I cannot find a thread that speaks of switching a Polycell tweet with an EMIT.
Does any one know the do's and don'ts, Pros and Cons. Crossover problems?
I see a lot of SM115's, SM150's for sale but I am worried about them being clear at the top? Not that worried about changing hole size......Thanks

I've never seen this article either, but am now interested too.

I find the Polycell nice, and like it, but it might be best described as polite.

Hoping it pops up...

The D : Yes I figured I would get a hole bunch of information flying around about this one. It must not be worth putting up with later day mids and woofers to think about it. But even for DIY like me that plans on doing a bit of work on infinity's it should be something to consider. Must be a dumb question as I am sure it has been discussed and thought of. Did a half hour search and could not find anything. Come on guys.......Explainations to us explainatoids are in order.

I know that this series Infinity doesn't get the respect as other Infinitys, but nonetheless I find 'em a good speaker, plenty of healthy bass, decent midrange, good and polite (but not fabulous) highs.

I know my Reference Threes still sell well- $100 to $150 average. So they haqve their fans. I've got mine with factory stands.

you might want to compare freq. crossover numbers for speakers with the with the same size drivers and polycell as opposed to the ones with emit tweeters in them you would like them to be close for the best sound

This might make for an interesting DIY project. The only thing I can think of other than changing the cabinet to fit (which you mention) would be that most if not all emits are 4Ω You probably will need to change your crossover because the SM series is an 8Ω speaker. Check the values of the poly tweeter and go from there, if its 4Ω you are good to go. If not then you've got some changes to make.

The difference in efficiencies were the forst thing that came to my mind. You'll probablyt have to pad the rest of the system (mid & woofer) to bring it down to the EMIT.

for what it's worth, my Reference Threes are 6 ohm speakers, if that makes any difference.

they use the Polycell.

I much prefer the EMIT over the Polycell.

I have RS-5s in my home system . . .

Fred Longworth

Hmmm... I would think you'd need to know a lot about the response curve of the two drivers, and their absolute phase, before you could redesign the crossovers to work correctly.

Example: if the Polycell rolls off its response at 4db/octave while the EMIT rolls off at 8 db/octave, you'll create a dip in the system response curve where the tweeter hands off to the midrange driver.

Or so I foolishly believe... :D

I really like the Polycells in my RS-9s. They do a great job. But I really like my RSbs with EMITs too.

If you're thinking about the Infinity SM series I'd seriously wait for other models from 1976 on. They took a "Quantum" leap in quality and sound.

http://www.infinity-classics.de/infinity/models/index-models.htm

Oh and welcome to AK.

Cheers

I grafted emits onto Dahlquist DQ 10s once. Lots of crossover fooling around was needed. They were much more efficient than the DQ dome+piezo, so the I suspect the crossover would need a lot of alteration. Emits tend to be flat :)), and most domes have a treble peak, so any crossover coils in parallel with the polycell would have to be removed.