Файл: Eventide_H8000FW_UM.pdf

A’s outputs would be identical to its inputs: reverberant - not the sort of signal we’d normally call "dry" ! The important thing to realize is that the Wet/Dry ratio control for each DSP is relative to that DSP. It might be better thought of as a "Wet/Bypass" ratio!

The Wet to Dry ratio control for DSP B can be found on the appropriate dsp B menu page located "below" the dsp A menu page in the LEVELS area. To access the dsp B menu page,

either press the dsp A SOFT KEY a few times or press the PROCESSOR A/B key. The dsp B menu page operates just as the dsp A menu page does.

It is worth noting that the Wet/Dry controls do not operate as normal "balance controls." From 100% wet to 50% wet/dry the wet signal reduces while the dry signal is constant. The opposite applies from 50% down to 0%. This gives a more useful control function, with no 6dB dip or peak at the center setting.

Finally, we can cut the level of each output of each DSP if we so desire. This is done on the appropriate dsp A or dsp B menu pages in the LEVELS area. The dsp B menu page is located

"below" the menu page. Output levels can be cut from 0 to -100 dB. By pressing the DOWN CURSOR key to "un-gang" the parameters, individual output levels can be adjusted independently of the others.

Note: All of the parameters discussed in this section can be "remote controlled" via MIDI or the foot pedal jacks. To learn how, read:

Setting Up the External Controllers on page 92.

External Modulation and Trigger Menu Pages on page 96.

Remote Controlling Parameters on page 111.

Controlling the Level of the Analog and Digital Outputs

You can control the level of the analog outputs and the digital outputs. These adjustments are made to match the H8000FW's output levels to other equipment, and would not normally be used as level controls. You should leave these levels set at 0dB where possible in order to get the best possible audio performance.

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To adjust the level of the outputs from -100dB to 0dB, go to the output menu page in the LEVELS area. If you’re using the analog outputs on an H8000 (not an H8000A or H8000FW), Out

7 and Out 8 control the level before digital to analog conversion. Unless you have a good reason for doing otherwise, leave these at zero!

If you’re using the analog outputs on an H8000FW (not an H8000), explicit analog parameters control the level before digital to analog conversion. Again, unless you have a good reason for doing otherwise, leave these at zero!

A better place to adjust the analog output level - 90 to 3 dB is on the "bottom" outputs menu page in the LEVELS area. These adjustments are made after the digital to analog conversion. Making

your adjustments "post D/A" will generally result in lower noise and distortion than making them "pre D/A."

Note: These parameters can be "remote controlled" via MIDI or the foot pedal jacks. To learn how, read:

Setting Up the External Controllers on page 92.

External Modulation and Trigger Menu Pages on page 96.

Remote Controlling Parameters on page 111.

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system sampling rate, from wherever it is derived, or sample rate conversion must be enabled.

The digital outputs are at the system sampling rate, and all analog to digital and digital to analog conversion is done at the system sampling rate.

S/P DIF

The digital inputs 1/2 are received at either the AES/EBU 1/2 input jack or the S/P DIF 1/2 input jack. To select between the two, use the DIN 1/2 parameter on the "bottom" inputs menu page in the SETUP area.

The digital outputs 1/2 are sent out at both the AES/EBU 1/2 output jack and the S/P DIF 1/2 output jack. To select between the two formats, use the DOUT 1/2 parameter on the

"bottom" format menu page in the SETUP area. To be clear, signals will be present at both the AES/EBU 1/2 output and the S/P DIF 1/2 output, but they can only be one format. S/P DIF selects a "consumer" format while AES/EBU selects a "professional" format. Use the AES/EBU format unless you have a compelling reason to do otherwise.

Note: The digital inputs 1/2 need not be assigned to the same protocol as the digital outputs 1/2. In other words, digital inputs 1/2 can be received at the AES/EBU 1/2 input jack and digital outputs 1/2 can be sent via the S/P DIF protocol, or vice-versa.

Similarly, on the H8000FW, S/P DIF inputs 3/4 can be used in place of AES 11/12. Their protocols are fixed.

See DIN 11/12 allows the choice of either AES/EBU or S/P DIF for AES11/12. on page 61.

SAMPLING RATES

The H8000FW can operate over a range of sampling rates, from 32kHz to 100kHz. Because the higher sampling rates demand more of the signal processing resources, some large presets will not operate at the higher rates. These are identified by the absence of the "96" symbol.

If one (or two) of these large presets is loaded, the H8000FW will not allow Int 88.2 or Int 96kHz to be selected and will not lock to any digital source above 50kHz. It may be necessary

to unload both A and B presets before a higher sampling rate can be selected.

Similarly, if one of these higher clock rates is selected, or the system is locked to a digital

source above 50kHz, the H8000FW will not allow these larger programs to be loaded. 79

In effect, the H8000FW has two "speeds," a bit like gear ratios on a car. In the normal (lower) speed range, all presets can run, but only sampling rates between 32kHz and 50kHz may be used.

In the higher speed range, some presets cannot run (those which do not have the "96" symbol beside their name on the program screen (e.g., Quad*16 Grafic Eq and Stereo*32 Grafic Eq in this screen shot), but the whole sampling rate range may be used.

Note that because the ADAT protocol does not support the higher sampling rates, ADAT inputs and outputs are unusable at 88.2kHz and 96kHz on the H8000 and H8000A.

The H8000FW (but not H8000, H8000A) supports the SMUX protocol, allowing the ADAT inputs to pass four channels at 96kHz.

The System Sampling Rate – A Digital Audio Primer

All digital audio systems operate by expressing the value of the audio signal at any instant in time as a (digital) number. This number is sampled (recalculated) at regular very short intervals. The rate at which the value is sampled is known as (wait for it) the sample rate, sometimes known as a clock.

All the internal parts of the H8000FW family (including the A/D and D/A converters and the digital outputs) run at a single sample rate, known as the system sampling rate. This rate may be determined either by an internal clock, or by a single external input. If any external input is used as an audio source, it must have exactly the same sample rate as the system sampling rate, or things will get out of step, causing one or more of the digital values to be lost. This will result in clicks or distortion – a bad thing. For example, at a sample rate of 96kHz, an 0.001% difference (10 parts per million – more accurate than most clock sources) will cause a (probably faint) click about every second.

A very small difference in sample rates, as in the example above, results in slipping, meaning that the sample points “slip” past each other in time. Depending on how severe the sample rate difference is, the results may be inaudible (slight clicks will be ‘masked’ by the signal) but will be avoided by all those interested in audio quality.

Since it is unlikely that pure chance will allow any two or more external signals to have exactly the same sample rate, it is necessary to synchronize (lock) them, meaning that the external signals derive their sample rate from some common reference. This may be either a signal from the H8000FW itself, or an external signal feeding the H8000FW. It is good

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