Thanx, lots of useful info there. The Model T drawings need redoing. So i dug out the original CoffinWoofer, tidied it up, and have started on the Model T.
Here is the coffin woofer drawing: https://www.t-linespeakers.org/download/B139CoffinWoofer-260823.pdf
dave
Here is the coffin woofer drawing: https://www.t-linespeakers.org/download/B139CoffinWoofer-260823.pdf
dave
Say, that looks a lot like the 17-foot labyrinth I posted. Still working very well.
https://www.diyaudio.com/forums/subwoofers/322418-17-foot-pipe-sub-12-230-hz-5db.html
BTW, a lot of us have a warm-spot for the unique B139, esp for TLs. But I sure don't know what is actually good about that driver for this purpose, except maybe being narrow and tall? I'd look for a modern driver with more magnet and lower resonance, not one of those clever British compromise solutions on a budget from yesteryear (and I say that as an audiophile who thinks his 1960 Stephens woofer is as good as could be).
B.
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First question is: are you interested in (1) wrangling a basic system to see roughly how it sounds or (2) are you looking for a definitive process leading to a better HiFi system with a passive crossover?
BTW, #2 is not feasible. No way to fashion a passive XO at low frequencies that does much to keep distortion-causing lows out of mid-range and distortion-causing highs out of woofer. And, with the phase twists and turns and the physical separation of the woofer(s) from L and R speakers, no good way to fine-tune at well-behaved frequency response.
With electronic XO, you can have sharp slopes at low frequencies and the shortcomings mentioned in previous paragraph no long apply.
B.
BTW, #2 is not feasible. No way to fashion a passive XO at low frequencies that does much to keep distortion-causing lows out of mid-range and distortion-causing highs out of woofer. And, with the phase twists and turns and the physical separation of the woofer(s) from L and R speakers, no good way to fine-tune at well-behaved frequency response.
With electronic XO, you can have sharp slopes at low frequencies and the shortcomings mentioned in previous paragraph no long apply.
B.
B.
I've been unable to get back here for various reason and I appreciate your input here but I'm at a loss about what you wrote concerning:
"BTW, #2 is not feasible. No way to fashion a passive XO at low frequencies that does much to keep distortion-causing lows out of mid-range and distortion-causing highs out of woofer. And, with the phase twists and turns and the physical separation of the woofer(s) from L and R speakers, no good way to fine-tune at well-behaved frequency response."
About the distortions; Are you referring to that effect on my main speakers? If you are, with the dual channel TL's hooked up in parallel to them ( 8+4=2.7ohms, with my amp stable down to 2ohms) I don't know how your assumption would affect the Xover of the main speakers.
I hooked up the coil as a simple 1st order, low-pass (measured with my cap/ind meter @ 15mh, therefore Xover =84hz) so i imagine phase would not be an issue. I haven't had much time to listen but i believe it definitely needs more gain. There's no question that the lower lows, i was hoping for, are now coming through. I did not notice those distortions you mentioned but then again I haven't had much time to properly listen.
If the distortions you mention, pertain to the dual channel TL's, then I have yet to hear them. probably because they need more volume but on a few select tracks, the deeper lows are most definitely there now.
My ultimate goal is to, if feasible, incorporate my Fried dual channel Woofer TL with my mains. I am willing to do this passively or powering the woofer TL with 2 sub amps or go with the biamping and active Xover route in that order. I would like to achieve the best sound with the least amount of effort and cost but I definitely want to use the coffin before I move on to 2 new active subwoofer units if all else fails and how to do that is the guidance, I so desire from all you good fellas.
So,,,
#1: am i misunderstanding your distortion issue and need to do more listening to confirm and then move on?
#2: If i can't hear those distortions, is there a way to increase the gain on the TL woofers to definitively determine what I hear is good or bad?
I was thinking if i inject pink noise to the speakers and use my spl meter to measure the general output of the mains and then the TL woofers, that would confirm if the TL woofers definitely need more gain?
If I can't get more gain, because it does need more oomph, I'll move on to the subamp plates for the TL woofers. If that's the case, how many watts would you want to properly handle 84hz and down.
I just hate to bypass the main Xovers with an active Xover scenario because the main Xovers were upgraded by a $1000 just in parts and they resolve everything so well and i really dont want to start fiddling with the passive component values to get it right when using the biamping, active Xover route. Thats a lot of time. b4 i can just sit back and relax.
I have a Dyna 416 with the energy banks sitting on the side but id rather use another VanAlstine 400 but ill need to ship it out as my son shorted out the outputs years ago. Its much better sounding and im not looking forward to getting a box to safely ship 50lbs.
Thanks so much for your help,
BTW, I checked out you Stephens woofer but didnt know if it was the 12 or 15".
Interested to read more about it. I have 8 or 9 speaker sets and one I helped build with my dad when i was 12 that he passed along to me. A 15" JBL D130, with the 075 bullets in a beautiful Karlson cab that I later modified the Xover to add an altec 288c with mantarays on top. Talk about bass and dynamics!! Sent the JBL's to CA and had them regaussed, tuned up. so to speak. Efficiency out the wazoo,,,they can blow out windows. Always wanted to hear the paragons as an adult. Heard them with my pop but too young to really appreciate.
I've been unable to get back here for various reason and I appreciate your input here but I'm at a loss about what you wrote concerning:
"BTW, #2 is not feasible. No way to fashion a passive XO at low frequencies that does much to keep distortion-causing lows out of mid-range and distortion-causing highs out of woofer. And, with the phase twists and turns and the physical separation of the woofer(s) from L and R speakers, no good way to fine-tune at well-behaved frequency response."
About the distortions; Are you referring to that effect on my main speakers? If you are, with the dual channel TL's hooked up in parallel to them ( 8+4=2.7ohms, with my amp stable down to 2ohms) I don't know how your assumption would affect the Xover of the main speakers.
I hooked up the coil as a simple 1st order, low-pass (measured with my cap/ind meter @ 15mh, therefore Xover =84hz) so i imagine phase would not be an issue. I haven't had much time to listen but i believe it definitely needs more gain. There's no question that the lower lows, i was hoping for, are now coming through. I did not notice those distortions you mentioned but then again I haven't had much time to properly listen.
If the distortions you mention, pertain to the dual channel TL's, then I have yet to hear them. probably because they need more volume but on a few select tracks, the deeper lows are most definitely there now.
My ultimate goal is to, if feasible, incorporate my Fried dual channel Woofer TL with my mains. I am willing to do this passively or powering the woofer TL with 2 sub amps or go with the biamping and active Xover route in that order. I would like to achieve the best sound with the least amount of effort and cost but I definitely want to use the coffin before I move on to 2 new active subwoofer units if all else fails and how to do that is the guidance, I so desire from all you good fellas.
So,,,
#1: am i misunderstanding your distortion issue and need to do more listening to confirm and then move on?
#2: If i can't hear those distortions, is there a way to increase the gain on the TL woofers to definitively determine what I hear is good or bad?
I was thinking if i inject pink noise to the speakers and use my spl meter to measure the general output of the mains and then the TL woofers, that would confirm if the TL woofers definitely need more gain?
If I can't get more gain, because it does need more oomph, I'll move on to the subamp plates for the TL woofers. If that's the case, how many watts would you want to properly handle 84hz and down.
I just hate to bypass the main Xovers with an active Xover scenario because the main Xovers were upgraded by a $1000 just in parts and they resolve everything so well and i really dont want to start fiddling with the passive component values to get it right when using the biamping, active Xover route. Thats a lot of time. b4 i can just sit back and relax.
I have a Dyna 416 with the energy banks sitting on the side but id rather use another VanAlstine 400 but ill need to ship it out as my son shorted out the outputs years ago. Its much better sounding and im not looking forward to getting a box to safely ship 50lbs.
Thanks so much for your help,
BTW, I checked out you Stephens woofer but didnt know if it was the 12 or 15".
Interested to read more about it. I have 8 or 9 speaker sets and one I helped build with my dad when i was 12 that he passed along to me. A 15" JBL D130, with the 075 bullets in a beautiful Karlson cab that I later modified the Xover to add an altec 288c with mantarays on top. Talk about bass and dynamics!! Sent the JBL's to CA and had them regaussed, tuned up. so to speak. Efficiency out the wazoo,,,they can blow out windows. Always wanted to hear the paragons as an adult. Heard them with my pop but too young to really appreciate.
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The world is full of speakers that some listener thinks is very satisfying and yet there might be nothing but a single capacitor in the enclosure and doing not much more than keeping bass from destroying the upper drivers; that can be OK, esp for woofers that have wide ranges and treble that comes in only at high frequencies.
(a) I believe that putting excessive bass or excessive treble into drivers not meant to play them (excessive in band and power demand) is sure to result in distortions of various sorts.
(b) in theory, passive crossovers can have as steep a slope as you please. But typically 12dB/8ave is used and, for sure, going steeper around 100 Hz would be rarely constructed due to the massive size of the parts (if you could find capacitors that are not electrolytic sort or inductors that don't have iron cores, both absolutely unpalatable to persons with gear like yours).
(c) not sure of my math, but your mid-range with a slope of 12dB/8ave would have a driver-smashing input at 50 Hz just 15dB down; for the woofer, not sure if the mechanism or the sound would be destroyed but duplicating the mid-range band but certainly you'd be getting unwelcome distortions of stereo localization. Also, hard to manage the system when there's so much overlap in regions of the band that are hard to manage acoustically in almost all rooms.
With an electronic XO, 24 or even 48 dB slopes are just a twist of the knob to audition and to A-B and to change. And you have a good chance of being able to fine-tune the drivers separately and successfully.
B.
(a) I believe that putting excessive bass or excessive treble into drivers not meant to play them (excessive in band and power demand) is sure to result in distortions of various sorts.
(b) in theory, passive crossovers can have as steep a slope as you please. But typically 12dB/8ave is used and, for sure, going steeper around 100 Hz would be rarely constructed due to the massive size of the parts (if you could find capacitors that are not electrolytic sort or inductors that don't have iron cores, both absolutely unpalatable to persons with gear like yours).
(c) not sure of my math, but your mid-range with a slope of 12dB/8ave would have a driver-smashing input at 50 Hz just 15dB down; for the woofer, not sure if the mechanism or the sound would be destroyed but duplicating the mid-range band but certainly you'd be getting unwelcome distortions of stereo localization. Also, hard to manage the system when there's so much overlap in regions of the band that are hard to manage acoustically in almost all rooms.
With an electronic XO, 24 or even 48 dB slopes are just a twist of the knob to audition and to A-B and to change. And you have a good chance of being able to fine-tune the drivers separately and successfully.
B.
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I've been unsuccessful in trying to obtain the Xover schematic of my Fried/Salk towers. What the slopes are, I have no idea. I have yet to pull them for the purpose of trying to draw a wiring diagram. A very famous fella, who designed the Xover, has yet to respond to my email requests.
Your knowledge exceeds mine concerning your technical assessment. As the TL xover is a 6db slope, I would not expect what you suspect but i most definitely heard something unusual with what you term as being an anomaly of stereo localizations while listening to familiar test tracks. Maybe you're on to something here.
Handling it all acoustically in the room, I can deal with. My room would surprise the hell out of any good fella and I still have more to finish building to make it even better. I get absolutely surprised from where the sound emanates from at times,,,its truely outstanding so I think I can deal with that.
Perhaps its been too many years since I explored the active Xover route but I just seem to remember the Marchand days of pulling and inserting the components to tailor make the acceptable xovver response one was searching for.
Your knowledge exceeds mine concerning your technical assessment. As the TL xover is a 6db slope, I would not expect what you suspect but i most definitely heard something unusual with what you term as being an anomaly of stereo localizations while listening to familiar test tracks. Maybe you're on to something here.
Handling it all acoustically in the room, I can deal with. My room would surprise the hell out of any good fella and I still have more to finish building to make it even better. I get absolutely surprised from where the sound emanates from at times,,,its truely outstanding so I think I can deal with that.
Perhaps its been too many years since I explored the active Xover route but I just seem to remember the Marchand days of pulling and inserting the components to tailor make the acceptable xovver response one was searching for.
Somebody is obviously counting the profit that a serious XO would cost the factory to install. If the XO point is like 100 Hz, you have several octaves very important for sound quality slopping across the line. But might sound kind of OK..... like vinyl recordings, I suppose.
Years ago, I was set upon the dahlquist Xover for the reasons you mentioned about just dialing it in. I have just recently tried to find it but with no success just in case that was the route i was heading for. what specific equipment do you propose i look at for that 'dial in' approach?
Behringer DCX2496.
Inconceivable to me today how anybody can develop a system without measuring and modifying iteratively (and finally by ear) using REW. Just flying blind otherwise or suffering from terminal auditory arrogance.
And to "dial-in" modifications, Behringer DCX2496, all-singing-all-dancing little miracle.
If you have unalterable prejudices against DSP, then use the DCX only to establish the corrections needed and then duplicate any you can (ha, ha) with hard wires.
B.
Inconceivable to me today how anybody can develop a system without measuring and modifying iteratively (and finally by ear) using REW. Just flying blind otherwise or suffering from terminal auditory arrogance.
And to "dial-in" modifications, Behringer DCX2496, all-singing-all-dancing little miracle.
If you have unalterable prejudices against DSP, then use the DCX only to establish the corrections needed and then duplicate any you can (ha, ha) with hard wires.
B.
not opposed to DSP because i have no experience with it but i am familiar with its many advantages. Really quick, reviews are touch n go with this piece but ill seriously look into it, its cost is cheaper than 2 healthy subamp plates and the upside is i do have a working 400 and wouldn't have to be concerned with selling 2 subamp plates for more than this is worth. thank you
you're slick......you're gently nudging me over to an electronic Xover knowing i want to use my TL;s.....
As with sightings of the Loch Ness monster by local hoteliers, the critical reviews seem to come from those selling upgrade mods. I have never seen depressing measurements posted and my own measurements are clean as could be.
You can, however, cancel half the criticism by bridging over the analog input stage using input with a digital signal (assuming you are digital upstream, as you would have to be with REW testing).
Once you have The Power of DSP in your hands, you'll never go back.
Ben and anyone else reading this thread if you're interested in modding, kevinkr is the man to talk to.