Reinout,
My latest K-Tube measurements and DonVK`s ABEC model are making me re-think how I set them up in addition to their crossover and EQ. I was wondering if you`re EQing yours in any way. In its vertical window, ignoring the un-slotted side, the 1" format 5.3" long tube rolls-off ~12dB/oct above a varying kneepoint with increasing listening angle. I would assume your TPC tube might be roughly like the blue trace below.
Your larger mid-tube probably does similar, with the effect simply shifted-down in frequency.
Of course the response of your FC driver will factor-in heavily and ultimately, the in-room power response will balance things out. I think your listening angle is pretty reasonable. I know I would likely need a bit of EQ above ~8kHz with my BMS 4550 or 4540ND and the level of absorption in my room, if set-up as you.
My latest K-Tube measurements and DonVK`s ABEC model are making me re-think how I set them up in addition to their crossover and EQ. I was wondering if you`re EQing yours in any way. In its vertical window, ignoring the un-slotted side, the 1" format 5.3" long tube rolls-off ~12dB/oct above a varying kneepoint with increasing listening angle. I would assume your TPC tube might be roughly like the blue trace below.
Your larger mid-tube probably does similar, with the effect simply shifted-down in frequency.
Of course the response of your FC driver will factor-in heavily and ultimately, the in-room power response will balance things out. I think your listening angle is pretty reasonable. I know I would likely need a bit of EQ above ~8kHz with my BMS 4550 or 4540ND and the level of absorption in my room, if set-up as you.
Good afternoon IG81,
i don't have that speaker-measuring stuff myself. Most of the time it is "using the ears" and tune the output till proper musical presentation (together with our audio group).
My set makes it possible to do a lot of smaller/larger changes:
So it pretty old-fashioned analogue here.
Nevetheless very nice results.
Regards,
Reinout
i don't have that speaker-measuring stuff myself. Most of the time it is "using the ears" and tune the output till proper musical presentation (together with our audio group).
My set makes it possible to do a lot of smaller/larger changes:
- tri-amped (and i can change volume of each amp);
- XO is tunable;
- all used drivers are field coils......and the used power supplies flexible;
- K-tubes are on a tilting system and can be brought forwards/backwards in order to keep all diaphragms in line.
So it pretty old-fashioned analogue here.
Nevetheless very nice results.
Regards,
Reinout
Attachments
Well you do adjust the in-room power response when going by ear. It`s mostly how I set up my original TPC tubes about 10 years ago. I assume picture #2 from the left above is roughly your listening position? Then you have the tubes firing towards you horizontally. Again very room-dependent, but I would favor a slightly off-axis position in my case, at least on paper, but would re-adjust with subjective impressions. I will be setting-up my latest DIY pair of 7.5" long tubes soon enough.
Hi IG81,
succes !
I'm still impressed with the horizontal coverage of a K-tube. I can really walk in the room and still experience stereo.
There is no sweet-spot but a proper sweet-zone in the room. Highly appreciated when listening with a group.
Love the colour of your K-tube......the eye is "listening" as well....
Regards, Reinout
succes !
I'm still impressed with the horizontal coverage of a K-tube. I can really walk in the room and still experience stereo.
There is no sweet-spot but a proper sweet-zone in the room. Highly appreciated when listening with a group.
Love the colour of your K-tube......the eye is "listening" as well....
Regards, Reinout
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Thanks, but I just copied the Volvotreter horn colour scheme, always liked the grey and orange... Your aluminum+blue looks pretty good as well. If you or a member of your audio club ever gets around to measuring these large tubes, do share here, I`d be very interested in seeing the results. I have output down to 700Hz with the BMS 4550 on the 7.5" tubes, I imagine yours can go quite a bit deeper. It does not load like a proper horn, but most quality drivers can likely handle it at domestic SPL`s.
Correct, my WVL AD-5110 are 2" drivers and work between 500 Hz and 4250 Hz. This driver has an efficiency of 110 dB in that frequency range....don't need massive power to generate a wall of sound.
An audio-collegue overhere uses Altec 2" on the same K-tubes from 300 Hz onwards without problems.
He modded a lot on his diaphragms; i use standard standard Radian 1245's.
Noted the measuring-request. If available i'll post it here.
An audio-collegue overhere uses Altec 2" on the same K-tubes from 300 Hz onwards without problems.
He modded a lot on his diaphragms; i use standard standard Radian 1245's.
Noted the measuring-request. If available i'll post it here.
Attachments
After a serious waiting time the prototypes of the alu-milled 1" K-tubes arrived. Nice to see the difference between the original K-tube (black) and the fres milled newer version.
Obvious difference is the tube-length. The original K-tube is somewhat stubby; with a longer slot/tube you are more in control of the spreading/direction. This has the same ratio of the larger 2" K-tube so now the 2 coverage diagrams are more alike.
Not so obvious is the resonance control
The original K-tube can/does resonate which has a negative effect on pinpoint imaging / staging. With the 2" K-tube we made use of the combination of 2 different materials. That worked. And now for the new 1" version we opted for a different route: different thicknesses of the tube-wall ! The miller was not really happy as he had to make that hole excentric......
And to be completely in line with the original we asked for a 2 degree tapering.
Proto pair arrived
New K-tubes inserted in the audio-set:
Details:
Very happy with the first results.
A follow-up pair will arrive in a couple of weeks (neater metal work) but in the meantime i can use these to the max. As the imaging is more thight the next modification in the set should be more clearly: totally different tubes for the tweeter-amp (TC03/5 and the CV1660).
Enjoy your music and audio-efforts !
Regards, Reinout
Obvious difference is the tube-length. The original K-tube is somewhat stubby; with a longer slot/tube you are more in control of the spreading/direction. This has the same ratio of the larger 2" K-tube so now the 2 coverage diagrams are more alike.
Not so obvious is the resonance control
The original K-tube can/does resonate which has a negative effect on pinpoint imaging / staging. With the 2" K-tube we made use of the combination of 2 different materials. That worked. And now for the new 1" version we opted for a different route: different thicknesses of the tube-wall ! The miller was not really happy as he had to make that hole excentric......
And to be completely in line with the original we asked for a 2 degree tapering.
Proto pair arrived
New K-tubes inserted in the audio-set:
Details:
Very happy with the first results.
A follow-up pair will arrive in a couple of weeks (neater metal work) but in the meantime i can use these to the max. As the imaging is more thight the next modification in the set should be more clearly: totally different tubes for the tweeter-amp (TC03/5 and the CV1660).
Enjoy your music and audio-efforts !
Regards, Reinout
Commercial and off-topic posts moved to Vendors BazaarThis weekend was a proper measuring & listening session.
After using the set that long you get accustomed to the sound ; you therefore loose objectivety.
2 extra sets of ears, a lot of measuring equipment (LeCroy Wavepro 950 scope; Rohde & Schwarz UPL audio analyzer), some sound meters and microfones and a lot if time made it possible to measure and adjust the set to it's current optimum.
checking....checking....
Noted a "non-linearity" in the frequency plot at the crossover from woofer-to-mid: adjusted the XO from 500 Hz to 350 Hz. Hurray for Nelson Pass XO-efforts (PAP-C1); so easy to adjust.
Adjusted the 3 power amplifiers to the required/needed output. Very happy with the decision that all the amps will have an internal volume control. Now it's easy to adjust the 3 tube amps (35TG tube to the woofer [8 W] ; 6C45 tube to the mid [2,6 W] ; VT105/ML6 tube to the high {1,1 W] to all drivers who have serious different efficiencies.
Aligning the K-tubes to get the proper musical presentation. That was fun as there were in essence 2 options:
Of note: this is personal opinion. In our group we both have persons who like the directly-fired solution but also persons who like the tilted K-tube.
Currently i have the K-tubes at 50 degrees.
Besides that K-tube-adjusting also "new" equipment has been added to the set: a Pass Labs Digital 1 DAC. A DAC from 1997 (first version; no modifications) which i spotted for sale in the internet. A properly executed BurrBrown PCM63P-K DAC; impressive bass and musicality.
Nothing wrong with a nice executed design....
Last changes to the set was a modification to the tweeteramplifier. I have a couple of tube-options to choose from but the Ce (Posttube) triode as the driver is seriously good sounding. Problem with that tube is availability and therefore the demotivating price.
In my preamplifier project i listened to many many options and 2 of them were sounding very good in the mid & highs but were simply lacking some oomph in the lower registers. Not to be used in the full-range preamplifier but no problems in a tweeter-amp.
And now i can use those CV1660/LS7 triodes (GEC / MOV manufactury = Marconi Osram Valves) and Philips TC03/5 triodes. These can still be found for reasonable money; in fact....i have them already.
Very happy with the results !!
Projects in progress:
Happy listening.
Regards, Reinout
After using the set that long you get accustomed to the sound ; you therefore loose objectivety.
2 extra sets of ears, a lot of measuring equipment (LeCroy Wavepro 950 scope; Rohde & Schwarz UPL audio analyzer), some sound meters and microfones and a lot if time made it possible to measure and adjust the set to it's current optimum.
checking....checking....
Noted a "non-linearity" in the frequency plot at the crossover from woofer-to-mid: adjusted the XO from 500 Hz to 350 Hz. Hurray for Nelson Pass XO-efforts (PAP-C1); so easy to adjust.
Adjusted the 3 power amplifiers to the required/needed output. Very happy with the decision that all the amps will have an internal volume control. Now it's easy to adjust the 3 tube amps (35TG tube to the woofer [8 W] ; 6C45 tube to the mid [2,6 W] ; VT105/ML6 tube to the high {1,1 W] to all drivers who have serious different efficiencies.
Aligning the K-tubes to get the proper musical presentation. That was fun as there were in essence 2 options:
- with the K-tube more directed to the sweetspot. this delivers an in-your-face highly detailed presentation. Very demanding to listen to as you can hear every detail.
- with the K-tube more directed upwards so you get the sound through the slot. This delivers a wall-of-sound in a sweet zone (much larger than above mentioned). Soundstage is huge and you can still pinpoint the musicians and instruments at the stage. This is more relaxed listening and my preferred choice.
Of note: this is personal opinion. In our group we both have persons who like the directly-fired solution but also persons who like the tilted K-tube.
Currently i have the K-tubes at 50 degrees.
Besides that K-tube-adjusting also "new" equipment has been added to the set: a Pass Labs Digital 1 DAC. A DAC from 1997 (first version; no modifications) which i spotted for sale in the internet. A properly executed BurrBrown PCM63P-K DAC; impressive bass and musicality.
Nothing wrong with a nice executed design....
Last changes to the set was a modification to the tweeteramplifier. I have a couple of tube-options to choose from but the Ce (Posttube) triode as the driver is seriously good sounding. Problem with that tube is availability and therefore the demotivating price.
In my preamplifier project i listened to many many options and 2 of them were sounding very good in the mid & highs but were simply lacking some oomph in the lower registers. Not to be used in the full-range preamplifier but no problems in a tweeter-amp.
And now i can use those CV1660/LS7 triodes (GEC / MOV manufactury = Marconi Osram Valves) and Philips TC03/5 triodes. These can still be found for reasonable money; in fact....i have them already.
Very happy with the results !!
Projects in progress:
- K-tube in brass (with the variable wall thickness)
- looking for a serious active crossover to seperate the mids and highs. Currently done passive but after last weekends session i noted the flexibility to react to measurements.
Happy listening.
Regards, Reinout
Hi Reinout
its surprising to me to see almost no one adopting or even trying a K-tube approach. FWIW I decided over 20 years ago that it was valid subjectively and could be preferred over a WG/horn.
Your system and new treble tubes are beautiful - including the DAC. I've an old Audionote AD1865 DAC plus modern Chinese DAC using that chip which I like.
Are any of the members experimenting with bass-midrange cone driven K-coupler? My old K18 with curved reflector was very good - perhaps by accident / "luck" more than knowing "how" to design.
Best wishes,
Freddy
its surprising to me to see almost no one adopting or even trying a K-tube approach. FWIW I decided over 20 years ago that it was valid subjectively and could be preferred over a WG/horn.
Your system and new treble tubes are beautiful - including the DAC. I've an old Audionote AD1865 DAC plus modern Chinese DAC using that chip which I like.
Are any of the members experimenting with bass-midrange cone driven K-coupler? My old K18 with curved reflector was very good - perhaps by accident / "luck" more than knowing "how" to design.
Best wishes,
Freddy
I've been watching this thread, though I haven't been able to experiment this year until about now 🙂
If I used an Eminence Alpha 8a, what size tube would I make, and what range should I expect it to cover? Hopefully it would work as a midbass driver, which I could then crossover to a compression driver.
If I used an Eminence Alpha 8a, what size tube would I make, and what range should I expect it to cover? Hopefully it would work as a midbass driver, which I could then crossover to a compression driver.
Good evening Freddy,
in our audiogroup we have several members who use K-tubes for highs and/or mids. All the drivers are compression drivers as we did not have favourable experiences with the combo of a K-tube + cone driver.
One of the reasons is that the efficiency of a compression driver is normally MUCH higher than cone drivers and as we are serious tube affecionados we love efficiency.....
In November the ETF will take place. This European Triode Festival is a 4 days audio-event for the serious DIYer. Our audiogroup is invited and i will bring in the speakers in our group. It's an open baffle for bass (Supravox driver) + a K-tube for mid/high (field coil von Langa). 100 dB....
Will be fun.
I took an younger version of these speakers to an earlier ETF and was pleased to see/hear that they could fill both small and serious large rooms with a correct sound. Given the amplification and source of course but with 150+ DIY-"audioholics" i'm pretty sure this will be catered for.....
Regards, Reinout
in our audiogroup we have several members who use K-tubes for highs and/or mids. All the drivers are compression drivers as we did not have favourable experiences with the combo of a K-tube + cone driver.
One of the reasons is that the efficiency of a compression driver is normally MUCH higher than cone drivers and as we are serious tube affecionados we love efficiency.....
In November the ETF will take place. This European Triode Festival is a 4 days audio-event for the serious DIYer. Our audiogroup is invited and i will bring in the speakers in our group. It's an open baffle for bass (Supravox driver) + a K-tube for mid/high (field coil von Langa). 100 dB....
Will be fun.
I took an younger version of these speakers to an earlier ETF and was pleased to see/hear that they could fill both small and serious large rooms with a correct sound. Given the amplification and source of course but with 150+ DIY-"audioholics" i'm pretty sure this will be catered for.....
Regards, Reinout
Hi Reinout
I would imagine once plus K-tube not so good but Robert Reams used what I believe was an Electro-Voice EV12L with a double slotted pipe (called the "Clothespin" as a midrange for his Karlson Hypex speaker.
What I'd like to know is if any of your members use a conventional Karlson for their bass / or midbass unit. That would seem more sensible than trying a large "K-Tube" or "Klam" - although I had decent results with a 15 inch klam and coaxial speaker.
Alpha 8A has decent sensitivity but a weak motor. It probably would play pretty well in a stock or "Dutch" K12 although their back chambers are larger than whats recommended by Eminence for bass reflex. (K12 have played well with FE206, BetsyK, B20) If any low end peaking occurs, then that could be tamed by empirically damping the vent, perhaps with something like a "Scotchbrite" pad or just grill cloth if the peaking is mild.
A K-tube could be rolled in with Alpha 8A around 2K5. Pelanj has a 3D print file for a double slotted K-tube which sounded quite nice and lively.
Best !,
Freddy
ps. FWIW here's the 15 inch klam. Klam/clam projectors were meant to be mounted high towards the ceiling, or on stands for PA work. Two of Karlson's AP100 which were also marketed as Oliver's "MAgna Klam" were installed at Radio City Music Hall. I believe they used an Altec 421 woofer plus a K-tube and University Sound compression driver.
Klam are awkward shaped things to manage plus the speaker is buried proportionately deeper compared to the first Karlson arrangement. That said, I think one could be a good performer, perhaps for a small outdoor event.
Reinout, please take some video at the big event !
I would imagine once plus K-tube not so good but Robert Reams used what I believe was an Electro-Voice EV12L with a double slotted pipe (called the "Clothespin" as a midrange for his Karlson Hypex speaker.
What I'd like to know is if any of your members use a conventional Karlson for their bass / or midbass unit. That would seem more sensible than trying a large "K-Tube" or "Klam" - although I had decent results with a 15 inch klam and coaxial speaker.
Alpha 8A has decent sensitivity but a weak motor. It probably would play pretty well in a stock or "Dutch" K12 although their back chambers are larger than whats recommended by Eminence for bass reflex. (K12 have played well with FE206, BetsyK, B20) If any low end peaking occurs, then that could be tamed by empirically damping the vent, perhaps with something like a "Scotchbrite" pad or just grill cloth if the peaking is mild.
A K-tube could be rolled in with Alpha 8A around 2K5. Pelanj has a 3D print file for a double slotted K-tube which sounded quite nice and lively.
Best !,
Freddy
ps. FWIW here's the 15 inch klam. Klam/clam projectors were meant to be mounted high towards the ceiling, or on stands for PA work. Two of Karlson's AP100 which were also marketed as Oliver's "MAgna Klam" were installed at Radio City Music Hall. I believe they used an Altec 421 woofer plus a K-tube and University Sound compression driver.
Klam are awkward shaped things to manage plus the speaker is buried proportionately deeper compared to the first Karlson arrangement. That said, I think one could be a good performer, perhaps for a small outdoor event.
Reinout, please take some video at the big event !
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Hey Reinhout, one idea for an electronic crossover is Sublime Accoustics. It is a simple, but elegant design - certainly worth checking out:
https://sublimeacoustic.com/products/k231-stereo-3-way-active-crossover
As I said earlier, I use Karlson K15 for 60 to 500 hz, a 5.5 inch Lowther in a 30 x 60 front waveguide for 500 to 8K hz, and a Karlson tube (PVC pipe) for a super tweeter using a 1 inch compression driver.
It would be fun to try a Karlson tube in front of the Lowther to see how it would work out. I imagine I could use a PVC pipe reducer to decrease the tube diameter from around 6 inches down to something like a 3 inch slotted tube, at least to try out. What do others think about this? Most PVC reducers have a fairly steep angle from the larger diameter pipe to the smaller diameter pipe which would probably not be ideal...
A 2 inch compression driver would certainly be easier to implement.
Retsel
Hi Retsel - you might try your Lowther in a small "Karlson" - I don't know what front cavity shape would give the smoothest response without damping material.
Regarding a 2 inch driver , PRV's inexpensive D2200
PH is well regarded for use with horns - It might actually work alright on a 2 inch tube - - https://prvaudio.com/products/d2200ph/
I wish Carl N. were available via email. I doubt if he would give specifics - I could call but it takes every bit of my wind to talk with damaged vocal cords.
Regarding a 2 inch driver , PRV's inexpensive D2200
PH is well regarded for use with horns - It might actually work alright on a 2 inch tube - - https://prvaudio.com/products/d2200ph/
I wish Carl N. were available via email. I doubt if he would give specifics - I could call but it takes every bit of my wind to talk with damaged vocal cords.
Thanks Freddi for the suggestions. As far as Karlson boxes for the Lowthers, I think that XRK's XKi design would work good for this driver. I believe he designed a version for a low Q Fostex driver which should work well for this Lowther. I hesitate for trying this because when I experimented with the K15 boxes I have which have EVM 15L drivers, running the frequency response up higher than 500 hz (maybe 2000 hz) ended up with muffled midrange and revealing the breakup modes of these drivers. I fear that the midrange in such a Karlson box would lose too much transparency compared to the waveguides I currently use. But I really should experiment to find out. Based on my concerns about Karlson boxes and midrange, I wonder if a large Karlson tube would work well for Lowther drivers. I guess I would need to experiment to find out.
Thanks for the 2 inch PRV compression driver suggestion. Some compression drivers seem to perform better than their price, so it may be fruitful to experiment with these before thinking about something more expensive.
Retsel
I was interested to read about your friend modifying his Altec diaphragms. Can you say what it was that he did to them? Thank you.