3DsoundSurge Reviews: Klipsch ProMedia 2.1


	Mark Muschett puts Klipsch's ProMedia 2.1 to the test

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Klipsch ProMedia 2.1

Mark Muschett - Last updated April 20, 2001

Performance

Sound Levels

All about sound levels

Maximum sound pressure level, without subjective interpretation, is about quantity and is not necessarily reflective of quality. In this case we don’t have to address RMS and as we have noted many times before in other articles, RMS 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 speaker cones require more watts to deliver the same sound pressure level (dB) to your ears than other more efficient speaker cones.

If everyone measured maximum sound pressure level in a standard manner it would actually be a much more useful number than watts RMS when it comes to looking at multimedia systems. This is because unlike component hi-fi systems, it is highly unlikely that you will use the integrated amplifier with different speakers than provided with the system so you really only need to worry about integrated performance.

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 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.

It’s very important to note that these numbers do 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.

As usual we used a sound level meter to be able to test system 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. This is due to a number of reasons including the accuracy of the sound level meter. When we look at repeatability, the 1 kHz test tends to vary a bit between different tests.

To get some perspective on how loud the system is, I compare it to the numbers we got for the Cambridge SoundWorks Digital 2.1 ($100 2.1 system), Monsoon’s MM-1000 ($200 2.1 flat panel system) and VideoLogic’s Sirocco Spirit System ($250 2.0 system). The Spirit numbers are done in a different room than the other systems so while the numbers should be similar they are not totally comparable.

When in the normal seating position, using the standard 1 kHz test tone, the Spirit turned out to be the loudest of the four systems, 4 dB ahead of the ProMedia 2.1 and the MM-1000, both of which put out a peak SPL of 106 dB. Those systems were in turn, 6 dB ahead of the SoundWorks Digital 2.1.

That’s pretty good but we don’t listen to test tones so lets look at the real world test results.

Playing Rossini’s William Tell Overture with the sound meter 3 feet from the front resulted in peak sound pressure levels of 103 dB using the ProMedia 2.1, 1 dB ahead of the MM-1000, 3 dB ahead of the Spirit and 11 dB ahead of the much less expensive SoundWorks Digital 2.1.

Test Parameters

The sound level 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. I also did a test when the front speakers and subwoofer are 9 feet away which is a more typical movie set-up. We used a 1 kHz test tone, which is generally accepted for testing sound pressure, as well as a real world DVD test using the Fifth Element and a real world music test using Rossini's William Tell Overture.

For the music tests, all system tested had their subwoofers at normal listening levels and for DVD a bit above neutral where the system has subwoofer controls. For the 1 kHz test, the subwoofer of course does not matter. But for the music and DVD tests some units offers the ability for greater bass exaggeration using the subwoofer control. This type of exaggeration would result in higher sound levels that we get in our tests.

All sound level tests were done using an original Sound Blaster Live! with the windows mixer wave output set to maximum and the master volume just one notch below maximum. For the music test the peak sound pressure level is recorded where as for the DVD test we are only looking for the peak bass heavy effect. The results of those tests are summarized in the first and second tables below.

When playing a very bass heavy scene in a DVD movie (Fifth Element) I got the following results. The ProMedia 2.1 was again the loudest at 105 dB again only 1 dB ahead of the MM-1000 and 7dB ahead of both the Spirit and SoundWorks Digital 2.1. When it comes to a more traditional movie seating arrangement (9 feet from the front satellites and sub) the ProMedia 2.1 delivered a peak bass heavy sound pressure level of 99 dB. This put it yet again 1 dB ahead of the MM-100, 6 dB ahead of the SoundWorks Digital 2.1 and 12 dB ahead of the Spirit. The reason the level for the Spirit drops so much in this last test is because it does not use a subwoofer.

Looking back to the logarithmic nature of a dB, this means that at full volume the ProMedia 2.1 has a signal power 1.3 times stronger than the MM-1000 and 2 time stronger than the Sprit the music test at normal seating position. The Spirit is in turn 6.3 times stronger than the SoundWorks Digital 2.1 in the same music test. This means that the music test played back on ProMedia 2.1 is perceived to be 12% louder than when played back on the MM-1000, 20 percent louder than on the Spirit and 63% louder than on the SoundWorks Digital 2.1.

Our numbers above are not distortion free levels and at these reported levels there are varying degrees of distortion and no one should be driving their systems at full power levels for extend periods. Risk of damage aside, there is also sound quality.

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

Risk of damage aside, there is also sound quality. I don’t have first hand experience with the Spirit but Mikael noted in his review that he only had to reduce the Spirit by about 3-5 dB to maintain the very good quality. I had to reduce levels for the MM-1000 about 4-5 dB and the SoundWorks Digital 2.1 5 dB. I found I had to reduce the ProMedia 2.1 only by about 2-3 dB from full volume and that was just to maintain excellent quality, provided that the music was not overly bass heavy. That is, just as with the Spirit it was possible to push it much harder and still maintain good quality, particularly if you are not listening to test tones… One other bit worth noting is the sub can be exaggerated with good quality almost right to the maximum output levels for some sound effect and music but for other more constant bass heavy music or effects the sub can "burp" at higher output levels. All of the other subs tested with these types of music or effects were less than perfect at high output levels with the best performer being the HPM-4100 subwoofer. Overall the ProMedia 2.1 delivers more than enough very clean volume for desktop listening and even enough to fill a moderately large room with reasonably loud music. Considering the price of $179 that’s slightly better than what you might expect, offering slightly better volume overall than the identically priced Monsoon MM-1000 and somewhat more expensive Sirocco Spirit.

One other issue that is often more noticeable when pushing systems to the max is noise during quite parts of a movie or a song. Using a Philips Acoustic Edge, a Game Theater XP and the Terratec m3po which is a standalone MP3 player. I had no issues with hiss even at max volume and playing nothing when seated 1/2 foot away. With the Live I did have some hiss but based on past experience I should be able to eliminate that by moving the card to a different PCI slot. At this price point nothing less would be expected but given the early 2-v.2-400 hiss problems it’s something worth pointing out. Something else worth pointing out is systems with separate tweeters tend to be much more revealing of system noise.

1 Khz - this is a test of satellite response.

Distance to front (and sub)	ProMedia 2.1	Spirit	SW Digital 2.1	MM-1000
3 feet	106 dB	110 dB	100 dB	106 dB
9 feet	98 dB	102 dB	92 dB	102 dB

Music - Rossini - William Tell Overture - this is a multi-frequency test.

Distance to front (and sub)	ProMedia 2.1	Spirit	SW Digital 2.1	MM-1000
3 feet	103	100	92	102 dB
9 feet	96	90	86	94 dB

DVD Scene in Fifth Element
This is a multi-frequency test with emphasis on low end.

Distance to front (and sub)/rear speakers	ProMedia 2.1	Spirit	SW Digital 2.1	MM-1000
3 feet	105 dB	98 dB	98 dB	104 dB
9 feet	99 dB	89 dB	92 dB	98 dB

So the speakers are as loud as what?

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! Its definitely worth noting that when Mikael 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. He didn't check the meter the entire time but since it was the second time he saw the movie he checked at least most scenes with loud sound effects.

It's important to realize that in case of games the dynamic range is much more compressed and in a first person shooter like Quake 3 you will hit the max volume pretty much ever other second. This means that while it's fine for DVD movies to offer peaks of above 100 dB you will most likely get a headache if you use that volume setting for games. Music has better dynamic range than games but it is still much more often very close to the max volume. This again means playing music where the peaks go above 100 dB isn't exactly an enjoyable experience for most people as it will be more than the peaks that are very loud most of the time.

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On to the quality tests