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Jubilee - Style Cabinets for Sale in Connecticut - EPILOGUE


PrestonTom
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First things first. I have carefully chosen my words. These are not entirely factory made Jubilees. 
That is why I call them ”Jubilee-style”. 

 

Bass Bins: They are made according to the details from the Journal of the Audio Engineering Society article by Delgado and Klipsch (2000) and further confirmed by others with hands on knowledge and inside information. The geometry of the back volume, throat, expansion, corners, reflectors, mouth and baffle are correct and identical to the factory versions. However, I made these as two half-height bass bins that can be stacked on top of one another. I’ll talk about the advantages of this later on. The frequency response and  impedance measures are the same as the published values. The drivers (K-31s) are the same ones used in the factory version. I have them currently stacked (as shown in the photos) as Woofer-Tweeter-Woofer. This has a number of benefits that I will discuss later.

 

Tweeter: The Tweeter horn is the Klipsch K-402 and purchased from Klipsch. Although the stock Klipsch K-69 is a good sounding driver, I upgraded to a JBL 2445 driver. It is also a 2 inch throated driver with a higher extension and a bigger & stronger magnet (For those interested, a JBL 2445 or 2446 can be purchased new with a street price of around $800). Since the drivers were upgraded, the DSP settings on the crossover were correspondingly adjusted after measurements were made and verified. 

 

Okay, that is now taken care of and there is no reason for anyone to corrupt a Garage Sale Post by arguing whether these should be called Jubilees or not. 

 

In this initial post, I will list the specifics for the sale. After that I will discuss some things that I learned along the way that I found interesting and that others might find useful. Since they pertain to this classified ad, I will do this as part of this current thread. If folks want to discuss these issues further, that would be great – but NOT in a Garage Sale Forum. Further discussion would need to be initiated in separate threads elsewhere (probably in the Technical / Modifications Section). 
 
Nuts and bolts: The Jubilees come with the components listed above. They will also include the cosmetics shown in the photos. If the grille cloth is not to your liking, then a trip to the fabric store can solve that. A staple gun will be your friend. 

 

Location: These are at my house in Preston Connecticut (06365). I am in the Southeast corner of Connecticut (near Foxwoods Casino & the Submarine Base). This is just off I95 or I395 and about an hour from Hartford CT, New Haven CT, Providence RI, about 2 hours from NYC, or Boston. They are currently hooked up so they can be auditioned (source is a CD Player). I am mostly retired, so scheduling should not be a problem.

 

Price: I am asking $3,300. For the pair. However, If the transaction is quick and simple, then I am willing to knock off 5% to 10%. For those of you who have sold used cars on CraigsList you understand what I mean. Those transactions are usually something that are not quick and simple – I am looking for the opposite. 

 

If someone is interested and wants a plug and play setup, I can toss in a DSP Crossover (Berhinger DCX 2496 either new for $250 or used for $150). I will also include a so called “passive preamp” (6 channel potentiometer in a metal box). The Behringer is nice in that it has plenty of processing power and can accommodate a digital input (AES/EBU or a S/PDIF). I am a believer in using a digital input and having the “passive preamp” after the DSP (since it will knock down any hiss or noise from a processor as the signal is attenuated). In either case, the buyer will receive the settings required for the DSP (mine or theirs). You will not leave here without knowing what to do. 

 

The Jubilees will require an active (DSP) crossover and four channels of amplification. Price-wise, on the lower end are Behringer and some of the dBx, Ashley, miniDSP units, moving up to Electrovoice and Xilica and further up to Yamaha, DEQX, BSS etc. There is quite a spread in price. My hint is that if you can get one with a digital input and place a multi-channel pre-amp after the processor, then it should sound pretty good (even with the less expensive units). The audition will be done using a Marantz CD player, Behringer DCX 2496 (DSP crossover), "passive preamp", a pair of Adcom 535 amplifiers. If you let me know the dimensions of your set up  (distance between the speakers, and distance of the chair to the speakers), then I can compute the "listening angle" and re-create that in my living room. You can then preview the same stereophonic spread during the audition.

 

The factory two-way Jubilees were being sold for roughly $8.5 k (raw cabinets, no grilles or veneer, and no crossover). That price usually included shipping but whether sales tax would be added was ambiguous (my guess is that one can seldom avoid taxes ….). The current two-way Jubilees (raw cabinets no veneer or grille cloth) were still being sold in early Spring, but it is rumored they are no longer available (probably not relevant to this Garage Sale thread so let’s not digress). I only bring this up as a point of reference. 

 

If you are seriously interested, please PM with an offer. Let me note what an offer should consist of. First – When and how you are going to AUDITION them. Second – When and how you will PURCHASE them. Third – When and how you are going to TRANSPORT them from my place to your place. 

 

Please think about the details on your offer. It will help me decide on whether the transaction is “quick and simple” and worthy of a discount. If you can assure me that they will be loved and cherished in a good home, there may be room for negotiation.

 

Let me tackle the usual questions before you PM your offer.
NO trades
NO, I will not deliver them
NO checks of any sort nor paypal. This is cash only
NO, I will not part them out


These are on a first come first served basis. Whoever pays for them first, owns them (again think of the idiots you meet on CraigsList who promise to have the money "next month")

The cabinets are modular and can be easily carried by two people. They would probably fit in a cargo van (remember the grilles are big) or a box truck (perhaps folks on CraigsList doing side gigs). A SUV would be tricky but I moved them in two trips using a Honda Odyssey.

 

Let's have a look .....
 

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IMG_0757.thumb.JPG.56e76f60b8d2f76995e2bd2e18b5f09f.JPG

 

What does not come through in the photo, is that the grille cloth has a linen texture to it, so it does not simply look like a sheet. The fabric of course can be swapped out. Get something thin and stretchy. Mine is a synthetic fabric. It only affects frequency response in the top octaves (about -0.7 dB at 8 kHz and is easily equalized). What is also hard to see is that the grille has a gentle curve to it, so it is visually interesting. I chose a color that made the big beast seem to disappear into the wall. The net impact is that when folks walk into the room, it will take them about 10 seconds before they exclaim "Hey, there are huge speakers in here" . Wait, did I say 10 seconds? How about 5 seconds, but you get the idea. With a "regular unadorned Jubilee" there is no hesitation. Incidentally, the exposed wood is a maple with a width of about 2 1/4 inch and has a tung oil finish. 

 

Believe me, they can be incorporated into your living room. They don't need to be hidden away in the basement. At one point in time (probably after a glass of some refreshment), I toyed with idea of a grille cloth made from a leopard skin print. Perhaps it was just reminiscent of the panties those women I was dating used to wear back when I was in my twenties. 

 

Anyway, the choices are endless.

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Photo 4post-15497-0-85940000-1449171483_thumb.jpg.17c92da4a23c508a1b83b4337a146ec6.jpg

 

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They can be tucked even tighter into the corners (these are toed-out a bit). Only a cat or a spider will see that the sides are not integral cabinets, but rather facades (they attach with 4 bolts in the handles going into hurricane nuts embedded in the "tweeter cabinets". Likewise, the bass bins are also bolted to the "tweeter cabinet" (both top and bottom). So the beast slides around on the base as a "single unit". The base has carpet pad underneath so it easily slides on a wood or tile floor (great for fine tuning the placement and toe-in).
 

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IMG_0783.thumb.JPG.6db19603106d0fcd483013e1ec66fd16.JPG

 

This gives a better idea of the tweeter cabinet (minus the K-402 horn of course). It is carrying a bit weight, so I braced it with hardwood boards. There is a lip on it where the "rib" on the grille can rest. I had intended to augment it with a strip of velcro but found it was not necessary. For those scrutinizing the details, it would seem that the final couple of inches on the bass-horn-path has some discontinuities. It does not. I got worried that any discontinuity might cause some whistling (Iwas over-thinking things). So the edges/sides of the grill where it attaches to the "face" has a small structure to "meet" the end of the bass bin-horn-path (with a strip of foam at the actual junction). All that was done so I could sleep well at night. My words are not very communicative, so the photos later on might help.

 

I should also mention that the access hatch for the top bin is at the bottom of the bin and the access hatch for the lower bass bin is at the top (the shape looks like a "home plate". So the top (outside) tweeter cabinet has a 3/4 inch plate attached to it and surrounded by neoprene. The bottom (outside) of the tweeter cabinet has a similar plate surrounded by neoprene. Visualize this ..... when the cabinets (modules) are stacked, the plates fit into the access hatches. The neoprene serves as a airtight gasket. Since that modules have sufficient weight, there is no need for screws to tighten.

 

Yes, the modules are bolted together, but that is so they can be dragged as an assembly. They really are not required for snugging the plate to the access hatch. Sorry no photos, but I hope you get the idea.

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IMG_0777.thumb.JPG.d78a88216a21804f9ad61881af2cf416.JPG

 

Not a very interesting photo, but this what the back looks like. Since theses are in, or near, corners no one will ever see this angle. Perhaps a cat might sneak behind and get a glimpse. Or, if it will help you sleep at night, then a birch panel from the stock they sell at the big box Home Center, can be cut up and bolted to the rear/sides of the "tweeter box". Wipe it down with Tung Oil and you will have a perfect match. Really ..... why bother. The cat won't let out your secret. If it does ... well, I have an excellent recipe for BBQ with a cumin, onion, garlic, and turmeric sauce. A bit of chutney relish as a topping .... your guests will be happy. If your guests ask "what was that stew you made", pretend you don't speak English. Sometimes, this will work. 

 

What is pictured is the big JBL 2445 driver. It is basically a beast with a 30 lb magnet. Of the different drivers I tried, it measured and sounded the best. 

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These two photos show the side and "inside" of the grilles. With a screwdriver and staple gun you can swap out the grill cloth material. Perhaps paisley, or a leopard skin print, or an air brush of a Native American Brave on his horse with a buxom and beautiful princess. Nah, stick with what I have done since sometimes you don't want a "conversation starter". Remember, you are not living in your Mom's basement with 17 cats. You are the sophisticated guy who is a hit with the ladies. 

 

Seriously, In the lower photo (which matches with with the lower half-height bass bin). there is a structure on the side which "completes" the bass-bin-horn-path. 

 

The second thing to notice is the luan panel that meets the bass bin "baffle". There is coarse black cloth stapled to the luan. On the other side (facing the room) and under the coarse cloth are a few inches of Rockwool/pressed fiberglass (not the fluffy stuff). This has a couple of benefits that I will detail later. Of course, this is replicated on the top third of the grille also (for the top bass bin). I suppose that I could have glued the Rockwool directly to the baffle and not incorporated into the grille itself, but I thought it was cleaner this way. Later, I will explain the benefits of absorption on the baffle. 

 

Unless you are trying to show the baffle on conventional Jubilees (where the veneered panel might be), you may want to consider doing this. 

 

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Modification: Why the split cabinet configuration

 

A few reasons.

 

1) The factory configuration (both woofers in a single cabinet) is a heavy cabinet. Your brother in law (and your lower back) will thank you for this modification. The 'cabinet" is comprised of three modules (one tweeter cabinet and two half-height bass bins). The three modules are bolted together. 

 

2) splitting the cabinet in two allows for extra bracing (although later version of the factory cabinets do have additional bracing). If you have an early version, you can always add a brace to the final flare (it does not need to be massive, just well-attached).

 

3) If you want, you can configure them as Tweeter-Woofer-Woofer. This is essentially what the factory version does. When mine are stacked this way, the frequency response and impedance sweep are the same as the factory version. In this configuration, the tweeter is well above the listener's ears. Whether this is a problem will be a personal preference. It also puts the Tweeter closer to the ceiling and the ceiling reflection is more objectionable. Again this will depend on the geometry of your room and how close you are sitting etc. I found that in a room with a 7.5. or 8 ft ceiling, the ceiling reflection gave an audible change in timbre. The effect was not night-and-day, but it was noticeable. Enough so that I changed the configuration (from T-W-W to W-T-W) and lessened the ceiling reflection.

 

4) Or you can configure them as a Woofer-Tweeter-Woofer (W-T-W). This is what I ended up preferring and doing. First thing I noticed was that the timbre seemed more accurate  or natural. I attributed this due to the diminished ceiling bounce. Although the center of the tweeter is also now aimed at the height of the listener's ear. The other effect was that (for lack of a better word) the sound seemed more "coherent". Interestingly when I looked at the frequency response (amplitude) from about 300 Hz on up there was no difference (between W-T-W and T-W-W). However the phase response (W-T-W) seemed "better behaved" in the octave surrounding the crossover region. I will stop there since trying to equate audible changes with physical changes in the phase spectrum is tricky at best.

 

I will say there is a weird side benefit in the W-T-W configuration. You can actually sit fairly close to the cabinet(s) and still have an "integrated" sound (again, for lack of a better word). I assume this can be understood by "adding up the vectors. With a bit of hand waving - the bass essentially comes from four mini horns (two half-height horns vertically spaced about the tweeter's center and each of these bifurcated horizontally about the tweeter's center. That is a tongue-twister so try and visualize the "center of where the bass is coming from - both the tweeter and the bass have the "same center"). Maybe this why the sound is integrated even at fairly close distances. Note, even "regular Jubilees" still have decent integration at somewhat close distances. 

 

The other thing I noticed, and it was especially true in the smaller room (7.5 ft ceiling), was that the bass was more even and less mushy. The frequency sweeps showed shallower peaks and nulls (in the W-T-W configuration). It is probably not the cure all for all room effects/interactions/problems, but it certainly helped. However, I doubt that it would make much of a difference at the lowest octaves. 

 

Importantly, this idea of a W-T-W vs a T-W-W configuration is not novel idea. It has been around for decades. It is usually done so the energy (lobe)  near the crossover region can be aimed at the listener. The driver-driver distances are usually much smaller and the spectral regions are usually much higher. I don't mean to sound like I think I invented something new (I am not that much of an ego-maniac). Some of the effects that I "discovered" in this case are interesting and not usually discussed. Discussing these in a separate thread might be of interest (but not this thread please).

 

All in all, I like the ability to stack the half-height bass bins. 

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Modification: Why the absorption on the "baffle"

 

 

This has a bit of a background story on it. When I first built my Jubilee bass bins, I wanted to use a smaller tweeter horn. The big K-402 seemed large and it was too expensive and was not always easily obtained. I did not see how I could make it work in my space due to its size. I decided to try the little brother, the K-510 horn (a nice horn by the way). Rather than crossing it at 500 Hz, I wanted to cross it about an octave higher. The bass bin can go that high. Unfortunately, if you cross the bass bin above about 700-800 Hz, the bin's dispersion becomes problematic. The rule of thumb is that the two drivers (tweeter horn and bass bin) should approximately match, in terms of dispersion, around the crossover region. What I mean by dispersion is the angle off-axis where the top and/or bottom roll off about -6dB (broad beam of sound vs a narrow beam of sound). With a bifurcated horn (eg Belle, Klipschorn, or Jubilee), the sound will roll off (more so at higher frequencies) as you move off-axis. This is standard. However with a bifurcated horn it may not continue to roll off as a function of angle. The response may actually rise again and on a polar plot it will appear as a "petal". There is a discussion of this in the Delgado and Klipsch JAES (2000) paper. There it is couched under the label "splay angle".

 

Is there a way to decrease this "petalling"? Yes, a few inches of acoustic foam on the baffle (in between the two bifurcated sections). When I say foam, I mean a few inches of pressed fiber glass, acoustic foam or Rockwool (which is what I use). I do NOT mean closed cell foam, fluffy fiberglas, felt,  or egg crate. You need to get the right stuff and 1/2 inch layer will do nothing. Someday this might be a useful trick for some of you. Why the petaling occurs to begin with can be part of a separate thread.

 

Well. later on I was able to get a K-402 horn, but I had learned something valuable with above exercise.

 

First, there is an inherent an problem with bass horns. We live in a practical world with living rooms that are a practical size. Horns are effectively an impedance transformer. To make this transform, the wave's impedance must be comparable to the impedance at the throat (small cross-sectional area) and again at the mouth (large cross-sectional area) all this as the expansion grows by a certain function (exponential, conical etc). If the horn is too short or the mouth too small, then the transformation is incomplete and not all the energy is launched into the room, part of it is reflected back to the throat where it may combine with the next wave either in phase or out of phase. One solution is to make the horn as large as your garage - I guess that is not practical. Incidentally, Roy Delgado sometimes refers to this waveform traveling the length of the horn as a bubble that is being stretched. 

 

In a Jubilee the response shows peaks and dips due to the problem outlined above. There are peaks at around 100, 180, and 300Hz and dips around 75, 210, 260, or 340 Hz. The peak-to-trough ratio at around 200Hz is especially severe (around 9dB - the measured severity can depend on the space the cabinet measured in ie, floor, wall, pair of walls etc). 

 

What tricks can be used to decrease this peak-to-trough ratio. There are several.

 

a) the closer the Jubilee is to a boundary or boundaries the better. So place the Jubilee near a corner (it will also boost the overall low bass and works with all cabinets in fact). 

 

b) DSP, Roy's DSP setting are not just for the crossover. Along with balancing the relative gains, compensating for differences in driver delays, the settings provide high end boost (required for all Controlled Dispersion horns), and they knock down some of the peaks (discussed above). So the amplitude response will then have less pronounced peaks and troughs. 

 

c) The last trick is what I stumbled upon. Place a few inches of acoustic foam or pressed fiberglas or Rockwool on the baffle. This will further diminish the peak-trough ratio. I discovered this for myself when I was worried about dispersion with a bifurcated horn (hence the "story" at the beginning). It always pays to do before-and-after measures. 

 

Now, do I think that I am the only one that knows about acoustic foam on the baffle of a bifurcated horn? Of course not!

However at the time it was news to me. Maybe this will help others also.

 

 

 

 

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In reviewing what I wrote I see a couple of problems in the background. 

 

First, I spent a good deal of time showing the cosmetics. I understand that this approach or strategy is not for everyone. It is meant as an example of what one could do to "make Jubilees work in their home", and perhaps save their marriage. If it gets you off the fence and gets you to decide "yes, let's make this happen". Then by all means go for it. 

 

Second, I have listed a couple of modifications and hints that might help others. I think they are worth trying. While I feel the improvements are worthwhile, I do not think they are profound nor do I think they are necessarily new. First, all of us fool ourselves and think our ideas are profound ( I am no exception). Secondly, Since I am ignorant, the ideas are, in fact, new to me. 

 

However the real credit goes to these two guys. I hope that nothing I have said is seen as undercutting their very good work.

 

 

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Enough about hints and modifications. This is a Garage Sale thread so let's get back to the classified ad (please remember to be respectful and do not pollute a Garage Sale thread with off-topic stuff - you can always start your own thread in the Technical / Modifications  section)

 

 

So Gentlemen, you have a choice in life. You can either enjoy the finer things in life like my friend here and get some Jubilees. 1065181159_coolguy.jpeg.3ebea49e567b4f1dda70e98117efcaa9.jpeg

 

Notice that he is suave, debonair and the man about town (and a hit with the ladies)

 

Or you can fail to get Jubilees and end up like this fellow - living in his Mother's basement and taking care of her 17 cats

 

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The choice is yours

 

 

EDIT: upon further research, I conducted a seance last night (induced by the Pinot Noir that the Women's Volleyball Team from UCONN had gifted me). During that ceremony we channelled the spirit of Paul Klipsch. His spirit, from the beyond, told us 

 

 

 

PaulSpeaks.jpeg

 

 

 

It really was remarkable, but it did not stop there. His next words were direct and profound. 

He said:   "I think      insert your name here      must buy Tom's Jubilee speakers"

 

 

Forgive the irreverence, but selling Jubilees is never an easy thing to do. I will be moving and homes by the water (my dream) are small and the extra money for extra square footage would be outrageous.  

 

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  • PrestonTom changed the title to Jubilee - Style Cabinets for Sale in Connecticut - EPILOGUE

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