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Vintage Asylum Classic gear from yesteryear; vintage audio standing the test of time. |
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Vintage Asylum Classic gear from yesteryear; vintage audio standing the test of time. |
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In Reply to: Larger Advents Revisited posted by mjcmt on September 21, 2014 at 10:01:48:
I've been through a lot of Advent experiments over the years. Your cabinets are obviously original walnut veneer cabinets with the original Masonite ring woofers. And the tweeters are certainly from the 4 digit series of Advents (5002, etc.)
I see two problems right off. First, the 5002 used a different, and higher order crossover than the original and New Advents; so it's unlikely you have a good match to the woofer which used a 1.6 mH inductor to roll off the woofer at 1 kHz. Even though the tweeter crossover is trying to roll off the tweeter at 1 kHz, it's properties are quite different than the original Advent tweeter; so there's bound to be peaks or dips. That original crossover also had a bypass capacitor and that boosted the highs - something that 5002 tweeter doesn't need. However, duplicating the 5002 crossover in its entirety should work.
Prolem #2 is the grill frame. It has a 3" diameter tweeter hole for use with the original Advent tweeter which stood forward of the front panel of the cabinet by about 5/8" and put the radiating elements of the tweeter right into that 3" hole. The 5002 tweeter is flush mounted and so energy radiated by the tweeter will hit the grill panel and the edges of the holes - that has to create issues with tweeter smoothness and the tweeters dispersion. I see two solutions to that. One is to remove the grill cloth and open up the 3" hole to 6" or more and then put a felt or foam ring around the tweeter just a but smaller than the hole size. I did that with my speakers when i installed New Advent tweeters and crossover. The other fix would be to cut a wooden plate to shim the tweeter forward so that the center dome is up into the 3" hole.
As far as the woofers go, the New Advent literature talks about a more robust design on the new steel frame woofer. I have tried both the new steel frame and original Masonite ring versions, and prefer the sound of the Masonite ring version in the midrange. They are supposed to be electrically and acoustically interchangeable and they are pretty darn close. The mounting hole pattern is the same for both; but the original needs a larger hole in the panel - so a steel frame will mount in an original cabinet; but the Masonite ring won't go into a New Advent cabinet unless you do a little carpentry. Long after the 4 digit Advents were gone and Jensen owned the name, Jensen brought out a Classic (AKA 25th anniversary) speaker with New Advent looking cabinets and steel frame woofers and a dome tweeter. I have a pair of those woofers, and Jensen really got it right as they sound exactly like the New Advent woofer.
The Advent grill cloth was an open weave linen; which has very little sound absorption. I tried several alternatives, and eventually wound up using either a fine textured burlap from a fabric store, or the black stretch grill cloth from Parts Express. The original Advent used a black gauzy material (something like book muslin) under the tan linen. It is a part of the acoustical design with the original Advent tweeter. So when using the original tweeter, I always made sure there was a swatch of the black gauze behind the grill cloth over that 3" tweeter hole. Yes, you can hear and measure the difference. With the smoother New Advent tweeter, or the 5002 tweeter, you don't need that underlayer.
I looked up your references about the crossover. That's the wrong crossover for that tweeter. Look at the schematic for the 5012 crossover from Basel. That's what you need, as it is a third order electrical on the tweeter, and first order electrical on the woofer which probably comes out as a third order acoustical given the woofer rolloff characteristics.
Jerry
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Follow Ups
- RE: Larger Advents Revisited - Bold Eagle 10:53:12 09/22/14 (1)
- RE: Larger Advents Revisited - mjcmt 11:08:14 09/22/14 (0)
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