Repairing 27 year old home audio speakers

While in my workshop a couple of months ago and realized that my vintage audio system’s output was really weak. No bass from the subwoofer and sound from only one speaker. The speakers were Baby Advent IIs that I bought in the early 90’s.

For you young pups, before satellites and Bluetooth speakers of today, having decent audio in the home required buying components and speakers from an HiFi dealer like HiFi Buys, Circuit City, or Crazy Eddie, to name a few. The populer speaker manufacturers of the day were Polk, Bose, AR, JBL, Altec Lansing, and Advent. Jensen was a popular vehicle sound component builder, especially speakers. You don’t know how good you have it now, not to have to hacksaw two holes in your car’s rear seat shelf in order to mount Jensen 6x9 coax speakers, then pull up the carpet to run wires from your under dash mounted 8 track. :smile:

Advent made a name by building quality two way speakers for a reasonable price. Audiophiles liked them for their flat “reference” sound in order to critique equipment and albums. They tended to use heavy wood and smaller drivers than their counterparts, preferring not to color the sound with heavy bass or a midrange driver. However, the high cost of manufacturer in a competitive market meant that they eventually were sold. Jensen bought them and immediately began using cheaper components, such as particle instead of real wood. Initially, buyers didn’t mind because while finish was not as good, they used original Advent drivers. So the sound was acceptable. Eventually, Jensen began using their own manufactured drivers and the sound suffered. I’m not sure what components are in the Baby II’s. I know that reviews were good, albeit they had a reputation for fragile tweeters. More on that later.

Removing the front panel of one of my speakers, I was surprised to find multiple holes in the foam surround that attaches the outer edge of the cone to the speaker frame. Pushing lightly on foam with my fingertip, caused it to crumble into a black gooey mess. Quickly, the outer edge of the became completely disconnected from the frame. The speaker that was working also had a couple of holes beginning to appear. The subwoofer was in the worst shape even though it was about 5 years younger than the Baby IIs.

I thought about throwing them in the trash pile, replacing the drivers as I have done with some of my guitar amp speakers, or just bringing a Bluetooth speaker down to the shop. But these have sentimental value in that they are one of my few remaining reminders of bachelorhood. Replacement 6.5 and 8" drivers would be not expensive, but what to buy. While researching I discovered not only a speaker repair YouTube video, but how to repair the Baby II. The foam replacement kits were cheap at less than $25. I found the subwoofer kit at Simply Speakers for the Polk 8" driver that would work well for the Advent subwoofer.

I replaced the Baby Advent’s foam surrounds using the video as a reference, then a few weekends later tackled the subwoofer. I won’t go through the whole process step-by-step, because the video linked above does a much better job of that than I could.

A repaired Baby II. Note that I prefer quantity over quality when applying adhesive. Concerning the “fragile tweeters”, see the cracks near the screws holes? Initially I thought that meant that the drivers would fail. I haven’t touched them.

The subwoofer cone after scraping off the residual foam from both the speaker frame and edge of the cone with an Xacto knife and a little alcohol.

Trying out the replacement foam before gluing.

The subwoofer driver date code 220 means Advent, but the rest is jiberish compared to there traditional coding. A date label on the cabinet states Sept 11, 1997, or 4 years to the day before the final attack on the Twin Towers. The magnet and my heart is heavy.

While working on the driver, I decided to replace the rubber adhesive-backed feet with something a little more permanent. Found some old amp cabinet feet in my guitar toolbox.

I’ve read that amp outputs more than 200 Watts RMS, but it sure doesn’t look that way. This is not the hand wired point-to-point build of earlier Advents. Gets the job done though.

Control panel. To my ears, with the Babies, a cutover of about 120 Hz is pretty good. However at the low levels that I usually listen to them while in the shop, the subwoofer is for nostalgic purposes only.

Repaired subwoofer.

Ready for a sound check.

Baby II back panel.

The results with some era appropriate source material. RIP Mark Hollis.


That’s so cool! One interesting thing you mentioned that caught my attention was JBL being a big name back in the day.

We currently have 2 blue tooth speakers made by JBL (mines smaller but it’s in camo!) and the sound quality is fantastic out of both of them. I had never heard of the brand before these and bought them solely because of reviews but they really are fantastic. Its nice to know its an established brand as well.

Killer job on the Advents! They sound wonderful you lucky devil. Never let them go!

1 Like

Yeah, JBL has been around forever and probably known as much for their pro audio line as their consumer. I think that back in the day, they were pro only, but consumers with enough capital bought them anyway, because you always saw them in recording studios.

1 Like

Oh man! Awesome post!
Giving new life to old beloved hardware, is so rewarding!

Well done!


Well you’ve officially gone and made me feel old. I anyone needs me I’ll be doing the paperwork for a Hoveround.

1 Like

Curious about the history of JBL and how it related to Altec Lansing, I found that the Wiki page is interesting for those who remember how awesome these speakers were/are still.

1 Like