Parasound AVC-2500 Audio-Video Controller.

Manufacturer: Parasound Products, Inc., 950 Battery St., San Francisco, CA 94111; 415/ 397-7100; www.parasound.com

Price: $3,495

Source: Manufacturer loan

Reviewer: Howard Ferstler

The AVC-2500 is Parasound's entry into the "super" surround-processor sweepstakes that currently includes units produced by Lexicon, Meridian, Adcom, B&K, Krell, Rotel, Citation, and Theta, among others, as well as by more mainstream outfits such as Yamaha and Onkyo, who include them as part of their upscale integrated amps and receivers. As such, the Parasound sits near the financial middle of this rather price-diversified group.

Unlike nearly all of its competition, however, the AVC-2500 also contains a tuner (outwardly it is technically a tuner/preamp, even though it has no phono preamp on board), and unlike some of them, it is also THX Ultra-certified.

Also unlike most of the competition, the processor has only one special mode for dealing with musical program material (appropriately named Music) and only two ways to deal with Dolby Surround, Dolby Digital, and DTS movie and music program sources: "basic" decoding and THX-Ultra, both subsumed under the unit's Cinema mode.

The Parasound unit also lacks the extrachannel embellishments found on some Yamaha, Lexicon, and other-brand products. Instead, the AVC-2500 merely has the usual five-channel outputs: left, center, right, left surround, and right surround, plus connections for two subwoofers. The latter get identical mono-sub signals, however, and not a stereo feed.

When Cinema is selected, the unit will automatically select proper decoding for Dolby Digital, DTS, or Dolby Surround inputs. If Cinema is selected when standard, two-channel stereo program material is being listened to, the Dolby Pro Logic decoding mode is automatically accessed and L+R signals are steered to the center channel and L-minus-R material (or at least identical signals that are detected at +90 degrees in one channel and -90 degrees in the other) is steered to the surround-channel speakers.

Other modes include two-channel Stereo, Mono, and Party. The latter sends stereo signals to the front speakers and also to the surround speakers, in a kind of "dual-stereo" arrangement that works well for, um, parties. These modes will work with all input sources: PCM stereo, DTS, Dolby Surround, and Dolby Digital, downmixing each as required.

In spite of its rather basic functions for Dolby Surround, Dolby Digital, DTS, and basic music playback, the unit comes with a raft of nifty other features. These include 24-bit processing, automatic level and speaker-distance calibration (using a supplied, outboard microphone), auto A/V input selection, auto A/D overload protection, assignable digital inputs and surround modes, two component-video inputs (plus one output), six analog A/V inputs, six analog audio-only inputs, eight digital-audio inputs (each of which can be also configured for A/V use), ramp-up volume level after turn on, on-screen displays for video users, user-choice name option for each input, illuminated remote control, dual-zone sound delivery for remote locations, and an RS-232 control port for computer-integrated systems.

As I noted previously, one interesting thing the AVC-2500 does not have is a phono preamp. If you want to go that route, you have to obtain an outboard unit and plug it into one of the two-channel analog inputs. I would imagine that Parasound's own P/PH-100 ($120) would be more than adequate for this job.

The unit also does not have a built-in RF demodulator for Dolby Digital laserdisc use (this is a format that is essentially finished, but many individuals will still have DD laserdisc collections), but Parasound does have one available that can plug into a special RF input on the AVC-2500.

Finally, if you have a 5.1-channel outboard decoder or player with an on-board decoder (here, we are talking about DVD-A, mainly, because you would not need an outboard decoder for DD and DTS work) and you want to plug it into the AVC-2500, you will almost certainly need the optional, VC-1 volume control card upgrade. Without it, those inputs normally bypass the master volume control. The cost of the upgrade is $200.

The fit and finish of the unit is excellent, with gold-plated connectors on the back and a front panel that is clean and business-oriented. In addition to a power switch (and Parasound makes a point of noting that you best shut the unit down with the switch, rather than using a remote on/off control), there is a Surround-selector button, a Digital-input button, a tuner-Preset button, and a Source-selector button. Hitting any of these buttons immediately but temporarily converts the unit's volume-control knob into something else. Indicator lights let you know which override function has been chosen. The volume control itself is a continuous-rotation device that can go round and round as the level changes are indicated on the front panel in 1 dB increments.

There are six other, smaller buttons above the bigger ones: Zone (which allows for remote-system control from the front panel), THX (which engages the THX-Ultra circuitry in the Cinema mode), Memory (used for assigning input names and radio presets), Mute, FM/AM, and Tuning (which activates the tuner section in the auto or manual modes).

As noted, the AVC-2500 can handle a large number of advanced inputs. Indeed, there are 93 connections on the back panel (!) and these include six analog audio and six analog audio/video. The latter include S-Video and composite-video connections, and you can also assign either of the three-jack component inputs to any of the audio/ video inputs. The unit's eight digital-audio inputs can be assigned to any of the other inputs, and include four coaxial, two Toslink, one AES/EBU, and the RF demodulator input. You can also use the remote control to assign customized names to these assorted inputs.

Tuner antenna/cable connections include the usual AM screws, plus a 75-ohm hookup for FM. A 300-ohm/75-ohm converter is included, as is a 300-ohm dipole antenna wire.

The remote control is a "learning" type that allows the user to operate a raft of other components, besides the AVC-2500. The remote is critical, because you need it to do the set up and it also makes it much faster to operate some functions than the frontpanel controls can manage. Indeed, once you have the unit plugged in and set up you do not need to touch the front panel again at all.

The remote is battery-powered; the owner's manual indicates that when changing batteries you make sure to get the job done inside of three minutes. This keeps the user-installed commands from being deleted. I should note that the supplied manual had no instructions on how to load the batteries into the remote, so I will tell you here that you pull the lock latch toward the hinged cover and not away from it. Once open, it is easy to beat the three-minute deadline. The remote also has a backlight feature for use when the listening/viewing room is dark.

The microphone used in conjunction with the set-up functions will need to have its lengthy cable temporarily plugged into the processor's front panel, with the capsule itself located at the listening position. The microphone's job is to detect signals generated by the AVC-2500 during its initial set-up procedure, allowing the processor to configure itself for your speakers and their arrangement.

I did this, and found the procedure to be both entertaining and functional. Specific signals are generated at each channel and the microphone pickup allows the processor to set optimum levels. You can still easily adjust the set-up levels manually if you disagree with the processor's findings.

The microphone can also be used to calibrate the system to account for varying distances to the speakers. With the mike in the same location, you command the processor to adjust for distances, and it generates a series of signals at each channel in turn, and then sets its own internal delays accordingly.

I should point out here that the manual had no instructions about how to load the battery in the powered microphone. The thing simply unscrews in the middle into two parts and from there it is easy to see how the battery goes.

Earlier versions of the AVC-2500 had only one subwoofer crossover-point option and that was the THX-mandated one at 80 Hz. The current version being tested here has several other options that might make the unit work better with some non-THX speakers, particularly if the satellites are full-range jobs that have better bass extension than THX left, center, and right speakers.

While some of those crossover options might be attractive to a few users, I think that the 80-Hz default setting will generally work just fine. It has a 24 dB/octave rolloff for the low-pass section and a 12 dB/octave roll off for the high-pass section, which complements typical small-sized satellite speakers. As with all other subwoofer hook-ups I know of, you will need some kind of SPL meter and test disc (I suggest the Delos Surround Spectacular test set, DE-3179) to properly evaluate the crossover options.

Movie buffs will almost always choose Cinema for movies, and as I noted above, Cinema will automatically decode program material requiring DD, DTS, and DPL processing. A front-panel indicator light will note which type of program material is being decoded. Straight Cinema provides no embellishments, beyond what the mixing engineers at the studio put into the material. However, at the push of the THX button, these sources will be given the usual THX treatment.

That treatment includes re-equalization for the front channels to tame the brightness found on many movie soundtracks (particularly some of the older ones), timbre matching (which matches up the sound of THX-certified surround speakers to more closely mimic the response uniformity of THX-certified front speakers), and adaptive decorrelation.

The latter is "adaptive," because with standard Dolby matrixed program material, the circuitry takes the monophonic surround channel and simulates a kind of stereo effect with it for better spaciousness and envelopment. With DD and DTS material, this synthesizing only takes place if the surround track is mono or if there are occasional mono components. If the surround sound track is stereo (typical with newer movies), the adaptive-decorrelation circuitry does nothing.

Now, there are some DTS and DD music programs showing up these days (the DTS versions may be DVD material or they may be compact discs that have no video at all), and so in some cases the Cinema mode should also be used for those. Indeed, with something like the James Taylor Live at the Beacon Theater DVD (done in Dolby Digital at 448 kbps), Cinema works just fine. In most cases, you would leave the THX option turned off, because it tends to subdue the highs too much with music program material.

I should point out that the owner's manual notes (and I concur) that some DTS musical program sources are encoded in such a way that there might be excessive bass when they are played in the Cinema mode. For such material, they suggest using the Music mode. Interestingly, one music DVD that fared best in the Cinema mode was the Eagles Hell Freezes Over release. For some reason, it was bass-balanced as if it were a movie program.

Now, the Music mode is what a lot of you compact-disc music lovers are going to be mainly interested in, and it stands in stark contrast to processors made by outfits such as Lexicon and Yamaha, which have a veritable multitude of emendations available for enhancing assorted, two-channel music program sources.

With this kind material, the Music mode appears to extract L-minus-R information, delays it a bit, and sends it to the surround channels after a touch of manipulation to give it additional spaciousness. It also appears to slightly reverberate the left- and right-front channel material. Because of this, it does not overly fabricate additional reverb that might muddy up the effect somewhat. However, the effect also is program-dependent, and so with some recordings it might not be as workable as what we get from more complex processors.

The Music mode also sums the L+R material up front and sends it to the center channel. Unlike what we have with Dolby Pro Logic, or what Lexicon does with its Music Logic function, or what Yamaha does with its Classical/Opera function, the AVC-2500's L+R center signals are not deleted from the left and right channels and "steered" to the center. Instead, the L+R material also remains in the left and right main channels as a phantom image, and the center feed is simply a L+R blend, additionally supplied to the center speaker at a somewhat reduced level.

Now, Dolby Pro Logic, center-channel steering usually works OK with Delby Surround program material that has been specifically configured to work within the limitations of steering. However, with program material that has not been so configured (and this includes the bulk of two-channel music recorded today), it has the potential to cause problems.

For example, some steering circuits may have trouble stabilizing images at half-left and half-right locations. Usually, this will be no big deal, but at times it can be. In addition, with certain steering systems, the soundstage delivered by two-channel sources can end up being laterally compressed toward the center to an unacceptable degree. Often this can be corrected by simply backing off the center level by a couple of dB, but that can be tedious and you have to remember to reset the center level for movies or 5-channel music programs. And of course, if the center speaker is not as good as the left and right mains, or is positioned too high or too low, even good steering will not work to proper effect.

Consequently, steering is a mixed bag. With good steering (as with what we have with the Lexicon's Music Logic function), two-channel program material can often be reformatted to almost simulate what we would hear if the program had been originally recorded in three channels across the front. The effect can be sensational, particularly if centered soloists are involved and/or the listener is seated some distance from the centered sweet spot.

Nevertheless, because the AVC-2500 does not use center steering with the Music mode, it bypasses the problems inherent in less stellar steering systems. The imaging is more stable from the sweet spot, and there is no chance of a center collapse.

Of course, this kind of processing has shortcomings of its own. We will have both a "solid" center channel and a "phantom" center working at the same time, and so there is the potential for comb-filtering interactions and the like. What kind of gets us off the hook with the AVC-2500 is that the center level employed by the Music mode is not set as high as what we have with some steered systems, thereby minimizing the negative interactions. Unfortunately, because of this the sound stage will not remain as well centered when listening from off-axis.

With two-channel program material, whatever kind of up-front manipulations are chosen to improve the soundstaging will involve compromises of some kind. Some people will prefer the compromises incorporated into the AVC-2500 and others will prefer the more radical approach.

Now, the Music mode can also be used with 5- or 5.1-channel program material, and as I noted previously, this is what Parasound recommends for DTS music sources. The main difference you will hear will involve bass levels with DTS software. With Dolby Digital program material the sound should be pretty much the same in the Cinema and Music modes, unless you operate Cinema with the THX emendations engaged. With Dolby Surround music material (such as what Delos has been producing lately), you can pretty much choose which of the three modes work best for you: Cinema, THX-modified Cinema, or Music.

If this sounds overly complex, remember that the Yamaha DSP-A1 I use in my reference system has dozens of music-surround and movie-surround options that might drive some users bonkers. Indeed, for music there are only about four modes I choose from and for movies I generally have two that work well for me. More soundfields do not automatically mean better performance.

Before listening to music with the AVC2500, I did try out some test signals from the Avia test DVD (available from Ovation software) and from the Delos Surround Spectacular test CD (DE-3179). The Avia disc has a raft of Dolby Digital tests, and the AVC-2500 had no problem with any of them, as one might expect from a top-class Dolby Digital processor. The THX emendations were also effective, and believe it or not the timbre-matching function did manage to make front-to-rear pans work more effectively. The Music mode sounded just like Cinema with DD program material test signals that included pink-noise pans and ambiance "clicks" to check imaging.

Things were a bit different with the Delos test CD, which you will remember is encoded in standard, two-channel matrixed Dolby Surround that can be decoded down to four channels by a Pro Logic decoder. When the processor's own on-board DAC was dealing with a digital input coming from either of my DVD players, there were some anomalies present that I did not hear when I used either player's analog outputs and fed them to the analog inputs of the AVC-2500.

The Delos disc has a series of Dolby Surround-coded ambiance "clicks" that move from channel to channel, and with a digital input the Parasound unit was vague and just could not consistently position the clicks. This was in contrast to my Yamaha DSP-A1, also with digital inputs that its on-board DAC had to deal with. The Yamaha located each click sequence precisely where it was supposed to be.

The Delos disc also has a series of left, half-left, center, half-right, and right pink-noise pulses, and again the AVC-2500 had problems with them when its digital decoder had to deal with the PCM digital inputs from either DVD player. The pulses were randomly clipped during the initial part of the signal. In contrast, the DSP-A1's on-board DAC handled these pulses in its usual championship way.

I should note that these signals are killers and in no way will they generally mimic how recorded music or PCM stereo movie program material would ordinarily be delivered. With musical sources, the AVC-2500 and its on-board DAC delivered the goods in championship style, and I kind of believe that the reason that the processor had problems with those special test tones at least partially involved its fade-in/fade-out feature, which prevents an abrupt input signal from blasting the listener. That would explain why it worked just fine with music but had problems with killer test signals.

Interestingly, if I switched to the analog inputs from those two DVD players, the problems with the pink-noise pulses and ambiance clicks disappeared completely, with the processor dealing with them as well as the Yamaha processor did. This makes me wonder if the fade-in/fade-out feature was the entire culprit with the digital inputs, because the feature also works with analog source material. The problem appears to be related to the interface between the AVC-2500's DAC' and the outputs of the two players, but as I noted above, it did not impact musical performance at all that I could determine.

I also tried the Delos disc's ambiance clicks with the analog inputs, but with the processor operating in the Music mode. In this case, input clicks in the left and right channels resulted in slightly reverberated clicks in those same left and right channels (but not the center), plus delayed and reverberated clicks in the surround channels at a somewhat lower level than what we had in the left and right. Clicks in the center resulted in no reverb at all. Clicks in the surround channel (remember, this is a test disc done in Dolby Surround, and so there is only a single, L-minus-R surround channel) resulted in clicks again showing up in the front left and right channels, plus the surround channel, but in this case the latter was louder than the left and right fronts.

The amount of reverb delivered in this mode was in stark contrast to the often very powerful reverberation delivered by the Yamaha DSP-A1 in some of its hall, nightclub, and church modes, although all of the Yamaha's standard DSP simulations (those not based upon basic, Dolby Pro Logic) allowed for no click reverb at all with those out-of-phase clicks for the surround channel. This is because when faced with out-of-phase sources, a sizable chunk of the reverb the Yamaha supplies to the surround channels is generated by the processor and not laid over existing out-of-phase reverb.

In contrast, the AVC-2500 uses the existing reverberation on the recording, and routes it to the left, right, left-surround, and right-surround channels, with a bit of a delay and possibly some additional reverb. Both processes have their strong points, and which one works best will nearly always be determined by the recordings themselves, in addition to the way the speakers and the listening room interact. The advantage the Parasound has is that it does not actually embellish the reverb that already exists on the recording. The advantage the Yamaha has lies in its huge number of reverb-choice options and its adjustability.

But what about its real-world performance in dealing with music? I had a chance to try out the AVC-2500 with several excellent music recordings, and I can say without question that it did an excellent job with virtually all of them.

One of those included a new Delos release of the complete Bach Brandenburg Concertos (DE-3185). The AVC-2500 did as good a job in stereo as one could expect, but it was downright spectacular in its Music mode. The Yamaha DSP-A1's Classical/ Opera mode resulted in a larger-scale sound, but the Parasound probably did a better job of simulating the kind of environment where these works would normally be performed.

The Cinema mode also worked well with this program material, but its stronger center feed tended to narrow the soundstage a bit and it benefited from backing off the center level about -3 dB. I felt that Cinema worked better for music than Music if one was listening some distance away from the sweet spot. The THX emendations helped to diffuse the ambiance better when using Cinema, but there was some dulling of the ensemble up front, due to the THX re-equalization applied.

Other releases were the Shostakovich Symphony Number 8 (Delos De-3204), Rameau's Pieces de Clavecin (Reference Recordings RR-27CD), as well as my trusty Engineer's Choice disc (Delos DE-3512). In each of these presentations, the AVC-2500 did an exemplary job. The sometimes too-well-etched Rameau material sounded excellent with the AVC-2500's THX-amended Cinema setting, provided the center level was backed off about -3 dB to minimize center squeezing.

While my Yamaha DSP-A1 was sometimes better sounding with certain program material, at other times I would give the edge to the Parasound. Indeed, with centered vocalists and the listener also centered, the Parasound's Music mode nearly always sounded better balanced, and I believe that anyone who is put off by synthesized ambiance and still likes the sound of clean two-channel audio will prefer the Music mode's subtle embellishments to anything the Yamaha can come up with.

I also listened to a number of Dolby Digital and DTS musical programs, such as the aforementioned James Taylor Live At the Beacon Theater (DD DVD), as well as Sting's Brand New Day and Ten Summoner's (DTS compact disc). I also gave the 1812 Overture on the Delos Surround Spectacular Dolby Digital DVD a try. In each case, the AVC-2500 did an exemplary job of handling this program material, even though the Sting album has some rather gimmicky surround tricks and lacks a genuine center feed. With any of the DTS music discs I tried, you also had to experiment to see whether Cinema or Music would deliver the best bass balance.

Finally, I should note that I did, indeed, crank up the FM tuner section of the processor, and it did a fine job of dealing with the radio program material in my area. The presets were easy to set up and the overall tuner quality was probably superior to most of the transmitter-limited source material.

Overall, I believe the AVC-2500 is worth its cost, particularly if the user is not particularly enamored of the sometimes heavy-handed approach that other surround processors deliver when they work with two-channel program material. In some ways, super processors such as the Yamaha DSP-A1 and Lexicon DC-1 offer more workable options. However, exercising those options can be a chore for some people and there is little doubt in my mind that many music lovers will prefer what the AVC-2500 can do to enhance the enjoyment of two-channel program material.

As for movie use? Well, this is a THX-Ultra certified surround processor. What else need I say? -- HF