MEASUREMENTS: Topping HS01 - USB 2.0 Isolator & Ground Loop Eliminator (and a listen to Santana's "Blessings and Miracles")

Hey everyone, as you might be aware, I'm not a fan of USB "doohickeys" in general use. You know, all those USB boxes that are supposed to clean up your signal, or maybe reduce jitter, or "regenerate" this and that. Especially if you're not sure if you actually need it; some of these devices cost hundreds of dollars. On the lower price end, I had a look at the AudioQuest JitterBug FMJ last year which was a rather disappointing product.

Having said this, there are devices that can provide benefits like USB isolation for things like DACs. For example, the USB1 inexpensive ADuM4160 devices like this Nobsound ADuM4160. The problem is that this is only operating up to USB1 12Mbps "full speed". Furthermore, one would be limited to 24/96 performance even if the device is able to fall back and negotiate as USB Audio Class 1.

Enter the Topping HS01 (~US$70), a little black metal USB2.0 box advertised as providing galvanic isolation (to 1kVrms), for data and power lines with USB-B (to computer), and USB-A (to audio device) ends. Furthermore, there's a USB-C plug for devices that need extra power.

[Note: This device is not compatible with USB1.0/1.1. So don't be plugging in keyboards and mice to this. Non-audio devices like USB2 memory sticks and even my smart phone were fine. I have not tried plugging a USB2 hub up to this point so there might be issues there.]

MEASUREMENTS: Etymotic ER-4B - "Classic" In-Ear Monitor (IEM) / "Canalphone".

Nice box with accessories. Can't see it well in this picture but in the middle of the box is a small container of "damper"/"filters" and tool to aid in replacement when clogged.

Today, I want to expand the measurements of headphone-type devices to include examination of in-ear monitors. As usual, before posting measurements on a range of devices, I believe it's important to set the ground work as to how it's being done and to what relative "standard". I believe this is useful because when I use subjective descriptions, I think it's always nice to refer to context on the objective side. I have seen numerous reviews use things like star ratings or sometimes seemingly arbitrary "3.5/5"-type scores, but without more concrete, specific examples, often the reader is left without a sense of actually what is being described nor have a "hat to hang on to" when talking about relative differences with another product the reviewer might also be pointing to.

Similar to the AKG K371 back in April 2021 as a discussion of headphone measurements for circumaural (and supraaural) devices, today, I want to focus on one of the first IEM-type (In-Ear Monitor, also called "canalphone") transducers I bought back in the early 2000's. This is the classic noise-isolating Etymotic (often stylized as Etymōtic) ER-4B microPro Earphone. The very first ER-4 came out in 1991 and I believe the 4B version I have is reflective of the intent of that very first design.

While this specific ER-4B model has been discontinued for awhile now since early 2010s, there are still a number of ER-4 series products out there including the ER-4XR ("eXtended Response" meant for "music lovers" who want a bit more bass) and ER-4SR ("Studio Reference" for flatter frequency response). 

As suggested by the variants, Etymōtic makes these earphones for different target uses over the years. This '4B' model was meant for technically accurate "Binaural" monitoring purposes. Etymotic aimed for a flat response that follows a "diffuse field" target (great discussion here on the different targets BTW). 

As We Hear It: Quis custodiet ipsos custodes (by T. S. Gnu)

Quis custodiet ipsos custodes?

By T. S. Gnu

The value of articles in a magazine covering a given field lies in the new information (or well-presented summary of old information) that it conveys to the reader. The columnist watches the industry for new ideas and technologies, improvements to older technology, trends that may be worth keeping an eye on for better (e.g. the availability of ever better audio equipment at lower price points) or worse (e.g. the ever-increasing dynamic compression in recorded releases), and then cogently presents these to the reader. In light of recent positions that have been taken up both in columns and editorials, it behooves one to ask: Who Watches the Watchers?

The default stance that we see is often that these people have been in the business for a while and are, therefore, experts whose opinions must carry the weight of that expertise. In order for our stalwart writers in the audio press to be considered experts, they need to have carried out some research in the area that they are claiming expertise; mere experiential anecdotes do not fulfill this requirement. Even if one were to acknowledge their self-professed expertise/authority, there is a requirement — a duty even — to question the content of their statements before the statements can be taken seriously.