Ok , lets see what you have ...... If it looks good and meets all of your requirements then we can translate it over to the layout together ..
Nice ranges to work within. Gives us a little flexibility but not too much
Ok , Freddi, if you are happy with all three of those Delta 10a based Karlflex models shown then this gives us some solid guidance since all three of these models are very similar . .
Between the three models we have:
Rear volume = In the 20liter to 24.5 liter range (suggesting that the front chamber volume including Freddi-Mod Stub doesn't need to be any larger than 12.25 liters) .... This is going to be a small cabinet!
Interchamber duct CSA = 134cm2 to 182.5cm2 range (i suggest going with the higher end here to keep air-particle velocity low) ..
Interchamber duct length = We see up to 4.4cm in one of your models , which is very short giving us this high fundamental tuning (the high tuning is appropriate for a bright 10" PA driver) ..
NOTE: If we have to increase the CSA of the interchamber duct in order to keep the Air-Particle Velocity within acceptable bounds then that means we would also need to make that duct longer in order to achieve the same tuning ...
Freddi-Mod Stub (stuffed) length = In the 25.5cm to 28.3cm range ...
Freddi-Mod stub (stuffed) Cross Sectional Area = 134.5cm2 to 144.5cm2 range ... That is a small amount of area but if that is what works then that is great .. .. Have you tried more CSA here?
NOTE: This will be easiest if the Cross Sectional Area of the Freddi-Mod stub and Interchamber duct are matching ..
Ok , Freddi, if you are happy with all three of those Delta 10a based Karlflex models shown then this gives us some solid guidance since all three of these models are very similar . .
Between the three models we have:
Rear volume = In the 20liter to 24.5 liter range (suggesting that the front chamber volume including Freddi-Mod Stub doesn't need to be any larger than 12.25 liters) .... This is going to be a small cabinet!
Interchamber duct CSA = 134cm2 to 182.5cm2 range (i suggest going with the higher end here to keep air-particle velocity low) ..
Interchamber duct length = We see up to 4.4cm in one of your models , which is very short giving us this high fundamental tuning (the high tuning is appropriate for a bright 10" PA driver) ..
NOTE: If we have to increase the CSA of the interchamber duct in order to keep the Air-Particle Velocity within acceptable bounds then that means we would also need to make that duct longer in order to achieve the same tuning ...
Freddi-Mod Stub (stuffed) length = In the 25.5cm to 28.3cm range ...
Freddi-Mod stub (stuffed) Cross Sectional Area = 134.5cm2 to 144.5cm2 range ... That is a small amount of area but if that is what works then that is great .. .. Have you tried more CSA here?
NOTE: This will be easiest if the Cross Sectional Area of the Freddi-Mod stub and Interchamber duct are matching ..
A couple of rough edits
Ok , here we go ...
Freddi, now that i realize that this cabinet is probably around 12" deep i can see that the duct concept which you came up with earlier works out well if we need to make the Freddi-Mod stub 28cm long in a cabinet this size ....
See the rough edits below, FM-K2 (your duct idea) works out better than the FM-K1 at this cabinet's depth .......
FM-K2 style looks like a winner, shall we move forward with it and proceed to fill-in the rest of the details?
What are your thoughts Freddi ?
Ok , here we go ...
Freddi, now that i realize that this cabinet is probably around 12" deep i can see that the duct concept which you came up with earlier works out well if we need to make the Freddi-Mod stub 28cm long in a cabinet this size ....
See the rough edits below, FM-K2 (your duct idea) works out better than the FM-K1 at this cabinet's depth .......
FM-K2 style looks like a winner, shall we move forward with it and proceed to fill-in the rest of the details?
What are your thoughts Freddi ?
Attachments
MMJ - -I think its worth a try - assuming it can retain my fetish of a K-aperture. There's a "K10" in my pile with roughly 28/14 liter chambers - and it can hit hard. That one has too much energry around 210Hz.
Does it seem counterproductive to make the back chamber any larger for that driver? THe model didn't seem to want to go much lower by adding volume plus too much might take away the magic of low excursion in the passband.
If built, an adapter ring could be used to try 8 inch drivers.
What should the aperture look like area wise and flare wise?
At this size I think 1/2" Baltic birch will do - IF there's some on-edge. bracing on parts. With regular K-type having the port up in the section of the front chamber where the aperture area is very small, there can be considerable pressure. I've seen 18mm wings deflect almost a half inch peak to peak with tabla CDS and with every beat. (the wings were on 7/8" cleats and secured with 10-32 screws) When there's space, its good to have dowel struts to the wings to reduce flexure.
I appreciate your wizardry
and time - - plus have faith that hornresp fudges, once pinned down, can do some prediction of otherwise - "funky stuff"
If you could suggest the cabinet dims and cavity depth - those will go to my cutter "today".
Here's one example of making S1 -S1 larger - not sure if an improvement - of course a real sbub's area could be tweaked
with foam blocks
Does it seem counterproductive to make the back chamber any larger for that driver? THe model didn't seem to want to go much lower by adding volume plus too much might take away the magic of low excursion in the passband.
If built, an adapter ring could be used to try 8 inch drivers.
What should the aperture look like area wise and flare wise?
At this size I think 1/2" Baltic birch will do - IF there's some on-edge. bracing on parts. With regular K-type having the port up in the section of the front chamber where the aperture area is very small, there can be considerable pressure. I've seen 18mm wings deflect almost a half inch peak to peak with tabla CDS and with every beat. (the wings were on 7/8" cleats and secured with 10-32 screws) When there's space, its good to have dowel struts to the wings to reduce flexure.
I appreciate your wizardry
and time - - plus have faith that hornresp fudges, once pinned down, can do some prediction of otherwise - "funky stuff"If you could suggest the cabinet dims and cavity depth - those will go to my cutter "today".
Here's one example of making S1 -S1 larger - not sure if an improvement - of course a real sbub's area could be tweaked
with foam blocks
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Matthew - according to the schematic from one example above it looks like fhe front chamber would be around 16 liters (segments 2 +3 volumes) sans the stub volume. Is that correct?
Does segment 2's lenth correspond well to the "upper half" of the front chamber's height? What can
be adjusted there with some confidence ?
Lets say I want to examine that 8.5 liter front chamber for xrk971's XKI. What would be done?
Does segment 2's lenth correspond well to the "upper half" of the front chamber's height? What can
be adjusted there with some confidence ?
Lets say I want to examine that 8.5 liter front chamber for xrk971's XKI. What would be done?
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Freddi, Yessir, we wouldn't want you to be deprived of your fetish!
In those models that you have worked out and posted recently (with the Delta 10a ) it looks like you have exactly the right amount of volume in the back chamber for that tuning .... Your lower response knee is well defined but not underdamped nor overdamped, it is just right ... Coincidentally XRK's 1x10" plan has the right amount of volume in the back chamber even though that design was originally intended for a much lower fundamental tuning ..
Freddi, that is up to you .... You are more familiar with which Aperture/Slot shapes have been more successful in Karlson cabinets.... You may have a better understanding & better "feel" for this than anyone else on the planet right now ... You are Captain Karlson!
Agreed, just find ways to brace it ..
This is really your wizardry I am just here being supportive as you implement it .... ... The two changes that we made to XRK's design here were both your ideas, and they are excellent ideas
, so give yourself some credit here It is looking like XRK's original outer dimensions work perfectly for us because we end up right at where we need to be with the internal volumes (and close enough with the rear/front volume ratios if we stick with XRK's baffle angle) ....
Yes, I think they might be almost identical to X's alignment ...
If our Freddi-Mod stub has a Cross Sectional Area of 143cm2 and is 28cm long then that results in almost exactly 4 liters of volume in the stub, and if we add that to the 8.5 liters in the traditional front chamber of X's cabinet design then we end up with a total combined front chamber volume of 12.5 liters which is incredibly close to half of 25.5 liters ...... A 2:1 ratio ...
Unfortunately no, as far as i am aware there still is no accurate way to go about modeling a Karlson's front chamber/aperture/slot in Hornresp ..
You would do that by making the S1 and S2 CSA 143cm2 and L12 28cm in length ..... NOTE: S2 and the interchamber duct (Ap1/Lp) connect directly together in the Hornresp model but reducing the CSA of the interchamber duct to 143cm2 may be problematic when it comes to air particle velocity , so this is something that needs to be checked on with enough voltage driving the model to make the driver hit it's Xmax rating ..
Freddi,
The CSA of the interchamber duct needs to be made large enough to keep the air particle velocity below 20 meters per second (at the duct) when the driver is being pushed hard enough to hit it's Xmax rating ..
Freddi ,
I imported the hornresp record that you attached to post #2249 ..
Good news ... Looks like the interchamber duct only needs to have about 145cm2 CSA in order to avoid problems with Air-Particle Velocity , even if the driver is pushed to 6mm of excursion
...... So you were totally right about 180cm2 being an unnecessarily large duct ....
Did i ever tell you that you have a very good feel for this? You are good at this..
145cm2 also happens to be the area figure which you can use with the Freddi-Mod Stub resulting in just enough volume to get our combined front chamber to rear chamber volume ratio extremely close to a 2:1 ..
I imported the hornresp record that you attached to post #2249 ..
Good news ... Looks like the interchamber duct only needs to have about 145cm2 CSA in order to avoid problems with Air-Particle Velocity , even if the driver is pushed to 6mm of excursion
...... So you were totally right about 180cm2 being an unnecessarily large duct .... Did i ever tell you that you have a very good feel for this?
You are good at this..145cm2 also happens to be the area figure which you can use with the Freddi-Mod Stub resulting in just enough volume to get our combined front chamber to rear chamber volume ratio extremely close to a 2:1
..
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Freddi,
Since the Freddi-Mod stub takes the place of the old interchamber duct it seems to me that we can go with X's original outer dimensions considering that our new interchamber duct doesn't have enough depth to take up any significant volume of it's own ..
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well - in the dream land of wishful thinking - its getting closer (146cm.2 model is attacjed)
Since the model says a stub of 10.5" is ok, can we assume the small unslotted portion of the front panel effectively lenghtens that stub "a bit" ? If so, should the gap between the stub's front edge and inside of the front panel be made the height of the stub opening - ?
Will the stub board be less than 10.6" in length due to the front panel proximity and "left turn" added kength of that duct?
How deep should the cabinet be to make things work in harmony?
- its getting closer (146cm.2 model is attacjed)Since the model says a stub of 10.5" is ok, can we assume the small unslotted portion of the front panel effectively lenghtens that stub "a bit" ? If so, should the gap between the stub's front edge and inside of the front panel be made the height of the stub opening - ?
Will the stub board be less than 10.6" in length due to the front panel proximity and "left turn" added kength of that duct?
How deep should the cabinet be to make things work in harmony?
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