pinkmouse said:
My work PC (and sometimes lunch break) help me a great deal. The SW is an Adobe Acrobat of some sorts (Distiller windows PDF printer), I just press a botton in word and out comes a PDF.
I works really well
\Jens
Avi,
usually it is the other way around, but it should work if you can get enough delay. Try measuring the phase response of each driver, they may be close to being aligned as is.
usually it is the other way around, but it should work if you can get enough delay. Try measuring the phase response of each driver, they may be close to being aligned as is.
infinia said:
LOL - there are lots of volume controls already. I'm hoping that twisted pear will come out with a remote soon.
BobEllis said:
Bob,
Thanks for your quick answer, sorry if I'm asking a beginner questions, But how can I measure the phase response of the drivers?
One more- I'm not sure which Q to chose 0.5 or 0.7, any considerations for my speakers?
(Janszen Z2 CF- High:dipole electrostat, Low:dynamic 10" woofer in closed suspension, crossed at 800Hz ,original passive crossover is 12db/Oct, Electrostat Dispersion 100 degrees hoizontal, 60 vertical).
Is it possible to manage all the crossover considerations (for example how much to dip or peak in the crossover freq.) without actually measuring the frequency response in the listening room?
I appreciate very much your tremendous work in this group buy, and feels quite stupid to ask these questions now, when the time is to get the fumes out of my iron when building the PCB. but I'm sure that quick answer from you will save me a lot of time and mistakes.
Thanks,
Avi
Avi,
The answer to your questions is to measure the driver's acoustic response. You can use freeware such as Speaker Workshop or one of the many commercial measuremment programs.
You then adjust your crossover target resonse to suit.
The answer to your questions is to measure the driver's acoustic response. You can use freeware such as Speaker Workshop or one of the many commercial measuremment programs.
You then adjust your crossover target resonse to suit.
Avi,
To get a phase response with SW you can use for design purposes you have to be very careful in your measurements.
Look at the exact time and height of the stimulus pulse, (not the response pulse. When these are not identical for the measurement of each of the drivers , reject the measurement. Only in that case you get data that can be used.
Dick.
To get a phase response with SW you can use for design purposes you have to be very careful in your measurements.
Look at the exact time and height of the stimulus pulse, (not the response pulse. When these are not identical for the measurement of each of the drivers , reject the measurement. Only in that case you get data that can be used.
Dick.
Dick, Thanks for your comment,
I think I see what you mean. measuring the phase delay, it's like watching in scope the input and output signals of the driver simultaneously, measuring the delay, and do the same test to all drivers (I assume that the distance from the driver to the mic must be the same for all drivers!) and if i see changes in the recorded signal from driver to driver- I have to remeasure.
I have downloaded the Speaker Workshop freeware SW ,
But unfortunately, I can't see this software to perform this task.
Any other suggestions?
Avi
I think I see what you mean. measuring the phase delay, it's like watching in scope the input and output signals of the driver simultaneously, measuring the delay, and do the same test to all drivers (I assume that the distance from the driver to the mic must be the same for all drivers!) and if i see changes in the recorded signal from driver to driver- I have to remeasure.
I have downloaded the Speaker Workshop freeware SW ,
But unfortunately, I can't see this software to perform this task.
Any other suggestions?
Avi
Avi
It does. Just take the measurements and use them as they are. You don't get the delay as such but when adding or substrating the measurements the result will be as predicted by SW.
You'll have to experiment with active delay though, but you can make a first guess from the difference in depth of the drivers.
Look for the delay that gives the sharpest reduction in output at cross over (drivers out of phase).
Dick.
It does. Just take the measurements and use them as they are. You don't get the delay as such but when adding or substrating the measurements the result will be as predicted by SW.
You'll have to experiment with active delay though, but you can make a first guess from the difference in depth of the drivers.
Look for the delay that gives the sharpest reduction in output at cross over (drivers out of phase).
Dick.
I've missed this info:
Where is it shown how many OPA1234s are needed per (filter or PS) board?
Thanks
Where is it shown how many OPA1234s are needed per (filter or PS) board?
Thanks
The round 2 buy has been combined with the PSU buy http://www.diyaudio.com/wiki/index.php?page=PSU/Regulator+Boards+
Most invoices have been sent. the buy closes 14 April, if you want to order, contact me ASAP
Most invoices have been sent. the buy closes 14 April, if you want to order, contact me ASAP
Though I (think I) understand the concepts and theory on active cross overs I haven't any practical experience with building.
What sort of resistors and capacitors do you recommend?
On websites I see all sorts of things, like keramic, MKP, MKT, etc. I'm at a loss on this point. Help would be appreciated.
Then there is also the size. What are the demands on this point ?
Thanks,
Dick.
What sort of resistors and capacitors do you recommend?
On websites I see all sorts of things, like keramic, MKP, MKT, etc. I'm at a loss on this point. Help would be appreciated.
Then there is also the size. What are the demands on this point ?
Thanks,
Dick.
Caps and resistors are a personal choice thing.
I'd take a clue from Nelson Pass, who seems to use mainly Panasonic 1/4 watt 1% resistors. Resistor pads are 10mm pitch, so you might be able to use designer/mil spec resistors if you like.
As for caps, avoid ceramics. other than that, MKTs will probably be fine, although some prefer MKPs. Use 2% or better (or measure and pick from a lot of looser tolerance parts. A web search on LMS impedance bridge ought to help if you want to measure.) The maximum footprint is in the manual.
Here's the LMS bridge article - the bridge takes under a half hour to build on prototype board.
[PDF] An LMS Impedance BridgeFile Format: PDF/Adobe Acrobat - View as HTML
An LMS Impedance Bridge. By Dr George R. Steber, WB9LVI ... 12.99 pF to 0.129 ìF. Fig 5—Main window of the LMS impedance bridge program. ...
www.arrl.org/qex/2005/Steber.pdf - Similar pages
I'd take a clue from Nelson Pass, who seems to use mainly Panasonic 1/4 watt 1% resistors. Resistor pads are 10mm pitch, so you might be able to use designer/mil spec resistors if you like.
As for caps, avoid ceramics. other than that, MKTs will probably be fine, although some prefer MKPs. Use 2% or better (or measure and pick from a lot of looser tolerance parts. A web search on LMS impedance bridge ought to help if you want to measure.) The maximum footprint is in the manual.
Here's the LMS bridge article - the bridge takes under a half hour to build on prototype board.
[PDF] An LMS Impedance BridgeFile Format: PDF/Adobe Acrobat - View as HTML
An LMS Impedance Bridge. By Dr George R. Steber, WB9LVI ... 12.99 pF to 0.129 ìF. Fig 5—Main window of the LMS impedance bridge program. ...
www.arrl.org/qex/2005/Steber.pdf - Similar pages
Dick,
MKP caps are good, but IMHO Polystyrene are best choice But are bigger and more expensive (Farnel have the LCR 2.5% caps).
Avi
MKP caps are good, but IMHO Polystyrene are best choice But are bigger and more expensive (Farnel have the LCR 2.5% caps).
Avi
Not that it helps Dick a lot, but Mouser has polystyrene caps up to 10 nf that are quite inexpensive. They look to be film and foil, which supposedly sounds better than metalized film. The catch is that they are 10%, and the batch I bought used every bit of that tolerance and then some. I've been too busy organizing group buys to hook up the assembled boards, so I cannot give you a firsthand report on the sound impact.
I do like a polypropylene (MKP) capped XO better than an earlier version with MKTs. The caps weren't the ony changes, though, so it is not exactly a fair comparision.
I do like a polypropylene (MKP) capped XO better than an earlier version with MKTs. The caps weren't the ony changes, though, so it is not exactly a fair comparision.
Dick, the footprint for the capacitors is 7.5 x 5.5 mm.(max.) The pins are 5mm apart.
As Bob said, use at least MKT's.
MKP's are considered better and better still are FKP's.
Polystyrene are considered the best but are only limited available in this size and then only in small values.They are also sensitive to high temperature.(soldering)
In europe consider Wima FKP2,Vishay MKP1837,EMZ kp etc.
Use 2% or better or measure and select.
You can buy a capacitance meter for less then 30 Euro.(0.5% tolerance)
kro5998
As Bob said, use at least MKT's.
MKP's are considered better and better still are FKP's.
Polystyrene are considered the best but are only limited available in this size and then only in small values.They are also sensitive to high temperature.(soldering)
In europe consider Wima FKP2,Vishay MKP1837,EMZ kp etc.
Use 2% or better or measure and select.
You can buy a capacitance meter for less then 30 Euro.(0.5% tolerance)
kro5998
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