which of these a/v receivers is the best? onkyo tx-sr606, denon avr-1909, or a sony str-dg920?

Agree with the responders that say Sony receivers are crapola.

I calibrate audio systems with a 24th octave rig as part of my work. In your price range, I would chose in this order for my own personal use:

1. Yamaha RX-V line of receivers

2. Denon

3. Onkyo

Just stay away from Sony all together, Sony receivers are pure crap. They are underpowered, cheaply built, and overpriced. And if you are a beginner to av gear, I highly doubt you need pre-outs. Pre-outs are used when you want to connect an external power amp instead of using the receiver's internal amplification.

Denon and Onkyo on the other hand are both quality brands. I disagree with the guy saying Onkyo is "trying to become the new Denon or Yamaha". Onkyo has been around for decades, so I think they know what they're doing.

You really can't go wrong with Denon or Onkyo. Both of those receivers have pretty much the same specs. The Onkyo will probably sound a bit "brighter" and the Denon will probably sound a bit"warmer". Some people prefer one or the other, its a matter of opinion. But they both sound great. I have the Onkyo 606 myself and it's a great receiver. The sound is crisp and detailed. I will say that you will probably be able to find the Onkyo cheaper than the Denon, so my vote goes to Onkyo just because of the value. But like I said, you really can't go wrong.

For a beginner - you have some good choices there.

Sony - the "ES" Series of receivers are quite good, but Sony makes hundreds of lower end receivers and few of them stand out as being very good.

Denon has a great reputation and I could argue that it is 'the best' because of build quality, performance in music with demanding audiophile quality speakers.

But Onkyo TX-SR series of receivers have been quietly impressing a lot of people and made some "Best of" and "Editor Choice" lists last year. Nobody is praising the sound - but the number of features, connections and ease of use for budget prices has impressed a lot of magazines and people.

Onkyo is trying to become the new Denon or Yamaha so you get a lot of value for the money with the TX-SR receivers.

Let me suggest you decide this way:

If you are trying to put together a good music system with audiophile speakers, strongly consider the Denon unit.

If you are putting together a system for TV, Movies, Gameing, etc., where pure audiophile music is not the main focus - consider the Onkyo unit.

I say do the Sony. Here's why: First of all, at Crutchfield.com, it's on sale $449.99 w/ free shipping. It does 4 HDMI switching & has pre-outs for all channels. I like that flexibility b/c when you need more power, you only need to find some external amps w/o having to replace the whole unit. I have a Yamaha RX-V663 and I have the new Tru-HD surround & I say it's awesome! Anyway, The Denon model you mentioned is made in China. The others aren't. The Onkyo is also on sale there, but it doesn't have pre-outs & I would reject it solely for that reason. The Sony model would have BRAVIA Sync with the new Blu-ray players that are available. The BDP-S350 from Sony I have seen at Amazon for $219. This allows both units to talk to each other and do all kinds of auto calibration & switching. Plus you'd only need one remote for them both. Get a Sony 1080p TV & you'd be the man! G'luck!