Don’t let rotted foam or cracked rubber ruin a perfectly good pair of vintage speakers. Repairing them yourself at home is easier than you think, but there is one crucial step you have to get right before you break out the glue: getting the right measurements.
Buying a replacement surround isn’t as simple as just knowing you have an "8-inch speaker." Different audio manufacturers used completely different chassis and cone dimensions. To ensure a perfect, airtight seal, you just need a ruler or digital callipers to take two essential measurements in millimeters (mm).
Here is exactly how to measure your speaker like a professional audio technician.
📐 The 2 Essential Measurements You Need
When looking at our replacement surround kits, you will see the dimensions listed in millimeters. Measure your actual speaker driver across the exact centre from edge to edge to find these two values:
1. Outer Diameter (OD)
This is the total width of the entire replacement ring. To measure this on your speaker, find the widest part of the old surround where it glues down to the metal outer lip (the basket) of the speaker frame.
2. Inner Diameter (ID)
This is the measurement of the very inside edge of the replacement ring.
Pro-Tip if you can't measure the old Inner Diameter: If your old foam is completely gone and you don't know the exact inner diameter, don't worry! Simply measure the width of the speaker cone itself, and then allow for a 5mm overlap where the new foam will sit on top of the cone. This 5mm overlap ensures you have a decent, secure gluing area to bond the new surround to the cone.
💡 2 Quick Tips for Accurate Measuring
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Always Measure in Millimeters (mm): Speaker parts are incredibly precise. Measuring in inches leaves too much room for rounding errors, which can result in a loose fit.
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Close Enough is Usually Good Enough: If your measurement is within 2mm to 5mm of a kit listed on our site, it will almost certainly fit. The foam and rubber materials have a small amount of natural flexibility.
Ready to Bring Your Speakers Back to Life?
Once you have your dimensions written down, you can head straight over to our Speaker Surrounds by Size Collection to find your matching kit. All of our premium repair kits come with high-quality surrounds, specialised T7000 speaker glue, and an applicator brush to make the job effortless.
If you get stuck or your measurements look completely unique, don't guess! Drop us a message through our website chat with your speaker's make, model, and dimensions, and we'll point you to the exact kit you need.