Part 6 of 8 of the NB Audio beginner guide to speaker building. Start at Part 1 and the series contents.
This is a preview. The full guide is a free 19-page PDF. Get the free PDF
Your first measurement isn't about a perfect graph. It's about getting the same answer twice, then putting the second speaker through exactly the same test.
Expansion Guide 5 walks you through that first session. You don't need to understand graphs before you start: you read the first one together.
The setup
Two routes, and you only need one: a USB measurement mic (the guide uses the miniDSP UMIK-1) or an XLR mic and audio interface (the Dayton Audio EMM-6). Both join the same lesson once they're connected. Install REW, load the mic's own calibration file and check the setup before you measure.
The reference
Put the speaker and mic in marked positions, keep the test short and quiet, and check the levels. Then make the first measurement, save it, and make it again before you change anything.
The data
How to read the graph, how to compare the second speaker fairly, and what one position change does. It ends with a troubleshooting table and what to keep from the session.
Who it's for
It's written for someone with a finished speaker and a measurement mic, or one on the way. Use an assembled speaker with its proper crossover, not loose drivers.
What it won't do is pretend a room graph is crossover-design data. That's a later job, and the guide says so.
Expansion Guide 5: Measuring Your Speakers
Free PDF, 19 pages. Both mic setups in full, the calibration steps, the troubleshooting table and a sample session record.
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Previous: Part 5: Building the cabinet: the order of work, from panels to drivers (Beginner Guide, Part 5)
Next: Part 7: Designing the crossover: from the drawing to a working board (Beginner Guide, Part 7)