DSJR
Major Contributor
'BBC Dip indeed!!!'
It's my memory that the Spendor BC1 which started all this 'BBC' nonsense in the early 60's, as basically flat in the lower khz region and a 4.5kHz narrow-band 'dip' was actually a measurement axis thing, the correct axis for this response ideal seemingly the Coles 'super-tweeter' (so 5 degrees above the main HF1300). The BC1's issues were elsewhere really, but back then, these were less of an issue unless a bad tuyrntable system as used as a source and with 'side open' RIAA phono stage with no lf filtering. The infamous LS3/5A had a 'quack' at 1.5khz rather than a dip above and the 5kHz resonance of the B110 driver which could show through, may have given an impression of a lower kHz dip, although I think it's a result of two flaws rather than deliberate - owners love 'em though for the 'deeeetail' they present.
As for later 'BBC designed' models with an upper mid dip in the response, I'd politely sugest (well not so polite) that the response errors were based on requests from sound editors and so on who listened up-close for hours on end - that's what I was told anyway and the poly cones they were using by then also had issues at these frequencies (the LS5/9 has a very 'soft' cone easily deformed apparently).
In the case of these Diamonds, they're not very costly, so driver characteristics surely have to be taken into account in the final 'voicing' of the product to sell to a mass market. I know Peter Comeau of old since his 1970's Heybrook days (but not Mr Fink) and deeply respect his skills and experience with speaker design. I'd echo the comment in an earlier post that these babies could be 'Harbeths for the cash strapped' as they do 'communicate' the music fairly similarly I think
It's my memory that the Spendor BC1 which started all this 'BBC' nonsense in the early 60's, as basically flat in the lower khz region and a 4.5kHz narrow-band 'dip' was actually a measurement axis thing, the correct axis for this response ideal seemingly the Coles 'super-tweeter' (so 5 degrees above the main HF1300). The BC1's issues were elsewhere really, but back then, these were less of an issue unless a bad tuyrntable system as used as a source and with 'side open' RIAA phono stage with no lf filtering. The infamous LS3/5A had a 'quack' at 1.5khz rather than a dip above and the 5kHz resonance of the B110 driver which could show through, may have given an impression of a lower kHz dip, although I think it's a result of two flaws rather than deliberate - owners love 'em though for the 'deeeetail' they present.
As for later 'BBC designed' models with an upper mid dip in the response, I'd politely sugest (well not so polite) that the response errors were based on requests from sound editors and so on who listened up-close for hours on end - that's what I was told anyway and the poly cones they were using by then also had issues at these frequencies (the LS5/9 has a very 'soft' cone easily deformed apparently).
In the case of these Diamonds, they're not very costly, so driver characteristics surely have to be taken into account in the final 'voicing' of the product to sell to a mass market. I know Peter Comeau of old since his 1970's Heybrook days (but not Mr Fink) and deeply respect his skills and experience with speaker design. I'd echo the comment in an earlier post that these babies could be 'Harbeths for the cash strapped' as they do 'communicate' the music fairly similarly I think