Mike Dubay

Decided to go with Clarity Caps ESA for the perminent cross over. I have used the Clarity Cap SA and was pleased, wanted at step up from there. The 6.2 uf capicator was on back order, and with no good idea when they would arrive, I substitued a 4.7 and a 1.5 in parallel. Hey some time you end up using two caps instead of one because you come up with a funny cap value. I will not loose any sleep over the two extra connections.

The average per driver: Woofer 67.9 db Squaker: 68.0 Tweet: 68.9 Pretty good results in matching the drivers attenuation. It sounds right to my ears.

And the same averaged response per driver:

Repeated the experiment at the same 4 positions. A plot of the db data:

Here is version 2 with the mids atten at -8 db.

Yes, I have been considering biamping. My cross overs do have separate bass and mid/tweet inputs. I'm considering using my SE amp for the mid and tweeter, and the Adcom for the bass bins. With the 107+ db/watt for the mid range the 5 watt SE would be sufficient. There has been some discussions on biamping in other parts of the forum. Still not sure if it is worth it or not, it sounds like fun thing to try. It is either that or build a nice pair of KT-88 PP amps. I believe my next item to address is that I need a better CD player. Maybe go with an esoteric A/D converter since my current player has a digital out.

I like the brace design, it will give side to side stability and you can use it to support the driver. Excellent cabinetry! What will be your finish, paint or veneer?

Need to apply some stats to squeez out some information. I calculated the average of the dbs for each driver, 30 to 400 Hz for the woofer, 800 to 4000 for squawker, and 4000 to 14000 for tweeter. woof: 72.2 db sqawker: 74.4 db tweet: 73.1 There is a 2.2 db difference between the squawker and the woofer, and a 1.3 db difference between the squawker and tweeter. Ahh, agreed with what my ears where telling me, slightly shy on bass. Note in the plot I also put a line representing he variation above and below the average. Thus 95% of the variation is between the line above and below the average. From this I determined that, instead of -6db attenuation for the mid, will change to -8db attenuation. The 1.3 db difference between the mid and tweeter is pretty small compared to the large amount of variation in the tweeter. Thus the diffenence between tweeter and mid is not significant, it is mostly due to the varation in the measured valued. So will leave the mid/tweeter balance alone.

So here is the raw data in db from the test tones: Hz A B C D Average Pink 62 62 64 64 63 30 71 70 74 73 72 40 78 78 78 77 77.75 50 72 73 76 73 73.5 60 68 70 72 66 69 100 73 66 75 69 70.75 125 67 70 73 75 71.25 250 75 78 75 74 75.5 400 75 76 68 75 73.5 800 79 64 72 81 74 1000 75 72 82 75 76 1250 79 77 78 81 78.75 2500 73 77 78 65 73.25 3150 70 69 74 68 70.25 4000 70 74 73 79 74 5000 77 77 80 79 78.25 6000 73 77 72 78 75 7000 87 80 86 88 85.25 8000 74 69 84 83 77.5 9000 77 77 81 77 78 10000 71 66 74 69 70 12000 69 65 74 64 68 14000 64 62 68 62 64 A plot of the data is attached.

The test rig consists of a pawn shop Dennon CD player, acquired for $5. It skipped before I cleaned the laser lens, which I pointed out to the pawn shop owner vehemently. A passive attenuator based on an ALPS potentiometer, the Adcom amp, and a Radio Shack digital SPL meter mounted on a tri pod. And a test tone CD with various frequencies from 30 Hz to 14,000 Hz. Due to the in climate weather, and the 130 lbs of mass for each speaker, the testing was done in place in the listening room. I am looking for a general balance between the drivers, so some averaging and smoothing will need to be applied. In room frequency responses do look gruesome. To average things out I marked out four positions in the room that the frequency response would be measured. Two positions on axis for the left speaker, 6 and 8 feet away, two positons on a line equidistant from the speakers, also 8 and 6 feet from front of speakers.

So the first impressions. First the Dayton caps are know to take some time to 'run in', so for the first minutes or so the mids sounded very "veiled" and an over over lack of bass. Listened for a week, between and hour to 3 hours of listening a day. The mids cleaned up dramatically, ok getting closer to the sound I was looking. The large mid horns give a very detailed smooth midrange. To help in the bass extension I replaced my SE KT88 amp with my ADCOM 454, much more bass to begin with. The cast Crites woofer sound spetacular. Can hear every bass note clearly, and the detail of each note. Yes, yes, this was what I was looking for. Still seemed a bit shy in the bass response area, so time to get the measurment rig out.

Cross over is in an "AA" style, but with a second order cross over for the tweeter. Used the Crites 3636 attenuator, input on the 0 5 taps, and output on the 3 and 0 taps, to give a 6 db reduction in the tweeter and squaker. During the design process I used some inexpensive capacitors, once the design is set then some more costly caps will be installed. The inexpensive caps are the Dayton Metallized Polyporpylene, inductors by Jantz and ERSE.

From behind the listening coach.

Painted the grills matte black, covered with speaker cloth. Used velcro squares to hold in in place, an inexpensive quick solution. The right channel.

Out of focus bisket joint.

Bottom grill.

Jump to the speaker grills. I bit different that most people make them. I use hard wood strips, biskets, glue blocks, and urethane adhesive. There is a couple of places where is have just about an inch of clearance to put the speaker grills. I was concerned that cutting them out of a solid piece of birch plywood would create a weak spot. Here are the tops.

They certainly rank 4 out of 5 stars in the sore back scale. I read a quote that here, near the 45th parrellel, that I live farther north than 95% of all Canadians, thus the Great White North, hey...

Good luck on the project! I see your wood worker friend used a bisket joiner. What type of glue did he use? I would second the notion for upgrading to a wood horn as a future project. Here is a photo of my split Cornscalas in progress.

I will, I'm beginning to reach critical mass and will need to start cleaning out my work shop. I would like to listen to your k horns with my SE amplifier someday.

Herb, You got me interested so I got my bath room scale out, came in a 130 lbs each. Thanks for the complement.

The image in the back ground is not accidental. Although her death was over shadowed by the loss of MJ the same day, it had a more pronounced affect on myself. The "Farrah blue" picture was in my bed room during my teen age years in the mid 70's. It was the image I pondered while listening to my first stereo. She pased during the bulid perod of the GWNCSs, June 25 was a sad day...

Now the the day to put it all together. Bolted the woofers in place. Glued the 3/4 inch blacked out spacers to the bass bins, and screwed the bases and the top cabs. Have what looks like a pair of speakers! No music yet, have to build the cross overs.

6V6 mono blocks. My first non kit based point to point hand wired PP amplifiers.

What I'm listening to now.