Chris A

Sorry if a gave the wrong impression - I wouldn't be asking these questions if I weren't interested or considering. The real issue is that I don't see much in the way of a sub that is up to the task and is economically viable, including architectural real-estate costs. Very few folks here are seriously talking about buying a sub that extends the Jub lf less than an octave, and injects significant THD. I feel this is something that is contrary to the main attractiveness of the Jubilee itself - low THD.

Actually,What I was intending to say earlier was that a starting rule of thumb might be that the sub should extend the lf down at least one octave from the corner-loaded -3 or -6dB point of the Jub bin. I wasn't looking for a wide bandpass of the sub itself. I don't see the economic advantage of investing in a sub in that only extends the lf down a couple of notes before it is into its own lf cutoff region. Do the Klipsch subs (e.g., KPT-884) suffer from this problem? The issue is that to actually hear anything below about 25 Hz, it has to be very loud due to Fletcher-Munson effects. I think most people think that they are listening to low bass but really are listening to the second and/or third harmonic - and that is what I think is meant by "club sound". They might feel those frequencies, however. Addendum: Injecting second or third harmonic content into the bass line electronically is probably not difficult. I think that is the preferred way to get "club sound". In that way, the option exists to turn it off. I'd be interested in hearing about your DIY tapped horn project results. Is it already posted here somewhere? Chris

Mike (DrWho), You have a PM.

Exactly. Now all we need is horn-loaded subwoofer whose driver really doesn't move and plays sub-20Hz with ease. Any ideas--short of making the side of the house a horn? The TRW fan subwoofer moves, doesn't it? Chris

Roy, You have a PM. Chris

I believe that the subject turned to "if one was going to use a sub with a Jub, then what should we be paying attention to?" Roy mentioned that direct radiator subs usually have a lot of THD, and that paired with the Jub lf bin, it (the sub's THD) was very apparent. He then commented on what you might have to do to match the Jub's performance with a sub (or series of subs). I concur with his assessment. My comments were directed toward the difficulty in simultaneously attaining real lower bass performance (e.g., at least one octave below the Jub lf bin - ~16 Hz) and low THD required for Jub use. It really begs the question: "do we really need a sub with a Jub, because it degrades the overall performance?" which I still am waiting for someone to chime in on. I'm a patient guy kind of guy--I can wait until the stars align to ask that question again...

Of course, there is the Eminent Technology TRW "fan subwoofer", but it needs a large custom-built antechamber to kill the fan noise (and about $20K to acquire) to install. But it goes down to 2 Hz, and a single unit will do ya...

You know, I've read in several places that the Lowther-based full range horns don't sound that good--reading opinions written on this side of the Atlantic. I can see that with the horn above, the horn-loaded lf backwave in that design would have a fierce delay problem that cannot be corrected in that configuration. I also assume that IMD is big for that single driver trying to pump out mf without benefit of horn loading. I also assume that those designs really don't enjoy the kind of dynamic range of multi-driver horn-loaded systems, e.g. Jubilee, Khorn, Lascala, etc. It is evident that function doesn't follow form in acoustics and I think that the full-range driver idea doesn't work well in that light. If you try to correct for the not-enough-driver-area issue by using multiple full-range drivers that are identical in order to get more driver area, then, voila, guess what you get? And we all know about those type of speakers. (I won't speak that name in this forum.) As Nam P. Suh, formerly of MIT, and inventor of Axiomatic Design might say: "...the use of a single driver system will result in a multiply-coupled system design...", and that isn't good karma. Chris

Good plan...

Too late - he's signed up to show up tonight at my abode--I'll go easy on him so you can take credit for "turning him to the dark side". And I'll leave the planters to you--I need the room for other things... Chris

You know, I had the same thing happen at my place...except it was James Taylor...and my son wasn't dancing, just the wife. (Son is 21--so dancing is uncool.)

yep. horn mouth area vs radiating area of the woofer. the loading should be very similar for both; what i mean if you put the horn in a corner, then the sub should be in a corner as well. if not, you will have to compensate for the loading. now remember, i said you would begin to approach........ in Christ, because of God's grace, roy Let me see - four 18" woofers that can take the operating lf down at least an octave from the Jub lf cabinet in the corner position... By the way, is there a response/phase curve on the Jub lf bin while in a full corner? I would think we are talking about two subs that have strong, undiminished output to an octave below about 32 Hz, right? My calculation says--drum roll--16 Hz. What subs have two 18" woofers and undiminished output down to 16 Hz? Four Epik Conquests - mounted in the corners? Actually, as I recall, the Jub lf bin is a bit bigger in the mouth than the Lascala, isn't it?

Me too - seems like most of those weird speakers live in places other than where I live...

And a slightly newer model (but this one does need a little delay correction)...

I believe you quoted the price per pair, in matching black. And "huge" just doesn't quite say it, does it? (See pic, below.) Congrats travis! For your sake, I hope that you have an addictive-resistant personality. You'll need it, partner. Chris

Roy, Please check your email (your home address). Chris

Peace, brothers...I do not wish to appear to be anything but inquisitive. Many folks apparently believe that the 402 is a "straight tractrix" (i.e., one tractrix curve for each axis of the 402): I don't believe it is. I would like to know if the 402 design uses some sort of "rubber throat" or "reverse rubber throat" design and why. Why, for instance, is it "modified". Effective use of the English language is difficult enough as is. My apologies if I provoked any argument - that was not my aim. Chris

It would better than the Lascala, in terms of bottom end extension but not as good as the Jub lf bin in harmonic distortion. Roy published a freq response chart for both the Khorn and Jub bins some time ago (e.g., you might search to find on this forum). The Khorn lf bin isn't that bad, but it has higher THD throughout most of its range, probably due in no small part to its 90 degree folding (vertical, then horizontal), the single driver in the Khorn bin, and to worse internal discontinuities, rather than the two-180 bend/two-driver configuration in the Jub lf bin. I don't know a lot about the K-69-A, but it appears to be the same upper driver on the 3-way Cinema (i.e.., KPT 535 Jubilee) configuration, but using the K-510 horn as the final hf step in the 3-way configuration. The equalization curve for this driver in the K-402 is also published on this forum (Two-Channel, under "Re:Jubilee") as the hf EQ for the Crown XTi DSP/amp. Chris

No, it really isn't but I might understand your assumption if you didn't have one in your hands to measure. That flat area 2/3 of the way out to the mouth--Large Manufacturing Error? I believe that no one else has acknowledged its presence. I believe a math major wouldn't call the horn "tractrix". I believe that I'd call it "custom, something..." and it looks tractrix at the mouth. It also looks exponential or tractrix at the throat--either definition looks close enough to me. That flat area isn't either one. Maybe the resident Klipsch project engineer could shed some light? (Roy...your cue.) Addendum: I would guess what we have here are two tractrix expansions in the K-402 with some sort of tangent line connecting the two (i.e., the flat area), such that there exists a smoother transition. Why two expansions? I don't know---maybe something having to do with coverage vs. frequency is affected at lower frequencies, or maybe the horn just needed to be shorter to match the depth of the Jub bin and the starting expansion rate near the throat is milder in order to support higher freq coverage. Your guess is as good as mine. Chris

There is a large discontinuity (i.e., area of essentially zero curvature) in the K-402 shape about 2/3 the distance to the mouth, and there isn't a lot of difference that I can see between exponential and tractrix as you move toward the throat of the horn (see figure below). I assumed that it was a "stitched design". My error... I wonder which end of the horn shape is modified? "It will be seen that the tractrix has a dominant exponential term which becomes less significant towards the mouth; in fact for the first 50% of their length the exponential and tractrix contours for a given cut-off frequency and throat area are virtually identical, but thereafter the tractrix flares at an increasingly greater rate until it attains its fully developed mouth at 180 degrees included angle."

Thanks - I swiped it somewhere. It seemed to make the right statement.[8-|]Chris

The K-402 is the tractrix-looking horn on top. The K-69-A is the driver attached. The K-402 horn is a compound shape that clearly ends in a tractrix-shaped flare at the mouth (i.e., the horn's mouth rolls out tangential to the mounting surface unlike the exponential contour) while the interior of the horn looks to be exponential conical. The horn is crossed at 500 450 Hz to the lf bin that you recognize as the "Jubilee" bin.Chris

Michael,You're very welcome. I'll repeat my offer to those that want to hear these - just send a PM or email to set up a time to audition the Jubs. I'll supply the chips and soda--you supply the music. Admission: free. Chris A.

A couple of things:1) I believe Mr. Fourier. The "impact" you refer to translates for me to relative drive force/mass for the amplitude of the driver diaphram movement. Build-up response is what I think of when you say "impact". Horns typically have a less build-up response because the diaphram doesn't have to move as far. The horn itself is an antenna that matches the electrical impedance of the amplified music signal to the air's acoustic impedance, thus increasing efficiency of the transmission, and simultaeously decreasing the required amplitude movement of the driver. 2) I believe Messrs. Fletcher and Munson. I think a lot of people listen to second harmonic distortion in low bass (i.e., particularly below about 40 Hz) and think that they are listening to "deep bass". I believe they might feel the fundamental, but hear the second harmonic (unless it is unbelievably loud - above 110 dB). This is often perceived as "good bass" and is closer to what I mean by "THD of direct radiator bins". I don't think most people realize how pervasive second harmonic "deep bass" distortion is heard and accepted as "pure" bass. It isn't "pure" but it may be enjoyable to listen to particularly for certain types of music - unless you listen at 110+ dB levels all the time. I know I don't. In organ design--real organs, not electronic ones--many stops are intentionally doubled (i.e., are voiced with the octave rank above--in parallel octaves) because it is perceived as pleasant to the listener. This isn't bad, it's just not well understood that this is happening. My comment about the ServoDrive BassTech 7 and ContraBass units was meant to be an integral part of the discussion. This phenomenon is interesting vis-a-vis loudspeaker design. Chris

You asked a difficult question, i.e., "...what do they sound like when compared against the Khorns". I believe there are a couple of factors that will affect how different folks try to answer that question:1) Your tastes (e.g., look at the thread on the "JubScala" and jwcullison's comments about what he is looking for in lf performance), and 2) Your room acoustics, including where you listen relative to the speaker placement in the room. I own Khorn clones (reasonably good ones) that were in the corners of the room but were displaced when the Jubs hit the scene. For my room the Jubs' mf/hf performance was a dramatic improvement even though the Khorn is noted for its "live" presence. Understand, it's my ears and my room. The first thing everyone here noticed was the improved lf performance vis-a-vis Khorns. I had issues with both the Khorns and the Jubs in terms of standing room modes which I mitigated by using corner bass traps. These helped my listening room a great deal in terms of smoothness of soundstage vs. listening position. I strongly recommend such devices with your Khorns if you don't already have these in your present listening room, along with ceiling diffusers at the first bounce position relative to your sweet-spot listening position. You may be satisfied with your Khorns a while longer if you add these--"my opinion only". Note that bass traps really do not affect low bass below ~80 Hz - that is a function of the room's architectural dimensions and wall/furnishing absorption. My rectangular listening room is 15.5(w)x9(h)x39.5(l) feet. I listen about 10 feet back from the speakers in the corners. This may be responsible for many of my opinions. After I dialed in Roy's anechoic settings for the XTi's and Jubs, the mf/hf experience "came alive"--I don't know any other way I can express this. My wife showed up and bonded with the Jubs immediately after that (note: she has special constraints in hearing). This is essentially my "control" setup. I'm still enjoying that setup and have not varied it since before Christmas. I would also recommend using Crown XTi's at least initially (update: I don't recommend Crown XTi's for anything other than PA systems...get yourself an active crossover like an EV Dx38, DC-one, etc.) since they are not terribly expensive and they have the benefit of Roy's anechoic EQ/delay/crossover settings. It is difficult to know if you've duplicated this performance using another set of amplifiers and separate active crossover, e.g., an EV Dx-38. Note that the XTi's have quiescent noise which is not a function of amplifier gain setting that is apparent at the horn mouths when no signal is present. I have gotten used to this but others may not. Once any music starts, I cannot hear this. Corners: I haven't moved mine out of the corners since my room is tailor made for corner speakers. I would guess you'll take a 3-4 dB hit below about 50 Hz if you put them on a flat wall (update: You can use tapped horn subs or bass traps to fill the space behind and to the sides of the Jubs and the corners if you choose to move them out of the corners slightly in order to achieve a clear, uninterrupted space between the Jubs to improve imaging) - this is easily EQed out for most applications, and power isn't a problem since my XTi's are idling all the time, even when "hand volumes" are reached. I hope this helps your decision making. Chris