OH here's that top stuffed graph with 1/24th octave smoothing
also shakey hand held graphs of the LASE 1.5"CD withtwo tubes-one ~1.5X Transylavnia power style
- theother a toilet paper roll. The high pass is some cheap 3uF/0.35 looking inductor section of an Audiopipe crossover.
also shakey hand held graphs of the LASE 1.5"CD withtwo tubes-one ~1.5X Transylavnia power style
- theother a toilet paper roll. The high pass is some cheap 3uF/0.35 looking inductor section of an Audiopipe crossover.
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I guessing the length of the slot and width of tube are the important parameters, and the tube can be as long as you want before the taper as long as it is behaving like a transmission line?
What is the effect on the response from the taper length and tube diameter?
What is the effect on the response from the taper length and tube diameter?
regarding the large 330Hz peak in my 8pe21 midrange coupler, is that the cavity resonance ?
could aperiodic tuning of the rear chamber somehow lessen that peak?
Ill pull the wings to see if the cavity alone (as a bad horn) is the largest contributor.
Perhaps the rear chamber is way too large and that the resultant shift in resonance from making the
rrear chamber "tight" might work in favor for the response ?
I need to get it to work with a passive crossover.
Below is the Z plot with no sponges in the front.
could aperiodic tuning of the rear chamber somehow lessen that peak?
Ill pull the wings to see if the cavity alone (as a bad horn) is the largest contributor.
Perhaps the rear chamber is way too large and that the resultant shift in resonance from making the
rrear chamber "tight" might work in favor for the response ?
I need to get it to work with a passive crossover.
Below is the Z plot with no sponges in the front.
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Hey freddi,
Thanks for taking time to measure and share that data! It's of particular interest as it's not terribly dissimilar to the mini-SK8 I sketched but never built.
The 330Hz peak does look like the front chamber cavity resonance. At least it's of lower Q than either my 4" XKi or TK6. If you get a chance, measure the response at ~12" with wings versus no wings. I forget, is the rear chamber sealed or vented on this one? I had lately been thinking I could improve my TK6 by having a semi-aperiodic large area vent in my reflector panel.
I tried FF125K in my XKi and although it meausres close enough to the W4-1320SIF, the latter sound much better in there for some reason. The XKi isn't bad, but I don't think it offers much over the direct-radiating DCR I have the W4 in, at least for my specific design and build. A 12" XKi might be pretty good and provide useful gains over a direct radiator.
These plastic K-tubes you have are pretty neat. If you can, I'd like to see the frequency response wide-open, with no crossover. I limit the sweep to 200Hz to make it easier on the driver. I've made a paper/fiberglass clone of the TPC but have yet to measure it, will share when I do.
Thanks for taking time to measure and share that data! It's of particular interest as it's not terribly dissimilar to the mini-SK8 I sketched but never built.
The 330Hz peak does look like the front chamber cavity resonance. At least it's of lower Q than either my 4" XKi or TK6. If you get a chance, measure the response at ~12" with wings versus no wings. I forget, is the rear chamber sealed or vented on this one? I had lately been thinking I could improve my TK6 by having a semi-aperiodic large area vent in my reflector panel.
I tried FF125K in my XKi and although it meausres close enough to the W4-1320SIF, the latter sound much better in there for some reason. The XKi isn't bad, but I don't think it offers much over the direct-radiating DCR I have the W4 in, at least for my specific design and build. A 12" XKi might be pretty good and provide useful gains over a direct radiator.
These plastic K-tubes you have are pretty neat. If you can, I'd like to see the frequency response wide-open, with no crossover. I limit the sweep to 200Hz to make it easier on the driver. I've made a paper/fiberglass clone of the TPC but have yet to measure it, will share when I do.
Hi IG81
Later tonight I'll try at least to get the midrange K's wings on/vs off @12" to mic response graphs..
K8MR is sitting at a height which puts the cone center up from the floor at about 30 inches. The back chamber is sealed which makes the ~330Hz peak worrisome. Maybe just a cap for its highpass would work?
I'll have to reduce the drive power for the CD-tube sweeps - I could feel a lot of power from that 1.5" compression driver
FWIW here's a fudged BP4 sim which may resemble what's seen -?
At some point and builds, one might be better off with an R-J as sponges and other band-aids would not be required
https://www.diyaudio.com/community/threads/nice-page-with-r-j-experiment.326562/
Look at my R-J graph with EV SP15A (Carl N. says that driver was used in Sun Studio's K15s)
It sounds very good for only about 2CF rear chamber)
Later tonight I'll try at least to get the midrange K's wings on/vs off @12" to mic response graphs..
K8MR is sitting at a height which puts the cone center up from the floor at about 30 inches. The back chamber is sealed which makes the ~330Hz peak worrisome. Maybe just a cap for its highpass would work?
I'll have to reduce the drive power for the CD-tube sweeps - I could feel a lot of power from that 1.5" compression driver
FWIW here's a fudged BP4 sim which may resemble what's seen -?
At some point and builds, one might be better off with an R-J as sponges and other band-aids would not be required
https://www.diyaudio.com/community/threads/nice-page-with-r-j-experiment.326562/
Look at my R-J graph with EV SP15A (Carl N. says that driver was used in Sun Studio's K15s)
It sounds very good for only about 2CF rear chamber)
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An Augspurger style style DCR or dual chamber reflex with single port exit aka "Double Bass Reflex/DBR" plus a lens such as JBL uses should be lots of fun with some speakers. The aspect of the opening might need some experimentation. Hornrep indicated some DBR scenario possess "hit" like some BVR.
Regarding "K8MR" I think the back chamber could be reduced quite a bit improving response - or at least greatly reducing cone-excursion below the passband. Wish I had some rigid foam-board insulation.
I'd "old" and as such exponentially running out of time - it would be cool to have some benevolent person with a tenatious grasp of Akabak3, and associated programs working 8hr/day on these damn K's. A Go fund me to pay that person too -lol
I have great respect of Karlson's abilities and K15 - K12. K12 with a right balanced speaker is very musical. Kaap12A has punch power. If I ever get my house back in livable order then will load Celestion K12-200TC - they are so much better looking basket wise,etc than the 10TF we used.
Regarding "K8MR" I think the back chamber could be reduced quite a bit improving response - or at least greatly reducing cone-excursion below the passband. Wish I had some rigid foam-board insulation.
I'd "old" and as such exponentially running out of time - it would be cool to have some benevolent person with a tenatious grasp of Akabak3, and associated programs working 8hr/day on these damn K's. A Go fund me to pay that person too -lol
I have great respect of Karlson's abilities and K15 - K12. K12 with a right balanced speaker is very musical. Kaap12A has punch power. If I ever get my house back in livable order then will load Celestion K12-200TC - they are so much better looking basket wise,etc than the 10TF we used.
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Is you HR simulation "done backward" to fit your measurements or was it done before, therefore predictive? It looks pretty close to your Z and FR graphs, nice!
Despite some improvements on my XKi (see the main XKi thread), I don't think it's something I'll be using much and going towards more of a RJ is what I had in mind as a plan B. It could be good to widen the narrow HF pattern of the W4-1320SIF. The 6L + 3L DCR I have them in is pretty good and measures quite flat.
Despite some improvements on my XKi (see the main XKi thread), I don't think it's something I'll be using much and going towards more of a RJ is what I had in mind as a plan B. It could be good to widen the narrow HF pattern of the W4-1320SIF. The 6L + 3L DCR I have them in is pretty good and measures quite flat.
"backwards" as I need to look at the plan to closer estimate volumes.
Maybe a tube absorber like you made -say 1.5" diameter damped tube turned "sideways" and placed at the very top of my midrange coupler's front chamber would be the kat's meow?
Perhaps making a back chamber volume stub connected to the top of the front chamber would have been the best route in the first place.
Maybe a tube absorber like you made -say 1.5" diameter damped tube turned "sideways" and placed at the very top of my midrange coupler's front chamber would be the kat's meow?
Perhaps making a back chamber volume stub connected to the top of the front chamber would have been the best route in the first place.
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That could work as a Helmoltz absorber.
You could try doing it on the cheap like I did: roll-up two ~2" diameter cardboard (cereal box or the like) tubes, 10.16" long for 332Hz, fit them one behind each wing with the open end upwards.
I did make a Helmoltz from a cut-up 0.5 liter peroxide bottle and slid-in the bottom until it measured 425Hz on the REW RTA when I blew in it. The final volume is quite small, so is the opening, so I don't know how effective it will be versus the 1" x 8" tube. I'll test that later or tomorrow.
You could try doing it on the cheap like I did: roll-up two ~2" diameter cardboard (cereal box or the like) tubes, 10.16" long for 332Hz, fit them one behind each wing with the open end upwards.
I did make a Helmoltz from a cut-up 0.5 liter peroxide bottle and slid-in the bottom until it measured 425Hz on the REW RTA when I blew in it. The final volume is quite small, so is the opening, so I don't know how effective it will be versus the 1" x 8" tube. I'll test that later or tomorrow.
Here you go - some measurements taken at 12" at a height (30" from floor) of the cone's center
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K8MR-8PL21 Wings On 9 Melamine pads 24th smoothed.jpg -
K8MR-8PL21 Wings On Pads installed Unsmoothed.jpg -
K8MR-8PL21 WINGS ON NO PADS 24TH SMOOTHED.jpg -
K8MR-8PL21 WINGS OFF 24TH SMOOTHED.jpg -
K8-8PL21 Wings Inverted No Smoothing.jpg -
K8MR Wings inverted 24th oct smoothed.jpg -
K8MR-8PL21 WINGS OFF 24TH SMOOTHED.jpg -
K8MR Unsmoothed wings Off.jpg
Thanks for the data!
Those melamine foam pads help quite a bit. If the 330Hz peak could be brought down ~6dB to the 1kHz level, it would be pretty good. I never though of inverting the wings, but it looks about like what I'd expect.
I guess it plays a fair 150Hz to 5kHz. You might be able to let it roll-off naturally if it weren't for that ~10kHz peak.
Those melamine foam pads help quite a bit. If the 330Hz peak could be brought down ~6dB to the 1kHz level, it would be pretty good. I never though of inverting the wings, but it looks about like what I'd expect.
I guess it plays a fair 150Hz to 5kHz. You might be able to let it roll-off naturally if it weren't for that ~10kHz peak.
as I fidget with REWI sstart finding the controls -here's 5dB/vertical division
Its pretty bumpy but usable. I think a different cavity,top stub, etc. could improve on things
I don't like the idea of running it low as there's only about 0.5mm overhang each way and I want it to play pretty snappy w/o damage. A tighter back chamber plus 2nd order highpass should work.
.
Its pretty bumpy but usable. I think a different cavity,top stub, etc. could improve on things
I don't like the idea of running it low as there's only about 0.5mm overhang each way and I want it to play pretty snappy w/o damage. A tighter back chamber plus 2nd order highpass should work.
.
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hey IG81
I hot glued a Delco marked version of the tw51 tweeter to a mini-klam lens - might be fun for a high (5K up) \or helper tweeter w.TW51 I'll do some graphs when jumpers ordered arrive.
IT might make a cool 2-wat with CD to mount high on a all and was sold that way with
Eminence Beta 8A and Eminence CD1 (AL diaphragm limited to ~ 12KHz)] compressions driver in a home theater set.which had some sort of K12 subwoofer.
Its not so smooth but I do like the90 degree off axis stuff
I hot glued a Delco marked version of the tw51 tweeter to a mini-klam lens - might be fun for a high (5K up) \or helper tweeter w.TW51 I'll do some graphs when jumpers ordered arrive.
IT might make a cool 2-wat with CD to mount high on a all and was sold that way with
Eminence Beta 8A and Eminence CD1 (AL diaphragm limited to ~ 12KHz)] compressions driver in a home theater set.which had some sort of K12 subwoofer.
Its not so smooth but I do like the90 degree off axis stuff
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Look at the wings off 1/24th octave smoothed plot )the mic position was a bit low).
The cavity alone is doing damage. What would you change in a new build?
Is there a simple change to the back chamber of the present cabinet to help or is the cavity's sidwalls domination? -why are the~950Hz then octave up dip so deep?
What might happen if holes were drulled at the top of the front cavity then resistively damped with cloth or foam? (with no change to either chamber )
I really think one might do better and not have to resort to sponges (or maybe a couple 0 in the front chamber. It would take some sort of cheap but sturdy test box where height and the board(s) above the speaker can be changed.
A foldback stub or tunable resonator could be part of a new design.
I wanted a squat midrange module and am not disappointed in 8pl21's dynamic capabilities.
The cavity alone is doing damage. What would you change in a new build?
Is there a simple change to the back chamber of the present cabinet to help or is the cavity's sidwalls domination? -why are the~950Hz then octave up dip so deep?
What might happen if holes were drulled at the top of the front cavity then resistively damped with cloth or foam? (with no change to either chamber )
I really think one might do better and not have to resort to sponges (or maybe a couple 0 in the front chamber. It would take some sort of cheap but sturdy test box where height and the board(s) above the speaker can be changed.
A foldback stub or tunable resonator could be part of a new design.
I wanted a squat midrange module and am not disappointed in 8pl21's dynamic capabilities.
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That 3D-printed min-Klam is pretty neat! The response isn't that bad to boot. I have taken some measurements on my DIY K-tube, eliptical and V-slot eliptical, I just have to compile, make sense of it and post, stay tuned!
Drilling holes in the front chamber will raise the resonance peak IMO, as happened with a more open flare on my XKi.
Drilling holes in the front chamber will raise the resonance peak IMO, as happened with a more open flare on my XKi.
- wonder how my mid coupler with 30uF series cap would fare when driven by a 2nd order ~375Hz highpass? (-don't have any resistors to load the generic Xpver's woofer and tweeter outs)
With regards to a midrange "module", what might be a good approach for aspect ratio - cavity shape to avoid dips in the first place before the aperture is added?
am not sure how this graph got attached as was meant for another thread
does editing allow for removal of images ?
With regards to a midrange "module", what might be a good approach for aspect ratio - cavity shape to avoid dips in the first place before the aperture is added?
am not sure how this graph got attached as was meant for another thread
does editing allow for removal of images ?