Will bridging a 4 channel increase distortion compared a 2 channel amp?

[momofx 10+ year member]

I was wondering if bridging a 4 channel 100w x 4 amp to get 200w rms x 2 will noticably increase the noise floor and distortion level compared to just getting a 2 channel amp rated at 200w rms x 2?

In simple terms will hissing noises, etc. be more apparent if I use the 4 channel and bridge it?

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[DARKHART 10+ year member]

On most quality built amps with properly set gains, you shouldn't notice anything unless it's in the recording itself...

 

[momofx 10+ year member]

Ok so I exprimented with this today on my Precision 900.4 amp that runs the mids. When I connected the mids in regular unbridged mode, I could tell there was a loss in power BUT it sure as hell did not sound like it lost half power (???) more like just a little loss in regular unbridged mode. The most interesting thing is I noticed is that the stereo seperation sounded more "defined" - it was like the clarity of the music went to a whole different level and although I cannot really explain how it sounded, lets say I really like how much better the sound quality is now and yes the noise floor did go down.

Just my actual 2c from experimenting... anyone else had this experience when bridging and running regular unbridged for mids / highs. System is 4 way active btw...

 

[n2audio 5,000+ posts]

From something really low to something slightly higher, but still really low.

There's a little bit of a gray area.

If you look at a thd vs output chart you generally see thd going down as power goes up - UNTIL the amp's power supply gets stretched out -- then it shoots from ~0.1% to 1% where the measurement is taken.

There are some old amp reviews on carsound.com's old review pages that show a lot of really good test charts, and they all follow roughly the same pattern.

The Kenwood KAC-929 for example - 460w rms -- has THD measurements of 0.05% at 2w steadily decreasing to 0.01% at 400w, then jumping up to right about 0.10% at 500w and about 530 or so at 1%.

All things considered -- if you're pushing an amp to its limit (clipping) you're going to get distortion, if you dont, you won't -- bridged or not.