Newbie design

mikec · 1st April 2004, 10:26 AM

Hi.

I am new to speaker building so I want my first project to be mainly a learning exercise.
Therefore I have decided to try and make a Subwoofer out of parts I already have.
A friend recently gave me a set of speakers with 12 inch Dai1chi 120 watt speakers, plus I have a couple of reasonable quality 300 watt stereo amplifiers, so hopefully I can make something that doesnt sound to bad.
I would like some advice on what would be the best way to go:

Sealed or vented sub?
Dual 12inch drivers in one sub or two small subs?

Any existing plans that you know of that may be suitable would be greatly appreciated.

Thanks

Mike C

sreten · 1st April 2004, 06:49 PM

Without the driver parameters we cannot help,

sreten.

mikec · 2nd April 2004, 08:23 AM

After much searching, found the following info on the drivers
(Made a mistake in my last post-100W not 120W)

12" WOOFER 100W
Paper Cone.
Foam Surround.
Z 8W (7.2Wdc)
Freq. 33®4KHz
Fo 32Hz
Sens' 93dB
Magnet 30 Oz
Voice 38mm
Power 100W nom.
Qms 1.42
Qes 0.47
Qts 0.35
Vas 188.56L
Code SP12-100

Thanks

mikec · 2nd April 2004, 08:33 AM

After much searching, found the following info on the drivers
(Made a mistake in my last post-100W not 120W)

12" WOOFER 100W
Paper Cone.
Foam Surround.
Z 8W (7.2Wdc)
Freq. 33®4KHz
Fo 32Hz
Sens' 93dB
Magnet 30 Oz
Voice 38mm
Power 100W nom.
Qms 1.42
Qes 0.47
Qts 0.35
Vas 188.56L
Code SP12-100

Thanks

sreten · 2nd April 2004, 01:51 PM

some alignments for one driver,

sreten.

sreten · 2nd April 2004, 01:58 PM

Xmax is not given but here are some isobaric pair alignments,

sreten.

sreten · 2nd April 2004, 02:05 PM

JMO but a single 300w amplifier is way more than enough,
IMO you'd be a lot better off with the facilities provided
by a mono plate amplifier circa 150w for both drivers, e.g. :

http://www1.jaycar.com.au/productVie...=&SUBCATID=443

Note that an isobaric pair will be 1/4 of the size of a pair
used in parallel, but maximum output will be 6dB lower.

IMO the isobaric ~ 2 cuft ~ 60L tuned 30Hz looks good,
unless a big box is not a problem, then ~ 6cuft ~ 200L
tuned to 28Hz, drivers in parallel is the way to go.

sreten.

mikec · 5th April 2004, 02:03 AM

Thanks steren for the info, much appreciated.
A couple more questions:

With the isobaric option, does the box volume stay the same if you dont have the drivers configured in a clamshell arrangement, instead have one behind the other (cant remember what they call this config)?

Also I was trying to match your results by putting the driver info into WinIsp but my results never seemed to match yours- mainly in the single driver option- box always came out at 118 ltrs- This is the first time I have used this program so I guess I am doing something wrong or misinterpreting the driver data.
Can you show me the data you entered into the driver parameters?

Thanks again.

1st April 2004, 10:26 AM	#1
mikec diyAudio Member Join Date: Mar 2004 Location: Albany	Newbie design Hi. I am new to speaker building so I want my first project to be mainly a learning exercise. Therefore I have decided to try and make a Subwoofer out of parts I already have. A friend recently gave me a set of speakers with 12 inch Dai1chi 120 watt speakers, plus I have a couple of reasonable quality 300 watt stereo amplifiers, so hopefully I can make something that doesnt sound to bad. I would like some advice on what would be the best way to go: Sealed or vented sub? Dual 12inch drivers in one sub or two small subs? Any existing plans that you know of that may be suitable would be greatly appreciated. Thanks Mike C

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1st April 2004, 06:49 PM	#2
sreten diyAudio Member Join Date: Nov 2003 Location: Brighton UK	Without the driver parameters we cannot help, sreten.

2nd April 2004, 08:23 AM	#3
mikec diyAudio Member Join Date: Mar 2004 Location: Albany	After much searching, found the following info on the drivers (Made a mistake in my last post-100W not 120W) 12" WOOFER 100W Paper Cone. Foam Surround. Z 8W (7.2Wdc) Freq. 33®4KHz Fo 32Hz Sens' 93dB Magnet 30 Oz Voice 38mm Power 100W nom. Qms 1.42 Qes 0.47 Qts 0.35 Vas 188.56L Code SP12-100 Thanks

2nd April 2004, 08:33 AM	#4
mikec diyAudio Member Join Date: Mar 2004 Location: Albany	After much searching, found the following info on the drivers (Made a mistake in my last post-100W not 120W) 12" WOOFER 100W Paper Cone. Foam Surround. Z 8W (7.2Wdc) Freq. 33®4KHz Fo 32Hz Sens' 93dB Magnet 30 Oz Voice 38mm Power 100W nom. Qms 1.42 Qes 0.47 Qts 0.35 Vas 188.56L Code SP12-100 Thanks

2nd April 2004, 02:05 PM	#7
sreten diyAudio Member Join Date: Nov 2003 Location: Brighton UK	JMO but a single 300w amplifier is way more than enough, IMO you'd be a lot better off with the facilities provided by a mono plate amplifier circa 150w for both drivers, e.g. : http://www1.jaycar.com.au/productVie...=&SUBCATID=443 Note that an isobaric pair will be 1/4 of the size of a pair used in parallel, but maximum output will be 6dB lower. IMO the isobaric ~ 2 cuft ~ 60L tuned 30Hz looks good, unless a big box is not a problem, then ~ 6cuft ~ 200L tuned to 28Hz, drivers in parallel is the way to go. sreten.

5th April 2004, 02:03 AM	#8
mikec diyAudio Member Join Date: Mar 2004 Location: Albany	Thanks steren for the info, much appreciated. A couple more questions: With the isobaric option, does the box volume stay the same if you dont have the drivers configured in a clamshell arrangement, instead have one behind the other (cant remember what they call this config)? Also I was trying to match your results by putting the driver info into WinIsp but my results never seemed to match yours- mainly in the single driver option- box always came out at 118 ltrs- This is the first time I have used this program so I guess I am doing something wrong or misinterpreting the driver data. Can you show me the data you entered into the driver parameters? Thanks again.

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