From John Emond Sent Tue, Jan 9th 2018, 15:00
From John Emond Sent Tue, Jan 9th 2018, 15:00
Hi Tony, Thanks for sharing your knowledge. Do you know more about the RS202? I recal= l these sounding quite good and being very popular at one time.=20 Also, how about the Opus3? The chorus seems more subtle than the PolySix. Cheers, John Monde Synthesizer gives you More www.mondesynthesizer.com > On Jan 9, 2018, at 5:38 AM, Oakley Sound <xxxxxxxxxxx@xxxxxxxxxx.xxx> wrot= e: >=20 > For Kenny :-) >=20 > In my mind there are two basic string ensemble topologies, which I simply s= um up as the Solina and the Roland. >=20 > The Solina method uses three sound sources all modulated with a common LFO= (or LFOs) but with each sound source frequency modulated +/-120 degrees out= of phase with the other. It's almost always mono, but I think the later Sol= inas were designed for stereo output. The three sound sources are typically f= ed with a simple sawtooth from the keyboard electronics and then each sound s= ource is created with its own BBD and it associating clock driver. Examples;= ARP Solina, Korg Polysix ensemble mode, Yamaha SK20 et al. However, I think= the best sounding example of this genre is the Logan String Melody II. >=20 > The Roland method uses four sound sources each one modulated by either one= LFO or a combination of two LFOs; one low frequency triangle wave, and anot= her faster sine wave. Roland used four delay lines with a pair for each side= of the stereo channel. Examples: VP-330, RS-09, RS-505. Note their two earl= ier stringers, RS-101 & RS-202, used different systems. >=20 > The Korg Lambda and PE2000 use a variation on the Solina method, but unlik= e the Solina and Korg's own Polysix, they use three sets of high frequency V= COs (and the usual organ divide down technology) with each chain modulated w= ith two LFOs with the usual 120 degrees phase shift between them. This works= out to be the most complex of all but generates the least amount of unwante= d hiss and noise. Unfortunately, the Lambda's VCOs were placed so close to e= ach other on the circuit board they lock together and the rich ensemble effe= ct can only be heard if you use a large amount of detune or introduce vibrat= o. >=20 > The later Roland method tends to produce thinner sounding strings but they= do seem to sound better, perhaps more realistic, to my ears at least, when p= laying monophonic lines. >=20 > Roland did also use a single LFO in one case, the RS-101, which was then s= ent to a divider chain to produce half, quarter and an eighth frequencies to= drive each of the four BBD lines. It has a mono output but sounds closer to= the Solina rather than the later Rolands. >=20 > The ARP Omni falls into its own category I think. This is simply three sep= arate BBD lines each modulated with its own LFO. The actual ensemble circuit= board module allows for the dry signal to be mixed in with the effected sig= nal but this has been left unused in all the production versions I have seen= . >=20 > There are also some very effective string machines that use just two BBDs w= ith the Elka Rhapsody surely being the finest example. >=20 > Then, of course, there is the daddy of them all, the Freeman. It's probabl= y closer to the Korg Lambda with it's three (or two) divide down chains. As t= o what modulates them I have no idea. But from the pictures online of the in= sides of the two channel version it seems to suggest that they have no top o= ctave generator (TOG) but individual high frequency VCOs like the PS3100 and= other older organs. That should make it sound marvellous. >=20 > Tony