ben m
Joined: 15 Sep 2002
Posts: 337
Location: UK |
| Week 6 - Samplers 1 |
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Ok, here's the sampling questions - practical will be posted later today;
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 Apr 13, 2004 10:28 am |
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hoggs33
Joined: 09 Feb 2004
Posts: 55
Location: Nottingham, England |
Hi Ben - any idea when the practical will posted - I've pretty much finished the questions for this week so would like to get started on the practical.
Duncan. |
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Wed Apr 14, 2004 6:38 pm |
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griff505
Joined: 23 Feb 2004
Posts: 68
Location: Bristol |
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01- What are the logistical disadvantages of multisampling?
Multisampling – Many sample of an instrument will be taken from different points in its frequency range, for example a grand piano, the samples would then be mapped across the keyboard for playing like a real piano. This allows each note to have a sample relatively close to its frequency and avoids the unrealistic sounds produced when samples are transposed a larger distance from their original pitch.
Problem – To store a number of samples takes up a lot of memory / storage space on the computer / hardware.
02- What is the importance of 'zero crossing' with sampled material?
Zero Crossing - The point where the polarity of an electrical or sampled signal changes from positive to negative (or vice-versa) as it passes through zero. This is important when working with sampled material as at zero the sound sample will not make audible clicks as it loops.
03 - What problems may there be with sampled material from vinyl in terms of pitch/tempo?
The pitch will be affected by:
- The inconsistent turning speed of the record player - Caused by the record player being on an uneven surface, a faulty motor, an old drive belt.
- Warped Records – Old, poorly stored, records often warp out of shape and as a result will have pitch and tempo variations as they are played. This will be picked up when the records are being sampled.
04 - What are the benefits of multisampling?
Multisampling – The advantage of multisampling is that it allows a more realistic representation of real instruments. If a single sample is used as a source for an instrument the timbre will suffer as the sampler simply speeds up or slows down the sample to change the pitch. Multisampling uses a number of samples spread across the keyboard, each of which does not have to be stretched too far from their original pitch. Multisampling can also provide different sampled depending on the velocity keys are pressed which will more accurately represent the velocity response of a real instrument.
05 - What are the advantages of USB connectivity for a sampler?
UBS allows a sampler to be direct connected to a computer, this allows for samples to be dragged and dropped straight from the OS to the sampler. This allows sample to be edited on the computer (much easier than the fiddly little screen on the sampler) and then loaded into the sampler which will take strain off the CPU as opposed to a soft-sampler.
06 - Why do some samplers offer SCSI connectivity?
Some samplers have SCSI connectivity. SCSI is a fast connection (80 Mbps) and was the most common connection before USB and Firewire. The SMDI protocol (SCSI Musical Data Interchange) allows for the computer to talk to the sampler using a SCSI connection.
07 - What is 'tracking'?
Keyboard ‘tracking’ or pitch ‘tracking’ is found in the filter section of a sampler. It determines how much the filter cutoff frequency is affected by the pitches being played. Tracking range can be varied from zero (no tracking) to two (cutoff increases twice as fast as pitch). On some synths, it can also be inverted, causing the cutoff frequency to move down as the pitch moves up. With careful adjusting ‘tracking’ can add life to a dead sound or smooth a raspy, over-bright sound. It’s also useful for high-resonance filter effects in which you actually hear a tone at the filter's cutoff frequency.
08 - Why might an LFO be used with a sample?
Samplers offer some synthesis features, allowing you to mangle the pitch, tonal-quality and volume in real time, under the control of onboard LFOs.
- LFOs can be routed to filter frequency; at their maximum speed setting they can create FM synth-like effects.
09 - What filters are commonly offered with contemporary samplers?
Notch, High Pass, Low Pass, and Band Pass 12 dB and 24 dB Filters.
10 - How do 'soft samplers' such as Gigasampler store their samples?
Soft samplers stream data from the hard disk, although to reduce latency the first parts of the audio samples are stored in RAM. Some new soft samplers have options allowing the user to configure how much data can be pre-loaded in RAM. Therefore the more RAM the computer has the more efficiently the soft sampler will perform.
11 - Why are Zip Drives used with some hardware samplers?
Zip drives are used for storage reasons; they can hold much more data than a floppy disk which is essential to store 24 bit audio samples, they also allow for reliable long term storage.
12 - How can a sampler be used to add a 'vinyl effect' to a song?
A sample can be made of a record playing in-between songs or the run-out grooves, picking up the crackle and hum of a record. This can then be looped and triggered from the sampler to add a vinyl effect to the song.
13 - What benefits do samplers with multiple physical outputs have?
Multiple outputs allow different samples to be affected by different effects / processors, they can be sent to different inputs on a mixer for individual panning, eq and leveling at that stage, and be recorded to separate tracks on the recorder.
14 - What are the benefits of working with mono samples over stereo samples?
Mono requires less storage and processing power. However, most new computers can handle many tracks of samples stereo audio simultaneously. Although stereo is not always necessary, especially when using sounds such as individual drum hits.
15 - What MIDI control messages can a typical sampler read?
Note On, Note Off, Velocity, Program Change, Bank Select, System messages.
16 - How can an instrument with a long sustain be created from an instrument with a short sustain using a sampler?
A loop could be created using the sustained part of the sample, this could be set up to loop as long as the key on the keyboard was held down, and the release triggered when the key is released. Alternatively the sustain section of the sample could be time-stretched.
17 - Aside from a MIDI lead, what other connections are (or can be) made from a hardware sampler?
SCSI, USB, USB 2.0, Firewire, Analog In/Out L/R, Assignable Multiple Outs, Digital In/Out, Word Clock, Headphones.
18 - How does a hardware sampler ensure that there is no latency?
Data is stored in RAM, or at least the first part of the audio, so that no latency occurs when it needs to be accessed.
19 - How can sample looping be used to save storage space?
Instead of an audio track taking up the length of the whole track, sampled audio can be triggered to play the same part but taking up much less space. For example for a drum track the only audio that would need to be stored would be single instances of each drum sound, these could be stored in a sampler and sequenced to replicate a full drum track. This technique can also be used to loop sample of audio, it does not only apply to single hits or instrument sounds.
20 - What are the main requirements of a glitch free loop?
The start and end points of the sample should both have zero-crossing points; this is easily achieved using soft-samplers which allow a zero crossing point to be selected.
21 - Why are closed and open hi-hats often sent to the same mute group?
Because if the drum samples are attempting to recreate a real drum kit then the high-hat would not sound open and closed simultaneously. Therefore when one is sounding, the other must be muted.\
22 - On hardware samplers, how much sample time would you typically get out of 64MB storage?
Frequency rate x bits per sample/8 = bytes per second.
Bytes per second x 60 = mono file size per minute in MB
2 x mono file size per minute in MB = stereo file size per minute in megabytes.
Storage space in megabytes / Megabytes per minute (mono file) = minutes of sample time
44.1 X 16 / 8 = 88.2 bytes per second
88.2 X 60 = 5.292 Megabytes per minute (mono file)
2 X 5.292 = 10.584 Megabytes per minute (mono file)
Therefore 64 / 10.584 =
6.05 minutes of sample time
23 - How might you achieve a chorus effect using a sampler that does not have an effects section?
Sample the same sound twice with one instance of the sample affected by slight pitch changes controlled by a LFO.
24 - How might you soften the start of a drum sample (single hit)?
Add a smoother attack to the sample using the samplers VCA envelope.
25 - In which phase(s) of the envelope (attack/decay/sustain/release) might you place the loop in a sample?
Sustain. |
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Fri Apr 16, 2004 10:16 pm |
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hoggs33
Joined: 09 Feb 2004
Posts: 55
Location: Nottingham, England |
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01- What are the logistical disadvantages of multisampling?
It uses up extra memory space and quite be quite a time consuming process as it involves taking several samples across and instruments range
02- What is the importance of 'zero crossing' with sampled material?
Zero crossing enables the sampled material to be played back with a click at the beginning pr end of the sample.
03 - What problems may there be with sampled material from vinyl in terms of pitch/tempo?
Vinyl can become warped or the turntable may not spin at a regular speed resulting in pitch and tempo problems.
04 - What are the benefits of multisampling?
Multisampling enables a better sound to be achieved when trying to imitate a conventional instrument. Samples should be taken every half octave or so over the full range of the instrument and assigned to keys in such a way that they will never be played back for more than a few semitones from their original pitch.
05 - What are the advantages of USB connectivity for a sampler?
It enables the sampler to be connected to a PC thus allowing sampled material to be ‘downloaded’ directly to the sampler from the PC thus making transfer of samples quicker and easier possibly with drag and drop functions.
06 - Why do some samplers offer SCSI connectivity?
To allow connection to a CD ROM drive to read sample disks or for connection to a hard drive to store sample banks.
07 - What is 'tracking'?
Tracking is used when using filters in order to offer a more realistic representation of a note at higher frequencies. In this instance the cut-off frequency of the filter has to be increased the higher the frequency of the note. The filter cut-off frequency tracks the note throughout the keyboard and this is known as tracking.
08 - Why might an LFO be used with a sample?
To alter the pitch or timbre of a sample similar to the use of an LFO on a synthesizer.
09 - What filters are commonly offered with contemporary samplers?
Low pass, Hi Pass and Band pass.
10 - How do 'soft samplers' such as Gigasampler store their samples?
The samples are stored on the computers hard disk in audio formats such as WAV or AIFF.
11 - Why are Zip Drives used with some hardware samplers?
Zip drives provide an economical way to store larger amounts of data than say floppies as sample storage takes up a lot of memory. Zip drives are also portable so can be used on other compatible samplers.
12 - How can a sampler be used to add a 'vinyl effect' to a song?
I guess by using a sample of or getting hold of a sample of the sound of vinyl turning i.e the slight click and crackle etc and then looping this to be played in the background of a track.
13 - What benefits do samplers with multiple physical outputs have?
The outputs can be put through a mixing console and so can be mixed ‘live’ and effects added etc.
14 - What are the benefits of working with mono samples over stereo samples?
Mono files use less memory and I guess may be easier to place in a mix. They would laso take up less processing time etc.
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?
By looping the sustained section of the sample or by ‘stretching’ the time of the short sustain section.
17 - Aside from a MIDI lead, what other connections are (or can be) made from a hardware sampler?
Line in and Out (possible multiple outs), USB connection, SCSI connection, now-days I would guess there would be a S/PDIF digital in and out, headphone connection.
18 - How does a hardware sampler ensure that there is no latency?
Selected samples are stored in RAM so they can be accessed without any delay.
19 - How can sample looping be used to save storage space?
For a recurring pattern, like a drum loop small sample loops can be stored but then used over and over again for the duration of the track on a ‘repeat’ setting thus saving memory.
20 - What are the main requirements of a glitch free loop?
Zero crossing should be used to prevent any clicks at the beginning and end, the length of the loop needs to be exact so that when it goes ‘back’ to the beginning of the loop it matches the tempo of the track.
21 - Why are closed and open hi-hats often sent to the same mute group?
In order to ‘mimic’ a real hi-hat – the open hi-hat never plays at the same time as a closed hi-hat, so when one plays the other is muted.
22 - On hardware samplers, how much sampletime would you typically get out of 64MB storage?
1 minutes worth of mono samples at CD quality takes up 5mb of memory space. Therefore with 64 mb of storage you would get around 13 minutes of sample time. I assume this time would be halved if using stereo samples.
23 - How might you achieve a chorus effect using a sampler that does not have an effects section?
Each sample of a program should be assigned to two keygroups (or zones) and the keygroups slightly detuned
24 - How might you soften the start of a drum sample (single hit)?
Set the attack time of the envelope generator to a longer value.
25 - In which phase(s) of the envelope (attack/decay/sustain/release) might you place the loop in a sample?
Sustain or release. |
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Fri Apr 16, 2004 10:41 pm |
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iNSTiNCT2765
Joined: 05 Nov 2003
Posts: 60
Location: Denmark |
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I've uploaded the samplers practical to my folder on the ftp...haven't worked on remixing 'stuff like that' but I will tomorrow. 8O
Week 6 – Samplers 1
01 - What are the logistical disadvantages of multisampling?
Multisampling is more time consuming than just one note sampling. The more detailed and realistic you want the range of an instrument to be, the more samples will have to be recorded, which then in turn take up more memory space in a sampler.
02 - What is the importance of 'zero crossing' with sampled material?
This is important to avoid clicks in the samples. When looping a sample, if the start and end point are both at the zero line, then it is more likely to have a seamless loop without clicks.
03 - What problems may there be with sampled material from vinyl in terms of pitch/tempo?
If your record player is running on low batteries or isn’t getting enough power, the sample you’re recording may fluctuate in pitch and tempo.
04 - What are the benefits of multisampling?
The instrument that has been multisampled will sound more realistic and detailed. The sound produced won’t speed up or slow down as you move across the keyboard as it would if a single sample was used.
05 - What are the advantages of USB connectivity for a sampler?
If a sampler has a USB connection, it can interface with a computer. This is beneficial because samples can be imported and exported to and from the sampler without having to record them in. Entire programs that are saved in the sampler but are not being used can be backed up or moved to the computer to free up memory in the sampler.
06 - Why do some samplers offer SCSI connectivity?
Some samplers offer SCSI connectivity so an external hard disk, CD-ROM drive or storage medium like a ZIP drive can be connected.
07 - What is 'tracking'?
It’s a function that gives higher notes shorter envelopes and lower notes longer envelopes to give the sample more realistic characteristics.
08 - Why might an LFO be used with a sample?
An LFO can be used with a sample to manipulate the pitch and tonal characteristics.
09 - What filters are commonly offered with contemporary samplers?
Low Pass, Band Pass and High Pass filters.
10 - How do 'soft samplers' such as Gigasampler store their samples?
I don’t know about Gigasampler, but in Fruityloops, the samples are stored in folders on the computer.
11 - Why are Zip Drives used with some hardware samplers?
Zip Drives are used as storage solutions. They are not as expensive as hard disks and can be good for saving your work, archiving or backing up.
12 - How can a sampler be used to add a 'vinyl effect' to a song?
Static from a record can be recorded into the sampler and looped to give a song a vinyl feeling. Samples can also be manipulated with an LFO to give a small sense of pitch bending.
13 - What benefits do samplers with multiple physical outputs have?
Individual programs and samples can be routed to their own outputs and mixed on a console.
14 - What are the benefits of working with mono samples over stereo samples?
Mono samples take up less space. They are also easier to manipulate on old samplers that record stereo samples as two independent files. Mono samples are also easier to place in a mix and by adding effects it can sound as open as a stereo sample.
15 - What MIDI control messages can a typical sampler read?
Note On
Note Off
Bank Select
Velocity
Program Change
16 - How can an instrument with a long sustain be created from an instrument with a short sustain using a sampler?
This can be achieved by looping part of the sustain of the sample.
17 - Aside from a MIDI lead, what other connections are (or can be) made from a hardware sampler?
Main outputs and individual outputs
Analogue inputs for sampling
USB Connection
SCSI Connection
Digital In/Out
Headphone output
18 - How does a hardware sampler ensure that there is no latency?
Hardware samplers ensure no latency because all samples are loaded to the RAM memory.
19 - How can sample looping be used to save storage space?
Sample looping can help save storage space because the looping points are saved but the actual sample is still the same size even though it plays longer.
20 - What are the main requirements of a glitch free loop?
The start and end points must join at the same position on the vertical axis.
21 - Why are closed and open hi-hats often sent to the same mute group?
They are sent to the same mute group because they usually don’t play simultaneously and depending on the tempo of the song, the open hi-hat sample might not reach its end by the time the closed hi-hat plays so it is automatically muted when the closed hi-hat plays.
22 - On hardware samplers, how much sample time would you typically get out of 64MB storage?
The sample time would be 11.84 minutes in mono and half of that, 5.92 minutes, in stereo if it is done in 16-bit resolution and a sample rate of 44.1 KHz.
23 - How might you achieve a chorus effect using a sampler that does not have an effects section?
By copying a sample and then panning each hard left and right. Add a little space in front of one of the sample so there is a small delay and that gives a wide stereo image of the sample.
24 - How might you soften the start of a drum sample (single hit)?
You could soften the start of a drum sample by adding a slight attack.
25 - In which phase(s) of the envelope (attack/decay/sustain/release) might you place the loop in a sample?
The loop can be placed in the sustain phase. |
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Fri Apr 16, 2004 11:31 pm |
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