bsacco1 Posted October 18, 2014 Share Posted October 18, 2014 I'm trying to calculate the proper speaker port diameter and length using a Klipsch K-43 woofer in a 14'x16"x28" speaker enclosure. Of course, I'd like to get the most amount of bass possible from the speaker enclosure and K-43 woofer. Does anyone know how to do this? Quote Link to comment Share on other sites More sharing options...
WMcD Posted October 18, 2014 Share Posted October 18, 2014 I haven't used it, but try http://www.micka.de/org/en/ Quote Link to comment Share on other sites More sharing options...
WMcD Posted October 18, 2014 Share Posted October 18, 2014 Here is a thread which provides the data on the woofer and a free program. https://community.klipsch.com/index.php?/topic/149779-klipsch-heritage-woofer-ts-spec-v16/?hl=%2Bk-43+%2B%26amp%3B+%2Bspecifications My guess is that your box is too small to get good results, but do try the program. WMcD Quote Link to comment Share on other sites More sharing options...
djk Posted October 21, 2014 Share Posted October 21, 2014 That box isn't big enough for a K43. Quote Link to comment Share on other sites More sharing options...
mustang guy Posted October 21, 2014 Share Posted October 21, 2014 (edited) That box isn't big enough for a K43. I don't agree. Plugging the K-43 numbers in, 3.101 cuft is the default tuned to 36Hz. The box size he is referencing is 3.05 cu ft using 1/2" plywood, and 2.78 cu ft using 3/4" plywood. Tuned at 45Hz, the curve looks real good... Edited October 21, 2014 by mustang guy 1 Quote Link to comment Share on other sites More sharing options...
mustang guy Posted October 21, 2014 Share Posted October 21, 2014 If you are using 1/2" material to build the case, the volume of the cabinet is 3.05 cu ft. The best tuning I could get was at 45Hz, and needed a 4" wide port ~2-9/16" long. Using 3/4" material, the cab would be 2.78 cu ft. The best tuning I could get was at 46Hz, and needed a 4" wide port ~2-13/16" long. The yellow line is the 1/2" plywood box, and the red line is the 3/4" plywood box. 1 Quote Link to comment Share on other sites More sharing options...
djk Posted October 21, 2014 Share Posted October 21, 2014 So the driver, port, and bracing have zero volume? And 3dB down at 50hz (or higher)? Quote Link to comment Share on other sites More sharing options...
Turbox Posted October 21, 2014 Share Posted October 21, 2014 Are you limited to this size? why not make it a bit bigger? Quote Link to comment Share on other sites More sharing options...
ClaudeJ1 Posted October 21, 2014 Share Posted October 21, 2014 50-60 Hz. is a perfect cutoff one uses a tapped horn sub. And if he is going to build a bigger box, why not build a Quarter Pie for all the benefits of HORN bass instead of bass reflex, or DJK's PPSL? Quote Link to comment Share on other sites More sharing options...
mustang guy Posted October 21, 2014 Share Posted October 21, 2014 So the driver, port, and bracing have zero volume? And 3dB down at 50hz (or higher)? djk, I ran the plot on a bin with double the volume, and the response is down to 39Hz. That is indeed a lot better, and although it is not as flat as the smaller box, it would be much better for bass frequencies. The efficiency is about the same in either case. I suppose it all depends on what your goal is. If you want to be dead flat to the THX 80 Hz, then the smaller enclosure will do that very well. If you want mostly flat and a whole ovtave lower (40Hz), then double your enclosure size. Point taken on the bracing and port volume. 2 Quote Link to comment Share on other sites More sharing options...
bsacco1 Posted October 21, 2014 Author Share Posted October 21, 2014 Thank you so much Mustang Guy, ClaudeJ1, Turbox, djk and William F. Gil McDermott! I'm a bit overwhelmed here technically. Basically here is my story. I inherited a pair of Klipsch Cornwalls that were re-sized into smaller cabs. I've attached a photo. See below As you can see there was no thought given to the original bass porting and the cabinet maker just eliminated it all together. As a result, these speakers lack bass response. In addition, these speakers are loaded with k-43's. I am not at technical when it comes to electronics or speaker design, though I have woodworking skills and could tackle blocking up these ports and re-designing an extended bass shelf port system of some sort. I just need the technical help found here on this forum to pull it off. I would gladly document the project in pics if someone would be willing to help me figure how to do it. Do I have any takers? Quote Link to comment Share on other sites More sharing options...
mustang guy Posted October 22, 2014 Share Posted October 22, 2014 What are those slot things between the woofer and the mid-horn? Can you post a higher resolution image? Those are tiny. 1 Quote Link to comment Share on other sites More sharing options...
mustang guy Posted October 22, 2014 Share Posted October 22, 2014 If those are ports, what are the EXACT dimensions of the the 4 separate sides? I can give you a port length based on that area, and the fact that your enclosure is about 2.61 cu ft. You will have bass to about 49Hz at -5db. With that cab sealed, you would get about 67Hz at -5db. Note: The regular Cornwall gets 38Hz at -5db. 1 Quote Link to comment Share on other sites More sharing options...
bsacco1 Posted October 22, 2014 Author Share Posted October 22, 2014 I'll post new hi-def pics tomorrow with exact inside as well as outside dimensions of the speaker box. re: Those slots you are referring to are actual cut-outs in the motor board to act as speaker ports. The other speaker has round holes (approx 2") as speaker ports. So both speakers have different shape ports. Yeah, I know it's lame...don't blame me...I didn't do it...I'm just trying to fix them! lol;) Once you get the pics you'll get more insight. The speakers do have a 2"x4" brace that runs front-to-back just above the woofer and below the mid horn connecting to the back wall of the speaker box. Quote Link to comment Share on other sites More sharing options...
bsacco1 Posted October 22, 2014 Author Share Posted October 22, 2014 OK , as promised here are the pics... The EXACT dimensions are: Inside dimensions: 16 5/16" wide x 28 5/16" high x 14 1/8" deep Outside Dimensions: 17 3/4" wide x 29 5/8" high x 15 11/16" deep https://www.flickr.com/photos/58668520@N00/15602679432/in/photostream/ https://www.flickr.com/photos/58668520@N00/15599176071/in/photostream/ Quote Link to comment Share on other sites More sharing options...
bsacco1 Posted October 22, 2014 Author Share Posted October 22, 2014 another pic https://www.flickr.com/photos/58668520@N00/15602679432/in/photostream/ https://www.flickr.com/photos/58668520@N00/15599176071/in/photostream/ Quote Link to comment Share on other sites More sharing options...
mustang guy Posted October 23, 2014 Share Posted October 23, 2014 (edited) Ahhhh! You were giving internal measurements in your first post. I was assuming you measured the outside of the box. The volume is right about 3.7 cu ft with bracing, internal horns, and cones. You are going to have to get rid of the existing slots. I would suggest a pc of 1/2" plywood glued and screwed to the inside of the motorboard, then cutting pieces to the exact size and glue and screw to that hole. Fill the rest with bodyfiller or something like it. Remove all screws once glue dries and cut holes for ports. Here are port lengths for various width ports when using two ports: 2 1/16" port x 2 cut approximately 3/4" long (0.75") 2 3/4" port x 2 cut approximately 2" long 3 3/4" port x 2 cut approximately 5" long When tuning a cabinet, nothing is perfect. though I am using the rated T/S specifications of the K-43-K driver, yours may not have the same specs! Start with cuts which are longer than recommended. Buy a couple spare tubes so you can experiment. 1/4" can make a difference... When tuned correctly, these should be dead flat to 64Hz, and roll off to 43Hz at -5db. That's not bad for this cab, as the regular CW gets 38Hz using a K33 which has a lower fs. Edited October 23, 2014 by mustang guy 1 Quote Link to comment Share on other sites More sharing options...
bsacco1 Posted October 23, 2014 Author Share Posted October 23, 2014 Thanks Mustang Guy! Just a quick question. Obviously you did the calculations based upon installing (2) ports per speaker? Do I have a (1) port per speaker installation option? Also, what is the difference between Flanged ports vs. straight ports. Do they have individual characteristics? -b Quote Link to comment Share on other sites More sharing options...
mustang guy Posted October 23, 2014 Share Posted October 23, 2014 A single 3 3/4" about 1" long would do it. Not sure about the flange port difference. I always assumed it was to reduce chuffing. 1 Quote Link to comment Share on other sites More sharing options...
mustang guy Posted October 23, 2014 Share Posted October 23, 2014 Point of note. At 100 watts, the air speed of the port will be over 100 fps at 45Hz. This will cause a noticeable chuff between 30 and 70Hz. If you use 2 ports as recommended in my first response, the air speeds will be reduced to 18, 10 and 5 fps at 100 watts in the 45Hz region. No chuffing... I would use 2 ports. 1 Quote Link to comment Share on other sites More sharing options...
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