Hello,
Did build this bluetooth speaker with drivers I had on hand from another project :
The bluetooth/amp section is powered by a Wondom (Sure electronics) JAB4 with 1701 DSP.
About 7,2 net litres for the woofer (plus stuffing to reach the optimum 8 liters), crossover at 204Hz because I feared for the life of the SPX31m. 1.5 litres for each full range.
- First manual equalizer (15 bands) iteratively measuring with UMIK-1, various Q
-- Lots of boost from 30 to 60 (which was foreseen with simulation)
-- Q=8 Bumps to correct at 32Hz (High bump) and 38Hz (Low bump)
-- Shift of the response curve around 10k (SPX31M suddenly looses 8db at 10k)
-- Bumps around 4k,8k,...
Equalizing done with grille on the speaker, impact is noticeable.
SPX-31M is not the one I would have chosen but with EQ we are already a step ahead from a Marshall Woburn that we could test on the same music (various), much more cleaner bass, very strong attack.
Cabinet are closed: bass reflex would have required a few more litres I don't have due do size (427mm x 300mm x 15mm including grille).
This is my first project with a DSP (Sigma Studio) and I'm quite surprised how this little chip can save a less than ideal response curve (form factor was not negotiable).
Was thinking about the Fountek FR58EX to replace the SP-31M, any advice on this little full range ?
François
Did build this bluetooth speaker with drivers I had on hand from another project :
- Monacor SPH200CTC (8" dual coil)
- Monacor SPX-31M (2,5" full range)
The bluetooth/amp section is powered by a Wondom (Sure electronics) JAB4 with 1701 DSP.
About 7,2 net litres for the woofer (plus stuffing to reach the optimum 8 liters), crossover at 204Hz because I feared for the life of the SPX31m. 1.5 litres for each full range.
- First manual equalizer (15 bands) iteratively measuring with UMIK-1, various Q
-- Lots of boost from 30 to 60 (which was foreseen with simulation)
-- Q=8 Bumps to correct at 32Hz (High bump) and 38Hz (Low bump)
-- Shift of the response curve around 10k (SPX31M suddenly looses 8db at 10k)
-- Bumps around 4k,8k,...
- Then second equaliser with 6 bands to make it taste to our like
- Finally bass/mid/treble controls which are very welcome because line-in and bluetooth do not show the same response curve (bluetooth has more mids)
Equalizing done with grille on the speaker, impact is noticeable.
SPX-31M is not the one I would have chosen but with EQ we are already a step ahead from a Marshall Woburn that we could test on the same music (various), much more cleaner bass, very strong attack.
Cabinet are closed: bass reflex would have required a few more litres I don't have due do size (427mm x 300mm x 15mm including grille).
This is my first project with a DSP (Sigma Studio) and I'm quite surprised how this little chip can save a less than ideal response curve (form factor was not negotiable).
Was thinking about the Fountek FR58EX to replace the SP-31M, any advice on this little full range ?
François
