For this installment of Tips I'd like to talk about the DSP functions found in the Kurzweil K2000 and K2500. The DSP functions are used to optimize your samples. We will assume that you already know how to collect and keymap your samples. If you are not already familiar with this process you can refer to the Sampling Tips article originally run in the December 1995 issue of EQ. Getting To The DSP We'll need to load a sample into ram so lets use the "TIPS BASS" program we created last time. Once you've loaded this sample you'll need to get to the DSP functions in the Kurzweil. From the PROGRAM mode press EDIT. Then press KEYMAP, you should now be on the "EditProg*KEYMAP" page. From here you can now press EDIT. You should now be on the page called "EditKeyMap". Press the button labeled MIDI. You should now be on the page called "SampleRecordSamples:" This is the same page you did your sampling from.
Use your UP/DOWN and LEFT/RIGHT cursor arrows and the DATA DIAL to navigate around this page. Cursor to the top of the page, the area called " Samp: " , and select the sample you want to work with. If you are using our example this should be "TIPS BASS F2". With this sample highlighted press EDIT. You are now on the " EditRamSample " page. Press the DSP button. The NORMALIZE function should be highlighted.
Knowing The DSP Lets talk about just a few of the choices in the DSP section of the Kurzweil that we will use for our example.
Normalize: This will automatically boost your selected sample without distorting or clipping.
Truncate: This will find the START and END point of the sample. In this mode you'll notice a choice called THRESH: ( Use this to set the noise floor. This control has a range of -96 to 0db ) Once you've set the THRESH the TRUNCATE function will keep the samples that exceed the noise floor.
VolAdjust: This will allow you to raise or lower the volume of a sample or section of a sample. CAUTION - If you raise a sample too much you could distort it.
Clear: Use this to silence a portion of a sample without changing its length.
Delete: This will "Remove" the selected segment of a sample and change the length of the sample.
Volume Ramp: You can use this to create a "Fade" in or out between two points of a sample.
Resample: You can use this function to save memory by resampling at lower rates. This is also handy if your samples are "TOO CLEAN". Just resample that drum loop at a lower rate to add a little "Grit".
XfadeLoop: You'll use this to smooth your loops after you've found an acceptable START, LOOP and END point for your sample.
Using The DSP Now lets try some of these DSP functions on our "TIPS BASS" sound. First exit out to the "SampleRecordSamples:" page just to make sure we're all together. Select the first sample to be edited. This should be "TIPS BASS F2". From the "SampleRecordSamples:" page press edit. This will take you to the "EditRamSample:" page. Press the DSP button and notice that our first choice is NORMALIZE. Press GO. The K will ask " Keep this change " ? Before you answer, play the new sample. If you like it answer YES. The K then asks "Save TIPS BASS as : ID#200" ( Replace TIPS BASS ). Press REPLACE. The K will then put you back on the NORMALIZE page. Press Exit until you get to the "SampleRecordSamples:" page. Select the next sample to be edited. This should be " TIPS BASS C3 ". Press EDIT then DSP and repeat the steps used to NORMALIZE. Perform this NORMALIZE function on all the samples from our " TIPS BASS " example. This will give your samples "PUNCH".
EXIT out until you get to the " ProgramMode " page. You'll notice that the newly NORMALIZED samples are arranged in the same PROGRAM. Save this new version of " TIPS BASS " to disk.
Now we'll TRUNCATE our " TIPS BASS " samples. You'll need to get back to the "EditRamSample:" page. From here press DSP and with the DATA DIAL turn to the TRUNCATE function. Press GO.The K will ask " Keep this Change " ? Before you answer play the sound. If you like it answer YES. The K then brings you back to the TRUNCATE page. Press EXIT and you will now be on the " EditRamSample: " page. Press EXIT again and the K will ask you " Save TIPS BASS before exiting " ? Answer YES. The K then asks you " Save TIPS BASS as ID#200 " ( Replace TIPS BASS ). Press REPLACE. You should now be on the " SampleRecordSamples: " page.
Repeat these steps to truncate all the samples in your Keymap. After you've TRUNCATED all your samples exit out to the " ProgramMode " page once again you'll notice that the samples are still arranged in the same PROGRAM. Save this to disk.
We will now use the "VolRamp" function on a sample that decays naturally over time like our "TIPS BASS" sound. When sampling these types of sounds from some older synths you may notice some noise as the sound decays. This noise is present at the initial attack of the sound however you can't hear it because the sound is louder than the noise itself. The noise stays at a constant level but the sound itself is decaying and becoming lower in volume. As the sound fades and becomes lower in volume the noise becomes more apparent. When your faced with this type of noise you can use the "VolRamp" function in the DSP section to fade the sample and the noise at the same time.
Cursor over to the "EndLvl:" section of the display on the "VolRamp" page. Set the "EndLvl:" to -96dB and hit go. This will fade the sample along with any slight noise you may be hearing. When the Kurzweil has finished this fade it will ask "Keep this change"? Play the sound. If you don't like the new version of the sound answer NO. Remember if you do answer "NO" it will bring you back to the "VolRamp" page. At this point you can experiment with other settings or change the type of "Curve". I find that setting the curve to "LIN" works fine for this application. After you've used the "VolRamp" function all your samples exit out to the " ProgramMode " page. Again you'll notice that the samples are still arranged in the same PROGRAM. Save this to disk.
The "Resample" function could be very useful to musicians who would like to conserve memory. If you've been sampling in stereo and at 44.1 kHz this will certainly give you quality samples but it may be wasting memory. Certain sounds do not necessarily need to be sampled at 44.1 kHz. You may find that sampling at 32 kHz or 29.4 kHz is acceptable for what you are doing.
From the "SampleRecordSamples:" page select the sample you need to resample. Press EDIT and then DSP. Dial to the DSP page called "Resample". If your original sample was taken at 44.1 kHz try setting the "NewRate:" to 29400 Hz. On this page you'll also notice a choice called "Quick". Set Quick to "0". The "0" setting gives a quick preview of what the new sample will sound like. Press "GO". When the Kurzweil is done resampling it will ask "Keep this change"? Listen to the difference. If you like what you hear press NO (I did say NO). This will take you out to the "Resample" page in the DSP section. Now you can go to the "Quick" parameter and select "1". Now press "GO". This will take a little longer but it will give you the final version of your resampled sound. When the Kurzweil is done it will ask you "Keep this change"? Play the sound. If you like the new sample answer yes. If not, answer no and the Kurzweil will take you back to "Resample" page. Here you can experiment with other sample rates till the sample sounds like you want it to.
Until Next Time... Stay Well.
This article appeared in the September 1996 Issue of EQ Magazine.