Articles, Reviews and Measurements of Audio Products

Author: our resident expert, DonH50

Wavelength vs. Frequency
Nothing special in this one, just a simple plot. When discussing distances, whether related to room interaction, comb filter effects, room treatment or whatever, there is often the assumption that bass frequencies are "everywhere" while higher frequencies can be "directed" or are "more directional". The reason for this argument has to do with wavelength -- the length of the total sonic wave at a given frequency. Like waves in the ocean, there is a certain distance from peak to peak of audio signals, and that is their wavelength. It is related to frequency; higher frequencies have shorter wavelengths. The actual equation is w = vp / f where w is the wavelength (e.g. feet), vp the propagation velocity (about 1130 ft/s for sound in dry air at sea level), and f the frequency (Hz). Room modes or comb filter effects happen when sound waves bounce off walls or interact with other surfaces, or even arrive...

This video starts slow but then picks up steam and covers a lot of fundamental problems of designing speakers and how KEF solved them in their Uni-Q drivers.

Definitely worth a watch even if you are not interested in KEF speakers.

This is a measurement of Total DAC D1 USB cable and filter. Member dallasjustice loaned this to me last year and it has been waiting for the right setup for me to test it. Now that I have that (see https://www.audiosciencereview.com/...s/do-usb-audio-cables-make-a-difference.1887/), I figured it was time to measure this cable.

This is a normal looking USB cable going in and out of a metal box that is about 2 inches long and 1.5 inch wide and 1 inch deep.


The one I have is gray and has no markings whatsoever. But otherwise looks the same, sans the extra length of the one I have. I estimate it to be around 2 meters/6 feet which their web site says retails for 360 euros. ex-VAT. That is about $428 at today's exchange rate. So not cheap at all.

The setup is as with the other thread with Sonore microRendu as the source (networked) player and the DAC, Schiit Modi 2. Here is a comparison of against generic long USB cable...

Aftermarket USB cables seem to be all the rage with people paying as much as $15,000 for a short run of it!!! Lots of subjective performance reports are out there but none back with any objective measurements that demonstrates any difference. On the other side of the fence many believe there isn't or can't be any difference in USB cables ("they are all digital"). I thought it would be good to add some data to the conversation.

For my testing, I used the Sonore microRendu as my source host. This is a networked audio renderer and comes with improved USB implementation. See my review and measureents of the 1.4 version here: https://audiosciencereview.com/foru...-measurements-of-sonore-microrendu-v1-4.1867/

For DAC, I used our perennial favorite, the Schiit Modi 2 DAC. Of course I say that in jest as this is by far the worst DAC I have tested. It seems to be highly sensitive to power and USB conditions. I figured if there is one...

This is a review measurement of an Ethernet isolator cable (passive) which is sold to medical industry. Ethernet is normally an isolated interface with transformers at both end. Addition of this is likely for high voltage surges and such.

I was loaned one of these to test. As you see, it is a simple, in-line cable: http://www.emosystems.com/product/en-60kds/


The unit retails for $204 in US and about 153 euros.

Searching on CA forum, seems like folks advocate its use to get rid of leakage noise. So I used the Sonore microRendu networked audio adapter which seems to be pretty sensitive to AC mains leakage. To make sure it didn't contribute any, I used my lap supply to power the microRendu.

The Ethernet connection is from my local lab switch which in turn connects to another larger switch in basement equipment closet. The cable from switch is about 6 feet. The isolator was placed at the end of the cable and terminating into...

Last year I reviewed the original version of networked audio streamer, Sonore microRendu. Recently someone offered to loan me the newest version 1.4 to test and measure. So here are the results.

Functionality:
The Sonore microRendu is a super light, tiny aluminum box, requiring external power to operate. The device is too light to support the weight of the cables attached to it and runs super hot. I don't recall the original version running this warm. I can barely keep my hand on it for a few seconds.

The microRendu comes with support for Roon which is the way I tested it. For external power, I tested it with iFi iPower power supply ($50), UpTone LPS-1 and my Lab Power supply.

Roon recognized the device after a minute of so of being powered on and reliability was good.

So as a way to network a DAC and remotely using it from your computer or NAS device, it works fine.

Retail price is $650 which is quite high. You can easily buy a computer for the same price...

This is a follow up to my review and measurements of SOtM SMS-200 Networked Audio Player: http://www.audiosciencereview.com/f...w-of-sotm-sms-200-network-player-part-1.1846/

Here, I am tearing down the box and showing the guts. Hope you enjoy .

The unit is rather small but pretty heft. The shroud is a heavy gauge anodized aluminum which gives me no doubt about its ability to dissipate the necessary heat. After taking off the very tight torx screws, we are greated to this beautiful sight:



As you see, it is a two-board configuration. The small board on top is the switchmode DC to DC converter (more on this later). The base board holds the microprocessor (most likely ARM based) and all the necessary peripherals.

I am a sucker for white solder mask and hence my comment about beauty. It doesn't do anything electrically but after decades of seeing green ones, it is an emotional relief.

Zooming into the power board...

Here is a measurement, teardown and review of Vinnie Rossi Ultracapacitor Power Supply. As I have explained before, this class of device aims to use a set of super capacitors as the storage reservoir to power an audio device. The idea is supposed to be to provide a mains isolated source of clean power for small audio devices and digital tweaks. This is implemented using dual capacitor banks, one of which is charging while the other powers the external device. http://www.vinnierossi.com/mini/



The unit is quite pricey in my book at $995.

The direct competitor to Vinnie Rossi Mini is the Uptone LPS-1. The Vinnie Rossi Mini includes a power supply internally while the LPS-1 does not. Uptone sells the UpTone with a switchmode power supply from MeanWell.

For this testing, I used my iFi iDAC2 USB Dac which retails for around $350. It is a popular DAC so I thought it would make a good test subject.

Since I was recently testing the Uptone...

Recently I measured the performance of UpTone ISO Regen, a device whose purpose is to clean up the USB power and signal. Alas, as shown in that review, http://www.audiosciencereview.com/f...ptone-iso-regen-review-and-measurements.1829/, the supplied MeanWell switchmode Power Supply managed to actually inject AC mains related noise which did not exist without ISO Regen.

The proprietor of UpTone, Alex Crespi while accepting the above issue, said that only 30% of their customers purchase the Iso Regen with the MeanWell Power supply. Many others apparently buy it with one of their other products, the Ultacap LPS-1.

Due to kindness of one of the owners of LPS-1, I have a unit on loan to evaluate.


The LPS-1 came without a power supply. Looking on their web site, they optionally sell the MeanWell with it. Fortunately that is the power supply I have...

Hello everyone. Courtesy of a friend of the forum , I am in possession of boatload of new hardware to measure/test. I am starting with the well regarded Mytek Brooklyn DAC measurements.



This is a $2,000 DAC with support for MQA and DSD, balanced output, and multiple inputs (Toslink, S/PDIF, AES/EBU). It even has an analog input!

The Mytek Brooklyn has a very nice OLED display, volume control, remote and headphone output. Unit is self powered with its own AC input/internal power supply. The box is the size of a paperback book, albeit in square format. It is heavy enough to feel solid and stay put.

Driver installation was a breeze and all worked the first time. For some reason I cannot get into any of the menus. The four buttons in the front that are supposed to do that, do nothing in my loaned input. Maybe there is a lock function some place.

As usual, I threw the 24-bit, 12 Khz...