Share DP24/32 Equipment Related Tips

Discussion in '2488 and DP-24/32 Digital Portastudios' started by cmaffia, Jan 7, 2019.

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  1. Mark Richards

    Mark Richards Well-Known Member

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    DP-24, vintage 40-4
    Update: January 06, 2020:

    Western Digital has acquired Sandisk. The following links are no longer valid.

    Please check this link for information about the Sandisk Extreme PRO series of SD cards.
    -----------------------------------------------------------------------------------------

    HOW TO READ A SANDISK PRODUCT NUMBER


    Product / Size / Sales Region & Packaging Type
    According to the SanDisk website, these are all the same product:
    US.............SDSDXXG-032G-ANCIN
    Global.......SDSDXXG-032G-GN4IN
    China........SDSDXXG-032G-ZN4IN
    Australia...SDSDXPA-032G-Q46
    Canada......SDSDXXG-032G-CNCIN
    ( https://www.sandisk.com/home/memory-cards/sd-cards/extremepro-sd-uhs-i )
    (scroll down the screen and click on "Product Numbers")

    Amazon's sales region & packaging code also might be different, but what matters are the first two segments.

    The V30 means:
    4K UHD-READY With UHS Video Speed Class 30 (V30)
    ---Capacity: 32 GB
    ---Read Speed: up to 95 MB/s (1)
    ---Write Speed: up to 90 MB/s (1)
    ---Video Speed: C10, U3, V30
    (1) Full HD (1920x1080) and 4K UHD (3840 x 2160) video support may vary based upon host device, file attributes and other factors. See: www.sandisk.com/HD

    The SDSDXXG (HC I 3/10) is 4k UHD video ready (V30):
    sdsdxxg32.jpg

    The SDSDXPA (HC I 3/10) is not:
    sdsdxpa32.jpg

    The SDSDXPA is on the most current "TASCAM Approved" list:
    http://www.tascamforums.com/threads/share-dp24-32-equipment-related-tips.5817/page-2#post-29998

    The SDSDXXG featured in this post is an update of the previously approved SDSDXPA SD card shown above and has had no known issues since the date of this post.
    Last edited by a moderator: Jan 6, 2020
    Sam Trenholme, Phil Tipping and -mjk- like this.
  2. Mark Richards

    Mark Richards Well-Known Member

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    DP-24, vintage 40-4
    UNDERSTANDING dBu & dBFS IN THE RECORDING AND MIXING PROCESSES
    dBu, dBv, and dBV are power ratings. They are commonly used for audio equipment as a measure of the voltage (power level) a particular electrical circuit can receive or send without distorting.

    dBu is an Analog Measurement.
    Zero dBu (0 dBu) and Zero dBv (0 dBv) are in reference to .775 volts (i.e., 0 dBu / 0dBv = .775 volts). Zero dBV (0 dBV) is referenced to a different voltage level: 1.00 volt, and is not relevant to this discussion.

    The pro audio (studio) standard is +4 dBu = 1.228 volts.
    The home recording level standard is -7.78 dBu = 0.3162 volts.

    Plus 2 dBu (+2 dBu) = 1.000 volt. If you look at the DP-24/32/SD Level Diagram in the OM, on the Mic circuit, a +2 dBu Mic input level produces a 0 dBFS level after A/D conversion to digital.

    The Decibel is an Analog Measurement.
    The decibel is a logarithmic measure. A sound with an intensity that is twice that of a reference sound corresponds to an increase of little more than 3 decibels. In common practice, the reference point of 0 decibels is the minimum threshold of hearing.

    A decibel is just an analog ratio that represents the relationship of two analog sounds. A decibel has no intrinsic value. Doubling the sound level produces a 3dB logarithmic change of the second sound in relation to the first, regardless of what the actual first sound level is. Because the decibel is logarithmic, there is no linear correlation between voltage and decibels.

    dBFS is a Digital Measurement.
    dBFS is "Decibels Relative to Full Scale". Full Scale is only relevant in the digital world. It is the point beyond which there is nothing but distortion when converted back to analog. For D/A conversion purposes, in the digital domain everything is 0 dBFS or less; there's no such thing as +3 dBFS.

    The Track Fader is a digital device and functions within the digital domain. Adjusting the track fader causes its digital value to range from "0" (infinity) to "127" (+6).

    There is no standard correlation/conversion of dBu to dBFS. The analog average power scale (e.g. a VU meter) is not equivalent to the digital peak scale (a dBFS meter). You can't match dBu and dBFS. dBu is volts; dBFS is a binary number.

    TEST 1
    A 1kHz .775 volt (0 dBu) signal into Line Input A of my DP-24 with the Trim Knob set to unity gain (about the 1 O'clock position) produces about -6 dBFS on the Track 1 Meter; and with the Track 1 Fader set to zero, about -6 dBFS on the Stereo Master Bus Meter with the Stereo Bus Master Fader set to 0 dBFS.

    Moving the Track 1 Fader to +6 raises the Stereo Master Bus Meter to about -1 dBFS with the Stereo Master Bus Fader set to 0 dBFS. (n.b. the Track 1 Fader has no affect on the Track 1 dBFS meter.)

    TEST 2
    A 1kHz 0.3162 volt (-7.8 dBu ) signal into Line Input A of my DP-24 with the Trim Knob set to unity gain (about the 1 O'clock position) produces about -12 dBFS on the Track 1 Meter; and with the Track 1 Fader set to zero, about -12 dBFS on the Stereo Master Bus Meter with the Stereo Master Bus Fader set to 0 dBFS.

    Moving the Track 1 Fader to +6 raises the Stereo Master Bus Meter to about -9 dBFS with the Stereo Master Bus Fader set to 0 dBFS. (n.b. the Track 1 fader has no affect on the Track 1 dBFS meter.)

    Conclusion
    Both tests demonstrate that perhaps the best practical way to look at the Fader Scale is "variance from Unity Gain".

    “0” on the Track Fader scale is Unity Gain. The incoming signal being converted A/D going to the track, and the outgoing converted D/A signal, are at the same level as shown on both the Track and Stereo Bus dBFS meters:

    • .775v in TEST 1 produces an internal digital -6 dBFS going in and coming out;
    • .3162v in TEST 2 produces an internal digital -12 dBFS going in and coming out,
    This occurs with both the Track Fader and Stereo Master Bus Fader at the 0 position.

    The Track Fader position as indicated in the Mixer screen dB scale and on the Track Scale then could be considered plus or minus so many dB relative to Unity Gain.

    Moving the Track Fader effects the cumulative digital signal going to the Stereo Bus D/A converter (either "not distorted" or "distorted" as indicated by the Stereo Master Bus dBFS meter).

    Application to Recording and Mixing
    Behind the scenes, between the A/D and D/A conversions, there are only two states: the internal digital signal processing is either "not distorted" or "distorted". So the important things to watch are the Track dBFS meters and the Stereo Bus Master dBFS meters.

    When Recording:
    (a) The Input's red distortion light should not trigger;
    (b) The Track dBFS meter should not exceed -12 dBFS to -9 dBFS; and
    (c) The red distortion light at the top of the Track dBFS meter should not trigger.

    Remember that when recording, the Track Faders are only used to set the playback level to the Stereo Master Bus for monitoring purposes. While the individual Track Faders can be set to provide the desired overall balance for monitoring purposes, the Stereo Bus Master dBFS meters should remain between -12 dBFS and -9 dBFS, and the red distortion light at the top of the Stereo Bus Master dBFS meter should not trigger. Re-balance the Track Faders if necessary to control this.

    Those with little or no prior recording experience should work at even lower dBFS levels (between -18 dBFS and -12 dBFS). It's better to have a slightly softer song than have it ruined by the unpleasant sound of digital distortion. A soft recording/mix can be raised to a louder level. A distorted song is permanently damaged.

    When Mixing:
    (a) The individual Track Faders are used to create the desired overall balance of the mix.
    (b) The Stereo Bus Master dBFS meters should remain between -12 dBFS and -9 dBFS, and
    (c) The red distortion light at the top of the Stereo Bus Master dBFS meters should not trigger.


    If the red distortion lights at the top of the Stereo Bus Master dBFS meters trigger, keep things out of the red by adjusting the relative playback positions of the individual Track Faders, not by lowering the Stereo Master Bus Fader (which should always be at 0 dBFS except for fade in/fade out so that you don't alter your primary point of reference - the Stereo Bus Master dBFS meters.)
    Last edited by a moderator: Oct 31, 2019
  3. Mark Richards

    Mark Richards Well-Known Member

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    DP-24, vintage 40-4
    TO PUT THE CAP ON SD CARD ISSUES:

    The Owner Manual is quite clear (in my case for the DP-24 on page 9, OM version D01159020F):

    "Use of SD cards that have not been verified for use with this unit could result in the unit not functioning properly."

    File Errors, write errors, unit freezes/lockups, etc. have all been traced to use of SD cards not on the TASCAM approved list, counterfeit SD cards, out-of-date firmware, or all three.

    A full format should be done for a new SD card, and when the firmware is updated (after first backing up the SD card content to a computer or other backup device). A full format will also check the TASCAM approved SD cards for physical memory errors (bad sectors).

    More on buying SD cards here (thanks to the efforts of Sam Trenholme):

    http://www.tascamforums.com/threads/sd-card-buying-hints.6017/
    Last edited: May 6, 2019
    -mjk- likes this.
  4. -mjk-

    -mjk- Moderator Staff Member

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    Hukou Township, Hsinchu County, Taiwan
    Gear:
    DP-32, | 2A Mixer, A3440
    In addition to what Mark said above:
    • Make routine backups of your Song folders, using the machine's USB function (every session).
    • Periodically backup the entire card, and do a full format. Copy the full backup to the card after. 90 days is what I do. This procedure can detect bad sectors before they become dysfunctional.
    • Copy/Paste files to/from the SD card using the machine's USB function, rather than removing the card from the machine and using a card reader.
    • Always properly disconnect the USB connection.
    Mark Richards likes this.
  5. Mark Richards

    Mark Richards Well-Known Member

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    USING OUTBOARD GEAR DURING MIXDOWN

    The easiest way to make use of an outboard FX during the Mixdown process is to use the DP-24/32/SD Inputs to receive the returns of the outboard FX and assign those DP-24/32/SD Inputs directly to the Stereo Bus.

    SETUP
    This procedure assumes you do not want to use any tracks to record the return of the outboard FX signal, but rather want to send it directly to your stereo mixdown recording.
    1. If the outboard FX gear receives a stereo signal, then the DP-24/32/SD’s Send 1 and Send 2 for each Track you want to process are used (be sure to turn off the internal effects connected to Send 1). Otherwise, Send 2 can be used for the outboard effect and Send 1 can be used for the internal effects.
    2. Set the DP-24/32/SD Track Sends to Pre-track fader or Post-track fader, depending on how you want to control the signal going to the outboard FX gear. You can also use the Track Send level and the Master Send level to adjust levels to the outboard FX according to your needs.
    3. Set the outboard FX gear’s inputs, controls, and outputs as required/needed according to the owner manual for the gear.
    4. Set the DP-24/32/SD’s Trim Knobs full left (Line) for the Input(s) receiving the outboard FX signal.
    5. Assign the DP-24/32/SD’s Input(s) that are receiving the outboard FX signal to the Stereo Bus.
    6. Assure all the DP-24/32/SD Send controls for Inputs A~H are turned off to prevent a feedback loop with the outboard FX gear.
    7. Assure no DP-24/32/SD Inputs other than those receiving the outboard FX signal return are assigned to the Stereo Bus.
    PROCESS
    1. Enter Mixdown mode.
    2. Set the DP-24/32/SD levels going to the outboard FX gear.
    3. Set the FX controls on the outboard gear as required.
    4. Set the desired effect on the outboard gear and assure it is 100% wet.
    You can control the FX return signal coming into the DP-24/32/SD stereo mix in a couple of ways:
    1. If the outboard FX gear has an output gain control, the return to the DP-24/32/SD’s Input(s) can be set at that point to control the FX level going into the DP-24/32/SD stereo mix.
    2. On the DP-24/32/SD Mixer Screen you can use the virtual fader(s) for the DP-24/32/SD Input(s) receiving the FX signal to set the level of the FX going into the DP-24/32/SD stereo mix.
    Additional information on connecting outboard gear can be read here:
    http://www.tascamforums.com/threads/share-dp24-32-equipment-related-tips.5817/#post-29576
    Last edited: May 10, 2019
    Bobbydebarbes, David Porter and -mjk- like this.
  6. Mark Richards

    Mark Richards Well-Known Member

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    DP-24, vintage 40-4
    MORE ON AUDIO DEPOT IMPORT/EXPORT

    A quick fix to identify specific tracks when non-sequential tracks are being exported and imported back:

    The Problem
    15 characters won't fit on the small screen, so although the songname + track number are captured in Audio Depot when the tracks are exported, when displayed for import, a song with a 5 character or more "songname" gets each exported track name truncated to 8 characters (e.g. "songna~1", "songna~2", etc. through "songn~32").

    So the track number information is "lost" on import if non-sequential tracks had been exported (e.g. exported Track1, Track2, Track10, & Track12 will appear on the import screen as"songna~1", "songna~2", "songna~3", "songna~4").

    If there are more than a few tracks, and they need to be placed back in their original track positions (perhaps to load into a different virtual track), the situation can become difficult at best.


    The Quick Fix
    Temporarily change the songname to one character before exporting. When finished exporting, change the songname back to what it was. When you're ready to import, the screen will then be able to show the track number that was appended on export after the one character songname: i.e. "E_TRK01; E_TRK02; E_TRK10; E_TRK12".

    A detailed discussion on using Audio Depot can be found here:
    http://www.tascamforums.com/threads/share-dp24-32-equipment-related-tips.5817/#post-29575
    Last edited: Aug 3, 2019
    -mjk- likes this.
  7. Mark Richards

    Mark Richards Well-Known Member

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    DP-24, vintage 40-4
    TROUBLESHOOTING SIGNAL FLOW

    1. Load your reset template (you've watched Phil's video tutorial, right?), then create a new song and Load it.

    2. Open the Mixer Screen and verify that all Inputs (A~H) and Tracks (1-32) settings are neutral/off/centered.

    3. Open the Effects Screen and verify all Guitar Effects and Send Effects are off and that no tracks are assigned to the Guitar Effects.

    4. Open the Dynamics Screen and verify all Input A~H Dynamic Effects are off.

    5. Open the Assign Screen and verify all Input/Track Assigns are off; no Inputs are assigned to the Stereo Bus, and for DP-32, that all Stereo Track Pairs are set to Stereo.

    6. Set all Track Faders off (i.e. lowered to infinity).

    7. Set Input A~H Trim Knobs to the 1 o'clock position (unity gain).

    8. Set Monitor Select to "Stereo".

    9. Set Headphone Level Knob to a comfortable volume (if you want to hear the test signal).

    10. Set Stereo Bus Master Fader to "0" (unity gain) and leave it there.

    This will assure you are starting from a neutral condition.

    From this point, you can trouble shoot the signal flow. Use only one Input and one track at a time.

    Example
    Working only with Input A, connect a signal source to Input A
    1 Assign Input to Stereo Bus. Observe Stereo Master Bus meter for presence of signal
    2 Unassign Input from Stereo Bus.
    3 Assign Input to Track 1
    4 Press Track 1 REC button
    5 Observe Track 1 Meter for incoming signal
    6 Raise Track 1 fader to "0" position (unity gain), sending Track 1 signal to Stereo Bus.
    7 Observe Track 1 outgoing signal to Stereo Bus on the Stereo Master Bus Meter.
    8 Turn Track 1 Fader off (all the way down)
    9 Turn Track 1 REC button off.

    Using Input A, repeat steps 3~9 for each remaining Track.

    After all Input A/Tracks 1~32 have been completed, move to the next Input and repeat until all Inputs A~H have been tested and all Tracks 1~32 have been tested.
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  8. Mark Richards

    Mark Richards Well-Known Member

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    DP-24, vintage 40-4
    UPDATING FIRMWARE

    Assuring you've installed the most current firmware is critical to the proper functioning of your Porta-studio. Outdated firmware is one of the most frequent causes of odd behavior, unstable operation, and some SD card issues.


    You have to go to the TASCAM support website to download the firmware update for installation on your portastudio:
    https://tascam.com/us/

    DP-24 and DP-32
    • The DP-24 and DP-32 are listed under the Support/Discontinued Products page.
    • Scroll down the results page until you find the DP-24 and DP-32, then click on the appropriate unit.
    • Then scroll down until you see "DOWNLOADS.
    • Click on "Firmware/Software".
    • Download the "Firmware Update Procedures" and the latest firmware.
    DP-24SD and DP-32SD
    The firmware can be found on the Support/Downloads page.

    The procedure is the same as listed above.
    All downloads need to be unzipped first.

    Instructions for updating are also in your owner manual and are very simple, clear, easy and painless. If you've misplaced your owner manual, you can download the owner manual from the same DP-24/32/SD Support sections. Look under MANUALS for the respective units.
    Last edited: May 6, 2020
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  9. Mark Richards

    Mark Richards Well-Known Member

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    DP-24, vintage 40-4
    Technical Concepts Regarding Reference Speakers:

    Professional reference speakers are "flat"/"neutral"; that is, they've been designed to reproduce the audio spectrum in an anechoic chamber to a measured 20Hz to 20kHz +/- 3 dB or better at a distance of 1 meter at a stated SPL/RMS level.

    "Musicality" is the accurate reproduction of instruments and voices; accurate reproduction of the sound stage breadth and depth (imaging); and accurate reproduction of the frequency range of each instrument/voice; all without harmonic and other distortion.

    Recording studios, and serious audiophiles, tune the listening position to compensate as much as possible for the influence of room acoustics, but with different goals in mind:

    • Audiophiles seek a room acoustics/speaker audio reproduction system balance that yields an accurate reproduction of a live performance - the "musicality" of the recording as it would be heard in a live performance venue.
    • Studios seek to retain the flat response of the speakers at the listening position so the "musicality" of the performance captured in the studio can be determined accurately during the recording/mixing/mastering process.
    Controlled studies over a number of years have determined that the "musical" frequency response of an audio reproduction system using good speakers in a good room (the audiophile's goal) has certain characteristics.

    Using 1 kHz as a 0 dB reference point, most informed/knowledgeable listeners sitting at an ideal listening position in a well tuned room equipped with good speakers playing well-recorded music desire a frequency response characterized by:

    • A mid-range that's +/- 0 dB between 100 Hz and 1 kHz
    • A low end that has a gradual rise from 100 Hz to +3 dB at 50Hz
    • A high end that has a gradual rise to between +3 and +5 dB at 3-5 kHz
    • A very high end that falls gradually from 5kHz to 0 dB again at 10 Khz and then continues dropping gradually beyond the 10 kHz/0dB point to -3 dB at 20kHz.
    (remember 20Hz - 20kHz +/- 3dB is considered a "flat" or "neutral" frequency response)
    Slight variations in frequency response in various ranges will color slightly the overall character of a speaker, making it sound "warm" / "laid back" (mild emphasis of the lower mids); or "bright" (mild emphasis of the highs); or "forward" (mild emphasis of the mids).

    None of the following speaker characteristics are suitable for monitoring, mixing, and mastering, for obvious reasons:

    • An undesirably "forward sounding" speaker will have an unnatural mid-range response vis a vis the low and high ends, either through roll-off of the low and high end frequencies; or a boost of the mid-range frequencies, or both.
    • An undesirably "laid back" or "warm" sounding speaker will have an unnatural lower mid-range response vis a vis the high end.
    • A "harsh sounding" speaker will unnaturally emphasize the high end in the 3kHz - 6kHz range, and cause listener fatigue.
    • A "muddy sounding" speaker will unnaturally emphasize frequencies below about 200 Hz.
    Here’s a link to a testing laboratory that provides objective, scientific measurement of loudspeakers:
    https://soundstagenetwork.com/index.php?option=com_content&view=article&id=16&Itemid=140


  10. Mark Richards

    Mark Richards Well-Known Member

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    Gear:
    DP-24, vintage 40-4
    USING EXTERNAL GEAR IN BOUNCE MODE

    When A Previously Recorded Track is the Source for the Outgoing Signal
    You're limited to using Send 1 and/or Send 2 Pre-fader to get a previously recorded track's signal out to the external FX gear.

    The previously recorded track's Select Button must be on (green) in Bounce Mode and that Track's Fader must be set to Infinity (all the way down).

    When A New External Signal is Being Added
    You can introduce and record a new external signal when in Bounce Mode, but it can only be added to the Bounce signal going to the mono or stereo pair track being recorded. If a stereo track pair is used for the bounce, the external incoming signal will go to both of the bounce tracks.

    In Both Cases:
    The external signal is brought in (returned) through an Input (A~H).

    The Input(s) receiving the incoming signal must be Assigned to the Stereo Bus prior to entering Bounce Mode.

    If bouncing to a stereo pair, the Input Pan Control can be used to place the incoming signal where ever you choose on the sound stage.
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