Articles, Reviews and Measurements of Audio Products

This is a review and detailed measurements of the portable Fiio Q5s USB DAC and optional THX headphone amplifier (AM3D). It was kindly sent to me by a member. Q5s by itself costs US $300 from Amazon including Prime shipping. The AM3D THX AAA module costs an extra US $150 on Amazon including Prime shipping.

As it happens, the company was also kind enough to send one to me last year which I had yet to review! So I got a chance to test that version as well but briefly.

The form factor of Q5s is similar to other pricier stand-alone DAC/Headphone amps with chunky metal box:



There is a single micro USB connector at the bottom that provides both charging and also data connection to the PC. To use the THX module, you have to unscrew the standard one that comes with it ("AM3E") and plug in the THX one:



The volume control uses an ADC which converts is value and that is used to then adjust the level on both channels. This...

This is a review and detailed measurements of the SVS Ultra 2-way Bookshelf speaker. It is on kind loan from a local member and costs US $999 for a pair on Amazon including Prime shipping.

The sample I received has wood grain but what is on sale is glossy finish:



There are dual binding posts in the back:


There is not a lot of clearance to usncrew/screw the binding posts even for my narrow fingers.

Measurements that you are about to see were performed using the Klippel Near-field Scanner (NFS). This is a robotic measurement system that analyzes the speaker all around and is able (using advanced mathematics and dual scan) to subtract room reflections (so where I measure it doesn't matter). It also measures the speaker at close distance ("near-field") which sharply reduces the impact of room noise. Both of these factors enable...

This is a review and detailed measurements of Denon AVR-X3700H 9.2 channel 8K Home Theater AV Receiver (AVR). It is kindly loaned to me by a local member and costs US $1,199.

Visually, if you have seen one AVR, you have seen the look of the AVR-X3700H:



The input selector is plastic and while rotating it feels fine, the plastic feel is a bit jarring because you expect it to be metal. AVRs though are universally used with remote controls so this is just a minor nit.

The back panel has the typical connectors including the single new "8K" capable HDMI Input:



The 3700H is lighter than its higher end siblings which I personally appreciated as I lugged it around.

In use, the unit was quite robust, never shutting down no matter how much I pushed its amplification in my standard tests. Other AVRs can be very sensitive, constantly shutting down when pushed, often requiring a power cycle. Not here.

The 3700H does run warm and...

This is a review and detailed measurements of the XPA-700 battery operated portable DAC and balanced headphone amplifier. It is on kind loan from a member and costs US $508 including Prime shipping. It seems to be a Japan product though and not directly sold in US.

The XPA-700 is one of the most stout and rugged looking portable headphone amp I have seen. It reminds of what a field recorder would look like:



There are controls and jacks everywhere which fortunately are nicely labeled so not hard to navigate. Here is the front:



There is a balanced headphone jack in the back with the 4-pin configuration. There are options for resampling audio to higher rates (which made no difference in my testing), choice of filters, etc.

The solid feel is great for desktop use but I don't know about the merits of that in a portable product where weight matters.

USB DAC Audio Measurements
There is a micro-USB jack on the back...

This is a review and detailed measurements of the GR Research X-LS Encore DIY Kit speaker. It was kindly put together by member @Rick Sykora. You can see his build thread here: https://www.audiosciencereview.com/forum/index.php?threads/build-of-gr-research-x-ls-encore.14312/

The bare kit without cabinet costs US $249. Unfortunately they do not sell the cabinet parts so you have to source that elsewhere or build it yourself as Rick did. As supplied, this is one heavy, dense bookshelf speaker due to use of thick MDF for cabinet construction:



The back panel shows the somewhat utilitarian binding posts and the port:



This is also quite a deep speaker so don't think about using it on the desktop. I evaluated it as a hi-fi speaker in far field.

Measurements that you are about to see were performed using the...

This is a review and detailed measurements of the Advent Model 300 Vintage Receiver. It is on kind loan from a member. I believe it came out in 1970s. The original cost was US $270. That would be $1,300 if adjusted for inflation.

I love the tuner knob on the 300, reminding me of what you would find in a HAM radio:



There is no detent on various tone adjustments and balance. The slide switches are par for the era but don't feel nearly as nice of Japanese gear of the time.

The back side is decidedly cheap:



Those tiny speaker screw terminals were on the cheapest 8-track tape/receivers, not on serious hi-fi. The RCA terminals all look tired but work.

Receiver Audio Measurements
I opted to use the Aux input for my testing. I used an RCA cable to feed the pre-amp to power amp. Not sure if they came with a special shorting connector or not. Let's feed a 1 kHz tone to the 300 and see what comes out...

This is a review and detailed measurements of the BIC Venturi DV62si bookshelf speaker. It is on kind loan from a local member and costs US $120 including free shipping on Amazon (for a pair). So definitely in the extreme budget category.

You certainly are not going to be impressed with fit and finish of this speaker:



There are reports of people getting the speaker with the tweeter rattling inside as it is glued apparently!

The woofer is large (good for bass) but with no waveguide and tweeter distanced from it, it is likely going to have directivity errors (direct sound not matching reflected ones).

The back panel is definitely utilitarian but does the job:



Peaking inside the port, there is no stuffing that I can see.

There are 429 ratings on Amazon with average of 4.5 with most raving about its sound. There are a few people with two stars though which complain about harsh highs that get to you after short...

This is a review and detailed measurements of the Denon AVR-X6700H "8k" 11.2 channel Audio/Video Receiver. It is kindly loaned to me by a local member and costs US $2,499 on Amazon with free shipping.

AVRs look the same these days and the AVR-X6700H is no exception:



Inside though, is quite full as indicate by large number of amplifications with speaker terminals in the back:



I did not invoke the ECO mode. Without it, the unit runs quite warm. Some instrumentation on this later.

I tested the 6700H a couple of weeks ago and found what I considered performance issues. I ran the subset of those measurements by Denon. They examined them and confirmed that the measurements are correct for the unit I have and is due to capacitor substitution. They provided me with this statement to share with you:

“Denon is pleased to work with ASR once again, who kindly shared his Denon AVR-X6700H measurement results with Denon...

This is a review and detailed measurements of the Revel M55XC "extreme outdoor" speaker. It was kindly purchased new and sent to me by a member. I believe he is using it for surround on-wall application (indoor) due to small dimensions of this speaker. The retail cost for M55XC is $600 but there is a special (end of life?) going on bring the price for a pair down to US $420.

Note: our company, Madrona Digital, is a dealer for Harman and hence Revel speakers. I don't know for a fact but we install a lot of outdoor Harman speakers in commercial and residential installations. So feel free to read as much bias as you like into this review.

This is a very compact speaker as outdoor ones usually are:



There is sturdy metal grill that protects the drivers (which I did NOT use for measurements). The back panel shows screw terminals which is more of a standard for outdoor speakers (a boot covers and waterproofs it)...

This is a review and detailed measurements of the Topping D10s USB DAC and S/PDIF plus Toslink bridge. It was kindly sent to me by the company for testing. The D10s has a retail cost of US $99.

Let me start by confessing that the original D10 was one of my favorites with its cute orange display, and very reasonable cost. I was pleased that the former was kept the same although the price seems to have increased some:



The back panel is as before:



Note that the Toslink and S/PDIFs are outputs, not typical inputs. The Toslink can for example be used to break ground loops when feeding another DAC downstream of it.

As you see the markings, and like other Topping products, they enjoy full regulatory safety and emissions certifications.

DAC Audio Measurements
As usual we start with our dashboard of 1 kHz digitally created ton and examine what analog results we get:



Nice! SINAD which is...

This is a review and detailed measurements of the Salk WoW1 stand-mount/bookshelf speaker. It was custom ordered by a member and drop shipped to me. Standard pricing from the company is US $1,295 for black or white finish and $1395 for veneer (pair). The version I have for testing uses solid figured wood with custom staining so I suspect it cost even more.

The finish is furniture grade and definitely not something you find in mass market speakers:



You can see the figured (maple?) hardwood better on the back:



The stain/dye unfortunately makes the prized figure in the wood much more muted. Hopefully this is what the owner intended as otherwise a different finish should have been selected to bring out the beauty of "tiger" figure.

Measurements that you are about to see were performed using the Klippel Near-field Scanner (NFS)...

This is a review and detailed measurements of the Fosi Audio HD-A1 amplifier. It costs US $200 on Amazon including Prime shipping. It was kindly sent to me for testing by member @IowAudio. He has a review of it on youtube.

The front is not bad for a budget product:



The font could use some help but you don't listen to that. Nice to have a volume control as many budget amps don't have one.

The back panel connectors are unusually high quality:



Oddly the power switch is on the left (right above).

There are no safety or regulatory certifications which is always a concern for mains operated product.

In use the unit was quite robust, never shutting down or getting overly warm.

Company advertises that the topology is similar to Marantz's HDAM amplifier stage. Whether that is the case or not, I have not tried to investigate...

This is a review and detailed measurements of the powered Genelec 8030C Professional Monitor (speaker). It is on kind loan from a member and costs US $700 each.

The 8030C has the same look of Genelec speakers of the last decade or so:



To me it looks more "cute" than serious piece of gear.

There are a few dip switches in the back and control its operation:



I set all the switches on the right to off which tailor the tonality of the speaker. I left the gain at -6 dB as supplied by the owner.

Measurements that you are about to see were performed using the Klippel Near-field Scanner (NFS). This is a robotic measurement system that analyzes the speaker all around and is able (using advanced mathematics and dual scan) to subtract room reflections (so where I measure it doesn't matter). It also measures the speaker at close...

This is a review and detailed measurements of the Parasound JC2 Preamp. It was kindly sent to me by a member. The JC2 is replaced with JC2 BP. It cost US $4,000 when it first came out (2009).

This is one heavy preamplifier which weighs as much as some power amps!



The design is elegant and differentiated. There is independent gain controls for each input which can let you set channel balance. The knobs are very small and slippery though making this a bit hard.

The back panel shows where some of the cost has gone as these are probably the best connectors I have seen on an amplifier:



As I have magnified, the claim to fame of this preamp is the designer behind it: John Curl. If I were to name top 10 famous designers of audio electronics, he would have a solid spot there (as far as fame). He is quite active in forums as well. So it is very nice to get one of his designs on the bench and see how it performs...

This is a review and measurements of the Dosmix USB-C DAC and Headphone Amplifier adapter for phones. It was kindly purchased by a member and drop shipped to me. It is available on Amazon and costs US $21.89 including prime shipping.

From the outside, it is not much different than any other dongle:



Its claim to fame is usage of Qualcomm WHS9415 DAC+headphone amp.

As is typical of some of these adapters, the way they advertise themselves to Windows causes the ASIO wrapper I use to truncate samples to 16 bits. For this reason, the jitter and dashboard views were generated using WASAPI in my media player. For the rest of the tests, I did use the wrapper so there is a slight impact there but not much.

Headphone Adapter Measurements
As usual we start with our dashboard:



There is a mix of good and bad news here. The good news is that the SINAD which is a measure of noise and distortion is quite good for a...

This is a review and detailed measurements of the Revel M105 Bookshelf/stand-mount speaker. A member was interested in it so I decided to buy it through our company. The retail cost is US $750 each for a total of $1,500 for a pair.

NOTE: my company, Madrona Digital is a dealer for Harman and hence the Revel speakers. So please read as much bias as you like into this review.

The Revel M105 fits in the family with solid feel and very nice finish:



Terminals are large and easy to manipulate which I appreciated. I also like that the whole unit comes in cling plastic so keep it protected.

Measurements that you are about to see were performed using the Klippel Near-field Scanner (NFS). This is a robotic measurement system that analyzes the speaker all around and is able (using advanced mathematics and dual scan) to subtract room reflections (so where I...

This is a review and detailed measurements of the Behringer B2030P Studio Monitor, 2-way speaker. It is on kind loan from a member. Note that this is the passive version, not active. It has been discontinued and I can't find the original price in my search. I see one on sale on ebay for US $120 plus $60 shipping.

The sample I have has good bit of battle scars:



There is good bit of heft to it and seemingly the walls are quite thick relative to thin walls we see today.

Boy does the shape of the B2030 bring back fond memories of me buying my first studio monitor: a Genelec with the same vertical slot port (mine were active though).

Measurements that you are about to see were performed using the Klippel Near-field Scanner (NFS). This is a robotic measurement system that analyzes the speaker all around and is able (using advanced mathematics and dual scan) to...

This is a review and detailed measurements of the Okto dac8 stereo DAC. It was kindly sent to me by the company for review. It costs €1 089 from the company ($1,240 as of this writing). The version I have has the optional Raspberry Pi 4 module for streaming which costs an extra $89.

Last I tested a dac from Okto, it was their prototype 8-channel DAC. It set a new record in our measurements at the time, getting the highest "SINAD" score possible. While I loved many things about the hardware design, the case needed a new color and thicker sheet metal. Happy to report both of those have been managed producing a very professional and nice looking DAC:



As with the last model, the interface is a joy to use with large, bright text that changes lightning fast. An apple remote is provided for control which I used to good effect...

This is a review and detailed measurements of the AudioQuest Victoria Audio interconnect with "dielectric-bias system" (DBS). It is kindly loaned to me by a member and costs US $299.

The configuration I received is unusual in the way it has RCA connector at one end and some kind of 5-pin at the other end:



The "DBS" module is a simple battery holder for six (6) 12 volt little cells (type 8LR932). They are in series so produce 72 volts DC. A little LED lets you see if the batteries are still good or not. There is no on off switch so to turn the thing off, I had to unscrew the bottom and take out the batteries.

There is some kind of rubberized paint on the battery holder which has already started to degrade and become sticky. Yuck!

You have heard of anti-copy mechanism in movie content? Well, this device has an "anti-review" and "anti-measurement" feature in that the company claims even after you take out the battery its benefits remain for days...

This is a review and detailed measurements of the Project Phono Box DS2 phono preamplifier with USB capture capability. It is kindly loaned to me by a member. The DS2 costs US $599 from their dealers.

It is hard to differentiate in looks of desktop products but I think Project pulls this off nicely with a modern, European look:



A reassuring relay click is heard as you change gain settings that go form 40 to 65 dB in five steps. I only tested the 40 dB (ostensibly for moving magnet cartridges) and 65 dB (for moving coil).

Different than other phono preamplifiers is inclusion of USB capture:



You have the nice volume control to set the capture gain and choice of 48 kHz, 96 and 192 kHz PCM and DSD 128. I only tested the 48 kHz setting as otherwise you are likely just capture more noise.

A small external switching power supply generating 18 volts is used.

There is also a line in input so you can use the DS2 as a general...