DizRotus
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Posts posted by DizRotus
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This is a very interesting and educational thread. Especially to someone who is contemplating a DIY OTL to drive DIY Khorn derivatives with DIY versions of ALK Universals. The nominal impedance of Khorn or La Scala might present a problem to an OTL.<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />
The measured impedance on the La Scalas I just worked on was 3.7 Ohm. My sons Heresies show 7.6 ohm. Are those impedances correct? As I recall, my old Speakerlab Skhorns were the optional 8 ohm versions (standard was 4 ohm) but I ran two pair in parallel to produce a 4 ohm load. I never actually measured the impedance.
While I had the DMM out, I measured the impedance of my Radio Shack 40-1197 single drivers in Fostex FE-103 designed rear horn enclosures. They measure 7.6 ohm without the notch filter (10 ohm resistor in parallel with 2.2 uF) and 17.6 ohm with the notch filter. The filter, obviously, lowers the efficiency, but tightens the bass and smoothes the midrange.
Its slightly OT, but Id welcome a tutorial on why notch filters, including the famous, or infamous P-Trap) work.
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The installation of the Speakon connectors was straightforward. They are much better than 1/4" plugs & jacks.
The only surprise was the fact that the wire connection points on the panel mount side are 3/16" spades (without holes large enough to pass a wire) that are close together and at right angles to each other. Their small size and positioning makes soldering impractical and inelegant.
The solution is to use 3/16" female terminals capable of accomodating 14 ga wire. It then becomes imperative to protect the connection points from impact and/or accidental disconnection. Neither is much of a concern inside a speaker; both are concerns inside an instrument locker. I mounted electrical "knock-out" boxes over the openings in the 3/4" MDF locker walls in which the connecters were attached.
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On another note, any La Scala, <?xml:namespace prefix = st1 ns = "urn:schemas-microsoft-com:office:smarttags" />Cornwall and/or Klipschorn enclosures (no drivers, horns, etc.), in ANY condition, would be of interest to me. I'll store them in our warehouse next to the vault.<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />
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And now for a peek inside.
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Don't forget that the vault is available to forum members to safely ship pristine Cornwalls. If interested, contact me by PM or email for the details. Then I'll direct you to Gilbert who will fill in the details (if he's not watching an F1 parade . . . I mean race).
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Trey,
Thanks for the endorsement. I guess you can't beat Liechtenstein when it comes to quick connects.
The attached photo shows the cable end connector on the left and the panel mounted receptacles on the right. The upper set is exploded and the lower set is connected. You can see the small set screws in the upper left just behind the grey collar. They look to be very well engineered and manufactured. They should be a vast imporvement over 1/4" plugs and jacks.
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The following, in blue is, from a previous post (False corners screwed into K horns?http://forums.klipsch.com/forums/thread/401946.aspx):
Permanently attached false corners worked for me.
I know this is heretical, but in the mid 70s I used four Speakerlab SK-Horns powered by a Dynaco ST-400 for a mobile DJ business. Knowing the speakers would be moved often and that real corners would not always be availableread NEVERI used the plywood shipping crates to make false corners attached to each speaker.
I never measured the difference in bass response between placements in real corners and freestanding with the false corners, but there appeared to be no difference. In either configuration the bass was prodigious and tight. One customer who called to schedule a return engagement asked if the price quoted included the drummer. It was all I could do to convince her that there had not been a drummer at the earlier engagement.<?XML:NAMESPACE PREFIX = O />
The one time I met PWK he was surprisingly diplomatic about my confessed use of the Speakerlab copies. He allowed that it was better to subject the impostors, rather than real Khorns, to the abuse of 600 watts of SS power, junior high students and frequent assaults by hand-truck.
Actually, they were perfect for the task. Unloading four black plywood obelisks never failed to impressneither did the sound. Invariably, as the first speaker was unloaded, someone would ask, Is that the speaker? to which I would reply, Yes. There are three more.
The size made it impossible for someone to walk off with one of the speakers when my back was turned. I did have to put hardware cloth (wire mesh) over the mouths of the squawker horns and over the backs, to prevent mischief. Once a napkin had been stuffed into a squawker horn and another time a kid unscrewed an Atlas squawker driver. I got it back after the principal of the school announced that there would be no more dances until it was returned.
If I ever supplement my Cornwalls and Hereseys with Khorns, I will again go the affixed false corner route.
Another thread that dealt with the topic is: Who made the Drivers for the Speakerlab K's, http://forums.klipsch.com/forums/thread/533168.aspx
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That's better yet. You might put a rubber grommet where the cable goes through the metal locker. Let me know how easy those Speakons are to install, I've used them but never been inside one.
M
Only the locker doors are metal "cages;" the tops, backs and sides are 3/4" MDF.
Your friend DrWho speaks highly of Speakon®, I'll let you know what I think in a few weeks.
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The cables are attached to the tops of the lockers from the speakers to the ends of the lockers. Next, they go down through holes in the tops of the lockers. Finally, they are attached to the insides of the end lockers. The jacks are at the bases of the lockers. When the plugs are removed, there are no loose wires.
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MONO RULES
Allan,
I was waiting for you to stand up for mono.
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Im interested in geographically reasonable La Scala and/or <?xml:namespace prefix = st1 ns = "urn:schemas-microsoft-com:office:smarttags" />Cornwall enclosures without networks, drivers or horns. They can be in any condition. I would pick them up, so shipping is not an issue. Theres no hurry.
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Michael,<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />
I appreciate your concern, but please recall that I am a recovering attorney (I was a litigation attorney for more than two decades). While it's wise to avoid unreasonable risks, in our litigious society, it's impossible to live your life in a way guaranteed to make you litigation proof. In this great country, anyone can sue anyone over anything; just ask MJ.[1] All they risk is the cost of filing the litigation. The only guaranteed winners are the lawyers. Perhaps the Bard was right.
All reasonable precautions have already been taken. When the cart with the receiver and CD player is in use, the director needs it centered (left to right) in the front of the classroom. The power cord and speaker cables go back toward the wall. Students are not permitted to go into that area. The hazardto the students and the cableswould be if the cables were disconnected at the cartrather than at the lockersand left lying on the floor when the cart is locked away in the office.
The only way to avoid the power cord and/or the cables from temporarily traversing the distance between the cart and the front wall would be to run wiring under the floor or drop it down from the ceiling; both unreasonable IMO. Neither would make the school invulnerable from suit. Someone could trip, slip, fall, etc. over the unexpected floor mounted connector or someone could get TMJ, a closed head injury or cervical spine injures from colliding with the wiring hanging from the ceiling or from looking up to the ceiling to see where the wiring goes.
FYI I ordered the Speakon® connectors.
EDIT: @11:17 EDT
While you were editing your post, I was composing the above. As you can see, what you describe in your edit is essentially the scenario.
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. . . from the library, at least. Its not meant to start a flame war.<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />
One can actually check out CDs from the library and listen to the music. Did you ever try to check out a record? If you werent the first person to get to it, you might as well drop the stylus on the turntable's mat. At best, you might be able to hear enough music through the dirt and scratches to decide to buy a clean copy.
With CDs you can actually hear the music. As I type Im listening to disc 3 of Miles Davis Chronicle the Complete Prestige Recordings, from the public library, they sound great even though Im not dragging a semi-precious gem across vinyl.
Personally the vinyl horse left the barn and took my TT (modified AR/SME/SHURE V-15 III) with it, and I don't miss the hassle, but Ill defend anyones right to prefer good vinyl to CDs.
Not that I mind, mind you, but this thread has gotten--predictably--way off topic.
Listenable CDs are available at most public libraries; LPs are not, and never were.
When LPs were still generally available at libraries, their poor condition made them virtually useless. Today, even abused CDs from the library can give you a taste of the performer, the performance, the recording, etc., if you like it, you can buy it in whatever medium you prefer, in which it's available.
You may now return to debating the relative merits of analog and digital.
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Bruce & Michael-<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />
Since the cost difference is insignificant, the Speakon® hardware seems the better way to go. When you say theyre "lockable," does that mean that they always "lock" into place? These get connected and disconnected daily. A locking feature might be a nuisance and/or quickly broken.
The band director does not want cables loose on the floor when the speakers are not in use, i.e., left and right cables unplug from the bases of the respective locker and get coiled up and stored with the cart. That way, no wires are left on the floor to get damaged or trip someone.
Regarding portability of the speakers, they are not coming down from the lockers in the foreseeable future; they were never intended for outdoor use.
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Please go to Neutrik® or Speakon®?
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Which quick connect to use with schools La Scalas?[1] Right now we are using ¼ plugs[2] so that the director can quickly disconnect the speakers (which stay in place on top of the instrument lockers) from a cart that holds the receiver and CD player. The cart is then locked in his office.<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />
While passing time in the library reading the 2006 Parts Express catalog, I was checking out the connectors on pages 72 and 73. Either the Neutrik® or Speakon® appear to be better solutions to the quick connect/disconnect need than the ¼ plugs, which tend to make poor connections over time, requiring constant attention.
I have no personal experience with either. Which would be better, or is there another comparably priced solution somewhere else in the PE Catalog? What are the advantages or disadvantages to each? Its just to conductor, but we want to guarantee correct polarity and it would be nice if we could make it so that the right cable would only mate with the right receptacle and left with left.
After returning the PE catalog to the rack, flushing and washing my hands, I exited the library to post this thread.
[2] Parts Express #092-202 and #092-122
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Routers johnson rod exploded [li]
At least the forum doesn't appear to be totally instead you feel special by being the only person on the forum and afraid to leave just in case somthing goes terribly wrong if log out. [8-)][*-)][^o)][:@]
Just before the Johnson rods let go the chrome muffler bearings failed.
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The speakers are back on top of the lockers. Unlike the earlier photo that showed a speaker resting flat of the locker, they are now raised ~3" in the back, so that they fire down into the area where the band sits, rather than over their heads. They're also angled toward the center.
Recognizing that a large empty band practice room with speakers > 6' off the floor is not ideal, they still sound very good. The improved low frequency response is still apparent. So, far the band director is pleased with the changes. The six people who helped get them back on top of the lockers were very impressed with the sound.
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Michael,
Of course, you know that I'm not saying that these are better than Cornwalls, just similar in some ways and different in some ways, not better or worse.
I will say that these are better suited to their duty in the band room. Corwalls would be wasted in that environment.
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I have owned and love Cornwalls. That comment was not meant to disrespect Cornwalls, but whereas Cornwalls are often described as having "slam," these now have Cornwall-like bass, but with La Scala tightness. Don't forget that these have a 400hz squawker horn, where the Cornwalls have a 600hz squawker horn.
Without measuring equipment, it's impossible to quantify the reduction in efficiency. That said, with the stock Type AA network the modified speakers were too prominent in the mid-range. The switch from tap 4 to tap 3, combined with essentially halving the capacitor value, knocked the squawker down 3dB, which seems perfect. Naturally, it now takes more power to produce a given volume, but the low powered Dynaco and H/K 430 have no problems playing these way beyond a reasonable level. These appear to still be efficient enough to satisfy the SET crowd.
The success of this mod should not come as a surpise. Altec VOTs have used a front horn/reflex cabinet for decades.
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So far, I like Sputnik's dog catcher campaign car the best.
If you think the La Scalas are making the MX5 do a wheelie, you should see it when my mother-in-law rides in the trunk.
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After more listening, I'm even more impressed. I substituted a mildly modified Dynaco SCA-35 tube integrated amp for the H/K 430. The Dynaco has a nominal 17 WPC (probably actually more like 10 WPC) but sounded very good; better than the H/K 430, for the most part.<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />
It's a cliché, but I truly was hearing things while listening to Kind of Blue that I did not notice before, such as a bowed, rather than plucked, acoustic bass. Of course, I've not been listening to that recording regularly on these, or any other, La Scalas so I can't swear that the bowed bass would not have been apparent without the modification. Nevertheless, piano, percussion, acoustic bass, electric bass, vocals and even the heartbeat from Dark Side of the Moon sound very good from these speakers. They are like Cornwalls with more snap rather than slam.
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This photo shows the network in place. I used the two terminal barrier strip that formerly provided the connection to the woofer through the sealed dog house to now provide the input connections on the outside of the newly covered back of the top section.
The new caps arrived from Bob Crites yesterday and are now in place. Honestly, in the garage setting with the H/K 430, I can't say that I noticed any difference between the 15 ohm swamping resistor and the lowered capacitance. With the squawker (+) moved from tap 4 to tap 3, in either case the squawker was attenuated enough to now blend smoothly with the lower in frequency, albeit lower in efficiency, bass output.
Cuts with which I'm familar now sound better than ever from these speakers. The acoustic bass and percussion on Take Five from Time Out are still fast and tight but now have more power down low. The drum solo in Devil May Care from Diana Krall's Live In Paris is still fast and tight.
Obviously, there is no free lunch. The increased bass output comes at the expense of some efficiency. Nevertheless, these are still very efficient. The 25 WPC available from the H/K 430 drives these to levels that would have summoned the police very quickly.
I would encourage La Scala owners to try this fully reversible modification.
EDIT: 12/20/2015
Photos deleted to free up server space.
<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />
Cornwall Vault and Wanted empty BEATER enclosures
in 2-Channel Home Audio
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