2015 Recommended Components Signal Processors

Signal Processors


BSG qøl Signal Completion Stage: $2395
The qøl Signal Completion Stage is a remote-controlled, solid-state signal processor with four pairs each of RCA and XLR analog inputs and two pairs each of RCA and XLR outputs. With the qøl activated, JA invariably noted a larger overall sound, with a greater impression of the ambience surrounding performers, increased image depth, and better layering within that depth. From JA's measurements, it appeared the qøl process is basically a variant of the well-known Blumlein Shuffler technique. "You must audition the effects of qøl yourself," he cautioned. Sold direct with a 30-day, money-back guarantee. (Vol.36 No.2 WWW)

DEQX PreMate D/A preamplifier/equalizer: $5995
In a field where, as KR puts it, "all automatic EQ systems conflate speaker correction with room correction," the DEQX PreMate stands out: In use, this DSP engine begins by measuring and analyzing the speakers—in exclusion of the listening room, to the greatest extent possible—then generates filters to correct frequency response, optimize time alignment, and, if desired, create a customized active crossover for that speaker. After that, the user can, if he or she wishes, completely discard the speakers' internal passive crossover components (although that's not required). Bass management and, ultimately, room correction can also be implemented with the PreMate: icing on the cake. The PreMate Incorporates a volume control and switches for choosing—or not—from three preprogrammed configurations. The usual variety of connectors provide S/PDIF, AES/EBU, TosLink, and USB inputs; there is also an XLR input for a calibrated mike (included), plus a variety of analog outputs, to use for the main stereo channels and subwoofers. Apart from noting that "the learning curve is steep," KR was unequivocal in his praise for the DEQX PreMate: "It made my very good speakers undeniably better, smoother and cleaner." (Vol.37 No.12 WWW)

Dirac room correction system: $850
Of course, the sound quality is dependent on the hardware in the system, says KR, but the acoustic transformation capabilities of DLRC are well beyond what is found built into most processors. Price is for full version; stereo version costs $499. (Vol.37 No.5 WWW)

DSPeaker Anti-Mode 2.0 Dual Core digital room equalizer: $1099
DSPeaker's Anti-Mode 2.0 Dual Core is a highly versatile, remote-controllable, two-channel room/system equalizer for full-range loudspeakers. It has two VS8053 IceDragon processor chips, a small color display, XLR and RCA analog inputs and outputs, a datalink connector for linking multiple Anti-Mode 2.0 units, and a USB connector for USB audio mode, firmware updates, and data downloads. By default, the Anti-Mode 2.0 measures and automatically corrects from 16 to 150Hz, but can be configured to work from 16Hz to an upper limit ranging from 80 to 500Hz. In addition, it provides a large array of filter and configuration options, and can store up to four different sound profiles. "The DSPeaker Anti-Mode 2.0 may be a small and unprepossessing black box, but its performance and power are huge," summed up KR. (Vol.35 No.11 WWW)

Paradigm PBK: $99 ✩
An adaption of the formidable Anthem Room Correction system used in Anthem's Statement D2 processor, the PBK includes USB cables and a microphone, and will work with up to four Paradigm subwoofers. While easier to use and considerably less expensive than either the SVSound or Audyssey devices, the PBK's subjective results were "no better or worse," said Kal. The PBK provided "a huge improvement" in the bass performance of the Paradigm Reference SUB 15, however. "The PBK, the SUB 15's obvious mate, is a bargain," KR concluded. (Vol.33 No.1 WWW)

Trinnov Magnitude Processor: $13,599 as reviewed
This digital audio processor includes Trinnov's powerful Optimizer room-correction software and has a modular architecture for customized arrays of inputs and outputs. The review sample was configured so that KR could feed it eight channels of balanced analog input and three S/PDIF digital inputs, and get from it eight channels of balanced analog output. The Optimizer measures each speaker's responses of frequency, phase, and impulse, and its relative volume level and distance from the calibration microphone; computes a digital filter set to correct for the frequency response, distance, and level of each speaker; and provides a 31-band graphic equalizer and level and delay controls for on-the-fly adjustments. Expensive but worth it, concluded Kal: "The superior abilities of Trinnov Audio's Optimizer to measure and equalize my surround system and correct for imperfect speaker placements were revelations." Replaced since review by basically identical Magnitude 32: 8 channels in/out (digital/analog), with calibrated microphone. (Vol.36 No.9 WWW)


DSPeaker Anti-Mode 8033C bass equalizer: $395 $$$ ✩
The Anti-Mode 8033C is a plug-and-play, DSP-based, single-channel bass equalizer with up to 24 Infinite Impulse Response digital filters. Its tiny chassis is powered by a 9V wall wart and has an RCA input jack and two RCA outputs. Kal noted tighter, cleaner low-end performance. "The DSPeaker Anti-Mode 8033 is a dandy little device for taking care of the major influences of room modes." Price includes shipping. The S version operate on stereo signals. (Vol.32 No.1 WWW)

miniDSP 10x10Hd: $599 $$$
Made in Hong Kong, the 10x10Hd has eight analog inputs and outputs (both balanced and unbalanced), and a stereo digital input and output (TosLink, S/PDIF, AES/EBU). It allows the user to set high- and low-pass filters for each output channel in increments of 1Hz; control gain, phase, delay, and compression for each channel; implement up to six parametric EQ filters per input and/or output channel; and select and store all options in up to four independent configuration presets. A simple front-panel push knob selects inputs and allows for nearly instantaneous A/B comparisons. Setup was simple and operation flawless. "The miniDSP 10x10Hd gave me the tools to do what I want in order to get the sound that I want," praised Kal. (Vol.37 No.1 WWW)

miniDSP nanoAVR 8x8 HDMI audio processor: $249
Taken to task by KR for its ungainly bass-management configuration—but nonetheless praised for offering real hands-on room EQ, like the miniDSP 10x10hd—the nanoAVR 8x8 now features reworked software and DSP firmware to allow standard bass management. (Registered owners of the previous version can download the update from the miniDSP website.) KR confirms that the changes address his criticisms: "I can now highly recommend the miniDSP nanoAVR 8x8 for use with high-end pre-pros that lack EQ or have limited or inadequate EQ." (Vol.37 Nos. 7 & 11 WWW)


Behringer DEQ2496: $524.99 $$$
Behringer's professional, rack-mount DEQ2496 offers a suite of signal-processing functions, including dynamic EQ, reverb, and digital room correction. It has AES/EBU and TosLink inputs but lacks a USB input. The sound was clear, fast, and lean, with good bass and dynamics, said JM. "If the idea of digital EQ doesn't make you run screaming from the room, the DEQ2496 is an amazing bargain, and might very well be the cheapest way to solve some problems in system matching or room acoustics," he decided. (Vol.35 No.4 WWW)

dalethorn's picture

Interesting that Digital Processors and Signal Processors are separate categories, given that I encounter the term 'DSP' (Digital Signal Processor) so often. Maybe it's a hardware-software thing.

corrective_unconscious's picture

The digital processors are DACs or things to route digital sound somewhere. There is some overlap if there's a CD player with inputs to its DAC, and some overlap with preamp/DACs, some of which of those might have some additional, secondary digital EQ functions.

The signal processors are mostly about varieties of digital EQ, with again a few hybrid products having some secondary functions.

The separation seems clear enough to me. It is the whole universe of modern audio which seems complex, i.e., the products themselves.

John Atkinson's picture
dalethorn wrote:
Interesting that Digital Processors and Signal Processors are separate categories, given that I encounter the term 'DSP' (Digital Signal Processor) so often.

The Digital Processors category is almost exclusively digital/analog converters. The Signal Processors category is reserved for things that do something to the signal and includes analog-domain processors, such as the BSG Q0L.

John Atkinson
Editor, Stereophile

dalethorn's picture

I'm going to profess a bit of ignorance here, so .... one of the places where DSP or some variant shows up in my world is related to music players such as built into the Pono device, or in computer software such as Foobar2000 etc. The great thing about EQ included in these players (or as plug-in software) is that the digital data gets EQ'd before it hits the DAC, so that whatever DAC or amp is used, the EQ remains constant in playback. Ignoring any negative impact on the EQ due to which peripherals are used, I've always assumed that EQ pre-applied to the digital data as described will reduce the resolution of the playback. If that's true, are there common analog EQ solutions that would provide better sound?

tdixon's picture

Does this mean there are no plans for an app being released like there were in previous years?

John Atkinson's picture
tdixon wrote:
Does this mean there are no plans for an app being released like there were in previous years?

Unfortunately, that's correct. No plans. However, this website reprint replaces the standalone free app.

John Atkinson
Editor, Stereophile

Dushyant's picture

From your comments prefacing the Recommended Loudspeakers 2015, I understand that category A (Full Range) has LF extension down to 20Hz. What about B (Full Range) and C (Full Range)? Do they also need to have LF extension down to 20Hz? If not, what is the LF extension for inclusion? For the restricted LF I assume that LF extension is to 40Hz for all categories. Clarification will be helpful and appreciated.


leesure's picture

Despite there being 25 Class A preamps, there are only 2 Class B preamplifiers (both from the same company) and NO class C Preamps? There are 18 Class A Power Amps and Zero Class C or D Power Amps? I thought, "Perhaps there are just no products that fit those categories any more. No more Adcom's. No more B&K's." But then I looked around and found that there ARE musically satisfying budget electronics.

So I am left to wonder...do they no longer submit their products for review or is Stereophile no longer interested in reviewing them?

I began reading Stereophile in my 20's when there was no way I could even consider a $10,000 amplifier. I aspired to a system like that, but also loved reading about gear that I could stretch to afford. I loved building a musically satisfying SYSTEM for well under $10,000. Had I only been able to read about the gear that was so far out of reach, I would likely have dropped the hobby altogether. Without the bridge, I would never have been able to get across to the ultimate destination. That bridge is being taken away from the next generation of Audiophiles.

I think that's a real shame.

Christopher Mankiewicz's picture

Kal, Please let me know. Thanks, Chris