Articles, Reviews and Measurements of Audio Products

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...