With 62.5 watts of power the DigiTheatre has specs that are just slightly behind the DTT2500 and significantly below many other higher priced DD 5.1 systems and way behind Klipsch’s 4-speaker system, Promedia, that have a specs of 400 watts RMS. Using a sound level meter I was 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. A Decibel (dB) 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 sound level or signal power of 1.258.

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, more typical movie set-up. I used two different wave files, an 1 kHz test tone and pink noise, both of which are generally accepted for testing sound pressure levels. This will alleviate the problem of differing loudness at different frequency levels. The 1 kHz test tone was from the same audio test CD that I tested the subwoofer response with and the pink noise was generated using the demo version of Cool Edit from Syntrillium. The results of those tests are summarized in the first and second tables below.

For reference I compared the volume to the Cambridge Soundworks DTT2500 digital system.

The DigiTheatre put out a peak SPL of 105dB dB using the 1 kHz test tone and 100 dB for the pink noise where as the DTT2500 put out a peak SPL of 98 dB and 101 dB respectively. The obvious conclusion is of course that DigiTheatre can produce much stronger midrange than the DTT2500 while low frequencies they are about equal but it only seems to apply for stereo sound. When playing a very bass heavy scene in a DVD movie (The fifth Element) I got as high as 108dB using the DigiTheatre while the DTT2500 only reached 102dB.

Looking back to the logarithmic nature of a dB this means that at full volume the DigiTheatre has a sound level or signal power of 5 times stronger than the DTT2500 when playing back the 1 kHz test tone but actually slightly less when playing the pink noise. 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 1 kHz test tone is perceived to be 50% louder on the DigiTheatre than on the DTT2500.

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!

The loudness tested above are when the soundcard is connected to the decoder in analog stereo mode and small speaker mode and the amplifier is in 4-speaker mode, that is the front channels is duplicated to the rear channels. If using the large speaker mode the pink noise test goes down 3dB to 97dB, 1 kHz remains the same. Choosing ProLogic mode on a stereo source decrease the volume with 2 dB on the pink noise test and 8 dB on the 1 kHz test tone. Connecting directly to the amplifier for 4-speaker gaming gives almost exactly the same score as the scores in the table. Using the digital connection gave almost exact the same result and couldn’t notice any difference in audio quality either. I used the Live for all tests other soundcards/devices may show a difference between analog and digital. In case of connecting to a computer the amount of noise can differ significantly.

Now loudness isn’t everything. In fact it’s not even the most important, as sound quality is much more important. There is a tendency for people to associate quality with volume and in fact louder often does sound better. However, to compare systems of differing power, you should do you best to compare at the same or similar volumes. Testing in this manner showed that the DigiTheatre exhibits great frequency response, significantly better  than the DTT2500 right across the full 50-20,000 Hz range. This is especially true of the two-way front satellites delivers great sound quality from rather low (lower than the specs 180 Hz) frequencies all the way up to 20 kHz, most likely thanks to the 2 inch tweeter / 4 inch woofer driver combination. The rear speakers has the same frequency spec (180 Hz to 20 kHz) and while still quite good, e.g. better than the DTT2500 satellites, doesn’t offer the same quality as the front speakers. For most sounds there is not much of a difference but for music with a lot of high frequencies it’s a noticeable difference. Having said that I found the rear speakers to be well matched to the front speakers when playing DVD movies.

The center satellite offers about the same quality as the rear but with slightly better low frequency response, just like the specs 140 Hz indicates. The subwoofer delivers good bass and delivers on its frequency response of 50-200 Hz when tested using the same audio test CD we use on all our speaker reviews.

Music

When you play music you can choose either Pro Logic or stereo on your decoder, in both cases you can choose if you wish to send all bass frequencies to the front speakers or not. The subwoofer will still be active in each mode but slightly more so when you choose to filter away the low frequencies from the front speakers. Choosing stereo will make the rear and center silent unless you change the mode of the amplifier from ac-3 mode to stereo in which case the front channels will be duplicated to the rears and the center will be silent. The ProLogic mode will take advantage of the fact that many regular stereo recordings contain natural ambience that a Pro Logic decoder will treat much like surround sound. If you choose the ProLogic mode when playing such recordings, the DigiTheatre’s will give you what many find to be a pleasant surround-like effect, while others find it to be annoying noise from the rear satellites. Choosing the Dolby Prologic mode will as previously mentioned reduce the volume quite a bit. Dolby Prologic will of course work much better if the music has Dolby Surround encoded, which is true of many movie soundtracks.

No matter the mode you select the system shows excellent quality for all types of music with good bass and excellent midrange and high frequencies thanks to the excellent two way front speakers. The difference is quite significant compared to the DTT2500 that I'm currently testing, especially when it includes a lot of instruments with more high frequencies like classical music while for pop music the difference is less noticeable.   When it comes to loudness for music the DigiTheatre system easily fills a medium size room with loud music but if you want to leave the room and go to the kitchen and still here loud sound the DigiTheatre doesn’t deliver what you want, the same is true if you intend to fill a rather large room.

Games

For games you have three options you use the speakers as a 2.1 system, as a Dolby Prologic system or as 4-speaker system.

Gaming as 2.1 system

When used as 2.1 system and you choose the bass options (that is filter the low frequencies from the front satellites and send them to the subwoofer) the system offers great bass. The subwoofer isn’t as active as when watching DVD movies and compared to many multimedia speaker systems (e.g. DTT2500), the DigiTheatre system uses the subwoofer less and depends more on the satellites. The result is not as deep rumbling bass but a more distinct one.

The imaging is also excellent, that is 3D sound works quite well on 2-speakers. However other than for the effects of above and below, you simply can not beat the 3d audio experience of a four-speaker system with a single two speaker system.

Gaming as 4-speaker system

As mentioned in the installation part you can use this system as a 4-speaker system. Now this is not something VideoLogic recommends, as unlike the DTT2500, the DigiTheatre is designed primarily as a DD 5.1 system and not as 4-speaker gaming system but we still had to try it.

The problem with using it as a 4-speaker system is that no signal will be directly sent to the subwoofer. The subwoofer will not be completely inactive since the system will automatically send some (just as much as when you choose not to filter away low bass frequencies when you connect to the decoder) of the bass frequencies that goes to the front right and left to the subwoofer but it will for some reason not do the same that goes to the rear. In addition to that, the front satellites produce a lot louder sound for lower frequencies than the rear speakers. I did some tests of this and when sending a 180 Hz signal (the low-end specs for both) to the front and then to the rear give almost exactly the same result. Going lower to 150 Hz again produce the same result but below that there starts to be a huge difference. For example, at 100 Hz the difference is a quite significant 20 dB, that is the perception of 4 times as loud for front as rear. If you take a test with the pink noise that includes both some low frequencies and also some higher frequencies what you hear is not a difference in loudness but a difference of bass where the rear is lacking bass.

When testing in games the difference is less noticeable, most likely because most games don’t have much very low frequencies (other than gun fire and explosions) but you will still hear a difference. I also found that it works differently depending on the soundcard you use. With a Live or any 4-speaker card that uses Sensaura’s 3D technology it works like above, while with the cards using Qsound’s 3D technology the difference is even less noticeable because some of the sound coming from behind is also sent to the front (don’t ask me why J ). The Vortex2 cards don’t seem to bother placing low frequencies so there is significantly less difference between front and rear.

When playing games you will not think much of the difference, not even with the Live, but compared to in 2-speaker mode you will be lacking bass. It’s not horrible in anyway but doesn’t give you the rumbling and room shaking sound effects it could if the subwoofer was used more.

A few new soundcards have a subwoofer output and may turn the DigiTheatre into an excellent 4-speaker gaming system but the only one I have failed to work as a 4-speaker soundcard at all. It has nothing to do with the DigiTheatre, it’s either a broken card or a driver conflict.

Dolby ProLogic games and Live!Surround

You can also use the system as Pro Logic system with games that support it (e.g. Unreal Tournament, most Electronic Arts games and many console games). I tried Dolby Surround in a few games (including Turok, Unreal and Expendable) and found it to a good step-up from stereo but far behind 3D sound with 4 speakers. It depends a lot on the game though and e.g. UT is much better than Unreal and not that far behind.

If you have a Live card you can also use the Live!Surround option. This is a feature Creative uses to allow owners of surround systems that doesn't have a separate in for the rear channels to still be able to use them, but then only mono in rear and limited frequency response (100 Hz - 7 kHz). You will also lose all HRTF processing on the rear. If you don’t have a clue what HRTF is the short explanation is it’s what the 3D sound companies use to create 3D sound with headphones and 2 speakers. For 4-speakers it improves the positioning between the speakers and also makes elevation cues (sound above and below you) possible. So the lack of HRTF on the rears will mean no elevation sound cues for sound behind you and sound between the front and rear speakers will not be placed as well as when in 4-speaker mode. The lack of stereo will of course mean no way of knowing if it’s slightly to the rear right or rear left.

The front will still have HRTF processing and also the benefit of using the center speaker for better in front placement. Note that the Vortex 2 doesn’t have any HRTF processing on the rear speakers but the better HRTF on the front compared to the Live makes up for it a bit. The Vortex2 of course has stereo in the rear so clearly better than this Live!Surround mode.

While in theory the lack of stereo in the rear means 2-speaker 3D sound offers better sound cues than the Live!Surround mode in practice the sound from behind is now much more convincing and for that reason I still think this is a lot better than just using 2-speakers. I can also say that Live!Surround in Unreal is a significant improvement compared to Dolby Surround in that game. The sound effects are clearly better when using 3D sound compared to the Dolby Surround option and the rockets passing by me sound significantly better in Live!Surround mode than in Dolby Surround. Note that the "flying by" feeling is even stronger when using stereo in the rear. In Unreal Tournament the difference is less noticeable.

Now when using the ProLogic mode the subwoofer will work well even when explosion happens behind you but because the limited frequency response for rear channels (starts at 100 Hz) you will still here a clear difference between explosions behind you compared to in front of you.

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