They don't get reasonable response down to 60Hz, the 100Hz mark is about as low as you'll get with them. But for a fullrange 100Hz-20+kHz is a really nice range, for these do actually go all the way up into the high frequencies and they do so while still retaining good off-axis response.
You can cross them over at say the 60-80Hz mark to limit excursion and they'll still play mighty loud, but you won't get response all the way down there.
You can cross them over at say the 60-80Hz mark to limit excursion and they'll still play mighty loud, but you won't get response all the way down there.
JoeBob's right. I cross them at 100Hz. In the towers they will go lower but not at a respectable volume and crossing to a sub at 100Hz works quite well. For music like jazz or bluegrass they work fine without additional low end support. The port is 1.75" W x 2" D. A BDSC is a "baffle diffraction step compensation" network. Here is a good article on the subject. About the center channel:
a failed experiment that led to some good learnin'. I attempted to have a 4 driver horizontal center. The problem is, when you put 4 in a row it starts acting like a line array. (Read Jim Griffin's white paper on near field line arrays. Lots of vertical dispersion with limited horizontal dispersion. One solution was to add 2 more drivers. First at the ends of the array but with a large center to center spread (ok but not great). The current solution is to add 2 driver on top of the array. This is working but I'm wondering if it wouldn't be better to just put two on top of two. Anyway, still working on it. Oh, I also found that 3 along the bottom and 1 on top worked well. In the right cabinet it could look pretty cool too.
a failed experiment that led to some good learnin'. I attempted to have a 4 driver horizontal center. The problem is, when you put 4 in a row it starts acting like a line array. (Read Jim Griffin's white paper on near field line arrays. Lots of vertical dispersion with limited horizontal dispersion. One solution was to add 2 more drivers. First at the ends of the array but with a large center to center spread (ok but not great). The current solution is to add 2 driver on top of the array. This is working but I'm wondering if it wouldn't be better to just put two on top of two. Anyway, still working on it. Oh, I also found that 3 along the bottom and 1 on top worked well. In the right cabinet it could look pretty cool too.
Steve-
Yes, flattered once again. If you remember, you helped me, over the phone, design a very similar speaker. The TL line in mine is tapered to the terminus. For the $$, it's a respectable speaker. I thank once again.
My experience with the TB's is similar, the imaging with only one driver was an eye opening experience, (so to speak).
Once, I had the opportunity to replace the front cubes of a friend's HT system with the single driver boxes, using the Acoustimass bass module for low end reinforcement, and HP filter.
Bear with me here... it dramatically was an improvement. Yes, the TB's are far superior to the cube's drivers and enclosures, but I wonder if the high pass x-over from the Module is higher than the filters on my subs' plate amps, or even the 215Hz highest setting on my active x-over, as it's not quire so dramatic in my shop.
I must admit, I haven't done much experimenting, using active x and the TB's in two or three way design. "Raw" is raving about the 871's used as a tweeter in his recent projects.
So, combined with 'Gingo's 300Hz x-over design, and Raw's tweeter use for them, I'm wondering if anyone's done something like this. Could this be the solution for getting that imaging back using these drivers? Clearly it's somewhat lost, using four or even two drivers.
BTW, once again I'll mention... I prefer a small horn tweeter to reinforce the highs and compensate for lobing with my Nonsuch knockoffs. It adds that cymbal presence, and life to real horns. But the ones I'm using are 20 yrs old and I can't seem to find anything similar. Anyone help me?
I also want to mention that I've built a Stryke 2-way using the SA071 midbass and SA-TW1 and I'm impressed with both the drivers, but this very sweet tweeter is nearly choked to death to match it with the 071's efficiency and I'd really like to try a TMMWW using the TBs with the Strykes (Bipole, push-push TL). I'm a good woodworker, but a compleat (sp) electronic and computer moroon. Might this be a good combo?
Anyone want to help me?
Yes, flattered once again. If you remember, you helped me, over the phone, design a very similar speaker. The TL line in mine is tapered to the terminus. For the $$, it's a respectable speaker. I thank once again.
My experience with the TB's is similar, the imaging with only one driver was an eye opening experience, (so to speak).
Once, I had the opportunity to replace the front cubes of a friend's HT system with the single driver boxes, using the Acoustimass bass module for low end reinforcement, and HP filter.
Bear with me here... it dramatically was an improvement. Yes, the TB's are far superior to the cube's drivers and enclosures, but I wonder if the high pass x-over from the Module is higher than the filters on my subs' plate amps, or even the 215Hz highest setting on my active x-over, as it's not quire so dramatic in my shop.
I must admit, I haven't done much experimenting, using active x and the TB's in two or three way design. "Raw" is raving about the 871's used as a tweeter in his recent projects.
So, combined with 'Gingo's 300Hz x-over design, and Raw's tweeter use for them, I'm wondering if anyone's done something like this. Could this be the solution for getting that imaging back using these drivers? Clearly it's somewhat lost, using four or even two drivers.
BTW, once again I'll mention... I prefer a small horn tweeter to reinforce the highs and compensate for lobing with my Nonsuch knockoffs. It adds that cymbal presence, and life to real horns. But the ones I'm using are 20 yrs old and I can't seem to find anything similar. Anyone help me?
I also want to mention that I've built a Stryke 2-way using the SA071 midbass and SA-TW1 and I'm impressed with both the drivers, but this very sweet tweeter is nearly choked to death to match it with the 071's efficiency and I'd really like to try a TMMWW using the TBs with the Strykes (Bipole, push-push TL). I'm a good woodworker, but a compleat (sp) electronic and computer moroon. Might this be a good combo?
Anyone want to help me?
What about the Jordan JX92S?
Hi guys,
Very interesting discussion, and was making me think a lot about what I was thinking of doing. I have a pair of JX92S, and was wondering how it would sound if I built the TL design on the Jordan Website, but added a tweeter. I have lots of questions about my own thoughts/plans:
My musical tastes are totally wide-ranging, and include hard rock, classical, jazz, country, and all kinds of Indian music including classical. I know my design won't give me deep hard rock style bass, but I can add a sub later, I guess.
Thanks and regards,
Tarun
Hi guys,
Very interesting discussion, and was making me think a lot about what I was thinking of doing. I have a pair of JX92S, and was wondering how it would sound if I built the TL design on the Jordan Website, but added a tweeter. I have lots of questions about my own thoughts/plans:
- What tweeter should I use? My budget is USD 50 each (not pair) max.
- I am thinking of XO using LR4 active, at about 3KHz.An earlier thread which used a JX92S and a ribbon tweeter has been excellent food for thought. However, unlike that design, I'm thinking of going for active bi-amping. What do you think?
- Whenever I am tempted to look at TB drivers, their low power rating makes me hesitate. How would my approach work if I used a TB 3" or 4" driver? Would I get high enough SPLs with just one TB driver?
- Lastly, I was told by a friend that TLs have bass extension all right, but their bass sounds very slow. "In other words", he said, "they can handle pipe organs beautifully, but can't convey the impact of low bass drums, because they sound slow." I have zero experience with TLs. Is this at all true?
My musical tastes are totally wide-ranging, and include hard rock, classical, jazz, country, and all kinds of Indian music including classical. I know my design won't give me deep hard rock style bass, but I can add a sub later, I guess.
Thanks and regards,
Tarun
Re: What about the Jordan JX92S?
Perhaps you could go higher to get more coherence in the mid-band.tcpip said:
A properly designed and tuned TL shouldn't have this problem. Resonances are a major contributor to slow sounding bass and a good TL should be anti-resonant. However, it's been a while since I played seriously with TLs. Perhaps one of our TL experts can come in here.
Re: Re: What about the Jordan JX92S?
Tarun
You're right. Had occurred to me too. Don't know what frequency I'll finally try with, but I am basically less confident of the Jordan's ability to reach till 4-5K cleanly, than of a dome tweeter to start at 3K. What do you feel about this?7V said:
Interesting. This means that unless I can hear from someone else on this forum who has tried that precise TL design, I'm on my own.
Tarun
Re: Re: Re: What about the Jordan JX92S?
Speaking very personally, when I'm designing I listen to peoples' opinions and advice but then I do what I want. I have a sound in my head and that's what I go for. The whole thing lives and plays in the imagination before it materializes physically. Sometimes I find it's better to be 'on my own'.
Good luck with it - I have a feeling that you'll make a good speaker.
I feel that Ted Jordan has been so keen on ultra-low cone mass that his drivers tend to be less than ideal under break-up. Even so, I would tend to take them up to 5kHz or 6kHz. Suggest you start at 6kHz then, if you feel improvement would be made, lower the frequency.tcpip said:
It's not so bad. Plenty of people have built the JX92 TL. Surf around on the Internet and you'll find whatever you need to know.This means that unless I can hear from someone else on this forum who has tried that precise TL design, I'm on my own.
Speaking very personally, when I'm designing I listen to peoples' opinions and advice but then I do what I want. I have a sound in my head and that's what I go for. The whole thing lives and plays in the imagination before it materializes physically. Sometimes I find it's better to be 'on my own'.
Good luck with it - I have a feeling that you'll make a good speaker.
>You're right. Had occurred to me too. Don't know what frequency I'll finally try with, but I am basically less confident of the Jordan's ability to reach till 4-5K cleanly, than of a dome tweeter to start at 3K. What do you feel about this?
====
Based on this FR plot: http://www.ejjordan.co.uk/JX92-graphs.html it should be good for a 4kHz/2nd order XO.
WRT TLs, they have to be stuffed so much that they are basically aperiodic, mimicing an IB, which can severely overdamp drivers that rely heavily on its diaphragm TL properties to get wide BW like the Jordan does. An ML-TL OTOH yields more cab efficiency, something the low efficiency JX92S needs in spades. I know a couple of folks who are very pleased with this one where Vb = Vas and F3 = Fs (assuming SS driven):
L = 31.04"
width/depth = 6.97"w x 4.31"d
driver down from top = 11.14"
vent = 2"dia x 5"L
stuffing = 0.54lb
Since the driver will be well below ear height when seated, extending the pipe down the appropriate amount to get the driver up leaves a nice sized cavity to mass load the cab with kitty litter/sand/whatever. I also recommend a heavy top to further mass load it, as well as a driver brace, such as this tunable one: http://melhuish.org/audio/images/press-screw.gif
HTH,
GM
====
Based on this FR plot: http://www.ejjordan.co.uk/JX92-graphs.html it should be good for a 4kHz/2nd order XO.
WRT TLs, they have to be stuffed so much that they are basically aperiodic, mimicing an IB, which can severely overdamp drivers that rely heavily on its diaphragm TL properties to get wide BW like the Jordan does. An ML-TL OTOH yields more cab efficiency, something the low efficiency JX92S needs in spades. I know a couple of folks who are very pleased with this one where Vb = Vas and F3 = Fs (assuming SS driven):
L = 31.04"
width/depth = 6.97"w x 4.31"d
driver down from top = 11.14"
vent = 2"dia x 5"L
stuffing = 0.54lb
Since the driver will be well below ear height when seated, extending the pipe down the appropriate amount to get the driver up leaves a nice sized cavity to mass load the cab with kitty litter/sand/whatever. I also recommend a heavy top to further mass load it, as well as a driver brace, such as this tunable one: http://melhuish.org/audio/images/press-screw.gif
HTH,
GM
Re: Re: Re: Re: What about the Jordan JX92S?
I'll look some more.
What do you think of GM's suggestion for an ML TL design, BTW? I'm still trying to understand it. I didn't even know what "ML TL" meant till I read GM's post and went hunting through t-linespeakers and quarter-wave.com.
Tarun
Will do this. I don't see any downside at all in following your advice. I'll let you know how it goes.7V said:
Will look. I looked through t-linespeakers but couldn't see any JX92 anywhere in those projects. Everyone seems to have built Fostex or Lowther-based stuff, or else gone for multi-way designs. I was somehow expecting that if the JX92S was popular and its prescription-design TLs had been built, they'd be on t-linspeakers.
I'll look some more. Yes, I guess you can do it, given your experience. I was also amazed reading Lynn Olson's process of fine-tuning the XO for his Ariel, walking around the room with an L-pad in his hand. My speaker designing friends cannot imagine doing such fine-tuning by just listening, and then arriving at something with such a flat, natural response curve. I guess you guys have a different level of experience and sensitivity. Why do you think chaps like me pay such close attention to what you guys say?
What do you think of GM's suggestion for an ML TL design, BTW? I'm still trying to understand it. I didn't even know what "ML TL" meant till I read GM's post and went hunting through t-linespeakers and quarter-wave.com.
Thanks. I'll need all the good wishes I can get.
Tarun
The alternate ML TL design
Thanks a lot.
Tarun
Yes, the FR is impressive, but I was worried about cone breakup. I am told that cone breakup with this driver starts at pretty much the same frequencies expected from any 4" aluminium cone. But then I guess 4K or even 5-6K may be okay.GM said:
Sorry, but I didn't even know the full form of "ML TL" till this morning. This "ML TL" seems to be a very interesting idea, confusingly similar to a bass reflex.
How does the "SS driven" make a difference?
When you say "driver down from top", is this the centre of the driver, down from the inner surface of the top wall of the box? And can you explain the "0.54 pounds" for stuffing? I'm sorry to sound daft, but I'm totally new to TL terminology. Does this mean that I put 0.54 lb of Dacron? If yes, where?
Thanks a lot.
Tarun
>Yes, the FR is impressive, but I was worried about cone breakup. I am told that cone breakup with this driver starts at pretty much the same frequencies expected from any 4" aluminium cone. But then I guess 4K or even 5-6K may be okay.
====
This driver doesn't suffer from it, at least in the audible range, but between beaming and a rising on axis response due to its TL properties, 4kHz is a good point to XO at from a purely technical POV.
====
>Sorry, but I didn't even know the full form of "ML TL" till this morning. This "ML TL" seems to be a very interesting idea, confusingly similar to a bass reflex.
====
For decades they were known as tower, or column, designs, and my preferred cab design if not horn loaded. MJK's research into stuffing effects in TLs led him to develop a very accurate worksheet that's adjustable enough to model the results of them, calling it a MLTQWT (mass loaded tuned quarter wavelength tube). Since a TQWT can also define a TL (transmission line), I've gotten in the habit of calling them ML-TLs.
Anyway, a BR morphs into a mass loaded (the vent) 1/4WL resonator (the cab) as the height:width aspect ratio increases. As this occurs, the positioning of the driver and vent become increasingly more important for the best overall performance over the cab's BW. All BR box calculators assume a uniform particle density so their vent calcs are only ~accurate if the cab is built to a golden or acoustic ratio. Also, with increasing pipe action, the vent requirements change, rendering the standard BR vent calcs much too long.
====
>How does the "SS driven" make a difference?
====
SS amps have such a low output impedance (damping factor) that the effect on the driver's Qes/Qts are negligible unless they are powerful enough to drive the speaker into thermal distortion. Tube amps OTOH have considerable output impedance (~2.5-4ohms or more) so Qes/Qts can go up dramatically, increasing the cab Vb/lowering Fb required to keep it from being underdamped (boomy).
====
>When you say "driver down from top", is this the centre of the driver, down from the inner surface of the top wall of the box?
====
Correct.
====
> And can you explain the "0.54 pounds" for stuffing? I'm sorry to sound daft, but I'm totally new to TL terminology. Does this mean that I put 0.54 lb of Dacron? If yes, where?
====
Right, 0.54*16 = ~8.64oz. You want some behind the driver to keep mids/HF reflections from audibly modulating the cone, then spread what's left over between the driver and top of the cab. This quantity is just a suggestion from a sim so you may want to experiment with more/less or different material. FWIW, I prefer acoustic rated fiberglass like is found on insulated suspended ceiling tiles for when only a lining is required, and R-19 wall/attic insulation for stuffing.
====
>Thanks a lot.
Tarun
====
You're welcome!
HTH,
GM
====
This driver doesn't suffer from it, at least in the audible range, but between beaming and a rising on axis response due to its TL properties, 4kHz is a good point to XO at from a purely technical POV.
====
>Sorry, but I didn't even know the full form of "ML TL" till this morning. This "ML TL" seems to be a very interesting idea, confusingly similar to a bass reflex.
====
For decades they were known as tower, or column, designs, and my preferred cab design if not horn loaded. MJK's research into stuffing effects in TLs led him to develop a very accurate worksheet that's adjustable enough to model the results of them, calling it a MLTQWT (mass loaded tuned quarter wavelength tube). Since a TQWT can also define a TL (transmission line), I've gotten in the habit of calling them ML-TLs.
Anyway, a BR morphs into a mass loaded (the vent) 1/4WL resonator (the cab) as the height:width aspect ratio increases. As this occurs, the positioning of the driver and vent become increasingly more important for the best overall performance over the cab's BW. All BR box calculators assume a uniform particle density so their vent calcs are only ~accurate if the cab is built to a golden or acoustic ratio. Also, with increasing pipe action, the vent requirements change, rendering the standard BR vent calcs much too long.
====
>How does the "SS driven" make a difference?
====
SS amps have such a low output impedance (damping factor) that the effect on the driver's Qes/Qts are negligible unless they are powerful enough to drive the speaker into thermal distortion. Tube amps OTOH have considerable output impedance (~2.5-4ohms or more) so Qes/Qts can go up dramatically, increasing the cab Vb/lowering Fb required to keep it from being underdamped (boomy).
====
>When you say "driver down from top", is this the centre of the driver, down from the inner surface of the top wall of the box?
====
Correct.
====
> And can you explain the "0.54 pounds" for stuffing? I'm sorry to sound daft, but I'm totally new to TL terminology. Does this mean that I put 0.54 lb of Dacron? If yes, where?
====
Right, 0.54*16 = ~8.64oz. You want some behind the driver to keep mids/HF reflections from audibly modulating the cone, then spread what's left over between the driver and top of the cab. This quantity is just a suggestion from a sim so you may want to experiment with more/less or different material. FWIW, I prefer acoustic rated fiberglass like is found on insulated suspended ceiling tiles for when only a lining is required, and R-19 wall/attic insulation for stuffing.
====
>Thanks a lot.
Tarun
====
You're welcome!
HTH,
GM
ML TL idea...
Tell me, where do you think I should place the tweeter? Above the box on a small open baffle, or inside the box as close to the JX92S as possible, as conventional theory dictates? Any suggestions?
Thanks a lot,
Tarun
I thought that the zig-zagging of the frequency response towards the top end was more a result of distortion and cone breakup and resonances and the like. I don't know enough to know whether I was right...GM said:
YES!!!! This has been my theory too, ever since I read Lynn Olson's Ariel pages where he said that only valve amps seem to sound good with the Ariel. Basically, I suspect he's designed his crossover completely taking for granted that the source impedance (i.e. the amp's output impedance) is of the kind that valve amps give you. That must be throwing the crossover off balance when faced with a very-low-Z SS amp. Does this make sense? Does this mean that most speakers with passive XOs are either going to give off their best with SS or valve but not both?
I was thinking of putting a stiffer vibration-absorbing sheet or pad on the inner rear wall, directly behind the driver, to absorb as much as possible of the rear wave. Something like a homegrown composite-sandwich version of a Deflex pad (I can't buy those in India). Do you think something like that would help?
Actually, this has been very interesting. I can't even begin to design a TL, but since you've given me pretty much all details, and the construction is simple, I'm really going to try building one to see how it turns out. I'd have built the TL design on the Jordan site, but your design has a simpler construction, and that's appealing. Then later, if I have any money left over after paying the mortgage on the apartment, I may try building the Jordan "official" TL.
Tell me, where do you think I should place the tweeter? Above the box on a small open baffle, or inside the box as close to the JX92S as possible, as conventional theory dictates? Any suggestions?
Thanks a lot,
Tarun
Do I let the Jordan go down full-depth?
Dear GM and Steve (7V),
I've also been thinking of adding a low woofer (say, 150Hz and below) to the Jordan based design someday. If I do this, do you feel it's a good idea to let the Jordan go down to its lowest frequency and roll off on its own, or should I add a high-pass and roll it off a bit earlier?
My doubt stems from the suspicion that the really low frequencies (last three octaves, specially) make the cone move without getting much audible output from a driver like the Jordan (or the Bandor for that matter). In that case, they add to heating, distortion at higher frequencies (harmonics, who knows?) and muddy the midband. Therefore, I thought that a sharp cutoff at, say, 200Hz is a good idea; it'll "free up" the full range to do what it does best, and remove the inaudible overload from it. Of course, I'm thinking active line-level XO, so the problems of low-frequency passive speaker-level XOs will not be there.
The Jordan Website advocates letting the JX92S roll off on its own, and bringing the woofer in using a first-order low-pass. I don't even like this idea, because this will mean that the woofer will remain audible even within the human-voice range, e.g. even at 400Hz. Most large woofers may not be the ideal drivers at those frequencies. I'd prefer a sharper low-pass slope for the woofer.
Do you feel my concerns are justified? Please remember, I know next to nothing about speaker designing. Really.
Thanks and regards,
Tarun
Dear GM and Steve (7V),
I've also been thinking of adding a low woofer (say, 150Hz and below) to the Jordan based design someday. If I do this, do you feel it's a good idea to let the Jordan go down to its lowest frequency and roll off on its own, or should I add a high-pass and roll it off a bit earlier?
My doubt stems from the suspicion that the really low frequencies (last three octaves, specially) make the cone move without getting much audible output from a driver like the Jordan (or the Bandor for that matter). In that case, they add to heating, distortion at higher frequencies (harmonics, who knows?) and muddy the midband. Therefore, I thought that a sharp cutoff at, say, 200Hz is a good idea; it'll "free up" the full range to do what it does best, and remove the inaudible overload from it. Of course, I'm thinking active line-level XO, so the problems of low-frequency passive speaker-level XOs will not be there.
The Jordan Website advocates letting the JX92S roll off on its own, and bringing the woofer in using a first-order low-pass. I don't even like this idea, because this will mean that the woofer will remain audible even within the human-voice range, e.g. even at 400Hz. Most large woofers may not be the ideal drivers at those frequencies. I'd prefer a sharper low-pass slope for the woofer.
Do you feel my concerns are justified? Please remember, I know next to nothing about speaker designing. Really.
Thanks and regards,
Tarun
Re: Do I let the Jordan go down full-depth?
You could certainly add a subwoofer at a later date, although phase matching to a TL bass could be interesting.
I agree with you that a sharper roll-off is probably a good thing for a sub. As for whether and how you filter the main speakers, that's your shout. Try different combinations. There are no rights and wrongs here - just different compromises.
Get playing, Tarun. You may think you know next to nothing about speaker designing now. That will change.
You could certainly add a subwoofer at a later date, although phase matching to a TL bass could be interesting.
I agree with you that a sharper roll-off is probably a good thing for a sub. As for whether and how you filter the main speakers, that's your shout. Try different combinations. There are no rights and wrongs here - just different compromises.
Get playing, Tarun. You may think you know next to nothing about speaker designing now. That will change.
Re: Re: Do I let the Jordan go down full-depth?
BTW, Steve, how do you interface your Nonsuch Bandors to your subs? If you'd rather not discuss details, then please accept my apologies and ignore my question.
Thanks again and regards,
Tarun
As before, thanks for the inputs. And you're right... I need to build something with these ideas. I have now decided... I'm going to start by building that ML TL design, simply because it's a simple box. (Thanks a ton, GM.)7V said:
BTW, Steve, how do you interface your Nonsuch Bandors to your subs? If you'd rather not discuss details, then please accept my apologies and ignore my question.
Thanks again and regards,
Tarun
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