Home Theater Equipment Review

December 1999

NAD T770 Surround Sound Receiver

NAD is one of those companies with a long-term reputation for producing solid entry-level high-end components. Their products, especially integrated amplifiers and CD players, have been recommended and re-recommended over the years from a variety of high-end authorities. NAD’s philosophy has long been "design here, build there." This gives them an ability to design what they believe sounds better and has the requisite features, while taking advantage of lower-cost assembly and parts sourcing. The result is usually components with a calm, purposeful appearance compared with those marketed by more familiar mass-market companies. The T770 continues the tradition with a simple but functional front panel and low-key charcoal gray paint. With no money spent on flashy looks or displays, NAD is able to put more money into the sonic performance of their products, and it shows.

Features

NAD’s T770 is a 5.1 A/V receiver with built-in Dolby Pro Logic, Dolby Digital 5.1 and NAD’s proprietary EARS (Enhanced Ambience Recovery System) surround system for two-channel music or video soundtracks.The five channels of amplification all offer 70Wpc. These aren't the usual weak "receiver watts" which are about half as powerful as "real" watts either. You get 70 real watts, which is plenty of power for most rooms when easy-to-drive speakers are used. Digital inputs are TosLink or coax. A single digital cable from your DVD player adds surround-sound capability to your system. There are two coax digital inputs, one for laserdisc AC-3 RF and one for DVD PCM digital. None of the sources is labeled laserdisc or DVD, leaving the owner to decide how to apportion out Video 1 through Video 5. All of the video inputs and outputs have both composite and S-Video connections. There are no component inputs or outputs on the T770. The T770 offers a number of other features that are described or listed later.

The AM/FM tuner section meets any reasonable performance expectations. There are 40 station presets that can be assigned to any combination of AM or FM stations.

I do not live in an area possessing anything extraordinary in the way of AM or FM broadcast quality or selection. Our choices are limited to a couple of overly predictable college stations, NPR and the terrible assortment of corporate programmed stations. Under these circumstances, the NAD pulled in everything I would expect it to. They all sounded as well as can be expected for stations putting out compressed signals which sound like a typical $99 CD player with reduced channel separation to improve the signal to noise ratio. In my location, I don’t consider FM or AM serious or critical music sources, and I would presume that the majority of you don’t either. I had no problems with or complaints about the NAD tuner section.

Remote control

The NAD’s infrared remote is not backlit, so using it successfully in a dark room requires a week or so of memorization. Volume, mute, power, and surround mode selectors are easy to find with or without light. The setup menu keys also make it easy to select, navigate, or make menu changes without the use of room lights. The NAD remote also has keys for a NAD CD player and for a NAD cassette deck.

Surround processing

I used the NAD receiver as a "pre-pro" (preamp and surround processor) with five channels of external amplification and found the surround results to be quite good. The results were equal to the results from separate surround processors that are within a few hundred dollars of the NAD’s price. Frankly, this level of performance in a receiver surprised me. I’m used to A/V receivers giving a little less in the way of sound quality when compared with good external surround processors. When compared with other receivers, the T770’s surround performance is definitely in the "A" category. The only way to do better is to purchase a more expensive standalone processor.

I only used the digital input for a DVD player while assessing surround-sound processing. However, I did take time to experiment with different digital cables and found that, yet again, the digital cable makes an inexplicable difference in sound quality. Once more, the evergreen Cardas Lightning Digital/Video cable produced the best digital sound quality by a wide margin. But at $269/meter, the Lightning is not likely to be found connected to many NAD receivers. My other choices all sounded duller, flatter and kind of boring. In this case, not even Steve Rochlin’s $50 Enjoy the Music digital cable woke up the sound as it did when connected to the bargain 24/96 MSB Link DAC.

Speaker setup allows for the selection of "large" or "small" for the three front channels and "on" or "off" for center, surrounds and LFE subwoofer. Level adjustments go from +12 dB to –12 dB, a generous range that ought to encompass almost any combination of loudspeakers. The test tone can be run in automatic mode that progresses a little too fast to measure with an SPL meter. The other option is to manually send the tone to any one speaker for as long as you want it there; you adjust the level of the manually selected speaker with buttons on the remote. It is quite easy to perform from the listening position.

On the same menu, NAD managed both to annoy me and to make me very happy. It used to be that you had to tell the processor how much delay to crank in for various speakers, which requires you to measure speaker distances to the listening position then calculate or use a lookup table to determine the optimum delay setting. The delay settings were in milliseconds -- Greek to most people. NAD does away with that. You just enter the distance each speaker is from the listener and the delays are set internally to the correct value. That’s great, but it is also annoying that you cannot set the distance from the listener to the surrounds to be greater than the distance from the main speakers to the listener. NAD’s manual claims this is not a problem since surround speakers are almost always equal to or closer than the main speakers. Huh? Setup instructions for other processors say that having the surround speakers farther from the listener than the main speakers is the most common setup condition and they emphasize the importance of measuring correctly to get the right delays. In fact, in some surround systems where on-wall or in-wall speakers are used, NAD’s menus will not allow you to set the right amount of delay for the surrounds. In my system, the main speakers are about 8.5 feet from the listener and the surrounds are 10 feet from the listener (mounted on the wall, where they were designed to be). However, please keep in mind that by no means is this a massive problem that should deter anyone from going for the T770. After all, there are many surround systems in which the surrounds are equal to or closer than the main speakers.

Additionally, any speaker that is connected with the "small" option turned on is also subject to having the extra high pass (low cut) crossover inserted in its circuit. Of course, this reduces the quality a bit when you turn on the LFE channel (see sidebar left). You’re stuck with this unwanted Dolby Digital artifact unless you avoid the use of both LFE and "small" speaker settings in surround processors and receivers, or you wait until Dolby Digital improves the chip set to make these filters less destructive to the sound quality.

The audible effects of the insertion of the extra crossover circuit is a loss of clarity and detail through the mids and highs. Cymbals lose some realism. Stringed instruments are less pretty-sounding and less harmonically rich. The general transparency of the system suffers as well. The sound is distinctly "grayer", which means more electronic and less natural. When no speakers are set to "small" and when the LFE is set to "off," all of these sonic artifacts disappear and Dolby Digital becomes a distinctly better-sounding surround-sound format.

NAD’s EARS mode

I tried out NAD’s EARS surround mode using two-channel music CDs and was delighted with the result. In fact, if I owned the NAD T770, I would not often listen to music in stereo. The EARS system was unobtrusive and natural. I would have to continuously go back to stereo mode to remind myself of the subtle enhancement that EARS provides. NAD exercised restraint in using the rear channels as ambience-recovery channels. You are never startled by sounds in the rear channel when using EARS; there is only consistent low-key ambience sound in the rear speakers. This opens up the listening room a little, freeing you from the obvious sense of room boundaries. The center channel is used for "center fill" in the EARS mode. This is not a radical use of the center channel; it’s just a filling in of the stereo phantom image. EARS also uses the LFE sub (if one is connected). Because of the implementation of the LFE sub, sound quality is compromised when LFE is "on" (see sidebar). I found EARS with LFE "off" was quite pleasing. But be warned, shortcomings in the quality of sound from the center-channel loudspeaker will become very obvious. Only very good quality center-channel loudspeakers will be enjoyable for music. In addition, if the center channel is not a very good match for the left and right (and surrounds for that matter), the mismatch will be obvious when using EARS for high-quality music playback.

Amplification

When pressed into full-bore A/V-receiver duty, the five NAD amplifier channels produced more performance surprises. Far from the "noise maker" amplification channels found in low-cost A/V receivers, the amplifiers in the NAD T770 offer some highly enjoyable sound. Everything from two-channel CDs to surround movies sounded better than just "good" on the NAD. In fact, the sound was very much what I expect from entry-level solid-state amplifiers, but don’t often receive. The sound is clean, easy to listen to, and able to capture your attention and imagination for extended music listening and movie watching. Most surprisingly, the T770 was able to induce bliss when listening to music, unlike any receiver I’ve experienced in the past. Bliss is that elusive state you enter when the sound quality reaches a certain plateau that allows you to completely forget the hardware and live in the music itself. This is not an easy feat. I’ve had $10,000 tube amps fail the "bliss test" along with solid-state and tube components at many price points. You can only pass the "bliss test" when everything is just right and somehow, with all the complexity that has to go inside one box to create an A/V receiver, NAD has managed to do it in the T770.

In an absolute sense, the NAD’s amplification is no threat to the $1495 Belles 150A Hot Rod stereo amp, but compared with other moderately priced integrated amps and receivers, the NAD T770 is very competitive or better-sounding. This is the hallmark of well-established and well-hit design goals. I was surprised that the T770 was able to produce sound this good in a full A/V receiver package. Those who doubt that a receiver can reproduce a convincing illusion of depth, width, and height need to hear good loudspeakers setup with the T770 -- the soundstage illusion is quite good and was yet another surprise during this evaluation. What surprised me the most was how quickly I was able to forget that I wasn’t listening to the big-rig theater setup. Thirty minutes into The Mummy I had completely forgotten that I was listening to a theater setup with a retail price of less than one third of the "big rig." That is a rather stunning accomplishment. I’m not saying there is no difference, only that it is easy to accommodate yourself to the T770-based system and get a thorough kick out of movies with great soundtracks.

Setup and sound quality improvements

Some owners of A/V receivers may think that their equipment is "not good enough" to justify setup esoterica (and there are also people who just don't believe in it). Isolation bases, better "feet" and power-line conditioning may seem superfluous at first glance, but the results I got with the NAD T770 proved to me that A/V receivers are just as sensitive to setup and benefit just as much from attention to setup details.

Aiding the ultimate sound quality I was able to wring from the NAD T770, I used a home-brew isolation base made of an inner tube on top of my rack’s top shelf with another heavy shelf board on top of the inner tube. Low pressure in the inner tube provides a pseudo-isolation base that does indeed improve the sound of this receiver as much as it improves the sound of other high-end audio components. In addition, I used Nordost Pulsar Points in aluminum for feet ($100 for four), which produced another nice incremental improvement in sound quality. Finally, the receiver was plugged into VansEvers’ $275 clean line jr. Model 11 Analog single-outlet power-line conditioner for yet another incremental sound quality improvement. When selecting a PLC for use with a five-channel A/V receiver, it is essential to select one with no possibility of current limiting. The clean line jr. Model 11 Analog is about the least expensive PLC I know of that can provide all the current a five-channel A/V receiver can deliver with no worries about current limiting. The very inexpensive Nordost Flat 2 speaker cables revealed this excellent soundstage performance almost as well as the slightly more expensive JPS Labs Untraconductor up front with the very moderately priced JPS Labs Super Blue bulk wire for the surround channels.