I've read this thread from beginning to end. The one thing that sticks out is that you need this to fix that, pre-amp to boost this, lowering db's to justify that, and on and on. I really want a great pair of matched speakers, prefer a matched sub-woofer, without needing to patch hissing, unbalanced, etc. These will probably be the last quality speakers I will own, wanting something that works near perfectly with my Omen, through a 3.5 jack. I was ready to strike on these, ease in a sub-woofer, and be a happy camper. Maybe these aren't what I am looking for. Any comments, please?
chuck1252Shortly: No you do not need pre amp
Why:
These are active (powered) speakers. They feature 40w class D amp themselves. You do not need preamplifier (or discrete amplifier) to drive these. They also have gain setting at the back +4dBu & -10dBV. +4dBu is "pro-audio" line level standard and you may want to use this setting if you have very good source (DAC, RIAA, etc). -10dBv is meant for consumer devices or just devices not capable of standard line levels (computer integrated dacs, mobile phones and so on) . Find out how "hot" your source is and select correct setting.
Hiss may or may not be an issue. Real answer is: it depends. How much noise your preamp has? How about your power lines? Ground loops? You never know if you never try. Typically more devices close to each other mean more noise. Higher gain settings (-10dBV) tend to bring hiss more audible easier. Notice that +4dBu is LESS gain than -10dBV (because signal has to be amplified more).
To solve most hiss problems is to use these as balanced. It should minimize most background humms and decrease overall noise level. However to take advantage of the balanced inputs you must have balanced source (XLR or TRS jack most commonly).
Further reading:
Line level - https://en.wikipedia.org/wiki/Line_level
Balanced audio - https://en.wikipedia.org/wiki/Balanced_audio & visualised http://www.songsofthecosmos.com/images/balanced_line.gif
Ground loops - https://en.wikipedia.org/wiki/Ground_loop_(electricity)
chuck1252The problems seem intimidating but their solutions are actually very simple. E. g. flip the -10dBu switch, or plug your speakers into a power strip which is using a different outlet than your DAC. Any problems this speaker might have involving hissing are the same problems any other active speaker would have in the same scenario. In my opinion, these speakers are plug and play.
RaymondblPlugging the speakers into a different outlet than the DAC makes zero sense if it's a ground loop issue. A ground loop is created from two things in the audio chain on two different ground points which results in voltage drop between the two grounds and that causes the hum.