INTRODUCTION TO BASS AND ITS PROBLEMS…
To have a great sound from the midrange and up is easy. As long as the speaker is kept reasonably far from hard reflective surfaces and the whole environment is balanced (in acoustic terms), your ears will automatically lock onto the direct arrival sound in the mids and highs (100 Hz and up), and room effects won’t keep the top from sounding good or sometimes even phenomenal.
For the lower frequencies, however, it’s a very different story. Any room almost inevitably plays havoc, no matter how good the speaker is an anechoic measurement. Below 100 Hz, the speaker’s sound is being reflected around by the room and the direct sound arrives to your ear in one big lump with the room effects. The phenomenon of a boom somewhere below 100Hz and a large dip between 100Hz and 200Hz is far too common.
… AND THE FIXES…
These negative room effects can be somewhat tamed by careful placement. However, regardless how one places speakers, there are inevitably deviations from smooth response in the bass, arising from the fact that listening rooms of domestic size have room modes—resonances quite widely spaced in frequency in the lower part of the audible range. Any listening room, regardless of size and how carefully placed the acoustic correction panels are can not make the room mode completely disappear. Even concert halls, which obviously are much larger, have resonances too, although due to the closely spaced resonances they are now called reverberation that can be quite smooth in frequency response.
WHEN THE FIXES FAILED…
When the room acoustics have been treated to the hilt, a good part of the remaining room resonances should be and can be corrected electronically. There are devices to do this correction and have become increasingly popular in recent years. There are also a quite number of sub woofers now come with such adjustments built in, namely the Paradigm DSP-3200 with its Perfect Bass Kit add-on system as one of, if not the, best bass correction unit out there. However, what about the existing system? Not everybody wants to buy a new subwoofer system. To varying degrees there is Audyssey system, rather effective, but in Canada it costs around $800. Alternatively, if money is no object, there is a very effective Rives PARC, but at that price, it is still a bandage solution so you might as well buy the absolute best Paradigm subwoofer with Perfect Bass Kit.
Enter DSPeaker Anti Mode 8033s add-on unit. Yes, it is a bandage, but unlike the other bandages, this one costs less than $600, a far more realistic price for everybody. From the price point, I’m already gravitating towards it. Furthermore, due to my notoriety in writing a no-nonsense and politics-be-damned review, some companies have refused to have their products reviewed by me. This is not the case with this company. Even after showing them the samples of both my negative and positive reviews they are still very enthusiastic and I received my review sample overnight from Finland.
Installation is as easy as plugging a power cord. The device puts a signal into the subwoofer, letting the supplied microphone “listen” to the result at your intended listening position; the device then analyses and remembers what should be done to make the bass response to be measurably better. For best results, as mentioned earlier in the article, start with a proper placement that avoids large or broad peaks and dips… especially dips. The Anti-Mode 8033 only pulls down peaks and will not push the dips up. After you’re done, you may need to set your overall subwoofer level slightly higher to get the same subjective effect as before, since the system will have removed the boominess that arise from room resonances.
For the first test I use my old and trusty Disney’s Bolt (chapter 2). The scene literally opens with a deep bass. I’ve always had problems playing this track because of some bass bloat especially in the 25 Hz area that rattles my screen. I usually have to dial no more than -20 dB from reference level with LFE set to -5 dB. After 8033 calibration, I can now set the volume to -17 dB (this is as loud as my ears can handle) with LFE set to 0 dB. That’s an overall of 8 dB improvement in the overall 25 Hz bloat that’s been reduced from my room. Not only that, there must also be some bloat around 80 Hz because some of the bad-guy character’s voice was somewhat muddled. Again with the 8033 in-line, the dialogue clarity has been much improved. Even the synthesizer bass line that underlines the entire chapter 2 also benefitted from the depth and precision of the bass and the excellent pitch definition.
Was this the best bass ever in my listening room? I suppose the very top honours for value and performance for that would still have to go to Paradigm DSP-3200 subwoofer coupled with Paradigm’s Perfect Bass Kit possibly due to the calibrated and serial-numbered microphone that comes with the kit. However the set will cost me about $1,200 and that’s not a small change considering my PSB Subseries 300 is only slightly more than a year old. Still, the results here were mind bogglingly good, among the best ever. The overall effect was surprisingly natural be it a movie scene with synthesizer laden bass tracks or a concert recording that uses both acoustic, electric and synthesized bass.
Hello, David,
I purchased an Anti Mode 8033s-II unit several weeks ago and have found it to be a big help in eliminating the room modes in my A/V room. There is, however, a question that I have been wondering about when setting up the audio system prior to running the calibration sequence on the 8033. I found that changing the levels of my Parasound P7 preamp as well as the subwoofer each time I recalibrate the 8033, causes different filters to be active after each calibration is finished. I am also experiencing quite a bit of overloading of the unit causing the LEDs to flash. I have tried varying different calibration volume levels, but I still get LEDs to flash. I tried lowering the subwoofer input level on the P7, but I don’t like the overall results afterward.
My questions are:
What is your amp/sub volume setup for calibration?
Can you give me a ‘volume level ‘rule of thumb’ for setting up my 8033 calibration?
What about dealing with the input overload causing the LEDs to flash? Does it mean that the calibration volume levels were too high or too low?
I would appreciate any advice you can send my way in how to deal with these conditions.
Thanking you in advance for your time, David.
William Fehrenbach
I usually start with the volume level on the subwoofer to be at 12 o’clock. Then run the Antimode. Only then you run the calibration. If the overload light is on that means the input is too high.
Hi David,
Thank you for your reply. I’m still a bit confused. You said to start by setting the SW Vol control at 12 o’clock. Fine, we are talking ‘setup,’ but from there, you say ‘…then run the anti mode.’ Run it how? At that point we’re still in setup, and running the anti mode isn’t in the process yet. Then you say ‘Only then you run the calibration.’ I’m confused.
The way I normally do it is to: 1) set the SW volume, 2) set the amplifier to a normal listening level, and 3) simultaneously press and hold the 8033 bypass and lift buttons to start the calibration process. 4) Check the 8033 operation after the calibration is finished. All I have left to do at that point, is to possibly adjust the input level to the SW slightly higher to make up for the change in room mode loss.
Is this what you meant by ‘run the anti mode and check the LEDs for overloading?
Thanks,
William
Hi David,
need your advice with this Antimode 8033, my HT is in a small room – 3m x 4m, hearing boomy/muddy bass as my couch is against my rear wall. small room, therefore not much flexibility in my couch position. do you think this antimode device will be able to fit this?
Most definitely. Although it won’t give you sonic perfection, it will solve a lot of your room’s sonoc anomalies.