Product name: DSPeaker Anti-Mode 2.0 - sound processor
Manufacturer: DSPeaker (VLSI Solution) - Finland
Approx. cost: 1200$-900€ (YMMV)
Reviewer: Lucio Cadeddu - TNT Italy
Test sample kindly supplied by: AV Solutions
Reviewed: March, 2014
DSPeaker (VLSI Solution) is a small hi-tech company located in Hervanta (Finland), a suburb of Tampere, which is sometimes referred to as the Silicon Valley of Finland, because of the concentration of high tech companies in that area. It might be interesting to recall that the world's first-ever GSM phone call was made right in Hervanta back in 1991, when Radiolinja was building its first GSM network. Nokia, Intel and many other companies have offices in Hervanta as well.
The DSPpeaker Company specializes in digital elaboration of audio signals. More precisely they design devices that, via DSP, can correct room acoustics and fix speaker/room interactions problems. The principle is rather simple: test signals are reproduced by the speakers and then room sound is picked up via a sophisticated microphone. The built-in Anti-Mode software analyzes the sound and modifies the signal so that the frequency response at the listening seat is as flat as possible. You might be aware of the fact that room acoustics can sometimes introduce peaks (and dips) that exceed 10dB at certain frequencies, mainly in the bass and low-midrange area.
The internal software (Anti-Mode 2.0, the name speaks for itself) is an evolution of the former, already popular Anti-Mode algorithm. "Dual Core", in this case, refers to the use of 2 x VS8053 IceDragon processors. The unit offers XLR and RCA analog inputs/outputs; digital audio (TosLink S/PDIF) input/output, a USB connector for PC audio and a datalink connector for using multiple Anti-Mode's. An easy to use graphical menu is displayed on a small color screen. Everything can be managed by a small and easy to use remote. Of course the measurement microphone is supplied as well.
The DSPeaker processor is very versatile, since it can also be used as a DAC, as a high quality digital-stepped pre-amp with remote controlled volume, as a 16-bands parametric equalizer and much more! You can connect it between your preamp and power amp (or inside the tape loop of an integrated amp): this way the sound gets digitalized via its internal ADC processors, processed in the digital domain and then converted again into analog. But you can also use it between a digital transport (or a PC) and an amplifier, and you can also let it process the digital signal (once room-corrected) by your favourite DAC. Moreover, you can use it between a digital transport and a power amp. This way you exploit all the capabilities of the unit: room DSP, DAC and digital preamp at the same time...and you avoid double A/D - D/A conversion. You can visit the official site for the full list of different connection possibilities.
Of course, the processor works best with full-range systems (or satellite + subwoofer combos) because the worst effects of speaker/room interaction occour in the region of low bass. If you use mini-monitors perhaps you don't need the services the DSPeaker can deliver. Small woofers interact mildly with poor room acoustics, and this is the main reason why many audiophile seem to prefer them.
The DSPeaker processor is very easy and intuitive to use. Just choose your favourite connection (between pre/power amp, tape loop, as DAC/processor etc.) and start the calibration process. Place the supplied microphone in a safe and firm place at your ears' height and wait for the frequency sweeps to measure the response of your room and find the right calibration. Once done, the processor displays the room response (in red) and the corrected response (in black).
If peaks and dips are high (resp. deep) and narrow the processor doesn't try to fix them. It just makes peaks and dips smoother. Actually, boosting a dip isn't generally a good idea, because you're effectively forcing amplifier power and loudspeakers into a sonic black hole. Less severe variations are smoothened in an amazingly precise way and the in-room response becomes very flat, if not ruler-flat.
The optimal frequency limit of the correction is automatic: the device decides the limits basing its decision on detected room response. You can decide to perform a custom measurement (NOT correction, though), defining your range: bass (16-200Hz), bass-midrange (16-500 Hz) or even full-range (20-20kHz). Generally, the processor corrects just the bass range, from 16 to 150 Hz but it can be custom adjusted up to 500Hz. This is sufficient for most applications. Indeed, room acoustics problems in the mid-high range can be easily corrected with the use of absorbent materials. However, to cure bass problems you need huge bass traps.
The result of a flatter frequency response in the bass might lead to a lack of bass frequencies, because the ears were used to the boost generated by resonances. Once these have been cancelled by the processor you might feel something is lacking. If that's the case you can tilt the bass response up as you like (there are many ways to do this with the DSPpeaker). It should be remarked that many recordings have little bass because they rely on generic bass boost generated by the listening room. This explains why a ruler flat bass response might sometimes sound too dry to our ears.
Using the DSPeaker between preamp and power amp (or on an integrated amp tape loop) lets you exploit the benefits of the correction with every source of your HiFi system. The price to pay is a double A/D - D/A conversion which, as far as it seemed to my ears, doesn't add distortion or tonal artifacts. Generally, it seems my system sounds a bit less airy and emotionally involving when the double A/D - D/A is active though it might be a by-product of the cleaner and more controlled bass range.
Bass articulation improves, though bass weight seems to decrease. As said, you can correct this by means of the various customizable EQs and tilts. Of course, since the DSPeaker cures bass problems you can focus your attention on setting up the speakers for best imaging and mid-high range tonal balance, instead of spending countless hours trying to find the perfect compromise between depth of the image and bass range balance. This is really good news for us.
In the screenshot above you can see the corrected response (in black), while the uncorrected room response is the red graph. Intentionally I've haven't tried to get the best placement of speakers/listening point because I wanted to see what the DSP system could do with a bad room response. As you can see the narrow dip at 60 Hz is left almost as is by the correction, for the reasons explained above. There's a slight boost from 20 to 30 Hz, and a decrease of five/six peaks which aren't too severe. On worst sounding rooms (I've seen horrible graphs on other listening rooms) the effects of the correction might be more visible and, hence, audible :-)
It should be remarked that my speakers have a claimed frequency response which is flat at 20 Hz, for this reason the measurements above make sense. This can be quite different using bass-limited loudspeakers.
Rear connections! Coaxial S/PDIF in/outs are missing, for example! And analog in/outs aren't up to audiophile standards: because they are too close together you may have a problem when using beefy RCA plugs. Generally, all the connections are too close one to the other...a slightly larger cabinet would cure this problem. The tiny microphone is not easy to keep firmly in place. Some kind of physical support should be supplied. A WiFi/Bluetooth option could improve the interface of the device with a PC, a notebook or, even better, a smartphone. The device should offer the possibility to work as a SPL meter. The digital inputs accept signals at 44.1, 48 or 96 kHz sample rates and up to 24bit resolution, perhaps a high-resolution 24/192 option should be included as well.
This is a really amazing piece of gear. Considering how expensive the first DSP processors were (and we reviewed some of them in the past, including Sigtech and Z-Systems) this DSPeaker appears to be extremely affordable, considering its almost infinite features and customizable options. If you add that it can work both as USB/toslink DAC and minimalist digital preamp, this little magic box is a jewel. The DSPeaker is a must-have if you have a full range system and a listening room with serious bass problems. Generally, it solves most of the bass problems so that you are no longer forced to use obtrusive and ugly bass traps, which are normally not welcomed in living rooms (right?). In my opinion, a real bargain and an extremely well-engineered product.
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