Recommended XO parts?
First I little background, skip to the question below if you like.
For the past year or so, I use a single 4uF cap and inductor (value unknown) for my JX92s\G2si XO in triangular 48" cabinets with 10" baffle. (Cabs were made for me by member Chrisb)
I use two amp channels per speaker so that I can match the volume levels on the two drivers before amplification.
I enjoy the sound very much, very clean sound because of the small amount of parts in the signal path. I can not achieve high sound levels because of the 6db XO slope. The tweeter begins to distorts at higher volume as you would expect. It goes loud enough for me.
The main reason I use this simple XO was the low cost and I like to experiment. Now I am ready to try Jims XO to learn more and hopefully in the process take the sound quality even higher.
~~~~~~~~~
Question: What parts do you guys recommend or use yourself in this XO? I know selection of audio parts is subjective to personal tastes like food and size of wallet. I am interested to know as a starting point and to benefit from your experience.
For the resistors:
I have already purchased Mills 12W resistors. The cost is something like $3.50 each. 6 are required for a pair of XOs.
For caps:
I have purchased Solen Fast Caps as a starting point. The cost averages at $4 per cap. 6 are required for a pair of XOs. A local speaker manufacturer recommends Sonicap bypass caps on all the Solen caps. Sonicap II or Platinum, the later being the more expensive. The Sonicaps bypass caps adds approx. $22 to $195 for the pair of XOs.
For inductors:
I was thinking Solen Air Cored Coils.
Comments? What do you use/recommend and why?
Jim, I read your post about trying larger values then 1.5mH to compensate for the wider baffle and I will try that at after I get used to 1.5mH.
First I little background, skip to the question below if you like.
For the past year or so, I use a single 4uF cap and inductor (value unknown) for my JX92s\G2si XO in triangular 48" cabinets with 10" baffle. (Cabs were made for me by member Chrisb)
I use two amp channels per speaker so that I can match the volume levels on the two drivers before amplification.
I enjoy the sound very much, very clean sound because of the small amount of parts in the signal path. I can not achieve high sound levels because of the 6db XO slope. The tweeter begins to distorts at higher volume as you would expect. It goes loud enough for me.
The main reason I use this simple XO was the low cost and I like to experiment. Now I am ready to try Jims XO to learn more and hopefully in the process take the sound quality even higher.
~~~~~~~~~
Question: What parts do you guys recommend or use yourself in this XO? I know selection of audio parts is subjective to personal tastes like food and size of wallet. I am interested to know as a starting point and to benefit from your experience.
For the resistors:
I have already purchased Mills 12W resistors. The cost is something like $3.50 each. 6 are required for a pair of XOs.
For caps:
I have purchased Solen Fast Caps as a starting point. The cost averages at $4 per cap. 6 are required for a pair of XOs. A local speaker manufacturer recommends Sonicap bypass caps on all the Solen caps. Sonicap II or Platinum, the later being the more expensive. The Sonicaps bypass caps adds approx. $22 to $195 for the pair of XOs.
For inductors:
I was thinking Solen Air Cored Coils.
Comments? What do you use/recommend and why?
Jim, I read your post about trying larger values then 1.5mH to compensate for the wider baffle and I will try that at after I get used to 1.5mH.
I have the 48" MLTL with Fountek NeoCD3 tweeter in a small room with stone walls (~40Hz and ~60Hz room resonances) and the bass is totally fine in most situations when listening in the middle of the room. In the back corners some boominess can be heard though, but I'm never there so doesn't matter.Colin said:
I'm looking to build this speaker using triangular 48" cabinets. I have a couple questions that I hope people can help with.
Will the triangular cabinets be better than the standard design, I understand about reduced reflections (which should be good), but has anyone actually compared them?
From what I've read I understand the G2si isn't shielded. I'll need to place one of the speakers near (12") a CRT TV. Can anyone confirm if they are shielded, and if not, will this going to cause problems with the TV picture at that distance?
In an earlier post Keladrin asked if there's any UK suppliers. I've searched but can't find an importer. Does anyone know if there is an importer or someone that will ship to the UK.
Dave
Will the triangular cabinets be better than the standard design, I understand about reduced reflections (which should be good), but has anyone actually compared them?
From what I've read I understand the G2si isn't shielded. I'll need to place one of the speakers near (12") a CRT TV. Can anyone confirm if they are shielded, and if not, will this going to cause problems with the TV picture at that distance?
In an earlier post Keladrin asked if there's any UK suppliers. I've searched but can't find an importer. Does anyone know if there is an importer or someone that will ship to the UK.
Dave
Re: Recommended XO parts?
Brent - it sounds like you got the installation of the ribbons taken care of - I'd suggest that since it sounds like you might be dialing the XO's in for a while yet, go with the cheaper Solen film caps 'til you get their values and the inductors figured out.
Out of curiosity, which local speaker manufacturer recommending bypassing all the Solen caps before you actually lived with the completed system for a few dozen hours? While it's certainly not likely to hurt, they might sound quite fine without, and you might well be able to save a couple of hundred bucks.
As for the chokes, without researching Jim's XO design, the only comment I could make is that in some cases ferrite core inductors have well have specific technical advantages over air core (lower DCR may be critical to the application), and with the cost of copper not likely to decline anytime soon, lower price never hurts
Brent Welke said:
Brent - it sounds like you got the installation of the ribbons taken care of - I'd suggest that since it sounds like you might be dialing the XO's in for a while yet, go with the cheaper Solen film caps 'til you get their values and the inductors figured out.
Out of curiosity, which local speaker manufacturer recommending bypassing all the Solen caps before you actually lived with the completed system for a few dozen hours? While it's certainly not likely to hurt, they might sound quite fine without, and you might well be able to save a couple of hundred bucks.
As for the chokes, without researching Jim's XO design, the only comment I could make is that in some cases ferrite core inductors have well have specific technical advantages over air core (lower DCR may be critical to the application), and with the cost of copper not likely to decline anytime soon, lower price never hurts
Will the triangular cabinets be better than the standard design, I understand about reduced reflections (which should be good), but has anyone actually compared them?
I built my design with a rectangular cabinet so all of the measurements and design detail was done with that design. If you use the triangular cabinet, I would suggest that you maintain the same baffle width that I used so that the baffle step compensation inherent within the crossover would be applicable.
From what I've read I understand the G2si isn't shielded. I'll need to place one of the speakers near (12") a CRT TV. Can anyone confirm if they are shielded, and if not, will this going to cause problems with the TV picture at that distance?
The G2si is effectively shielded. The only issue is the gap down the center of the tweeter where the ribbon hangs. Hnce, a screw or steel object would be attracted to the screen grid that covers this area. This is not a concern with your application.
I'm not much help on distributors for these Aurum Cantus drivers in Europe. Creative Sounds in Canada (www.creativesound.ca) could ship to you but I suspect you can find a closer supplier.
Jim
I built my design with a rectangular cabinet so all of the measurements and design detail was done with that design. If you use the triangular cabinet, I would suggest that you maintain the same baffle width that I used so that the baffle step compensation inherent within the crossover would be applicable.
From what I've read I understand the G2si isn't shielded. I'll need to place one of the speakers near (12") a CRT TV. Can anyone confirm if they are shielded, and if not, will this going to cause problems with the TV picture at that distance?
The G2si is effectively shielded. The only issue is the gap down the center of the tweeter where the ribbon hangs. Hnce, a screw or steel object would be attracted to the screen grid that covers this area. This is not a concern with your application.
I'm not much help on distributors for these Aurum Cantus drivers in Europe. Creative Sounds in Canada (www.creativesound.ca) could ship to you but I suspect you can find a closer supplier.
Jim
Port location, bracing, baffle edge, and "stuffing"?
Dear Mr. Griffin,
The MLTL-48 design on the http://www.ejjordan.co.uk/diy/ web site shows the port being in the front, while I believe the picture of your speakers in post #1 of this tread shows your's on the back. Why was this done, and what impact does this have on the design?
Did you put any bracing in your cabinets? If so, how many, where, and general shape please?
On your monitors, you rounded the outer edges of the 7.5 inch wide front baffle at 1/2 or 3/4 inch. Did you also do this with these speakers?
Also, what type and amount of "stuffing" did you use, along with where did you locate it ( .54 lbs at the top, as shown in the above link? )?
Thank you for your sharing your designs with us!
Tom
Dear Mr. Griffin,
The MLTL-48 design on the http://www.ejjordan.co.uk/diy/ web site shows the port being in the front, while I believe the picture of your speakers in post #1 of this tread shows your's on the back. Why was this done, and what impact does this have on the design?
Did you put any bracing in your cabinets? If so, how many, where, and general shape please?
On your monitors, you rounded the outer edges of the 7.5 inch wide front baffle at 1/2 or 3/4 inch. Did you also do this with these speakers?
Also, what type and amount of "stuffing" did you use, along with where did you locate it ( .54 lbs at the top, as shown in the above link? )?
Thank you for your sharing your designs with us!
Tom
XO results so far
Hi Guys,
I ended up going with Sonicap for all caps with Sonicap Gen II bypass caps for all. The inductors are Solen air core. Mills resistors.
The local speaker builder who supplied the parts is Al Wooly from http://rawacoustics.com/.
I had already ordered Solen caps from partsconnexion but while talking with Al I learned that the 15uF cap would best be built by stacking lower value caps and using even better bypass caps.
He gave me a list of options/upgrades on the parts and I took the second to most expensive option at around $280. I figured I would need almost the best to compete with my current setup. I know the difference a part can make.
The parts arrived on Saturday, I rushed into building the XO right at the speaker
After 1/2 hour I came to my senses and finished building the XO back at my desk.
Finally I compared the two by using one speaker with the new XO and one speaker with the old XO.
The results were not good. The new XO sounded lifeless and muddy. I ran out of time to mess around and went back to using my old XO.
I have not given up but rather now I have to evaluate these parts one at a time to get a feel for them, like spices and cooking. Maybe I made a mistake in my hasty build. I also have Solen caps to work/taste with.
It will probably be a week before I mess with it again. I will continue to post my results here. Chrisb lives close enough to me that I can likely borrow his ears to double check the results.
Cheers,
Brent
Hi Guys,
I ended up going with Sonicap for all caps with Sonicap Gen II bypass caps for all. The inductors are Solen air core. Mills resistors.
The local speaker builder who supplied the parts is Al Wooly from http://rawacoustics.com/.
I had already ordered Solen caps from partsconnexion but while talking with Al I learned that the 15uF cap would best be built by stacking lower value caps and using even better bypass caps.
He gave me a list of options/upgrades on the parts and I took the second to most expensive option at around $280. I figured I would need almost the best to compete with my current setup. I know the difference a part can make.
The parts arrived on Saturday, I rushed into building the XO right at the speaker
After 1/2 hour I came to my senses and finished building the XO back at my desk.Finally I compared the two by using one speaker with the new XO and one speaker with the old XO.
The results were not good. The new XO sounded lifeless and muddy. I ran out of time to mess around and went back to using my old XO.
I have not given up but rather now I have to evaluate these parts one at a time to get a feel for them, like spices and cooking. Maybe I made a mistake in my hasty build. I also have Solen caps to work/taste with.
It will probably be a week before I mess with it again. I will continue to post my results here. Chrisb lives close enough to me that I can likely borrow his ears to double check the results.
Cheers,
Brent
Tom:
Some answers below--
1. The MLTL-48 design on the http://www.ejjordan.co.uk/diy/ web site shows the port being in the front, while I believe the picture of your speakers in post #1 of this tread shows your's on the back. Why was this done, and what impact does this have on the design?
I like rear porting vs. front but it should not matter too much. Duke on Audioasylum has some good reasons to rear port at:
http://www.audioasylum.com/audio/speakers/messages/25/259045.html
2. Did you put any bracing in your cabinets? If so, how many, where, and general shape please?
Yes, I use one windowed (single large diameter hole) brace placed a couple of inches below the woofer cutout. This location is a good place to locate a wire grid to hold the loose stuffing in the upper portion of the box as well.
3. On your monitors, you rounded the outer edges of the 7.5 inch wide front baffle at 1/2 or 3/4 inch. Did you also do this with these speakers?
I also rounded the outer edges of the MLTL.
4. Also, what type and amount of "stuffing" did you use, along with where did you locate it ( .54 lbs at the top, as shown in the above link? )?
I filled the top of the box with teased Acousta Suf brand material.
In my speakers I recently noticed that the glue seam at the top of the enclosure had a few small separations to the side panels. This is a high pressure area and the cracks created noticeable air leaks on bass heavy music. I reglued that seam and recalked the inside seams at the top of the box. I also inserted a pad of Sonic Barrier 3/4" thick dampening material into the inside top of the box. I replaced the loose stuffing between that pad and the wire grid located on top of the brace. That mod seems to have solved my issues.
Jim
Some answers below--
1. The MLTL-48 design on the http://www.ejjordan.co.uk/diy/ web site shows the port being in the front, while I believe the picture of your speakers in post #1 of this tread shows your's on the back. Why was this done, and what impact does this have on the design?
I like rear porting vs. front but it should not matter too much. Duke on Audioasylum has some good reasons to rear port at:
http://www.audioasylum.com/audio/speakers/messages/25/259045.html
2. Did you put any bracing in your cabinets? If so, how many, where, and general shape please?
Yes, I use one windowed (single large diameter hole) brace placed a couple of inches below the woofer cutout. This location is a good place to locate a wire grid to hold the loose stuffing in the upper portion of the box as well.
3. On your monitors, you rounded the outer edges of the 7.5 inch wide front baffle at 1/2 or 3/4 inch. Did you also do this with these speakers?
I also rounded the outer edges of the MLTL.
4. Also, what type and amount of "stuffing" did you use, along with where did you locate it ( .54 lbs at the top, as shown in the above link? )?
I filled the top of the box with teased Acousta Suf brand material.
In my speakers I recently noticed that the glue seam at the top of the enclosure had a few small separations to the side panels. This is a high pressure area and the cracks created noticeable air leaks on bass heavy music. I reglued that seam and recalked the inside seams at the top of the box. I also inserted a pad of Sonic Barrier 3/4" thick dampening material into the inside top of the box. I replaced the loose stuffing between that pad and the wire grid located on top of the brace. That mod seems to have solved my issues.
Jim
Brent:
1) I think the design parameters Al prefers for XO's in his monster line array HT systems, might not translate well to drivers as revealing as the Jordan / ribbon combo, but:
2) you definitely need to get the ribbons actually installed in the boxes before judging integration and final voicing.
3) my "ears" are not calibrated at all - and if you borrow them, 40 yrs of listening prejudices and "taste" are attendant.
4) parts quality /cost is only part of the story
1) I think the design parameters Al prefers for XO's in his monster line array HT systems, might not translate well to drivers as revealing as the Jordan / ribbon combo, but:
2) you definitely need to get the ribbons actually installed in the boxes before judging integration and final voicing.
3) my "ears" are not calibrated at all - and if you borrow them, 40 yrs of listening prejudices and "taste" are attendant.
4) parts quality /cost is only part of the story
Regarding bracing, like Jim I placed a window brace a couple of inches below the driver in my triangular enclosures. When I got the chance recently to run some tones through the speaker, it picked up a panel resonance at 100Hz. I think this is due to the lower sections, so I'd recommend a second window brace somewhere between the first and the base (not half way, try and keep the length of panels between braces dissimilar to spread resonances).
Re: XO results so far
How many hours on the old XO? Do remeber that any active device with a mechanical component in its construction will have some break-in time. Caps in particular. Some of the more exotic ones can take 100s of hours. Put the new XOs back in and let them steam for a week or more. Then compare.
dave
Brent Welke said:
How many hours on the old XO? Do remeber that any active device with a mechanical component in its construction will have some break-in time. Caps in particular. Some of the more exotic ones can take 100s of hours. Put the new XOs back in and let them steam for a week or more. Then compare.
dave
planet10 said:
Greets!
Actually, in a pipe's pressure wave BW it's not an issue as long as their Vb is accounted for in the CSA calculation. Above this point though, standing waves develop, requiring more damping than otherwise, which of course damps some of the pipe action you went to the expense/effort to design in. Worse, you've now created a panel resonance 'hot spot' along its length, so more have to be added to further break up the panel's modes to raise their frequency/reduce their amplitude. That, or do like at least one manufacturer does and line the inside with acoustic tiles to quell higher harmonics via mass loading as well as any parallel wall eigenmodes (standing waves).
So as you note, short of building the pipe out of a material and/or thickness that shifts the panel's resonances either above or below the pipe's total BW, the most efficient bracing is a simple 'ridge' board run along the length of each of the pipe's long panels and spaced at some acoustic ratio between its corner joints. Note that from a purely technical POV these should terminate somewhat short of the various corner joints since it unnecessarily increases these unavoidable 'hot spots', though I've never seen any simple math to calc how much short. Me, I would just grab a suitable piece of scrap (or even several short pieces with gaps between them) that spanned the majority of its length and could never feel any vibration.
Anyway, combining these into a driver mass loading brace (I'm assuming here that it does apply a small amount of positive pressure to the driver to tension it to the baffle or at least is close enough to add thin shims) just further increases mechanical coupling efficiency.
GM
Colin said:
Understood, but this frequency happens to be right around the fundamental 1/4 WL resonance from the driver to the bottom of the pipe based on the build dims you gave me, so just wanted to make sure of where it was coming from. Regardless, per my previous post, adding ridge boards should suffice and is much less labor intensive than adding more window braces.
GM
Hi Greg - Well, I assumed that was what was happening. The vibration was most apparent on the front, lower section of the triangle, where there is no bracing. Possibly it was a combination of effects, particularly as this first test was done without damping in the pipe. I didn't think to try it again once stuffing was added.
The triangles are in store temporarily, once they're up and running again I'll try again. Thanks for the tip about longtitudinal bracing. Just to be clear - is this like a narrow shelf fitted to the panel or are you cross-bracing to the opposite panel (in a rectangular box)?
The triangles are in store temporarily, once they're up and running again I'll try again. Thanks for the tip about longtitudinal bracing. Just to be clear - is this like a narrow shelf fitted to the panel or are you cross-bracing to the opposite panel (in a rectangular box)?
Greets!
Hmm, 'longitude' implies a horizontal plane, but I said along its length, so for a vertically oriented pipe it would be correct to say along its latitude in geographical parlance.
Anyway, I'm referring to just a strip of either no-void ply or similarly rigid material bonded along its length to form a 'T' with the panel. If you want to span one piece between two walls, you can of course, but in a high aspect ratio cab it's normally not necessary until the CSA gets pretty big. An acoustic ratio subwoofer OTOH requires them in most cases so that it can't 'breathe'.
That said, I'm still not convinced you were feeling a panel resonance per se since as MJK has periodically noted, most of the pressure is along its length in high aspect ratio cabs, ergo relatively speaking there's not much acoustic energy to excite the panels except at the top and bottom and why I recommend mass loading them by adding weight to its top, so I'd do this before spending any time installing extra bracing. A nice, heavy potted plant does wonders and very high SAF.
GM
Hmm, 'longitude' implies a horizontal plane, but I said along its length, so for a vertically oriented pipe it would be correct to say along its latitude in geographical parlance.
Anyway, I'm referring to just a strip of either no-void ply or similarly rigid material bonded along its length to form a 'T' with the panel. If you want to span one piece between two walls, you can of course, but in a high aspect ratio cab it's normally not necessary until the CSA gets pretty big. An acoustic ratio subwoofer OTOH requires them in most cases so that it can't 'breathe'.
That said, I'm still not convinced you were feeling a panel resonance per se since as MJK has periodically noted, most of the pressure is along its length in high aspect ratio cabs, ergo relatively speaking there's not much acoustic energy to excite the panels except at the top and bottom and why I recommend mass loading them by adding weight to its top, so I'd do this before spending any time installing extra bracing. A nice, heavy potted plant does wonders and very high SAF.
GM
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