Articles, Reviews and Measurements of Audio Products

Topping L30 Headphone Amplifier Review

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This is a review and detailed measurements of the new Topping L30 headphone amplifier. It is a companion to their E30 DAC. I don't have official pricing on it but see it on some sites for US $130.

This is a compact unit but with nicely thought out controls:

Topping L30 Headphone Amplifier Audio Review.jpg


There was a plastic cover in the front which had very clear labels on it. But once I pulled it off, I realized the real labels are not as easy to read. So you may want to leave that plastic on it. Then again there is not much to remember here to need the labels. The left switch controls whether the output is the headphone or line out in the back. And there are three useful gain modes: -9, 0 and +9 dB. The first one is super useful for very sensitive IEMs and headphones allowing the volume control to operate in its most accurate range.

The back panel is as you expect but there is a change in...

Ascend Acoustics Horizon Center Speaker Review

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This is a review and detailed measurements of the Ascend Acoustics Horizon Center speaker with RAAL tweeter upgrade. It costs US $1,495 according to its owner ($350 tweeter upgrade fee).

The Horizon is a heavy beast and seems well finished:

Ascend Acoustics Horizon RAAL tweeter upgrade Audio Review.jpg


It is too heavy for my photo booth so you see it where I put to listen to it. The fabric under it is made out of special material that helps push the electrical energy that would normally be wasted in speaker/crossover wires back into the speaker. I plan to market it as an effective tweak but we digress.

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...

PS Audio M700 Monoblock Amplifier Review

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This is a review and detailed measurements of the PS Audio Stellar M700 Power Amplifier. It is kindly sent in by a member and costs US $2998 for a pair from the company direct.

The M700 is quite heavy for a class-D amplifier. I picked it up by hand and nearly hurt my back trying to hold it that way!

The industry design is well, a bit industrial but follows the rest of PS Audio:

PS Audio Stellar M700 Power Amplifier Audio Review.jpg


Back panel is simple and as expected exception for inclusion of duplicate binding posts for "bi-wiring:"

PS Audio Stellar M700 Power Amplifier Back Panel Inputs Connectors Audio Review.jpg


In use, the amplifier didn't even get warmer. It did shut down when overloaded with my stress test of 20 kHz tone but otherwise was stable.

Overall, I am happy with the look and functionality of the M700.

Amplifier Audio Measurements
As usual, we feed the amplifier a near perfect 1 kHz analog signal and examine what else comes for the ride in its speaker terminal output:

PS Audio Stellar M700 Power Amplifier Audio Measurements.png


The gain is a bit higher...

PSB Alpha P5 Speaker Review

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This is a review and detailed measurements of the PSB Alpha, 2-way budget speaker. I purchased it a couple of months ago from Amazon. Cost is US $349 there including Prime shipping.

If you are not familiar with PSB, those are initials of Paul Barton. Paul worked under/with Dr. Folyd Toole while at Canadian NRC so calls from same set of research as Harman folks. The speaker in question won streophile product of the year award in 2019.

It is hard to stand out in the crowded market of budget 2-way speakers but PSB makes an attempt with upside down configuration (tweeter on the bottom) and slick magnetic grill (not shown):

PSB P5 Bookshelf 2-way speaker Stereo Review.jpg


Back panel is ordinary sans a screw for rear mount (which then makes you wonder about the rear port):

PSB P5 Bookshelf 2-way speaker Back Panel binding post Stereo Review.jpg


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

Fiio Q5s Portable DAC & THX Headphone Amp Review

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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:

Fiio Q5s USB DAC Bluethooth Portable Headphone Amplifier THX Audio Review.jpg


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:

Fiio Q5s USB DAC Bluethooth Portable Headphone Amplifier THX Module Back Audio Review.jpg


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

SVS Ultra Bookshelf Speaker Review

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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:

SVS Ultra Bookshelf 2-way Speaker Home Theater Audio Review.jpg


There are dual binding posts in the back:
SVS Ultra Bookshelf 2-way Speaker Home Theater Back Panel Binding Posts Audio Review.jpg


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...

Denon AVR-X3700H AVR Review

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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:

Denon AVR-X3700H 9.2 channel 8K AV Receiver Dolby Atmos Audio Video Review.jpg


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:

Denon AVR-X3700H 9.2 channel 8K AV Receiver Dolby Atmos Back Panel Inputs HDMI Connectors Audi...jpg


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...

Pioneer XPA-700 Portable Headphone Amp & DAC Review

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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:

Pioneer High-res XPA-700 DAC and Portable Battery Headphone Amplifier Review.jpg


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

Pioneer High-res XPA-700 DAC and Portable Battery Headphone Amplifier Front Panel Review.jpg


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...

GR Research X-LS Encore Kit Speaker Review

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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:

X-LS Encore Kit DIY Speaker Review.jpg


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

X-LS Encore Kit DIY Speaker Bookshelf 2-way Back Panel  Review.jpg


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...

Advent Model 300 Vintage Receiver Review

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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:

Advent Model 300 Receiver Vintage Audio Review.jpg


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:

Advent Model 300 Receiver Vintage Back Panel Inputs Audio Review.jpg


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...

BIC America DV62si Bookshelf Speaker Review

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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:

BIC DV62Si 2-way bookshelf speaker review.jpg


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:

BIC DV62Si 2-way bookshelf back binding posts port speaker review.jpg


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...

Denon AVR-X6700H Home Theater AVR Review

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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:

AVR-X6700H AVR Surround HDMI Dolby Atmos Home Theater Receiver Review.jpg


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

AVR-X6700H AVR Surround HDMI Dolby Atmos Home Theater Receiver Back Panel Inputs Outputs Review.jpg


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...

Revel M55XC Outdoor Speaker Review

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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:

Revel M55XC Wall-mount outdoor speaker Review.jpg


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)...

Topping D10s USB DAC and Bridge Review

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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:

Topping D10s DAC USB Audio Review.jpg


The back panel is as before:

Topping D10s DAC USB Back Panel SPDIF Toslink Digital Inputs Audio Review.jpg


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:

Topping D10s DAC USB Audio Measurements.png


Nice! SINAD which is...

Salk WoW1 Bookshelf Speaker Review

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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:

Salk WoW1 Bookshelf Speaker 2-way Audio review.jpg


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

Salk WoW1 Bookshelf Speaker 2-way back panel custom finish Audio review.jpg


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)...

Fosi Audio HD-A1 Budget Amplifier Review

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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:

Fosi Audio HD-A1 Hi-fi Power Amplifier Audio Review.jpg


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:

Fosi Audio HD-A1 Hi-fi Power Amplifier Back Panel Input Binding Posts Audio Review.jpg


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...

Genelec 8030C Studio Monitor Review

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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:

Genelec 8030C Professional Studio Monitor Speaker 2-way Audio Review.jpg


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

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

Genelec 8030C Professional Studio Monitor Speaker 2-way back panel inputs switches Audio Review.jpg


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...

Parasound JC2 Preamplifier Review

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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!

Parasound JC2 Preamplifier Balanced Audio Review.jpg


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:

Parasound JC2 Preamplifier Balanced Back Panel XLR Audio Review.jpg


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...

Dosmix Headphone Dongle Review

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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:

Dosmix HIFI DAC Earphone Amplifier Qualcomm WHS9415 Audio Review dongle.jpg


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:

Dosmix HIFI DAC Earphone Amplifier Qualcomm WHS9415 Audio Measurements.png


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...

Revel M105 Bookshelf Speaker Review

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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:

Revel M105 bookshelf speaker Audio Review.jpg


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...
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