If it was me i would just add the FT17 in the supra baffle and add an lpad. I mean why add a tweeter that would double the cost of the project. XO around 10K where the 126 starts rolling off.
Even at my age and loss of HF hearing i can truly hear the difference with a ribbon tweet rolled in at 10Khz with the 208 sigma.
You are use to hearing quality HF, i think the 126 wont deliver what you are use to hearing. TC (RIP) and i exchanged several emails about this and i go along with him.
The only problem i see is the phase so with a first order XO to the tweet at 10 Khz would require the tweet be around .33 "(8.5mm) extened( closer to the listener) from the sound production plane (VC) of the 126/vrs the production plane of the tweet. This would compensate for time alingment.
Add the deflectors as this will control the LF wavefront and re-direct the wave forward and reduce booming. The cement walls that you have reflect a much higher amount of energy at all frequencies.
As an added note , i tend to look at a FR BLH with a wizzer as a 3 way system, not a FR system. It has all the phase problems of any 3 way system, but sometimes a bit worse. At least you can correct a bit with a seperate tweet.
ron
Even at my age and loss of HF hearing i can truly hear the difference with a ribbon tweet rolled in at 10Khz with the 208 sigma.
You are use to hearing quality HF, i think the 126 wont deliver what you are use to hearing. TC (RIP) and i exchanged several emails about this and i go along with him.
The only problem i see is the phase so with a first order XO to the tweet at 10 Khz would require the tweet be around .33 "(8.5mm) extened( closer to the listener) from the sound production plane (VC) of the 126/vrs the production plane of the tweet. This would compensate for time alingment.
Add the deflectors as this will control the LF wavefront and re-direct the wave forward and reduce booming. The cement walls that you have reflect a much higher amount of energy at all frequencies.
As an added note , i tend to look at a FR BLH with a wizzer as a 3 way system, not a FR system. It has all the phase problems of any 3 way system, but sometimes a bit worse. At least you can correct a bit with a seperate tweet.
ron
Added notes.
If no supra baffle was used a mini truncated pyramid baffle for the F17 in a tiny sealed enclosure might be the way to go. Mount it on the sides or top for a different high tech look and performance. On the top it could be slid back and forth to adjust with white/pink noise to achieve time alingment. Just find out where you want it and glue it down. If mounted on the top or sides i would lift the assy off the surface by around .66" (1/2 wavelength @ 10Khz) to allow for rearward diffraction.
ron
If no supra baffle was used a mini truncated pyramid baffle for the F17 in a tiny sealed enclosure might be the way to go. Mount it on the sides or top for a different high tech look and performance. On the top it could be slid back and forth to adjust with white/pink noise to achieve time alingment. Just find out where you want it and glue it down. If mounted on the top or sides i would lift the assy off the surface by around .66" (1/2 wavelength @ 10Khz) to allow for rearward diffraction.
ron
Hi Ron,
Well I'm wondering if I'm a bit hosed here. Myself and two friends just finished cutting all the wood for 3 pairs of A126 speakers with the side firing (L+R) horn mouth as apposed to rear firing. We used the plans from the Frugal-Horn page here... http://homepage.mac.com/tlinespeakers/FH/download/RonHorn-A126-plans260207.pdf
Now I see a completely different CC in this thread and it worries me that we did not cut for the latest design.
So far we have put one speaker together and listened to it.
Do you think there is any way we can modify the remaining pieces to adopt the newer plan with the larger CC? In any case, what is the expected sonic difference between the newer/larger CC and the older one we built?
Well I'm wondering if I'm a bit hosed here. Myself and two friends just finished cutting all the wood for 3 pairs of A126 speakers with the side firing (L+R) horn mouth as apposed to rear firing. We used the plans from the Frugal-Horn page here... http://homepage.mac.com/tlinespeakers/FH/download/RonHorn-A126-plans260207.pdf
Now I see a completely different CC in this thread and it worries me that we did not cut for the latest design.
So far we have put one speaker together and listened to it.
Do you think there is any way we can modify the remaining pieces to adopt the newer plan with the larger CC? In any case, what is the expected sonic difference between the newer/larger CC and the older one we built?
If I understood correctly the "problem" with smaller/larger CC sizes is at which point in frequency the horn loading starts i.e. the crossover point of the CC as a low pass filter as it were.
As I posted in the other A126 threads (linked in the first post) the computed CC volume for the drawing in the PDF stands at 1.69 liters. Apparently the recommended volume for the 126 is 2.2 liters (not 100% sure why...). The drawings used here simply attempt to correct that to a closer 2.1 liters.
Also, remember that the drawings in this thread are my own and were not "officially endorsed" so to say.
Now, how to model the CC lowpass as a function as a volume is well beyond me, even less so the LF "boost" by the horn itself. The only rough figure I remember seeing somewhere was that horn loading starts around 200 Hz for the 2.2 liter CC. To be very honest I would very much love to see such a curve (or guidlines wrt to that), not least to be in the know on how to dimension the SB....
For what is worth,
Florian
P.S. Just for the fun of it: Build a pair according to the PDF, build the 2nd according to my drawing and do a comparison. And then build the third pair in between
. And post the results here, of course.
As I posted in the other A126 threads (linked in the first post) the computed CC volume for the drawing in the PDF stands at 1.69 liters. Apparently the recommended volume for the 126 is 2.2 liters (not 100% sure why...). The drawings used here simply attempt to correct that to a closer 2.1 liters.
Also, remember that the drawings in this thread are my own and were not "officially endorsed" so to say.
Now, how to model the CC lowpass as a function as a volume is well beyond me, even less so the LF "boost" by the horn itself. The only rough figure I remember seeing somewhere was that horn loading starts around 200 Hz for the 2.2 liter CC. To be very honest I would very much love to see such a curve (or guidlines wrt to that), not least to be in the know on how to dimension the SB....
For what is worth,
Florian
P.S. Just for the fun of it: Build a pair according to the PDF, build the 2nd according to my drawing and do a comparison. And then build the third pair in between
. And post the results here, of course.To be very honest I would very much love to see such a curve (or guidlines wrt to that), not least to be in the know on how to dimension the SB....
Ok the horn roll off action is a slope, the roll in of the baffle action is nothing more than a shape that will support a spherical wave of a given size. If the launch area needs to support a given dia. then
(((lamda/pi) x .707)/2) is the minimum radius.
pi x R^2= area (for a different shape, but the wave will not form correctly from a shape with a greater aspect ratio than around 1:1.414)
The effective slope of the horn roll off is calculated,The intersection of the roll in slope of the baffle is calculated. They have to meet at an acceptable point of around -3db from the combined overlayed slopes.
All this would not be necessary if we could adjust to wider speakers like the old Lowther designs. In effect all the SB is ,is an OB that supports a given wavelength. So you can see the ratio of the CC volume to the size of the SB relationship. In effect you could use an SB on any cab, its just calculating in the roll off , the dip in the FR and blending in the wave support of the baffle size/shape to make a smooth transistion from one action to another. Its nothing more than a mechanical BSC.
ron
Ok the horn roll off action is a slope, the roll in of the baffle action is nothing more than a shape that will support a spherical wave of a given size. If the launch area needs to support a given dia. then
(((lamda/pi) x .707)/2) is the minimum radius.
pi x R^2= area (for a different shape, but the wave will not form correctly from a shape with a greater aspect ratio than around 1:1.414)
The effective slope of the horn roll off is calculated,The intersection of the roll in slope of the baffle is calculated. They have to meet at an acceptable point of around -3db from the combined overlayed slopes.
All this would not be necessary if we could adjust to wider speakers like the old Lowther designs. In effect all the SB is ,is an OB that supports a given wavelength. So you can see the ratio of the CC volume to the size of the SB relationship. In effect you could use an SB on any cab, its just calculating in the roll off , the dip in the FR and blending in the wave support of the baffle size/shape to make a smooth transistion from one action to another. Its nothing more than a mechanical BSC.
ron
help with bad lower-mid resonance
Well we finished one and auditioned it in mono. It's pretty remarkable how low this tiny driver can go in this cabinet. One thing though. When listening to Chris Isaak at anything above low volume levels, it's apparent there is an over-abundance of lower mids... to the point where it sounds like some kind of resonance (which is quite distracting). I am very familiar with Chris Isaak on other speakers and so I know it's not just a "bad" recording. The only deviation we made from the design was putting a small piece of Deflex on the back of the CC, *but* keeping the deflex 2 inches away from the throat opening.
I figured the deflex would be better than the styrofoam for killing bad reflections back into the cone. The other thing is we have not yet created the baffle-step compensation baffle. The wood we used was a quality 8 ply (birch or fir, I'm not sure) with no voids.
So what are the thoughts on why this is happening? Could it be the new driver which is not broken in yet? Is there any way to "tune" this problem out, say with stuffing the CC?
thanks much!
Well we finished one and auditioned it in mono. It's pretty remarkable how low this tiny driver can go in this cabinet. One thing though. When listening to Chris Isaak at anything above low volume levels, it's apparent there is an over-abundance of lower mids... to the point where it sounds like some kind of resonance (which is quite distracting). I am very familiar with Chris Isaak on other speakers and so I know it's not just a "bad" recording. The only deviation we made from the design was putting a small piece of Deflex on the back of the CC, *but* keeping the deflex 2 inches away from the throat opening.
I figured the deflex would be better than the styrofoam for killing bad reflections back into the cone. The other thing is we have not yet created the baffle-step compensation baffle. The wood we used was a quality 8 ply (birch or fir, I'm not sure) with no voids.
So what are the thoughts on why this is happening? Could it be the new driver which is not broken in yet? Is there any way to "tune" this problem out, say with stuffing the CC?
thanks much!
to the point where it sounds like some kind of resonance (which is quite distracting
Are you sure that the panels are glued properly? Never heard this one before?
I would remove the deflex first off, if you desire more rear CC damping Then a circular disk of styro around 3/4 to 1" thick on the rear of the driver will work.
BTW, as mentioned above, this is a pressure vessel with a long expanding vent, any leak in the pressure in the vessel ,not designed for, will have an effect on the balance of the system performance. I will not establish torque requirements for sealing (LOL).
ron
Are you sure that the panels are glued properly? Never heard this one before?
I would remove the deflex first off, if you desire more rear CC damping Then a circular disk of styro around 3/4 to 1" thick on the rear of the driver will work.
BTW, as mentioned above, this is a pressure vessel with a long expanding vent, any leak in the pressure in the vessel ,not designed for, will have an effect on the balance of the system performance. I will not establish torque requirements for sealing (LOL).
ron
To be very honest, I don't know but I don't think CC volume is relevant here. As Ron said, mine surely doesn't sound that way.
My best guess what Ron just suggested: Check and Double-check that everything is air tight. I was quite paranoid about that.
Florian
P.S. Are the side panels glued in place or are you listening with clamps only ?
My best guess what Ron just suggested: Check and Double-check that everything is air tight. I was quite paranoid about that.
Florian
P.S. Are the side panels glued in place or are you listening with clamps only ?
Thanks Ron. I seriously doubt there are any leaks of any kind. We used 100% polyurethane glue (aka Gorilla glue) for all the panels... which expands when drying and would have filled any cracks. And all the pieces fit tightly anyway - we did a good job with cutting all the pieces. Also knuckle rap tests find all the panels to be quite stiff/inert. It's not coming from the panels.
One think I just thought was it could be the room which was a live/reflective room. We'll have to hear it in another room.
One think I just thought was it could be the room which was a live/reflective room. We'll have to hear it in another room.
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