That's sort of a shame in both ways, because that series of Infinity car subwoofers was pretty good, it worked well in a small box.
Lee.
Speakers with questionable "upgrades"... post your findings here.
- Thread starter leesonic
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That's sort of a shame in both ways, because that series of Infinity car subwoofers was pretty good, it worked well in a small box.
Lee.
sum of sand
Active Member
colohiker
Well-Known Member
Actually, the rubber surrounds on the EPI woofers were glued to the top of the gaskets from the factory, the foam ones were glued to the metal frame. All the EPI rubber surrounds I have run into here in Colorado have been stiff and cracked with age.
sum of sand
Active Member
Oh seriously
Why? Ill research it
It peels right off the gasket and the surround is impeding travel
Maybe due to age
Looked like a refoam with the glue line lower than rubber
Why? Ill research it
It peels right off the gasket and the surround is impeding travel
Maybe due to age
Looked like a refoam with the glue line lower than rubber
Imprecise
Addicted Member
That bass port tube looks like it got broken (How?) and repaired. A bass reflex enclosure is carefully designed to embody a specific alignment. The mass of air in the port tube is a critical factor. Changing that even by a modest amount can easily screw up bass performance totally.
Imprecise
Addicted Member
To me, it looked like the bass port was in the way of the 'upgraded' woofer. The new woofer basket was too large to fit. So, the owner sawed off the port, to create wiggle room. Smart Guy!
Changing the woofer will screw up the bass reflex alignment as well if it does not have the same free air compliance as the original. The worst possible thing to do would be to put a woofer from an acoustic suspension system into a bass reflex enclosure. it would not work right at all.
I had some Realistic Nova 6 speakers as a teen. The woofers were crap and didn't last long--the bass output had both of the voice coils rubbing within a year. The tweeters were also paper cone and kind of dull sounding even when new (they were OK, but nothing great). I ended up upgrading a year or two later.
After having those cabinets sitting around for too many years getting in the way, I decided to put them to use. I had some Philips 6½" woofers on hand (from a long-aborted project) and a pair of mylar dome tweeters, and got to modifying it. I figured out the proper loading (this was back when we actually had to use a calculator to figure out T-S calculations) and put in a port. I made up some plywood rings to adapt the woofers to the 8 inch woofer openings. They actually sound pretty darned good, considering! They actually have a nice, clean sound to them now--less muddy in the bass, better mids. Since I didn't modify the grille to accommodate the port, I take it off when using the speakers. (It's better anyway--the plastic lattice work makes the sound kind of wonky.) I ditched the screws and put velcro on all four corners of the grilles. I used to play these outdoors all the time in nice weather, when I had a deck.
No pics for now--they're stored away in the basement.
After having those cabinets sitting around for too many years getting in the way, I decided to put them to use. I had some Philips 6½" woofers on hand (from a long-aborted project) and a pair of mylar dome tweeters, and got to modifying it. I figured out the proper loading (this was back when we actually had to use a calculator to figure out T-S calculations) and put in a port. I made up some plywood rings to adapt the woofers to the 8 inch woofer openings. They actually sound pretty darned good, considering! They actually have a nice, clean sound to them now--less muddy in the bass, better mids. Since I didn't modify the grille to accommodate the port, I take it off when using the speakers. (It's better anyway--the plastic lattice work makes the sound kind of wonky.) I ditched the screws and put velcro on all four corners of the grilles. I used to play these outdoors all the time in nice weather, when I had a deck.
No pics for now--they're stored away in the basement.
StimpyWan
Addicted Member
Imprecise
Addicted Member
Way back, Audio magazine would run articles from time to time providing programs for Texas Instruments scientific calculators to do things like enclosure design, crossover design etc.
I actually wrote one on a computer back in the mid 80s using BASIC.
I was even working on an improved version but never completed it. Those programmable calculators were cool back then, though! I have a more recent TI I used in one of the courses I took.
That sounds like a successful project and NOT a 'questionable' upgrade at all, so you're exempted from the derision inherent in this thread.
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Bassblaster
Super Member
i dont have any photos, but what about people that blow the woofers in tower speakers then run down to walmart and throw in a DUAL, Kicker or Pioneer car subwoofer in there.
EDIT: After actually reading this thread, im not the first to mention that.
EDIT: After actually reading this thread, im not the first to mention that.
swechsler
Frog Whisperer
It's worse when they do it just because the foam is shot. The second pair of Infinity Kappa 8s that I bought (cheap, luckily), one previous owner had replaced Infinity's excellent cast frame 12" woofers with a pair of Pyramid 12" (similar to the pic at the bottom of this post) disasters. Luckily I had a surplus of eBay bucks going bad, which allowed me to get a pair of the correct woofers essentially free.
Everything checked out great, one woofer was locked up but it’s a non issue. Those disasters are now no more, the parts will only be used for good honest reproduction, haha.
I actually wrote one on a computer back in the mid 80s using BASIC.
When I took EE4026- Acoustical Engineering (taught by Dr. Wm. Marshall Leach) at Georgia Tech- our final project was to do the calculations, to design a sixth-order band-pass enclosure, using, IIRC, an Electrovoice 12" driver (specifications provided by Dr. Leach). We were given both the driver specs and the desired lower and upper frequency limits, and had to calculate the enclosure volume and proper vent tuning
I kept making calculation errors (typos, mostly- my handwriting is terrible)- so I wound up writing it as a BASIC program, using the BASIC compiler in the HYDRA mainframe on campus, and later, the BASIC compiler on my new 386/Windows 3.1 laptop I had just gotten at the beginning of that term. This way, I only had to enter the formulas once, and once I got them debugged, I could do iterative analysis of the parameters, changing values to get the response to match the specified goals.
I mentioned to Dr. Leach that I had done this- but that I would write out everything at the end, so he could see what I had done, long-hand. He told me not to worry about doing that- just to submit the source code ready to compile on paper and on disk, and he would run it. I think he was pleased that I had made it such a general analysis (so that it was easy to enter in different woofers and bandwidth ranges- it became a usable tool for quickly designing enclosures, in essence).
I remember specifically, that he said that he didn't care what methodology you used to solve a problem, as long as it matched the first principles involved and gave the correct result consistently. I remember blanking out on the electrical-analog formula for calculating loudspeaker efficiency, on a test- and since I was an ME (mechanical engineering), I used thermodynamic equations to get the correct result. He actually gave me full credit- even though he had to look it up in a mechanical engineering book to verify I had done it correctly- saying that on the job, no one cares what analog you use- as long as it gives accurate results...
Rest in peace, Dr. Leach. I hope there's still professors that have that sort of dedication, inspiration, open mind and practicality, around now...
Regards,
Gordon.
Cool story Gordon. I bet you were one of his favorite students. Give a guy a problem and he solves it by creating a computer program. Maybe not so rare today, but I know how long ago you would have had a 386 and Win 3.1