This is the method I use for breaking in new raw speakers. It's a combination of recommendations I've gotten from Ted Weber, Tim at EarCandy Cabs, and online correspondence with Celestion.
- Begin mixing single notes with the open chords and vary the attack and type of picking both with a plectrum and with bare fingers. Again, at least 15 to 30 minutes before moving on.
- You can now start mixing in bar chords and moving further up the neck. Over the next hour or so expose the speakers to as wide a range of frequencies as possible. Mix in tonal adjustments on both the guitar and amp. Save the highest and brightest settings for last. Work up to them slowly.
- Of note* New speakers should be limited to one to two hours of usage at a time. Then give them a break. Come back later, give them a couple minutes to warm up, and continue.
- At this point you can start increasing the volume and add in a little crunch. Again, chords first and then mixing in single notes and lead patterns.
- For the very best sounding speakers try not to drive them into "speaker" breakup for at least their first 15 hours of usage. The speaker needs time to limber up. It's like daily warmups of a runner getting ready for a marathon. Each day a little longer and a bit more vigorous.
Each speaker is different. Some models will be sounding their best after maybe 25 hours of usage. Others may need 50 to 100 hours to truly sing as they were designed to. Hemp cones seem to take forever and many players give up on them too soon. Doped speakers will handle more abuse but lose a little of their optimal sound. AlNiCo models offer more compression and have a very sweet sustain because of this. Ceramic models offer more headroom, less breakup, and a crisper sound. Ceramics seem better voiced for extreme gain and bizillion note leads. AlNiCos are better for rich chords, vintage blues crunchy breakup, etc.
This is just my (Rick inmyhands) opinion based on info I've received from the builders and suppliers and my own personal experience. I hope someone benefits from it.