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Sometime in December 2013 I undertook the task of refoaming an entire set of Infinity Crescendo speakers as a combination birthday/Christmas present for my brother-in-law. He had purchased the speakers in question sometime in the early 1990's and over the years they had fallen into a somewhat sad state. The speakers still played just fine but the foam surrounds on most of the drivers had deteriorated pretty badly. None of the voicecoils had been damaged and the crossover components were still in good shape.

Our speaker guests for this exercise were:
Infinity Crescendo CS3009 - 1x EMIT-R Tweeter, 1x 4" IMG Midrange, 1x 6-1/2" Midbass Coupler, 2x 10" IMG Woofers
Infinity Crescendo CS3007 - 1x EMIT-R Tweeter, 1x 4" IMG Midrange, 2x 8" IMG Woofers
Infinity Crescendo CS Video center - 1x EMIT-R Tweeter, 2x 5" IMG Midranges (video shielded)

What follows are my observations on the refoaming process as it applies to the Crescendo series, some of the techniques I used (and the mistakes I made) and tips for success.

Before I started the process I did my fair share of reading and video watching on speaker refoaming; almost all of which call for removal of the dustcap in order to shim the voicecoil to keep it centered and prevent voicecoil rub. With the Infinity Crescendo series you don't really want to do that due to the inverted dustcaps being near impossible to get replacements for. Complicating this even further is that the Crescendo series uses a plastic trim ring that in some cases is glued on. So, what to be done? Read on...

Tools & Supplies:

hex key driver set

utility razor blade with many spare blades

superglue (several tubes)

paper towels

needle nose pliers

isopropyl alcohol (91 vol%)

wooden kitchen matches or toothpicks

replacement foam surrounds

speaker foam adhesive

craft brushes (several)

These last 3 will probably be included in a kit if you ordered a refoaming kit for your Crescendos on eBay or Amazon.


Murphy's Oil soap

Armor All

lazy susan

ziplock back for mounting screws

digital multimeter with resistance test setting

Work Area:

good work light

cardboard to protect your surface from cuts and scratches

the ability to leave a mess for days at a time

Test Tone Source

PC, laptop or tablet, connected to...

an amplifer or receiver

speaker wires that reach your work area

a pair of alligator clips or speaker spade connectors on the wires

and YouTube, search for "50Hz Test Tone 10 Minutes"

The test tone setup is used to check for voice coil rubbing when doing the final gluing of the new surrounds to the drivers. I've read some advice online that this sort of test tone "auto-centers" the voice coil in the gap, but this isn't strictly true. The test tone just gives a very audible feedback that your voice coil isn't aligned/centered properly.

If in doubt about the condition of a speaker voicecoil you can use a digital multimeter to individually check the impedance. After removing the speaker from the cabinet, set the multimeter to "resistance" or "Ohms", using the lowest meter tier. Each driver in the Crescendo series should have a 4 Ohm rating when measured across their individual terminals (in my case, anywhere from 3.6 to 3.8, round up). If you get a reading of "0" then the voice coil for that driver is likely damaged/destroyed and you will have to obtain a replacement driver.

This guide assumes you have removed the drivers from the cabinets. To remove the drivers you will need a hex-key driver set. None of the drivers are glued to the cabinet but they can be a little stubborn to remove due to the tight tolerances and age of the speakers.

You probably are starting with a driver that looks like this:

As you can see the foam surround has completely deteriorated and bits are missing. The outside of the surround is under the plastic trim ring with no apparent method to remove it.

The first step is to remove the loose foam, a finger will do.

It's important to try and not move the cone too much during the cleaning process. The surround combined with the spider (the ridged fabric under the cone attaching it to the driver basket) provides support for the cone and voicecoil. If the voicecoil gets knocked around too much it can deform it and/or break the coil wires and then you have a much bigger problem.

After you get the loose bits of the foam surround removed, it's time to get that trim ring off. Note that this only applies to the smaller drivers in the Crescendos, in my case the 4" and 8" of the CS3007 and the 4" and 6 1/2" of the CS3009. The trim rings on the 10" woofers of the CS3009 are not glued on.

Starting from the bottom side, gently but firmly start to work your razor blade between the driver frame edge and the plastic ring edge. You will want to work your way around the outside edge multiple times, slowly working the plastic away from the metal and adhesive that Infinity used. It's a black, hardened adhesive that is a total pain to remove.

Alternate your efforts on the topside by pushing the razor blade under the plastic ring and applying force until you feel the tip of the blade "push through" the adhesive under the trim ring outer edge. This will seem to take forever. Go slow and be patient. Be extra careful not to nick the cone!

After a small eternity you will be rewarded with a separated trim ring.

If you accidentally crack the trim ring you can carefully superglue it back together. I did this on one of the 4" drivers myself; the smaller rings are much harder to remove and weaker where the screw holes are.

After you get the trim rings removed you will need to scrape their backsides using the razor blade to get as much of the old surround and adhesive off as possible.

Now you begin the scraping process...

Using your fingernails, begin to remove the old foam surround and adhesive that is still stuck to the driver cone. Continue to work your way around the edge until you end up with a uniformly clean surface that feels slightly gummy, but is foam free. For the outside basket edge you can use your razorblade to scrape all of the old foam and adhesive down to bare metal. Just to give you an idea for the time involved, I spent about 45 minute per driver for this step.

After you have done the mechanical removal, wet a piece of paper towel with the isopropyl alcohol and begin cleaning the adhesive off the edge of the IMG driver cones. Since they are not paper we don't have to worry about altering the consistency of the cone material. Remember you are going for damp, not wet, with the goal of removing the glue. Use multiple towels and keep working until the towel comes away clean (the first ones will come away BLACK).

Set aside the driver and let it dry for 10 minutes before the next step (or in my case, move on to the next driver).

Taking one of the replacement foam rings, dry fit it to the cleaned driver.

The idea here is to get a visual reference of where the inside of the new foam surround will sit on the cone of the driver. This will be where we will be putting the glue.

I don't have photos for the next steps, but here is how you want to do your gluing:


1. Apply a thin, even layer of glue to the underside of the new foam surround inner ring.

2. Apply a thing, even layer of glue to the top edge of the IMG driver cone (use the old glue lines as a guide, generally)

3. Wait about 3-4 minutes after you finished your glue application. I use this time to clean the brush with tap water. The glue should be tacky on both driver and surround.

4. Carefully align the surround with the driver cone and gently press down with light taps.

5. Work your way around the driver, supporting underneath the cone with your fingers while lightly pinching/pressing the foam surround to the driver cone.

6. Keep working around the edges, pressing down any sections that raise up. After about 5 minutes you should stop getting any lifting.

7. After about 10 minutes check one more time to make sure there has been no lifting, press down if there has been.

So long as your glue layer was even and thin you will have a good bond. Applying too much glue will make the anti-lifting fight a longer process.

Finally, set aside the driver and let the glue dry for AT LEAST 5 hours! Overnight is better.

***optional extra gluing for larger drivers***

For the 8" and 10" IMG drivers I like to turn them over (supporting them just on the edge of the driver baskets, don't let the new surrounds get deformed) and apply a trim/dress strip of glue to the underside edge where the foam surround meets the driver cone. This gives a small additional seal/support to your gluing job. You won't be able to do this for the smaller drivers, and they really don't need it.

After the inside edge has fully cured you are ready to glue the outside edge of the new foam surround to the driver basket. For this step you will need to setup your test tone generating source, which will vary depending on what you have available. In my case I had my HTPC connected to an old Radio Shack 100 watt PA rack amplifier and then some hook-up wire from the speaker terminals to my alligator clips. You will want to have your tone generating setup ready to go BEFORE you start this part of the gluing process.


1. Lift up the outside edge of the of the foam surrounds and begin applying a thin, even layer to the underside of the outer edge.

2. While still holding up the newly glued section of surround, apply glue to the driver basket frame.

3. As you work around the circumference of the surround, place your kitchen matches or toothpicks between the surround and the basket to keep them separate while the glue starts to cure.

4. Work your way around the entire surround edge.

5. Wait 3-4 minutes after you finish the last of the glue application. (Clean the brush with water). The glue should be tacky on both the surround and the driver basket frame.

6. Turn on your test tone setup and start the YouTube video. Your amplifier should be down very low as you do not want to overdrive the drive, especially if you are working with the midrange drivers. You also have to consider that the individual drivers of the Crescendo series are 4-ohm rated, whereas most home amplifiers are expecting a minimum 6-ohm load. At a low volume you will be relatively safe for both driver and amplifier.

7. Connect the alligator clips to the terminals of the driver (polarity doesn't matter here). You will begin to hear the driver hum.

8. Remove the matchsticks/toothpicks and begin to lightly press down the outside edge of the foam surround to the speaker basket.

9. If you hear a LOUD rubbing or metallic chattering then the voicecoil is rubbing within the magnetic gap of the driver magnet. While the glue is still pliable, shift the cone gently until you no longer hear the rubbing.

10. With the test tone leads still connected, pick up the driver and move it around to make sure that the voice coil is not rubbing even when the driver is positioned "vertically". You will want to check it in multiple directions/angles.

11. Keep working around the outside edge, pressing down any lifted areas, for up to 5 minutes.

12. Re-check for lifting at 10 minutes, press down if found.

Let the glue dry for at least 5 HOURS. Overnight is better!


I like to add additional glue to the outside/basket edge, overlaying the existing glue and creating an supplemental seal. Squeeze a generous amount of glue around the outside edge of the foam surround edge/basket and use a brush to even the layer. Do not apply the glue to the "roll" of the surround, only the flat portion that is glued to the driver basket.

After everything has dried thoroughly, you may want to re-test with the tone generating setup to ensure that the voice coils haven't drifted while drying (unlikely, none of mine did).


Before doing this step you may want to optionally give the trim rings a light wipe down with Armor All, it really dresses them up nicely. Just be sure not to get it on the back where we will be applying glue.

1. Apply 4-6 drabs of glue on the underside of the trim rings

2. Press the ring down firmly on the driver, aligning the mounting holes to the holes in the driver basket.

3. Put the drivers aside to dry for an hour or two before re-mounting to the cabinets.


The particleboard panels used to make the Infinity Crescendo series are actually very robust, 3/4" thick on the face. That said, unscrewing the drivers from the cabinets can sometimes chip the mounting holes some. As an optional step, I put a few drops of superglue in each mounting hole to give the mounting screws something extra to bite in to when re-assembling.


After you have the drivers out of the cabinet it is the perfect time to give the exterior a good wipe down with diluted Murphy's Oil soap. I dilute about 1 tsp (5mL) in 8oz (240mL) of warm water and wipe the cabinets down with a cloth.


When putting the drivers back into their mounting holes you may want to use a pair of pliers to lightly tighten the speaker spade connectors for a better connection. You could also use electrical contact cleaner. To be honest Infinity didn't go all out on wire with these speakers; the hook-up wire inside the cabinets is 16g basic tinned copper.

When screwing the speakers back into the cabinets, use a star-pattern to apply torque to the screws to avoid warping the driver baskets.

Test your speakers to ensure that none of the voice coils are rubbing.

Here is the pair of CS 3007 being put through their paces.


The two midrange drivers for the Infinity Crescendo CS Video speaker are video shielded. In my case I obtained the CS Video from a seller on Craigslist that had refoamed them with a bit of overzealous gluing.

CS Video, here on the left is a cleaned driver, on the right is the driver as received.

CS Video, Left: gluing in the new surround, Right: original as received.

CS Video, both drivers refoamed with a new surround.

CS Video, remounting the drivers in the cabinet. Note the custom trim rings (not glued) and the inset mini screw for the mounting point under the EMIT-R tweeter.

The 10" IMG drivers of the CS3009 are a completely different beast than all of the other Crescendo series drivers I dealt with.

Instead of a stamped basket, the 10" use a cast basket with a MUCH more robust magnet structure, including a bumped back.

The foam/rubber surrounds on the 10" drivers were actually in very good shape (probably did not NEED to be refoamed at this point). They used a different type of adehsive on the surrounds (much stronger) and the surrounds themselves are a different material (better) than that used for the other CS drivers I dealt with. I did refoam the 10" drivers since I had them in the kit I received.

Here is a pair of 10" Infinity Crescendo drivers after having been refoamed.

Infinity Crescendo CS3009 re-assembly, woofers.

Infinity Crescendo CS3009 re-assembly, midrange drivers.

Infinity Crescendo CS3009, refoam completed.

Infinity Crescendo 4" midrange and 6 1/2" midbass coupler driver backside. Note the stamped baskets and comparable magnet assembly sizes.

Infinity Crescendo 4" midrange and 6 1/2" midbass coupler driver refoam completed.


Razor blades are sharp. In the course of completing this project I managed to injure myself only once, but it was quite an event. The pointy end of the razor blade went directly into my thumb. Messy. Deep. Non-PG comments were made.


Completing the refoam of the CS3007, CS3007 and CS VIDEO took a total of about 6 weeks (for me) given that I could only intermittently work on the project between other responsibilities. In total, I would budget about 6-8 hours of total effort (not including drying time) for each pair of Crescendos that you want to refoam, with most of that effort being all of the mechanical scraping that has to be done.

Be patient. Detail counts. Test and re-test after gluing and re-assembly steps.

Don't try to do too much gluing all at once. Go slowly and be precise with your glue application. The Crescendo series is as much about physical appearance as they are a sonic experience.

After giving each pair a very thorough "test listen" over several days I have to say that the CS3009 completely blow my Polk R50 out of the water. They just don't make speakers like this anymore. Monolithic beasts that they are, you can tell that Infinity was more concerned about making sure that these speakers performed than they were about trying to get them to fit in some designer constrained footprint or slim-width cabinet. If I ever have the chance to get ahold of a pair of these for myself, I will jump at the chance, and so should you.

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Am totally blown over by the job you did re-foaming the Infinity speakers. The documentation is superb and I can't tell you how much I appreciate having it available for future reference.

Became an Infinity owner/devotee back when your brother-in-law did and just began the process of resurrecting the four speakers I own for renewed listening pleasure. Only two of the mid-range speakers needed re-foaming and I took the easy way out and sent them to a place in Rochester, NY. They only charge $29.00 per speaker and seem to be extremely knowledgeable and audio-friendly (I can only hope they're at least half as exacting and detail-oriented as you obviously are).

Thanks so much for your excellent report, robert

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Originally Posted by zieglj01  /t/1517409/adventures-in-refoaming-infinity-crescendo-series-speakers#post_24517770

The Crescendo series will blow more than just the Polk R50 speakers, out of the water.

They are one of the better sounding Infinity speakers, that were made.

Thanks, for sharing the DIY speaker refoam education..

There were Kappa speakers in a plain cabinet with an IMG mid instead of the polydome (which a lot of people actually prefer). It was the steal of the '90s for the price, especially when they went on closeout. Very glad I grabbed a pair of 3006's.

Also thank you for the DIY King, I need to have my 3006's refoamed. Haven't decided if I'll send them in or to do it myself, if I do it myself, this will definitely helpful.

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Discussion Starter · #6 ·
Thanks for the appreciation guys. I wanted to give something back to the AVS community after all of the great advice and knowledge that I've gleaned over the years.

ien2, I'd be totally willing to do the re-foam on your speakers for free but I think the distance between us would be cost prohibitive in shipping, even for just the drivers. The DIY route is really not that difficult so long as you take your time. The Crescendos truly are AMAZING speakers when they are back in full working order. I've still been looking for a pair somewhere reasonably close to me and have had no luck. I'm about to relent and go with some Polk RTi A12's; they'd be a good match for my CSi A6 center.

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It probably isn't too bad to do myself, what I was considering though was having Watkins refoam it. They go through the driver and see if it needs more than just refoaming, since they are the actual company that made the IMG's they can recondition them to the original specs if it's needed. I haven't decided yet if the price is worth it right now.

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Thank you very much for this very well thought out re-foaming guide. I have always wanted to buy vintage Infinity speakers and seen a lot of them on sale on Craig's list but was afraid to pull the trigger because of the need to replace surrounds. With this guide, I think I can take on the project with more confidence.


Do you know how you can examine the surround to determine if they need surround? I have seen some surrounds that started to crack but still sounds great.



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It probably isn't too bad to do myself, what I was considering though was having Watkins refoam it. They go through the driver and see if it needs more than just refoaming, since they are the actual company that made the IMG's they can recondition them to the original specs if it's needed. I haven't decided yet if the price is worth it right now.
Could you supply some info for Watkins?
I want to have mine redone.
Any idea what they charge??

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2 Posts
It probably isn't too bad to do myself, what I was considering though was having Watkins refoam it. They go through the driver and see if it needs more than just refoaming, since they are the actual company that made the IMG's they can recondition them to the original specs if it's needed. I haven't decided yet if the price is worth it right now.
Could you supply some info for Watkins?
I want to have mine redone.
Any idea what they charge??

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