15 of 24 people found the following review helpful
Great sound, horrible radio interference,
This review is from: KRK VXT4 Active Studio Monitor - 4 Inch, 45 Watts (Electronics)
I so wanted to like these speakers, I listened to them extensively, among with other speakers of the same price tag, before I bought them and they were clearly the winners. I bought a pair along with 2 Mogami Gold TRS calbes, about $50 dollars a cable, good stuff. When the speakers arrived I plugged them in and as soon as I connected the speaker cable (6ft) to them I started listening to radio! I didnt even connect them to my audio interface (Audio Kontrol 1 from Native Instruments no less). I could listen clearly to a radio station. I thought that the Mogamis were defective and switched them around but both speakers had the same problem with different cable configurations. I was devastated. I looked on the web and sure enough other people have complaints about the poor shielding of this speaker. And it is not any ground loops since the minute I remove the speaker cable there is no humming noise and they are super silent. After reading some articles I started some shielding experiments with aluminum foil and to my surprise I made the following discovery. When there is an electrical connection through the foil from the push pin of the XLR/TRS combo jack in the back of the speakers with one of the little switches in the back of the speaker the interference goes away. Wow! I cant believe that KRK didnt do its homework shielding these great speakers properly. I have read on the web that some people have actually opened them up and installed tin foil along the sides of the speakers. I am not sure I am going to go that far. I am calling KRK and see what they have to offer as a solution but most probably I am returning them back. Such a same. The sound is really great, so much clarity and punch out of these speakers but the interference problem is really intolerable.
Tracked by 1 customer
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Showing 1-4 of 4 posts in this discussion
Initial post: Jul 6, 2009 11:50:33 AM PDT
Last edited by the author on Jul 6, 2009 11:52:58 AM PDT
B. Weber says:
If the speakers are quiet with no cable attached then there would not appear to be any shielding problem with the speaker. However, by apparently having a cable connected to the VXT4 and leaving it unterminated on the other end you did essentally attach an antenna to the monitor's input and that might explain some RF pickup on the input.
If the cable was terminated at both ends and unplugging it made the noise go away then that does indicate a possible ground loop issue, exactly the opposite of what is stated. Ground loops would only be relevant if the monitor was cabled to another device as that is what is required for the loop aspect and disconnecting the cable would break the loop.
The online discussions I have found related to excessive noise with teh VXT4 seem to often be an issue of the VXT4 level being turned all the way up, which is not required for most use.
So, did you try the VXT4 with the cables connected to your audio interface? Did you try some other cables or try the Mogami cables with other equipment? Did you try turning down the input level on the monitors? There may indeed be a problem but it appears that perhaps your troubleshooting and deductions were a bit flawed and you might be blaming the VXT4 shielding for an unrelated problem.
Posted on Jan 10, 2011 12:22:49 PM PST
Last edited by the author on Jan 10, 2011 12:23:36 PM PST
Oliver Baptiste says:
I have a pair of VXT4s and they sound great, but I also get RF interference, a faintly audible FM radio station. I've had them for about a year and finally decided to call KRK support about the issue. Seems that they are aware of it but it happens to such a small number of users that they can't really support the issue. Seems that most of their customer base aren't close to radio transmiters, while the Reviewer and I are in Manhattan and very close to 50,000 watt FM radio transmitters. They suggested moving them to another location but I have a very limited space to work with. Luckily, it's not at a volume that is intolerable for me.
In reply to an earlier post on Dec 5, 2012 10:38:14 AM PST
J. Ingram says:
Thank you for responding intelligently to this review, I think more information is needed about his scenario before he can definitively say "these speakers are susceptible to interference."
Posted on Jan 24, 2014 6:10:34 AM PST
An unterminated cable acts as an antennae. As soon as both ends are terminated the am/buzz will go away. Its not a defect in the speaker, it adding a coaxial cable that is acting as an antennae. This is very common among professional audio gear. I have seen it a lot.
There is also a ground lift switch on the speaker, i bet if you toggled that it would have cut the am reception also.
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