th February 2004, 05:11 PM

Does Speaker Workshop needs an amplifier in between the sound card and the driver or is it a direct connection with the 10R resistor only? How important is the power rating of the resistor?

Miguel

5th February 2004, 11:19 AM	#1
miguel2 diyAudio Member Join Date: Jun 2002 Location: Portugal	Subwoofer design with unknown driver Hi, I have a 12" driver that I think it is from Phillips (an old one). I am using it with the Pass design El-Pipe O, with good results. But now I having trouble in puting that big ugly tower in the living room, you know why dont you . So I though of using the driver in a box or something like that. But the problem is that I dont have any specs. Is there any decent way to do it? Miguel

5th February 2004, 01:19 PM	#3
FrankDIY diyAudio Member Join Date: Mar 2001 Location: Quebec City	SpeakerWorkshop works great to measure speaker parameters. __________________ Imagination is more important than knowledge. knowledge is limited, imagination encircles the world. Albert Einstein FrankDIY's Audio Corner

11th February 2004, 12:35 PM	#6
FrankDIY diyAudio Member Join Date: Mar 2001 Location: Quebec City	Speakerworkshop can also do it with added mass. __________________ Imagination is more important than knowledge. knowledge is limited, imagination encircles the world. Albert Einstein FrankDIY's Audio Corner

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5th February 2004, 01:14 PM	#2
Timn8ter diyAudio Member Join Date: Jul 2003 Location: Seattle, WA	If you have a multimeter perhaps this will help.

11th February 2004, 10:37 AM	#4
miguel2 diyAudio Member Join Date: Jun 2002 Location: Portugal	The problem is that if I understand correctly, I must have a box to measure Vas. So I would have to build one to get that and then build another one... Is there a way to go round this? Miguel

11th February 2004, 11:08 AM	#5
Ouroboros diyAudio Member Join Date: Dec 2003 Location: Nottingham UK	You can get a reasonable measure of Vas by adding a known mass to the cone and measuring the new (lower) resonant frequency. There's a site with a spreadsheet on it to calculate the parameters using this method. I've forgotten the URL though. I could email you the spreadsheet if no-one comes up with the website details. Chris Morriss.

11th February 2004, 05:11 PM	#9
miguel2 diyAudio Member Join Date: Jun 2002 Location: Portugal	Does Speaker Workshop needs an amplifier in between the sound card and the driver or is it a direct connection with the 10R resistor only? How important is the power rating of the resistor? Miguel

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