XKi - X's ab initio Karlson 6th Order Bandpass

The Jaw Horse holding the box made it a lot easier. The slot vent is now ¾" high, next comes duct work and exterior filling, sanding and finishing.
 

Attachments

  • 1002201610 - Edited.jpg
    1002201610 - Edited.jpg
    494.1 KB · Views: 275
@oldfi

I'd be really happy/proud to get a graph tnat nice ! plus the size is really good. Do you know of a modern speaker which should work in your Kabinet ?

And would you share its plan ?

here's your pic lightened a bit

FbsDOj7.jpg
 
Last edited:
The cabinet design and construction are detailed in the Lencoheaven thread - Car speaker recycle- under the Cabin Fever Competition--designed to use up stuff we have sitting around our garages and workshops.
the cabinet is very simple - a tuned port with flared ends at the top, the speaker baffle is tied into the bottom and the base of the tuned port. Nothing fancy. The front cavity between the Karlson elliptical opening and the baffle is packed at the top and sides with insulation in ground cloth bags, and this seems to tame the Karlson W response behaviour. The back chamber is packed with two bags of insulation to allow the wiring to pass through the middle of the cabinet to the back. The design is contained in an Excel spreadsheet, which you are welcome to, but I cannot post it
 
I was surprised by the driver, had initially just thought of using them as the bass driver in an otherwise open baffle speaker, but they were so good, I just went about tweaking the response. The biggest effects were from adding damping in the front chamber based on a comment I read somewhere that the W was due to resonances in the rectangular front cavity. The drivers are quite unusual nowadays, at 8 ohm impedance, whereas modern drivers all appear to be 2-4 ohms. I would have to start from scratch measuring TS parameters if I was to try again with a modern 6 x 9.
 
I found one other, more modern 4 ohm 6 x 9, which has a lower Fs and larger Vas, in my scrap bin. Working it up, the box size is 3 times the volume of this one...way too big, for what it is. I am afraid that more esoteric modern 6 x 9's, which have larger power handling capability, would have even larger cabinet requirements. No luck in finding a modern equivalent to the drivers that I used.
 
Hi oldfi and XRK971

- - Misco "had" a decent 6x9 (and at good price) but sold out

Oldfi, that was a nice result damping the front chamber, etc, of your XKi

Here, is the comparison - Oldfi , sorry I got your name wrong.

Also, I have a 10" Tymphany speaker coming. Michael Chua's test indicated lower mms than published spec. What kind of K would you build with this general set of specs?

Oldfi XKi before vs after damping the front chamber

https://i.imgur.com/DLPBidW.jpg

Tymphany 10 specs

Resonant Frequency (Fs)68 Hz
DC Resistance (Re)5.7 ohms

Voice Coil Inductance (Le)0.61 mH
Mechanical Q (Qms)4.4

Electromagnetic Q (Qes)0.37
Total Q (Qts)0.34

Compliance Equivalent Volume (Vas)1.76 ft.³
Mechanical Compliance of Suspension (Cms)0.173 mm/N

BL Product (BL)14.37 Tm
Diaphragm Mass Inc. Airload (Mms)31.41g

Maximum Linear Excursion (Xmax)2.3 mm
Surface Area of Cone (Sd)373.3 cm²

Mike Chua's test

https://i.imgur.com/BTeAYtx.png
 
The XRK design method comes up with the best compromise to live with the restricted Xmax. The best I could come up with was a 25 l back chamber, with a 6.25 l front chamber, which requires an internal set of cabinet dimensions of about 12 by 12 by 12 inches. The front Karlson coupler is about 9.75 inches long - starting about 2.25 inches from the internal cabinet top. The front to back tuning port is 1.5 inches high and 8 inches wide by 4.5 inches long , with flared ends. The fit of the speaker on the baffle is tight, top to bottom, but could just work with these dimensions, otherwise the cabinet would have to be made slightly taller and less deep.
 
Many Thanks - That is pretty cool - would be thrilled if could get some "hit" and perhaps LF down to 80-ish Hz. A rough sketch (side and top views) could help on the port spacing, baffle, etc. I assume there's no "upper board" above the slanted baffle. (?)
 
Last edited:
The port is built into the top plate (1.5 inches = two thicknesses of 3/4 inch plywood, with a 3/4 inch plywood plate underneath, which forms the bottom of the port, and the top attachment point of the slanted baffle). You are correct, there is no vertical plate, the baffle just attaches, with the mouth of the top port above it. I could try to get a picture of the cabinet design out of the EXCEL spreadsheet. I will see what I can do.
 
MANY THANKS - fantastic work and programming

Here's the plan with images at 900p width
 

Attachments

  • Tymphany Side 900 Web.jpg
    Tymphany Side 900 Web.jpg
    214.7 KB · Views: 225
  • Tymphany 10 SKi Top View Web.jpg
    Tymphany 10 SKi Top View Web.jpg
    284.9 KB · Views: 224
  • Tymphany 10 Xki Aperture Web .jpg
    Tymphany 10 Xki Aperture Web .jpg
    470.2 KB · Views: 218