PrestonTom

Regarding Shawn's comment about my comment (it gets confusing) ""The summing was done early in the circuit of the "center" pre-amp and all the L&R's were tied together and "went back" to the "stereo" pre-amp. The stereo separation was lost." ......... Any of these passive approaches reduce stereo seperation and placement. You no longer have the ability to reproduce hard right and hard left in a mix... it will be reproduced as right and center or left and center. " I was referring to to folks inadvertently summing all the inputs with y-cords & sometimes multiple preamps (can easily be checked with a VOM meter). The issue of decreasing the stereo seperation with a passive device should not be all that problematic. I built the Klipsch-version, the seperation is still about 30 dB (measured at the output of the box). This is plenty to get the full stereo spread. This of course will be decreased if the volume on the Center channel is turned up too much. It should be a few to several dB down from the L& R speakers. Good Luck, -Tom

I also agree with the other responses. BTW, there are some less than cosmetically perfect Chorus 2s offered in this link http://www.robertsav.com/usedequip.html These are on consignment. I have no business/financial connection with the dealer. I will say, however, I have purchased a number of used items (including my K-Horns) from them. I have always been well-treated. Good Luck, -Tom

Steve and others, The mini box is pretty simple and inexpensive. I would urge you to make sure it includes an audio pot so you can more precisely set the level. As Al implied the level for the center does not need to be very loud, certainly not as loud as the L & R speakers. I am leery of using Y-cords to create a summed center. Depending on the configuration, it is possible to get a summed signal to connect to the extra (center channel) amplifier and at the same time you can inadvertently end up also sending a summed (mono) signal to the left & right speakers. I have seen folks do this when using an extra pre-amp set on 'mono". The summing was done early in the circuit of the "center" pre-amp and all the L&R's were tied together and "went back" to the "stereo" pre-amp. The stereo separation was lost. Good Luck, -Tom

Hello MrB, The definition of "boomy" probably means different things to different people. However, various aspects of the bass should have changed when you moved the K-Horns out of the corners. I assume they were tight in the corners initially. If the "boominess" is dramatic (not subtle) I would not worry about amps, crossover (if it works correctly) and wiring. However, I would direct your attention to the source material since the K-Horns should have a very accurate bass reproduction (is the source/recording "boomy"). Further, and this is more likely, I would try changing your listening position to see if this changes things. I mention this because room acoustics are a very likely culprit (esp for frequencies below 400-500 Hz). God Luck, -Tom

This is indeed a curious question, but a difficult one to answer since they are two very different speakers. It is curious since I have both K-Horns and ML Aerius at my house. The K-Horns have big dynamic sound with a very accurate bass. Because of their efficiency they are easy on an amp (if it is quiet) and will reproduce any flaw in the recording and other electronics. On the down side their imaging is far from perfect (while it is not bad & most speakers have this problem anyway). Also the the midrange has some problems. If it has not already been stressed: they must be placed in a corner (or false corner). On the other hand, the ML Aerius (I assume your candidates are roughly comparable) has imaging that is fatastic and a mid-range that is superb. They really do excel on these two counts. On the downside, the bass is weak (mine are a hybrid design) and they do not have the dynamics when played at a high volume. "dynamics" is a vague word to some, but you will know what I mean if you listen to them side-by-side. As pointed out by others, the MLs require a big amp that is capable of providing high current. Without a sufficient amp, the problems with the bass and dynamics will only be magnified. Not noted by others, the MLs (and other panel speakers) are tricky to position in a room. Positioning them is worth the effort however. I picked up the MLs as a second system for the den with the intent of listening to mostly small ensemble classical, baroque, and early music and some folk. They do that very well. But there is more I like to listen to... Eventually I will get rid of them since they take up much space in the room (they have to be located several feet away from rear and side walls). Good Luck and I would interested in hearing your thoughts once you get a chance to listen to them, -Tom

Hello Pete, Someone suggested reversing the phase on one of speakers if you go the the long wall. This is absolutely incorrect. There may be some added diffuseness to the image when the phase is reversed, but this is just a gimmick. Overall, this would be a bad idea. Good Luck, -Tom

Hello Pete, DrWho makes a good point about the listening position. Ideally, the face of the Khorns should form a perpendicular to the listener. So if they are seperated by 22 ft, then the listening chair should be 11 ft back. Since your room is 15 ft this actually lets you pull your chair away from the back wall a little bit (this helps minimize some of the "slapback"). The stereo image will be quite wide (a 90 deg spread). As noted the middle may need to be filled in with a summed center speaker. If you do this, and it is a fun experiment, the center need not be turned up all that much. As an experiment, you can substitute a lesser speaker to get a ballpark idea of the effect. The recommended geometry (in your case, 22 ft apart with the chair 11 ft back) has another advantage that is not always mentioned (I was recently reminded of it in a DFH article). The sweet spot will be larger. Additionally, the frequency response will be more even since you are on axis with the horns. Also, by adding the center channel, some problems with room acoustics can be cleaned up (sometimes). Good Luck, -Tom

Some comments were made about inroducing distortion with such scheme. I would also be worried about that. However DrWho (who seems knowlegible) stated that the signal path would still have as many elements in the chain (passive crossover vs active) and that active crossover would have less distortion. Well, this is shock to me. First, there is absolutely no need for big amps (and are the big amps necessarily going to be quiet enough for these efficient speakers). Second, there would be many new pieces in the signal chain: ADC & DAC conversion, various op amps etc. Third, I cannot believe that running a signal through some passive devices (inductors & capacitors) would produce relatively more distortion (these are "quiet" components). Clue me in guys.... Good luck, -Tom

I think we need abit of a reality check here. First what is it you are trying to fix, and more importantly does it need to be fixed. In applying the convolution there will be a time delay in itself. This, of course, is proportional to the number of delay-slide-multiplies that one is performing (utimately a function of the number of taps or the steepness of the filter). Is the entire signal (across the entire bandwidth) being delayed followed by an additional delay in the band of interest? Second, is this being done because of the additional delay during the transduction with the frequency components through the bass bin (and its various folds). If this is the case, then you may want a steeper filter, since a simple, low order Butterworth will have appreciable overlap with what is going through the mid-range horn (I will ignore the fact that the crossover itself creates relative phase delays - which are probably incosequential - except where the spectra overlap between the 2 drivers). Third, be careful with the zero padding (the 3 ms of silence). This deserves attention regarding what windowing or gating is applied. If you do not know what I am referring to, you need to do some homework. I hope what I am conveying is that this DSP is tricky business and not as straight forward as you might think. However, I am interested in what you come up with. In aswer to my other question - does it need to be fixed? Take this as a grain of salt, since there will possibly be sonic consequences when you start putting the signal through extra stages (op amps , ADC/DAC, reconstruction filters etc). Good luck, -Tom

An interesting swap. The sound will be quite different. Regarding the maggies ( I do not know which specific model you are getting). The bad points are 1) the mylar can tear (it sounds like these already have) but it can be patched or replaced (if required), 2) the bass will not match a Klipsch, 3) they require a big amp with plenty of current, 3) as with other panel speakers, they are difficult to position in the room (tweaking in the placement is required) However, the good points are quite strong: 1) the midrange (and highs) are really very good (certainly different than a klipsch), 2) the imaging, if positioned correctly, is superb. They are worth listening to but beware of the positioning and amp issues before make a final decision. The sound is different that a Klipsch. They each have their own set of pluses & minuses. Good luck, -Tom

Rudy, There is some confusion in the responses since the thread actually goes back several months. In answer to your more recent question about tiling the the insides of the false corners .... I would imagine this is simply an aesthetic issue. I assume you used one of the prescribed construction methods. In that case there is sufficient mass and stiffness so the unit will not be vibrating. The tile would add a a very dense layer; however, there is already such a large impedance mismatch (air-to-MDF or air-to-tile) that I do not think it would create any additional benefit. Good luck and post some photos when you are done. This is such a fantastic project for folks with less than ideal rooms, and the results and benefits are quite dramatic. -Tom

I don't disagree that horns are not necessarily an easy speaker to postion and drive. The difficulties are different with a panel speaker. I have had more difficulty with driving an inefficient sepaker with a low impedance compared to a "wild" impedance of a Horn. Regarding placement: all speakers probably have their difficulties. However, with panels speakers the difficulties are huge. I will confess however, I love my K-Horns. But the midrange and and imaging on a panel speaker can be out of this world. I have yet to achieve that with my K-Horns. This is not a controversial statement and it is not baiting. Believe me, I love the K-Horns. There are certain things that they do very, very well. But they are not strong in every area (no speaker is ...). Panel spaekers can be fun to listen to ... Good luck, -Tom

Michael, This is perhaps putting the cart before the horse. I recommend first determining what portions of the spectra you are most concerned about. Foam is a bit tricky but there are some rules of thumb. The foam will have absorption coefficients listed, preferably the entire function (absorption as a function of frequency) will be listed. In some cases there will only be a single number listed (e.g. NRC weighted average), this may or may not be useful. The foam mave have a wedges carved into it. This will extend the effective bandwidth over which it absorbs (to the lower frequencies) First, if the foam is shaped into wedges, the depth of wedge will deternine the lower frequencies that will be effectively absorbed (this is a relative statement). As a rule, the wedge would be about 1/4 wavelength (1000 Hz or 2 octaves above middle C) is about 13 inches for the wavegth so the wedge would need to be at least 4 inches in depth. Spinning through this fact, foam or fiber glass wedges are not very good for lower frequencies since they would be incredibly large. Second, how the material is mounted does matter. The absorption coefficients listed should specify this (frequently for home material they do not bother). One trick is to mount the material on some sort of drape/sheet and space it away from the wall. This can help the material absorb even lower frequencies (to an extent). How ever the trick is most effective if the spacing is 1/4 to /2 wavelength. Again, this limits the practicality. Foam is not the only solution: cloth, drapes etc can also help. The problem is how to tame the low frequencies. This is where annoying standing waves come in to play. Low frequency waves are large and will effectively "not see" the material. There will be little absorption and little "breaking up' of the waveform. In this case the solution is a large space and physical devices like wave traps and resonators. This is more elaborate and there is a degree of tuning required. The WAF is especially tricky. Sometimes speaker location and furniture can help (not by eliminating the standing waves, but by moving them in their in location or frequency). However imaging could be impacted. My advice is to do the homework ahead of time since the solutions (esp at low frequencies) can be costly. For the mid and high frequencies, try tacking up some old carpet on various positions on the walls, ceiling and extra (or less) carpet/pads on the floor. This will give a rough approximation of what might be gained with room treatment (or a reange of frequencies). What is sometimes neglected is that a room entirely devoid of standing waves/reflections is not necessarily the goal (anechoic chambers do not sound very pleasant). Besides that goal would be very expensive. Usually folks want to tame reflections in certain areas to the mid-range so that imaging is more accurate (along with taming some spectral problems). In extreme cases, reverberation may also be excessive. Usually, folks are most concerned with the low frequencies, so the the bass has a more uneven response. Again, this region is the tricky and expensive one. Note, at no point have I mentioned the use of an equalizer. If one is used, is should be done after the room treatment is complete, used sparingly, and not used to even out majpr probelms at the very low frequencies. In my opinion ... Good luck, -Tom

Those Maggies are fun to listen to. You can find them very reasonably priced, since they were the entry-level version. They are hard to drive however. The impedance is low and the sensitivity is miserable. The other negatives are that they do not have a loud & dynamic sound and the bass is very shy. The last negative is that it takes a great deal of fiddling around to correctly place/locate them in a room. That is a long list of negatives. However, they have a wonderful mid-range (actually it can be quite remarkable if they are positioned correctly) and the imaging/sound stage is astounding (again this requires proper placement). It is in this regard, they differ the most from the Klipsch/Heritage-sound (along with the bass). They are nice to have as a back up system if your home allows for that. Beware when you buy this used however, they do get tears in the mylar (usually fixable). Good luck, -Tom

Lynn, That is very disappointing news. This must be a very anxious and frustrating time for you and your family. My prayers are with you. Best of luck, -Tom

Gee, after I asked about why one needs 200 watts of power to drive a K-Horn, the comments have become murkier. One responded that the 200 watts gives the necessary headroom. Given the efficiency, that is quite a bit of headroom. A second person responded that not only is the extra power needed, but the amp should also be capable of high current levels. Yes, I have used high current amps for driving speakers that drop to low impedance (esp at low frequencies) ie, 2 ohms. But K-Horns do not present that problem. Given the efficiency and impedance of the K-Horn, this has become an interesting topic. Good luck, -Tom

AMEN!!! -Tom

Coytee, I also have K-Horns, so I will interested in the repsonses that you get. However, let me ask an innocent question: Why in the heck would you need 200 watts of power with a speaker that is so efficient? Seriously, is it likely that an amp will be both clean sounding, dead quiet and also have that much wattage. My limited sampling has indicated that the efficiency of the K-Horns is ruthless in revealing any hiss, hum or distortion in an amp (or pre-amp or source). Good luck, -Tom

It is important to pay attentuation to what Marvel said. The cable from the pre-amp to amp will have a small amount of capacitance (especially if it is not short). Changing the resistance by swapping the pot or adding resistors MIGHT inadvertently produce a low-pass filter (single pole with a corner at 1 / 2*pi*R*C). The output impedance of the pre-amp and input impedance of the amp are not arbitrary. Good luck, -Tom

The old advice is still true: The speakers will make the biggest difference. The CD player will make the least difference. The "misc" (speaker wire etc) will make no difference. The amp is tricky. If it is large enough (depends on whether the speakers are efficient and do not require much current - i.e., not low impedance) then most solid state amps will sound fine (if it adequately sized and it is quiet). Tube amps will have a different sound - some folks prefer that sound. For loud music in a large room, then choice of amp may be trickier to find one that is adequately powerful (unless the speakers are an easy load). Note, this not simply a matter of Watts - there are also issues of headroom and being able to provide adequate levels of current (again depending on choice of speaker, listening preferences and room size). Focus on the speakers! Then the effort should be spent on setup (this is not always expensive). They should positioned carefully (and this can take quite a bit of experiementation - but the effects are real). After this spend your energy on treating the room. Invest some time in learning about "room acoustics 101" and then tackle the listening room. Issues at mid and high frequencies are more easily taken care of (carpets, drapes, carpet padding, furniture set up etc). Issues at lower fequencies are more difficult and may cost a modest amount of money (but please educate yourself first). These are not "sexy" solutions, and others will disagree. However the effects are real. Small changes in speaker location and room set up will yield very noticeable changes in sound. The trick is determining whether the changes are for the better - it does take tweaking and experimentation, and most importantly, some time spent educating yourself about room acoustics. Good luck, -Tom

Re: Using a "passive" pre-amp with a ss amp. I have bee doing this configuration with an Adcom straight line controller (passive pre-amp). One thing that is sometimes missed is that the output impedance of the passive preamp is not as high as a typical pre-amp. One consequence is that a long interconnect from the pre-amp to the amp, can acually introuduce some low pass filtering, since the input of the amp is typically configured to "see" a higher impedance input (this is a folksy explaination) from the pre-amp. The corner freq of the this "filter" would simply be a one pole filter (6 dB per octave) located at 1 / (2*pi*R*C). In this case the capacitance would come from length of the cable. This is generally very small (and typically ignored) and it is specificed as capacitance per length of cable. It is best to use a cable shorter than 2 ft. This is a real effect and not "cable voodoo". I am not advocating using some expensive & esoteric cable. A typical interconnect, if it were 3ft long, might actually low pass the signal at 13-14 kHz. The solution is simple, make sure your cable from the passive pre-amp to the amp is short. Good luck, -Tom

Gee, those were two absolute giants! I bounce back & forth on listening to those old recordings. The music is incredible but the sound is sometimes problematic ( I know, it's about the music). Some of these recordings have been cleaned up pretty well and that helps. Actually, after listening fo a couple of hours, you seem to adapt a bit. Maybe some day I will pick up a used DBX or Carver AUTOCORREALTOR. Those devices helped as I recall, but I am shy about ading extra pieces in the circuit. Wait, it is about the music .... Good Luck , Tom

Danny, Congratulations! I enjoyed hearing your story. Those K-Horns look absolutely fantastic. Good luck, -Tom

Jeremy, keep up the upbeat mood. There is an end in sight! I have a silmilar problem. My listening room is next to my kichen. The kitchen is undergoing a rennovation and many supplies etc are now in the listening room (which is aslo covered in dust, regardless of the various precautions). With boxes and tools piled everywhere I have not been able to listen to my K-Horns in the last 3 weeks. The kitchen re-model started out as: "why not build a center island" and morphed into tearing out all the cabinets, new underlayment/ceramic tile floor, upgrade on electrical and some plumbing, paint, trim etc (it is 450 sq ft - so all the headaches and expenses are multiplied upwards). It is going to look good when it is done....that has become my mantra. Thank you for letting me commiserate. Good luck, -Tom

This issue of the "loudness" knob comes up periodically. And when one looks at the logic of it, in fact it does not make sense given a certain assumption. Stereo reproduction at a low level will (and should not) not have much perceived bass. Live music at a low level (perhaps at a great distance etc) will also not have much preceived bass. The assumption (and one that I subscribe to) is that the the goal of the reproduction is accuracy. In simple words, does it sound like the real thing or can I close my eyes and get a sense of "being there". There is no "volume" knob (or bass enahncement) in the real world. The Fletcher-Munson curves are real. The bass is not very "loud" at low levels, why should it be so on our stereo in the living room? Paul is absolutely correct given the above assumption about the goal of accuracy. I agree with him. I will confess; however, that on occassion when I can not turn up the level I will resort to a "loudness" knob. Good Luck, -Tom