That's possible. How you do it, depends on the samples you are using.
With looped samples you can do it as follows: duplicate the samples in the instrument section as many times as you want it to be echoed. For each duplicate you have to alter the envelope by first enter a parameter in the delay section how long it lasts before the echoed sound appears. Enter within attenuation the amount of decibels for each duplicate the volume decreases. I've tried something to figure out how it's possible and added a SF2 with this post. Perhabs it can help you as a reference.
It happens though the echo only will be heard as long as you'll keep the keys pressed.
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Another way - more suitable for longer lasting samples, is by adding silent audio with an external audio editor. The silence has to be as long as you want the desired echo to be.
Of course you don't want such a delay after pressing the keys on the keyboard. You can compensate that within sample start offset which you can find in the instrument section. Suppose you're using samples of 44100 samples per second and you've added 5 seconds of silence at the beginning - because you want the echo to last for 5 seconds - then for the first sample you have to enter 220500. Then you'll enter a command to start playing the sample from that point instead of the beginning. When you want each delay to last for 0.25 seconds next to eachother you probably know that's equal to 11025 samples. So the first delay contains a sample start offset of 209475, the second 198450, etc.
By entering a long lasting release time you can make sure the echo will be heared after releasing the keys.
if you work in a midi editor it is (for a single OrchestraHit) easyer to add an extra track OrchestraHit and have it played a Hit at the desired moment and volume. delays in a soundfont will always play independent from the tempo of your music.
regards bottrop
In general it's better to add delays or any other effect within the application you make music with instead of programming them with Polyphone or other applications to create sampled instruments.
Bottrop, you are absolutely right delays and echos programmed with Polyphone cannot be synchronized with the tempo of the music.
But perhabs he has specific reasons to add an echo into his instrument. Also within the GM2-standard and the MT-32 from Roland there's a patch called "Echo Pan" which contains this.
