Articles, Reviews and Measurements of Audio Products

Behringer DCX2496 EQ Review

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This is a review and detailed measurements of the Behringer Ultra-Drive Pro DCX2496 digital EQ and speaker crossover. It was kindly sent to me by a member and costs US $359.
Behringer Ultradrive HD Pro DAC Speaker EQ crossover Digital Review.jpg

The main purpose of the unit is for professional sound reinforcement allowing crossovers for up to 3-way speakers in stereo. You can see this from the back connectors:

Behringer Ultradrive HD Pro DAC Speaker EQ crossover Digital DCX2496 Review.jpg

You configure the three input channels and their routing to output with many configuration parameters. Inputs are normally analog but Input A can be configured as digital AES/EBU (balanced) digital input. The coarse/old fashioned LCD is kind of hard to read (but better than image above) but gets the job done. Documentation is bare minimum with little explanation of some of the terms. Took me a good two hours to figure out how to set it up for my testing. But for someone using it everyday for their job, it should not be hard.

I wish there was Ethernet support with an...

Spinorama for the brand new JBL PRX900 serie

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JBL PRX900 are PA speakers which are optimised for high output. They are active, relatively cheap, easy to get and have an internal DSP. JBL is nice enough to provide a lot of datas for these speakers. I used the data to generate the spinorama and derive some information.

Here is the marketing blurb from JBL:

JBL PRX900 Series powered loudspeakers and subwoofers take professional portable PA performance to a new level with advanced acoustics, comprehensive DSP,
unrivaled power performance and durability and complete BLE control via the JBL Pro Connect ecosystem. The line, which includes three powered two-way loudspeakers and two powered subwoofers, has been entirely built from the ground up to leverage JBL’s most advanced acoustic innovations. Next-generation driver systems—powered by ultra-efficient 2,000-watt (peak) Class D amplifiers—deliver clarity and definition at maximum volume, with improved dispersion and smooth low-frequency extension. The PRX900 Series is a...

Aperion N5T Speaker Review

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This is a review and measurements of the aperion audio Novus N5T 2-way 5.25" tower speaker. It was sent to me by the company and costs US $1,398 a pair.

Aperion Audio Novus Tower Speaker Review.jpg

Sorry for the stock image. Speaker has been here for a long time and I just have not had time to do anything with it other than measurement. I was pleased how light-weight it was as I could lift it by myself to put on the tall measurement stand. The design is unique although configure is not as an MTM (mid-woofer, tweeter, mid-woofer).

Measurements were performed without the grill. It has been a while but I think the reference axis was around tweeter center.

Aperion N5T Novus Speaker Measurements
As usual we start with our frequency response measurements:
Aperion Audio Novus Tower N5T Speaker frequency response measurements.png

As noted, response is reasonably flat other than the disturbance in lower treble area of 2 kHz. Directivity changes a lot as well due to interference from the two woofers. The tall cabinet...

Emotiva Big Ego+ Portable DAC & HP Review

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This is a review and detailed measurements of the Emotiva Big Ego+ USB stereo portable DAC and headphone amplifier. It was kindly sent to me by a member costs US $79.10 from company website.

Emotiva Big Ego+ Stereo USB DAC Review.jpg

For a portable product it is quite large but that also makes it a better fit for desktop use. Compared to typical dongle, you have a few more features:
Emotiva Big Ego+ Stereo USB DAC Toslink Portable Review.jpg

It can act like a digital bridge taking USB input and converting it to Toslink optical. You can then select between it and analog line out. USB input though is the very old fashioned mini USB which tells me this design is fairly old. You also have a choice of a few reconstruction filters which is never found on this class of device.

Emotiva Big Ego+ DAC Measurements
Let's start with line out:
Emotiva Big Ego+ Stereo USB DAC Measurements.png

Disappointed to see less than 2 volt output and high distortion which dictates SINAD to be in our "red"(poor) category:

Expert Talk: What Is Bandwidth and Why Do I Care?

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What Is Bandwidth and Why Do I Care?

Zoom Meeting: Thursday, November 17th, 2022, 6PM PST (UTC -8)
image linked to jj_491x492.jpg
To attend this FREE event, Click Here to access Eventbrite for this event.
NOTE: Ticket sales end when the meeting begins.

Have you ever wondered
why your digital audio system can not "miss" that spike that happens entirely between samples? Have you ever wondered how you can get subsample time resolution in digital systems, without even trying? Well, here's the answer, signal bandwidth.

This talk explains what restricting the bandwidth of a signal does, necessarily, to the signal. To the first question above, no, that signal can not ever even exist unless it's many, many times outside the bandwidth...

AIYIMA A08 Pro Amplifier Review

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This is a review and detailed measurements of AIYIMA A08 Pro stereo amplifier with Bluetooth support. It was sent to me by the company and costs US $139.99.
AIYIMA A08 Pro Stereo Amplifier Bluetooth Review.jpg

It is so nice to see a VU meter on an amplifier! This one actually seems high quality with nice ballistic response (fast jump, a bit slower retard). Bass and Treble controls are there but I wish there was a tone defeat as well. The position of the indicators is where I had to set them for more or less flat response. I do like the very fine detents on it, allowing you to more precisely adjust them at least.

The included power supply is one of the largest I have seen but is rather light for its size:
AIYIMA A08 Pro Stereo Amplifier Bluetooth back panel power supply Review.jpg

There are no remotes so the amp is for desktop use. Class D implementation means the amp ran with no temperature rise...

Measuring 2-channel Buckeye Purifi Amplifier Performance

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With Amir busy with house repairs, @Buckeye Amps and I discussed whether I might share some of my efforts to measure his Purifi amplifier as a stop gap until Amir can do so. A couple of disclaimers here as I am NOT an experienced electrical engineer and my QuantAsylum test rig is NOT as capable as Amir's AP analyzer. Should also point out that this amp was built by me using Buckeye's parts. I expect his build is almost identical but could be some slight differences. All said, we still thought this might be useful in the interim.


So first, my basic test rig consists of a QA401 audio analyzer and a QA451 programmable load. The test load provides 4 and 8 ohm resistive loads and includes a 6th order low pass filter help deal with "filterless" Class D amplifiers. The QA451 is capable of measuring up to about 300 watts of power for short bursts. The...

Is FR the only important measurement? Real life testing.

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So I've been watching this guys videos for a while, he is an empirical data kind of scientist, and in this video regarding guitar amps he has the holy grail of audiophile terminology, applied to guitar amplifiers, debunked in its entirety.

This is not exactly revelaing anything we didnt know here at ASR, but its a good video to refer to those audiphiles that dont believe in math or data charts since it has empirical listenable data. Its not exactly hifi audio related, but amps are amps, and audiophoolery is audiophoolery, so it kind of overlaps with ASR's ethos. And if anything its an entretaining video to watch on amplification myths.

Denon AVR-X3800H Review

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This is a review and detailed measurements of the Denon AVR-X3800H 9.4 Home Theater Audio/Video Receiver. It was kindly drop shipped to me by a member and costs US $1,699.
Denon AVR-3800H AVR Home Theater Dolby Atmos IMAX Audio Video Receiver Review.jpg

Not much to say about the look of the unit as it is pretty much similar/same as last generations. Here is the back panel:
Denon AVR-3800H AVR Home Theater Dolby Atmos IMAX Audio Video Receiver back panel Review.jpg

I had one operational problem with the unit where the Setup button would not bring up the menus anymore. A power cycle fixed it. I was happy to see solid extruded aluminum heatsink. Despite that, the top front of the of the unit (above the heatsink) got quite hot to the touch. I highly recommend ample airflow in that area. As usual, there is a fan there but it would not come on to cool the unit.

I grabbed a preliminary set of measurements from the DAC section of the 3800H and ran it by the company. Within typical margin of error, the measurements were the same as company's own.

Denon AVR-X3800H DAC Measurements...
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