Articles, Reviews and Measurements of Audio Products

This is a review and detailed measurements of the Natural Sound (NS) Audio NS17 speaker. It was sent to me by their distributor, Aoshida Audio and costs US $2,300.

These speakers are designed and built in China. The latter is not unusual but the former is. The selection of finish and material on this sample seems first class:



You can see the gloss finished veneer better from the back:



The picture does not do it justice as far as the luxury feel it imparts. Alas, as you may be able to see, there is chip around the port which has been patched. And there is a foggy spot on the top left of the speaker. Don't know if this is limited to my sample or general defects/lack of quality control in building them.

To be honest, my first reaction when I was approached to test the NS17 was to say no. Figured they are mimicking the look of a high-end speaker but...

This is a review and detailed measurements of the ifi Zen CAN balanced headphone amplifier. It is on kind loan from a member and costs US $150 from Amazon including Prime shipping.

The design is identical to new line of budget products from ifi:



No, it is not just the pictures. The silver labels on brushed metal are almost invisible. I literally had to tilt the unit, changing lighting, etc. to see what they say. I suppose you get used to it after a bit but still, should have used black ink.

The back panel is unusual in that it provides another 4.4 mm socket for balanced input:



I didn't have an adapter for that kind of use so I limited my testing to RCA in. Power is provided by a Chinese generic 2.5 amp power supply and not the usual ifi one. Cost pressure and or requirements for voltage and current must have pushed them in this direction.

From what I recall, this is a discrete implementation so will be nice to...

This is a review and detailed measurements of the Darlington Labs MM-5 Moving Magnet phono pre-amplifier. It was kindly purchased new by a member and drop shipped to me. It has a few options but as purchased, it costs US $199 from the company.

The front panel doesn't look half bad for a budget device:



The back side, not so much:



While the RCA connectors are high quality, the labeling and input power hole are as Dave Jones would say, "how you doing."

I must confess the name Darlington takes me back decades to my childhood when I was learning electronics. Darlington is a simple pairing of two transistors where their gain multiplies almost like magic. I would always have a smile on my face when I would spot it in a circuit diagram.

Here, I am not sure if any Darlington circuit is used or not. Company says it uses J-FET discrete class A amplifier with no feedback. I suspect we are going to see plenty of...

This is a review and detailed measurements of the Status Flagship ANC Noise Cancelling headphone. It was kindly sent to me by a member and costs US $179 on Amazon including Prime shipping.

I have a soft spot, pun intended, for rubberized paint that covers the Flagaship ANC:


I am not a big fan of gesture controls but that is what you have here. Voice feedback is provided for actions which helps. Turning up the volume for example requires brushing up on one of the cups.

This is a light headphone although the price for that is is rather small pads:


Note: The measurements you are about to see are made using a standardized Gras 45C. Headphone measurements by definition are approximate and variable so don't be surprised if other measurements even if performed with the same fixtures as mine, differ...

This is a review and detailed measurements of the Audio Control Rialto 600 DAC and integrated amplifier with remote control. It is on kind loan from a member and (I think) costs US $849.

NOTE: our company, Madrona Digital, is a dealer for Audio Control. Our business is custom integration of electronics and Audio Control is a regular supplier of electronics to that market. Feel free to read as much bias as you like into my commentary and review. I should add that we have had incredibly positive relationship with Audio Control with their support being first class.

This is a compact amplifier with rich set of features especially for the CI (Custom Install) market:



I was most impressed by the back side of Rialto 600 amp:



In the CI market, this amp would be buried some place that no one would see. So to have those beefy speaker terminals was a pleasant surprise. Even more so was the thought that has gone into...

This is a review and detailed measurements of the ifi hip dac combination USB DAC and portable headphone amplifier (with battery). It is on kind loan from a member and costs US $169 from Amazon including Prime shipping.

I don't know why ifi thinks this is a "hip" dac as the enclosure is a generic one offered by others:



Unusual here is inclusion of a balanced, 4.4 mm headphone jack which is nice. A bass boost function is provided which is also not present in other products.

I was surprised that I could not get the unit charged through its standard USB port but had to use USB-C:


As you see ifi continues to use male USB connection so has to provide you an adapter. Have not been a fan of its thick cable even though I understand their motivation.

Ifi Hip DAC Measurements
I started testing in balanced mode. Output was a healthy 6+ volts in high gain so I dialed that down to 4 volt and got this dashboard...

This is a review and detailed measurements of the Ikea SYMFONISK picture frame speaker designed by Sonos. I purchased it a couple of days ago from Ikea store for US $199. Their website said they had 42 in stock so they are planning to sell a lot of them. That said, there was not a single person looking at their smart home/audio booth.

There are two styles of this, one with white background and another with the same inverted so looks mostly black:

I have not looked to see how easy it is to change the fabric to something else.

There is some depth to the unit so unless you cut a hole in your wall, it will stand proud a couple of inches:



I liked the French cleat that came with it which I used to hang the speaker for measurements. Cable management is nice with that big hole where you can stuff the excess power cord. Interestingly, there is a pass through power plug so you can chain multiple while using one outlet. Smart...

This is a review and detailed measurements of the Dynaudio Core 47 professional DSP monitor (powered speaker). It was kindly purchased by a member new and drop shipped to me and costs US $ 2,499.

The Core 47 (4 inch mid-range and 7 inch woofer) comes in a PA style cabinet that is a dens as you could get:



During playback, I could barely detect any vibrations though the cabinet. The back side though -- as I have seen in other amps -- does resonate more:



Despite being DSP based, the controls are all mechanical which I like. Navigating tiny crappy menus on a lot of pro speakers can be a pain. That said, the switches don't have a good feel to them.

There are a set of switches to set the input levels and output gain. With the latter, there is some hiss in all settings and becomes especially loud at the highest setting. It was too much for me in my near-field listening (1 meter/3 to 4 feet).

The woofer and midrange...

This is a review and detailed measurements of the new Topping D10 Balanced. It was sent to me by the company and costs US $139.

The D10 Balanced as the name implies, comes in my favorite USB DAC package with the same cute orange display:



Back panel is where the difference is:



Balanced line outputs are provided using TRS (1/4 inch) jacks. These are quite common in professional world but not nearly so in consumer. Still, cables and adapters are pretty cheap and is a a small price to pay to get the benefits of balanced line output (main one being much higher immunity to ground loops).

Please note that as with the rest of the D10 family, the Toslink optical and Coax digital are outputs, not inputs! If you need them as inputs, you need to look elsewhere. Otherwise, these DACs can be used to provide digital out to other products that don't have USB input (e.g. an older DAC).

Topping D10 Balanced Measurements
You...

This is a review and detailed measurements of the Emotiva XPA-DR2 "differential" power amplifier. It is on kind loan from a member and costs US $1699 from the company direct.

This thing a beast both in size and weight:



This, despite usage of switchmode power supply to keep the "weight down." Yeh right. My back is still complaining....

There is no benefit to having a differential power amplifier but seems like they a pair of amps are used out of phase to double the power per channel:



The switchmode power supply changes supply rail on (power demand) to keep power consumption low at lower power levels ("class H"). In my testing, the DR2 barely got warm so the mechanism is working.

Emotiva XPA-DR2 Measurements
I was expecting good measurements but instead got this:



Wow, look at the harmonic spray starting at third one. SINAD of 64 dB ranks almost at the bottom of nearly 150...

This is a review and detailed measurements of the Dali Spektor 1 bookshelf speaker. It is on kind loan from a member and costs US $249 from Amazon including Prime shipping.

With the grill, the Spektor 1 looks like a $30 speaker but take it off and it has some style to it:



As soon as I took the grill off, I became concerned about all the "scratches" I thought I was seeing on the woofer. Hoped it was dust so tried to blow them off but they would not come off. Nor did they do so when I gently touched them. Later I read that the material for the cone uses wood fibers and company pictures have the same look. Kind of unsightly and makes the speaker look old so there better be technical benefits to it (core material is paper or wood pulp).

The rear port is "agricultural" as the derogatory British term for some cars go:



The only highlight is the "design and engineered by Dali in Denmark." Speakers weigh next to nothing...

This is a review and detailed measurements of the Verisonix Pro DJ N1502C hybrid electrostatic headphone (has two drivers). It was purchased new by a member and drop shipped to me. I am having a hard time finding their price. I think they sold for $120???

These don't look too bad although clearly made to seem nicer than they are:


A single slim 3.5mm cable connects the headphone to your amplifier. One channel in the headphone was dead. I could not replace the cable because the ones I have don't fit in the hole for the cable.

Note: The measurements you are about to see are made using a standardized Gras 45C. Headphone measurements by definition are approximate and variable so don't be surprised if other measurements even if performed with the same fixtures as mine, differ in end results. Protocols vary such as...

This is a review and detailed measurements of a custom Grado headphone with Elleven Acoustica R1 driver. It was kindly sent to me by a member. I don't know how much it costs. The R1 driver is 119 GBP/pair (about US $164). The gorgeous cups were made by Bruce at Wabi Sabi headphones out of cherry and mahogany.

As a woodworker, I find the overall execution simply gorgeous:



I am not going to give you the usual physical stats because this is a custom product. Wearing it, my left hear was touching the driver and this became uncomfortable after about 15 minutes. Otherwise, they are quite light and easy to wear.

Note: The measurements you are about to see are made using a standardized Gras 45C. Headphone measurements by definition are approximate and variable so don't be surprised if other measurements even if performed with...

A couple of weeks ago I post the measurements of the Monoprice THX-365IW. For that, I built a leaky back wall in an attempt to approximate the actual application. Alas, that provided such messy measurements that I thought I start over using a new methodology/system. Klippel NFS has a module for measuring drivers in a baffle. It is a combination of a special baffle and different measurements system where only the surface of the baffle is scanned. I asked for an evaluation license for the module which normally costs more than 4,000 Euros. The baffle is even more expensive so I decided to build my own. First attempts were total failures as the module assumes you have their fixture and its special alignment points. I made a second try and almost succeeded:



I say almost as the software performs an alignment check and complained...

This is a review and detailed measurements of the "The New Advent Loudspeaker" vintage speaker, circa 1977. The sample under test was kindly provided by our own @Dennis Murphy. He has looked it over and replaced a crossover capacitor to make sure it has the value it originally had. The woofer has been professionally reconed. Dennis can add more information here.

This speaker is in reasonably good shape seeing how it is made out of fragile particle board:



I didn't take a picture of the back side but there is a 3-way switch to adjust the high frequencies. Story is that this was to adjust for lack of uniformity of the recordings of the era and not to tune the speaker. I measured the difference as you will see later.

There is a site with a copy of the manual which I highly recommend to check out: https://www.theprojectasylum.com/el...adventspkrbrochure/adventspkrbrochurepg1.html

The...

This is a review and detailed measurements of the Violectric HPA V550 PRO headphone amplifier. It is was sent to me by their US distributor, Power Holdings. It costs 2,999.00EUR and US $3,399 as optioned in US.

This is one beefy, high quality execution making you feel like you are getting something for your money:



The large volume control feels nice and manages a stepped relay gain stage. Mechanically it is pretty silent. The unit comes with a remote control which adjusts the volume using its motorized mechanism. This is not needed for the headphone amp in desktop mode of course but there is an independent preamplifier with its gain control.

Speaking of gain, I am not a fan of dip switches in the back although they do provide a lot of flexibility:



There are a ton of configurations to play with here. I limited myself to XLR...

This is a review and detailed measurements of the EquiTech 1.5RQ (also called 1.5Q) Balanced Mains Power. It is on kind loan from a member and costs US $4,700.

The 1.5Q is not much to look at but boy, does it weigh a ton at 70 pounds!



The sole display either shows the incoming voltage or outgoing.


Balanced power takes a 120 volt RMS incoming feed and produces two out of phase 60 volt feeds which gives you the same differential 120 volt. This is said to do all kinds of things from reducing noise to making your music sound better. From the company:

"If you haven’t heard your sound system with a Model Q powering it, you are missing something truly great. You might just find yourself replaying all of your old music again and again as if hearing it for the first time with a new appreciation for detail, clarity and remarkable bass definition that you have never experienced before. Many of our customers have...

This is a review and detailed measurements of the ifi Zen Blue Bluetooth Receiver and DAC. It was sent to me by the company for testing months back and costs US $129 on Amazon with Prime shipping. There is now a version 2 of it. From my read of their description, it has a better antenna. Not sure what else is different.

The Zen Blue looks like the other recent ifi products:



The back side shows some interesting options:



The slide switch controls whether the output is digital or analog (can't be both). There is both coax and Toslink optical out. What is unusual is the balanced 4.4 mm that is normally reserved for headphones. Here, it is a mini balanced line out. Do not use it for headphone as it will play at full level and likely exceptionally loud!

ifi Zen Blue Measurements
From previous measurements of Bluetooth receivers, LDAC codec has shown to be most transparent. Other codecs degrade the signal...

This is a review and detailed measurements of the Japanese ZERO AUDIO Carbo Tenore ZH-DX200-CT In-ear Monitor. It is on kind loan from a member and costs US $44 from Amazon including Prime shipping. It has been around for a while and seems to have quite a following from scan of online reviews and forum discussions.

"Carbo" apparently refers to carbon fiber look (or is it real) of the body of the IEM:



As you see there is not much strain relief on the wires and what there is, is already split. People complain that the wire is thin but it is actually thicker than the ones on my Panasonic IEMs.

Note: The measurements you are about to see are made using a standardized Gras 45C. Headphone measurements by...

This is a review and detailed measurements of the Behringer NX1000D power amplifier with DSP. It is on kind loan from a member. Can't tell if it is discontinued or not but see it on sale at one place for $299. Retail cost is $549.

I am a fan of orange displays and NX1000D delivers on that (sorry my sample is not powered on):



What I am not a fan of, pun intended, is the super loud fan that stays on all the time. I walked away to go to the bathroom and was so surprised that I could hear it from very far distance in the house. Unless you can put it in a sealed cabinet, I don't see it being useful for hi-fi use. Maybe you can modify it to quiet the fan or make it temperature sensitive.

On the positive front, I really liked the look and feel of the control app that talks to it:


The only thing I did not like about it is that it is not clear when some processing is on or off. For example above, is the peak limiter on...