Marvel

Travis, I was trying to find a good explanation of a waveguide. The easy answer is that it is a specially designed horn flare. But not quite. Different companies now use them. JBL, Yamaha, Mackie, Genelec. I will have to dig out some reference material unless someone else posts other information.

Maybe you should just get some Genelecs and be done with it. Building in the waveguides is pretty cost effective. Bruce

I suppose you like those NOSValves VRDs too.

There ya go Craig, talkin' up another forum members work. [] Bruce

I'll interject a post that I found by Tom Danley, about time delay. Some has to do with the phase response of a signal going through a speaker. This all makes my head hurt, but I thought it might add more useful info to this thread. I don't remember where I found it, but it is one of those things I saved. Consider how a normal "perfect" speaker spreads out a signal in time. Make an imaginary signal that has equal amplitude content from 100 Hz to 25 Hz, a specific waveshape which has this property. Take an imaginary perfect flat response speaker who's upper and lower cutoffs are way past our needed bandwidth. This mass controlled "flat" response speaker has a -90 degree lag or delay, at 100 Hz the phase shift is equal to a source 2.83 feet behind the speaker cone, at 50 Hz, the delay is equal to 5.66 feet, at 25 Hz is equal to 11.32 feet and so on. This test signal's wave shape defines the input "time" of each frequency component. When reproduced, the highest frequency component at 100 Hz emerges from the radiator 2.5 ms AFTER the signal arrived at the driver terminals. At 50 Hz, this component emerges 5 ms AFTER the signal hit the terminals and at 25 Hz, the signal emerges after 10 ms and so on. With the driver spreading the signals frequency components out in time, it is simply not possible to retain the same waveshape as the input signal, lower frequencies arrive progressively later in time than the original signal.. Any signal reproduced is done so with the spectrum rearranged in time by the drivers acoustic phase response. If one had a driver which had a very strong motor or a normal motor but very low moving mass, one gets an "over damped" response. This term is from filter design meaning that it is not optimally flat, excessively damped, rolling off too soon and gradually Should the slope of the response reach 6 dB per octave, the driver is operating in the Velocity controlled mode, while the response is not flat, the acoustic phase DOES track the input signal (zero degrees) and the different frequency components are not spread out in time. The waveshape of the input signal is more closely replicated as the frequency components are in the original "time" although the amplitudes are off 6 dB/oct. Each 3 dB /oct change in the slope produces a 45 degree change in phase. An over damped response more closely retains the time information where a flat amplitude response cannot. A proper LF horn can have flat acoustic response AND roughly zero degree acoustic phase. For a person more sensitive to "time errors", they will likely find an over damped system more realistic. For a person more sensitive to "amplitude errors" the traditional "flat response" system will be more satisfying. For the person lucky enough to have heard a proper lf horn system, you have heard that one can have "lightning fast" sounding bass and still make your pant legs flap.

That may be your room, but I think you Photoshopped that equipment in.[] Bruce

Tony, There is a long thread on the lansing heritage site about the performance series. They apparently rock the house. Not a horn presentation, but very, very good. The biggest problem is how JBL doesn't market their products very well. Bruce

If you are in California, check out: http://www.speakerrepair.com/ You can at least give them a call. Bruce

Can I assume you mean the surrounds on the speakers? They can be repaired or you can get new drivers. The 'rubber boots' or foam surrounds deteriorate over time. Bruce

Hence my comment that it would be easier to go the other way ( EL34 to 6L6). I can only imagine that most older tube gear way a real cost/performance ratio and the power tranny was close to the limit already. Not everyone overbuilds. When it came to iron, the cost went up quickly. Still does. Bruce

That's because your browser draws the size of the table statically and it cannot resize the image until the whole thing has been downloaded...then when the image finishes loading and resizes, there is nothing to tell the table to resize...I bet on a page refresh (when the images are already cached) that the tables go back to normal size. No cigar for you. IE will resize as the pages load, but Firefox will not, even with a refresh.

Larry, I noticed the dust too. But Neo said he just was placing them back and hadn't hooked up all the cables yet as well. ...and I agree about all the shadows and highlights. Bruce ps Listening to Hilary Hahn playing Bach Concertos with the Los Angeles Chamber Orchestra. Sounds great! Very relaxing for a Friday evening. Doesn't get you all wired up and tense like that metal music[]

Tom, Korngold=excellent compositions! Bruce

You could change the color depending on the mood you wanted to set. Have you noticed that the forum software resizes the images but the table/frame stays the same size as the original image?

http://www.angelfire.com/wi/blindfaith/grechbiog.html Here you go Artto.

Damon, Are you rsupposed to be all dried in before snow falls up there? Hope they can move along a little faster (with quality). Bruce

IC preamp stage and LEDs for biasing the output tubes. Pretty novel. 12 VAC power input. No wonder it is such a low output amp.

Those Moondogs look great Neo. I love that burled wood on the bases. Bruce

Dee, I have been told that with some minor adjustments that you can go the other way. Like put 6L6GCs into an ST-70. There would have to be some adjustments made, but there wouldn't be the load on the heater windings. Switching TO an EL34 would add almost two amps load on the heater windings (assuming two tubes per side). One of the guys on the DIYTube forum pust in 6L6 tubes instead of EL34 tubes on one of Shannon's boards. Maybe he used 6L6 tubes on the EL84 based amp. Added wires off the board and ran them to octal sockets instead of the pc mount 9 pin sockets. Then he had to make adjustments with the PS to have all the voltages split out correctly. Bruce

Duke, Did you get those (pic is familiar) from the dude on the Lansing forums? The guy who had 8 sets of those from movie theaters? Bruce

They went out of style about 21 years ago, unless you do a lot of yachting. [] One of the best, cheapest shoe sotres near me carries Sperrys. They are still a great comfortable shoe.

I keep telling ya they're elephant cheeks!!![]

I have always enjoyed listening to Mark O'Connor, more widely known for his country fiddle playing. He has also written and recorded more classical styled pieces. Whe he came and played his "Fiddle Concerto" (5 movements) with the Chattanooga Symphony he had it plugged in. The main benefit was the slight improvement in gain over the rest of the orchestra. The sound was still very much acoustic. I'm with D-MAN on this, and can't remember anyone specic performer who plays electric violin with an orchestra. Of course most instrument were made amplified to be able to be heard over other instruments. The kalimba or thumb piano being one. You can barely hear it in a room of folks talking. Then the players realized they could change the sound of their intrument and things haven't been the same since.

Doesn't MS Photo Editor come with XP (the OS) or just with MS Office? If you have Photo Editor, you just open the photo and go to the image menu. Under that is resize. If you leave the "allow distortion" box unchecked, as you change oone value the other will change as well. Attached are a couple of screen shots stuck in as one image.

I'm thinking you could resize your pics before uploading them to the server. Or Klipsch could prevent uploads over a certain size. A 1.7 meg jpg is too big. It's nice that their software resizes the pics, but they take forever to load the first time. Making is 600 pixels wide would do wonders for the speed. btw, nice Fisher. Bruce