I'm deep-sixing the glass packs on my Ford. I have exhaust out to the bumper but conversation while driving is difficult, can't hear myself fart either. Raspy.. has that blattttt sound so they have got to go. Picked up a pair of Dynomax oval mufflers, 20" long and I'm gathering the rest of the parts to do the swap. I had Cherry Bombs on a few cars, but these are too loud. I think it was quieter with straight pipes.
The "glass" in glass packs is there specifically to attenuate high frequencies, it is basically transparent to lower frequencies. (Lower meaning less than around 400hz if I remember correctly?). I don't know what "turbo mufflers" are but noise canceling happens at a specific frequency (actually a narrow band of frequencies) based on the geometry of the muffler internals. The fun part is anything you do to cancel one frequency will boost another so it's a game of moving energy around. Not to nitpick but 'glass doesn't really cancel a sound, it attentuates it over a much wider frequency range than a cancelling device (ie Helmholtz chamber) might. Smaller tube diameters attenuate lower frequencies so in general lower tones come from larger pipes and fiberglass somewhere in the system. Mufflers have sweet spots. Put a muffler in the right spot and it could kill an exhaust drone. Put the exact same muffler in a different spot, and it may do nothing to the drone. It can get so sensitive as flipping a muffler end for end will make a noticable difference. Trivial fact: Back in the day of the Jeep Cherokee (XJ) and Commanche (MJ?) - they used the same muffler but it was flipped over on the MJ to compensate for the different length tailpipe. So basically when people talk about using certain mufflers, the results are in general terms. That's why Ricky Racer might have had fantastic results with the Zoombang 3000 on his car, but when Goldchain Charley tried it on his it sounded like crap. There are general rules but the details vary.
I'm starting to believe that the exhaust tube itself may contribute to the noise. If it is thin, it will inherently transmit noise through it.
The OP stated "Here's the problem though, I can't drive it to work because I leave at 5:30am and the garage is right by the kids bedroom." It's a matter of comparison- between a "glass packed" muffler and a "Turbo" muffler. It is meant to be taken in general terms- not absolute. A "Turbo" style muffler is different from a conventional chambered muffler. I believe that it is based upon the mufflers originally developed for the Corvair Monza turbo- hence, the moniker. Feel free to research it further if you would like.
get a set of cutouts like JC whitney used to sell. they had a choke where to open and close them. route them through a single quiet muffler when needed and run them open the remainder of the time.
Hung Magnaflows under the O/T car we just finished. Idle, low speeds, a sweet sound of power, almost quiet, no real drone. WFO, awesome sound, nothing like the tin can sound of Flowmasters or Holley/Hooker knock-offs. I like em enough they'll go under the GTO. That's assuming I live long enough to finish it...(!)
The Jalopy Journal
