Sound Devices 722,744t,Hard Disk Recorder,Compact Flash Recorder

This is a document in progress as is the 722/744t. This revision includes questions asked of Sonic Sense tnrough April 6. Sound Devices has now furthered this FAQ on their website, with further questions including ours, clients, and others. Expect regular updates and feel free to email questions to sales@sonicsense for incorporation into subsequent releases.

Written by Marc Nutter of Sonic Sense with the assistance of the kind staff at Sound Devices.

Rev 1.2 April 06, 2004.

These are the most common questions that have been asked about the Sound Devices 722 and 744t Hard Disk, Compact Flash Recorders:

722/744t:

Hard Drive:

What record times can I expect from various hard drives?

24-bit/48kHz recording requires .5gb per hour/per channel.
24-bit/96kHz recording requires 1gb per hour/per channel
24-bit/192kHz recording requires 2gb per hour/per channel

An 80-gb hard drive in a 722 could store 20 hours of Stereo 24-192kHz audio.
An 60-gb hard drive in a 722 could store 15 hours of Stereo 24-192kHz audio.
An 40-gb hard drive in a 722 could store 10 hours of Stereo 24-192kHz audio.
The stock 20-gb hard drive in a 722 can store 5 hours of Stereo 24-192kHz audio

Double the recordable time for each halving of sample rate
(ie. The stock 20-gb hard drive in a 722 can store 10 hours of Stereo 24-96kHz audio)

For a 744t, the above times must be cut in half when utilizing all four tracks.

Are there any intrinsic issues (heat, etc...) with using a higher capacity (60gb or 80gb) drive?

Storage capacity isn't as much of an issue as is hd current draw. For instance, 7200 rpm drives draw more current and generate more heat than 5400 and 4200 rpm mechanisms. Higher speed drives will have less runtime than lower speed drives. In general, the heat generating from the drive will be no more or less regardless of the hd size and capacity. The internal box temperature sensor shows internal temperature on the front panel.

Does changing the hard drive compromise the one-year warranty?

Drive replacement has no warranty implications.

What speed drives will be shipping in the 722 and 744 respectively?

Either a 4200 or 5400 rpm mechanism - depending on availability.

Will these drives support the maximum number of channels at 24/192?

Absolutely. The benefit of higher rpm drives is only a factor with transfer. There is a few percent increase in transfer speed stepping from one speed to the next.

Level Control:

Will the .5dB level control "steps" be audible in any matter other than the increased level. (ie. any clicks, pops, etc...)? Are these "steps" the same for mic and line input? How about digital input?

722 - when its inputs are in mic-level, the front panel level controls adjust the analog preamp trim level and are continuous analog trim controls - no audible artifacts. In line position they act as stepped attenuation controls, and may exhibit an audible artifact when adjustments are made during extremely quite passages (-60dB or lower). During the recording of louder material, the "tick" can not be heard.

744T - inputs 1 & 2 as above, inputs 3 & 4 are menu adjustable for attenuation level similar to line inputs 1 & 2.

For both units, there is digital attenuation at the output, but no digital attenuation at the input.

Pre-Amps:

What should we expect of the pre-amps sound quality compared to other Sound Devices products (namely the MP-2 or USBPre as many of us are familiar with them)?

The preamps on the 7-series are unique. We took advantage of the increased current available from Lion batteries and developed a preamp that is quieter, lower distortion, and far higher bandwidth than any other Sound Devices preamp. It uses a large geometry discrete transistor topology versus the transformer preamps of our field mixers.

Let's push it further, how about compared to the high-end portable pre-amps in common use?
While this is a subjective matter, what is the parting word for now until we can listen?

You can favorably compare its preamps to [the most popular field pre-amp in use], plus we exceed their specifications for distortion performance and E.I.N.

Powering:

What is the current draw of the unit given maximum operation (ie. assuming 24-bit/192kHz to HD for each the 722 and the 744t with all channels operating)? What do you estimate to be the projected battery life under these conditions with the Lithium Ion included and also with a standard 7.2 AmpHour/12V lead-acid battery?
Runtime estimates have yet to be determined based on "typical" usage, but fully loaded usage at 24/192 with four inputs, outputting timecode, writing to a 4200 rpm hd is right about 1 A (@ 7.2 V). This would mean that the internal battery may deliver 1-1.5 hours and an external lead-acid 7.2Amp Hour could easily provide 6 hours or more operating time.

You indicate that "Runtime estimates have yet to be determined based on "typical" usage, but fully loaded usage at 24/192 with four inputs, outputting timecode, writing to a 4200 rpm hd is right about 1 A (@ 7.2 V)." Where did the 7.2V issue come from?

The on-board battery is a 7.2 V Lithium Ion cell; external DC accepts 10-18 VDC. Remember that the current draw on the external DC will be higher if the on-board cell needs to be charged. The 7-Series operates just like most notebook computers--if external power is applied, it will run the unit and charge the internal (on-board) cells (if needed).

Will powering a 7-Series Recorder from a 12v lead-acid compromise the pre-amps or anything else?

Just like our mixers, there is no performance benefit from powering from higher or lower voltages. As long as the power supply (or battery) provides the necessary voltage and current, the unit's switching power supply will generate the needed voltage rails for operation. The 7-Series can take external voltages from 10-18 V (different than the mixers, which can accept voltages down to 5 V).

Can we turn off the metering display and display backlighting to save power and be less intrusive?

Yes, and to save your corneas. Brightness is fully variable; control is adjusted with the rotary encoder, just like a light dimmer. The backlight display can be on or off.

If trying to conserve power, what works best (ie. Turning off led's, using a lower sampling rate, ???)

Lowest power draw would be no phantom, no timecode output, display all the way down, lower sample rates, and writing to CF only (the hd will spin down). If you need to be super-current concious, pull the hard drive. On power up the drive always spins up for verification. If you pull it, you save that 5 watts of spin up draw.

What is the function of the C.Link ports?

The C. Link port is to interconnect two or more 7-Series recorders, both 722 and 744t, for additional recording tracks. One will become the master and subsequent units the "slave." C-Link will pass word clock to lock all units together.

Is there a "hold" feature on the transport controls? We sure don't want to have any accidents in the field.

There is a transport Lock Out for safe operation.

744t:

When recording 4-channels, will the inputs be assignable to whichever tracks we would like to record to?

Yes. This is a huge benefit and is indicated by 16 front-panel blue LED's. Any input can be assigned to any record track. The user menu is quite easy and fast to route inputs to tracks.

When playing back a four channel recording, will we only be able to monitor two channels from the analog outputs or is there a provision for mixing all channels to outputs?

Only two analog outputs are present at both analog master and headphone outputs. The routing of inputs and tracks to these is very flexible, so you can sum tracks to monitor all of them.

Will there be at least 100mS of delay available on at least two tracks?

There is selectable microsecond delay for each of the four inputs, not on tracks. Any offset will be recorded, so it may prove to be a source of user-induced error if someone applies it incorrectly.

Can the delay be changed in the 744t after recording?

Delay is printed to the file, however, most multitrack DAW's (Digital Audio Workstations) allow slipping tracks. You would want to know what delay was applied in order to accurately undo it, unless there is some sort of slate to align tracks.