ben m
Joined: 15 Sep 2002
Posts: 337
Location: UK |
| Week 6 - Samplers 1 |
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Ok, here we go with the sampling questions;
01- What are the logistical disadvantages of multisampling?
02- What is the importance of 'zero crossing' with sampled material?
03 - What problems may there be with sampled material from vinyl in terms of pitch/tempo?
04 - What are the benefits of multisampling?
05 - What are the advantages of USB connectivity for a sampler?
06 - Why do some samplers offer SCSI connectivity?
07 - What is 'tracking'?
08 - Why might an LFO be used with a sample?
09 - What filters are commonly offered with contemporary samplers?
10 - How do 'soft samplers' such as Gigasampler store their samples?
11 - Why are Zip Drives used with some hardware samplers?
12 - How can a sampler be used to add a 'vinyl effect' to a song?
13 - What benefits do samplers with multiple physical outputs have?
14 - What are the benefits of working with mono samples over stereo samples?
15 - What MIDI control messages can a typical sampler read?
16 - How can an instrument with a long sustain be created from an instrument with a short sustain using a sampler?
17 - Aside from a MIDI lead, what other connections are (or can be) made from a hardware sampler?
18 - How does a hardware sampler ensure that there is no latency?
19 - How can sample looping be used to save storage space?
20 - What are the main requirements of a glitch free loop?
21 - Why are closed and open hi-hats often sent to the same mute group?
22 - On hardware samplers, how much sampletime would you typically get out of 64MB storage?
23 - How might you achieve a chorus effect using a sampler that does not have an effects section?
24 - How might you soften the start of a drum sample (single hit)?
25 - In which phase(s) of the envelope (attack/decay/sustain/release) might you place the loop in a sample?
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ben@audiocourses.com |
Tue Oct 07, 2003 11:30 pm |
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mommi
Joined: 21 Apr 2003
Posts: 47
Location: Tallinn, Estonia |
| Week 6 answers |
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Hi,
It has been an enjoyable reading this week. Here are my answers.
<url>http://www.soundonsound.com/sos/apr01/articles/practical.asp</url>
<url>http://www.soundonsound.com/sos/may01/articles/catchphrase2.asp</url>
<url>http://www.soundonsound.com/sos/jun01/articles/catchphrase3.asp</url>
<url>http://www.soundonsound.com/sos/oct99/articles/samplers.htm</url>
<url>http://www.iaekm.org/0301_fe2.html</url>
<b>01- What are the logistical disadvantages of multisampling?</b>
Multisampling is when the instrument's range is divided into smaller subranges and a different sample recorded for each range. This is to more realistically represent the instrument at different frequencies. Multisampling requires more memory, since just more samples are used to represent one instrument. Sure it is accompanied with more work as well.
<b>02- What is the importance of 'zero crossing' with sampled material? </b>
When looping sampled material and looking for seamless transitions from loop end to loop start point, it is advantageous to have the wave crossing the zero line at these points. This helps to avoid audible clicks in the looped material.
<b>03 - What problems may there be with sampled material from vinyl in terms of pitch/tempo? </b>
Pitch changes in the played material, caused by
a) Instability in the vinyl turning speed. The instabilities come from the driving mechanism (loose belt, motor instability).
b) Warped vinyls. These cause the needle to move up and down with accompaning pitch variatons.
<b>04 - What are the benefits of multisampling? </b>
Multisampling allows the creation of more realistic instrument sounds. In sampling, higher notes are produced by playing the sample faster and lower ones by playing it slower, with inevitably accompanying timbre changes. Problem is you cannot go too far from the original sample speed before the timbre changes become unacceptable. Multisampling approaches this problem by using different base samples for different note ranges of the instrument, so you don't have to change the playback speed too much.
Also, instruments tend to sound quite differently depending on whether they are played loud or soft. Multisampling can approach this problem as well.
<b>05 - What are the advantages of USB connectivity for a sampler? </b>
USB is a widespread external serial interface standard. Having USB connectivity gives access to USB-equipped computers, as well as to external storage devices.
<b>06 - Why do some samplers offer SCSI connectivity? </b>
SCSI is a fast parallel interface. Samplers can be connected to SCSI-equipped computers through this interface. A protocol named SMDI (SCSI Musical Data Interchange) exists that uses SCSI for the computer and sampler to talk to each other.
High capacity SCSI hard disks and CD-ROM drives can be connected through SCSI interface, as well as internal removable media drives like Iomega Zip or Jaz.
<b>07 - What is 'tracking'? </b>
When using filters, their effect depends on the pitch of the sound. By keyboard tracking, the filter cutoff frequency can be made dependent of the pitch. The tracking range can typically be varied from zero (no tracking) to two (filter cutoff frequency increases twice as fast as pitch).
<b>08 - Why might an LFO be used with a sample? </b>
Much for the same purposes as in synthesizers - to produce slow fluctuations in volume, timbre or pitch.
<b>09 - What filters are commonly offered with contemporary samplers? </b>
Low pass
High pass
Band pass
Notch filter maybe
<b>10 - How do 'soft samplers' such as Gigasampler store their samples? </b>
Soft samplers use the computer's internal hard disk for sample storage. The file format depends on software used, some programs use formats like WAV or AIFF that are generally understandable for a variety of software, some use proprietary formats. For operation - editing and playback - the samples are read into computer RAM.
<b>11 - Why are Zip Drives used with some hardware samplers? </b>
Sample storage is a memory-expensive business. Zip drives offer reliable removable long term storage.
<b>12 - How can a sampler be used to add a 'vinyl effect' to a song? </b>
a) Make the playback pitch of the sample to change slightly using an LFO
c) You may be able to select an appropriate effect in the sampler
b) Use sampled vinyl noise to mix it into the song
<b>13 - What benefits do samplers with multiple physical outputs have? </b>
Multiple outputs can be used to send sounds out of the sampler for modifying them using outboard effects and/or processors, or sending them to separate channels of the mixing console, for example.
<b>14 - What are the benefits of working with mono samples over stereo samples? </b>
Memory and storage benefits. Mono requires twice less memory compared to stereo.
<b>15 - What MIDI control messages can a typical sampler read? </b>
Most of them (Eg Note On, Note Off, Velocity, Program Change, Bank Select, System messages).
<b>16 - How can an instrument with a long sustain be created from an instrument with a short sustain using a sampler? </b>
Creating a loop in the sustained section of the sample. Or selecting the (originally) short sustain section and applying time stretching to it.
<b>17 - Aside from a MIDI lead, what other connections are (or can be) made from a hardware sampler? </b>
SCSI
USB
Analog in L/R
Analog out L/R
Assignable outs
Digital in
Digital out
Headphones
Word clock
<b>18 - How does a hardware sampler ensure that there is no latency? </b>
To eliminate the delay induced by hard disk read operations, the samples are read into RAM before an actual request for playback. (Borrowed the idea from Jules, please don't mind!  )
<b>19 - How can sample looping be used to save storage space? </b>
If there is a clear sustained section in the sample, a loop can be built basing on a part of it. So there is no need to keep the almost not-changing data in memory.
Or, if the sample is of cyclic nature (like a few bars of drum kit or other repeating figure), the whole sample can be looped throughout the song instead of copying it repeatedly.
<b>20 - What are the main requirements of a glitch free loop? </b>
The top and tail points of the looped section should have the same digital data value or, better yet, the wave should cross the zero line both at the start and end points of the loop.
<b>21 - Why are closed and open hi-hats often sent to the same mute group? </b>
Because in reality, open hi-hats never sound at the same time with closed ones. So when the sound of one of them is playing, the other must be muted.
<b>22 - On hardware samplers, how much sampletime would you typically get out of 64MB storage? </b>
It depends on sampling rate and bit depth. 16-bit at 44.1 kHz would give slightly less than 13 minutes in mono (5 MB per minute). Two times less for stereo.
<b>23 - How might you achieve a chorus effect using a sampler that does not have an effects section? </b>
Use two copies of the same sample. Delay one of them with respect to the other for ca 15-35 ms. Apply slight pitch changes by LFO, if available.
<b>24 - How might you soften the start of a drum sample (single hit)? </b>
Using an audio editor to make it softer. Or applying envelope so as to get a longer attack time on the sample.
<b>25 - In which phase(s) of the envelope (attack/decay/sustain/release) might you place the loop in a sample? </b>
Sustain. This is the part where the signal doesn't (shouldn't) change.
Cheers 
mommi |
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Fri Oct 10, 2003 5:55 pm |
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Albow
Joined: 02 Sep 2003
Posts: 27
Location: Spain |
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01- What are the logistical disadvantages of multisampling?
The logistical disadvantages of multisampling are concerned with
storage. Multisampling requires a number of samples to be
created so that each note can have a smaple close to its frequency.
This is because samples transposed far from their original pitch
can sound less realistic. To harbour more samples however, uses up more
memory/storage space on the computer/synthesiser hardware.
02- What is the importance of 'zero crossing' with sampled material?
http://www.futureproducers.com/site/mode/dictionary/switch/definition/id/131
Zero crossing is a convenient point to splice two sounds together as
the level of the splice points are the same at zero volts. This avoids
clicks when looping samples together.
03 - What problems may there be with sampled material from vinyl in terms of pitch/tempo?
As a vinyl record player is a mechanical device, the speed at which
every turntable plays will not be exactly the same. This will be due to
tensions in the belt or motor can only be approximated as it is non-digital. One belt could play ever so slightly slower than another if it is minutely looser. The tension and slack may also come and go slightly over the duration of a song. It would therefore be difficult to get the timing exactly right when super-imposing onto an exact, pre-pregrammed digital track, and it would be tricky to speed it up or slow down the sample to be at exactly the right speed. This could be exacerbated by the dips and warps in the vinyl itself, rendering the format too unpredictable for merging with a digital soundtrack.
04 - What are the benefits of multisampling?
Multisampling ensures that the sound produced is more realistic. As a note is sampled, the representation becomes less realistic if a sample of a note at one pitch is stetched through several pitches. With multisampling enough samples exist to avoid this occurring.
05 - What are the advantages of USB connectivity for a sampler?
The sampler can connect straight to a PC, and you could even perform drag and drop operations within the OS. You would also find cdplayers, mini disks and DAWs that are compatible with this format, and could be used to create and transfer samples.
06 - Why do some samplers offer SCSI connectivity?
SCSI interfaces are common on PCs, and is the industry standard for the transfer of data between sampler and hard disks, cdrom drives on a PC.
07 - What is 'tracking'?
When using filters, in order to offer a more realistic representaion of
a note at higher frequencies, the cut-off frequency of the filter has to be increased the higher the frequency of the note. This is tracking.
The filter cut-off frequency tracks the note throughout the keyboard.
08 - Why might an LFO be used with a sample?
To alter the pitch and timbre of a sound. It is the same as using an LFO for
synthesiser notes/sounds
09 - What filters are commonly offered with contemporary samplers?
Low pass
High pass
Band pass
10 - How do 'soft samplers' such as Gigasampler store their samples?
They are stored as SW applications on a computers hard drive and are loaded into the systems RAM as a resource to run as a sampler.
11 - Why are Zip Drives used with some hardware samplers?
They have more storage space than floppies, so are realistic for
storing samples which are large files. Also zip drives are portable and durable.
12 - How can a sampler be used to add a 'vinyl effect' to a song?
By sampling the soundof vinyl, looping it and using it as a
backing track while recording
13 - What benefits do samplers with multiple physical outputs have?
This enables the producer to mix in a number of samples at the same time, so that you could have a few loops going to for the base of the song accompanying a drum track for example.
14 - What are the benefits of working with mono samples over stereo samples?
Mono requires less processing and storage resources from the computer. It also mixes in more comfortably with the background track. It is easier to work with and add effects / edit.
15 - What MIDI control messages can a typical sampler read?
Note On
Note Off
Velocity
Program change
Bank select
16 - How can an instrument with a long sustain be created from an instrument with a short sustain using a sampler?
One way would be to elongate the sustain part of the note in the note
envelope. Otherwise you could take the note and stretch it.
17 - Aside from a MIDI lead, what other connections are (or can be) made from a hardware sampler?
SCSI
USB
Firewire
Analogue cable L/R
Optical fibre
Headphones
18 - How does a hardware sampler ensure that there is no latency?
Data is loaded into Cache and virtual storage in RAM so they are
accessed by the CPU and processed back and forth from the disk so that the data transaction occurs too quickly for latency to occur.
19 - How can sample looping be used to save storage space?
As opposed to storing tracks the entire length of the song, or the length of the bars for which an insert may last, as long as there is
repetition, small sample loops can be stored and used over again for the duration of the track, saving on storage space.
20 - What are the main requirements of a glitch free loop?
Zero crossing should be achieved at both the beginning and the end of the loop. The level will then be the same at zero volts and the transition will be seamlesss. Crossfading may be used to achieve this purpose.
21 - Why are closed and open hi-hats often sent to the same mute group?
Becuase the open sound should mute when it is closed and vice versa.
22 - On hardware samplers, how much sampletime would you typically get out of 64MB storage?
I don't know how to work this out. As this could be a cube root thing I'll go for 16.
23 - How might you achieve a chorus effect using a sampler that does not have an effects section?
As long as it has a delay effect, you could assign a delay of between 15 and 40 ms to achieve chorusing.
24 - How might you soften the start of a drum sample (single hit)?
Alter the envelope so that the attack time is longer. This smoothens out the impact of the intial sound that greets the ear.
25 - In which phase(s) of the envelope (attack/decay/sustain/release) might you place the loop in a sample?
Sustain. You want the loop to be constant and consistent. |
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Sat Oct 11, 2003 7:54 pm |
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Fenderocks
Joined: 09 Aug 2003
Posts: 26
Location: Music City, USA |
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01- What are the logistical disadvantages of multisampling? Takes a lot of time and takes a lot of disc space.
02- What is the importance of 'zero crossing' with sampled material? Zero crossing is a good and easy way to splice two sounds together when the level of the splice points is at the same as zero. This is a way to avoids clicks when looping samples together.
03 - What problems may there be with sampled material from vinyl in terms of pitch/tempo? With vinyl it’s difficult to change the tempo if the material if it is a little off also I’ve had a few vinyl records that our warp which would be a pain to try change.
04 - What are the benefits of multisampling? I’ve read that the quality of the sound on the keyboard is better.
05 - What are the advantages of USB connectivity for a sampler? It’s quick and easy to bring it off of the computer to right back on it.
06 - Why do some samplers offer SCSI connectivity? SCSI hard disks and CD-ROM drives can be connected, as well as internal removable media drives like Iomega Zip
07 - What is 'tracking'? It has to do a lot with filters and how to offer a better sound of higher notes, and when the cut off frequency of the filter is increased the frequency of the note is higher therefore creating tracking.
08 - Why might an LFO be used with a sample? To alter the pitch of the sound and to add expression for the wheel or effect.
09 - What filters are commonly offered with contemporary samplers?
Low pass
Hi pass
Band pass
10 - How do 'soft samplers' such as Gigasampler store their samples? By the computer hard drive in formats by wav. or AIFF that are read into the computers ram.
11 - Why are Zip Drives used with some hardware samplers? It’s more reliable and more can be store for a lot longer.
12 - How can a sampler be used to add a 'vinyl effect' to a song? The only way I can think to do this is to sample the sound of vinyl, and loop it in and using it as a backing track while recording the track.
13 - What benefits do samplers with multiple physical outputs have? To be able to bring in more samples at the same time, instead of doing one and then going back and doing another and then another.
14 - What are the benefits of working with mono samples over stereo samples? So you are not spending a lot of time processing the information and using a lot of storage. By using mono it gets a better sound when using with drum tracks I’ve heard, with easier ways to bring and effects.
15 - What MIDI control messages can a typical sampler read?
Eg Note On
Note Off
Velocity
Program change
Bank select
System massagers
16 - How can an instrument with a long sustain be created from an instrument with a short sustain using a sampler? Use time stretching, or creating a loop or an envelope.
17 - Aside from a MIDI lead, what other connections are (or can be) made from a hardware sampler?
SCSI
USB
Analog in L/R
Analog out L/R
Assignable outs
Digital in
Digital out
Headphones
Word clock
18 - How does a hardware sampler ensure that there is no latency? To make sure the sample is processed back in forth so quickly that latency can not occur and to do this by uploading the sample into the virtual storage (RAM).
19 - How can sample looping be used to save storage space? By taking a short sample and looping it.
20 - What are the main requirements of a glitch free loop? The crossing point is at zero but to have the loop or cross fade at the break with the crossing point.
21 - Why are closed and open hi-hats often sent to the same mute group? When the other one is being used the other one is to be muted.
22 - On hardware samplers, how much sampletime would you typically get out of 64MB storage? Not much but 380 seconds and 44’100
23 - How might you achieve a chorus effect using a sampler that does not have an effects section? Grab two of the same samples, set them up on different tracks, have one play a very little bit ahead with the pitch go up and down with a delay of 15 to 35 sec.
24 - How might you soften the start of a drum sample (single hit)? Lower the volume, or add compression, or you could raise the attack of you envelope shaper.
25 - In which phase(s) of the envelope (attack/decay/sustain/release) might you place the loop in a sample? Where the signal doesn’t change, sustain. |
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Sun Oct 12, 2003 5:16 am |
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indigojf
Joined: 03 Aug 2003
Posts: 12
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01- What are the logistical disadvantages of multisampling?
Multisampling requires more memory because it requires more samples for an instrument.
02- What is the importance of 'zero crossing' with sampled material?
You should strive to have the beginning and end of a sample be at a zero crossing to avoid pops or clicks when looping.
03 - What problems may there be with sampled material from vinyl in terms of pitch/tempo?
Records could become warped, or the pitch may be slightly off due to the playing speed of the turntable if mechanisms were damaged or loose.
04 - What are the benefits of multisampling?
Multisampling is a means of producing a more realistic sampled instrument by using a number of samples for different pitch ranges or dynamics of that instrument.
05 - What are the advantages of USB connectivity for a sampler?
This would allow you to connect it to a USB-equipped PC to import or export samples. Possibly other devices that support USB as well.
06 - Why do some samplers offer SCSI connectivity?
You could use SCSI to interface with a PC, connect to a hard drive to store samples, or read a sample CD by connecting it to a CD-rom.
07 - What is 'tracking'?
Tracking is when you can have the timbre of an instrument automatically change, according to the pitch it is played at, to create a more realistic sound.
08 - Why might an LFO be used with a sample?
You could use it to modulate the sound, much like in a synthesizer.
09 - What filters are commonly offered with contemporary samplers?
Low pass, high pass, and band pass filters.
10 - How do 'soft samplers' such as Gigasampler store their samples?
The samples are stored on a hard drive and then loaded into RAM for faster playback while in use.
11 - Why are Zip Drives used with some hardware samplers?
They are very portable and hold much more data than floppies.
12 - How can a sampler be used to add a 'vinyl effect' to a song?
You can record some vinyl noise and use it as a looping sample in the song.
13 - What benefits do samplers with multiple physical outputs have?
This allows greater flexibility in recording/mixing.If you have two outputs, you could assign a sample to play through each output and send them to the mixing console seperately from each other, and recording them to seperate tracks if you want. That would allow you to mix them independently of each other.
14 - What are the benefits of working with mono samples over stereo samples?
Mono samples are half as big as stereo samples, giving you more storage space.
15 - What MIDI control messages can a typical sampler read?
Note on and Note off, bank select, program change, and velocity.
16 - How can an instrument with a long sustain be created from an instrument with a short sustain using a sampler?
You could loop the sustain portion of the sample, or time stretch it.
17 - Aside from a MIDI lead, what other connections are (or can be) made from a hardware sampler?
USB
SCSI
Analogue Out L/R
Analogue In L/R
Assignable outputs
Headphones
Word Clock
18 - How does a hardware sampler ensure that there is no latency?
Data is loaded into RAM which is accessed quickly enough for no latency to occur.
19 - How can sample looping be used to save storage space?
You can loop the sustain on shorter samples, which would require less space than having longer ones.
20 - What are the main requirements of a glitch free loop?
The loop's beginning and end must be at a zero point so that the loop won't pop or click.
21 - Why are closed and open hi-hats often sent to the same mute group?
So that when the closed hi-hat is being played, for example, the open hi-hat will not. In reality they couldn't play at the same time. The hi-hat is either open or closed.
22 - On hardware samplers, how much sampletime would you typically get out of 64MB storage?
A minute of stereo audio at 44.1kHz uses about 10MB of space, so 384 seconds of stereo audio, or 768 seconds of mono audio.
23 - How might you achieve a chorus effect using a sampler that does not have an effects section?
Use two copies of the same sample, delaying one slightly and modulating it's pitch with an LFO.
24 - How might you soften the start of a drum sample (single hit)?
Using a slower attack in the envelope.
25 - In which phase(s) of the envelope (attack/decay/sustain/release) might you place the loop in a sample?
Sustain. This is when the sample remains steady and the looping will be smooth. |
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Tue Nov 04, 2003 2:12 pm |
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