Hey guys

[Critical Bill]

I am using an Arcam AVR300 and love the sound. Ample power, clean, no complaints at all. BUT.... I keep hearing that that receiver REALLY comes to life when you bi-amp it using the internal settings. PROBLEM, I can't do it, no speaker capability and I don't (as of now) want to replace the speakers.

I am debating getting an Emotiva XPA 3 and just using the Arcam as the pre-pro. Of course I shouldn't be messing with any of it because it does sound great after all. That's just not how it works though is it? UPGRADITIS has got me. My question is this:

The Arcam puts out a real 100 watts (high current) all channels driven for HT and 120 X 2 for stereo. THe Emo puts out 300 X 3 into the same 4 ohm load. It also boasts 400 X 2 for stereo (4 ohm).

Should this make a noticeable difference in my HT and music listening experience? I am really looking for the extra bottom end with my mains. I know they can do it because I often use them with a 1973 Marantz 2230 and they absolutely sing! It's really comical how vastly the Arcam outperforms other receivers that I have had AND how vastly the Marantz outperforms everything else I've heard for 2 channel ( including my Arcam).

Am I just crazy in thinking that the Emotiva XPA 3 should give me the best of both worlds when paired with my Arcam?

[Zing]

Should this make a noticeable difference in my HT and music listening experience?

I would be more than a little surprised if you noticed any difference at all.

95% of the time, you're using less than 30 watts. Of the remaining 5%, I'd venture to guess that 3% would increase your power requirements to 60 watts and the last 2% of the time you might need 120 watts.

Looking at it mathematically, and let's assume your speakers' efficiency is 85dB, it would only take 64 watts to achieve 104dB SPL (whoch is pretty darn loud). Subtract a few dB for your distance; add a few dB for the other speaker(s) and it all adds up to an unnecessary expense.

If you just want to temporarily cure your upgraditis bug, knock yourself out. But I think there are better ways to spend upgrade money.

[m-fine]

95% of the time, you're using less than 30 watts. Of the remaining 5%, I'd venture to guess that 3% would increase your power requirements to 60 watts and the last 2% of the time you might need 120 watts.

I would say that over 90% of the time you try to watch a movie at reference you will need more than 120 watts to avoid clipping. With a sensitivity of 91 db per watt at 1 m, if you are sitting 4 meters back you will need 500 watts for a reference max 105 db peak. Even a 100 db peak will use over 120 watts so the soundtrack does not need to hit max levels to tax your amp. Most people are using speakers with a lower sensitivity, although many sit a little closer then 4 meters.

You can argue that the peaks only represent a small portion of the soundtrack, but clipping in the middle of a movie or song is still clipping.

Looking at it mathematically, and let's assume your speakers' efficiency is 85dB, it would only take 64 watts to achieve 104dB SPL (whoch is pretty darn loud).

Assuming you are only 2 meters back, about 6.5 feet, the math works out to 256 watts not 64. Not too many people sit within 1 meter of their speakers except for a desktop/office system like what Gizmo is perfect for.

[Zing]

Assuming you are only 2 meters back, about 6.5 feet, the math works out to 256 watts not 64.

I was speaking in real world terms but you're talking theoretical specifics. And that's OK, so let me be a bit more specific.

First of all, using your 91dB 1w/1m example, that translates to 84dB 1w/2m and therefore theoretically requires 128 watts to achieve 105dB at the listening position, not 256. However, that's the math for just one speaker in anechoic conditions. Add a second speaker in a real world room, factor in boundary reinforcement from the surfaces in that room, and you'll realistically reach those 105dB peaks somewhere around 85 watts (85.34 watts to be precise).

Secondly, I believe you're making the assumption based on a full range audio signal. In the real world, where most people have a powered subwoofer talking care of the bottom few octaves, the power requirements for the rest of the spectrum will be reduced exponentially. It doesn't take anywhere near 85 watts to get 10kHz cranked up to 105dB at a 6 foot distance. However, it would indeed require a great deal more than 85 watts to reach that level with a 35Hz signal.

Lastly, you're right, clipping is never a good thing regardless of its duration. But as I understand it, clipping has almost nothing to do with an amplifier running out of power but it has everything to do with an amplifier running out of voltage. A poorly designed, cheaply-made 500w amp will clip long before a well-designed, well-built 100w amp.

[m-fine]

My math was correct. A 91 db speaker at 4 meters will require 500 watts to hit reference peaks.

The 85 db speaker in your example will need 256 at a close seating distance of 2m. If you sat 4 m back you would be looking at 1000w.

Whether an amp is current or voltage limited, the fact is you can easily run out of power with typical receivers and HT amps before you hit reference level peaks in movies, and with dynamic music recordings at very listenable levels.

I would expect the XPA-3 to make a significant difference over a 100 watt per channel receiver, even a very good one as far as max clean power. What I do not know is what the SQ characteristics of the XPA-3 are and if it will give the extra bottom end the OP is looking for.