dbx 120A Subharmonic Synthesizer
dbx 120A Subharmonic Synthesizer is rated out of 5 by 3.
Rated 5 out of 5
from Good for home-audio use, too.At one time I owned the earlier version of the dbx 120 and also owned an AudioControl Phase-Coupled Activator, which was designed to do much the same thing. I sold both off in a spate of downsizing (I had been an audio reviewer, audio book writer, and audio journalist for years), and after a short while was sorry I did so.The newer 120A version is designed mainly for pro use, but if installed in a subwoofer circuit (I use just one of its two available channels with the mono-sub feed from my receiver) it can benefit action-movie sound even more than it benefits pop music, either played back from discs or being created at a club or concert. The hookups are a bit tricky, since while it can handle RCA-jack inputs, it requires a balanced link to any subwoofer power amp downstream, and some minor-grade subwoofers simply do not have that hookup feature.My rig, even downsized, does have the proper hookup options. The 120A links to an ART 351 mono equalizer (also purchased from Parts Express), via a TRS cable. The ART has 31 one-octave bands, only the bottom seven of which (80 Hz and down) I use. However, it does a fine job of taming room resonances, and also for ramping up the output 4-6 dB or so below 30 Hz. The feed from the 351 goes, via standard RCA cables, to a splitter that feeds both channels of a Crown XLS1000 power amp (also purchased from Parts Express), and the amp feeds a pair of Dayton Titanic 12-inch drivers mounted in a pair of 4.5-foot tall cylinder-type subwoofer enclosures I built myself. The combo is flat to 20 Hz.I wanted the 120A for use with older action/adventure and sci-fi movies that lacked serious deep-bass punch. However, after using it for a while I discovered that with careful adjustment it does even better with the newer movies, simply because, the recording and editing technology notwithstanding, few of those movies have any serious bass below 30-40 Hz. The 120A fixes that problem nicely.It obviously also can work wonders with rock music (which I do not listen to much) but is not advisable for use with acoustic music, either classical or jazz. The electronic "boost" is just not appropriate.The knob three controls I use on the unit are the subwoofer boost control, the 24-36 Hz control, and the 36-56 Hz control. The 24-36 is the most critical when it comes to fine tuning, because, since I use the unit with the sub-out hookup of my receiver, crossed over at 80 Hz from the satellite amps. This means that only bass below 80 Hz gets any half-frequency generation. Hence, the 36-56 control only has marginal impact, with only signals between 36 and 40 Hz being involved. The 24-36 control gets plenty of input to work with, however.The two remaining knob controls get no use at all and are not needed, anyway. Since I use my receiver's own crossover for the subwoofer feed, the subwoofer level control on the 120A is not engaged at all. The other control, LF Boost, is designed to handle frequencies somewhat above the range handled by the synthesizer, and most of those frequencies are above 80 Hz.This is a superb unit. If it has any deficiency for a home user it is that if the power is cut simultaneously with the power to the sub amp you will get a substantial "thump" as the power supply disengages. My solution is to leave the 120A plugged in 24/7, since it draws little power from the wall jack. Also, if you have your rig hooked up to a cable video feed you may get some ground-loop hum. While a cable filter can eliminate some of this, you can also use a cheater plug to essentially "lift" the ground (the ART equalizer has an on-board switch for this, but he 120A does not), which should eliminate the hum completely.This is a great tool for those who want to create music and an equally great one for those who want to soup up the sound of their audio rigs, either for pop music or home theater.Howard Ferstler
Date published: 2014-03-12
Rated 5 out of 5
by Monoman - 08982
from Fully adjustable bass machineThis thing is a dream come true.You can get as little or as much bass as your system can handle. Bass frequencies can be sent to a subwoofer or to the main speakers.I am using this in a home stereo and it is just what is needed to fatten up the bottom octave.Give it a try, you won't be sorry.
Date published: 2008-03-16
Rated 4 out of 5
by Dusty - 07311
from GreatI use it for program music and it is awesome. It allows you to adjust the 29-36 hz range and the 36-59 hz range. It really seems to get the bass down low and clean it up a bit too. It allows you to fill in the bass between the sub and the floor speakers so there is not a gap and allows you to set the level of the sub output and the overall level of the bass the box puts out. It has a built in x-over that can be used and the pre-sets are 80hz and 120hz.
Date published: 2008-02-04