Promenade and the Prommer
The Prommer was originally intended as a stand-alone sound sampler and
EPROM programmer. With the help of Promenade, you can use
your computer along with the Prommer to do many new things.
You can preserve your EPROM sound data on computer files. By using the
EPROM/Read EPROM Data menu option, you can copy the contents of
the EPROM loaded in the prommer to local memory and view it in the
waveform window. You can then use the File/Save menu option to
save it to disk.
For example, let's say you want to save a copy of the bass drum sound
in a DMX because you are planning to erase the EPROM and reuse it for a
Here are the steps you would take, assuming the Prommer is already
connected to your computer and set up correctly:
- Turn off the DMX and remove the bass voice card.
- Remove the EPROM from the voice card and insert it into the ZIF
socket on the front of the Prommer.
- From the Options/EPROM Type menu, select 2732 or 2732A as the
EPROM type, and select the "One EPROM, One Sound" organization option.
The Audio or Data selection doesn't matter at this point, but it wouldn't
hurt to select Audio.
- Select the EPROM/Read EPROM menu option. Promenade
will send commands to the Prommer to set the
EPROM type you just selected, adjust the size of Prommer memory block 1
to match the EPROM, and read the EPROM into block 1. Then,
Promenade will read the data from the Prommer into its own
local memory and update the waveform display.
- Now, you can select the File/Save menu option and select a
new filename for the EPROM image. You will be warned if you choose a
filename that is already in use.
- Be sure to backup your computer data before you erase the EPROM.
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Burning new sound EPROMs
You can make your own recordings using your computer, or download sound
samples from the web and put them on EPROMs to use in your drum machine.
Here's an example of how you can program a downloaded sample onto an
EPROM for use in the bass voice card used for the previous example.
- Let's say that you have two possible samples you'd like to try, but
you're not yet sure which you want to use. The samples are
sample1.wav and sample2.wav.
- If you haven't already, set the EPROM type and organization as
described above in the first example. Be sure to pay close attention to
the EPROM part number and select the correct type.
Now, using the File/Open menu option, or by dragging and dropping
the file from Windows Explorer, open sample1.wav.
- Click on the waveform display to audition the sound through the
- Now, open sample2.wav and do the same, to compare the sounds.
- OPTIONAL: If you have the line output of your Prommer
connected to an amplifier and speakers, you can also audition the sound
through the Prommer. This will give you a chance to hear how the
conversion from Wave file to companded binary will sound. Use the Prommer/Send
Prommer Data menu option to transfer the sample to the Prommer without
starting the EPROM programming process. You can then use the PLAY button
on the Prommer to listen to the sample.
- Once you have decided which sample you want to use and it is loaded
in Promenade, load your blank EPROM into the ZIF socket on the
Prommer and then click the Program button. The sample will be
transferred to the Prommer and the programming process will begin.
- Watch the Prommer display. A countdown indicating progress
will be displayed, and when it finishes, the Prommer display should read
- When programming is complete, click the Verify button and
wait for the verify operation to complete. It is important to verify the
data, as the MIDI data transfers between the Prommer and Promenade
do not have error detection. The only way to tell if an error in the
transfer has occurred is through the verify process. Note: For the same
reason, you may occasionally get a false verify error, but if you re-verify
the EPROM and it checks out OK the second time, you can be pretty sure
that it is really OK.
- Now, you can remove the EPROM from the Prommer, install it in the
voice card and put the voice card back in the DMX.
- If the sound doesn't sound the same as what you heard on the computer,
there are a few possible reasons:
- The sample playback rate is different. Try adjusting the tuning
pot on the DMX voice card. Depending on the voice card, this might
have a range of somewhere between 12kHz and 32kHz. If your original
sample was recorded at 44.1kHz or higher, you may not be able to
tune it into range. Try re-sampling the sound using your favorite
sound editing software down to 22kHz or so.
- The voice card may have an amplitude envelope that is affecting
- The conversion from linear 16 bit to companded 8 bit will have
affected the sound and some nuances may have been lost.
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Selecting a good sample
Making a sample suitable for a drum machine is not always easy. There
are several things to keep in mind when selecting an existing sample or
recording a new one.
- Length of the sound vs. size of EPROM. The playback sample
rate and EPROM size determine the length of the sound that can be placed
on an EPROM for a given drum machine voice. For example, suppose we
want to make a new sample for the DMX Snare voice card. The DMX snare
has a higher than usual sample rate, usually around 33kHz. The EPROM on
the snare voice card is a 2732, which has a capacity of 4096 samples.
The time it takes to play back 4096 samples at 33,000 samples per second
is 0.124 seconds (124 milliseconds). That's about 1/8 of a second. So,
the new sample we choose for this voice should be very short. Any
reverb or echo on the original sample would be wasted, so we want to
find a nice dry sound with a short decay time.
When choosing an existing sample (downloaded from the web, for example),
choose one that is the same size as your EPROM, or shorter.
- Attack, decay and amplitude. When editing a sound for use on
a drum machine EPROM, there are a few things you can do to make it sound
as good as possible. First, crop off any dead time before the
initial attack of the sound. You shouldn't have more than a few samples
of silence before the sound starts. Second, try to fade out the sound
if it is going to be cut off abruptly otherwise. Some sound editor
software has this capability. If not, you can transfer your sound to
the Prommer and use its Envelope function, and then transfer it back to
the computer. And last, make use of the "Auto-scale WAV Files"
setting under the Options/Audio Settings menu. This will ensure
you are using the maximum possible headroom without clipping the signal.
- Choose a good sample rate. The best common sample rate for
DX and DMX sounds is 22.05kHz (half of the standard 44.1kHz). This
falls into the tuning range of most Oberheim voice hardware. You can
always experiment with pitching sounds up and down to other levels,
but in general, stick with this rate.
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Converting file formats
If you have downloaded a binary DMX sound file from the web and would
like to edit it using a Windows WAV file editor, you can open it in
Promenade and use the File/Save menu option save it as a
.WAV file. The conversion takes place automatically.
Conversion from any of the three supported formats is just as easy.
Special option for loading WAV files: Under the Options/Audio
Settings menu, you can select the option to "Auto Scale WAV Files".
This option will calculate the maximum signal level over the full length of
the original waveform and use this to set the level for conversion to
obtain the minimum wasted headroom in the binary version of the sample.
If this option is turned off, no level adjustment will take place, and
a quiet sample will remain quiet and the audio quality may suffer due to
a lower signal to noise ratio.
There are two other options for loading files.
Zero First Two Bytes" option eliminates a problem with some DMX
and DX voices where a faint high pitched whine can be heard if the
first two bytes are not close to zero in value. When this option is
selected and a file is loaded, if the first two bytes are not both less
than 4, they will both be set to zero. This option only applies if
the Audio option is selected under the Options/EPROM Type
The "Auto Detect BIN File Sample Rate" works on binary and
Intel Hex files. (Wave files already have their sample rate encoded
within the file).
It uses a feature of samples originally recorded on the Prommer to set
the Windows sample playback rate to match the original sample rate.
When a file is loaded into Promenade, if the value of the
first two bytes bytes of the file are 0, the playback rate will be set to
32kHz, if both are 1, the rate is 24kHz, 2 gives 16kHz and 3 sets the
rate to 12kHz.
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Dealing with code EPROMs
Operating system firmware EPROMs can be handled by Promenade as
well as audio sample EPROMs. There are a few special things to remember
when loading or saving data EPROMs, where it is important to get exact
copies without any modification of the data.
- Turn off the "Auto Zero First Two Bytes" option.
- Set the Data format option in the Options/EPROM Type dialog.
This ensures that any empty EPROM space is left as erased (erased EPROM
bytes are equal to FFh) in the case where a sparse Intel Hex file is
- Don't save data files in .WAV format. The resulting Wave file
would just sound like a lot of noise, and the conversion process is not
guaranteed to be reversible. Only use .HEX or .BIN file formats for
saving and loading data files.
- Don't worry that the waveform display looks weird. It's data, not
audio and is not supposed to look like a waveform. Blank parts will have
a line at the top of the display, other parts will be all over the place.
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Programming 8-bit linear EPROMs
A few drum machines use a linear 8-bit data format (Simmons, for one).
With a little extra effort, you can use Promenade and the
Prommer to translate a regular companded binary file into this
Load the sound you want into Promenade as usual, selecting
the appropriate EPROM type and other settings as you would for a DMX
Instead of pressing the Program button when you are ready,
use the Prommer/Send Data function to transfer the sample to the
Prommer. Then, using the Prommer control panel, select the
Program Linear command to translate the data as it
is being programmed. The Promenade Verify function will not
correctly verify a linear EPROM.
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Precautions and general advice
EPROMs can be damaged by exposure to static electricity and mishandling.
Practice static-safe handling of EPROMs. Ideally you should only work
on a grounded static mat while wearing an approved grounded wrist strap.
Practically, few people actually do this, but you can still reduce the
chances of equipment damage by following some simple guidelines.
- Use grounded power plugs to connect the Prommer, your computer and
drum machine to their power sources. Turn off but do not unplug the
power cables when removing and replacing voice cards in the DMX.
- Before touching any EPROM or circuit board, ground yourself by
touching the grounded metal case of the Prommer or your drum machine.
- If you are standing, do not move around or shuffle your feet without
re-grounding yourself afterwards. If you are sitting, do not move your
chair or shift in your seat.
- Keep EPROMs in anti-static bags or anti-static foam when not in use.
Do NOT use plain white styrofoam or plain plastic bags. Anti-static foam
is black or pink and anti-static bags are pink or silver-colored.
Handle EPROMs carefully so you don't bend or break the pins. Remove
them from standard IC sockets carefully, lifting a little bit at a time
from each end until they come out easily. Use a small flat-blade
screwdriver or right-angled probe hook to lever them out slowly.
Once they are out of their sockets, inspect the pins carefully and
straighten any that might have been bent. When you re-insert the EPROM
in its socket, be careful that all pins go in the right place, that
no pins get bent under and that the EPROM is oriented in the socket
correctly. A small pair of smooth-jaw long nose pliers is very useful
for straightening bent pins.
When using ZIF (Zero Insertion Force) sockets, there is a lever to
operate that releases the EPROM pins before removal. Be sure to reset
the lever to clamp down on the pins after reinserting the EPROM.
After programming and verification, label the newly programmed
EPROM before removing it from the programming socket.
You can use handwritten small paper labels (available at most office
supply stores), or 1/2 inch wide plastic labels made by an electronic
label maker. You will save yourself lots of trouble if you make this
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