djk

I have seen that kind of damage before.It is not caused by a one time event.Repeated rear-wards over-excursion causes the starfish tears.Repeated front-wards over-excursion causes the cone to wear out at the point where the cloth edge stops.When the cone is new and stiff the coil keeps pushing on the cone after all the travel is gone and the cone gets soft where the dustcap is glued to the cone.One day after the cone has been softened up a large rear-wards excursion will rip the coil off the cone.Over-excursion causing starfish tears is usually a bad woofer inductor!!!Amplifiers with tiered power supplies (Carver, NAD2200,2400,2600) frequently rip the coil off the cone whereas amps with regular power supplies (Adcom 555,Hafler DH500,etc) do not have this problem.Soundcraftsman amps with the PCR power supply are absolutely the worst in this respect.

You have an interim Cornwall.The mid is from a Cornwall II and is either a K52 threaded onto a K600 or a one piece K57.

I've only seen one pair of Tangent and they used the Klipsch #127103 diaphragm.

Early 70's on the woofer, late 70's on the tweeter, and early 80's on the midrange.

Take out the diaphragm and examine the gap.Sometimes they pinch shut on one side from shipping.

Figure 9 in the JAES Vol. 48 No. 10 shows the Pi/2 anechoic response of a Klipschorn to have a narrow 5dB dip at 75hz and be flat at 50hz. I suspect your room is 14' X 22.5'

Check the tape monitor switch, then the speaker relay. It gets exotic after that.

Would you rather have a used Corvette or a new GEO? A used Bryston 3B could be found for around $500.I have a McIntosh MC2120 I got from eBay for $500.Hafler XL280 + DH110 for maybe $550.A NYAL Moscode 300 sounds incredible on Klipsch ~$600.Sumo 9+ ~$450.Electrocompaniet AW50 ~$450.Threshold S150 ~$650.Yamaha? I could live with a B2 + C2. Denon? A POA1500 is pretty but I could get an Accuphase P300 for $500.New or used?

A view of a JBL 475, a four port phase plug. This is a neodymium magnet version of the 375 which was a alnico magnet version of the WE 594 field coil driver. http://www.audioheritage.org/main/images/jbl/photos/products/drivers/475_xsection.jpg A three port phase plug. http://www.audioheritage.org/library/catalogs/altec/images/1971_monitor/page1.jpg A two port phase plug. http://www.audioheritage.org/library/catalogs/jbl/images/1976_Components/p-2.jpg A tangential phase plug. http://www.audioheritage.org/library/catalogs/altec/images/1978_mi/page02.jpg Note that the spacing on all the annular port phase plugs is essentially the same.The 4p is a 4" vc,the 3p is a 2.8" vc and the 2p is a 1.75" vc.

>>Which "frequency response errors"? How does the impedance of the speaker affect a tube amp different than say, an SS amp? << A solid state amp with feedback will have an output impedance of less than 0.1 ohms.A push pull pentode with feedback will be about 0.5 ohms.A push pull triode with feedback will be about 1.2 ohms.This figures out to .75dB for the pentode and 1.7dB for the triode compared to the solid state amp driving the impedance curve of a K/B/LS/C.A Heresy as a load would half the difference.A SET with no feedback will have huge errors.This is not entirely bad.The Klipschorn has a 108dB peak at 250hz that correlates with its minimum impedance.A SET with no feedback will deliver about 3dB less than a solid state amp at this frequency range.EQ where it is needed without buying an EQ? A SET with no feedback will vary about 6dB driving a K/B/LS/C compared to a solid state amp.Totally a function of the output impedance vs the load impedance.>> I have a Tandberg 150 watt solid state powering my Cornwalls and I love the sound. << I sold my Tandberg 3008 150W amp to a friend to drive the low end of his 'Super Cornwalls'.Dual K33 bottom with a modified Rane AC22 + B&K ST202 on the top.An ST120 or ST140 would have been enough but I couldn't find one used.The Tandberg sounded better than the B&K on top but the B&K sounded like mush on the bottom.

Just wanted to tweak your nose a bit.I built a pair of Cornwall sized speakers for my brother's church with an 8 X 10 slot in front of the K33 and and EV 8HD difraction horn front mounted vertically with the edge hanging over the front of the woofer frame.The K77 tweeter mounted horizontally above the 8HD.I also built six pair of 'Super Heresy' that had two K22 with the vertical 8HD + horizontal K77 set up.It does sounds best if all the drivers are in a line vertically.

This shot of an old Klipsch price list shows the old Cornwall II sideways with the long axis of the mid horn horizontal. http://members.aol.com/audiobabe300b/Ksheet2.JPG Here is the complete eBay auction. http://cgi.ebay.com/aw-cgi/eBayISAPI.dll?ViewItem&item=1229653832

This seems too much like work to me.I am going to try this one more time before I give up.Say you measure an amp with a 1Khz sine wave driving a load and you get 28.3V .Now you drive the load with a ten cycles of 1Khz (tone burst) once per second and get 40V .I am going to define this as dynamic headroom.In this case the dynamic headroom is 3dB.Amplifiers that have regulated supplies, choke input supplies (think tube amp), or huge unregulated supplies (think Krell,Roland,Levinson,etc) have no or very low headroom.The increase in actual power from duo-amping is limited to the dynamic headroom of the amplifier design.In other words it could be from nothing to say, 3dB.The worse the power supply regulation the higher the dynamic headroom will be.Removing the load current from part of the spectrum by duo-amping does not remove the voltage driving the input of the amplifier.Using an electronic crossover removes the voltage driving the amplifier above or below the crossover point.If you are doing a single sine wave analysis you will think these are equivalent.And they are for sine waves.But music has more than one frequency present at any given time.Assume a crossover of 500hz.Mix a 100hz 1V signal with a 1Khz 1V signal and parallel feed into two amplifiers with a voltage gain of ten.The signal coming out of each amplifier will be 20V.Now feed the same input signal into the electronic crossover and into two power amps with a voltage gain of ten.The amp driven by the high pass will have a 1Khz 10V output and the amp driven by the low pass will have a 100hz 10V output.Assume the amplifiers clip at 40V out.An increase in the input signal of more than 6dB will cause both of the parallel feed amplifiers to clip.The output signals from the amplifiers driven by the electronic crossovers will increase to 20V.Increase the input signal another 6dB.The parallel fed amplifiers will now be driven 6dB into clipping.The amplifiers fed by the electronic crossover will be just starting to clip.When I said >>Unless you are using an electronic crossover you are not increasing power in any meaningful way by adding two amps<< that is exactly what I meant.When I said >>The amp that sees no load in the bass will have a fraction of a dB more power reserve in the power supply assuming that the supply is not regulated(a reasonable assumption in mid-fi)<<that is exactly what I meant.I explained it the first time >>Even though there is no load as far as the current is concerned the amp still clips at the same point because the voltage is still there in the input signal.In a real bi-amp setup the electronic crossover removes the out of band input voltage so the amplifier does not have to amplify it<< and I gave you a clue here>>On a complex signal like music the voltages add<< and here>>You would be right if music consisted of single sine wave tones<<and I quoted Nelson Pass, someone most people would know and respect>>but keep in mind that the less powerful amplifier tends to set the upper limit on how loud you can play.I'm not a big fan of bi-amping in this manner. While it arguably offers some improvement, my experience is that the improvement is small compared to the additional cost. Both amps have to swing the entire range of voltage driving both the top and bottom ends. I greatly prefer an actual crossover before the amplifiers, so that the high and low amplifiers only have to contend with the signal in their specific frequency band<<who said basically the same thing I did and gave virtually the same explanation I did in response to virtually the same question elsewhere.You own an o- scope>>I have a scope, and a rack full of HP test gear<<.Hook it up to the speaker wired for uno-amp operation and run it up wih music until you see the amp start to clip.Mark that point on the volume control.Now unhook the low pass connection to the woofer.Now driving the high pass only run it up to the point where the amp starts to clip.Mark this point on the volume control.Unhook the amp and hook up a signal generator.With the volume control set to the second higher mark adjust the generator to get a 0dB output on a RMS voltmeter.Reduce the volume control to the first lower mark.The difference in dB is the increase in volume you get from duo-amping at the onset of clipping.

>>So, it is not hard to see the problem. Comparing two "nominal 100W amplifiers", 3.5A might be easily handled by two transistors, but 14A will certainly require 12 or so.<< Let's see....if one pair will handle 3.5A then two pair will handle 7A and four pair would handle 14A so four pair must equal 12? >>A power transformer will grow EXPONENTIALLY in size and weight as the power demand doubles. For 3.5 amps of current, the transformer might weigh 2 pounds, at 14A it could easily come out to 25 pounds of steel and copper! << A transformer rated at 4X the current is always less than 4X the weight.Efficency improves in transformers at higher power up to about 1KVA then levels out.From the spec sheets we see that a 320VA transformer is about 55VA/LB and a 1KVA ransformer is about 59VA/LB.Most 100W solid state amps would use about 38V X2 for the transformer rating.Run in amps per LB or VA the relationship is essentially LINEAR. http://www.toroid.com/solidamps.htm

The problem is crummy elecronics and bad recordings.Actually it is just crummy electronics because the bad recordings are made with crummy electronics.Virtually all top 40 program material and mass market electronics are going to suffer from this to a large degree.Good sounding recordings and electronics are often found under obscure names.

>>Nelson Pass 10+ Posts Posts: 13 From:Foresthill CA USA Registered: Mar 2001 posted 04-03-2001 02:41 PM Unless you have any level adjustment circuitry before each power amp, the easiest way to go is identical amps. If you can adjust the level of each amp, then you can get away with dissimilar amps, but keep in mind that the less powerful amplifier tends to set the upper limit on how loud you can play. I'm not a big fan of bi-amping in this manner. While it arguably offers some improvement, my experience is that the improvement is small compared to the additional cost. Both amps have to swing the entire range of voltage driving both the top and bottom ends. I greatly prefer an actual crossover before the amplifiers, so that the high and low amplifiers only have to contend with the signal in their specific frequency band. When you do this you not only get the benefit accorded to "bi-amping" but the amplifiers will operate with significantly less distortion, deliver significantly more power, and have better control over the drivers through the elimination of the passive components between the amp and drivers. In my experience, it makes a big difference and is worth the effort.<< Here is Nelson Pass of Threshold fame saying virually the same thing I have been saying in response to a put o him about bi-ampng without benefit of an elecronic crossover.Note that the time is over 24hrs AFTER my first post to you.I have explained this twice and now Nelson Pass has explained it.I have suggesed you get an O-scope and measure it since you don't understand it.Maybe you should download a program like Electronics Workbench and simulate it.I am sorry if I seem short with you but this is really quite simple and it seems like you are pretending to be obtuse.As regards your drawing >>mdeneen Insane Poster Posts: 329 From:Healdsburg, CA, California Registered: Jan 2001 posted 04-05-2001 12:15 PM quote: Originally posted by djk: Without removing the passive crossover parts and using an electronic crossover ahead of the amplifiers the 5W amp will clip 13dB before the 100W amp. --------------------------------------------- Respectfully, This is what you described above.<< I see where some of your confusion lies.Your drawing shows an electronic crossover and then passive filters after the power amp.This is not bi-amping.The drawing at the bottom of your setup shows what I am calling a duo-amp set up.To paraphrase myself and quote Nelson Pass: bi-amping "In my experience, it makes a big difference and is worth the effort".duo-amping "I'm not a big fan of bi-amping in this manner. While it arguably offers some improvement, my experience is that the improvement is small compared to the additional cost. Both amps have to swing the entire range of voltage driving both the top and bottom ends. I greatly prefer an actual crossover before the amplifiers, so that the high and low amplifiers only have to contend with the signal in their specific frequency band".I hope this is of some help.Perhaps you could visit with someone at your local community college and have him show you on an o-scope if you don't own one.

quote: Originally posted by jwgorman: DJK, So for the klipschophile on a budget, what electronic crossovers do you recommend? JWG http://www.audioasylum.com/audio/general/messages/114688.html I would use a custom assembled Marchand XM16.Crossovers are easy to build.They are very hard to design if you expect the best.I have a PWK passive crossover design for mating the K55V and the K77.This covers the K/B/LS/C/H from about 1963 to 1982.It is very simple and does not use the T2A autoformer.The XM16 will do the woofer to midrange crossover.For the best sound the electrical response of the filters will look strange but the acoustical response will be smooth and the system response flat.

>>Whether an electronic filter is used AHEAD of the two amps, or the two separate loads each have their own passive filter AFTER the amps, the fact remains that in both cases the two loads have been SEPARTED from each other and will dissapate their own power based on the current available from their respective amplifiers. And that furthermore, a single input voltage is capable making this happen.Cheers,mdeneen<< It would take too long to explain why you are wrong.I suggest you try your idea of using a 5W amp on the tweeter and a 100W amp on the woofer through the bi-wire inputs on the speakers.Without removing the passive crossover parts and using an electronic crossover ahead of the amplifiers the 5W amp will clip 13dB before the 100W amp.Use an o-scope and see for yourself.Hint as to where your thinking went wrong: You would be right if music consisted of single sine wave tones.

.040mH and 40µH are the same value.Decimal points don't always reproduce well.European standards omit decimal points.A 2.7 ohm resistor would be 2R7 and a 2,700 ohm would be 2K7.They would say fourty micro-Henries rather than point oh four oh milli-Henries.

>>This is incorrect. Two amplifiers driven by "the same input signal" will have wildly different power output curves based on their different LOAD IMPEDANCES ACROSS THE FILTER THEY ARE DRIVING. In the setup of two amps connected to the separate bi-terminals, one is driving a low-pass and will put out all it's power in that band, and the other is driving a high-pass and will put all its power in that band. If they are driven by the same signal, one will put out 5W into the HF network, and the other will put out 100W into the LF network. That makes 105W, not 5W as you imply throughout your text.Cheers,mdeneen<< You still don't get it.If in your first remark you had mentioned using an electronic crossover in conjunction with>>Those SET lovers, for example, can easily drive the daylights out of the horns with 5W, and then add an old NAD or ADCOM or Sony or what have you to the bottoms where all the power get's sucked. Remember, the power requirements from the amp is inversely proportional to the frequency, so this is what drains the smaller amps.<<then I would not have bothered to reply.Without an electronic crossover though your remarks are wrong.If you drive the inputs of a pair of 100W amps in parallel and each amp only sees a load in the high frequency or low frequency then at the voltage clipping point of either amp the SUM of the power will still be only 100W.To use your simplification: if the amp driving the highs is only putting out 5W because there is no load at low frequency then the amp driving the low frequency is only putting out 95W because there is no load in the high frequency.The 100W amp driving 5W into the high frequency load is still at the point of clipping because of the full range signal voltage it is being driven with and the 100W amp driving 95W into the low frequency load is still at the point of clipping because it is driven with the same full range signal voltage.Bi-amping and duo-amping are two very different things.Putting the frequency dividing network AHEAD of the amplifiers makes all the difference in the world.

Klipsch used to make an industrial version of the Cornwall II.The only difference was the K43 woofer.I heard them demonstrated side by side against the industrial LaScalas with the same K43 woofer.They smoked the LaScalas.Less coloration in the midrange. Deeper bass. Higher highs(K77 vs K79).No contest.Have never seen a Klipsch speaker with a chrome or aluminum dustcap.

>>mdeneen Here's a theory, or maybe just an opinion: Bi-wiring (that is using one amp) MUST be worse than single wiring for this reason: The HF and LF networks are in parallel - connected by the short straps. When you remove the straps and add say, 15ft of speaker wire to replace the strap, you are adding MORE resistance than the strap has to reproduce the EXACT same circuit. Adding series resistance is universally bad. This does not say the sound won't change, because it probably will - - but not in a good way.<< The difference in resistance is not what it is about.If anything the extra wire should be viewed as being in parallel with the main wire and thus decreases the total series resistance. >>Probably makes more sense to just replace the straps with good speaker wire. But again, it's hard to see what is accomplished because inside the box is all kinds of skinny wire and PC traces, which can't be any worse than the 2-inch strap.<< Again the resistance isn't the point. >>Using the terminals to Bi-amp (use TWO amps) is however, potentially very beneficial, because you can add more amplifier power, and you can assign amps by sound quality to LF and HF individually. (Downside, you need level control on the amps).Those SET lovers, for example, can easily drive the daylights out of the horns with 5W, and then add an old NAD or ADCOM or Sony or what have you to the bottoms where all the power get's sucked. Remember, the power requirements from the amp is inversely proportional to the frequency, so this is what drains the smaller amps.<< Now we are starting to get somewhere.Unless you are using an electronic crossover you are not increasing power in any meaningful way by adding two amps.Since both amps are driven by the exact same input signal they put out the exact same output signal.The amp that sees no load in the bass will have a fraction of a dB more power reserve in the power supply assuming that the supply is not regulated(a reasonable assumption in mid-fi).Even though there is no load as far as the current is concerned the amp still clips at the same point because the voltage is still there in the input signal.In a real bi-amp setup the electronic crossover removes the out of band input voltage so the amplifier does not have to amplify it.On a complex signal like music the voltages add. A 28V amp is 100W at 8 ohms.With an electronic crossover and two 28V amps a music signal of 56V may be reproduced.This 56V would be 400W in a uno-amp system.Paralleling the input of two amps without benefit of an electronic crossover is a uno-amp set up as far as the peak signal swing is concerned.From now on I will refer to this as a duo-amp set up so as to distinguish it from a bi-amp set up.Unlike a bi-amp set up a duo-amp set up does not allow you to use a smaller amp on the high end.With an electronic crossover on your Cornwalls(for instance)a 5W amp on the high end would keep up wih a 100W amp on the bass.In a duo-amp set up the full range signal fed into the 5W amp will cause clipping at uhh,5W.Plus maybe 1dB due to the increased dynamics from the unregulated power supply.Call it 5W + 1dB = 6.25W.In a bi-amp set up the 10dB of high frequency attenuation in the passive crossover is bypassed.There is less program material above the 600hz crossover point than below it.Because of this we can reduce our power requirement by about 3dB. 5W + 10dB + 3dB = 100W.Keeping in mind that 100W + 100W in a bi-amp set up = 400W in a uno-amp set up that means 100W + 5W bi-amped on a pair of Cornwalls = 400W uno-amped on a pair of Cornwalls.The passive crossover also has an insertion loss on the order of 1dB.That means the uno-amp set up now needs 500W to play the same volume level.What happens if we increase the high frequency amp from 5W to 20W? In the bi-amp set up as long as the high frequency is undistorted it tends to mask clipping in the low frequency amp.Measurements show that a uno-amp set up driven 6dB into clipping has more distortion than a bi-amp set up with the low frequency amp driven 14dB into clipping.That means that a 100W + 20W bi-amp set up on Cornwalls will be able to play undistorted the same volume level that a 1,000W uno-amp set up will on the same Cornwalls.A duo-amp set up with 100W + 20W will play as loud as the 20W amp + 1dB will play before the signal distorts. >>The "Bi-Amping" seems to be a cool, flexible thing. The "Bi-Wiring" seems to be less beneficial. mdeneen<< Now let us discuss bi-wiring vs duo-amping.Make no mistake.Duo-amping when properly done while not having the power advantages of bi-amping can still sound better than uno-amping.One of the main reasons duo-amping sounds better is because you are bi-wiring.Bi-wiring reduces intermodulation distortion caused by the resistance of the wire.In an experiment I bi-wired a pair of LaScala.Two sets of bananna plugs were used on the back of the speakers.A 6" long shorting jumper was constructed with the needed plugs.Wire lengths were on the order of 10'. The low frequency was wired with 12ga Monster Cable.The high frequency was wired with a 16ga twisted pair of silver plated teflon wire obtained surplus locally for $1 a pound (apexjr also sells it for $.14 a foot).The amplifier was the middle of the road Adcom GFA535.Removing the jumper wire was a revelation.The sound was much cleaner and more detailed.It was also much brighter. As the Adcom is a little dark sounding this was ok.Later the owner bought a better amp.With the Bryston it was a bit too much. Returning to uno-wiring made the sound collapse.Bi-wiring with a small resistive pad on the high frequency was the trick. JWG tried bi-wiring on his Belle with his McIntosh amp and had a similar experience.It was too bright.Duo-amping gives us these same benefits of bi-wiring wih two more advantages.A) level controls on the amps save us from fooling around with a resistive pad on the high frequency. reducion in intermodulation distortion in the amplifiers.While the amps still clip at the same point due to the same signal voltage being fed to them the reduction in bandwidth of the delivered current to the load reduces intermodulaion distortion.In summary.Bi-amping is best.Bi-wiring reduces intermodulation distortion in the wire. Duo-amping reduces intermodulation distorion in the amps and also gives us the reduction in intermodulation distortion that we get from bi-wiring.Some means of adjusting the levels will be required whether we bi-amp, bi-wire, or duo-amp.The point at which the amp driving the high frequency clips will determine how loud the system can play before distortion sets in.90% of the people that I have met cannot hear in any meaningful way. I have had salesmen in high end stereo salons play me their best system and not notice one side was dead.A salesman in a store in which I ran the service department would routinely hook the Klipschorns out of phase. He hated Klipsch.None of the other salesmen (or customers)ever noiced.So can YOU hear any of this.If I say no I will have a 90% chance of being right.

A couple of notes here.A speaker with an No=1% is only 92dB/W/1M in half space.The size of the entrance hole of a horn is not usually the throat size.The area of the slots of the phase plug directly adjacent to the diaphragm constitute the throat for pressure distortion calculations.Doing this for a K55 vs an M200 shows that an M200 will have 10dB less distortion at any given frequency and level with respect to the K55.I think I can hear 10dB.As far as SPL goes the worst case situation for the 6Khz crossover on a K55 vs the 3.5Khz crossover on an M200 gives a 6dB lower distortion spec due to reduction in bandwidth.Total worst case distortion would be a total of 16dB higher with the K55.A K400 cut off at 1.375" internal height will mate up with a JBL 2328 2" throat adapter.The 2328 will need to have about .125" filled with bondo and hand rasped to mate with the K400 internal width.To mate with the shorter K500 about .0625" will need to be removed from the 2328.So I guess the question is: How much time and money are you willing to spend for 16dB of distortion reduction in the octave your hearing is most sensitive in? A pair of M200 and a pair of 2328 cost less than $500.

Since your woofer is open I think you should investigate it a little more before sending Klipsch $94 for a single K24 that will not sound like your K22.Take an exacto knife or single edged razor blade and remove the dustcap.Leave an 1/8" or so where it meets the cone.What have you got to lose, you know it's open right? Look at where the braided tinsel leads go through the cone and crimp on to the voice coil wires.Scrape a little insulation off the voice coil wires and check again with your meter.I bet your coil is ok.A speaker re-cone shop will replace the tinsel leads and dustcap for about $15 or sell you the parts for about $5.

>>John Albright Those ARE the late drivers. I have 2 of those and one of the early K-55-Vs. I can't hear a difference other than the fact that the newest late driver has less output than its twin. I have had the disphragm replaced and found the voice coil was rubbing apparently from abuse. << The K55V with solder lugs sounds better than the ones with spring loaded terminals because the connections can't vibrate.The Atlas PDMR, the Atlas model designation for the new phase plug design, both measures and sounds different than the K55V. >>John Warren What the big deal with these drivers?? I've got a pr of them on LaScalas I don't think they sound a any different than the K55M (they all suck).There is no magic fix here---> you need a midrange with a bigger throat. it physics nothing else, stop fooling yourselves<< We are in total agreement.These drivers are from the MCM1900 which originally used the Gauss HF4000 2" throat midrange driver.My favorite 2" midrange driver for the K/B/LS is the Community Light and Sound M200 ftp://ftp.voicenet.com/communit/specs/new/m200.pdf This driver sounds much better than the current crop of titanium 2" stuff.>>Al Klappenberger As to the bigger throat, If you are going to have the same taper and start with a biger throat, you must wind up with a bigger mouth.<< For the same taper rate if you start out with a bigger throat you end up with the same mouth area and a shorter horn.Done it many times with the K400.See figure 5.11 in Acoustical Engineering by Olson.Shows a 100hz horn with different throat sizes.Absolute best horn reference book.