Jim E

Here is a great picture from one of the Forum members that can help visualize the construction.

---------------- On 1/22/2005 6:59:28 PM jwcullison wrote: I have a couple of question regarding this drawing. Describe the "Blocking 3/4 by 3/4" on you side view On the bottom, is there a bottom piece of wood, then another piece of wood on top of that, then the port space, then the port shelf. In other words, is there two pieces of wood for the bottom? If so, Why? So what Would be the internal volume of the cornwall not subtracing the port shelf, drivers, or any insulation/lining? Nice drawing, I hope others chime in so that this could be completely understood. jc Thanks ---------------- Thanks JC, The interior has blocking in all four corners. The front and back have full length blocks also. This is for mounting the front (inset 5/8") and rear baffles (mounted flush). The back is removable with screws, the front is attached permantly and glued. There is only one panel of material at the bottom. The bottom corner blocks have two side supports above them that space the port shelf to the proper dimension. Not counting drivers, blocking or the port shelf it looks like 6.388 cuft.

---------------- On 1/22/2005 6:39:28 PM IB Slammin wrote: ---------------- On 1/22/2005 4:09:07 PM Jim E wrote: It would be nice to have the riser or "base" dimensioning of the Corns as well. Perhaps I could include the various changes between the earlier and later models. ---------------- Riser from '75s: 23-3/8"W X 14-1/2"D 1-3/4"H +/- 15/16" in from front ---------------- Thank you. I'll plug those numbers into the drawing.

---------------- On 1/22/2005 10:03:21 AM Daddy Dee wrote: O.K. I've got two questions unrelated, except that they are connected by my ignorance. I'm considering taking on a modest newbie DIY project to recase the tripath amplifier in the Sonic Impact amp. It's level of difficulty appears to be not too far ahead of my skills, which are next to nothing. Am trying to figure out which potentiometer to use for volume control. My understanding is that this will work by attenuating in input signal. One poster I was reading used a 100K attenuator. In this usage, is the term "attenuator" interchangable with "potentiometer". Also, what would be the expected difference in results if a 25K pot was used instead. Another project on the horizon (sure, Dee) is the PWK minibox. It calls for 25K pots to build it. Another related question...What is the difference between a potentiometer and a rheostat? Some DIY threads I read talk about how different pots affect the sound. I tend toward the wire is wire philosophy, assuming the wire is decent. What about pots? Have been doing a little reading on the internet about the use of tripath amplifiers. What is the difference between a "class T" amplifier and a "class D" amplifier. I notice that the upcoming Klipsch 2.1 iFi uses a "class D" amp. Any help is appreciated. If speaking technically, please type slow. ---------------- Whether you use a stepped attenuator or a potentiometer, audio controls are usually logarithmic taper types when used directly with an analog signal. Linear taper pots are more common where the signal is used for voltage or current control on an electronic circuit, digital chip or VCA (voltage controlled amplifier). Generally it is better to stay away from wire wound controls. Cermet and stepped (with fixed resistors) components seem to be the most quiet and have better precision.

---------------- On 1/22/2005 9:53:10 AM Marvel wrote: Jim, I was under the impression that the LS used ring nails for the butt joints, like where the top of the cabinet rests on the two side pieces. I think there are very few, or no, screws in the LS cab. Klipsch didn't intend for you to take it apart, as access to the drivers is available in the finished enclosure. I didn't think the LS used staples at all, although going back over Andy's notes, he says they did. Since there are no cleats in the LS, so the most difficult joint to nail is the front "V" on the doghouse and probably where the back parts of the "V" attach to the two parallel side pieces on the doghouse. Perhaps the staples were used there. If Andy is around, I'm sure he could provide more details. Marvel ---------------- Thanks Marvel, These small details are interesting. Andy also stated he made a jig for the LS doghouse that allowed him to use glue only on the sharp front angle. The factory nailed this area. Ring shanks make sense but I have found 1/4" crown staples hold very well and the gun can be adjusted to sink the staple just below the surface. A little color matched putty and the staple disapears. The down side is these staples are almost impossible to remove if you screw up. I don't believe the fasteners do much after the glue sets. Jim

The rear panel covers the rear edge of the LaScala top and bottom. So, the top of the bass bin is 23" deep (front edge is concealed by the upper baffle) and the bottom is 23 3/4" deep as you stated. The rear panel extends from the top of the doghouse panel to the bottom of the lower doghouse panel. This makes the rear cover to also be 23 3/4". The bottom doghouse cover ends at the inside edge of rear cover.

---------------- On 1/22/2005 1:36:48 PM Marvel wrote: Seeing as how Andy really pays attention to detail and since I don't have a real LS in front of me. I now question my correction I posted. Can anyone who has one tell me if the back of the LS cabinet covers the back edge of the bass bin and the back edge of the bottom? It is hard to tell from the drawings. Marvel ---------------- A picture perhaps.

It would be nice to have the riser or "base" dimensioning of the Corns as well. Perhaps I could include the various changes between the earlier and later models.

As there are a few folks looking for Cornwall plans... There were several versions of the Cornwall this will take a little input from a few of you Cornwall owners. I looked up Andy's measurements (thank you Andy)and drew up this preliminary file. The version that Andy measured has two port openings. This version has three. If anyone would care to contribute some accurate measurements on the driver locations/openings and verify the overall dimensions shown, I will be happy to finish this off and post it in high res pdf format.

---------------- On 1/21/2005 8:03:34 PM m00n wrote: so have we come to a conclusion on this? MDF or Ply? ---------------- mOOn, There is no simple answer and I doubt there will be conclusion. Klipsch is one of the very few manufacturers that use plywood for speaker cabinet construction (outside of road gear). I respect their effort at keeping these true to the original design. It is my belief that material should be selected for the application, available tooling for the job and the individuals woodworking ability. Material cost for DIY speaker cabinets is somewhat low no matter which material you choose. I have a related question. I read on this Forum that LaScalas and Belles were assembled by hand with glue and mostly 1/4" by 1 1/8" crown staples. I think this was posted by HDBRBuilder. In this thread I keep reading how screws don't work going in on edge without pre-drilling MDF. While pre-drilling is always a good idea (even in plywood), where are there butt joints on these cabinets that require the use of any "edge" screws? I'm just curious because staples work just fine on MDF as well. BTW I use coarse thread drywall screws on MDF and plywood and have rarely experianced any problems on either material.

Mick, In the past I have taken 511 and 811 horns to the local powder coating shop. They can produce any type of finish you could want from flat to high gloss. Even hammertone. The process is very durable and looks fantastic. I'm sure the type of finish does'nt effect the sound much. Altec painted these flat green, hammertone green and semi-flat black. I would choose what looks best for your app.

---------------- On 1/11/2005 8:48:15 PM thebes wrote: All right now we're cooking! Thanks Craig, Good catch on the Borg's Mr. Taylor and JJ in addition to god advice you made reference to Kelly's Heroes my all time favorite flick! I'm humming the theme song right now-"burning bridges tumbling down..." Suprisingly though no one has caught my oh so subtle literary reference. Could of sworn we had a more literate crew hanging around here. ---------------- That was elementary dear Watson...

Wolfram, Sure. That would be fine. Jim

---------------- On 1/8/2005 6:42:18 PM DrWho wrote: The Behringer has optical ins and outs on it...Have any of you guys connected your CD players digitally to the device? It's always important to try and reduce the number of AD/DA conversions that go on in the signal chain. ---------------- Yep...it's true. Keep the signal in the digital domain as much as possible. With recent advances in amplifier technology it is possible to have everything from your source material to your speaker drivers digital (that includes eliminating passive crossovers BTW). Potentially the only analog elements in the recording/playback chain could be the microphones/pick-ups and speaker(s)elements. I'm not saying this is good or bad but the technology is here. Analog playback and recording will become more and more of a "cult thing" once all the equipment manufacturers go full digital.

---------------- On 1/8/2005 1:48:55 PM dubai2000 wrote: Jim, I think I am getting there , the only 'problem' might be that most of my power amps do not have input controls, so I suppose I'll have to turn down the Behringer's output (if necessary) while keeping input as close to 0 dB as possible? Test CD: Is there any you can recommend? Wolfram ---------------- Wolfram, That's about it. Use the output level adjustments on the Behringer. As far as the CD, I have no recomendation. You could use a simple sine wave tone generator as well. Jim

---------------- On 1/7/2005 9:43:49 AM dubai2000 wrote: Jim, yes, the preamp does have multiple inputs, so eq 'll go between pre- and power amps. Does this change of noise floor mean I'd have to adjust the eq's input level when I turn down the volume (supposing the Behringer allows this without too much complication)or and how much noise (hiss?) would the unit produce (after all Khorns are kind of sensitive)? I suppose I'd adjust input in a way that the eq reaches its max when I reach my upper volume level? BTW: thanks a bunch for your patience! Wolfram ---------------- Wolfram, You are welcome. You will have to try it out. The amount of noise (if any) will depend on too many factors to guess. You may find there is no noise at all. My experiance with Behringer products has been good and they build their equipment to fill as many applications as possible. I don't think you will have to adjust the input or output on the eq once you have it setup. You are quite correct, horn systems will reveal everything...good or bad. Every system is different and I am not familiar with your setup but this procedure may help. You will need a decent test CD. The idea here is to get the Behringer in/out levels up to a good working range. Set the input to the Behringer with a 1 kHz tone @ 50% modulation off the test CD fed into your pre-amp. Set the volume control to the highest setting you would normally use on the pre-amp (be sure to turn off and turn down your power amp first) and adjust the input to the eq so that it indicates 0 dB. Now adjust the output on the eq to read 0 dB. Play some familiar reference material through the pre-amp and turn on your power amp with the input controls at minimum. Adjust the inputs on the power amp until you have enough level. I hope this is not too confusing.

---------------- On 1/6/2005 2:15:46 PM mafuta wrote: Best 40 bucks you'll ever spend.1 oct increments are really a bit crude + you also get some signal generating capability for the extra.Jeez add a $50 Behringer calibration mic and you have several kilobucks worth of capability for the price of a a a....farm in Chad. ---------------- I've tried this analyzer software. I seems to work fine but requires a considerable amount of computer resources to run full bore. My preferance is the Spectra 32 software for PC application. As far as using the Behringer mic or any other electret condenser type, you will need an external mic pre-amp with phantom power. This "type" of mic requires external power that can range from 5 to 48 VDC depending on the manufacturer.

---------------- On 1/7/2005 4:01:49 AM dubai2000 wrote: Jim, no tape loop and if I read your post correctly inserting it prior to volume control (i.e. between sources and preamp) should be more convenient, correct? Wolfram ---------------- Wolfram, Not exactly. If you don't have an insert loop, it would be better to put it between your pre-amp and power amp. Your pre-amp most likely allows you to select your source so this would be more convenient. The point I was making is that the eq has input and output level adjustments. If the input level to the eq changes you also change the noise floor on the output of the eq. In other words...at low listening levels you might have more noise on the output. In most cases it is best to have the volume control just prior to the power amps. Does this make sense? Jim

---------------- On 1/6/2005 11:43:35 AM dubai2000 wrote: I understand that Mike has hooked up his unit between source and preamp. I could use a switch box before the Behringer to have a kind of multiple input into the unit (actually I have done that with some other 'toy' and it works just fine) so is that better than putting it between pre- and power amp (like would I have to change settings of the unit when changing listening volume?) and what if I swap power amps - will I have to readjust settings on the Behringer? ---------------- Wolfram, You could hook up that way. It would be better if you could insert the unit in a tape loop or somewhere that the volume control doesn't affect the in/out levels. This would help keep the in and out levels to the EQ at a more constant level. If you can't hook up this way, it's ok. The Behringer eq is professional gear so it can take much higher input levels than most home gear can produce. In fact balanced line pro gear usually has better noise specs if they are run at 0 to +4 levels. Most amplifiers should not require more than output level adjustment to compensate for different gain structure between the old and new amp. A good amplifier should be "flat" throughout the audible spectrum so additional changes to your eq settings should not be required. Jim

---------------- On 1/5/2005 8:04:33 AM dubai2000 wrote: Jim, the question might be stupid, but when doing what you have described does one (only) stay in front of the listing position or also behind one's favourite sweet spot? Plus there is an opening to right of my listening position, but not to the left. Wolfram ---------------- Wolfram, Not a stupid question at all. Yes, you can but remember that having hard or soft surfaces near the mic will give less than accurate readings and the area behind your "sweet spot" may not be an area of concern. I would measure the area and note the readings but probably not include it in the average. You should take readings in at least the largest acceptable listening area. The point to moving the mic is that it will help reveal problem areas. This can also assist you in speaker and furniture placement. It is amazing how much the response can change in a room by moving a few things or toeing your speakers a few degrees. Experiment and become familiar with your room's acoustic space. Expertise in this stuff is gained by hands on practice and observation. Just as a note, you should maintain the same mic height throughout the process. Jim

Mike, I can appreciate what you are saying. Setting up any room can be difficult with so many variables. One trick you might try is averaging. In setting up auditoriums and theatres I use four mics with a timed multiplexer but the same thing can be done with a single mic. Fire up the RTA and move the mic to several positions in your listening area and observe the display (one channel only). You will most likely find that the RTA will display differently in each location. Copy the readings (boring but very tedious) from several mic locations (ignore any mic position with excessive dips or peaks) and calculate the average for each band. Enter the offset average manually into the EQ and have a listen. Try this on each channel and compare the readings. This process should yield a larger listening area and smoother response. It takes a bit of time but experimenting is fun is'nt it? Jim

Michael, Very true and correct. Many audiophiles and others do not care for digital processing and nothing much is analog about this gear outside of the input and output stages. The EQ is DSP based and is "software driven"...and it is upgradable as well through it's MIDI port. Speaking of MIDI, multiple units could be connected for additional eq's and/or additional processors. In a multi-channel system one could have many settings that could be linked for simplified control. Jim

Mike, Seems you got it right the first time. The Behringer mic is used vertically or to be more precise at 90 degrees to the sound source. This is done because there is a slight pressure build up at high frequency. Using the mic pointed towards the speaker would result in a +3 dB rise at the top end of the spectrum. This would also be true for most 1/4" and 1/2" electret condenser omni mics. For $60 direct from Behringer the ECM8000 is an excellent value. In my opinion this mic is a best bet for home use. The reason for the 6" to 10" above seated ear height places the mic slightly off axis from the speaker and away from the floor. This is also a good height for those with overstuffed furniture. Jim

The Behringer EQ looks like a great deal for the money. I have used several of their products and found they perform very well. Quiet, clean and cost effective. Having multiple memory settings is a definite bonus for those who use their systems for both 2-channel audio and home theatre. I just wanted to throw in a couple of points that may help in EQing your system. There are so many variables involved I cant cover everything but for those who are new a few points could shorten the journey into sonic nirvana. One thing I cannot stress enough, EQ cannot correct for poor setup or marginal components. It is vital that all your equipment including your speakers are working correctly and adjusted as close to optimum as possible. 1) When setting up your system with an RTA determine the correct alignment of the microphone. Some mics require vertical positioning (capsule towards the ceiling) such as the Beyer MM-1. The mic should not be placed near reflective objects or near sound absorbing items such as padded upholstery. The mic height should be about 6 to 10 inches above ear level in a seated position. A word of warning, use a good quality instrumentation mic. The Behringer mic looks damn good for the price. Ive seen a few comparisons and it scored well against several 3 to 4 hundred dollar mics. 2) The manual for the DEQ 2996 is quite correct in advising the 100 Hz limit. FFT analysis can give misleading readings on low frequency. I believe this is due to the sample rates being too short in relation to the low frequency wavelength. There are workarounds for this but it is a bitinvolved. 3) Before setting any equalization check the existing response of your system with all controls set to a flat position. Position all furniture in the room into the normal setup. This is the time to optimize your equipment. Using pink noise, set the output levels approximately 10 dB above the ambient noise level. I typically set the output level to 85 dB C weighted. The pink noise should be fed into the front end of your system. Set the crossover adjustments (or taps) for the flattest response. The key here is to eliminate any abnormalities in your system and set a baseline for gain structure and channel balance. The equalizer should be adjusted for unity signal gain. 4) A subject of debate. What is the correct setting or curve for equalization? Of course being able to reproduce 20 Hz to 20 kHz is a goal however, listening to a system set flat usually sounds too bright. It has been my experience that using the THX curve (which was derived from the SMPTE ISO 2969 specification) works best for me. Simply stated, response should be flat from 50 Hz to 2kHz rolling off at 3 dB per octave above 2 kHz (plus or minus 2 dB). One a 1/3- octave display this would relate to -1 dB per step. This is the standard used in motion picture theatres and dubbing stages by Dolby, THX, Sony and DTS to name a few. In smaller listening areas the roll-off may be extended out to as high as 4 kHz. Using this curve in a home theatre setup should give the best sound as all films are mixed on a sound stage that is calibrated to this standard. To the best of my knowledge there is no modification to the audio on DVD or any other format from the original film sound track. Ultimately you will find an EQ setting that works for you. The one I described is a good starting point for home theatre. In my case, it also works well for 2-channel audio. With the advent of DSP based equipment many of the old problems in using equalization have been reduced or eliminated. It is still a good idea to tweak your room acoustics to minimize early reflections and reduce nodal problem areas but EQ will smooth out most of the lumps. Just be careful with extending the high and low frequency response of your speakers. The components do have limits and it is easy to burn out a driver if over driven. A quick disclaimer, I have never been a straight wire with gain type. Being a tweaker by nature I am only expressing my opinion and personal experience. Jim

Chinoloco, For what it's worth, I still see no purpose in "bi-wiring" outside of reduceing the resistance of your wire run. That can be done quite easily by going to a heavier gauge of wire. If anything bi-wiring could double your chances of picking up radio frequency interferance and/or electrical noise. It's pretty hard to confuse those electrons, they seem to know where to go. As an opinion only, try bi or tri-amping your setup with adjustable delay active crossovers. It is a little pricey and can be difficult to setup but it is the best bang for your buck. Jim