Hello, I am soliciting suggestions for a crossover network!
For my 3.5 Loudspeaker project I’ve designed Zobel impedance correction circuits, assembled them and taken corrected DC voice coil impedance measurements from each one of my drivers.
Now that I have the corrected values, its time to design a crossover network of some sort or another.
Listed bellow are what I have been able to find of the Thiele / Small parameters and response charts, along with the Zobel corrected impedance values for each of my drivers.
Tweeter: Vifa D26TG-05-06
Response chart and specs:
http://www.madisound.com/pdf/vifa/d26tg-05-06e.pdf
Zobel corrected impedance 4.2 Ohms
Midrange: Peerless 832873 HDS 5-1/4"
Response chart and specs: http://www.speakerbits.com/net/catalogs/showpic1.aspx?id=PD150A
Zobel corrected impedance 5.8 Ohms
Woofer: Adire Audio AV 8
Response chart:
http://ldsg.snippets.org/graphics/adire/AV8full.jpg
Zobel corrected impedance 5.5 Ohms
Re (Ohms) 5.5Z
(Ohms) 8
Le (mH) 1.15
Fs (Hz) 35,8
Qms 4.19
Qes 0.43
Qts 0.39
VAS (L) 51.8
Sd (cm^2) 231
Xmax (mm) 6
Pmax (w) 100
SPL 89.3
Sub: Pyle PPA 15
Unable to find response chart.
Zobel corrected impedance 7.1 Ohms
Power (watts peak/rms) 800/250
Nom. Imp. 8 Ohms
FS (hz) 26.7
Qms 2.69
Qts 0.89
SPL(db) 90.2
VAS(cu ft) 11.357
Voice coil 2.5 KSV
Magnet 70 oz
Cone: paper
Surround: cloth
Spider: super
Dust cap: poly concave
Frame: stamped steel
Back plate: bumped and vented.
I’ve got an idea for the Pyle, I could go first order low pass since I’ve got iron core 18 gauge copper wire 12.7 mH inductors on hand which would cross at an actual 89 Hz @ 7.1 Ohms.
As for the AV8, I could go first order band pass. With a ten percent allowance (recommended to me by others here on DIY), high passing the AV8 at a stated 97.9Hz but an actual 107.69 Hz @ 5.5 Ohms with a 268.44 uF capacitor. Low passing the AV8 at a stated 300 Hz but an actual 270 Hz @ 5.5 Ohms with a 3.24 mH inductor.
As far as the Peerless and Vifa are concerned, I am out of my comfort zone.
Post Script: If any questions as to the very odd selection of drivers used in this project please see my original thread.
http://www.diyaudio.com/forums/showthread.php?threadid=145078&perpage=25&pagenumber=1
Please post any suggestions!
For my 3.5 Loudspeaker project I’ve designed Zobel impedance correction circuits, assembled them and taken corrected DC voice coil impedance measurements from each one of my drivers.
Now that I have the corrected values, its time to design a crossover network of some sort or another.
Listed bellow are what I have been able to find of the Thiele / Small parameters and response charts, along with the Zobel corrected impedance values for each of my drivers.
Tweeter: Vifa D26TG-05-06
Response chart and specs:
http://www.madisound.com/pdf/vifa/d26tg-05-06e.pdf
Zobel corrected impedance 4.2 Ohms
Midrange: Peerless 832873 HDS 5-1/4"
Response chart and specs: http://www.speakerbits.com/net/catalogs/showpic1.aspx?id=PD150A
Zobel corrected impedance 5.8 Ohms
Woofer: Adire Audio AV 8
Response chart:
http://ldsg.snippets.org/graphics/adire/AV8full.jpg
Zobel corrected impedance 5.5 Ohms
Re (Ohms) 5.5Z
(Ohms) 8
Le (mH) 1.15
Fs (Hz) 35,8
Qms 4.19
Qes 0.43
Qts 0.39
VAS (L) 51.8
Sd (cm^2) 231
Xmax (mm) 6
Pmax (w) 100
SPL 89.3
Sub: Pyle PPA 15
Unable to find response chart.
Zobel corrected impedance 7.1 Ohms
Power (watts peak/rms) 800/250
Nom. Imp. 8 Ohms
FS (hz) 26.7
Qms 2.69
Qts 0.89
SPL(db) 90.2
VAS(cu ft) 11.357
Voice coil 2.5 KSV
Magnet 70 oz
Cone: paper
Surround: cloth
Spider: super
Dust cap: poly concave
Frame: stamped steel
Back plate: bumped and vented.
I’ve got an idea for the Pyle, I could go first order low pass since I’ve got iron core 18 gauge copper wire 12.7 mH inductors on hand which would cross at an actual 89 Hz @ 7.1 Ohms.
As for the AV8, I could go first order band pass. With a ten percent allowance (recommended to me by others here on DIY), high passing the AV8 at a stated 97.9Hz but an actual 107.69 Hz @ 5.5 Ohms with a 268.44 uF capacitor. Low passing the AV8 at a stated 300 Hz but an actual 270 Hz @ 5.5 Ohms with a 3.24 mH inductor.
As far as the Peerless and Vifa are concerned, I am out of my comfort zone.
Post Script: If any questions as to the very odd selection of drivers used in this project please see my original thread.
http://www.diyaudio.com/forums/showthread.php?threadid=145078&perpage=25&pagenumber=1
Please post any suggestions!
How did you measure the impedance? A DC multimeter is not going to read correctly because the cap in the zobel will not be "seen".
Designing any speaker with textbook values is not a good idea, but trying to do a 3.5-way is near impossible. I would focus on making a 2-way with the Peerless woofer and Vifa tweeter, somehow correcting for baffle step, and add the Pyle as a bass bin, and cross it low to the mid/tweeter with a cheap active crossover like the Behringer CX3210. Just my .02
Designing any speaker with textbook values is not a good idea, but trying to do a 3.5-way is near impossible. I would focus on making a 2-way with the Peerless woofer and Vifa tweeter, somehow correcting for baffle step, and add the Pyle as a bass bin, and cross it low to the mid/tweeter with a cheap active crossover like the Behringer CX3210. Just my .02
Something that uses an AC signal to measure impedance. The Zobel calculators I've seen calculate the predicted impedance (or maybe it was just DCR) of the driver after the Zobel is in place. What did the one you use say?
BTW you don't need one the tweeter, won't need one the Adire if you don't use it (I wouldn't) and don't need one on the Pyle if you use an active crossover.
BTW you don't need one the tweeter, won't need one the Adire if you don't use it (I wouldn't) and don't need one on the Pyle if you use an active crossover.
This is the calculator I used for the zobel vaues.
http://diyaudioprojects.com/Technical/Speaker-Zobel/
This calculator does not predict the corrected impedance.
The calculators Ive seen for crossover values seem to ask for DC resistance, dont they?
Bill.
http://diyaudioprojects.com/Technical/Speaker-Zobel/
This calculator does not predict the corrected impedance.
The calculators Ive seen for crossover values seem to ask for DC resistance, dont they?
Bill.
richie00boy said:
Thanks for the post richie00boy!
As for Zobel calculators not using DC resistance to calculate component values, here is a qoute from the above referenced Zobel calculators supporting text: "Where:
•Re is the DC Resistance of the driver [ohms]
•Le is the Voice coil Inductance of the driver [H]
•Rz is the calculated Zobel resistor [ohms] and
•Cz is the calculated Zobel capacitor [F].
Use this online calculator to determine the required Zobel resistor and capacitor. Simply enter Re and Le into the boxes below and click the CALCULATE button. Use the CLEAR button to reset all the values."
I also have found simular text on many other sites dedicated to Zobel networks.
Can you please rectify this for me?
Bill.
OK
Hi Bill; as you can tell from the responses so far most people think that this is difficult going on impossible
I disagree; it is just hard
If you are going to swap-out the Pyle in the future for that other 15 inch driver I'd disregard it at this stage.
As you have made Zobels for the drivers already then the impedance should be relatively flat ( which is an excellent starting point )
1 / if you low pass -high pass the Adire it has become a 4-Way, Don't do that. Inductor values are too big, the .5 woofer is to boost the low bass so you want the Adire 8 to run from Fs/Fb to where you cross to the Peerless Mid-range.
2 / Run the mid-range as wide as possible; 300 to 3000 is what I would recommend.
3 / 10% is good as it stops overlapping, so yes cross the Adire 1st order at 270hz
4/ recalculate the XO for the tweeter using 3300 ( won't be too far removed from previous values )
5 / I think you will need to use second order XO for the Peerless at 300Hz but at the top end it already has a reasonably smooth second order roll-off so a first order should work at 3000Hz
6 / Do all of this outboard of the box as it will need tweaking.
7 / When all of this is done, then play with the .5 woofer with the biggest coil you can afford.
You already have that 12.7mH coil, it may be usable for a Linkwitz-Riley (L/R ) XO down low.
Do you have the formulae for calculating crossovers? I can't remember
This is where the fun starts.
Regards
Ted
Hi Bill; as you can tell from the responses so far most people think that this is difficult going on impossible
I disagree; it is just hard
If you are going to swap-out the Pyle in the future for that other 15 inch driver I'd disregard it at this stage.
As you have made Zobels for the drivers already then the impedance should be relatively flat ( which is an excellent starting point )
1 / if you low pass -high pass the Adire it has become a 4-Way, Don't do that. Inductor values are too big, the .5 woofer is to boost the low bass so you want the Adire 8 to run from Fs/Fb to where you cross to the Peerless Mid-range.
2 / Run the mid-range as wide as possible; 300 to 3000 is what I would recommend.
3 / 10% is good as it stops overlapping, so yes cross the Adire 1st order at 270hz
4/ recalculate the XO for the tweeter using 3300 ( won't be too far removed from previous values )
5 / I think you will need to use second order XO for the Peerless at 300Hz but at the top end it already has a reasonably smooth second order roll-off so a first order should work at 3000Hz
6 / Do all of this outboard of the box as it will need tweaking.
7 / When all of this is done, then play with the .5 woofer with the biggest coil you can afford.
You already have that 12.7mH coil, it may be usable for a Linkwitz-Riley (L/R ) XO down low.
Do you have the formulae for calculating crossovers? I can't remember
This is where the fun starts.
Regards
Ted
I have been doing some calculations for you Bill
If I can't make speakers for myself ATM I can help you.
I checked the Ballpark impedance, and using 6.5ohms ( which is close enough ) for the Peerless mid and using a simple Linkwitz Riley XO at 300HzI get these figures
A 40 uF cap in series and a 6.8mH inductor in parallel, at the top end; if I use your value of 5.5R I'd be using a single low DCR coil of 0.29mH, if however the impedance is stabilized at 8Ohms, then that value is 3.3mH.
I'd go with a standard value and change the resistor value in the Zobel until it sounds best, which is why outboard XOs are so useful.
At 270/350 Hz the little Adire woofers impedance is going to be very close to the DCR so I agree with the inductor value of 3.24mH for a first order low-pass
If I can't make speakers for myself ATM I can help you.
I checked the Ballpark impedance, and using 6.5ohms ( which is close enough ) for the Peerless mid and using a simple Linkwitz Riley XO at 300HzI get these figures
A 40 uF cap in series and a 6.8mH inductor in parallel, at the top end; if I use your value of 5.5R I'd be using a single low DCR coil of 0.29mH, if however the impedance is stabilized at 8Ohms, then that value is 3.3mH.
I'd go with a standard value and change the resistor value in the Zobel until it sounds best, which is why outboard XOs are so useful.
At 270/350 Hz the little Adire woofers impedance is going to be very close to the DCR so I agree with the inductor value of 3.24mH for a first order low-pass
It has just now dawned on me that I forgot to list the values of the Zobel network components! I will remedy this now. Bellow are listed the values I used.
Vifa = 6 ohm resistor and 2.2 uF capacitor.
Peerless = 7.6 Ohm resister and 14.2 uF capacitor.
AV8 = 7 Ohm resistor and 24.2 uF capacitor.
Pyle = 7.6 Ohm resistor and 17.2 uF capacitor.
Vifa = 6 ohm resistor and 2.2 uF capacitor.
Peerless = 7.6 Ohm resister and 14.2 uF capacitor.
AV8 = 7 Ohm resistor and 24.2 uF capacitor.
Pyle = 7.6 Ohm resistor and 17.2 uF capacitor.
I make the Zobel value for the midrange Peerless to be 22uF and 7.5R, 10 watts
As I said earlier, Zobels are used to flatten and maintain a constant impedance
value that is close to the nominal.
It simply isn't needed when used close to the drivers resonant frequency.
Those values for the Pyle look suspect, but you can save money by leaving
them out.
i make the values for the Adire woofer to be 50uF and 5.6/6.8R and that is a 10 watt resistor
As I said earlier, Zobels are used to flatten and maintain a constant impedance
value that is close to the nominal.
It simply isn't needed when used close to the drivers resonant frequency.
Those values for the Pyle look suspect, but you can save money by leaving
them out.
i make the values for the Adire woofer to be 50uF and 5.6/6.8R and that is a 10 watt resistor
Bill, check out Petes new post, good stuff from your beginners point of view.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=146785
http://www.diyaudio.com/forums/showthread.php?s=&threadid=146785
I used the formula in the "Loudspeaker Design Cookbook" and I think I used the nominal DCR value.
This is one of those times when the crossover selected needs to be built and tested, without some sophisticated design programs and testing gear, all the formulas can do is get us close to what we want; from then on it is listen/ change a value / listen again and repeat: repeat again until it is right, see what I mean by fun??
If you use a Zobel and start to change values what you have is what is called a "Strange" second order XO, this is what cross-over optimizers are good at.
Honestly; I don't think it matters too much which Zobel values you pick; as we will be tweaking when you first listen.
Remembering that most of the music is in the midrange, so concentrate on that first.
BTW; if those Peerless are still on special, they to would be reasonable for Home theater, as 2.5 ways to allow deeper bass and better power handling
This is one of those times when the crossover selected needs to be built and tested, without some sophisticated design programs and testing gear, all the formulas can do is get us close to what we want; from then on it is listen/ change a value / listen again and repeat: repeat again until it is right, see what I mean by fun??
If you use a Zobel and start to change values what you have is what is called a "Strange" second order XO, this is what cross-over optimizers are good at.
Honestly; I don't think it matters too much which Zobel values you pick; as we will be tweaking when you first listen.
Remembering that most of the music is in the midrange, so concentrate on that first.
BTW; if those Peerless are still on special, they to would be reasonable for Home theater, as 2.5 ways to allow deeper bass and better power handling
I am beginning to see the light!
I’ve cut some “planks” out of MDF to mount the crossover components to, for access outside the cabinet.
I now see why you wouldn’t high pass the AV8, however what does one do about the peak at resonance?
As far as focusing on the midrange,
“5 / I think you will need to use second order XO for the Peerless at 300Hz but at the top end it already has a reasonably smooth second order roll-off so a first order should work at 3000Hz” I think that is wise advice.
What then of the Vifa?
Bill.
P.S. My computer says its 2:35 PM in Norlane, my wife wants to know what wednessday looks like?
I’ve cut some “planks” out of MDF to mount the crossover components to, for access outside the cabinet.
I now see why you wouldn’t high pass the AV8, however what does one do about the peak at resonance?
As far as focusing on the midrange,
“5 / I think you will need to use second order XO for the Peerless at 300Hz but at the top end it already has a reasonably smooth second order roll-off so a first order should work at 3000Hz” I think that is wise advice.
What then of the Vifa?
Bill.
P.S. My computer says its 2:35 PM in Norlane, my wife wants to know what wednessday looks like?
What peak?? an audible one or an impedance one; if you look at the performance graph for the Adire you don't see an audible peak, so any peak must be in the impedance , which is usually around Fs, as you are crossing this driver at 270, theoretically the driver impedance should be the same as its DCR.
Most woofers are close to the DCR around there, makes XOs easier sometimes.
So for designing this XO, I looked at the audibility of peaks and picked an area that is reasonably flat ( sonically ) for an octave above and below the XO frequency, 300 fits this ball-park for both the woofer and the mid-range.
I haven't really thought out my design criteria the way that Pete has; his method is more efficient in brain time than mine but I usually get there in the end.
Now for the tweeter, it is operating closer to resonance than the midrange so it NEEDS a second order XO to stop as much of the low frequencies getting through as possible, and the Linkwitz-Riley crossover has better electrical damping than Butterworth, and when summing first and second order XOs, I find that the transition from one slope to the other is better sounding that way, other designers and builders will disagree.
I have a very experienced friend who NEVER uses anything but first order crossovers.
Here in Geelong area it is winter, the day started with gale force winds and 7C, went on to become sunny and 16C, now it is cold and rain is coming as the wind switches from a warm Northerly to a chilly SouthWesterly ( Antarctic air)
Troels site is a treasure trove of ideas and designs.
http://www.troelsgravesen.dk/coils.htm
Print this out and put it near your work-bench
And I like Rods political outlook and willingness to share, also he is an Aussie and we need your money ( he sells boards )
http://sound.westhost.com/lr-passive.htm
It helps when you know what terms to search under
http://www.troelsgravesen.dk/coils.htm
Print this out and put it near your work-bench
And I like Rods political outlook and willingness to share, also he is an Aussie and we need your money ( he sells boards )
http://sound.westhost.com/lr-passive.htm
It helps when you know what terms to search under
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