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In the Forum: Horn-Loaded Speakers
In the Thread: Rare Onkyo HM-300 MK2 Horn...need info
Post Subject: Onkyo Scepter 500 and othersPosted by derik736 on: 2/25/2018
So, two almost two years later and this contraption is still in my room and "ain´t goin nowhere" :-)
Guys, I became obsessed with horn speakers and specially with Onkyo product so I would like to share with you my latest experiences.
The speakers I talked about still stand in my listening room and turned out to be probably the best speakers I ever had. I don´t use the TAD tl1601 anymore, I bought mint Altec 416-8a with all original cones and coils. I damped the 828 enclosures and reduced the area of the reflex port to 75 square inches, than to 50 inches. Thast gave me THE BEST bass and midbass I have experienced in my system EVER. I mean the Altec 828 and 416-8a play easily to 30hz now and even a bit lower. Probably some of you will say that these enclosures weren´t build for that kind of bass reproduction but I sware they just kick ass. I don´t use my subwoofers anymore except for home theater. I was absolutely mesmerised the first time I have pluged the 416 into my system. The vocal reproduction in uncanny, none, absolutely none speaker I listened to was capable to reproduce the voices in such intimate manner as the VOTT. I was completely shocked. I sold my Tannoy Monitor Gold 15 and decided to buy Altec midrange horns, crossovers and drivers. Since 416 was so good, the rest must be equally good or even better right? I got the 808a with symbiotic diaphragmas and 511 horns. What a dissapointement. This horns comapred to Onkyo Hm300a literally look and sound like crap. The 511 horns are build from thin metal shit and ring like a bell. Onkyo is completely from cast iron. It weigt 15Kg and is much more neutral than altec which sounded edgy and sharp. I know the 808a isn´t the best Altec driver but it wasn´t even the same league as the Onkyo.
Let me tell you something about the hm300a. These horns/drivers are made in Japan in 1972 or so. This was the japanese answer for JBL, ALtec and other western brands that were very popular in Japan in 1970s. Onkyo called their flagship top of the line speakers "The Scepter". The produced a ton of different drivers and horns, all of them with spectacular quality. How do I know that you will ask. Well, I have a ton of them. I bought Onkyo drivers like crazy for last two years 
the first series with alnico magnest like HM300a, HM450a, HM500 and tweeters like tw1500, tw7a, tw8s. Some of them I sold, other I kept.
One day I bought something very spectacular, a pair of later built d5020a drivers, not alnico and much newer than the old hm300a.
The d5020a are from 1978 and were a smaller brother of the d6540a drivers which were the midrange drivers of the most expensive speakers Onkyo ever built.
Ladies and gentlemen, meet hte Onkyo Scepter 500:
http://audio-database.com/ONKYO/speaker/scepter500-e.html
Would you believe Onkyo ever built such high end speakers? And now they mostly build some medicore surround receivers 
Anyway, these monster horns were about 600000 yen each, it was a fortune in 1978. And I became obsessed with them.
It is a 4 way system with 15" bass driver in bass reflex enclosure, 1.5" midrange driver, one tweeter and one super tweeter. By accident I bought the d3520a tweeters first and tw3001 super tweeters shortly after that. But the other parts were missing. I thought it would be impossible to find the rest but thankfully I was wrong About two weeks ago a friend of my from Germany offered me a complete Scepter 500 speakers without enclosures. I mean EVERYTHING. I only miss the NT4a crossovers but I got very similar NT84a 4 way crossovers. He also sold me a lot of different Scepter parts like different drivers, horns and acoustical lenses.
I will post some pictures within next few days as soon as I´m going to get rid of that flu that keeps me in bed since 3 days.
I want to build a pair of Scepter 500 clones, a little bit modified and I hope you can help me a little bit with this project.
See you soon
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