By the way... nice looking speakers. May be I will make something like these for my computer....
thanks 🙂 It looks like it won't be too long before you are moving from the theoretical to the practical!
Tony.
Tony.
how can the separate baffle be 5mm? is the tweeter faceplate 5mm thick?
also your crossover is not good you wont like the sound. 1st order will give you lots of lobing. Use a 4th order.
Hi Prasi, Either way would work. I'm guessing you are planning on doing the 5mm plate because it is easier than countersinking?
If you have a circle jig and a router http://www.diyaudio.com/forums/equipment-tools/226853-diy-circle-jig.html It is not that hard to do the rebate. You just need to set the depth of the router accurately (use some scrap to test on first), and make sure you do the rebate first, and then the inner hole.
On the crossover without any actual speaker measurements (or manufacturers response curves) it is a bit of a lucky dip. Be prepared to try a lot of different options 🙂
Tony.
If you have a circle jig and a router http://www.diyaudio.com/forums/equipment-tools/226853-diy-circle-jig.html It is not that hard to do the rebate. You just need to set the depth of the router accurately (use some scrap to test on first), and make sure you do the rebate first, and then the inner hole.
On the crossover without any actual speaker measurements (or manufacturers response curves) it is a bit of a lucky dip. Be prepared to try a lot of different options 🙂
Tony.
Dear Tony, to be honest, I have zero knowledge of woodworking. I will be taking help of professional carpenter to build cabinets. In that case, yes may be I show him your above post , leave it him to figure out how to countersink.
Today, I got my xover components (calculations based on the sticky thread guidelines by AllenB).I have followed the steps religiously (as I am a newbie) to calculate the values of each components. I dont know whit about electrical circuits, But I am beginning to!!.
My circuit is an exact replica (as far as the order is concerned ) of the AllenB's example circuit. However I am still unclear about the phase difference between when using first order for low pass and 2nd order for high pass. From practical point view (considering my limited knowledge), will reversing polarity of tweeter solve the issue of phase difference? (My low pass just uses an inductor and a zobel circuit (for impedance flattening)) and high pass section is based on second order Butterworth (and L-pad for attenuating the tweeter). the image is attached again below for your reference.
Today, I got my xover components (calculations based on the sticky thread guidelines by AllenB).I have followed the steps religiously (as I am a newbie) to calculate the values of each components. I dont know whit about electrical circuits, But I am beginning to!!.
My circuit is an exact replica (as far as the order is concerned ) of the AllenB's example circuit. However I am still unclear about the phase difference between when using first order for low pass and 2nd order for high pass. From practical point view (considering my limited knowledge), will reversing polarity of tweeter solve the issue of phase difference? (My low pass just uses an inductor and a zobel circuit (for impedance flattening)) and high pass section is based on second order Butterworth (and L-pad for attenuating the tweeter). the image is attached again below for your reference.
dear lilun,
This is my first bookshelf. I am trying to keep it simple. Also I dont have FR and impedance curves of drivers. I want this system to be my workshop, my learning experience. Hence the design. I am sorry if you dont like it....
This is my first bookshelf. I am trying to keep it simple. Also I dont have FR and impedance curves of drivers. I want this system to be my workshop, my learning experience. Hence the design. I am sorry if you dont like it....
Hi Prassi, I would have to read the thread again to be sure but I would think that the difference in orders between the two filters would be due to differing phase characteristics of the drivers. In my MTM crossover I have a second order on the low pass and third order on the high pass, which overall results in a 4th order acoustic crossover.
The difference in electrical order actually lines up the phase (in my case) very well.
If you have a webcam or other cheap computer microphone you can do some basic measurements using free software such as holm impulse, although they won't be accurate, you can see whether the tweeter should be inverted or not by the dip or otherwise at the crossover frequenccy 🙂
Tony.
The difference in electrical order actually lines up the phase (in my case) very well.
If you have a webcam or other cheap computer microphone you can do some basic measurements using free software such as holm impulse, although they won't be accurate, you can see whether the tweeter should be inverted or not by the dip or otherwise at the crossover frequenccy 🙂
Tony.
Hi,
http://sites.google.com/site/undefinition/diy
(see if nothing else, the excellent FAQs)
The Speaker Building Bible
Zaph|Audio
http://audio.claub.net/Simple Loudspeaker Design ver2.pdf
FRD Consortium tools guide
Designing Crossovers with Software Only
You have x/o design issues, see the above links.
rgds, sreten.
http://sites.google.com/site/undefinition/diy
(see if nothing else, the excellent FAQs)
The Speaker Building Bible
Zaph|Audio
http://audio.claub.net/Simple Loudspeaker Design ver2.pdf
FRD Consortium tools guide
Designing Crossovers with Software Only
You have x/o design issues, see the above links.
rgds, sreten.
Hi Sreten, The biggest issue is there is no FR data available for the woofers (that I am aware of). Flying blind so to speak!
But do read and absorb those links prassi, a wealth of information 🙂 and if you do find measurements, then I would highly recommend following the procedure outlined in this link http://audio.claub.net/Simple%20Loudspeaker%20Design%20ver2.pdf posted by Sreten.
Tony.
But do read and absorb those links prassi, a wealth of information 🙂 and if you do find measurements, then I would highly recommend following the procedure outlined in this link http://audio.claub.net/Simple%20Loudspeaker%20Design%20ver2.pdf posted by Sreten.
Tony.
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Dear Tony and Sreten,
Thank you very much for the links and info. I go through each of them in detail. And then come back to you if I have any doubts (I hope you will continue your support and help with my project!)
regards
Prashant
Thank you very much for the links and info. I go through each of them in detail. And then come back to you if I have any doubts (I hope you will continue your support and help with my project!)
regards
Prashant
hi Sreten,
One basic question about Zobel network. The voice coil inductance value to be used for calculating capacitance is @1kHz or 10kHz. I have both the values with me.
regards,
prasi
One basic question about Zobel network. The voice coil inductance value to be used for calculating capacitance is @1kHz or 10kHz. I have both the values with me.
regards,
prasi
Dear Tony,
Can you answer my above question.? i.e., In calculation of capacitance value in Zobel circuit for woofer, whether we have to use voice coil inductance value at 1 kHz or at 10 kHz.
Can you answer my above question.? i.e., In calculation of capacitance value in Zobel circuit for woofer, whether we have to use voice coil inductance value at 1 kHz or at 10 kHz.
Hi Prasi, that is a good question and I don't know the answer. What I suspect is that you probably should use the value that is at the frequency that the woofers impedance starts to rise above the level that you want to flatten it to.
If you have an impedance measurement of the woofer then I would suggest doing a simulation rather than a theoretical zobel calculation. Speaker workshop is very good for simulating zobels (and in fact will look at the impedance curve and calculate good values for you automatically).
I think I posted a link earlier to Claudio's cable jig. I'd highly recommend doing impedance measurements, they are not difficult and will put you well ahead when making decisions about your crossover.
Tony.
If you have an impedance measurement of the woofer then I would suggest doing a simulation rather than a theoretical zobel calculation. Speaker workshop is very good for simulating zobels (and in fact will look at the impedance curve and calculate good values for you automatically).
I think I posted a link earlier to Claudio's cable jig. I'd highly recommend doing impedance measurements, they are not difficult and will put you well ahead when making decisions about your crossover.
Tony.
Hi Tony,
Writing after long time as I was busy in building speakers. I have finally Completed building my Speakers. I have not followed your valuable suggestions on measurements of impedence to do sim in Speaker Workshop software. I went ahead with the theoretical calculations for xover.
Cabinet Finish: Not very top class but acceptable quality (you comment about finish when I post some pics)
Listening impressions:
1. Much much better than what I was listening to earlier on my Sony "hi-fi" system speakers and Phillips "Hi-Fi" speakers (so called).
2. Bass is very crisp yet deep.
3. I think I have to reduce the tweeter level somewhat ( or can playing with Treble knob on amp will suffice?)
Thank you for all the help extended to me, especially where you suggested to change the driver to reduce the number of step response wiggles. I am very satisfied with the sound quality.
Now I am planning to make measurement (FR and imp) of the entire box and I will be needing your help to do it accurately. Hope you will continue your support.
P.S. I will post some photographs soon.
Hi Prasi, good to hear that you have made progress and are happy with the results! 🙂 reducing tweeter level can be done using an lpad (do a search on lpad) Quite easy to calculate, though you need to have an idea how much cut you need.
You can also try simply putting a resistor in series with the tweeter. Do it before the tweeters crossover components though or you will shift your crossover point. If just trying a series resistor try with something like 2 or 3 ohms as a starting point. But measurements (if you do accoustic) will give you a much better idea of what is going on.
Tony.
You can also try simply putting a resistor in series with the tweeter. Do it before the tweeters crossover components though or you will shift your crossover point. If just trying a series resistor try with something like 2 or 3 ohms as a starting point. But measurements (if you do accoustic) will give you a much better idea of what is going on.
Tony.
Hi tony ,
I have already used an L pad. 4ohms in series and 10ohms in parallel. I will definately do it before tweeter comps. thanks for the inputs. But can I do it amplifier treble settings?
I have already used an L pad. 4ohms in series and 10ohms in parallel. I will definately do it before tweeter comps. thanks for the inputs. But can I do it amplifier treble settings?
There is no reason you can't use the trebel control on the amplifier, that's what it is for, any particular speaker in a particular room may need some level of eq, the tone controls will let you make some adjustments to suit your tastes 🙂
What you may find the cause is, is Baffle Step. Are the speakers a reasonable distance from the wall, or close to the wall. If they are close then baffle step is less of an issue, but if they are out from the wall then you may find the balance off a bit. Once you start doing measurements it should be clearer.
You may need additional cut in your lpad, especially if you have only dropped the tweeters by the difference in sensitivity between the woofers and the tweeter (again due to baffle step).
Tony.
What you may find the cause is, is Baffle Step. Are the speakers a reasonable distance from the wall, or close to the wall. If they are close then baffle step is less of an issue, but if they are out from the wall then you may find the balance off a bit. Once you start doing measurements it should be clearer.
You may need additional cut in your lpad, especially if you have only dropped the tweeters by the difference in sensitivity between the woofers and the tweeter (again due to baffle step).
Tony.
Hi Tony,
Speakers are quite close to the wall, about 6 inches. And In calculation of L-pad, I have dropped the tweeter level equal to the difference in sensitivity plus 2-3 dB more.
I hope to start measurement soon. I need some initial guidance from you. Could you point me to some of the websites where I can find comprehensive info on measurement procedure and equipments ?
Regards
Prasi
Hi Prasi, this page should help you to get started Red Spade Audio: How to measure your crossover with Holm Impulse Also see HOW TO: Measure using HOLM and ARTA
Note that I do the time zero locking as per the second link, as this when you measure both drivers from the same point gives the relative phase differences between the drivers. I suspect Paul does this but hasn't got it in his tutorial.
I'm not aware of any tutorials on doing impedance measurements. It is quite easy with a small jig and REW software (or ARTA) Perhaps it is time I did a blog entry on how to do it 😉
Tony.
Note that I do the time zero locking as per the second link, as this when you measure both drivers from the same point gives the relative phase differences between the drivers. I suspect Paul does this but hasn't got it in his tutorial.
I'm not aware of any tutorials on doing impedance measurements. It is quite easy with a small jig and REW software (or ARTA) Perhaps it is time I did a blog entry on how to do it 😉
Tony.
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