Distortion

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 sound like its going to blow up! With both of these systems its more likely the volume will blow your ears up before the systems themselves go awry but there is still a clear difference between the two. Klipsch does not offer specifications for Total Harmonic Distortion so as noted before we will assume their maximum output is at the 10 percent THD. Videologic supplies numbers which are very impressive, noting that at 80 Watts RMS there is only 1% THD where as pushing the system right up to 100 Watts RMS results the same 10% THD that we will assume for the ProMedias.). Videologic also notes that at nominal listening levels the THD for the Sirocco Crossfires is a paltry less than 0.01 % THD. It’s worth noting that according to Yamaha better than 2% THD is really rather uninteresting since the human ear won't be able to tell the difference. So what about real world testing?

Again these tests are using the same Windows mixer settings noted above. With the original preamp the ProMedia satellites started to sound harsh beyond 75 percent power with some distortion and clipping in satellites. If you crank the subwoofer levels up even more at that point there is the occasional slight distortion in bass and it does get booming at higher levels. To maintain the excellent quality with the original preamp the ProMedia volume levels needed to be set to no more than 75 percent. With the new gain modified preamp that all ProMedia units are shipping with, the system can pretty much run at full volume for many source materials with very acceptable levels of distortion. This is where I will draw my conclusion about the new gain modified preamp not actually having a significant impact on ProMedia performance. The performance that was lost with the switch was only there for bragging rights (that some will miss), it was never usable because of the clipping and harsh sound beyond 75 percent. By giving up that distorted high end, Klipsch has reduced hiss (see below) while delivering effectively the same usable top end as before.

When it comes to the Crossfire I have the same experience as Mikael, that is I had to decrease the volume about 3 dB below maximum to maintain the excellent quality the speaker system offers. Having said that, I found that the Crossfire satellites at full volume are much cleaner than the ProMedia with the original preamp at full volume and about as clean (there is some very minor clipping at maximum sound and near maximum in the windows mixer) as the gain modified ProMedia at full volume. This is despite the fact that the Crossfires are pumping quite a bit more volume at that level!

Neither subwoofer is particularly susceptible to distortion but if you go for extreme levels that no one is likely to use (full volume, with subwoofer attenuation beyond the default) the Crossfire sub would start to rattle. This was very likely the sub hitting the end-stops which never happens at normal sub levels at full volume or even at 75 percent volume and 75 percent sub levels. The ProMedia subwoofer was much more immune to such abuse.

Noise

If you have been following the ProMedias you may know that their one possible Achilles heel was hiss. This hiss is a result of combining a high-gain preamplifier with high-efficiency tweeters. I for one never found the hiss to be a big issue, but it was enough on an issue for some other listeners that Klipsch first offered a gain modified (or gain reduced) replacement preamp. Then in a move to quell all complaints they made a rolling change to permanently implement the gain modified preamp into the design. As I noted in the full review, I had no issues with hiss at volumes of up to 50 percent with no sounds playing and with the new low gain preamp I can revise that number to 75 percent and even at maximum volume its not terrible but definitely noticeable. This is important as when watching movies and listening to music as there will be times when there will be silence or near silence.

When it comes to the Crossfire, with no sounds playing there is even less hiss than the ProMedia. At normal, or even loud, listening levels you will have to be very noise sensitive (and have your PC in a sound proof box) to have any issue with the Crossfires noise with no sounds playing. While you can hear it at 100 percent (again with no sounds playing) its very acceptable considering the insane sound pressure levels you will be subjecting yourself to at full volume.

Considering that you usually have sounds coming from your speakers, the high sound pressure levels that you will be subjecting yourself to on both systems to hear hiss when there is silence may accelerate hiss becoming a permanent non-issue to your ears ;). Overall, with the gain modified preamp installed, differing noise levels are to my ears not a significant factor when comparing these two systems, especially if you don’t run them at maximum levels.

Abit SP50

Altec Lansing ACS 56

Altec Lansing ACS 54

Altec Lansing ADA880 Dolby Digital

Altec Lansing ATP3

Boston Acoustics BA4800

Boston Acoustics BA7500

Cambridge Soundworks FPS1000

Cambridge SoundWorks FPS2000 digital

Cambridge SoundWorks 2.1 Digital

Cambridge SoundWorks DeskTop Theater 5.1 DTT2500

Cambridge SoundWorks DeskTop Theater 5.1 DTT3500

Cambridge SoundWorks MegaWorks 510D

Diamond Audio Technology ProMedia 3205

Klipsch ProMedia 2.1

Klipsch ProMedia 4.1

Klipsch ProMedia 5.1 Initial Review

Labtec APX 4620 Review

Labtec Edge-418 Flat Panel

Labtec's LCS-2514

Logitech SoundMan Xtrusio DSR-100

Logitech Z-560 Initial Review

MidiLand MLi-490

MidiLand S4-7100

MidiLand S4-7100 Plus

Monsoon MM-1000

Monsoon MM-2000

Philips MMS305 4.1 Initial Review

Polk Audio AMR-150

Polk Audio AMR-130

Videologic Sirocco

Videologic Sirocco Pro

Videologic DigiTheatre 5.1

VideoLogic DigiTheatre DTS

Videologic Sirocco Crossfire