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Question regarding DAC & headroom of Booth on DJM900

Hi, reading more about the metering on the DJM900. I've found lots of information regarding the Master output, but nothing on the Booth output. Just to go over what I understand so far and so I'm not misunderstanding anything:

1) if your input source is DIGITAL (USB or S/PDIF) your individual channel gains cannot be clipped no matter how loud or how much you go into the red on individual channel (before it gets summed to the master output), as it maintains the digital signal in 24bit floating point on individual channels straight to the DAC.

2) However if your input is ANALOG (RCA or PHONO) you can clip the individual channels? What level of gain on input does the channel begin clipping? OVER? does each channel have +19db of headroom like the Master channel has?

3) The Master Output has +19db of headroom before it begins clipping (0dbfs). +4dB on the VU meter is 0dBU and recommended for optimal SNR?

4) The Peak Limiter is only on the Master Output. At what level of threshold does the Peak Limiter begin being triggered?

5) How does this all relate to the Booth output? if my individual channel dB on the VU meter is in OVER, but my input signal is DIGITAL, what is happening to the Booth output? If my input VU on the individual channel is +4dB on the VU meter, and my Booth knob is at FULL, what is the output signal level? How do I go about "matching" the output level of the Booth to Master?

6) Pioneer should look to adding a Attenuation option for Booth monitor as well in the Club Setup options for FOH engineers :)


Thanks for the help understanding these questions!

dsquareddan

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so...uh...I realize all the attention is going to the new DJM900nxs2, but I'd still very much like to know about these questions I asked here.

hopefully someone from Pioneer can respond. thanks

dsquareddan 0 votes
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@Dan > I'll need to get some additional input from the product team to answer specifics, but I'll do the best I can to provide some answers for you.

1) I'm sure you can still clip the input if you had the channel gain cranked all the way up, even on digital.

2) I would expect that the headroom of 19dB applies to all aspects of the signal path.

3) I always aim for the first orange LED on the channel and master strip because it's an easy visual target. On the DJM-900SRT/NXS the first orange indicates +1dB. If 0dBU is at +4, there's no harm in being slightly shy of that level either considering most track production these days doesn't take optimal signal or dynamic range into account (so many bricks!)

4) The peak limiter is relatively new and I don't have much information on its operation, other than what's in the feature statement

5) According to the manual, the output signal power for the booth is the same as the master (+8dBU), but it does not have the master attenuator or peak limiter on its path. I would then expect if your channel signal was showing 0dB on the meter, it would likely be -11dBU (based on 19dB overhead). I would match the levels by ear. ;)

6) I think you're probably the first to ask about that. lol

Pulse 0 votes
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Thanks. Hopefully you can get some answers from the product team. Just to be clear when I play I always leave headroom, but this was more for understanding when DJs I work sound for don't respect the levels

dsquareddan 0 votes
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I just tell them "Have you ever known a RED indicator light to mean anything good?" ;)

Pulse 0 votes
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Hey were you able to look into this a bit further for me Pulse?

dsquareddan 0 votes
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Sorry, I haven't heard anything back yet, I've asked for a follow-up.

Pulse 0 votes
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@Dan > Thanks for the patience while waiting to get this info, it had to go through translations for your questions, then translations again for the answers, and the office translators have been very busy recently!

Here's what they've provided:

1) Yes. If your input source is DIGITAL, your individual channel gains cannot be clipped on both of the DJM-900NXS and DJM-900NXS2. As you pointed out, the processing is floating-point DSP. DJM-900NXS2 has a CLIP indicator for each channel and MASTER OUTPUT. If your input source is DIGITAL, the CLIP indicator of each channel will not blink.

2) As for DJM-900NXS, each channel and MASTER OUT have +7dB of headroom after OVER of LEVEL METER lights up. This is the same for each channel and MASTER OUT. The status of the clipping (how much it is clipped) is not shown on the LEVEL METER. Please adjust the setting so that OVER will not light up. DJM-900NXS2 has CLIP indicator for each channel and MASTER OUTPUT. When CLIP indicator starts blinking, it warns that the level approaches clipping level. When CLIP indicator starts blinking rapidly, it means clipping has begun. Please adjust the setting so that CLIP indicator will not blink.

3) As for DJM-900NXS2, each channel and MASTER OUT have +21dB of headroom after 0dB of LEVEL METER lights up. The higher output level, the higher the S/N ratio. If the level becomes too high, however, clipping may occur at input of post-stage or internal DJM. Please adjust your DJM setting to match the input level of post-stage equipment. As for clipping occurred in internal DJM, please make sure that CLIP indicator for MASTER LEVEL METER is not blinking.

4) PEAK LIMITER can be set as MASTER OUT (XLR/RCA) and DIGITAL MASTER OUT. The trigger of PEAK LIMITER is 0 dBFS.

5) The headroom of MASTER1 OUT and BOOTH OUT is the same for both DJM-900NXS and DJM-900NXS2. OUTPUT LEVEL is almost the same if the position of VR (=variable resistance, or the knob) of MASTER1 OUT and BOOTH OUT is at the same direction (value). For example, when you preset LEVEL METER of each channel to indicate 0 dB and set MASTER VR at FULL,  MASTER LEVEL METER indicator will reach 3. When you set BOOTH VR at FULL under the same condition, the same LEVEL will output as MASTER1 when its indicator reaching 3. To match BOOTH OUTPUT LEVEL and MASTER, set the VR position to the same direction (value). However, it happens only when the ATT setting is changed to the same attenuation. In addition, PEAK LIMITER is not installed to BOOTH OUT.

6) For DJM-900NXS2, ATT change is enabled at BOOTH OUTPUT LEVEL. To use ATT, press and hold UTILITY to open [UTILITY] screen for the setting - UTILITY - BOOTH OUT - ATT.

Thank you for your inquiry. We hope this will help you.

Pulse 1 vote
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PULSE! Thank you, that is exactly what I wanted to know. Thank you so much for looking into that and getting back to me :)

dsquareddan 0 votes
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Glad that's the detail you needed. I'll pass your thanks to the engineers. :D

Pulse 0 votes
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Does the Digital Master Out on DJM-900NXS2 have ability to clip the signal, or the same as #1 applies?

Anton Tumas 0 votes
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