Jensen Imperial plans
Printed From: Speakerplans.com
Category: Plans
Forum Name: Scoops
Forum Description: One scoop or two ;-)
URL: https://forum.speakerplans.com/forum_posts.asp?TID=50914
Printed Date: 26 March 2026 at 9:59pm
Software Version: Web Wiz Forums 12.08 - https://www.webwizforums.com
Topic: Jensen Imperial plans
Posted By: Lee In Montreal
Subject: Jensen Imperial plans
Date Posted: 10 April 2011 at 5:53pm
The Jensen Imperial cabinet was the model on which Richard Long based his 4520-looking Waldorf. The GSA'S Waldorf is using the same plans as RLA's after Long's death. |
Replies:
Posted By: TDA-Audio
Date Posted: 10 April 2011 at 6:40pm
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\\\\\The GSA'S Waldorf is using the same plans as RLA's after Long's death.\\\\\ wery good sound from GSA scoop!!! yes -simple imperial still ------------- horns plans http://photofile.ru/users/tda-audio/ |
Posted By: Lee In Montreal
Date Posted: 10 April 2011 at 7:38pm
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Actually the Jensen design makes way more sense than the 4520-4530 layouts. The JBL designs have two 180° bends which cause massive havoc within the cabinets. While the Jensen design has only one 90° bend, which I am sure can be smoothed out as a nice curve, reducing problems. The Jensen design is such a simple idea. Also, in the Waldorf, one driver is used from 80Hz down, and the second driver isued 50Hz down for a strong thump. |
Posted By: JR.junior
Date Posted: 10 April 2011 at 9:13pm
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jensen imperial quad design.  ------------- Support the scoop technology, larger mouth plays louder! |
Posted By: subbass
Date Posted: 10 April 2011 at 10:27pm
| woooooooooooooowowoo |
Posted By: Lee In Montreal
Date Posted: 10 April 2011 at 10:32pm
I think this would be an earlier generation of the Jensen Imperial.  And looking at the RLA design as produced by GSA, it seems the later design was retained for twin drivers. Look at the port on the ceiling. I wonder if the empty volume was used. Less compression (slower bass) but deeper bass would be the gain.  |
Posted By: rich, ind.st
Date Posted: 11 April 2011 at 12:34pm
------------- music is god |
Posted By: TDA-Audio
Date Posted: 11 April 2011 at 6:57pm
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\\\\Look at the port on the ceiling.\\\\ cut for magnet (deep fraime driver) ------------- horns plans http://photofile.ru/users/tda-audio/ |
Posted By: rich, ind.st
Date Posted: 11 April 2011 at 9:47pm
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back to the oldschool <grin> http://img848.imageshack.us/i/06042011142.jpg/ - http://img848.imageshack.us/i/06042011142.jpg/ only got two of em loaded up to test so far (so effectively 1 standard imperial as we've cut 'em in half)... the adage of 'if it aint broken, don't fix it' is ringing very true. ------------- music is god |
Posted By: Lee In Montreal
Date Posted: 03 May 2011 at 2:03am
This copy of Jensen Imperial used to be in Jamaica, belonging to King Tubby, most likely not in his studio, but in his "Sound Systems". It was auctioned off on Ebay a couple of months ago. Those who are into reggae and dub most likely understand who King Tubby was... The others, keep on playing MP3s... ;-)  |
Posted By: pfly
Date Posted: 03 May 2011 at 10:17am
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Although I love what King Tubby did, I can't stop wondering about the horn profile with that scoop. Seems like it is really really narrow right until the last fold, where horn expands rapidly. I guess that thing is tuned reaaaallly low... |
Posted By: rich, ind.st
Date Posted: 03 May 2011 at 12:06pm
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I have just built 6 half imperials, whilst they play low they produce a fairly even and balanced sound between 30 and 500 hz. The phase dip is much much less pronounced than on modern scoop designs, i'd argue it acts more like an average size reflex box with a huge flared port than a modern small chamber long horn type design. I've wanted to build some of these for years which is strange considering my general dislike of scoops and the typical scoop sound. My view is that modern scoops have been fixed and fixed and fixed by a number of people since the early days of king tubby using them. sometimes you have to build something to find out if the original was broken in the first place. http://img706.imageshack.us/i/28042011175.jpg/">  Uploaded with http://imageshack.us - ImageShack.us Had them out for their inaugural outing on friday at a night playing a variety of hardcore/gabba/hardtek type stuff and they certainly didn't dissapoint. very bangy but also hitting the low notes when required. we were crossing them to the hornloaded 8's at around 500hz. have also tried them in 'classic oldschool reggae system mode' i.e. fullrange with a piezo on'th top and even that sounded fairly acceptable ;) ------------- music is god |
Posted By: opus jody
Date Posted: 03 May 2011 at 8:44pm
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And very tidy they sounded too. Good build.  ------------- Improvised Hardware Music http://vimeo.com/user9389813/videos |
Posted By: junglemonkey
Date Posted: 17 May 2011 at 11:14pm
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hi rich,
those half imperials look sweet!!!
how are they to transport can't quite get the scale??
and what have you loaded them with?? ------------- without good foundation you have nothing!! |
Posted By: Lee In Montreal
Date Posted: 25 December 2011 at 2:12pm
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Found this interesting sequence of pictures depicting the build of a single driver Waldorf by Shorty. Fun starts at picture #69. It answers a few questions I had about angles and sequence of assembly http://www.myspace.com/soundmanshorty/photos/43255154 |
Posted By: S&P
Date Posted: 09 October 2014 at 11:06am
I understand that this box doesn't have any guts. Basically it's a reflex with a big flared port. I've heard it in action once at Brixton Hootenanny - it was being run alongside other boxes, powered by valve amps. It sounded good as far as I could tell, but started flapping a bit when driven hard. Might have been valve amp distortion rather than the box possibly. To be fair it was a lot of room to fill with a 15"!! ------------- Sounds and Pressure Lo Fi Sound - Ska, Rocksteady, Reggae http://www.facebook.com/events/412323448834558/432237103509859/?comment_id=432362186830684¬if_t=event_mall_reply#!/groups/75371249167/ |
Lee In Montreal wrote:Posted By: Rico
Date Posted: 09 October 2014 at 1:16pm
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Can anyone recommend me a good 15" Driver for a Jensen imnperial horn?, i know jensen still build vintage Drivers, but they are for guitar Speakers, so i doubt they will Sound good.. Thanks
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Posted By: T-Bone
Date Posted: 09 October 2014 at 3:04pm
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Lee I've been reluctant to build the Imperials I have the plans but as an option Steve says depends on your application Bass to Mid bass a good 15" woofer for bass duties with high Qts and long Xmax no higher xover than 75-80 Hz. But was thinking using this upper bass to mid kick like 75-300 Hz been thinking of the 18Sound 15MB700 for this. Look Rico also the website inslow sound he's got a 21" version mod incredibly low bass I saw a year ago on the web. I have PD2150's I may build Imperial 21's or MTH 4654 from Marc. ------------- BASS, how low can you go! |
Posted By: Rico
Date Posted: 09 October 2014 at 3:21pm
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Whats High QTS in your opinion, the Jensen Ceramic Speakers got a really high QTS http://www.jensentone.com/vintage_ceramic/c15k" rel="nofollow - http://www.jensentone.com/vintage_ceramic/c15k But i doubt they Play really low, and the Xmax is not realle Long with them.. Regards
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Posted By: Lee In Montreal
Date Posted: 09 October 2014 at 4:27pm
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I would use a driver with the lowest possible Qts for a horn loaded bass cabinet. 0.2 to 0.25 at most. Lee |
Posted By: JR.junior
Date Posted: 09 October 2014 at 4:39pm
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+1 ------------- Support the scoop technology, larger mouth plays louder! |
Posted By: Rico
Date Posted: 10 October 2014 at 10:22am
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Ah yes for shure, how could i forgott it, a low Qts is necessary not a high ;-) But, whats strange, there are alot of Scoops with Drivers over 0.3 QTS Fane colossus XB 0.3.. Some are using Volt Driver, wich also got about 0.33 im shure there are plenty more around. Whats the Problem if its too high? regards
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Posted By: JR.junior
Date Posted: 10 October 2014 at 10:38am
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the motor has less control over the cone. ------------- Support the scoop technology, larger mouth plays louder! |