I required a 1 kHz test tone recorded at 0 dB to calibrate the JL Audio XD400/4 full range amp,
Not only that;
When i contacted Adrian through eBay to ask if he knew where i could get my hands on a 50Hz Sine Wave tone Recorded at 0db on CD to calibrate the JL Audio XD300/1 Mono amplifier he was also able to supply it on a separate CD
Top man indeed as its almost impossible to find.
Note: never insert a cd with 50Hz at 0db in to a full range speaker as ive been told it will blow instantly,
This is why its normally only available at -20db,
However it is OK to use on a sub or mono amp setup as long as the full range are disconnected.