Deang

No, no...do your thing with the Scott. This is for the Apollos, which currently have Hovlands in the coupling cap positions.

Bi-Wiring 101 - BY JON RISCH In order to explain how bi-wiring works, it is necessary to explain a bit about how crossovers work. It will also be necessary to contemplate more than the usual voltage output of the crossover sections, so do not assume that if you know the basics for crossovers, that you will know what this will be all about. Let's look at a simple two-way system with a first order crossover, the simplest crossover and system we can examine. It will be relevant to other more complex systems, so once you understand this one, the others will fall into place. We will not address the issues of tweeter level padding, response EQ, etc., just the basic crossover function itself. In a simple first order crossover, there is an inductor in series with the woofer, and a capacitor in series with the tweeter. These two components comprise the crossover system. Normally, these two components are connected to the same input terminals on the speaker, in parallel. Hence this type of crossover topology is called a parallel type crossover. A full range voltage signal is sent down a speaker cable, and appears at the single pair of input terminals. A current is drawn based on the input impedance of the speaker system as a whole, which in most cases, will have a relatively flat impedance curve once we get above the bass resonance region, where the impedance will be dominated by the cabinet design resonance's. If we say that (for purposes of this discussion) the overall impedance of the speaker in the midrange and on up is relatively flat, then a consistent amount of current will flow through the single speaker cable all across the audio band. So there are several elements to the total circuit formed by the amp output terminals, the speaker cable, and the speaker system and crossover network. A signal appears at the amp terminals, represented by a voltage, the impedance of the speaker system causes it to draw an amount of current proportional to it's impedance for a given drive voltage, and this current flows through the speaker cable. Now in order to examine what happens when we bi-wire, it will be necessary to go into some of the detail as to how a crossover "crosses over". If we look at just the woofer, and it's series inductor, the inductor provides little impediment to low frequencies traveling through the inductor, and a high amount of impediment to the higher frequencies. Looked at another way, the inductor impedes the highs but not the lows. If we examine an impedance curve of just the woofer with its series inductor, we would see that the impedance was pretty much just that of the woofer in the low frequencies, and would rise with frequency as the inductor impeded more and more of the highs. For this situation with just the woofer, for a given voltage drive level, a certain amount of current would be drawn at low frequencies, and this amount would decrease as the frequency went up, due to the rising impedance. If all that was hooked up to the amp was the woofer and it's associated inductor, then the current flow in the single speaker cable would follow the impedance curve, a certain amount of current flow at low frequencies, tapering off at higher frequencies. Perhaps a glimmer of the true situation with bi-wiring is beginning to appear. Now let's just look at the tweeter, and it's associated capacitor in series. At low frequencies, a capacitor tends to impede the flow of current, and at high frequencies, it provides little impediment. Hence, when we hook up just the tweeter and it's capacitor to the amp terminals through the single speaker cable, there is little current flow at low frequencies, and an increasing amount as the frequency goes up. At some higher frequency, the current draw is determined by the impedance of the tweeter alone. Now just to make sure that it is understood, it is the current flow through a dynamic driver (one with a magnet and a voice coil) that causes it to move. A voltage applied that had no current capability would not cause any movement. This means that in order for the voltage at the amp terminals to cause a speaker to move, it must have a relatively low source impedance, so that when a given voltage appears at the amp output terminals, a given amount of current can flow into the load's impedance. That is why when the crossover components impede the current flow, they cause the output of the driver to drop off, hence the crossover function is achieved. Note that the woofer and it's associated inductor, and the tweeter and it's associated capacitor will function independently, they roll-off the frequencies out of the driver's operating band without regard to whether or not the other half of the crossover is present or not. When both sections of the crossover are present, and connected in parallel, the overall impedance curve looks relatively flat, as when the tweeter section has it's impedance going up in the low frequencies, the woofer has it's impedance going down. At the crossover point they are more or less equal, and this is the point in frequency at which the impedance's of the two sections in parallel equal approximately half that of either section alone. This is how two 8 ohm drivers can be connected together through a crossover, and not equal a total load of 4 ohms. By now, you should be getting the idea about bi-wiring. Instead of one speaker cable, or just one of the drivers and it's associated crossover component being connected to the amp's output terminals, two separate speaker cables are connected to the same amp output terminals and run to the now separated crossover sections. With different impedance's being presented across the audio band, each cable carries a different signal than a single speaker cable. The separate cable for the woofer carries mostly the LF currents, and the separate cable for the tweeter carries mostly the HF currents. This is due to the differing impedance's we discussed above. Now if all you think of is the voltage at the amp terminals, and how the two cables are carrying the same voltage to the woofer and the tweeter sections, then it still may seem that the same signal is being delivered to the drivers as through one speaker cable. IF the speaker cables were perfect, and had zero impedance, infinite mass, and no digressions from ideal LCR behavior (DA, DF, hysterisis, etc.), then it may be that this would be the case. Since the cables we have available to us are not perfect, there are losses in the cables. The $64,000,000 question is, how much does the real world speaker cable compromise the performance of a speaker compared to bi-wiring? To make this easy to figure out, we will ignore the effects of inductance and secondary effects, and focus strictly on DCR effects. Let us assume that a cable sufficiently large enough to keep speaker system impedance variations from affecting the amplitude response by more than 0.1 dB was used, meeting the Krueger criteria. In many cases, this is a very large cable, usually at least a 14 gauge, and often 12 gauge OR LARGER. For a copy of the Krueger criteria see: http://x42.deja.com//getdoc.xp?AN=450322078&CONTEXT=927059192.1901920287&hitnum=6 (I should warn that I do not agree entirely with Arny's criteria, it completely ignores inductance, which typically gets worse as a ratio of DCR to HF impedance of the cable as the gauge gets smaller, or larger zip cords) How quick do the gauge requirements add up? If you have only 10 foot cables, and a speaker with a minimum Z of 6 ohms, then a 14 gauge wire is necessary to prevent any more than a 0.1 dB amplitude variation due to the cable DCR. If the speaker Z minimum hits 3.7 ohms, you are now up to 12 gauge. Anything longer in terms of the speaker cable, or lower in terms of the Z, will require larger than 12 gauge to reduce the amplitude variations due to voltage drops to less than 0.1 dB. See: Bi-Wiring Attenuation of Inter-Driver IM If we were to look at the simple change in DCR from merely doubling up on the cable, then distortion would only go down 6 dB, from halving the DCR and nothing more. Of course, once we start using real music, with more than just two frequencies, and real world cable situations that might have even more DCR, and the inductance differences between a single zip cord and two high performance speaker cables, the amount of distortions in a single speaker cable go up considerably, and the amount of reduction in distortion is increased for the bi-wire comparison. This means that we might be into 2% IM or more, and with multiple frequencies, which make it even worse sounding. All of the above totally ignores any potential magnetic field interactions, many of which would be time delayed and would smear out transients and large signals. The magnetic field distortion reduction would come from the separation of the LF currents and the HF currents. The time delayed and resonance associated signature would tend to make these distortions even more noticeable than the self-IM of the cable due to voltage drop. I think it is easy to see that a multidriver system with higher order crossovers will react similarly to this very simple first order two-way system that has been analyzed. It is interesting to note that higher order crossovers tend to have a similar input impedance for each section as a first order, and it is the output signal of the various sections of the crossover that are made to roll off steeper. In essence, the reductions in current for each cable in a bi-wire pair will be at a 6 dB/octave slope almost regardless of the crossover order. Last ditch explanation for those who still don't get it. Assuming that you have read the above information, and have the beginings of an understanding of how a crossover works, and how it divides the frequencies to the speakers, lets try this: Traditionally, a crossover cirucit for the woofer, and a crossover circuit for the tweeter are hooked up together inside the speaker (wired in parallel, hence the term parallel crossover is used for this type of network) and one set of terminals are present on the outside of the speaker box. In a bi-wire capable speaker, these two crossover sections are electrically separated, and a separate pair of terminals made available on the back of the speaker, one pair for the woofer, and one pair for the tweeter. At each one of these separate pair of terminals, the LOAD seen by the amp is different: for the woofer, the majority of the LOAD is in the bass, with little loading in the treble for that separate circuit and driver. If you hooked up just one cable to the woofer terminals, then the current draw from the amp would be almost all in the bass region, with little or no current draw in the treble region. The woofer crossover is high impedance on the input to the woofer at high frequencies, and hence does not draw very much current. Compared to the traditional speaker system, with it's two crossover sections in parallel, this single cable to just the woofer section would only tend to draw current from the amp at low frequencies, while the full range crossover would draw current all across the audio band. If we were to hook up a speaker cable to just the tweeter section on a bi-wired speaker, then this connection would draw very little current in the bass, as the tweeter crossover would be high impedance in the lows, while in the highs, where the tweeter provides output, there is some current being drawn from the amp. Again, just the tweeter section of the crossover and the tweeter only tend to draw significant current in the high frequencies, and very little in the bass. Now, if we hook the two sections back together AT THE SPEAKER, we have essentially provided the traditional speaker/crossover hookup, and the single speaker cable will once again carry current at all frequencies, not just the bass, or not just the treble. HOWEVER, if we run a separate speaker wire to each of the bi-wire terminal pairs at the speaker, each cable will now carry a different signal than a single cable, as the load at each pair of terminals, the woofer pair, and the tweeter pair, is different. The cable from the amp to the woofer will carry a lot of current in the bass, but hardly any in the treble region. This is a direct consequence of the way the crossover functions, and the fact that a dynamic speaker needs current to work. Note that even if the cables were zero resistance, and zero inductance, etc., they would still carry different signals, due to the differing current draws vs. frequency. This ties in with the diagrams at: http://www.geocities.com/jonrisch/page9.htm Which shows first the current draw of a single speaker cable, and then the current draw through a set of bi-wire cables connected to the same speaker, only bi-wired. Because real world speaker cables do have some resistance, and do have some inductance, they will exhibit voltage drops bassed on this current flow. The voltage differences would be quite small for low DCR/low inductance cables, but still present nonetheless. The variations in the voltage portion of the signal may be -40 db or -50 dB or more down, but this is not as low as one might think, and since the IM distortion that would arise due to bi-wiring is not at any single frequency, but will be occuring at many different frequencies. This raises the potential audibility of the total amount of IM that occurs, and makes it more likely to intrude into the musical presentation. Again, see the web pages I reference. There is no doubt that differing currents are flowing in the two cables of a bi-wire set-up, and since current flow sets up a magnetic field, and magnetic fields interact with current flows, the oportunity for IM and other deleterious interactions is present. The IM part has been measured, and I present this on my web site. Start at : http://www.geocities.com/jonrisch/page7.htm Perhaps this will all make more sense to you now.

Sub placement is the same for all subs, just find a good corner. One thing nice about the SVS, is that though it is fairly tall -- it really has a fairly small footprint. I'm selling my 20-39CS Plus. It's running in an ad below. You don't see them up for sale often, and for good reason. However, I'm moving to big 'ole horns -- and need the money to finance the venture.

I'm NOT doing this. I ran across the blip while searching for a possible, suitable replacement mid-woofer for the DQ's. I was simply wonder what, if anything, you all thought about the comment regarding the original driver not being designed to run down below 700Hz. See my PIO post. After spending considerable time stumbling through the Asylum archives -- I'm completely confused.

Ran across this at Layne Audio. Steve knows his stuff, but was wondering what you all thought about this: Midrange driver : We have located a very high quality replacement for the old EV / Atlas / University drivers found in the classic Klipsch horn loaded mids, only $69 each, this driver is built more heavily and can take the low crossover point <~450Hz> of the larger Klipsch speakers without distorting. The original drivers should really never be run below 700Hz, as a result the lower midrange lacks detail and can be quite distorted, especially at higher volume levels. Our new driver has usable response down to 400Hz , and is rated at 120w RMS crossed over as low as 500Hz. These also use the older type phenolic diaphragms to maintain the "classic" sound lacking in most modern drivers, which almost universally have harsher sounding metal diaphragms.

Original boxes, manuals, and Better Cable interconnect. Mint condition - like new. Paid $975. Save $250. $725

Original boxes, manuals, and Better Cable interconnect. Mint condition - like new. Paid $975. Save $250. $725

Original boxes, manuals, and Better Cable interconnect. Mint condition - like new. Paid $975. Save $250. $725

Just got done surfing the Asylum archives for the last 3 hours and my back is killing me. I read about 1000 posts about PIO's, and it was certainly love or hate with these things. 1000 posts all saying the same thing. Very informative stuff. They suck. No they don't. No highs. Great highs. Rolled off. Natural. No detail compared to Hovlands. Hovland detail is 'fake' detail (whatever in the hell that means) Muddy. Liquid. What B.S. A complete waste of time. So, anyone here want to offer more insight than I got from the loony bin?

Doesn't sound like I even had you remotely convinced Damn, I'm losing my touch.

Well, I'm not really a wuss, I just think it's wrong to take advantage of someone's mistake. At any rate, trust me on this one -- there's no way they would've sent these cables out without credit card number and payment. What? You think these people are idiots? At any rate, as far as the other thing goes -- the ball hits the glass and I'm outta there with everyone else.

I offered $265 and he took it.

Oh yes, I totally agree with the both of you. I KNOW the Heresy is not a Cornwall, but I wanted to make sure it was understood that the RF5 is NOT an RF7 either! I do know that while Klipsch engineers were voicing the RF7, there were sessions comparing the RF7 and Cornwall. I am VERY interested in seeing where the Cornwall parts company with the Heresey, and the RF7. Nothing I hear however, is going to make me dump the RF7's -- they are truly excellent. Incidently, for all intents and purposes I have bought some Cornwalls. Jeff was so kind as to let me nickle and dime away at his until I pay them off. It will probably cost around $1000 total to get them to my doorstep, and I'm halfway there. I'm hoping to have them in the next couple of weeks. I didn't need the cottonballs for the Heresies, so I think I'll be alright with the Cornwalls.

I received an email from Jason, who works at Music Direct, asking me what length and terminations I wanted. I sent a reply to him that I didn't really expect to get these cables for $6.00 -- unless they were running one hell of a Christmas Special. I told him about the error on the page -- and that several of us were just jerking his chain. I can't believe you guys actually BELIEVED they were going to send these cables out, or that it was really O.K. to expect them to do so. These are the businesses that support our hobby, and they do it because like us -- they enjoy the music. If they would have shown up on my doorstep, I would have crapped -- and felt terrible. Which is pretty much how one feels with crap in their pants.

I do believe he just bought some Cornwalls.

OTOH, I've found all those knobs and switches to come in quite handy! It's nice to back that treble down to -2 when the Heresies start screeching with the dial on 6, or to be able to make minute adjustments with the balance control knob. I think all those crazy knobs are part of the overall circuit that contributes to the final sonic signature of the piece. Inane babbling, sorry. The biggest conern here is buying vintage without having it serviced, to remedy safety and performance related issues.

Now, now, y'all keep your pantyhose on and don't get yourselves all worked up:) I'm telling they both sound great, and each has inherent strengths and weaknesses. I don't know where the RF-7's were auditoned at, in what room, or associated equipment -- but I can tell you the 7 is not the 5 -- not even close. The horn on the 7 is a monster, and is more like a pro-style driver than what is used in the RF-5 and below. I can tell you that life with the Heresies has been great. I believe they have more clarity than the RF-7's, are crisper -- and deliver a more articulate sound at low to moderate listening levels. However, they pinch up rather quickly -- and aren't all that pleasent to listen to at 95db and above ('true' 95db at the listening position). There is more compression than with the RF-7, they are not nearly as dynamic, or have as much resolving power when it comes to low level detail. In spite of this, the Heresies are an extremely musical speaker to listen to -- and I have trouble pulling myself away from them. I understand that the Heresy is not the Cornwall, and I'm sure the Cornwall will do better with higher SPL's, but I'm also sure the Heritage signature will remain intact -- and I believe overall, the Cornwall will succumb to some of the same problems as the Heresy (compression). I do believe that Heritage, like any speaker -- benefits from some toe in. I've got my Heresies throwing a nice stable image -- with dead on center voices. The RF-7's can be driven to insane levels with no discernable compression, maintaining their signature regardless of volume level. They image better than the Heresies -- not just throwing a nice side to side soundstage, but front to back as well. Though not as crisp or clear as the Heresies, they have an uncanny ability to layer the music -- separating everything out from top to bottom. In other words, I think they do a better job of pulling low level detail out of the music and getting it to the ears. Then of course there is the slam factor. The RF-7's are simply the bomb. They are an extremely 'fast' sounding speaker, and everything is very tight and buttoned up. I think Al K. is correct when he talks about the ears making adjustments. If I listen to the Heresies for a few days, and then go upstairs and fire up the RF-7's, I think to myself - "man, there's something missing here." After a few cuts off of a CD I say, "damn, there it is -- oh so sweet". The next day I'm in the basement on the computer, or doing some work in the workroom and fire the Heresies up, I say, "Yeah, they are a little bright -- not much warmth, and they could use a bit of polish -- a little more refinement." 1/2 an hour later I come out of the workroom -- and Kerry Livgren sounds like he's standing in my basement, and the cymbals sound like they're coming off a real drumkit. Heritage and Reference are simply two sides of the same coin. Debate is fruitless. They both sound great in different ways. That's all there is to it.

rotflol:) classic fini beautiful

Hee hee. I was actually thinking that TUBES LOVE HORNS:) Colin, did you ever try anything to alleviate the symptoms of the 8Khz hump (when you had your Cornwalls)? 100Hz bump sounds pretty good to me:) Anyone have an impedance curve for the Cornwalls? I'm wondering what the impedance is at 8Khz. Depending on the impedance at that point -- a tube amp may either exasberate, or smooth out that spot.

We really need our own FAQ link here on 2-channel. Especially guidance type stuff for new folks. I think Boa should head one up over in the HT section. I like the 'odds and mods' section, as well as the 'updating older speakers' section. The trouble is, if I have a question or problem, I come here, because 'here' is where I 'know' people. I usually just 'lurk' at the other places, and sure don't post often. Sometimes I need the hardcore unadulterated truth with no B.S. -- then I got hunt down John Warren, James McCall, or Tom Brennan. No offence intended to others here -- but if you've ever read their posts, you know what I mean. Sometimes I just need a reality check.

Thanks Andy! Even looks like something I can't screw up. Perfect. I wish you would change that signature of yours. I'm sure many here would agree that you are one of the more gifted and intelligent people that hang out here.

Sorry guys (Kevin also), the amp was just sold to 'Harry' -- a faithful lurker here at the Form (I think we would be surprised to find how many folks just love to hang out here and read about our lunacies. Art, The metal job on the Scott was done using a Scotchbrite scratchpad (equivelant to .000 steel wool, but does not fray), and 1500 grit cloth. Start with the scratchpad to loose all surface grit, grease, stains, etc. It's important to only go in one direction as much as possible. When finished, vacuum. Vacuum well, especially the tube sockets. Then begin again with the cloth. One direction only. It's not always possible to do this because of things you have to get to with wierd angles. Keep in mind that the cloth is removing a bit of metal, and so leaves a 'grain'. Going in one direction helps it to make it not to look like, well -- like some idiot scoured it with an SOS pad:) The whole surface will turn black from this process. When finished, used windex to clean everything off (spray the windex on a clean cotton rag, not on the amp). A tee-shirt will do nicely for this. At this point, go back over it again with the scratchpad to restore the satin look it started with. Again, one direction only. When you are happy with the look, vacuum again -- pay special attention to the tube sockets. Remove the bottom plate of the amp and vacuum. I used the horsehair brush attachment. When done, remove the brush and do the tube sockets from underneath. The whole process took me about 5 hours. Craig, The 299b will probably show up on your doorstep sometime next week. It's coming directly to you from Cleveland. I may want to drop some PIO's in for the coupling caps -- I'm still thinking. Kelly, Before I box this amp up, I will take several pictures of the bottom for you.

You actually think theirs someone here on two channel that actually doesn't know what the front of one of these looks like? Hmmm. Gee, guess I need to throw some up.

What the hell's wrong with you goons. I figured this thing would be gone in two hours. C'mon now. Fully restored and tweaked by Craig. This was Craig's personal amp, so you know he went the extra mile with it. Then I got a hold of it and put the sweat equity into the cosmetics. I may have to list this on AudiogoN soon -- if you are considering push-pull tubes, don't let it slip away.

Merry Christmas Aristidis! I had to put on sunglasses to look at the picture:) My KR300BXLS' are the complete antithesis of those Svetlanas. No light at all.