Recycling old designs ???


Several different factors have caused me to start this thread. I'm begining to wonder if we have made ANY progress in audio gear over the last 25 or so years. While that is kind of a rhetorical question ( obviously, we have ), i've run across a whole slew of interesting "already been done" designs recently. On top of that, i also noticed that we had DIGITAL amplifiers as far back as 1975. Has anything REALLY changed ???

How many of you have seen the "new" Mirage "omnipolar" speakers ? They are shown on the inside cover of "Sound & Vision" mag in this months edition. As soon as i saw them, i had to laugh.

The reason that i found them funny is that they are a COMPLETE knock off of what B.I.C. did with their "Soundspan" models TWENTY+ years ago. Only difference is that the Mirages are smaller, wall mountable units whereas the BIC's were all boxed models designed for floor standing use.

Some of you may remember these. They looked VERY much like a set of the old Ohm F's with their grill's on. The similarity did not end there though, as they were trying to mimic the radiation pattern of the F also. The major difference is that they used a three way design to do this whereas the F is a single driver ( point source ) as the radiator.

How the old BIC's and Mirage do this is pretty simple. They place a woofer on the top of a box / speaker cabinet firing straight up. They then suspend the midrange directly above the center of it, kind of like a coaxial design found in many car audio speakers*. This forces the sound from the woofer to "slide out" sideways around the back of the radiused midrange "cabinet", increasing horizontal dispersion. This same approach is used on top of the midrange with the mounting of the tweeter. All speakers are firing directly up but reflecting sideways due to the placement of the driver above it with only the tweeter firing into free space.

What this does is produce 360* of horizontal radiation. The effects of beaming are minimized due to the fact that you have no direct sound radiating towards you. While this does give you a very spacious and diffuse presentation, it can also lack "crispness" or "attack" since all of the sound is heard indirectly. Simply for sake of comparison, the F achieves 360* horizontal radiation BUT also exposes the listener to direct radiation at the same time.

I would think that this approach would work wonderfully for use in a multi-channel HT environment, especially as surrounds. My Brother has told me a million times that i should use the four Ohm F's that i have as mains and surrounds in my HT system for this very reason. Lo and behold, Mirage comes out with this line and it will probably be a success for the "all enveloping" radiation pattern that could literally "surround you in sound". Believe me, it could do this IF done properly.

The question is, was it a design that was WAY ahead of its' time back in the late 1970's or did it need 20+ years worth of refining to make it "right" ??? Is this a product design that lends itself to only HT systems or will it find its' way into audiophile grade 2 channel systems ? Only time will tell.

How many of you have seen products or designs that were "recycled" lately ? It might be interesting to see if we are running around in a big circle and don't even realize it. I'll post some of my other findings later tonight. In the meantime, i hope to see that others have contributed to this thread. I think it will be fun to walk down memory lane and then compare those products to what we have today. Sean
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* Tannoy and a few other manufacturers also make use of coaxial mounted drivers, but for reasons other than what is being discussed here.
sean

Showing 1 response by jvia

I don't know if you would call it "recycling" old designs as much as I hope taking a new approach to old designs. I really don't think too many should be surprised by some of these design ideas resurgences. You talk about it from the 70's, I had a pair of Stu Hegemanns transmission line enclosures from the 60's just a while back, tweeter mounted coaxially and both woofer and tweeter firing upward, into an aluminum dispersion cone, same basic priciple. We all know tubes are incredibly popular, and vinyl is definitely stronger than it was 20 years ago. Some of it plays to nostalgia, some of it plays to people remembering a design and thinking that with new materials and advances in known sciences that these ideas are due another visit, perhaps working better with these new materials and ideas. I have a current fascination with transmission line enclosures, having just traded for a pair of IMF RSPM's,(the 1st pair of Ohm's were traded Sean) hooked up to an D76a I think its an incredible sounding system. Now I want to upgrade the xver, tighten up the response, change enclosure damping materials, etc. Why would Mirage not be having the same thoughts? At least I hope that s why they are doing it, not for the sake of the ad writers having to have something new to talk about.