questions re: stereo = balanced vs unbalanced = mono?, TS vs

Thanks. I hadn’t thought of that. Unfortunately, the documentation with my laptop is somewhat sparse, though that mini-documentation does come in multiple languages which makes it look bigger. :wink: I think I lucked out, though. I forgot that one of the USB ports is a black USB 2.0 version, and the other two are the blue 3.0 versions. I imagine that means that there are at least two USB ports and I should be able to plug one device into a USB 2.0 port & the other into a USB 3.0 port & be pretty confident that they are on two different buses. The Windows Device Manager does list a USB bluetooth module also & a bluetooth Human Interface Device, which might just mean one of the USB ports, I guess. I does also have an SD card reader, but I wouldn’t have thought something like that would go through a USB port.

Leaving the UCA-202 permanently mated to the stereo would be a sensible approach in that case.

That sounds like a very interesting concept. I wonder if it is a memory issue. I thought I saw recommendations somewhere that seemed to require pretty much memory for recording with Audacity, though I could be mistaken. If I recall, I thought that an older computer might not be able to handle it.

Is the absence of a cooling fan a limiting factor for the size & speed of the memory & CPU on a Raspberry Pi?

So I’d want to do a lot more testing (including making some long recordings) before I trusted the setup for production. The Pi only has a single USB bus, meaning it has to be shared with the mouse & keyboard so that might be the downfall of that scheme.

How hard would it be for an engineer to design a way to add a 2nd USB bus, or Bluetooth or Wi-fi interface to operate the mouse & keyboard? Maybe you could patent the design & sell specialized Audacity Pi s for the Voice Over industry. :wink:

Yeah, I had wondered about that, but assumed they must have recommended the headphones in that setup for listening to the recording after the fact.


I thought you had retired that setup because of insufficient volume.

For what it’s worth, the Recording Hacks 2009 review of portable USB interfaces did rank the X2U as their favorite of the four, with the Icycle coming in 3rd of 4. Probably the biggest thing it had going for it was that it was relatively inexpensive. It also had a decent amount of gain & was light, which could put less stress on the XLR plugs of the mic if plugged in directly, but it was also considered pretty fragile in that if you stepped on it it was probably toast.

I’ve done a bit more exploration on the concept. There are several interfaces that use IIS (aka I2s) bus on the PI rather than USB. The most promising is the “Wolfson Audio Card” Cirrus Logic Audio Card : ID 1761 : $49.95 : Adafruit Industries, Unique & fun DIY electronics and kits (for the older PIs) and the Cirrus Logic Audio card which is the same device designed to interface with the Model B+ and Model 2. However I haven’t yet decided to order one for testing.

That’s pretty slick. It sounds like the Raspberry Pi 2 will be pretty powerful per Wikipedia:

features a Broadcom BCM2836 SoC, with a quad-core ARM Cortex-A7 CPU and a VideoCore IV dual-core GPU; 1 GB of RAM with remaining specifications being similar to those of the previous generation model B+. Crucially, the Raspberry Pi 2 will retain the same US$35 price point of the model B,[19] with the US$25 model A remaining on sale.

So how would something like the Cirrus Logic Audio Card be best interfaced with a microphone for recording? Are SPDIF inputs/outputs common on interfaces? Or TRS to 3.5mm jacks?

thought you had retired that setup because of insufficient volume.

It can be set for “normal” announcing/presenting and it will work just fine. My requirements are to be able to also record in difficult environments and that it will not do. As I said earlier, I’ve never made a recording with the X2U that didn’t have the internal volume control smashed up as far as it will go. That’s dangerous. I can’t show up at a field recording and tell the executive producer: "Sorry, I can’t make my little doobie here loud enough. You’ll all have to go home.

Further, if you’ve been reading the mail, you know that past that frying mosquitoes thing, the most frequent complaint with stand-alone MicPres is low volume. “I want to record my expressive acoustic guitar and I can’t make the blue waves tall enough.”

Yes. That’s correct.

I can drag it out and connect it again. I believe since it has internal power supply management, it has no computer or data noise at all. It’s a serious piece of equipment. You would not want to be hit in the head with one of these things.


It still sounds to me like the Cloudlifter would be a nearly perfect fix for the “too quiet” issue, at least for those that would be fixed with an additional 20 dB of clean gain, at least if the Recording Hacks Review is accurate.

It would still need a proper microphone preamp of some sort, small mixer board would probably be my recommendation. At least on paper the Wolfson/Cirrus Logic codec chip looks like it has pretty decent A/D conversion in it.

So what would be the best way to interface the mixer with the Cirrus Logic board? That board lists “Stereo Digital input and output (SPDIF)” and 3.5mm jack for Stereo Line Input for high quality audio recording or capture, and
3.5 mm jack Stereo Line Output for connection to devices such as external stereo amplifiers or powered speakers"

Neither the 3.5 mm nor the SPDIF jacks are balanced, correct? Would they still be pretty high quality for short cable runs then?

It still sounds to me like the Cloudlifter would be a nearly perfect fix for the “too quiet” issue

It does look like that, doesn’t it?

The review confirms that the unit only has 40dB of gain. An SM-58 has a “rated output” of -56dB. Broadcast standard level is +4. That’s 60dB. 40dB. 60dB. Hmmmmm.