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MixPre-D bunch of questions

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Craig Alan
MixPre-D bunch of questions
on Oct 17, 2011 at 4:27:12 am

1. Is the XL-3 the proper cable to connect the MixPre-D to a mini-dv camcorder like the Canon HV40? That is a camcorder that uses a stereo 3.5mm plug?

2. Can an xlr to miniplug cable be used as an alternative for one channel only? If so what flavor of this cable do you suggest -- one channel to stereo 3.5mm plug? I have done this using the mono switch on an xlr adapter but only so so results.

3. What usb cable do you recommend to connect to USB port on Macs?

4. Should it be through a powered hub?

5. XL-CAM Camera Mount Bracket for MixPre-D -- will this secure a small camcorder like the HV40? SD picture shows a DSLR but we use camcorders. Need to sandwich the mixer between the cam and a tripod. Will tilting and panning have any negative impact on sound?

6. I can connect the MixPre-D to a 302 for 5 inputs to two channels output? What cable do you suggest for this? How does the audio tech monitor each of the 5 inputs? On the 302 you can have the LEDs monitor each input at a time or the stereo output.

7. If an xlr cable goes from mike to mixer but then an unbalanced cable connects to cam or other mixer does this make the whole run unbalanced and therefore more prone to interference?

PS been waiting for such a device for a long time. The xlr adapters I've tried add noise and are cheaply made.

PPS Been using the 302s with great results with XLR cams like Sony Z7Us and now Panasonic P2s. but haven't tried with cams that only have stereo 3.5mm plugs.

OSX 10.5.8; MacBookPro4,1 Intel Core 2 Duo 2.5 GHz MacPro4,1 2.66GHz 8 core 12gigs of ram. GPU: Nvidia Geoforce GT120 with Vram 512. OS X 10.6.x; Camcorders: Sony Z7U, Canon HV30/40, Sony vx2000/PD170; FCP 6 certified; write professionally for a variety of media; teach video production in L.A.


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Richard Crowley
Re: MixPre-D bunch of questions
on Oct 17, 2011 at 7:30:38 pm

1. Yes. The User Guide says "The Stereo Unbalanced Mic Output is designed to interface with “pro-sumer” DSLRtype cameras. The MixPre-D has an unbalanced, two-channel “hot” mic level output
on a single, locking, TA3M connector"

2. Certainly there are several viable methods of connecting the output of a MixPre-D to the 3.5mm stereo mini-phone mic input of a camcorder. How you would wire that depends on what you are trying to do.

Unable to comment on your reported results because we don't know how your cable was wired, and you don't explain what "so so" means?

3. A USB cable is a USB cable. Use one that is long enough.

4. The MixPre-D does not appear to be powered from USB, so there does not appear to be any need for a powered USB hub. Unless you need it for some OTHER equipment?

5. The XL-CAM adapter appears to be adequate for a small camcorder. You Canon HV40 is approximately the same size and mass as a D-SLR. I would think about mounting the MixPre-D "sideways" to take advantage of the longer axis along the bottom of the camcorder, however.

Panning and tilting will have no affect on the audio unless the microphone is mounted ON the camera. But that has nothing to do with the MixPre-D. And mounting a microphone ON the camera is NEVER appropriate for decent sound recording.

6. A quick review of the Sound Devices website reveals no particular way of linking the MixPre-D with the 302. If you need individual monitoring, etc. then you probably need a mixer solution with more features.

7. No. The most interference-prone part of the chain is between the microphone and the mic preamp. That is the critical part that needs to be balanced. But for very short distances and/or line-level signals, unbalanced does NOT render the entire chain unbalanced. Besides, with low-end consumer camcorders, what choice do you have?

Unable to comment on your reported results with the "xlr adapters I've tried" as you did not identify what you are talking about.

NOTE: Using a mic preamp/mixer that costs almost as much as the camcorder will NOT automatically make the recorded audio great. Whatever benefit you get from the premium mic preamps and mixer will be significantly cancelled out by the lousy mic preamps in the camcorder. You cannot by pass the ultra-cheap mic preamps in the camcorder. You are stuck with them, no matter how gold-plated the previous part of the audio chain is. Any chain (audio included) is only as good as the weakest link.

It would be rather like trying to "improve" cheap canned soup from the supermarket by serving it in a solid-gold chalice. I would strongly suggest that considering using an external recorder with XLR inputs will likely deliver audibly superior results to using a premium mic preamp with a crummy camcorder. For example the Zoom H4, etc. is popular with low-budget indie producers.

Using a computer for recording production sound is typically awkward and fiddly and typically requires a dedicated sound recordist (separate from a boom operator) with his own equipment cart.


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Ty Ford
Re: MixPre-D bunch of questions
on Oct 17, 2011 at 10:55:54 pm

Dear Richard,

Thanks so much for being such a invaluable part of the Audio Forum here at Creative Cow.

Regards,

Ty Ford

Cow Audio Forum Leader
Want better production audio?: Ty Ford's Audio Bootcamp Field Guide


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Craig Alan
Re: MixPre-D bunch of questions
on Oct 18, 2011 at 2:31:44 am

Thanks Richard,

I did some more digging on my own:

1. The MixPre-D has no TA3 mini-XLR connectors for either input or output. At least from what I can see in the online photographs.

The Mixpre-D does
have TA3 output. The cable should work.

2. Unable to comment on your reported results because we don't know how your cable was wired, and you don't explain what "so so" means?

XLR adapters I’ve used add noise to the signal and don’t provide any control of the signal and have no way to monitor the sound. They also die within a year or so of use.

4. The MixPre-D does not appear to be powered from USB, so there does not appear to be any need for a powered USB hub. Unless you need it for some OTHER equipment?

Gotcha. Thanks.

5. The XL-CAM adapter appears to be adequate for a small camcorder. You Canon HV40 is approximately the same size and mass as a D-SLR. I would think about mounting the MixPre-D "sideways" to take advantage of the longer axis along the bottom of the camcorder, however.

Thanks.

Panning and tilting will have no affect on the audio unless the microphone is mounted ON the camera. But that has nothing to do with the MixPre-D. And mounting a microphone ON the camera is NEVER appropriate for decent sound recording.

No intention of camera mounting mike. My concern was that the wire from the mixpre to the camcorder would be pulled back and forth by tilting and panning. The miniplugs on these cams are fragile, the connection less than solid. But I guess some Velcro or gaffer’s tape for support will do the trick.

6. A quick review of the Sound Devices website reveals no particular way of linking the MixPre-D with the 302. If you need individual monitoring, etc. then you probably need a mixer solution with more features.

Actually the same TA3 will connect to the 302. There is an option on the 302 that allows for isolating each input. It will work if a bit of a learning curve.

7. No. The most interference-prone part of the chain is between the microphone and the mic preamp. That is the critical part that needs to be balanced.

Thanks!

NOTE: Using a mic preamp/mixer that costs almost as much as the camcorder will NOT automatically make the recorded audio great. Whatever benefit you get from the premium mic preamps and mixer will be significantly cancelled out by the lousy mic preamps in the camcorder. You cannot by pass the ultra-cheap mic preamps in the camcorder. You are stuck with them, no matter how gold-plated the previous part of the audio chain is. Any chain (audio included) is only as good as the weakest link.

While I agree for the most part that these cams are not capable of really good audio I do not agree that a good mixer and mikes do not significantly improve the recorded sound. By preamping the sound and controlling the levels the preamp of the camcorder can be kept at lower levels and therefore introduces less noise and distortion. Also being able to monitor the incoming signal you get better results. For this class of camcorder the HV40 has decent sound and some manual control. I agree that a separate recorder will do better. But these are for beginning students. Will use better gear for more advanced projects.

It would be rather like trying to "improve" cheap canned soup from the supermarket by serving it in a solid-gold chalice.

I would think it would be more akin to adding some chopped onions, olive oil, and fresh garlic to a supermarket tomato sauce. Or playing a really well recorded CD on an inexpensive stereo system.

However, we’ll see. I need some way to get XLR corded mikes hooked up to these cams. If the sound is still crap then down the road we’ll add recorders and sync in post. But by then maybe we’ll add better cams even for the beginners.

I had one class once where we had each team on Sony pd170s. The Sony’s had really bad sound for a prosumer cam. Mixers helped a lot.

Using a computer for recording production sound is typically awkward and fiddly and typically requires a dedicated sound recordist (separate from a boom operator) with his own equipment cart.

I’m not interested for the most part in using a computer for production sound but rather for voiceovers and post work. For higher end production we will be shooting with the 302s, Sony Z7Us and Pana P2 cams connected to a Ki Pro which records very nice sound but does not have particularly good meters.

OSX 10.5.8; MacBookPro4,1 Intel Core 2 Duo 2.5 GHz MacPro4,1 2.66GHz 8 core 12gigs of ram. GPU: Nvidia Geoforce GT120 with Vram 512. OS X 10.6.x; Camcorders: Sony Z7U, Canon HV30/40, Sony vx2000/PD170; FCP 6 certified; write professionally for a variety of media; teach video production in L.A.


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Ty Ford
Re: MixPre-D bunch of questions
on Oct 18, 2011 at 11:18:35 am

Craig, I think Richard is right about improving the sound if the problem is bad audio input design. Regardless, here's my review from TV Technology. Not a bad trade mag, btw.

Sound Devices MixPre-D
Two Channel Mixer with Analog, Digital and USB Outputs
Ty Ford

In the field, in the studio or in post, there are times when you don’t need or don’t want a big audio mixer. Maybe you’ll only be working with a mono or stereo source, but you want something better than camera microphone inputs. In some cases, the devices you’re asked to feed have no reliable balanced, analog audio inputs; computers, iPhones, iPod touch or iPads.

If you find yourself in these situations enough times to do something about it, try the Sound Devices MixPre-D (D for digital). It’s like the analog MixPre because they share a nearly identical front end, but the MixPre-D has 24-bit AES3 and USB outputs. There are some other differences, no input peak lights on the MixPre-D and many of the dedicated external switches on the Mix-Pre have been internalized on the MixPre-D, requiring “hold this, slide or twist that” operation of the remaining buttons, knobs and switches.

For example, to switch sample rates, you need to hold down the headphone level control and switch the left XLR output switch to the AES position. Not a deal killer, but you’ll want to acquaint yourself with the operations manual. Fortunately, Sound Devices printed the info on the MixPre-D bottom panel. You do need to be a little careful about grabbing the MixPre-D because you might inadvertently hit a button that does something you don’t want it to do at that moment.

On the input side, the two 2k Ohm impedance XLR analog mic/line inputs are transformer balanced with 66 dB gain and a very quiet -128 dBu EIN. Plenty of gain, even for a Sennheiser 421 dynamic mic. Line input impedance is rated at 16k Ohm. Input clipping of the mic circuit doesn’t happen until -10 dBu and +28dBu for line input. Common Mode Rejection Ratio is 100 dB at 80 Hz, 60 dB minimum at 10 kHz. Frequency response is 20 Hz - 30 kHz, +.2 dB / -.5 dB.

Need more than two inputs? If you don’t need stereo headphone return monitoring, each channel of the Tape Return input can be independently routed to the left, center or right output busses. Those sources need to be -10 or line level and adjustable, because the Tape Return input has no mic preamps. Input levels for inputs 3 and 4 are controlled by pressing input 1 and input 2 buttons and turning the headphone control.

The MixPre-D’s has five different stereo outputs; an active-balanced mic/line via two XLRs, an unbalanced, fixed 200 Ohm mic level via TA3M for DSLR cameras (-36 dBu), an unbalanced, fixed 2k Ohm Tape Out via 1/8” TRS, a 24-bit AES3 XLR and a 24-bit USB (cable included). The MixPre-D’s 24-bit A/D converters operate at 44.1 kHz, 48 kHz, 96 kHz, and can be switched at the mixer or from the Apple Audio/MIDI Setup panel after connecting to a Mac. When I connected to my Mac via USB, the MixPre-D automatically detected that the Apple Audio/MIDI panel was set to 48 kHz and switched to 48 kHz. The USB interface works with Apple 10.4+, Windows Vista, Windows 7 (32- and 64-bit) or Linux.


There’s a 2-way switch on the MixPre-D left XLR out for mic/line switching. The right XLR output has a 3-way, for mic, line and AES3. In AES3 mode, the left XLR output continues to pass analog audio as long as either of the inputs are panned to left or center. When using the AES3 mode, the right XLR passes signal from both inputs regardless of panning. So you can have simultaneous analog and digital outputs, but the analog XLR output will not be in stereo.You can still get stereo analog out via the unbalanced Mic and Tape level outputs. Both left and right USB output also remain active in AES3 output mode. Remember to turn down any input pot not being used to keep the unterminated XLR noise from getting to the outputs.

The MixPre-D supports X/Y and M/S stereo linking and in those modes the high pass filters and limiters continue to work. In X/Y, the channel two pot controls both preamp levels. You can also reassign the inputs to different or both outputs with the output pan switches. During M/S operation, with the mid mic in input one and the bi-directional mic in input two, input one controls the spread and input two controls the overall gain.

The input and output limiters have an adjustable threshold from + 6 dBu to + 18 dBu. The ratio is fixed at 20:1. The attack time is set at 1 mSec with a 500 mSec release time. That’s fast enough for most program material, but sound with very quick transients, like handclaps, may sneak though. The limiters can be set to work jointly as a stereo limiter or independently, such as you might do with a different wireless mic coming in to each input.

The Mix-Pre-D runs on two AA batteries for about four hours if Phantom Power is used, but you can also run it from a 10-18 V DC external supply. Sound Devices also sells the
XL-WPH3 AC to DC power supply. An internal poly fuse protects the mixer and resets automatically after an offending power source is used and removed. You can toggle between internal and external power without interrupting signal flow. When the power drops below a certain level, the green power light flashes.

Even when the flashing light indicated it was time to replace the batteries, with two power hungry Schoeps mics attached and the headphones turned up fairly high, the power supply kept on going without motorboating. A slate mic and builtin 1 kHz tone oscillator round out the package. When slate mic or tone is activated, program is muted. Tone is sent to all outputs. The main metering doesn’t have all of the options on larger format Sound Devices mixers, but VU plus peak works fine for me and the brightness can be adjusted.

During its stay here, I used the MixPre-D to feed analog camera inputs, Garage Band, Adobe Audition CS5.5 on my Mac via USB and from the AES3 output to my Pro Tools Digi 003R. I used a Graham-Patten Systems baluns at the AES output of the MixPre-D and fed the Digi 003R via the S/PDIF input. Although recording voice happened without incident, when I engaged the tone on the MixPre-D I heard cyclical ticking within the tone at the Digi 003R. It was a clock disagreement. As soon as I changed the Digi 003R clock source from my external RME A/D converter to the S/PDIF input, everything was fine.

IN CONCLUSION
The MixPre-D appears to be another piece of good gear in the consistent Sound Devices line. I would have liked more dedicated controls so I don’t have to use various secret handshakes to change settings, but the box works very well. The Sound Devices limiters are nicely set for most program material. If your present chain doesn’t have a good set of stereo limiters, consider using the MixPre-D just for its limiters before your final record destination or PA. Last but not least, Sound Devices offers the very handy XL-CAM accessory mount that allows the MixPre-D to be securely mounted to the bottom of DSLR cameras. There’s also a standard threaded hole on its bottom plate to allow for different mounting options. Sound Devices also offers a variety of interconnect cables and external powering solutions.

© 2011 Technique, Inc. All rights reserved.

Ty Ford has been writing about audio for TVT sister publications Radio World and Pro Audio Review for over twenty years. Contact him at http://www.tyford.com

Sound Devices, LLC
300 Wengel Drive
P.O. Box 576
Reedsburg, Wisconsin 53959 USA
Phone: +1 (608) 524-0625
http://www.sounddevices.com/

Cow Audio Forum Leader
Want better production audio?: Ty Ford's Audio Bootcamp Field Guide


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Craig Alan
Re: MixPre-D bunch of questions
on Nov 6, 2011 at 8:05:03 pm

Thanks Ty,

Your review confirms my hopes for this unit. I need a mixer to mount under small cams for frequent projects shot in short class periods and for (no tech rehearsal) run and guns. I really think this will do the trick and even if the recorded audio is not ideal, I still think it will teach students how to listen with headphones and watch the meters to improve the recording. I agree with you that digital devices with proprietary menus systems are a pain. But you get used to them. These small cams have a bunch all by themselves. Pro cams are actually much easier to use once you need manual control. I wish there was a way to mount the 302 under them. It's been a real treat to use the 302 after struggling to a degree to get the shure's fp33's output to feed a camcorder's input.

OSX 10.5.8; MacBookPro4,1 Intel Core 2 Duo 2.5 GHz MacPro4,1 2.66GHz 8 core 12gigs of ram. GPU: Nvidia Geoforce GT120 with Vram 512. OS X 10.6.x; Camcorders: Sony Z7U, Canon HV30/40, Sony vx2000/PD170; FCP 6 certified; write professionally for a variety of media; teach video production in L.A.


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Ravian de Vries
Re: MixPre-D bunch of questions
on Dec 15, 2012 at 6:23:25 pm

Hi,

This is my first post here.
I also have question about the MixPre-D. I would like to connect a camera hop to the mixer. In this case a Sennheiser ew100 transmitter.
What would be the best output to connect to? I would like to use the ST UNBAL MIC OUTPUT (TA3-F). Is this a good option?

Thanks.


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Craig Alan
Re: MixPre-D bunch of questions
on Dec 15, 2012 at 7:37:09 pm

Connect the transmitter to the mixpre-d xlr outputs.

You can mount your mixpre-d under your camera using

http://www.bhphotovideo.com/c/product/765186-REG/Sound_Devices_XL_CAM_XL_CA....

Then use you wireless components to connect the mikes to the mixer and plug the mixer into your camera either xlr or miniplug (ta3-f).

MacPro4,1 2.66GHz 8 core 12gigs of ram. GPU: Nvidia Geoforce GT120 with Vram 512. OS X 10.6.x; Camcorders: Panasonic AG-HPX170, Sony Z7U, Canon HV30/40, Sony vx2000/PD170; FCP 6 certified; write professionally for a variety of media; teach video production in L.A.


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Ravian de Vries
Re: MixPre-D bunch of questions
on Dec 15, 2012 at 9:07:59 pm

I have my XLR outputs connected to a Zoom H4n for the main recordings. For reference I would like to add a wireless link from my mixer to the camera. What is the next best output option besides the XLR outputs? Can I use the Stereo Unbalanced Mix Output?


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Craig Alan
Re: MixPre-D bunch of questions
on Dec 15, 2012 at 10:04:55 pm

http://www.bhphotovideo.com/c/product/287409-REG/Remote_Audio_CASDT_Unbalan...

or

http://www.bhphotovideo.com/c/product/293008-REG/Sound_Devices_XL_7_XL7_TA3...

so u can use the screw down part of G3 cable

should do the trick but i would call sound devices tech support and ask them. They have been great when I had questions.

or if this does not work use the built in mike on your cam as a reference only for sync.

MacPro4,1 2.66GHz 8 core 12gigs of ram. GPU: Nvidia Geoforce GT120 with Vram 512. OS X 10.6.x; Camcorders: Panasonic AG-HPX170, Sony Z7U, Canon HV30/40, Sony vx2000/PD170; FCP 6 certified; write professionally for a variety of media; teach video production in L.A.


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Allen Cavedo
Re: MixPre-D bunch of questions
on Jul 28, 2015 at 11:33:14 pm

Your question: 6.

Can I connect the MixPre-D to a 302 for 5 inputs to two channels output? -> YES.

What cable do you suggest for this? -> Sound Devices XL-3 cable. MP-D 3.5mm TAPE OUT into 302 TA3 MIX IN.

How does the audio tech monitor each of the 5 inputs? On the 302 you can have the LEDs monitor each input at a time or the stereo output. -> You will hear the MP-D outputs on the 302 mix bus, so you will hear all 5 input channels from the 302 HP selector. You cannot solo the MP-D channels.


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