I asked some questions earlier this year about how the UREI 813 elements and their time aligned crossovers would fit in the Imperials and I got an answer from the master himself that it would fit. I have now tonight connected the first speaker of the pair to my HIFI and it is amazing... I built a pair of speakers two years ago based on a Swedish bass reflex patent that was adjusted to match the Altec Lansing 604 8K. They sound very good but now with the Imperial standing beside them they are not only midgets in size but also in sound reproduction. However there is some flaws in the design that I bought and downloaded. The braces A should be at least 130 cm to be flush to the bottom reflecting plate and you should also be careful with the gap from the compression chamber. Minor issues but anyway the sound is amazing. Through my years I have owned a variety of speakers ranging from Magneplanar Tympani and downwards but the old Altec Lansing 604 8G koaxial with the Eminence 15" bass speaker from the old UREI 813 takes the price.    

I have now the second Imperial up and running. Unfortunately was one of the 604 8G and one of the Eminence 15" bass speaker damaged at Johannesburg intl ground handling. I managed to repair the 604 8G but not the bass speaker. Instead I bought a pair of P-Audio C15 500LF 500 Watt bass speakers. They have a FS of 39Hz, VAS 155 liters, QTS 0.29.
The other Eminence is ok but they are not designed for this speaker. I have tested the speakers both with Altec Lansing 604 8K and the UREI modified 604 8G and they work perfect. Together with the new bass speakers they are amazing. I have had several friends visiting wishing that they were not married due to the size of the speakers.

Here is a new picture of the pair. The will be coated with Epoxi and then sprayed with black Gel Coat.

I am presently living in South Africa and visited Sweden last week and found a set of Altec Lansing 811B horns and 908 8B drivers. They sound much better than the JBL 2412H drivers. I have finally sent the Imperials to the paint shop and will publish a picture when they are done. I also found a pair of Mantaray MR94 horns with Altec 288 8G drivers in mint condition. They are huge and they have to wait in Sweden until I move back. It now seems that journey of building and equipping the Imperials pretty much has come to an end.

I just got the Imperials back from the paintshop. The work is not 100% but this is Africa. However they sound very good now with the Altec 908 8B drivers connected to the 811B horns on top.

Yes, that`s the present configuration. All 6 speakers driven through a dbx Driverack 260. The MR94 horns will be a part of the setup when the Imperials have sailed back to Sweden.

Hi Everyone!
I'm impressed by these imperials and am thinking of making one myself. How does one compare to a ported design or a bass-reflex?
Regards,

I have been building my new house for 6 month now. It is nearly finished.
I decided in april that if I have built a pair of modified Imperials, why not continue with a pair of bigger horns? The picture shows the final stages before they were covered. There is now a 6.1 meter long and 0.6 meter horn mouth in the living room floor. I am using 4 pcs  Eighteensound 15" 15W200 woofers. They will give 124db at 20hz. I will cut them at approx 40hz. The imperials will do the rest. I will come back with a report when everything is up and running. I have been involved in modifications of a new 8 channel DSP cross over. The end result turned out to be very good. I will now start distributing them.  

Hi Azul.

Are you still contemplating to build a pair of Decware Imperials? I have listened to some 30- 100.000 USD speakers since I came back to Sweden. They all look very good and they use materials as kapton and beryllium and perhaps kryptonite, but do they sound better? I say no..
Physics has not changed since Altec Lansing started to build their 604 speakers during WW2. Klangfilm was designed at the same time and still sounds extremely good. I am a firm beliver that if you in your approach to music like to be "there" 30-100 feet from the jazz group or the philarmonic orchestra, -High Sensitivety, Active Crossovers and proper horns will make your day. This Saturday I will marry a woman that understands what it takes to go under 50hz.
Good luck..

If you take all costs in consideration, the Decware Imperials does not come cheap. You can easily end up between 5-10.000 USD for a pair.
If you look in Jensen`s technical bulletin from 1952, they are there in the original with one 15" woofer.I am using them as a 2 way system now dividing at 800hz. You can divide the Altec 288 8G compression drivers with MR94 horns as low as 500hz.
The HIFI world is a very special world and defined by belief like religion. My simple belief is that if you like to reproduce a sound as close as possible to a "live" situation where you physically can feel the music, you need to go with speakers with high sensitivity and horns. If you sit on row 15 in Berwaldhallen and listen to Anton Bruckners second symphony, you feel it.
I decided that if I am going to spend over 6000USD in parts and material for a pair of speakers, it would be stupid to go with passive crossovers as I would have to rebuild them for my new living room not knowing of coming reflexes and resonance frequencies. Another reason to go active was to avoid the cable jungle. As differences in capacitans and impedance allways excists between components, cables function as equalizers giving your speakers different sound reproduction. I avoid most of this by using a good quality DSP loadspeaker management system.
I can not judge if your speaker elements are better or worse but I do know that if you buy proper elements for the Imperial you will be rewarded.

Here is a link to homepage where the Decware Imperial is simulated.
http://www.linnaraudio.com/simuleringar/imperial/index.htm
Have a look.

Wow, wait a minute, 5000usd? where did you come up with that number? I calculated 1200 sfr for the wood, roughly 1500 for the cabinet, with the two daytons it shouldnt exceed 2000. Did I miss something or are you simply using high end drivers? regards,

I built my imperial for between $500 and $750 USD to Decware specs. It sounds great and have used it both as a sub and full range with a 1" horn on top. As a sub I was shaking an entire theater of about 750 seats. Made the glass on the back wall rattle.

Building the Decware Imperials has made me change my HIFI attitude totally and the following would never have happened if I had not found the Decware Imperials on a HIFI forum in 2008.
In late 2008 I bought a dbx Driverack 260, a Rotel RMB1077 7 channel class D amp and started to drive each speaker element separately. Last year I tested several of the high end active crossovers with price tags up to several thousand dollars when I stumbled upon the Bunker BPD-1. I started to talk with the manufacturer and eventually we initiated a cooperation. This has resulted in a HIFI version with a linear power supply that sounds outstanding. My Imperials are now digging down to 20hz and they produce an improved more transparent high end.
I am now the distributor for Europe and Africa and we are presently building a homepage that will be devoted to active amplification. I our demo facility affordable open baffle and horn speaker solutions will be used as references and the most important reference are my DECWARE IMPERIAL`s. Have a look at www.taot.n.nu    

I have now after 5 years replaced my DSP Bunker BPD-1 with a dbx Driverack Venu 360. This new DSP sound good and is a step forward. My Decware Imperial speakers are still the best investment in time and money that I have done for my HIFI. They make a nice combo with the Mantaray 94 horns and the old Altec Lansing 288-8G drivers.

Hi, sorry for late reply. The room is 81sqm.

Hi, if you have a big room then you can`t really hear them. Smooth. I now drive them with a pair of Altec 299 16ohm.