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Though my experience with horns in the past has been a miserable one it didn't dull my interest in them. In the past, at two hifi shows in Melbourne, I thought all the commercial horn based speakers I've heard, JBLs included weren't very good. And in a few domestic situations things didn't get any better.
Looking at Altecs on eBay they are usually pretty knocked around, being a speaker from the late 70s. They are about US$500 a pair with dubious compression drivers. It gets worse; shipping the buggers is usually about $100. But I was always open to any which may come along.
And along they did. In a nieighbouring state a pair of fully refurbished powder coated Altec 511Bs popped up at a reasonable price. Two bonus facts are the owner would share shipping ($40) and the were dodgy compression driver free. The drive will decide the sound and in the past all metal diaphragm drivers have sounded just wrong.
Welcome the Italin Faital Pro HF108R and their polymer based diaphragm and neodymium magnet driver. Fortunately there is a DJ store 30mins easy drive from me which sell a few different drivers. I bought their dearest hoping for the best sound possible. Bonus, they gave me slight discount. It's all up from here.
While waiting for the horns to arrive I modded a very good Xover to deliver -12db roll off for the woofer and -18db (2nd and 3rd order) for the horn. Xover point is 1600hz. The driver goes down to 1KhZ and will handle 60W! Some drivers will go down to 500 but to me a 1" metal diaphragm going 500hz seems just wrong. Also the HF108 is 106db effciency so a -17db pad was required. I had many pads from another two way system which I could use (and now have tweaked) to give about that suppression.
I had everything all setup and ready to go and within 30mins or so had the Altec 511Bs (designed to work down to 500hZ) up and going. This included fitting the new compression drivers which came with gaskets fitted and mounting bolts.
So Mark how do they sound. In a word "fabulous". Firstly the horns are pristine 100% condition and better than new with a thick, dense black powder coat. No dints or bits missing. I had about three hours of listening yesterday and played about 6 different genres of music and loved everything I heard. The horns sit on subby boxes I have had for some time which have a 12" poly cone with a fo of 25hZ tested. The trick is to not roll the horns in too early so voice bass etc is carried by the woofers. The woofers go down to 30hZ tested and are good to 4KhZ but nicely start to roll off at 2K. Rolling them off and into the horns at 1600hZ is just a perfect Xover point.
There is stacks of deep bass and the woofers are 92db efficient so now the system is 92db efficient. My 2W SE UL 6L6 power amp in combination with my new 4S preamp play plenty loud and a really sound good. Listening to test tones the system is good down to 40hZ with some output at 30hZ. I'm a happy man.
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