3DsoundSurge Reviews: Altec Lansing ADA880


	Mikael Hagén puts Altec Lansing's ADA880 speaker system to the test

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ADA880 - Mikael Hagén - May 8, 2000

Sound level tests:

With 80 watts RMS of power, the ADA880 has specs that are ahead of both of the low cost Dolby Digital systems we reviewed last fall (Cambridge SoundWorks DTT2500 and VideoLogic Systems’ DigiTheatre) but behind MidiLand's new $300 (estimated street price) S4-8200 Dolby Digital system. It’s also significantly below many other higher priced DD 5.1 systems. If we look at systems that don't include a Dolby Digital decoder then it’s also well behind Klipsch’s 4-speaker system, the Promedia, which has specs of 400 watts RMS.

Watts (RMS), however, doesn’t always tell the true story about the loudness since the speaker cone efficiency can vary quite a bit between two systems. That is, some cones requires more RMS to deliver the same dB to your ears than other more efficient speaker cones. This is something that was clearly shown in our Crossfire and ACS56 review as well as our Crossfire vs. ProMedia comparison article. As usual we used a sound level meter to be able to test their loudness with more than a simple "they are loud" or "they are not so loud" statement.

While using this sound level meter is better than just using ears and memory to compare the speaker system's loudness it's not 100% accurate and especially the 1 kHz tends to vary a bit between different tests. The results of these tests are given in Decibel (dB), which is a unit of measurement commonly used for intensities of sound or sound pressure. This is a logarithmic unit defined so that an increase of 1 dB represents multiplication in signal power (what the speaker produces) of 1.258 or sound pressure (what your ears hear) increase of 1.122. When you place both yourself and the speakers in air the logarithmic scale of sound intensity and sound pressure can be considered identical.

The sound pressure meter was positioned where my head would be positioned when I am at the PC playing games. This means 3 feet away from the front speakers and 3 feet from the rear speakers. I also did a test when the front speakers and subwoofer are 9 feet away and the rear speakers about 3 feet away, which is a more typical movie set-up. I used a 1 kHz test tone, which is generally accepted for testing sound pressure as well as some real world DVD tests using the Fifth Element and a real world music test using Rossini’s William Tell Overture. The results of those tests are summarized in the first and second tables below. All sound level tests were done using an original Sound Blaster Live! with the windows mixer wav output set to maximum and the master volume just one notch below maximum. The DVD tests are of course done in Dolby Digital 5.1 mode. For reference I compared the volume to the Cambridge Soundworks DTT2500 digital system and VideoLogic Systems’ DigiTheatre.

The ADA880 put out a peak SPL of 104dB dB using the 1 kHz test tone where as the DTT2500 put out a peak SPL of 98 dB and the DigiTheatre 105 dB. In the music test the ADA880 achieved 102 dB and DigiTheatre 101 dB. The music test was never used for the DTT2500 but Mark tried it in a different room with his DTT2500 and got 99 dB. In the DVD test ADA880 managed to reach an impressive 107 dB, clearly ahead of the DTT2500’s 102 dB but slightly behind the DigiTheatre’s 108 dB.

Looking back to the logarithmic nature of a dB, this means that at full volume the ADA880 has a sound level or signal power that is 3 times stronger than the DTT2500 when playing the DVD movie. This however does not correspond directly to the perception of loudness. We generally perceive loudness to be doubled when the intensity increases by a factor of 10. This corresponds to a 10 dB increase which for example means that DVD test is perceived to be 30% louder on the ADA880 than on the DTT2500. The obvious conclusion is of course that ADA880 is almost on par with DigiTheatre and well ahead of the DTT2500 when it comes to loudness. One other interesting thing to note is that the ADA880 actually offered the same volume when I tested 9 feet away from the front channels and subwoofer as when I was 3 feet away from the front channels and subwoofer in the DVD test. I did an additional test that showed the reason was not the rear speaker volume. The only conclusion I can come up with is that it’s because the ADA880 shakes my room in a way none of the other speakers manage. Your results may be different and you will also notice a clear difference if you decrease the bass level.

When you try to push a speaker system to the maximum, distortion will usually become a problem. Distortion, when used in the context of sound, is defined as a change in the waveform of a signal during processing, often caused by the signal level being too high for the hardware or software that is processing it. Something to keep in mind is distortion is a fact of life when it comes to sound reproduction. The higher quality something is, the lower the distortion is going to be at normal operating levels. Pushing the system to its maximum will result in higher levels of distortion and it's at this stage where what is acceptable will depend for the most part on three factors. First, you don't want to push the system so hard that you damage it. The next two are personal as its your ears and your tolerance as distortion starts long before your system sounds like its going to blow up! With respect to the ADA880, when playing DVD movies I had to lower it about 3 dB for the ADA880 which was about the same as for the DigiTheatre, where as with the DTT2500 I had to decrease the volume about 5 dB.

1 kHz test tone - no subwoofer response at this frequency so this is a test of satellite output alone.

Distance to front (and sub)/rear speakers	ADA880	DigiTheatre	DTT2500
3 feet	104 dB	105 dB	98
9 feet and rear off	96 dB	96 dB	90

Rossini William Tell Overture - this is a test of combined subwoofer and satellite response.

Distance to front (and sub)/rear speakers	ADA880	DigiTheatre	DTT2500
3 feet	102 dB	101 dB	99 dB
9 feet (DTT2500 7 feet) and rear off	100 dB	96 dB	93 dB

DVD Scene in The Fifth Element - this is mostly a low-frequency test

Distance to front (and sub)/rear speakers	ADA880	DigiTheatre	DTT2500
3 feet	107 dB	108 dB	102 dB
9 feet and 3 feet	107 dB	103 dB	98 dB

For a little more perspective, a typical conversation is 65 dB, a loud orchestra is 80 dB, unsafe levels start at 90 dB, thunder is around 109 dB, a rock concert is 110 dB and the pain threshold is around 130 dB. U.S. Department of Labor regulations set permissible noise exposure to 105 dB at no more than 1 hour per day! Can also be interesting to know that when I watched Star Wars: Episode 1 in a movie theater that featured Dolby Digital–Surround EXand THX the sound level meter rarely went above 100 dB even during the action scenes and never past 105 dB. I didn't check the meter the entire time but since it was the second time I saw the movie I checked at least most scenes with loud sound effects.

The loudness tests noted above, with the exception of the DVD tests, were done with the soundcard connected to the ADA880 in analog stereo mode. Choosing Pro Logic mode on a stereo source decreases the volume by about 1-2 dB. Using the digital connection gives almost the exact the same result and I couldn’t notice any difference in audio quality either. Important to note that this is only when the ADA880 is at max volume. If you have the volume control at 50% the digital is much louder for some odd reason. I used the Live for all tests other soundcards/devices may show a difference between analog and digital as the internal electrical "noise" level of a PC can vary quite significantly from PC to PC and even within a given PC!

Back to the installation

So on to the sound quality tests