TBrennan Posted July 2, 2003 Share Posted July 2, 2003 Paul---At MGM in the early 1930s engineers monitoring a soundtrack of Eleanore Powell tapdancing noticed double-taps where there should have been single taps. John Hilliard traced this to the 12' path difference between the drivers in the Western Electric horn-loaded monitor speaker. At the time he investigated the double-taps Hilliard determined that a 3ms delay was inaudible with a crossover in the 500-800hz range. Hilliard then led the team that developed the Shearer Horn which greatly reduced delay down into the range Hilliard thought acceptable. But any delay at all evidently stuck in Hilliard's craw because 10 years later he developed the Altec VOTs which totally eliminated driver offset. Hilliard was the Zeus of the Horn Gods. His home stereo speaker system was a huge infinite baffle built into the 2 story stone fireplace of his cathedral ceilinged house. Each channel consisted of 2 Altec 803B 15" woofers in a 100 cubic foot concrete enclosure built into the fireplace. Above 500hz an Altec 802 driver on 511B horn took over. Impressive. I have pictures of it but never found any pictures of the system on the web. Quote Link to comment Share on other sites More sharing options...
sunnysal Posted July 2, 2003 Share Posted July 2, 2003 I would love to see that system tom, any chance you could scan and post it? regards, tony Quote Link to comment Share on other sites More sharing options...
jruhnke Posted July 2, 2003 Share Posted July 2, 2003 ---------------- On 7/2/2003 4:21:02 PM DeanG wrote: ...Remove the (front and rear) grills... ... I lined (the midrange and tweeter baffles) with soft foam weather stripping. ... I increase rigidity by (completely replacing the baffles with different material and fasteners). (Thousands of units were shipped mis-wired.) ... ---------------- What a compelling endorsement of the original design and build quality! On the plus side, these units can be acquired inexpensively. Here's a pair that may still be available for a reasonable price: http://pub42.ezboard.com/faudioforum83468frm5.showMessage?topicID=84.topic Jim Quote Link to comment Share on other sites More sharing options...
TBrennan Posted July 2, 2003 Share Posted July 2, 2003 Tony----There are a couple of pictures and a description of the system in the book "How to Build Loudspeaker Enclosures" by Badmeinof and Davis. This was printed in the 60s and was the first text alot of us old hornies had. Lots of horn plans; Altec 825s, Jensen Imperial, Klipsch Shorthorn and others. Anyway my copy is packed away, I'm getting ready for a move. Quote Link to comment Share on other sites More sharing options...
Deang Posted July 2, 2003 Share Posted July 2, 2003 Production problems began at Dahlquist after Jon Dahlquist was in a near fatal car crash. I imagine everyone was pretty shook up. The company was eventually sold, and things pretty much spiraled down-hill after that. Old DQ's are like Scott amps -- don't even think about plug and play. They need some work after 30 years -- they're not Klipsch after all. Quote Link to comment Share on other sites More sharing options...
Tyson68 Posted July 4, 2003 Share Posted July 4, 2003 Back in the late '70's, there was a company called ULTRAPHASE that sold their speakers by demonstrating the time correctness by having 2 drivers playing white noise. They would start out a few inches apart and slowly pull them together until the voice coils were inline. While the effect may not be audible in music, with white noise you can definitely hear it change tone/pitch and then sync when the voice coils are inline. The speaker itself had a slanted design, like a THIEL speaker but midrange and tweeter were set to fire horizontal, with all voice coils inline top to bottom. My Forte II's took their place and the ULTRAPHASE sit in a corner now, so I guess that says it all, no? Quote Link to comment Share on other sites More sharing options...
Parrot Posted July 4, 2003 Share Posted July 4, 2003 Thanks, Tom. Are you moving into a place with a two-story stone fireplace? Quote Link to comment Share on other sites More sharing options...
Manuel Delaflor Posted July 4, 2003 Share Posted July 4, 2003 Please correct me if Im wrong. Time alignment is rather complex, I understand more or less the theory (I think) and that some are aligned with the possition of the drivers and others with delays in the crossover section. But what I don't understand is this, a time aligned speaker is just aligned with itself, so the only way to hear the phase coherence is to listen to one as a mono source. Because when you introduce another speaker they will certainly not be at exactly the same distance from your ears in a perfect triangle, so, where does that leave time alignment? Quote Link to comment Share on other sites More sharing options...
TBrennan Posted July 5, 2003 Share Posted July 5, 2003 Paul---No 2 story fireplace, I'll be getting an apartment. Maybe a loft. Quote Link to comment Share on other sites More sharing options...
djk Posted July 5, 2003 Share Posted July 5, 2003 http://64.154.92.195/forums/hug/messages/51409.html Put me down in the camp that can hear the difference too. Quote Link to comment Share on other sites More sharing options...
foldedhorn Posted July 5, 2003 Share Posted July 5, 2003 If anyone does not understand what time aligned means or sounds like I am damn sure that any of the 16 year old pre puberty sales associates can explain and surly demonstrate this at any Best Buy store. Because I am most confident that Mr. Klipsch crawled out of his grave and personally trained each and every one of them. Also, I understand time aligning can best recreated in a room that is about 1000 feet square with absolutely no sound baffling, and with a father yelling at his 8 year old son to stop hitting his sister while his soccer mom wife has her head stuffed inside of and oven trying to decide if is self cleaning or not. Yea, time aligning means so much to these people after all that is why Klipsch has directed there sales to this type of clientele.. No? Quote Link to comment Share on other sites More sharing options...
djk Posted July 5, 2003 Share Posted July 5, 2003 Did we forget our meds today? Quote Link to comment Share on other sites More sharing options...
Deang Posted July 5, 2003 Share Posted July 5, 2003 LOL Foldedhorn -- I can't believe you're still freaking out because Klipsch decided to sell Synergy at Best Buy. At least now, Best Buy has something in there that actually shows how bad the Bose Acoustamess System really is. Quote Link to comment Share on other sites More sharing options...
Flux Posted July 6, 2003 Share Posted July 6, 2003 If time aligned speakers aren't time aligning, then why do they sound so different from other speakers? Quote Link to comment Share on other sites More sharing options...
sunnysal Posted July 6, 2003 Share Posted July 6, 2003 flux, that is the hard part, to know whther a speaker sounds different due to time alignment or other factors that differ speaker to speaker; drivers, x-over parts and design, cabinet desgin and construction, etc., etc. the bell labs experiments had the same drivers being adjusted in terms of relative position fron to back to establish whether the effect of time alignment, and that only, could be detected. it seems to me that listening tests between different speakers will get someone nowhere. the correct way to test would be to focus on the time alignment aspect only. moving drivers forward and backward is a good way to do this, I suppose someone could also take the same speakers and swap x-overs, that would be another way. the trick is to vary only one variable to see if differences are detectable. one cannot accomplish that by listening to two different speakers. I remember that John curl tried some experiements on his k-horn x-overs to try to address phase/time issues but never got it where he wanted it. regards, tony Quote Link to comment Share on other sites More sharing options...
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