As a past owner of a 4-voice, a 2-voice, various SEM modules and once
hosting a website of Oberheim Schematics (an EM magazine pick-of-the-
month) I am very familiar with the sound of the SEM. It has been some
time since I owned a Oberheim (i still have all the schematics
though!) so this is from very strong memories. I think there is
nothing quite comparable to a 4-voice played in unison mode - a very
huge sound. I can't say the component parts of a SEM are very
remarkable. A SEM can be easily made with most modulars today.
Especially the basic low-pass filter sound commonly used. The filter
was a standard 12db/oct multimode with a knob to mix through the
modes - a standard multi-mode with a mixer module will give you more
options than the SEM did. The VCOs were Saw and Pulse - you can get
more waveforms and mix them too. The Envelope generators were simple
ones Attack Decay Sustain also easy to get. They were pretty snappy
if needed. The main "sound" that the 4-voice had, the sound I think
you seek, was the product of having 8 VCOs playing at once and not
being exactly in tune. it is like the difference between one violin
and 8 - a big difference. Most polyphonic synthesizers today have
VCOs that are derived from one clock source and the add variation or
purposely de-tune slightly to get a fatter sound. With a modular,
each VCO will be out of tune also but the pitch relationship between
VCOs will change over the playing range (because of tracking errors)
and also over time (because of thermal reasons). The keyboard had a
couple of modes. The common lowest note priority - highest note
priority and the awesome unison mode (split-able between keyboard
halves) but the most unique mode was the scanning one. With each
keypress a different SEM was played. This meant with a 3-note chord
played a very cool choral sound happened - it was fairly hard to get
the SEMs to sound exactly alike.
I think you can get very close to the Obie sound with a modular. I
think you can surpass it even. It will cost you some cash and a tone
of space. Ask Bakis - he has a few SEMs and enough Doepfer to make a
good 4-voice emulation I'm sure (it sure looks like it in his
pictures!). I think the key is - buy tons of modules!

-James

On Apr 13, 2008, at 3:44 PM, John Talbert wrote:
> Hi, Mark! Thanks for the recommendation. I'd forgotten about the
> AH list.
>
> I realize I'll need essentially one mono synth worth of modules for
> each voice (vco, envelope, filter, vca, panner). Right now I have
> enough of those as well as a MCV24 to manage the polyphony. Although
> I only have one SEM module at the moment, I'll get more if this
> experiment works. I just want to find out if I can really get the
> sound of an Oberheim 4-voice, and if so, I can finally stop
> entertaining thoughts of spending $5000+ for a second-hand one on
> eBay. I'm just too worried that spending that kind of cash on
> something that old is just too big of a risk.
>
> Kindest regards,
> John
>
>
> On Sun, Apr 13, 2008 at 4:00 PM, Mark Pulver < mark@... >
> wrote:
>>
>>
>> As a thought, you might also wanna pop in on the Analogue Heaven
>> list and
>> ask this question. That can increase your chances of finding
>> someone with a
>> 2 -4 -8 voice, or even the single SEM you're looking for.
>> Subscription info
>> is here:
>>
>> http://machines.hyperreal.org/Analogue-Heaven/
>>
>> One thing to keep in mind as you build up a Doepfer based SEM
>> multi- is
>> that one thing behind the power that comes from a real 8 voice is
>> that each
>> voice is NOT exactly the same as the others. Even the slightest
>> extra tweak
>> of resonance, cutoff, attack time, etc., coupled with panning the
>> multiple
>> voices across the stereo spread (but never HARD left or right!)
>> adds to
>> that lush power... Much like Phil Spector's "Wall Of Sound"
>> technique.
>>
>> Good Luck!
>>
>> Mark
>> ------
>>
>>
>> J. Talbert (09:45 AM 4/13/2008) wrote:
>>> Hi, folks!
>>>
>>> I haven't posted here much since I came here for advice on
>>> purchasing
>>> my first A100 modules. But I can happily say that my A100 has grown
>>> quite a since those first 12 modules you guys helped me pick! So
>>> here's what I'm hoping someone here can help me with now...
>>>
>>> Ever since Joe Zawinul appeared on the cover of Keyboard magazine
>>> decades ago with his Oberheim 8-voice, I've had an intense desire to
>>> own at least a 2 or 4-voice. However, I'd rather not spend the kind
>>> of money these things are going for these days (especially given
>>> their age). So my crazy quest is to try and patch something that can
>>> sound reasonably similar on an A100 and *maybe* even a Nord Modular
>>> G2 or G1 (yeah I know they're not analog, but it's really just for
>>> fun in that case). Unfortunately, I can't find the sound of a raw
>>> SEM. I believe I've already got the necessary A100 modules and of
>>> course the Nord Modulars have an endless number of modules to build
>>> from. What I'm hoping someone can provide are short WAV recordings
>>> of:
>>>
>>> - Note (single voice) with saw, square and pulse waveforms
>>> - Note with a slowly opening and then closing filter (no resonance)
>>> - Note with a slowly opening and then closing filter (mid resonance)
>>> - Note with a slowly opening and then closing filter (full
>>> resonance)
>>> - Filter only (self resonating)
>>>
>>> I would also like a brief description of how voice allocation works
>>> on a 2, 4 or 8 voice in terms of how SEM banks are assigned. And of
>>> course, if there are other quirks that this instrument has which
>>> contribute to it's sound that I might need to know about, please
>>> include that information as well (like envelope behavior, sequencer
>>> strangeness, etc.)
>>>
>>> I hope this all isn't too much to ask, but I'd really like to have a
>>> proper reference point before I embark down this path. Of course,
>>> even if what I'm attempting is absolutely not possible to come close
>>> to, I can appreciate that feedback as well - just know then that you
>>> may be sending me into great debt as I try to get hold of a real
>>> Oberheim 4-voice! :-)
>>>
>>> Also, if someone here can make the recordings but need a place to
>>> host them, I can set up an FTP location. If the files can be
>>> compressed with WinRAR, that should greatly reduce the file size.
>>>
>>> Thanks!
>>>
>>> Kindest regards,
>>> John
>>
>
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