MixPre-D as USB Interface: Full Duplex or Not?
Dear Audio Pros,
Creative Cow has been a great resource for me thus far. The tips and discussions on Final Cut, video and audio production have been very helpful.
I'm making a documentary. After trying several location audio setups I've settled, so far, on the MixPre-D, as it will give me the benefits of both direct-to-camera audio to my XH-A1 via XLR, as well as a quality line-out for backup recording.
I just received the MixPre-D, and it's really awesome... except for one thing, which may be due to my ignorance.
If I'm using the MixPre-D as a computer interface, say for voiceover work, is there a way to monitor the computer audio in the headphones while recording a voiceover track? I see that I can toggle, via the HP button, between monitoring the mics, the aux return, and the USB output... but seemingly not the USB output with mic inputs simultaneously. In other words, is the MixPre-D not a "full duplex" device?
(I also thought about just connecting the analog out from my Mac into the aux in on the MixPre-D, but that seems cumbersome, and wouldn't it wind up recording that extra audio to my voiceover track?)
This thing is perfect for location mixing, but am I wrong to think it would make sense to be able to monitor the computer mix while recording with it, since it has USB?
Thank you all for your time.
Hello Tom and welcome to the Cow Audio Forum.
Did you choose the MixPre-D as the input and output device in the apple sound control panel?
Cow Audio Forum Leader
Want better production audio?: Ty Ford's Audio Bootcamp Field Guide
Hi Ty! Thank you.
Yes, I did try that, as well as switching to 44.1k sample rate. I tried playing iTunes while having my Rode shotgun connected to input #1 on the MixPre. When I push the HP (headphone) knob, it cycles between monitoring the mic (mixer output), then the tape/aux in, then the USB output, as the manual suggests, but never any two of them at a time, unless I route the tape-in into the mix.
I've seen other discussions on the MixPre-D vs. the USBPre-2, but I gathered from these that the limitation was that the MixPre-D's USB output could only go to the headphone jack, as opposed to the balanced outputs (USBPre-2), which is fine with me.
I guess I'm asking about "hardware monitoring" more than "duplex" -- my mistake. The MixPre-D's input is received on the Mac while it is also set as the output, it's just not mixed in the headphone out.
Do you know of a way to achieve real-time monitoring on this device, or would I need the USBPre-2?
And if I did trade it, is the USBPre-2 as roadworthy as the MixPre-D? (I'm aware of the lack of internal batteries, but other than that...?)
The Sound Devices people are very nice. Call support on monday and talk to one of the guys about your thoughts.
Audio Forum Leader
Want better production audio?: Ty Ford's Audio Bootcamp Field Guide
Hi, it's true about SD support. They are very responsive and patient with any problems you might have.
Please report back on the best monitoring solution for V.O. work. This is one of the reasons I purchased the units.
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.
Hey guys, been working with Stephen at SD on this. He's been very responsive and helpful. Here's what I've learned so far:
1. It is NOT possible to hear the USB output and the mic input on the MixPre-D at the same time. That means -- no zero latency monitoring. Even aux analog out from the computer will not work, as you cannot hear the aux (tape) in and the mic in on the MixPre-D at the same time. Ugh.
The only solution would be (a) software monitoring, or (b) using the MixPre-D as the preamp in front of a different computer interface that would provide hardware monitoring. Not elegant, but for now, I can live with this. I'll just have to use my RME FireFace 800 (which I wanted to sell) as the interface if I need that.
2. In regards to the tape outs -- since I want to record directly to camera (XH-A1) with a digital audio backup, I like the MixPre-D's "plug and go" way of working -- that is, no level fumbling on the outputs. Stephen said -- "With the Pre2, you would have to find your unity setting so that it passes the mic inputs through the outputs without applying attenuation or gain. This flexibility is nice, but anything coming out of the AUX outs will need to first be processed through a computer unless being used in stand alone mode." In other words, apparently I couldn't drop the Pre2 in my bag and start a shoot without "checking and double checking" it. OTOH, with the MixPre-D, just plug stuff in, turn it on, and the only level to deal with is the preamp level -- nice.
3. I did a sync test with the Sony PCM-M10, which is getting a love fest on TapersSection. Yes, it's line input, though not that sturdy, is very low noise. However, its digital clock is, like, "What the heck? Sony! Dudes! Where did you get the digital clock for the M10... from a cheap cell phone?!" Much cheaper recorders can have a more accurate digital clock than this thing. Here's what I did:
a. Rode NTG-3 into the MixPre-D;
b. MixPre-D into the Mac / Soundtrack Pro via USB;
c. MixPre-D tape out to the Sony M10;
d. MixPre-D XLR out to the XH-A1.
I recorded for over an hour straight onto a 63-minute tape. I found that the MixPre-D's digital clock (via USB into Soundtrack) kept very close time with the XH-A1 -- only a frame or two difference over an entire hour!!! However, the M10 quite noticeably lost sync after less than 10 minutes. Thus, I decided to order a Marantz PMD-661 because of its digital input, which will sync with the MixPre-D, which, IMHO, has a very good digital clock.
Here's the killer question(s):
Now that I'll be recording digitally, and thus won't really need the 1kHz reference tone, and picking up extra "bulk" with the larger PMD-661 chassis to boot, should I look again at the USBPre2? Am I wrong that it is not a "plug and go" device like the MixPre-D? Has anyone used the USBPre2 as a field preamp / "mixer" (not really a mixer, but...) for film sound, running the Pre2 into both a digital recorder and a camera?
Does the USBPre2's clock line up nicely with video like the MixPre-D's?
Or should I just stick with the MixPre-D?
Thanks again guys.
I really like the MixPre-D alot, I bought it in the hope I could use it for both field use and desktop, it replaced a Duet2 which I wasn't overly impressed with (preferred duet1) but that'ls another .. boring story.
For field use I'm lost without the mix pre-d but with my mac while it's great at a lot of things it has a few limitations and not being able to play a USB keyboard and sing into a mic plugged into the D is a bit of a shame.
I guess I'll probably buy a USBPRE2 aswell, I'm new to the sound devices world, it is heaven.