Articles, Reviews and Measurements of Audio Products

After finishing @Floyd Toole 's The Acoustics and Psychoacoustics of Loudspeakers and Rooms, I became interested in conducting a blind listening test. With the help of a similarly minded friend, we put together a test and ran 12 people through it. I’ll describe our procedures and the results. I’m aware of numerous limitations; we did our best with the space and technology we had.

All of the speakers in the test have spinorama data and the electronics have been measured on ASR.

Speakers (preference score in parentheses):

Kef Q100 (5.1)
Revel W553L (5.1)...

This is a review and detailed measurements of the Dual DA10004D Car audio amplifier. It has 4 channels and is on kind loan from a member. It is sold everywhere it seems for just US $110.

Despite its very low cost, the Dual brings a bit of style to the party:



The shocking bit is on each end:



Check out the beefy power terminals and array of filtering and gain settings. I had no trouble getting my 8 gauge power cables into its terminals. Both low pass and high pass filtering is provided together with bandwidth for each.

I have been testing a few car audio products but good bit of frustration. When I used to repair them decades back, we always had a lead acid battery to power them so that we could have a) plenty of juice and b) not have mains interference. In anticipation of getting this amp to test, I decided to bite the bullet and build a high-current LifePoFE4 battery. I had four spare cells from my work on our...

This is a review and detailed measurements of the Genelec 8330A studio monitor (powered speaker). It was kindly purchased by a member and drop shipped to me. The 8330A costs US $895 each.

The 8330a naturally follows the current design style of Genelec 2-way non-coaxial speakers:



This is part of the smart speakers from Genelec so naturally sports Ethernet connectivity:



I performed a factory reset before testing. I was surprised how sensitive the input was. I had to really dial down the output on my Klippel analyzer to measure it. I expect devices targeting professional market to have less gain by default when using XLR connections.

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...

This is a review and detailed measurements of the Sabaj A10h headphone amplifier. It was sent to me by the company and cots US $120 on Amazon including Prime shipping.

Note: without asking, the company made a generous donation to the forum prior to this review. As you can imagine, such can't change the nature of my testing as most are objective and identical to others. It did however made me guilty to finally test this amplifier after it was sitting for some two months here. But if you like to read some form of bias into this review, you are welcome to do so.

The A10h distinguishes itself from others in its price range in two ways starting with a digital display of the volume:



And secondly by stepped relay volume control which should translate into great channel matching. Usually such volume controls are reserved for higher priced amplifiers.

While I appreciate the channel matching such controls provide, I don't like the slow...

This is a "half" review of the Mytek AMP+ stereo class D amplifier. I say "half" because one channel is broken in it. After consultation with the owner who kindly sent it to me, I decided to measure the working channel since the company says it is a "dual mono" configuration. The AMP+ costs US $2,500 from the company.

It is amazing how small Class D amplifiers are as Mytek has managed to stuff it in the same box as their desktop DACs!



The "M" logo lights up all around it in blue when you power it on and gets brighter when you push the power switch in the front. The back side has what you expect:



Speaker terminals are close to each other so a bit hard to get heavy cables into them but you can manage.

The unit supports bridge mode so I thought maybe that was activated and was the reason one channel was not working. Went to find the manual and it was very difficult. Eventually I found one on their European site...

Just finished a video review of the KEF LS50 Meta speaker for those who like to watch things in that format. There is also a more detail and explanation of what the measurements mean than what I include in the text review:


Text review and discussion at: https://www.audiosciencereview.com/forum/index.php?threads/kef-ls50-meta-review-speaker.25574/

This is a review and detailed measurements of the Apple AirPods Max wireless Bluetooth noise cancelling headphone. It is on kind loan from a member. The retail cost is US $549 but I see it on Amazon for $479 including Prime shipping.

I am used to shocking good looks in Apple products but this one with dual kidney shape did not do it for me:



The mesh band was stylish though as was the design of the woven pads. What I absolutely loved was the rotary volume control. Shame on all others that make you deal with gestures and such with coarse volume adjustment to boot. I also liked the solid, tactile button for noise cancelling. Alas, that button is way overloaded, requiring you to decode Morse code light at the other end to figure out what you are doing with it. Why not voice feedback? Anyway, you get the job done.

Noise cancelling works well but has that "suction" effect to the max. It literally feels like there is a vacuum cleaner inside this...

This is a review and detailed measurements of the 2021 Bluesound Node wired and wireless streamer and DAC. It is the next generation from Node 2i which I reviewed a while back. The Node costs US $549 and was kindly drop shipped to me by a member. In case you don't know, Bluesound is from the same parent company as NAD.

The Node looks as attractive as the last generation:



That said, I can't figure out anything on it. Hopefully the app helps.... Not!!! There is no remote so I downloaded the app to try to figure out how to change inputs. The app downloaded fine and prompted me to upgrade the unit. I let it and it spent some 10 minutes doing so! This is way too clunky. What on earth is it doing for 10 minutes? It rebooted but then nothing would work in the app. The gear icon would do nothing. And neither would the...

This is a review and detailed measurements of the KEF LS50 Meta bookshelf coaxial speaker. It was kindly purchased new by a member and drop shipped to me and costs US $1,500 for a pair.

The LS50 Meta comes in different colors and I must say, it looks stunning in white:



You could sell it as a decoration piece and it would still sell strongly!

Even the back panel oozes beauty and custom design:



Love the wide apart binding posts that are easy to tighten and loosen.

Speaker also feels quite dense and solid which is good.

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...

This is a video version of my article on AC distortion and noise impact on fidelity of audio equipment:


Text thread: Impact of AC Distortion & Noise on Audio Equipment | Audio Science Review (ASR) Forum