Nat Denkin

There should be no loss in content going from electrical digital to optical digital to electrical digital in the sense that a bit is a bit is a bit. Formats such as Apple Lossless and FLAC preserve all the information that was presented to those converters in a more compressed form than on CDs for example. Jitter can be an issue when converting digital formats and that must be considered when you go from one box to another either in the optical or electrical domain. A DAC requires a clock to determine when it is to decide whether a zero or a one has been received. Typically, that clock is derived from the incoming signal itself using a circuit that locks on the transitions in the signal. When the transitions are exactly spaced, the jitter is low; when the time between transitions varies, the jitter increases and the recovered clock may cause the DAC to produce the analog signal earlier or later than it should. Under normal circumstances, this should not be a problem. A bigger problem is that when streaming bits from the cloud, fewer bits means less transmission expense. Transmitting a highly compressed signal might be good enough for ipod use, but disappointing on a quality system. Material that is specially mastered for Itunes might be pleasing for most, but still may lack some of the information on the original. Bottom line: Rather than worry about optical or electrical interconnections, be aware of the quality of the source material. Wifi is convenient, but may limit what you are hearing.

The motorboard makes it much easier to install or replace woofers! I built the Speakerlab K (in 1984) and replaced them with Jamborees last year. They fit about the same in corners. When using 3/4" Baltic Birch, measure the thickness; mine was closer to 17.4 mm and the differences add up when you want a tight fit. Enclosing the Speakerlab K is highly advised especially if your walls are sheetrock. I was quite happy with the sound using Crites 1526c woofers, ALKs trachorn (Atlas drivers), Beyma CP25 tweeters and ALKs universal network. After 26 years of looking at the Speaker Ks, I just wanted a change. A real downside of the Speakerlab K is that they have essentially no resale value. Used Klipschorns might be a good alternative when you add up the real expenses of DIY. If you know how to make compound bevels, the Ks are a good project, otherwise, you might be better off with either the Jubilees or Jamborees that have few difficult cuts. Enjoy the project, nat

I recall that the CW1526 is similar to the pre-1984 K33 while the CW1526C is more similar to the later K33 woofers. I use the CW1526C and like them, but I would expect the CW1526 to have similar sound and be better matched to the earlier crossovers. Since you are building your own Cornscala, you should be able to tweak the design to get what sounds best to you. [:-)]

PWK was aware of Stenger's patent (granted in 1932) when the La Scala loudspeaker was designed. He learned from previous patents and taught in his. While ALK was not the first to use tapped autotransformers in crossovers (and I am not aware of any ALK patents), he clearly learned from previous work on RF filter design and considered both amplitude and impedance. His free disclosure of his designs is a valuable service to all DIYers who lack his knowledge and understanding. Paul Voigt used the tractrix design in the 1930's. Following Voigt's death in 1981, Bruce Edgar wrote about the tractrix design that was clearly learned by Martinelli. I own ALK universal crossovers and I have Martinelli 1" throat tractrix horns; while it is obvious that Greg learned from those designs, or the designs that preceeded them, Greg has made changes that may be of interest to the readers of this forum. "Ripped off" would be approptriate only if you have identified patent or trademark infringement. Other knowledge in the public domain is free for anyone to use. Discussion of competitor products on the Klipsch forum provides Klipsch free market research related to their product lines. When there is considerable interest in a modification or competing product, Klipsch (or the current owner) can use to update their designs and/or offer new products. The discussions here of both strengths and weaknesses would also be useful in future planning.

Greg has voiced the Vittoras to satisfy his ears. He has also expressed his preference for the sound of systems using simple crossovers. The crossover used in the Vittoras permits the user to alter the voicing to personal taste. Moving taps may affect the impedance seen by each driver or by the amplifier. Moving taps may also affect the crossover frequencies. The bottom line is how does the system sounds to each owner. To that extent, Greg offers a money back guarantee. Networks for the Klipschorn have changed over 60 years generally increasing the number of components and increasing the order of the crossovers. Yet some listeners, when replacing aging components prefer to keep the earlier, simpler designs. Greg built the 212 Hz mid-range horns that I use with Jamboree bass bins. Using an active crossover, I have tried different combinations of crossover frequency and filter order. I have my preference. I also have ALK universal crossovers and ALK 1 inch trachorns on my K-hron clones and think they provide excellent sound for the money.

Look at http://www.diyaudio.com/forums/multi-way/163536-1-compression-driver-8-ohm-vs-16ohm-2.html for discussion on the sensitivity of 16 vs 8 ohm drivers. It is an interesting discussion. nat

I programmed a Harmony 700 to operate the Jan Didden 6-channel volume control mod on a DCX2496 and also my Onkyo CD player. Now, if I could only use it to operate itunes... nat

I am using the Jan Didden mod described in http://www.linearaudio.nl/6chan-1.htm. It replaces the I/O stages completely and adds a 6-channel volume control and independent control of two new analog input stages. Also included is the ability to remote control the mod. I use a Logitech univeral controller to control the mod and also my CD player. I am also using itunes to store my CDs in Apple lossless format to play directly from my computer. I haven't figured out how to control itunes remotely. I have ordered another mod designed by Frank Oettle that improves the SRC and clock. The Crown D-series amps are frequently available on e-bay.which is where I got mine. The only concern I have about them is the power transformers can have a slight hum (which is hard to hear even in a quiet room unless you get close to them) . Depending on your patience, the price can vary. I got mine over the range $135 to $240 plus shipping. Sometimes a bunch come on at the same time and depress the price. Crown provides excellent support on line. The DCX2496 is popular for modding because it is relativly inexpensive and easy to mod. The analog circuits are frequently replaced and among the replacements you will also find tube amplifiers and transformers. There are lots of T-amps, class-D amps, and kits available, and it is often satisfying to built your own. While I would certainly recommend the components I used, there are many others discussed on this forum that fit a variety of budgets and that have been independently measured. My room is 13 foot wide except for a part that adds another three feet. The back of the room is open to a hallway so it is hard to define the length. At one time (long ago) I measured the bass response and found large variations because of standing waves. Some day, I might get around to trying some DIY bass traps and see if I can hear a difference. Enjoy the journey!

I just listened to the Kunzel Telarc and even with the Jamborees still on the dollies, you can feel the canon shots go right through your gut. I liked the Bob Crites CW1526C 15" woofers on my Khorn clones. Putting a pair of them in each Jamboree was one of my goals. The RTA showed that the CD was putting out uniform power from 20Hz to beyond 400Hz with each canon shot. The Jamborees probably are getting into the mid 30Hz region. Keep in mind that the horn mouth is not much larger than in the Klipschorn. I am tri-amping the drivers with Crown D-75A for the woofers which are wired in parallel. I am guessing that the Jamboree sensitivity is something like 107 dB so the Crown is more than adequate. I use another Crown D-75A for the BMS4592 midrange drivers and a Crown D-45 for the Beyma CP-25 tweeters. The woofers and midrange can handle anything the amplifers put out while the D-45 merely puts out 25 watts at 0.1% THD so I am not worried about frying the drivers and use nothing but wire (14 gauge) between the amps and drivers. A modified Behringer DCX2496 provides the digital active crossover and volume control. I am currently using a design by Le Cleac'h that varies the time delay correction and uses 18 dB/cotave Butterworth filters crossed at -5dB to provide less phase shift than you can get with passive filters. If you are interested in percussion, I think you can hear better imaging when the phase is not ignored. Any speaker you build yourself will sound better. When I finish the grills and fill in all the pockets I will put the speakers on the floor and measure the response. I know I have lots of room resonances so I may experiment with some base traps before I am done. The trouble is, I spend too much time listening to the speakers that I have little time to finish them!

While the Jamborees are a little larger than Klipschorns, the enclosed bass horns allows them to be away from the corners. Having the right tools certainly makes the job easier, but for the most part I got by with a small table saw, a sliding mitre saw, router, and lots of planning. There are some typos in the plans so you should draw it out full scale and building the entire project before glueing is highly recommended. Some of the pieces were challenging for me and the photographs above were intended to show how those pieces could be made. In the end, it was actually easier than I expected to make the pieces. I did talk with Greg Roberts about the Jamborees and he did the veneered panels I mounted on the front of Jamborees to match the Lavera Horns that are on top. Although I have built tractrix horns, they looked like I built them. Part of the deal for the entire project was that the finished product needed to look great as well as sound wonderful. Greg is wonderful to work with and was willing to customize his V-Trac horn to a lower cutoff and veneer it so the horn could be the center of attention and not merely hidden behind some grill cloth. After 26 years of looking at the clones I built before I met her, my wife is pleased by the results The Kreg Jig allows you to drill a counter sunk pocket hole in one piece and use Kreg's self tapping screws to solidly attach to another piece. While the holes can be plugged with matching or contrasting wood, with some planning, most of the holes are not visible. Kreg also has clamps that make it easier to hold the pieces together. Since the screws are self tapping, alignment of the pieces is easier. The local Lowes carries the Jig and other piece parts but an even larger selection can be found by googling Kreg Jig. I also bought a small electric screwdriver with a 90 degree attachment to get into tight places where a driver with a long bit simply won't fit. My table saw has 5/8 inch grooves so that standard tenon jigs (which required 3/4 inch grooves) would not fit. I built a jig that fit over the fence. Iit was too loose so I was able to use a cardboard shim to keep it tight. Had I planned it that way, I would have used something like teflon to make it slide easily. The jig was big enough to hold the wood securely with clamps so that I merely had to push the jig through the saw. I replaced the saw guard with clamped guards of wood to avoid having an exposed saw blade. That scene at the begining of "I Walk the Line" is sobering so I spent a lot of time thinking about safety. Whenever I did something stupid...like a wrong measurement, I stopped what I was doing and took a long break...often to the next day. It's not so much that I wanted perfection, but rather, I thought if I were making mistakes, an accident was waiting to happen. Making test cuts and lots of jigs helps to be accurate. I do not have much experience in woodworking. When I built the clones, I worked with three other guys who had more experience. This time I was on my own. I am very pleased with the results. The sound is excellent.

I need to remember how supportive my wife is; sometimes I forget. I work slowly so the mess was there for several months. The floor under Bogart is red oak. The planks are actually a laminate with something like an 1/8th inch of red oak bonded to some engineered wood that could be directly bonded to the cement slab. Our heating is thru the slab so the flooring has to deal with being hot part of the year. Upstairs we do have 3/4 inch red oak hard wood floors that I put in my self. I enjoyed that job so much that I keep the stapler out as a reminder.

You are so right! One visitor asked why I didn't extend the "bookshelves" all the way across. I am still deciding how to finish the grills. I might want to trim them with wood finished to match the mi-range horns. Of course, another approach would be to leave the Jamborees open. Mirrors might make them appear too busy [], but I wondered how that would look. Not too bad?

Having overgrown the dining room, the remaining construction is in the living room. A small dolly holds each bassbin off the floor for easier access. Lots of screws, glue, and clamps continue to be needed.

The splitter used the Kreg jig to great advantage to rigidly hold the various pieces together while the glue cured.

Braces are needed to control vibrations. There shape had to match the bevels and widths of the horns. A sliding mitre saw was purchased after failing to be able to do the job well with the table saw.