PrestonTom
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Posts posted by PrestonTom
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Anarchist,
Congratulations! You comments remind me of similar experiences with my own K-Horns.
Enjoy them and remember to be thankful. There are billions of people in the world, but there are only about .001 % who get to enjoy the sound of a Klipschorn.
That is a sobering thought.
Enjoy,
-Tom
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Regarding COLIN's comments.
Yes, bi-wiring (with 2 wires of the same gauge) will decrease the series resistance in the cable. A single cable of two gauges larger (16 ga to 14 ga) will do the same thing. And yes, series resistance could conceivably be a small problem when using a tube amp due to its output impedance.
However when it comes to bi-wiring, I think folks have this "model" that the electrons from one wire are "acting" seperately. No, the wires are electrically tied together at the output of the amp and again at the input to the speaker cabinet. They are not electrically isolated. I think the confusion arises because folks get confused due some ultrasonic effects that can occur (but not appreciably at audio frequencies).
I belabor the point because I beleive that manufacturers are contributing to the confusion as a deliberate marketing and money making strategy.
I am all for folks improving their stereos. However, the efforts should be directed at placement of the speakers and chairs and some relatively simple (or more elaborate) acoustic modifications to their listening rooms. This will make a difference!
-Tom
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Bi-Wiring is a very dubious proposition.
There may be some effect at ultrasonic frequencies (but not at audio frequencies). Unfortunately, it is the effects at the ultrasonic frequencies that folks refer to when trying to bolster their arguments.
The fact that the stereo salesman wants to sell you a bi-wire cable for $120 says it all.
Seriously, speaker wire should not cost more than 50cents/foot. If you must spend more money on your stereo, use the money to re-arrange your room, add (or remove) carpets, pads, and drapes. Those manipulations will have a much more profound impact on the sound.
Good luck,
-Tom
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The above is good advice.
Let me add from my own experience. If you have the "C" cabinets, there is no horizontal strip on the bottom of the fronts. If you are unlucky, when you slide them (even just a little) there is a danger of pulling the outside ply (on the bottom) away and possibly chipping it.
Again, plenty of blankets and pads.
Good Luck,
-Tom
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I will repeat what I said: My questions were not meant to be dis-respectful.
I have meade similar devices in the past that were for my own personal use - I DO NOT make these for comercial purposes.
It is interesting that a high pass circuit has been added and I know that others have made other refinements. I was trying to get a better picture of what the box does. It is obvious that there is good craftsmanship and materials involved and I believe that I pointed that out. I trust no one misconstrued my questions as an attempt to trash the merchandise.
-Tom
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Gee, I think the only stereo gear I have bought new has been CD players.
-Tom
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This is a bit off-track and I really do not mean to be dis-respectful.
The quality of the construction looks good, the box is metal (not plastic like when I make these). But unless the capacitor (a very simple high pass filter) is made out of gold ("audiophile"-grade), why is the box so expensive?
Again, I am just curious and I am not trying to get into an argument.
-Tom
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Congratulations!
That is wonderful news. I trust everyone is doing well.
-Tom
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Sputnik,
Re: dollars per pound for speakers.
I had made a mistake, the Cornwalls were not 50 cents but $2 per pound. Still it is good deal. Although the metric is tongue-in-cheek, it is not a bad one. If you look at the (possible) competition (e.g. Bose). Their dollar per pound value is not very good.
-Tom
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Tofu,
you raise an interesting possibility with the carpet on the wall. This is actually a pretty good trick and with the certain room styles the treatment will blend right in. Unfortuantely, for very low frequencies, the energy will go right through the carpet and result in realtively little absorption. This of course varies with the material, density and geometry.
Another trick to use in conjuction is to hang the carpet away from the wall a couple to several inches. (you can hide foam behind to push it out or to give a irregular coutour. This provides additional impedance mis-matches and will trap more of the sound and do it at lower frequencies also.
One caution, which sould be taken seriously, depending on the material this can be a real fire hazard to have flamables along a vertical surface. Keep this in mind whan you are designing and implementing.
Good luck,
-Tom
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I have now become better educated.
In an above reply, I sugessted that a Heresy is not all that bad of a compromise as a center channel between a pair of K-Horns. I had been doing this for the last 6 months and having reasonable success.
That is up until yesterday. Thanks to the astute eye of Rick (Thumplstilkin), I got a real deal on some Cornwalls (CW II from 1987). Yes, of course, they do a better job than the Heresy as a center channel. And the heresy is not bad, given the price they are a real deal. Keep in mind that I believe you do not need much gain on the center (since it is just giving some better "anchoring" for the centered image, and perhaps smoothing out some room acoustics).
I was surprised how much better the Cornawall serves as a center channel. Even though there is plenty of bass from the K-Horns, the Cornwall (even though it is not turned up very much) actually made the the overall low bass sound a bit more even (not that I was ever complaining about the K-Horns). Actually there were several other improvements also. I will be screwing around for the next several weeks getting the gain set correctly for the center. I love this stuff....
So if a I can retract what I said before. While the Heresy does a decent job as a center, there are deals on Cornwalls. So the price may not be that much more expensive. It is worth the difference.
Good luck,
-Tom
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I wanted to publicly thank Rick (Thumpelstiltskin).
Last week he had been checking out the classifieds and posted a reference to an ad for Cornwalls in Connecticut.
I'll cut to the chase, I picked these up on Sunday morning and have been enjoying the sound ever since. I will use one as a center for a 2 channel set up along with some K-Horns. The other one is now down in the den (the room is not set up to do a proper job for stereophonic, so a good mono is okay).
I appreciate that Rick takes the time to do this, and his efforts are appreciated.
Now if someone could explain to my girlfriend that spending Sunday morning to drive 3hours and pick up some cabinets is normal behavior even though there are already 4 sets of speakers at my house already.
I tried the strategy that the K-Horns cost me $3 per pound, so the Cornwalls were a steal at 50cents/pound. I almost ventured into dangerous territory, with the analogy that of course one needs many pairs of shoes. However, I restrained myself.
Rick, thanks again.
-Tom
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PSG,
regarding the use of a center channel.
It looks like you have the K-Horns set up properly and yes you will hear the the full sterophonic image including the centered image.
If you were to add a center channel (L+R summed), you would notice that the center (usually the vocalist and percussion) might be a bit more "anchored" - the percept is a bit difficult to describe. The term "hole in the middle" is a bit misleading since the "hole" is not absolute.
On some rainy weekend, you might try putting a center cabinet in there (even if it is a "lesser" cabinet) just to get a taste of the difference. Incidentally, the center does not require much gain.
Let us know your thoughts after you have demo'ed this.
-Tom
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K-Horns 18 ft apart
chair is 9-10 back
Thus forming and isosceles triangle (and about 2-3 ft in front of the back wall to minimize the "slap-back")
Whoops, I forgot to mention that I also use a center channel cabinet (summed L+R) to fill in the image (or else that pesky "hole in the middle"). It does not need to be turned up much, but it does make a difference
-Tom
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Hello Schorn,
I do not hve expereince with the Belles, but I have used K-Horns for the last 9 years. I have tried various power amps, Hafler, Dynaco, Harman Kardon (high current) & a Carver TFM (which I have settled on). What is it that you are dis-satisfied with when using your Adcom. Adcom is a fine amp and capable of delievering a good level of current for the transients.
The beauty of the K-Horns (and other Klipsch) is their sensitivity/efficiency along with the fact that their impedance does not drop that low. These speakers are an easy load for an amplifier. I can not imagine that you have been able to drive your Adcom to clip or distort. The only difficulty with a Klipsch is that their sensitivity wil cause them to reveal any hiss, hum or noise in the circuit. Does your Adcom do that?
If possible, you might want to try yuor friend's amp on your set up (keeping the cabinets in a fixed position in your room and with your components (minus the power amp). Would your K-Horns sound different, if so would they sound better? Comparing across set up (rooms) can be quite mis-leading since there are so many other factors involved.
Any good solid state amp (of sufficient power) may not sound all that different. Any differences will be most noticable if the signal is driven into a range of clipping, and through a K-Horn that would be deafening. If you were using Martin Logans or something else (low senstivity, impedance that drops quite low - a nightmare for any amp) then I would have a different opinion.
The biggest difference is if you dive into the world of tubes. Tube amps will typically sound different ... period. If driven hard & when they distort/clip, it will sound different (between other tube amps and especially when compared to solid state). At moderate levels (and given the efficiency of a Horn this will still be quite loud) the diiferences will be more subtle. Tubes (and this is a generalization, so don't get into a tizzy) tend to have a roll off at the higher frequencies (probably due to an output transformer, depending on the design). This (along with their faster recovery from clipping and the differences in harmonics introduced during distortion) give them a characteristic sound. If the amp is of a sufficient size, you should never hear the distortion. regardless of the level, some folks greatly prefer this characteristic sound.
Careful listening is required when comparing and blind comparison is best. You may find that the differences are not all that great.
Enough said & good luck,
-Tom
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K-Horns 18 ft apart
chair is 9-10 back
Thus forming and isosceles triangle (and about 2-3 ft in front of the back wall to minimize the "slap-back")
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I think DRAGONFYR and I are in agreement. The reason I invariably bring up the issue of standing waves in low-frequency sound reproduction is because of a demo that I always did for the new lab assisstants and visitors to the lab.
I would set up a speaker in a long, narrow room that was carpeted and furnished. I would play a low-frequency sound around 100 or 200 Hz (wavelength of about 5-10 ft). The signal would either be a sustained pure tone or a very narrow band of noise. Yes, this is not the same as music but it is revealing of some of the difficulties when you put a two cabinets and a listening chair in a room.
The listener was not confused by the location of the cabinet, so there was an accurate perception of overall direction. However, they would remark the image was not punctate but rather "large" and "diffuse" when compared to a higher frequency signal. This is not unfamiliar and is in part due to the fact the sound was continuous.
The main point of the demo was to have them walk around the room (sometimes even holding a SPL meter & mic). The variation in SPL (and loudness) was huge. Even with relatively small changes in location (less than a foot) the differences could be as much as 20 dB (4 fold change in loudness).
Now to the living room.... Now if the oputput from the left speaker, due to standing waves & comb filtering, differs from that of the right speaker than the two channels can produce very different SPLs (even the they may be similiar when measured immediately at the cabinet). This, of course, is a prime cue for directionality. In the real world of listening to music in the living room (is that the real world, hmm... yeah)I don't think we are bothered all that much because the low frequecy components are directionalized but they are "diffuse", however the rest of the signal (at higher frequencies) is both "punctate" and well-directionalized. These other regions of the spectrum are what is being relied on for the perceived imaging. I guess the conclusion is: thank goodness that music is broadband.
-Tom
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The best center channel .... is money an issue? Let's look at the trade-offs.
I use my set up for music only (no home theater) so others who might disagree may be trying to optimize different aspects of the sound. In my case I am using a Heresy center between two K-Horns
In stereophonic reproduction there will be sound that appears to come from the center (as well as other locations in between the the L & R speakers). However, when the L & R speakers are widely separated there may be a "hole in the middle". The percept is a bit difficult to explain, since there will still be a percept in the middle but it is not as "anchored" or "solid". Also the listener's sweet spot may be more narrow or fragile. I am pointing this out because in using a center channel for reproducing music, the center channel (comprising a summed L & R signal) only needs to produce relatively little SPL (compared to the L & R). Its presence should be subtle, otherwise you will decrease the width of the sterophnonic image.
I am belaboring this issue, since you can get away with using a "lesser" speaker, if money or space in the living room is an issue. Yes, the very low frequency response from a Heresy is weak. However, what is reproduced is accurate and not boomy or muddy. If you have a pair of K-Horns there will be plenty of good bass (unless there are some room acoustics issues, which is also quite possible). So the center should not have to augment the low bass. It is only "anchoring" the perceived imaging in the middle. Obviously a better speaker is preferred (CW, Belle, or LS) but that might not be practical. BTW, the center may also get rid of some frequency anomalies (comb filtering) or at least smooth them out a little bit. And it can also provide a better top end since the the higher frequencies from the L & R speakers may be a bit directional and not adequately aimed at the listnener.
Again, my comments do not apply to HT, which seems (and I say this in a friendly way) to exaggerate certain aspects of the sound (huge image, chest pounding bass, etc).
If you currently have a lot of gain on the center, try cutting back a bit, You may also notice an increase in the appearent depth of the image also (IOW, Let the K-Horns do their job).
Incidentally, having said all this, I may be picking up a pair of Cornwalls this weekend and using one as my new center (I may be getting a deal that I can't pass up. It really is a sickness!)
Good luck,
-Tom
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I will have to confess my ignorance and perhaps DRAGONFYR or whoever can help me out.
First question: if the supplied voltage goes low then wouldn't you have to use something like a baterry or a very large capacitor to effectively buffer against these dips in voltage?
Second question: when the voltage goes low, doesn't the transformer and the large capacitor in the power supply portion of the amplifier provide buffering for transient decreases in the supplied voltage?
I always get worried when manufacturers make money from audiophiles who may be ignorant of the specifics.
This is my paranoia, but I am also curious,
-Tom
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I think we are listing our favorite speaker and ignoring the cost.
Naturally I would vote for a pair of K-Horns. However, if I were younger and had no money, I would think that a pair of Hereseys with a sub, would be a sweet little system.
-Tom
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Although I agree with the above comments, please remember that with wavelengths this large (regardless of the cutoff) the SPLs that you are going to hear (at your chair) are highly dependent on room acoustics. Even at 100Hz the wavelength is about 10 ft and these low-frequencies are (relatively) unaffected by furniture, carpet and drapes. So the (appearent) directivity and level will be more affected by the geometry of your room & placement of the listening chair. At 100Hz and lower the directionality is not strong and typically there will be little stereo separation (i.e., the signal wil be similar in level at each speaker but will probably interact differently with the room geomerty).
Good luck,
-Tom
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Good Luck with an interesting project.
As you point out, you are assuming that the components are spectrally flat. This is probably not a bad assumption, except for the speakers (and how they are set up in the room).
The probelm is a tricky one (that is why I think it is an interesting one). Although I don't agree with the tone of voice, DRAGONFYR is quite correct in anticipating some of the problems - and I whole-heartedly agree that it much more than an issue of getting an EQ unit in the circuit.
Dr Who has a more optimistic approach and I appreciate him taking the time to share his knowledge, since I enjoy learnining about this also.
The basic issues are that in a frequency domain perspective, temporal aspects of the reproduction are being ignored (by necessity and by assumption). In this regard a direct sound & its reflection are not distiguished but rather they are simply summed and the result is standing wave and comb filtering. Simply trying to equalize your way out of this is not a good solution. To a certain extent, attentuating the reflections or making the direct sound more "directional" might help but it is incomplete.
The time domain solutions are an alternative. In this case, a primary sound and its reflection are not highlighted as a standing wave or comb filtering, but rather as an echo and reverberation (I am using a crude approximation). The solutions may be similar (non-reflective surfaces, traps, placement of chairs and speakers etc), but as was pointed out the key is determining whether an anomaly in the output of the RTA, MLS etc is a big deal or not. That is, which "dip" needs to be fixed. As I understand things, that relation is not well-understood so a bit of experimentation will be required (not all reflections are deleterious to "good sound"). The other difficulty with the time domain approaches is that they are much more recent inventions (compared to Fourier which has been around for a long time). I think less intuition and common tricks of the trade have been developed.
Good luck and let us know how it goes,
-Tom
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I was a bit surprised to see negative comments about Crown amps.
I have used these in a few different labs over the years. They have always sounded great, looked good when we checked via scopes and spectrum analyzers. They are also very well built (or at least they used to be)
-Tom
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Hello Priapus - it looks like a journey is about to begin. You mentioned suggestions for classical music and the answers have ranged from Baroque to the Romantic eras. This is why the question is a difficult one. I would suggest a trip to the library and simply try sampling from the different eras (Baroque, Classical & Romantic) to start with. I would also try different formats (symphonic, concerto, & chamber music). One source of advice comes from National Public Radio. They have put out some lists on the "essential 100) etc. These are pretty good.
Good luck, but be forewarned: it's addictive,
-Tom
speaker wire gauge
in Technical/Restorations
Posted
Guys,
I came in late on this one. The calcualtions are probably okay. But I sincerely hope none of you are worried about the audibility of a 1 (or 1.5) degree phase shift (esp up at at 20kHz).
-Tom