Which Tannoys, folks?

[Reffc]

Cheers Jon.

A little more progress. Sloping internal base is now in and braced very sturdily from underneath. Braces for one speaker are also in and rear panel is about ready to glue into place. Net internal volume works out at 158 litres, so the braces, front baffle internal laminations, ports and driver and bitumen sheeting take up a surprising 20 litres of volume.

I'm teetering on the edge of revising the porting arrangements to more an EBS design by lowering resonant frequency to 28 Hz to flatten out the bass response and remove the slight peaky response of the twin ports tuned for 33 Hz. The Alex Garner recommendation was 35 Hz with two ports but the response models as quite peaky and could lead to boominess in room. I know that I have a lift at 28/35/72Hz of over 6dB and that twin port tuning (200 long 100 dia) results in bass being just 3dB down at 38 Hz and -7dB at 30Hz.

A 120mm long single port is just -5dB down between 30 and 50 Hz before gently rising to zero at 500Hz. Seems a better tuning arrangement to me. The tuning is a remarkable 28Hz at -6dB which is some serious bass!

I'd be happy to take advice off anyone who's tried either of these tuning points for a cabinet between 150 and 170 litre volume plus any subjective impressions of in-room response. Need to know before midweek next week as that's when I'll be sorting the front baffles and ports!

The two tuning options are shown below. Green line is twin port 33.5Hz and red line is single port, 28Hz tuning: