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PrestonTom

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Everything posted by PrestonTom

  1. Dr Who, 1) Yes you still need a mono amp for the center channel 2) I built both versions. You are correct about dropping the level down to line level and having to amplify again. However, in the top version you lose a bunch of gain on the L & R channels. In my case, I was using a passive preamp and did not want that. 3) No way around it, you still need another amp (or channel) for the center Good luck, -Tom
  2. They regularily come up for sale on eBay and Audiogon. A typical price would be $600-800. This depends on condition and finsh primarily. The Shipping costs/headaches should also be considered. In the early 80s the CW went through some changes and became the CW2. Both before and after this; however, there were some incremental changes within the each series. These included included slightly different dreiver/horns, crossover mods, and orientation of the horns. Although these changes would alter the sound, they will all have a fairly similar sound (more similar than dissimilar). I did want to mention that if you are patient, you can get a deal on these. In my case, my good fortune was due to some very kind and conscientious members of the Forum who scour all the local papers and classifieds and share the info with the rest of us. In my case I was able to get a pair of mid-1980s Cornwall 2s (oiled oak in very good condition) for only $400 (located in about a one hour drive). I have benefited from the kindness of these good Forum members. Good luck, -Tom
  3. Let me ask the very, very obvious question (before folks get into suggestions about esoteric audio cable ....) You mentioned that the cabinets were demo models at the stereo store. What did they sound like at the store (assuming they were reasonably set up in a corner)? Was the bass lacking and the highs overly bright? If not, then the path heads toward setup, location and room treatment (although were they being run with very different electronics at the store?). If the sound was similar, then this is now an issue of trying to muck with electronics and room treatment to change the sound. I have older K-Horns (and also Conrnwalls). In my opinion (and this is certainly painting with a broad brush), the K-Horns sould sound more similar to the Cornwalls you are already familiar with. The highs should be approximately similar and the bass (with some caveats) should also be similar Good luck, -Tom
  4. I am also interested in trying a mod or an upgrade for a CW 2 crossover. The topic has drifted a bit, however. The ALK mod for a Cornwall is NOT meant for a Cornwall 2. Getting back to the original question: Has anyone thought through (perhaps even simulated / built / measured) a crossover for a Cornwall 2. I appreciate that there is a great deal of work in crossover design and I also appreciate that not all Cornwall 2's use identical drivers/horns. So the question becomes especially tricky. I am interested in your collective wisdom. Good luck, -Tom
  5. I am going to definitely agree with the folks who are mentioning: speaker placement and room treatments. The room treatments (as first step) can be fairly simple, such as adding (or removing) an area rug, carpet pad, drapes, wall hangings, or removing a couple of pieces of furniture. The effects are real! -Tom
  6. Yes, Malcolm is absolutely correct. Outdoors is best. Folks usually do this because there is a lack of sensitivity or other signals creep in (a couple of reasons for that). An indoor/amplied antenna usually is pretty ineffective. I don't know the specifics of your situation, so take my advice with a grain of salt. What I did (I live in a semi-rural area in Southern New England) was to mount a Yagi antenna on the roof. You can get a dedicated FM one at Radio Shack. They have 2 versions. When they are on sale they are $15 & $19. Get the more expensive one. These are quite directional so you probably also need a rotator (about $35). This will give you better gain and also reject unwanted signals (same freq but but from another direction). The option of puttin it in the attic is tricky, Even though there may not be much metal in the attic (of a typical house), they do seem to work very well in practice. Good Luck. -Tom
  7. Good Question. The Watco products are great for the oil finishes (great for re-finishing also). The process is a bit involved to do it on frequent basis, but be sure to follow the instructions. Regardless of what you end up using, please do NOT use any product that contains silicone (these are usually in the products that you would use on a weekly/monthly basis). Good Luck, -Tom
  8. Yes, it is a good starting point. They have a similar tweeter and a roughly similar mid-range. The cabinets are a mangable size and cost. Similar to their big brothers, they are amazingly efficient. You will not need a big amp or one that delivers a lot of current. However, the amp (and other compents) must deliver a clean signal. Any hiss or hum will become quite audible. It's a nice journey - welcome! -Tom
  9. I appreciate al the the interesting comments I have been getting so far. Yes, I have been ignoring the fact that the distortion in a ss amp is not always when it is being driven at max levels. I also forgot to mention that this is strictly for music (no HT) so no sub-woofer is required - I would not want to muck up the low-freq response of the K-Horns A number of folks have been recommending tube amps. That is natural in this sort of context. However, in my mind, I am not sold on the "tube sound" . The overall differences between a decent SS and decent tube amp are complex and varied. However, for me, I do not prefer the tube sound. This is not baiting and it is not meant to be controversial. It is simply my preference. One thing I forgot to mention is that I have not yet refreshed the crossovers on my K-Horns (or the Cornwall center) yet. I am not convinced that the latest flavor in capacitor construction will create some acoustic magic. However, some good folks on the forum have made a reasonable argument that refreshing the caps in order to eliminate resistance that has built up over the last 24 years would be beneficial. The notion of putting a resistor in series with the drivers is pretty convincing. Perhaps I should do that first. I have held back partly out of laziness (hey, I am remodeling my kitchen right now - with no end in sight). But I have also held back because of the interesting threads regarding crossover design. Design is a complex issue with many variables and compromises. I am very tempted by a steep slope filter (for the woofer/mid) that Al K has made available. He makes some very interesting and thoughtful arguments (my cabinets currently have original AA networks) and the center is a Cornwall II (circa 1987?) . Previously I had auditioned K-Horns driven by Luxmans and by Haflers and was blown away by the sound. That was motivated me to get some K-Horns myself back in 1996. I still love them although I do dabble with panel speakers in my other set ups. I do appreciate everyone's perspective. I assume that I am merely going through what the rest of you went through before. I want to capitalize on your collective experience. Thanks, -Tom
  10. Thanks for the opinions so far. Unfortunately it is a bit difficult to describe the audio expereince with the different amps. I originally got the Hafler to drive some Magnepans (they are a tough load - inefficient and and low impedance). The Hafler did pretty well, and it seems to do okay with the K-Horns .... but not great. I have it driving the Cornwall center channel where it seems to be a better match. The Carver TFM I have found to be clean in its output (pre-amps have been a larger source of noise, hiss, & hum). But again the sound is nothing special. Actually at the low frequencies the Hafler seemed to do a better job. At the higher frequencies, the Hafler is probably preferred. To my ears, the Carver was a bit harsher than the Hafler. The mids semed to be more accurate with the Carver. In either case there was sufficient power / headroom so the there was no distortion or clipping. Thanks again and I know you guys have solved this problem before (specifically: matching solid state amps that I could not afford 20-30 years ago with K-Horns). All opinions welcome, -Tom
  11. I confess I have a bit of the upgrade fever right now. I am currenrtly using a Hafler amp with my K-Horns. There are so many neat solid state amps from my youth that are now reasonably priced that I am interested in sampling some of them (NAD, Rotel, Luxman, Adcom, Onkyo, HK, Phase Linear, Marantz, etc) . To start with, are any folks also using Carver TFM models, or the Phase Linear versions, or Hafler amps with K-Horns. What are your impressions? I am not interested in enormous amounts of power but rather in a wonderful sound. Some of the equipment I have tried has suffered because they were not sufficietly clean. The K-Horn's efficiency make the noise, hiss and hum come through (this was the case for or the Dynaco, or at least the ones that I tried). Your opinions are appreciated. I listen to Classical & Jazz (CDs not vinyl) at reasonable levels in a 12x19 room Thanks in advance (I know it is a difficult question since we always focus on our "own" systems), -Tom
  12. Michael, Thanks for the post. However, I am still confused about where the DC might be coming from. Let me digress. When I was new to DSP, I frequently would make a waveform (in floating point arithmetic) that would exceed the number of bits (when converting to integer arithematic) during the DAC conversion. It's a rookie error, and everyone in the lab was guilty at one time or another. We would always catch the error when we hooked up the spectrum analyzer. If we were generating a sine wave for instance and went beyond the 16 bits, the signal was definitely clipped. The tops and bottoms (an AC waveform) were both flattened out. This I believe is the same thing that happens with an amp that cannot drive the transducer "far enough" (perhaps a lack of sufficient / transient levels of current - if the driver has a low impedance). I assume the effect is comparable if the driver excursion is impeded in a mechanical fashion. The reason I mentioned the specrum analyzer is that the effects of a clipped waveform were easily seen. There was harmonic distortion at the odd harmonics. With a Fourier analysis this would also be expected. My question: if the clipping is for both the "tops" and the "bottoms" of the waveform (and clipping from the mechanical limitations may not be the same) and the clipping in both directions is the same magnitude, then where is the DC coming from? Additionally, the harmonics introduced were usually 10's of dB down so I can't imagine that any extra energy going to the tweeter would be appreciable. Certainly the signal sounded like crap, but I don't see where the damage would be coming from. Is it the case that the clipping is asymmetric (more flattening in one of the directions). Then certainly a DC component would be added. Curious, -Tom
  13. Yes, it is a good obeservation/question! At very low frequencies much of the level you receive at the ear is very much a function of room geometry/acoustics. With very long wavelengths, drapes, furniture and carpets do very little to break up the low frequncy waves. Consequently, what you heard (the increased level) was due to standing waves. Bass traps (usually placed in the corner) are one of the few ways that you can even out the sound. So that is a possibility. The other major approach is to experiment and move the position of the speakers (mostly relative to the floor, if they are on risers, and relative to the rear and side walls). This will certainly impact the imaging & sweet spot however. Additionally, when you re-locate the speakers it will not typically reduce the uneveness of the low- frequency repsonse. Rather, it will shift the loud & weak spots to a different frequency region (you will still have standing waves). Good luck, -Tom
  14. Re: "Q" or quality factor I am confident that both Al and Shawn know the definition, but I did not want others to get confused. The "Q" is a relative measure of the bandwidth of a filter (or other devices) . The measure refers to the ratio of the center frequency divided by the bandwidth. Where bandwidth is defined by the half power points (3dB down points) . So if the device lets frequencies 10% (above and below) around either 100 Hz or a 1000 Hz (or bands of 20 Hz and 200 Hz) then the Q in both cases is the same: 5. So it is a measure of bandwidth relative to the center frequency. The bigger the number, the sharper the tuning. Good luck, -Tom
  15. It really would be a crap shoot. Without having the T/S parameters, you are setting yourself up for a series of headaches. The cabinet geometry, porting, crossover, insulation are all designed and tweaked for the specific driver. The K-33 is a good driver already. Is there some aspect or deficiency that you are concerned about? Good Luck, -Tom
  16. Gee, I could not disagree more with The Ear's (tactless) comment. My thought is that I would like sire children with Amy. The offspring would be beautiful -Tom
  17. I have a couple of the other NAD tuners in the 4XXX series. They are quite affordable and pretty good quality. So I believe they are a good value. I will say the biggest improvement came when I placed a $19 Yagi FM-antenna (Radio Shack) on a rotator up on the roof. I listen to a bunch of NPR & college stations in Southern New England. Good Luck, -Tom
  18. Joe, That's great that the re-arrangement is working out well. By the way, a false corner, or half of a false corner, is a fun project that you might consider. One thing I like to do every few months is to move my listening chair forward or back about 1-3 ft. It will certainly change the sound - both the coloration and the imaging. It helps remind you about where the best sweet spot is. Enjoy and good luck, -Tom
  19. Okay, I am starting to undersatnd the issue now. .... First, using an equalizer is not really a very good way to tame room acoustics. Second, Dr Who gave some very good advice. Good Luck, -Tom
  20. Have to ask.... How does one measure the speaker system's impedance (including the crossover as part of the circuit) with a DMM? Is that what you meant to imply? -Tom
  21. If it is the low bass that you are concerned about (yet within the range of the cabinet's specified roll off) , then much of the final level (at your ears) will be determined by room acoustics. The Heresys are fairly efficient and do not present a terribly low impedance to the amp. So I do not beleive a different amp will solve the problem (unless it has very little power). If the 2 channels are in phase, then try (in a systematic manner) varying their position relative to the rear walls and side walls (of course have them on the floor or on a small riser). The wavelengths are fairly large (10 ft at 100 Hz) and your room may have a geometry that produces some strong nodes & anti-nodes. With decently recorded sources and an adequately sized amp, room acoustics are probably the culprit. Good luck, -Tom
  22. You are actually asking a pretty tough question. If you are satisfied with the bass, then you are way ahead of the game. I would sugesst spending some time experimenting with the locating the speakers and chair (use a carefully recorded CD and listen, listen, listen at various locations and arrangements). The determine what deficits you think you have, this is sometimes difficult to put into words or categories. The frequency response should be even and the imaging should be good. Detemine the deficits and then treat the room. As others have mentioned, the treatments can range from decorative ones (drapes, curtains, wall hangings) to ones you find in a studio (sonex etc). Good luck, -Tom
  23. ---------------- On 8/25/2005 1:24:35 PM psg wrote: I gotta ask... Why a center speaker? What needs to be filled-in? My KHorns are 18' apart. When the lead vocals come on, they sound as if they originated from the center speaker over the TV. Except that speaker is not playing at all. There's no need to fill in anything. Is this needed when they are spread apart more? ---------------- The deficit is one of spatial imaging. Fortunately it is not severe but it is most noticeable with widely separted speakers. The term "hole in the middle" is a bit unfortunate since you will still get a phantom center (when the L & R have identical signals). However the center (usually percussion and vocal) may not be as "solid" (it is hard to describe - also the sweet spot may be smaller or more fragile). The center channel will cure that. I think (my opinion so don/t go wild) it may also help with some room acoustic issues. Since each channel (L & R) is producing some delay and add filtering ("comb filtering"), the center may smooth that problem out. Yes, the center will also produce comb filtering, but it is unlikely that the "delay & add" would be the same as the L & R components. So the sum would be smoother. I hesitate to bring this up since this issue is causing various misunderstandings in another thread. Additionally, you are now also listening to the summed signal from a speaker that is on axis (the L & R may not be) so you may get a better frequency respeonse for that reason. Setting up a center is fairly simple. Give it a try. good luck, -Tom
  24. ---------------- On 8/24/2005 9:47:09 PM DeanG wrote: I can't think of a faster way to stress a tube -- ice it and then expose it to room temperature. "If you are using Klipsch speakers do not worry about fancy amps (the cabinets are efficient and present an easy load for an amp." Just because a speaker is efficient doesn't mean it presents an "easy" load. All of the stock networks present fairly reactive loads to an amplifer, and my personal opinion is that they present anything but an "easy" load for an amp. No, you don't need a "fancy amp", but you should probably make sure you have one that delivers flat response while being presented with large swings in impedance. No big deal with solid state, but tube users need to choose wisely. ---------------- Dean, We probably do not have a major disagreement here. My context is that folks seem to spend a great deal of energy / money on the particulars that do not matter as much (proper speaker set up vs mystical cryo-treated speaker wire ...). However, I am sure you will agree that an efficient speaker is easier on an amp (less likely to driven into distortion, clipping etc). Although the Klipsches do not have a constant impedance (not many systems do), they are easy on an amplifier (yes tube amps are more effected by a non-uniform impedance). However, it is when a speaker system presents a very low impedance (e.g. an electrostatic going down to 2 Ohm) that it becomes most difficult for an amp to drive (tube or SS). A Klipsch does not go that low and consequently does not require an amp with beefed up current capability etc. I am sure that we do not disagree on that. This is why I claim that a Klipsch is an easy speaker (compared to others) for a amp to drive (as long as it is of adequate size and has no hiss/hum). Regarding the original topic about Cryo-voodoo.... This is nonsense! Folks would do better by spending their energy on speaker set up and room treatment (those efeccts are not voodoo - they will make a difference) -Tom
  25. Gilbert, A center channel box is really quite simple. Look up the diagram from the DFH postings (Dr Bill had one, as did others). There are two configurations. The bottom one listed uses the outputs from the amp and then inserts a few 1/2 watt resistors and a resistor pot (audio taper). I find this configuration to have some small advantges. In addition a small plastc project box and some RCA connctors are needed. These are basically Radio Shack parts and will not cost more than about $10. All you need is a solder gun and handrill. I would not bother with the dynaco version, at least not as a first step. Do not worry about fancy resistors. The trick is getting the level set up correctly. You only need a little gain on the center channel. Most of the energy will be coming from the L & R speakers. Because of this, you can get away with a more modest amp/speaker for your center channel. Adjust the gain so that the center image (usually the singer & percussion) have a more "anchored" or "defined" location. While at the same time you still get the stereo image extending from the Left to the Right sides. Good Luck, -Tom
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