Average Reviews:
(More customer reviews)I picked up a pair of BX8a Deluxe speakers on Amazon for a great price. I did some reading online and read about speakers randomly dying after purchase, but the price was just too good and I decided to roll the dice.
Well, 2 months in, my right speaker went bad and never would work properly again. When I would turn it on, the woofer would pop, go full throw, and emit a 60Hz hum. Very bad stuff. I looked at my return / repair options and found I had to return them to M-Audio to get it repaired.
I looked at the M-Audio forums and read quite a bit more about M-Audio speakers failing, and decided I'd take my chances and crack open the speaker to see if I could figure out what was wrong instead of suffering through a potentially long and painful RMA cycle.
3 hours later I had discovered the problem: a short circuit on the main amplifier board, underneath the tweeter's power amplifier chip. The amp is a TDA2052 made by STMicroelectronics. You can look at the datasheet here: http://www.st.com/stonline/products/literature/ds/1585.pdf
The short was between pins 4 and 6 of this chip, so it was connecting the negative power supply voltage to the audio input pin on both the tweeter and woofer amplifier - very bad! This explains why I could hear 60Hz power line noise on the speaker every time I turned it on.
I was about to start probing each pin on the TDA2052 to see if I could figure out what wire on the circuit board had a problem when I discovered the short between pins 4 and 6. I carefully removed the solder flux and other debris between the two solder pads and plugged the circuit board in, and the problem was gone. You can see a picture of my circuit board and the location of the short here: http://img212.imageshack.us/img212/3357/img0054un5.jpg
As to why the short-circuit suddenly occurred 2 months after purchase - I can only speculate. One possibility is the dreaded "tin whiskers" problem that has been plaguing electronics manufacturers for years. You can read about it here: http://nepp.nasa.gov/WHISKER/
Since lot's of people are reporting random failures of these speakers, this is a possibility. There are a couple ways to remedy this, but they all involve tweaking the manufacturing process of the circuit board, and this might not be an option because it would impact the cost and profit margin on these speakers. The other possibility is that the assembly quality control is not good enough on these circuit boards and they are not adequately stress tested / verified before being put into the finished product. Again there is a cost issue and I'm just speculating.
Overall I must say the speakers are an excellent value for the price. The speaker box construction is solid, the speakers are decent, and the electrical design is good enough - simple and effective. I am impressed with this product, and it is unfortunate such a great product is subject to such a high failure rate from what looks like a manufacturing/quality issue and not a design problem. I just hope M-Audio can remedy the issues long term as I'd like to see them continue to develop quality products.
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M-Audio Studiophile BX8a Deluxe 130-watt Bi-amplified Studio Reference MonitorsRecording professionals around the world trust M-Audio Studiophile reference monitors for exceptional sonic accuracy. The new Studiophile BX8a Deluxe system builds on this legacy with new waveguides and enhanced driver integration for greater high-frequency clarity and refined sound. The magnetically shielded monitors feature 8-inch curved Kevlar low-frequency drivers plus high-temperature voice coils and damped rubber surrounds for durability and fidelity. The 1-1/4-inch natural silk, waveguide-loaded tweeters deliver a high end that's both clear and easy on the ears. Custom-tuned crossovers distribute 130 watts of bi-amplified power for optimal frequency handling by each driver.
Deluxe Edition The Studiophile BX8a Deluxe monitors update the best-selling M-Audio BX8a system with a variety of enhancements. The new waveguide delivers a cleaner sound. Custom amplifier tuning enhances the integration between the high and low frequencies, delivering refined spectral balance and a smoother response. An elegant new industrial design completes the package.
Kevlar Low-Frequency Drivers To insure a lifetime of service, we constructed the BX8a monitor's 8-inch low-frequency driver from woven Kevlar. Kevlar's high mechanical and thermal resilience makes it ideal for use in speaker cones. Our engineers also created a curved conical design that improves room dispersion. High-damping reliable rubber surrounds provide percussive musical bass, and insure that the cone reaches its optimal excursion for accurate reproduction. And our high-temperature voice coils reduce power compression, guaranteeing that your monitors will deliver full performance hour after hour.
Silk-Dome, Waveguide-Loaded, High-Frequency Drivers Our high-frequency domes are made from natural silk to counter the high Q ringing that is inherent in the poorly crafted metallic materials often found in other monitors. In addition, our new waveguides refine the high-frequency response. M-Audio's FerroFlow technology uses ferrofluid liquid cooling to dissipate heat for maximum efficiency and extended usage.
Bi-Amplified Efficiency Active monitors have a distinct advantage over unpowered monitors because the built-in power amps are specially designed to work with the drivers and crossovers in a tuned system. Bi-amplification further refines the concept by dedicating separate power amps to the highs and lows. Combined with a finely tuned crossover, this design insures that both the high- and low-frequency drivers are asked to deliver only the frequencies they are most efficient at reproducing.
Rear-Ported Cabinet Design The Studiophile BX8a Deluxe monitor's cabinet is integrally designed with its other components for optimal performance—right down to rounded corners for reduced edge diffraction and superior imaging. Custom rear-port design audibly reduces the turbulence and resulting distortion caused by poorly designed ports.
Magnetic Shielding Unchecked, the electromagnetic waves emanating from your speakers can wreak havoc with your computer's video monitor or a nearby TV. The BX8a Deluxe is magnetically shielded so that all of your electronic equipment can coexist without interference.
What's in the Box Two BX8a Deluxe Speakers, Two Detachable AC Power Cords, User's Manual
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