Pluto sub - Peerles 830668

peter_m · 8th January 2008, 05:53 AM

http://www.linkwitzlab.com/Pluto/subwoofer.htm
http://www.linkwitzlab.com/filters.htm#9

This design can use an inexpensive 10" sub in a relatively small enclosure (15L) with the use of an electronic EQ. Anyone have experience with this design? Any counter indications to use it with a pair of Zaph's B3S?

Peter

EDIT: I have the C and R values but I am not sure where to put them on this diagram... Any help?

iUSERTLO72p · 8th January 2008, 06:26 AM

http://sound.westhost.com/project71.htm

http://sound.westhost.com/project48.htm

http://sound.westhost.com/linkwitz-transform.htm

Ping for richie00boy

iUSERTLO72p

peter_m · 8th January 2008, 06:45 AM

I'll see you on the dark side my friend. Great Links!

peter_m · 10th January 2008, 05:21 AM

Hum..... for the 830668 values... should I just use what Linkwitz calculated (f0 = 74.3 Hz & Q0 = 1.57) ?

Or should I use the Peerless data for Fs = 33Hz, Qts = 0.51, Vas = 69L to calculate my own f0 = 80.3Hz & Q0 = 1.24 ????

What to do? Does anyone know if this will work for a sub x-over of 150 hz?

Peter

gfiandy · 12th January 2008, 09:12 PM

I am a little confused by what you are asking however I have tryed to answer what I think your question was.

The Linkwitz transform should be used to correct the LF part of the bass response it has little or no effect on the crossover to the main speakers.

You should calculate the characterisitcs of your drive unit in the box you intend to use it in and then decide on what response you would like to have. Take into account that if you try to push the response too low you will either over extend the drive unit mechanically and damage the surround or electrically and burn out the voice coil. Use this data to calculate the required transform components.

The drive unit will easly output upto 150Hz so you can crossover there if you want to. However for crossover frequency of above about 100Hz you need to keep the sub very near to the main speakers as you ear can start to localise that the LF sound is not comming from the same place as the mid/hf.

Regards,
Andrew

peter_m · 12th January 2008, 10:55 PM

Maybe I was not clear with my questions. I apologize but you understood right, it was 2 parts.

1) I wanted to build the exact same enclosure and use the same driver as SL used in this page: http://www.linkwitzlab.com/Pluto/subwoofer.htm This would keep it simple for me by following a tried and tested design. Also found an excel spreadsheet that calculates Fo & Qo based on Fs, Qts & Vas from here: http://sound.westhost.com/linkwitz-transform.htm and decided to test SL's numbers. When I plugged in the data from the Peerless website, the calculated Fo and Qo did not match SL's measured Fo and Qo... Should I use the data from Linkwitz's measurements or the data generated by the spreadsheet? That was my original question but I have been shown how to make my own measurement with this: http://www.linkwitzlab.com/images/graphics/f0Q0.gif and will do so when I receive the driver. Apparently I am not the only one to have noticed discrepancies as someone else is the Linkwitz forum made his own measurements and they don't match either.

2) 150hz is the x-over frequency to integrate the sub to my satellites drivers. Great to know the sub will go that high. I know I will have to centre it between the satellites for best results. Thanks

Regards,

Peter

gfiandy · 13th January 2008, 01:18 PM

Thanks for your clarification. I would agree that it is best to make your own measurements as drive units characteristics do vary.

I recomend running the drive unit in before taking any measurements as they can change quite alot as the suspension sofens up a bit.

Regards,
Andrew

richie00boy · 13th January 2008, 01:41 PM

Your own measurements would be best, but if you don't have them I would use Linkwitz's values as he has nothing to hide.

Regarding where to put the R and C values if you just building the EQ part, look between TP2 and TP3 on the schematic on the Pluto page, it's all there already.

culcanmar · 13th January 2008, 02:56 PM

Peter,

I have been building the same subwoofer you are. I was also wondering if I would use the parameters on Linkwitz's website, but after building my enclosure and making measurements I found that mine differ very little. I use somewhat different component values for the filtering - not shure what @ the moment since it is on breadboard on top of my amp about 2,3 meters above the floor - but if you want I could look it up for you.

Btw, I tried how much the subwoofer could take and I was only able to overdrive the unit when playing some testtrack with a helicopter @ 12 Hz making the windows throughout the house ring.

Good luck on you build!

Martin

peter_m · 13th January 2008, 03:56 PM

Wow Thanks guys! For a while I was starting to get nervous about the sub. I have already ordered the driver and was beginning to think it was an obscure and not so popular design... confidence is restored

How long till the driver breaks in and it's specs stop changing? Can I just use a 20hz signal to give it a good workout while I am out of the house?

Also, since I am letting to sub go as high as 150hz, should I have it forward firing like a woofer, or should I keep it in a down firing position?

Glad to know I will be able to shake some windows

Will post my results when enclosure is built and everything is up and running.

Peter

8th January 2008, 06:26 AM	#2
iUSERTLO72p diyAudio Member Join Date: Oct 2007	More info http://sound.westhost.com/project71.htm http://sound.westhost.com/project48.htm http://sound.westhost.com/linkwitz-transform.htm Ping for richie00boy iUSERTLO72p

13th January 2008, 01:41 PM	#8
richie00boy Did it Himself diyAudio Member Join Date: Nov 2003 Location: Gloucestershire, England, UK	Your own measurements would be best, but if you don't have them I would use Linkwitz's values as he has nothing to hide. Regarding where to put the R and C values if you just building the EQ part, look between TP2 and TP3 on the schematic on the Pluto page, it's all there already. __________________ www.readresearch.co.uk my website for UK diy audio people - designs, PCBs, kits and more

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8th January 2008, 06:45 AM	#3
peter_m diyAudio Member Join Date: May 2007	I'll see you on the dark side my friend. Great Links!

10th January 2008, 05:21 AM	#4
peter_m diyAudio Member Join Date: May 2007	Hum..... for the 830668 values... should I just use what Linkwitz calculated (f0 = 74.3 Hz & Q0 = 1.57) ? Or should I use the Peerless data for Fs = 33Hz, Qts = 0.51, Vas = 69L to calculate my own f0 = 80.3Hz & Q0 = 1.24 ???? What to do? Does anyone know if this will work for a sub x-over of 150 hz? Peter

12th January 2008, 09:12 PM	#5
gfiandy Audio Engineer diyAudio Member Join Date: Jul 2003 Location: Cambridge UK	I am a little confused by what you are asking however I have tryed to answer what I think your question was. The Linkwitz transform should be used to correct the LF part of the bass response it has little or no effect on the crossover to the main speakers. You should calculate the characterisitcs of your drive unit in the box you intend to use it in and then decide on what response you would like to have. Take into account that if you try to push the response too low you will either over extend the drive unit mechanically and damage the surround or electrically and burn out the voice coil. Use this data to calculate the required transform components. The drive unit will easly output upto 150Hz so you can crossover there if you want to. However for crossover frequency of above about 100Hz you need to keep the sub very near to the main speakers as you ear can start to localise that the LF sound is not comming from the same place as the mid/hf. Regards, Andrew

12th January 2008, 10:55 PM	#6
peter_m diyAudio Member Join Date: May 2007	Maybe I was not clear with my questions. I apologize but you understood right, it was 2 parts. 1) I wanted to build the exact same enclosure and use the same driver as SL used in this page: http://www.linkwitzlab.com/Pluto/subwoofer.htm This would keep it simple for me by following a tried and tested design. Also found an excel spreadsheet that calculates Fo & Qo based on Fs, Qts & Vas from here: http://sound.westhost.com/linkwitz-transform.htm and decided to test SL's numbers. When I plugged in the data from the Peerless website, the calculated Fo and Qo did not match SL's measured Fo and Qo... Should I use the data from Linkwitz's measurements or the data generated by the spreadsheet? That was my original question but I have been shown how to make my own measurement with this: http://www.linkwitzlab.com/images/graphics/f0Q0.gif and will do so when I receive the driver. Apparently I am not the only one to have noticed discrepancies as someone else is the Linkwitz forum made his own measurements and they don't match either. 2) 150hz is the x-over frequency to integrate the sub to my satellites drivers. Great to know the sub will go that high. I know I will have to centre it between the satellites for best results. Thanks Regards, Peter

13th January 2008, 01:18 PM	#7
gfiandy Audio Engineer diyAudio Member Join Date: Jul 2003 Location: Cambridge UK	Thanks for your clarification. I would agree that it is best to make your own measurements as drive units characteristics do vary. I recomend running the drive unit in before taking any measurements as they can change quite alot as the suspension sofens up a bit. Regards, Andrew

13th January 2008, 02:56 PM	#9
culcanmar diyAudio Member Join Date: Feb 2003 Location: Lopik weekends, Enschede during the week	Peter, I have been building the same subwoofer you are. I was also wondering if I would use the parameters on Linkwitz's website, but after building my enclosure and making measurements I found that mine differ very little. I use somewhat different component values for the filtering - not shure what @ the moment since it is on breadboard on top of my amp about 2,3 meters above the floor - but if you want I could look it up for you. Btw, I tried how much the subwoofer could take and I was only able to overdrive the unit when playing some testtrack with a helicopter @ 12 Hz making the windows throughout the house ring. Good luck on you build! Martin

13th January 2008, 03:56 PM	#10
peter_m diyAudio Member Join Date: May 2007	Wow Thanks guys! For a while I was starting to get nervous about the sub. I have already ordered the driver and was beginning to think it was an obscure and not so popular design... confidence is restored How long till the driver breaks in and it's specs stop changing? Can I just use a 20hz signal to give it a good workout while I am out of the house? Also, since I am letting to sub go as high as 150hz, should I have it forward firing like a woofer, or should I keep it in a down firing position? Glad to know I will be able to shake some windows Will post my results when enclosure is built and everything is up and running. Peter