boom3 Posted January 7, 2008 Share Posted January 7, 2008 I'm not looking to build these, but this has always been a mystery to me. The Imperial was a backloaded horn that was popular in the 50s. Never was a serious competetor to the Klipschorn. The mystery is, why are there two windows in the chambers above the "throat"? It would seem that those chambers should be closed off to preserve the horn loading. My thought is that having an opening into each makes them function as a classic Helmotz resonator and may have given the impression of "more bass" Any thoughts? Imperial plan.pdf Quote Link to comment Share on other sites More sharing options...
HarryO Posted January 7, 2008 Share Posted January 7, 2008 Weird you brought this up. I ran into a factory built pair of these at the local Goodwill less than a month ago. $19.95 for the pair. Very nice condition. They had the H225c Pro 12 Co-axial w/balancing network in them. I bought them for the 225s as they sell good in Asia. I listened to them for less than an hour before I stripped them out. The rear sides porting was shallow and the cabinets sounded very hollow. The 225 is a decent sounding driver but in these cabinets it was inefficient. It's why it probably didn't go over. They may have been ok with a different driver configuration I disassembled the cabinets to get a good look and I was wondering the same thing about the openings in the chamber and summised it was because of the drivers used. Harry Quote Link to comment Share on other sites More sharing options...
ajsons Posted January 7, 2008 Share Posted January 7, 2008 Harry, those might not have been factory builts. Here's a quote from "How to Build Loudspeaker Enclosures", page 101, describing the construction of the Imperial, also showing the plan that Boom3 had attached.. "While not shown in the sectional view, the access openings to the speaker and network compartments are covered with 3/4-inch plywood panels about 2 inches larger in each dimension and which are held with screws." Quote Link to comment Share on other sites More sharing options...
ajsons Posted January 7, 2008 Share Posted January 7, 2008 The back panel is removable, so you can access the smaller covers, bottom left and right. Quote Link to comment Share on other sites More sharing options...
ajsons Posted January 7, 2008 Share Posted January 7, 2008 The crossovers are supposed to be inside the rear chamber. I'm not sure if this picture is trying to show the interior side of the access cover or if the builder chose to mount the crossovers outside. Quote Link to comment Share on other sites More sharing options...
HarryO Posted January 7, 2008 Share Posted January 7, 2008 The ones I just bought were very similar but not identical. They had the Jensen Imperial tag on the rear board. HOWEVER, the angled side boards actually had a porting system that butted up to the rear board. I wish I hadn't trashed the cabinets as I didn't pay a lot of attention to the detail. Harry Quote Link to comment Share on other sites More sharing options...
ajsons Posted January 7, 2008 Share Posted January 7, 2008 Years ago, I trashed a Karlson, and carelessly dropped the University 315 woofer and damaged the cone. Back then, I didn't know what it was worth.. Here's another page showing the access covers and crossovers.. Quote Link to comment Share on other sites More sharing options...
JDJohnson Posted January 8, 2008 Share Posted January 8, 2008 HarryO, You disassembled / trashed a factory built pair of Jensen Imperial cabinets that were in Very nice condition that you listened to for less than an hour? [:^)] I understand you bought them just for speaker resell and that you didn't like the way they sounded with those speakers anyway, but why not keep the cabinets and try some different drivers? Those would have been some fun cabinets to mess around with. Quote Link to comment Share on other sites More sharing options...
HarryO Posted January 8, 2008 Share Posted January 8, 2008 Guilty!!! I hate throwing a buck away but... 1: They sounded like crap 2: I didn't find the cabinets had any significant value 3: shipping alone was more than they could possibly be worth (assessed by the sound and size) 4: I just wasn't impressed with the cabinets at all. Maybe a poor decision on my part but it's the way I felt about them. Maybe lack of insight on my part but NOTHING about these did a thing for me. Harry Quote Link to comment Share on other sites More sharing options...
JDJohnson Posted January 8, 2008 Share Posted January 8, 2008 I understand. They sounded like crap to you. I thought the cabinets had value, but maybe not.They're big cabinets and it wasn't worth it to you to keep them around or try to mess with selling. I thought since they were factory built that they would be built solid. For me, it would have just been fun messing with those huge rear horn loaded cabinets to see what I could get them to do. I've thought about building some, but I'm satisfied with my Khorns. Don't feel bad about getting rid of them. I just wanted to give you a little hard time on it and you were a good sport about it. Thank you. I wish I still had my tube stuff from 1978 that I thought was outdated by SS, but we can't keep everything. Quote Link to comment Share on other sites More sharing options...
boom3 Posted January 8, 2008 Author Share Posted January 8, 2008 Harry, those might not have been factory builts. Here's a quote from "How to Build Loudspeaker Enclosures", page 101, describing the construction of the Imperial, also showing the plan that Boom3 had attached.. "While not shown in the sectional view, the access openings to the speaker and network compartments are covered with 3/4-inch plywood panels about 2 inches larger in each dimension and which are held with screws." Ahhh! That's it! I used to have that book myself...lost long ago.Thanks! Quote Link to comment Share on other sites More sharing options...
Q-Man Posted January 9, 2008 Share Posted January 9, 2008 I built a pair, because I read that this was one speaker that got it right. I loaded it with Klipschorn networks and drivers to compare it to the Klipschorn. 50 Hz and below it makes the Klipschorn sound like a book shelf speaker. It pounds you with clean bass, and it's cool how the bass also exits around the midrange and tweeter horns. I measured it with warble test tones and a Rat Shack sound level meter. I think it was about 6 db louder at 50 Hz on down to 25 or 30 Hz., where the Klipschorn doesn't even go. It could be a speaker to die for with a little tweaking. Someday I may get rid of my six Klipschorns and go Imperial. First, I would need to get one of the speakers to John Warren or someone close to me who is capable of measuring it, and figurings out the best 15" woofer to use in it. Maybe the K-33 is ok to use? I have to look it up, but the bass horn is good to 600 or 700 Hz. That means it would be easier to find a good midrange driver and horn for it. You could even go two way with this bass horn. Maybe I should bite the bullet and gat one to John. It is also easier to build then a Klipschorn. Quote Link to comment Share on other sites More sharing options...
Q-Man Posted January 9, 2008 Share Posted January 9, 2008 I use four speakers for my surrounds and one pair of Lascalas and the pair of Imperials. I like the Imperials there because they add bass to the back of the room. Really nise when listening to DVD-Audio and SACD's, since both formets send full range to all channels. Quote Link to comment Share on other sites More sharing options...
ajsons Posted January 9, 2008 Share Posted January 9, 2008 http://forums.klipsch.com/forums/p/156/2007.aspx#2007 it's a great thread, Q, but the pictures don't load. Quote Link to comment Share on other sites More sharing options...
JDJohnson Posted January 10, 2008 Share Posted January 10, 2008 Q-Man, I've read on the Internet that others who have compared the Imperials to Klipschorns agree with your findings. I've never heard a pair of Imperials myself, but sure would like to. Maybe I'll get lucky someday and come up on a pair. Love to hear a set of those Klipschorn Jubilee speakers too. For now my front Klipschorns and rear Chorus II plus two huge subs are keeping me in audio bliss. Like you, I like to be surrounded in sound. I don't run mine in surround mode effects though. Stereo front and rear. I've been hooked on two sets of speakers since I heard my brother's four AR11 speakers years ago. I still enjoy one stereo set, but for me a second set can sweeten it up a bit. My system is two stereo systems running off one source. Sometimes I'll just listen to the front stereo system and sometimes just the rear one, but mostly both at once and then wow... Nothing has to be run hard to fill the room so it sounds really good with very low distortion. I figured you'd understand me with the system you have. Do you have a photo of your Imperials next to a set of your Klipschorns you can post so I can see their size comparison? You feel the Imperials sound better than Klipschorns in all aspects? Quote Link to comment Share on other sites More sharing options...
turbobusa65 Posted January 15, 2008 Share Posted January 15, 2008 Anyone interested Imperials should have a look at Steve Decert's site "decware" he's even got improved plans to build the Imperials!! I built some folded sub cabinets from his site that are very impressive!! Quote Link to comment Share on other sites More sharing options...
John Warren Posted January 15, 2008 Share Posted January 15, 2008 The Imperial is a copy of the Milleniun 4-D by Stan White. The 4-D came with an optional dual 15" similar in appearance to the speaker shown in the decware website. The 4-D sounded very good and it was built rock solid. Quote Link to comment Share on other sites More sharing options...
John Warren Posted January 15, 2008 Share Posted January 15, 2008 Product brochure Quote Link to comment Share on other sites More sharing options...
John Warren Posted January 15, 2008 Share Posted January 15, 2008 another brochure, Note the theater system version 2x 15" drivers. The drivers were JBL. Quote Link to comment Share on other sites More sharing options...
John Warren Posted January 15, 2008 Share Posted January 15, 2008 Harvey Catalog page with 4-D Quote Link to comment Share on other sites More sharing options...
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