Hi Folks,
New here and my first post so be gentle please...
I'm looking at building a 2-way in a small ported box from resinated bamboo, just under 7.5l (0.26cu ft) using the following;
Vifa XT25TG30, here... https://www.wagneronline.com.au/attachments/Audio-Speakers-PA/vifa/XT25TG30-04.pdf
Dayton RS125-4, here... RS125-4 5" Reference Woofer 4 Ohm Specification Sheethttp://www.daytonaudio.com/specs/specsheet.php?prod=295-370
I've been reading up on crossovers and DIY builds and cramming as much as I can in so at least I can make a descent fist of things. I wanted at least a basic understanding (orientation?) before I came on here asking for advice. I did search these forums for answers but it looks like many take a different approach and/or the threads rambled on and on...
Anyway, obviously I'm looking to keep things reasonably simple for my first build so was thinking 1st Order Butterworth crossed @ 3000Hz. I figure it's a starting point of a plan at the very least.
I've been looking at this website; http://www.geocities.ws/jonrisch/LBIseries.htm
Unfortunately many of the links to his discussions on the subject are broken and while I follow much of his text I still have a few questions regarding this approach. Needless to say he does a good job of laying things out methodically which has helped me immensely and along with this site has got me to where I am.
Anyway, better to keep this short and in light of not knowing the implications of the questions I'm about to ask, I'd better make a start...
1. It appears to me that 3000Hz is the point to cross or am I neglecting other aspects that I need to take into consideration?
2. Looking at Jon's website Figure D looks like what I need. However there is no mention of how to determine the component values... would the values for a series wired setup be the same as those for speakers wired in parallel? At a guess I'd say not, but if they are then I suppose I have even more questions than I first thought.
Anyway thank you in advance for reading and any replies that may result. Hopefully with some assistance I can make a start and further get my head into crossover mayhem
cheers,
Dennis
New here and my first post so be gentle please...
I'm looking at building a 2-way in a small ported box from resinated bamboo, just under 7.5l (0.26cu ft) using the following;
Vifa XT25TG30, here... https://www.wagneronline.com.au/attachments/Audio-Speakers-PA/vifa/XT25TG30-04.pdf
Dayton RS125-4, here... RS125-4 5" Reference Woofer 4 Ohm Specification Sheethttp://www.daytonaudio.com/specs/specsheet.php?prod=295-370
I've been reading up on crossovers and DIY builds and cramming as much as I can in so at least I can make a descent fist of things. I wanted at least a basic understanding (orientation?) before I came on here asking for advice. I did search these forums for answers but it looks like many take a different approach and/or the threads rambled on and on...
Anyway, obviously I'm looking to keep things reasonably simple for my first build so was thinking 1st Order Butterworth crossed @ 3000Hz. I figure it's a starting point of a plan at the very least.
I've been looking at this website; http://www.geocities.ws/jonrisch/LBIseries.htm
Unfortunately many of the links to his discussions on the subject are broken and while I follow much of his text I still have a few questions regarding this approach. Needless to say he does a good job of laying things out methodically which has helped me immensely and along with this site has got me to where I am.
Anyway, better to keep this short and in light of not knowing the implications of the questions I'm about to ask, I'd better make a start...
1. It appears to me that 3000Hz is the point to cross or am I neglecting other aspects that I need to take into consideration?
2. Looking at Jon's website Figure D looks like what I need. However there is no mention of how to determine the component values... would the values for a series wired setup be the same as those for speakers wired in parallel? At a guess I'd say not, but if they are then I suppose I have even more questions than I first thought.
Anyway thank you in advance for reading and any replies that may result. Hopefully with some assistance I can make a start and further get my head into crossover mayhem
cheers,
Dennis
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Most times series values are not the same as parallel values especially once you start to add in CR networks etc. 3000Hz xo point is reasonable on these drivers.
The XT25 is not a good candidate for 6dB filters and needs much higher order filters. It's not the easiest of tweeters to work with but can shine when done correctly.
Have a look at Troels site for some guidance.
DIY-Loudspeakers
The XT25 is not a good candidate for 6dB filters and needs much higher order filters. It's not the easiest of tweeters to work with but can shine when done correctly.
Have a look at Troels site for some guidance.
DIY-Loudspeakers
Rajkom... Is there any BSC in there?
One of the most important things with a 7.5L enclosure is controlling edge diffraction. Use a good thick baffle (I think I used 36mm - two layers of 18mm mdf on mine) then you can sand/saw angled edges in to break down diffraction. If you don't your FR will always be ragged.
Apart from that it looks like a basic xo has been done for you. Make sure you get a basic measurement mic andake a jig to measure impedance or you'll be up against it. As soon as you can measure what you're doing things can get good. Until then, it's just another speaker.
One of the most important things with a 7.5L enclosure is controlling edge diffraction. Use a good thick baffle (I think I used 36mm - two layers of 18mm mdf on mine) then you can sand/saw angled edges in to break down diffraction. If you don't your FR will always be ragged.
Apart from that it looks like a basic xo has been done for you. Make sure you get a basic measurement mic andake a jig to measure impedance or you'll be up against it. As soon as you can measure what you're doing things can get good. Until then, it's just another speaker.
Thank you everyone for your replies. I appreciate that this topic and this situation must become somewhat tiresome for many on here...
I've edited my first post to include the website on series crossovers I have been contemplating. Apologies for missing that...
On the topic of more info, I have scoured my bookmarks and found a little more info on Jon Risch's circuit here Audio Asylum Thread Printer
I note that with respect to component values he says; "Component values are calculated just like standard parallel crossovers for a normal type of crossover."
If I understand what he is doing here correctly, he's using a zobel on woofer (and suggests a zobel possibly for tweeter also ) and then calculates crossover C and L values. Fig D (linked in the first post) also shows tweeter attenuation L and R, but as this is placed before the 'series network' the only consequence of the attenuation pad is overall circuit impedance. It appears he then in later circuit refinements goes on to address the rise impedance.
Have I got the jist of this right? Phew!
Would you be kind enough to elaborate why?
@RajkoM
Wow!
Thank you very much! I wasn't expecting a circuit... however 25L though is a little bigger than the plan I had ATM. Drivers have not been purchased as yet so I'm not bound. Re: BSC I appreciate the input @nannoo but I'm still several steps behind contemplating a basic crossover I understand BSC would need to be addressed possibly in the XO though.
Placement? Likely atop stands 1m from side walls and 1-1.5m from rear nearfield listening. Either rounded/angle corners.
cheers
I've edited my first post to include the website on series crossovers I have been contemplating. Apologies for missing that...
On the topic of more info, I have scoured my bookmarks and found a little more info on Jon Risch's circuit here Audio Asylum Thread Printer
I note that with respect to component values he says; "Component values are calculated just like standard parallel crossovers for a normal type of crossover."
If I understand what he is doing here correctly, he's using a zobel on woofer (and suggests a zobel possibly for tweeter also ) and then calculates crossover C and L values. Fig D (linked in the first post) also shows tweeter attenuation L and R, but as this is placed before the 'series network' the only consequence of the attenuation pad is overall circuit impedance. It appears he then in later circuit refinements goes on to address the rise impedance.
Have I got the jist of this right? Phew!
Rabbitz said:
Would you be kind enough to elaborate why?
@RajkoM
Wow!
Thank you very much! I wasn't expecting a circuit... however 25L though is a little bigger than the plan I had ATM. Drivers have not been purchased as yet so I'm not bound. Re: BSC I appreciate the input @nannoo but I'm still several steps behind contemplating a basic crossover
I understand BSC would need to be addressed possibly in the XO though. Placement? Likely atop stands 1m from side walls and 1-1.5m from rear nearfield listening. Either rounded/angle corners.
cheers
Ok, would this driver be a better match with the XT25 for around 7.5L volume?
https://www.wagneronline.com.au/attachments/Audio-Speakers-PA/dayton/PS95-8.pdf
https://www.wagneronline.com.au/attachments/Audio-Speakers-PA/dayton/PS95-8.pdf
Very few tweeters can handle 6dB xo's and those that can are crossed over quite high. I suggest you get the Loudspeaker Design Cookbook by Vance Dickson to get an understanding of loudspeaker design if you are going to continue in this hobby. Picking up bits of information around the web is not going to be very useful.
To elaborate a bit more and especially on the XT25 have a look at this.
Zaph|Audio - ZD5 - Scan Speak 15W8530K00 and Vifa XT25
If you only want a pair of speakers to build and use, I suggest a proven design such as Geoff Bagby's Soprano which is a great 4" design.
If you do want to continue with self design as a hobby, then be prepared for a lot of cost and heartburn but it can be very rewarding.
BTW, there are a lot of good commercial bargains out there and I picked up some new Q Acoustics for less than I can buy drivers and parts even at my wholesale prices.
To elaborate a bit more and especially on the XT25 have a look at this.
Zaph|Audio - ZD5 - Scan Speak 15W8530K00 and Vifa XT25
If you only want a pair of speakers to build and use, I suggest a proven design such as Geoff Bagby's Soprano which is a great 4" design.
If you do want to continue with self design as a hobby, then be prepared for a lot of cost and heartburn but it can be very rewarding.
BTW, there are a lot of good commercial bargains out there and I picked up some new Q Acoustics for less than I can buy drivers and parts even at my wholesale prices.
Thanks rabbitz for your comments and the links
Reading Zaph however has only confused me further. It seems the issue he finds with the XT25 is the alignment of acoustic centres. He seems to have a method though... However this leads me back to inquiring about 1st order xover's in particular... that phase coherence is more important across all F, not just at the xo point. Also, the very characteristic for drivers suitable for use in (his at least) LR2 xo seems to be the very same for 1st order...
The last part of the quote is I suppose why I inquired about 1st order initially: ...sounds better... but much, much more than an LC circuit.
Regarding phase and time alignment, Rod Elliott seems to have a very different view as I read things... http://sound.whsites.net/ptd.htm
I don't wish to sound argumentative here... apologies if my comments read that way.
I guess I need to establish one position here and make a start. Whether that's a series or parallel xo to begin with, (right or wrongly). As RajkoM has very kindly gone to the trouble of providing a schematic of a parallel xo that seems to be the logical starting place for me. Happy to do the DIY thing over plans or commercial offerings as I hope this leads to not only a build to be proud of but an education of sorts as well.
Many thanks again.
Reading Zaph however has only confused me further. It seems the issue he finds with the XT25 is the alignment of acoustic centres. He seems to have a method though... However this leads me back to inquiring about 1st order xover's in particular... that phase coherence is more important across all F, not just at the xo point. Also, the very characteristic for drivers suitable for use in (his at least) LR2 xo seems to be the very same for 1st order...
The last part of the quote is I suppose why I inquired about 1st order initially: ...sounds better... but much, much more than an LC circuit.
Regarding phase and time alignment, Rod Elliott seems to have a very different view as I read things... http://sound.whsites.net/ptd.htm
I don't wish to sound argumentative here... apologies if my comments read that way.
I guess I need to establish one position here and make a start. Whether that's a series or parallel xo to begin with, (right or wrongly). As RajkoM has very kindly gone to the trouble of providing a schematic of a parallel xo that seems to be the logical starting place for me. Happy to do the DIY thing over plans or commercial offerings as I hope this leads to not only a build to be proud of but an education of sorts as well.
Many thanks again.
That tweeter has poor distortion performance below 2500 hz if memory serves. I've used it with a 24dB/octave slope @ 3khz and it worked pretty good to my ears. 6dB/octave at 3khz means it will be 6db down at 1500Hz and only 12dB down at 750Hz..... Whereas 24dB/octave will be 24 dB down at 1.5khz and 48dB down@ 750Hz. Huge difference in how much low frequencies content goes to the tweeter
Series xo's generally require well behaved drivers as correction circuits can hard to implement in these crossovers as they tend to effect both drivers. Even a CR on the woofer and cause issues with the tweeter response. Most of my speaker designs are series either classic or AR series as I find them easier to design and tweak. Others such as the last speaker I did are parallel crossovers as they were not good candidates for series.
I won't get into the sound difference debate as there are plenty of threads here on that subject.
I won't get into the sound difference debate as there are plenty of threads here on that subject.
Cheers rabbitz.
Thanks for the link Pete, one can hardly argue with analysis series v parallel
measured findings.
@AllenB... I read your thread "Introduction to designing crossovers without measurement". A lot to take in...
I'm more than happy to go with the crossover provided by RajkoM for the build but I don't understand it... parallel obviously but what type? Does it need a Zobel or is that factored in somehow already?
Thanks for the link Pete, one can hardly argue with analysis series v parallel
measured findings.
@AllenB... I read your thread "Introduction to designing crossovers without measurement". A lot to take in...
I'm more than happy to go with the crossover provided by RajkoM for the build but I don't understand it... parallel obviously but what type? Does it need a Zobel or is that factored in somehow already?
I think the XT25TG30 is excellent for a SXO. I used the same drivers as Zaph's ZD5 in my own project called 'Scandivifias' at about the same time, and used a SXO and they sound very good.
If you are looking for a good kit using the RS125-4, my Stance design is few in parts, and uses the Beston RT003C along with it.
Later,
Wolf
If you are looking for a good kit using the RS125-4, my Stance design is few in parts, and uses the Beston RT003C along with it.
Later,
Wolf
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